text:
Is there any conclusive study relating the food consumed and the occurrence of acne?
The internet says a million things about what to eat and what not to eat in regards to impacts on acne. For instance:

Refrain from dairy products.
Refrain from food heavy in unsaturated fat.
Refrain from too much sweet.
Consume fresh food (raw fruits & vegetables) but no cabbage and cauliflower.
No Alcohol
Etc.

My question is:
Is there really any relation between food consumed and the occurrence of acne?

The short and unsatisfying answer is no-- it remains controversial due to lack of high quality randomized clinical trials. According to an article in UptoDate, a reliable resource for many physicians, last updated September 2014, there is an association between acne and intake of milk in which milk components could exacerbate acne. Unfortunately, there have been no randomized clinical trials on this subject. According to the same article, "there is no reliable evidence that ingestion of chocolate is associated with an increased prevalence or severity of acne." In a similar light, the article continues on to say that "data on favorable effects of dietary factors such as zinc, omega-3 fatty acids, antioxidants, vitamin A, and dietary fiber on acne vulgaris are limited. Further studies are necessary to determine the roles of these supplements in acne vulgaris."
Reference:

http://www.uptodate.com/contents/pathogenesis-clinical-manifestations-and-diagnosis-of-acne-vulgaris?source=search_result&search=acne+and+food&selectedTitle=1%7E150#H8


text:
Why do pine stands exist?
I live in the midwestern United States.  I cycle to work, sometimes on heavily wooded roads, and I can't help but notice that in most places within the surrounding deciduous forests Pine and evergreen trees don't seem to be doing so well - the few that exist don't look too happy.
In some places, however, there are majestic stands of pines - often completely free of the "seasonal" variety of trees.
Why is this?  What allows the slow growing pines to out-compete the other arboreal denizens of the forest?  And generally in such particular areas?
Thanks, this is killin' me...

A lot of forest is planted... I've heard that here in Sweden around 95% of forest is planted rather than natural forest, I've not got a source available for that though

Forest Succession 101

Pines are actually fast-growing, shade-intolerant, early-successional species. When land is allowed to lay fallow after being cleared by fire, wind storms, human land use or other major disturbance, the successional sequence will begin.
At first only herbs and grasses grow, but eventually these are shaded out by shrubs and tree seedlings. In this setting, the limiting factor is typically light. Because pines are fast growing in the sun, they usually take over a field and develop a relatively dense even-aged stand.

Because the seedlings grow so well and densely, they usually shade out and prevent most other trees and shade-intolerant plants from growing. The result: a dense stand of mostly pines:

I'll note here that early on in this process (before processes of self-thinning really get to take off), you can end up with what are sometimes called "dog hair" stands. Also, if you see clear rows in the pine stand, that's a good indication the pines were planted.
Eventually (80-120 years), most of these pines will die and fall out of the canopy (both due to "natural" causes and additional wind, ice, pest, or fire disturbance). As large pines fall and clear large enough canopy gaps, shade-tolerant sub-canopy hardwoods can take their place. Because pines are highly shade intolerant, pines do not regenerate again in that stand (without another major canopy-clearing disturbance). The result: a mostly hardwood-dominated forest (with perhaps a few remnant older pines):

So...

The all-pine stands you're seeing are early on in the successional sequence.
The few pines (that "don't look too happy" because of age) mixed with hardwood ("seasonal variety") trees are in a mid-to-late successional stand.

Note: my answer addresses the description of your question -- it is due to succession that you see the forest stands you're observing. This example of secondary succession does not apply to all instances of pine existence (as your actual questions asks). That question would have a very complicated answer involving niche theory, succession, disturbance regimes, interspecific and intraspecific interactions, trait descriptions, etc. and would need to be addressed at numerous scales (biology, population dynamics, community interactions, meta-populations/meta-communities, landscape scales, etc.)

What about non natural forest - most forest these days is managed and has commercial interests. If @user1833028 has an exact location we might be able to rule that out!

@rg255 I've addressed that in my answer. You'll know it was planted if you see a conspicuous rows of trees. If there are no rows, then there's a pretty good chance those seeds arrived on their own (via wind)

In nature, species compete for resources like water, light, nutrients, etc. and need to find 'their place' in this struggle. According to niche theory, every species occupies a certain spot in the multidimensional niche space (the dimensions describe the number of environmental factors) where it performs better than any other species. If there would not be such a place, the species is doomed to extinction in free nature.
Let's look at the pine (Kiefer) and the beech (Buche), a common european deciduous tree:

You see that the beech outcompetes the pine under intermediately moist conditions, although these conditions are theoretically best suited for the pine  (physiological optimum). However, the pine can outcompte the beech at the extremes of the gradient (ecological optimum).
Now imagine many environmental factors and many species. Under the predominant conditions in the midwest USA, deciduous tree species are favored over confifers because they are the better competitors. If conditions change towards the more extreme (very dry/moist, harsh climate,...), the pine gains the upper hand and forms large stands.

So if pines compete better in drier areas, you might find that the soil around pine stands is sandier, and would drain better than the soil where pines don't do as well. If you want to research this, your state probably has a university extension program willing to do soil testing for a small fee, you might find something that distinguishes pine stand soil to non pine soil.

Also, sir, would these be local conditions, temporal conditions (ie, they became established for a period where they had the oppourtunity) or both?

Both is basically possible, especially if you take deliberate alteration of site conditions and competition into account (forestry). However, on the long run and under natural conditions the general site characteristics will dominate temporarily beneficial effects. In general, trees are better adapted to stable conditions, whereas other plants like annuals or biennials are specialized in colonizing very unstable habitats. Trees aren't that good in taking advantage of short-term fluctuations.

But note that in different conditions - for instance the mountains of the US West - evergreens (pine, fir, cedar &c) almost totally dominate the landscape.  The only large deciduous tree is the aspen, and it's restricted to wet area such as meadows and along streams.  The rest are basically shrubs.

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text:
What is the origin of the name "λ phage"?
The lambda bacteriophage which infects E. coli was first discovered by Esther Lederberg  in 1950.
However, in the earliest paper on the lambda phage that I could find, I was unable to find the reason behind why the phage was named after the Greek letter λ.
Is there a source (by Lederberg or previous scientists) that mentions the etymology of this phage?

The original paper from Lederberg from January 1953 (see reference 1) indeed doesn't mention the origin of the name, but the paper in reference 2 does. It says:

The isolation of λ was first reported in 1951 by Esther Lederberg
  (119), then a Ph.D. student at the University of Wisconsin, and later
  was described, in greater detail, in a 1953 Genetics paper by Esther
  and Joshua Lederberg (120). The discovery was accidental, when a
  λ-sensitive strain of Escherichia coli K-12 (W518, obtained after UV
  irradiation) was crossed with its parent. The mixture yielded plaques,
  and the source of the virus was the K-12 parent. W518 cells that
  survived infection became stable lysogens which, like the K-12 parent,
  were immune to superinfection and which released unaltered phage.
  Although the Lederbergs were initially opposed to the notion, crosses
  between lysogens and sensitive cells led them to suggest that λ
  prophage was chromosomal and linked to gal. Joshua Lederberg recalls
  that he was convinced, from earlier work of Burnet and Lush (21), that
  lysogeny was a real phenomenon but that he “fully expected lambda to
  be a [plasmid]—in fact the term lambda was modeled after Sonneborn's
  kappa [in Paramecium; see reference 156 for a recent review], so it
  was quite a shock to discover the contrary.” (In fact, years later
  Hideo Ikeda and Jun-ichi Tomizawa [98] showed that prophage P1, unlike
  λ, is a plasmid and not part of the host chromosome!)

The mentioned kappa particle in Paramecium is an inheritable cytoplasmatic symbiont and the Lederbergs thought of something similar for their discovery. My assumption here is that lambda was the next greek letter, hence the name. The publication in which Sonneborn describes Kappa can be found in reference 3, a short historical overview on the discovery of Kappa in the review in reference 4.
References:

Genetic Studies of Lysogenicity in Escherichia Coli.
Little lambda, who made thee?
Mating Types in Paramecium Aurelia: Diverse Conditions for Mating in
Different Stocks; Occurrence, Number and Interrelations of the Types
R-body-producing bacteria.

Thanks for the well-researched answer! However, I didn't manage to find anywhere in the second paper mentioning that the phage was named lambda because it was the next letter after kappa.

@MarchHo There is indeed no direct source for that - this is my assumption. But I think it is logical, that's why I wrote it. I will edit the question and make that clearer.

@MattDMo This answer did not answer my original question, and therefore I will wait for further answers.

@MarchHo Obviously greek letters where quite commonly used for cytoplasmatic factors, see this review - the relevant piece is on page 114, right column in the upper part of the page.

My assumption is that a Lederberg discovered the Lysogen, and lambda in the Greek alphabet translates as the letter 'L' so it could be a Greek 'L' for Lederberg, or a Greek 'L' for Lysogen, or better yet a Greek 'L' for both. All of the people who were involved are deceased, so if they didn't write it down . . . . Look at all the various explanations for the origin of the name of the amber stop codons. It happened so long ago that the people who selected it don't even remember the circumstances.  Now the origin of the name of the lambda cohesive end sites as cos, that we know.

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text:
Identify this indoor plant with strange stem-like leaves
It appears that this plant branches multiple times from the base of its stem; however, I'm not sure if the base stems are from one organism. It becomes yellowish in color at the tip each stem-like leaves; one node can branch 3-4 leaves at a time.
Additional information:
As for the specimen location- I am currently living in Japan and this plant was bought as a gift for me. It probably is imported from other countries since it doesn't seem to be native here. For maintenance; I was told to just cut the tip of the leaves if it began to fade in color and die; and water the plant at least once a week.

What's your location?   2.  What happens  when  you  break off a stem?

Thanks for accepting my answer --  I'm glad it answered your question. However, please update your question with the information I requested in my previous comment so that the question can serve better use to others in the future. In general, species ID questions should always contain some information about the specimen's location. Thanks

Looks like a Pencil Tree (Euphorbia tirucalli), sometimes called "pencil plant", "pencil cactus" or "milkbush." This "leafless-looking" plant is not actually a cactus, but actually a "Euphorbia" (i.e., member of the Euphorbiaceae family), and should present a white "milky" liquid latex when broken.

CAUTION: THIS IS A POISONOUS PLANT [See symptoms here].

Description: A succulent, spineless shrub with round, green branches; leaves clustered at the tip of the branches and soon dropping

Although it eventually can grow into a small-sized tree in its natural habitat, this plant is found more commonly as a medium-sized house plant or landscaping "shrub."

Range: Tropical Africa and India

Euphorbia tirucalli is very well adapted to semi-arid conditions, but also occurs in both dry and moist forest, savanna and shrub land, and withstands salt stress associated with coastal conditions, but no frost. It occurs from sea-level up to 2500 m altitude. It grows well on a wide variety of light-textured, neutral to acidic soils. It is commonly associated with human settlements and becomes naturalized rapidly. It is locally common and often occurs in groups. [Source].

I would say it looks like some kind of Rhipsalis. Which exact species i can't tell. Just search for images of Rhipsalis and compare to yours.
EDIT:
Some time ago i had a specimen of rhipsalis baccifera which looked a lot like your plant but wasn't as self supporting as yours. It was hanging down below its pot. But maybe yours is some kind of subspecies.


text:
translation of scientific names
I am trying to determine the "translated" meanings (not seeking the common names) of different insects, (presently some bees and wasps).  Does anyone know of a printed or internet resource that defines the various names. I have one for plants, but not for animals.  Knowing the (English) meaning of the Latin / Greek/ etc. is often very informative -- IF I can find it.
I can give more specifics if you want.
Thanks.
Glen B
Olympia WA, USA

All you need to do is use a Latin/English and/or Greek/English dictionary. This is not really related to biology but linguistics.

This question appears to be off-topic because it is about nomenclature and the meanings of words in dead languages, not biology.

what OP meant by latin and greek names is the binomial nomenclature (which for historical reasons is in latin and greek)

There are multiple resources that are in use as far as I can see from a quick google search. You would find the Integrated Taxonomic Information System (ITIS) quite useful. It includes details on scientific papers published about a specific species.

Glen, sometimes there are many species that have same colloquial name. For e.g. frog includes hundreds of species. If you require high level of detail, you may need to look for more comprehensive lists.
There are zoology dictionaries such as this. I think it should serve your purpose.


text:
Did baby bird hair and mammalian hair convergently evolve?
Chicks (baby of chickens) and ducklings seem to have fine hairs, at least something that look like hairs to me. Most mammals have hairs, but reptiles, fish, or other animal groups do not have hairs as far as I know.
I have looked up the tree of evolution, and it looks like this.

So, the tortoises, crocodiles (I do not know what lepidosauria means but I guess it is reptiles other than the aforementioned), and birds diverged after their common ancestor was split from the common ancestor of mammals.
Since none of the tortoises, lepidosauria, or crocodiles have hairs now, does this mean that the hair of birds and mammalian hair is an example of convergent evolution? Or did these other taxa lose hair during evolution?

Fledglings do not have hair, but "down" -- a very, very fine type of feather used to insulate the chicks (and convergent in purpose with mammalian hair there).

Is there any significant difference between hair and down?

I advice you to have a look into the commonalities (chemically, functionally and evolutionary) between feathers and hair and forget about feather-down. That should get you a lot closer to the bottom of things and will lead to a better question.

Hair, feathers, fish scales, shark armor - they're all skin cells.

Bird "baby hair" are modified feathers.  (Or perhaps feathers are modified "baby hair".  The ancestral state for feathers was probably closer to the chick's down in appearance, but I don't know whether chick down is unmodified original feather or whether it was feathers and then modified again.)
In any case, mammalian hair and dinosaur feathers (which includes bird feathers) are separately evolved from the same base structure, modified reptilian scales. They are therefore homologous, but evolved independently.

These results reveal a new evolutionary scenario where hairs, feathers, and scales of extant species are homologous structures inherited, with modification, from their shared reptilian ancestor’s skin appendages already characterized by an anatomical placode and associated signaling molecules.

--The anatomical placode in reptile scale morphogenesis indicates shared ancestry among skin appendages in amniotes

iayork's answer is a good one, I will add one thing: Mammalian hair doesn't show up in the fossil record before the Late Permian; Feathers for their part have not yet been found outside of Dinosauria, a clade which started in the Triassic (which came after the Permian).
The common ancestor of Mammals and Dinosaurs however existed in the Carboniferous, around 312 million years ago, which is 12 million years before the beginning of the Permian and more like 50 million years or so before the earliest fossil fur found so far (I couldn't find a date more precise than "Late Permian" but the Permian ended 252 million years ago).
Add to this that the common ancestor of Mammals and Dinosaurs is also the common ancestor of basically all fossil tetrapods that weren't amphibians, and no fur or feathers have been found on any of those outside of a few Dinosaur groups and the Mammal lineage, that no feathers have been found in any ancestor of Mammals and no fur has been found in any ancestor of Birds... It is pretty clear that the common ancestor of Birds and Mammals had neither fur nor feathers, meaning those features evolved convergently.


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Can a ladybug be determined just by its number of points?
I saw a ladybug on my balcony one day and I just counted the dots.
There was 18 black dots on a red/orange elytra.
The location is in Europe (Geneva, Switzerland) and usually we have quite different endemic ladybugs and also the invasive asian ladybug Harmonia axyridis.
I did not found any local ladybugs with such dot counting except articles saying the Harmonia axyridis can be found with a lot of variations (elytra  color, points or stripes, etc...).
The question is: Can I be sure that a ladybugs with 18-points (found in Europe area) is of the genus Harmonia axyridis?
Note that I have a picture of the animal but I want to focus my question on the number of dots exclusively.

No, most of the time you cannot. There is a large diversity of ladybug species (several dozens in western Europe), and many of them can have the same number of spots. Moreover, as you already said, there can be intraspecific variation in the number of spots.
I do not know if there are specific numbers of spots that would be associated to only one species - but for most numbers, it is not the case. For instance, yes, it is common for Harmonia axyrids to have 18 spots (source). But Anisosticta novemdecimpunctata, which  can also be found in Europe - and can also be orange ! - may have between 15 and 21 spots (though it more frequently has 19) (source).
Thus, the number of spots cannot be used as a sole criterion to identify ladybugs: other criteria usually include the general shape, colour of elytra, size, shape and colour of the pronotum, length of antennae, etc. (See here for examples.)
First picture: Harmonia axyridis

Second picture: Anisosticta novemdecimpunctata

You're right, you found a potential species that have the same number of spots. Another criterion would also be the distribution (the Anisosticta novemdecimpunctata seems not  present in Central Europe). Accepting the answer then.

Actually it is present in all Europe (although not as common as H axyridis) see here for instance:
https://fauna-eu.org/cdm_dataportal/taxon/e8c617e8-591c-466b-8f0d-6ecf4411c72f
Distribution + number of spots are often a good proxy, but one must be cautious about intra-specific variation in the number of spots.

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text:
What is the term for being younger than the body age?
I remember that I once attended a seminar in which the speaker talked about the heart rate of different kinds of butterflies. Normally, the heart rate of the adult butterfly will be more complex than the heart rate when it is in the larvae form. However, there are some species that have complex heart rates even when they are in the larvae form, and there are others that have simple heart rates even when they are in butterfly form.
So if we are talking about the butterflies' heart, we can say that some species' heart are younger than their real age, while others are older than their real age. What is the name of this phenomenon?

I'm very confused about what you are asking.  Your title is about "being younger than usual" and your question seems to be about either the rate of heartbeat or the complexity of heartbeat.  I would suggest posing a clearer question.

I'm not sure about a general biological context, but an old word for looking younger than one's years is neanimorphic.  A search on pubmed found zero results for this, so it is probably not the term you are looking for.

Well looking younger or having features of a youngling is called neoteny but I don't think you are referring to that.

@WYSIWYG yes, that's the word I'm looking for. May I ask why you don't think I'm referring to it?

Neoteny

Neoteny (/niˈɒtəni/), also called juvenilization, is the delaying or slowing of the physiological (or somatic) development of an organism, typically an animal. Neoteny is found in modern humans. In progenesis (also called paedogenesis), sexual development is accelerated.
Both neoteny and progenesis result in paedomorphism (or paedomorphosis), a type of heterochrony. Some authors define paedomorphism as the retention of larval traits, as seen in salamanders.
Both neoteny and progenesis cause the retention in adults of traits previously seen only in the young. Such retention is important in evolutionary biology, domestication and evolutionary developmental biology.


text:
How is it decided what type of food we want to eat?
How is it decided what type of food we want to eat? For example, sometimes you would like to eat some sweets but not a full meal, other times you'd like to eat some fruit, sometimes not and so on.
I have read somewhere that organism can detect whether we are hungry or not and it gives the effect so that we feel that we are actually hungry. But the question is: is there something that measures for example what is level of glucose or aminoacids or some fats in blood and specifies not only whether we are hungry or not but also what type of food we should eat to replenish lacking resources?

I'm no biologist but here are two answers to your multidimensional question. "How is it decided what type of food we want to eat?"
There is new research into neuroscience and microbiological science about a phenomena where bacteria in our gut that produce vitamins and digest things that we cannot digest, contribute to the choices we make for our diet. Don't ask me how, but from my understanding they must somehow communicate with the brain to release dopamine while stimulating neurons responsible for choosing a certain food to crave. "Is there something that measures for example what is level of glucose or amino-acids or some fats in blood...?" Well yes actually, let's take the pancreas for example. It knows when blood sugar is high from digested materials and will begin to produce insulin. I won't go much further because already there is a response based on the detection of sugars. Your entire digestive tract is based on these detective processes in order to appropriately digest and react to digested material. Are there processes that tell your brain what to eat next? Well besides the bacteria, there are plenty of hormones produced by your gastrointestinal tract such as Ghrelin which is the most common "hunger hormone" and is responsible for homeostasis aka energy regulation/distribution throughout your body.
It's better not to ask how but to ask why when researching topics similar to this, the how is almost always provided. I'm not entirely sure how those hormones communicate with the brain, my knowledge of the brain is less biochemical and more neurological (e.g. neuron formation).


text:
Why do plants fruit?
This is a two-part question:

What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)?

I changed the name from "What's the point in bananas?" because, despite being an awesome title, the new one is a bit more biologically grounded.

A lot of times, the fruit flesh is good for more than just feeding people; it can provide a nutrient-rich environment for the seed itself to begin germinating in.  It's not too different from an egg, where the yolk is the part that turns into the chicken, in its entirety, and the egg white is purely food for the developing chick.

Fruit being eaten is a very useful attribute for a plant, just like pollenisation through provision of nectar is often better than wind dispersal. Seeds contain startch and sugar, so seeds are always attractive to animals, so plants with fruit actually dissuade animals from eating the seeds, and encourage the fruit to be eaten in such a way as to be dispersed by the right animal. Fruit are essentially designed like ideal dispersal devices for fruiting plant's and berries seeds, like wings are to designe to wind dispersed seeds. Fruit are the wings of the seed.

Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
From above you can see there are many ways to spread a seed. This means that many plants (those that do not use fruit) will want (from an evolutionary perspective) to avoid being eaten at all costs, and therefore evolve poison/taste cues that reduce the frequency of this. However, if investing in producing fruit bears a net benefit, ie many seeds are spread and successfully propagate, then the cost of fruit production is not a risk. A fruiting plant can minimize the risk by limiting reward (making fruit taste good and be nutritious) to only the right spatiotemporal moment when the seeds are primed for dispersal, if the fruit is eaten before the seeds are ready/present in the fruit then there will be no benefit of producing the fruit. (I expect this is why unripe fruit doesn't tend to taste so nice - it doesn't taste nice unless it's ripe because those where mutations made fruit taste good before the seeds were ready had no offspring, and those that time the ripening well were much more successful).
Producing an edible fruit is not necessarily the best way but is the way many plant species have evolved to spread their seeds. Evolution works by random mutation and selection, which can only work with the variation it has available - only if a mutation to produce fruit arises in a species and it improves fitness is it then likely to spread. It appears that endozoochory could be a very good methods of long distance dispersal.
Some interesting stuff
Interestingly, according to this blog post, unripe fruits taste bitter because they are full of tanins. Cranberries are an odd fruit because they taste bitter which means they are unattractive to animals, but they do float - which is a good dispersal method - because of an air-pocket inside the fruit that evolved. It could be the case then that once a mutation arrived for the air-pocket the fruit could just float away on water to a new location, and then using resources to make the fruit sweet and tasty became an unnecessary cost so was lost (to some degree).
This article contains this text:

Like many species of plants native to North America, the cranberry is specially adapted to wetlands -- water-soaked areas that create transition points between dry land and open water. But cranberries do not grow directly in the water. Instead, they typically lay their roots at its edge, taking advantage of the rich soils created by alternating layers of peat, sand, clay and rock.
  Other fruits are dependent on hungry creatures to spread their seed,
  so sweetness can help their chance of being eaten and transported
  elsewhere. Not cranberries. Because of their little air pockets, the
  fruit falls from the plant's long vines when ripe and lets the water
  transport it to distant beds.
This advantage dictated the fruit we eat today.
Blueberries and cranberries are close cousins and are in fact not
  berries at all; they belong instead to a class of fruits known as
  epigynous or false berries. Unlike a true berry, the fruit grows from
  beneath the rest of the flower parts and as the fruit ripens the
  flower stays attached and ripens as well.
Vorsa believes that at some point during the last ice age there were
  fewer animals to eat the fruits, and this might have driven the two
  species to diverge. The cranberries developed an acidity level five
  times higher than blueberries because it came to rely on water for
  seed dispersal. Cranberries did not need to produce large amounts of
  sugar that their blue-colored relatives required to entice consumption
  by animals in order to spread their seeds.

"the plant hasn't made it taste good because it doesn't want it to be eaten" be careful with this line of thinking. The reality of evolution is that the plants that made their fruit taste good, before or after their seeds were ready, died off. The ones that happened to have the right flavor at the right time managed to survive.

@zzzzbov that's what I'm getting at - I'm not suggesting plants "want" or choose. It's meant from an evolutionary perspective, ie as you say "The ones that happened to have the right flavor at the right time managed to survive"

@zzzzBov this is an important point that is typically assumed. This assumption should probably be adjusted based on target audience and the level of the question/answer. Physicists talk in the same way about what systems "want" to do. It's a fairly idiomatic way of describing a tendency or trend, but may be confusing to those with little scientific background.

@zzzzBov I will edit the answer next time I'm at the computer to clarify

I see no reason why a plant couldn't change the advantage gained from having animals eat the fruit and spread the seeds to restricting consumption by animals due to risk of seed destruction. Evolution is by nature dynamic! What worked a million years ago might not work today. If a fruit is appealing enough that most seeds get destroyed by being eaten but a variety evolves which is poisonous, bad tasting, has prickles or thorns or any other discouraging feature and that is enough to ensure survival then that variety will tend to become dominant.

It's also interesting to mention chili peppers, whose seeds can be digested by mammals, but not by birds. Birds lack the ability to sense capsaicin, the molecule that makes chili peppers hot.


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Why are Oxyuranus snake species named Taipan?
It is interesting, why are Oxyuranus species called Taipan. The snakes are Australian but taipan looks like of Chinese origin word (it means big shot - important person).

An answer is found at the Wikipedia page for Taipan:

The common name, taipan, was coined by anthropologist Donald Thomson after the word used by the Wik-Mungkan Aboriginal people of central Cape York Peninsula, Queensland, Australia.

This passage is citing Sutton. 1995. Wik Ngathan Dictionary as support. I cannot evaluate the truth in this statement though.
For another reference see McKnight. 1981. The Wik-mungkan concept Nganwi: a study of mystical power and sickness in an Australian tribe. Bijdragen tot de Taal-, Land- en Volkenkunde 137, which refers to Taipan as the Rainbow serpent (an Aboriginal mythical creature) of the Wik-Mungkan tribe.
Even more folklore is found in McNamee. 2000. The Serpent's Tale: Snakes in Folklore and Literature in "Taipan the snake and the blue-tongued lizard".


text:
What is Growing on These Tree Leaves? (Image)
I found a seemingly diseased tree when I was out playing tennis yesterday... What is growing on this tree leaf? Is this a disease? If so, is it contagious? I have zero knowledge in botany, but I'm curious about what is happening to these trees. :)

I'm just wondering if you still play tennis in that location to confirm if you see any Juniperous virginiana (eastern red cedar) nearby.

This is actually not a gall as other answers have suggested.
This is likely a fungus called Cedar-apple rust (Gymnosporangium juniperi-virginianae).
The fungus only thrives in the presence of both Juniperus virginiana (Eastern red cedar) and apple (Malus spp.) trees.
The leaf in the picture belongs to some species of the apple genus and the growths are aecia of G. juniperi-virginianae. You can read about this interesting fungi through Rutger's Plant & Pest Advisory here.
You can see a picture of the fungi here, and I've included Sabrina Tirpak's (Rutgers PDL) photo of its aecia below:
http://plant-pest-advisory.rutgers.edu/3859/
Below is a visual of the telia of the rust fungus on J. virginiana:

 (Photo source: Ada Hayden Herbarium)

What a fascinating organism!

Right?! I've never seen the tentacled glob that grows on the Juniper

That's so cool :)

Briefly, these look like insect galls; which are reactions of plant tissue caused by parasitic insects (often wasps) laying eggs inside the leaf. I'm sure someone can answer in more detail, though!
Cf. How do plant galls form?

Would the tree die because of this? Most of its leaves are growing "insect galls"...

I imagine that it depends on the galling species and tree species, but most leaf galls don't hurt trees


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Meaning of the word Oleracea
What does "oleracea", as appears in numerous plant species (scientific) names, mean? Examples: Euterpa oleracea, Brassica oleracea, Portulaca oleracea, Acmella oleracea, Spilanthes oleracea.

It means "vegetable".
I think it's because people use those plants for food


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Identification: tall conifer with tamarisk-like leaves
I am looking to identify a conifer that I found in a public park. Please see below for pictures of the leaves, bark and habit (click for full-size view).
I normally use Pl@ntNet for identification, but in this case it fails: it would only suggest French tamarisk or other tamarisks based on the leaves. But those are more like shrubs, while this was a tall tree, very comparable in shape and size to the bald cypress (?) standing a few meters from it. The upward-curving leaves shown in the picture may not be entirely typical, but this small lone branch was the only one I could reach to take a photo.
Additional information:

Location: Dresden, Germany.
Google street view link, it's the one on the right.
Leaf size: about finger length.

@theforestecologist Updated as best as I could. I really can't put a number on the height, but it's a "tall tree", as you can see on the Google street view link I just added.

This looks like pond cypress, Taxodium ascendens, (sometimes considered a variety of bald cypress: T. distichum var. imbricatum).

 Source: Wikipedia ; Credit: NOAA (2005)
The specific epithet, ascendens, comes from the fact that the plant's awl-like (sumbulate) leaves (3-10mm long) tend to grow along erect ("ascending") green stems ; whereas bald cypress (T. distichum) tends to have leaves that grow in a more distichous growth pattern.
The bark also tends to be greyer than bald cypress, but retains fibrous/shreddy bark that can become furrowed with age:

 Source: Ebben Nurseries
You can see multiple high-quality photos on Will cook's Carolina Nature site.

For example, this image showing the peely and furrowed bark.

Although native to the SE US, I found numerous records of this tree being planted in Germany (e.g., inaturalist). The Dresden Garden also mentions housing Taxodium trees here.


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What kind of caterpillar type bug is this?
I've made a photo using the reversed 58 mm lens and my cropped DSLR:

Could you please help? I really don't know where this came from.
I found it in Russia.

Cannot help you but maybe it could be useful if you specified where you found it (inside, outside, which country, when, etc.?)

I found it in my kitchen on a clean plate from IKEA :) Country is Russia.

Likely to be a black carpet beetle larvae

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7436.html
For more facts try: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7436.html
Don't worry though, they live everywhere!
Wikipedia has some info on the family of beetles that they belong to (http://en.wikipedia.org/wiki/Dermestidae). I don't think they really cause any harm, except in natural history museums where they tend to munch the collections of animals...although this can also be a good thing:
'They are used in taxidermy and by natural history museums to clean animal skeletons' 1
1 VanClay, Mary. "Bitten By the Bug". www.johnsonstring.com. Retrieved November 10, 2012.

Definitely Dermestidae, but Dermestes lardarius (Larder beetle), Attagenus pellio (Fur beetle) and Anthrenus museorum (Museum beetle) are all common and likely. They can all be pest, also outside of museums, on e.g. fabrics, fur etc., but most that you find inside you house come from the outside. It might be worth the effort to check your clothes, other fabrics, stuffed animals or other suitable substrates if you find many of them.


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What insect is this?
I found it in Russia.

Where do they usually live? What do they eat?
Full length is approximately 2 cm.

Seems to be it's a Woodlouse!
http://en.wikipedia.org/wiki/Woodlouse

And, of course, whatever it is it isn't an insect.

Indeed, by true definition you are looking at a crustacean instead of an insect. The differentiation can be made because crustaceans are biramous, meaning their "legs" have two segments instead of the typical one in most insects.

@MichaelCannon.. arachnid perhaps ??

@WYSIWYG it has 12 legs, arachnids have 8 by definition. The woodlouse/pill bug is in the subphylum of Crustacea.

and interestingly, woodlice are said to be delicious in a soup!

This is a terrestrial isopod crustacean called a woodlouse (colloquially referred to as pill bugs, potato bugs, roly-pollies, sow bugs, etc.).

There are over 5000 species in the world with at least 64 in Russia (see Kuznetsova & Gongalsky 2012).
Habitat:
Woodlice are typically found in damp, dark places -- in the soil, under rocks/logs/debris, etc.

Living in a terrestrial environment, woodlice breathe through trachea-like lungs in their paddle-shaped hind legs (pleopods), called pleopodal lungs. Woodlice need moisture because they rapidly lose water by excretion and through their cuticle, and so are usually found in damp, dark places

Description:
As with all Arthropoda, the woodlouse is a segmented animal with a rigid exoskeleton and jointed limbs.

However, this is not an insect! Insects have 3 pairs of legs while isopods have 7 pairs of legs.

The extended uropods on your specimen as well as the pereon-pleon junction, number of antenna flagella, etc. all are important for IDing to species. (E.g., see here).
Note: although many people associate these arthropods with the ability to roll up into a perfect ball, only woodlice in the genus Armadillidium and in the family Armadillidae can roll up into an almost perfect sphere as a defensive mechanism.
Diet:
Woodlice are generally detritivores, meaning they eat decaying organic matter.

Citations:
Kuznetsova, Daria M., and Konstantin B. Gongalsky. "Cartographic analysis of woodlice fauna of the former USSR." ZooKeys 176 (2012): 1.


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What insect is in this photo?
Found in Russia, in the kitchen. It is about 1–2 cm length.

This is an immature "True Bug", order Hemiptera. You can tell this from the general shape of the wings, and from the big "beak", a feature of the Hemiptera.
Within Hemiptera, it's possible that with those enlarged front legs, it could be an Assassin Bug, family Reduviidae.

This isn't a nymph, but a short-winged adult; enlarging the second photo shows that the front wings are not fused to the mesothorax (which would be the case in a nymph).

It may also be a squash bug, they look pretty similar. They even have enlarged front legs too.


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Sex differences in response to food deprivation
This question was inspired by a casual conversation with friends the other night. Some of us had noted that women tend to eat smaller meals more often (snacks, fruits etc) while men eat larger portions more infrequently. Also, several of the women said to be sensitive to food withdrawal, getting very hungry after a few hours and experiencing low blood sugar symptoms (even fainting in one case) if not eating regularly, for example if skipping lunch. Men (including myself) seemed to be less affected, often skipping meals without noticing.
This was a highly unscientific investigation with a tiny sample size :)  just based on our personal stories and friends we know. It could, of course, reflect attitude/perception/habits rather than actual biological differences. It should also be said that not everybody agreed -- some men also stated that they felt sensitive to food withdrawal. But there are of course known differences in metabolism between the sexes, so it doesn't seem entirely implausible. It might also be related to different body mass, muscle mass, etc.
So my question: is there any scientific evidence that women and men react differently to short-term food withdrawal? Here short-term would be, say, up to 24 hours, as when skipping breakfast and/or lunch. Are there any data on differences in blood glucose levels after food withdrawal, for example?

Don't know about people, but can tell you about fruit flies if you're interested.

@David,  sure, if there are differences in other species that's interesting too.  (Though I'm not convinced flies are the best model for this  ;-)

No, I agree — not a good model. As there are distinct male/female patterns for activity, the expression of genes for enzymes that metabolise sugars (such as the maltase family) show pronounced sexual dimorphism.

Well, there are at least some studies that indicate that men and women have different metabolic response to fasting... but to give a decent answer would require a large litterature study... Here is a paper concerned with blood level glucose albeit with 36 hours of fasting. https://academic.oup.com/jcem/article-lookup/doi/10.1210/jc.2007-0552

I have no significant sample size either, but in my peer group behaviour is directly opposite. Males are constantly snacking and get cranky fast when skipping meals, females eat more regularly, but also do sometimes skip a meal without problems.

@JeppeNielsen,  thanks for the paper link, it's very helpful!

There are very few studies about the gender-based differences in response to food deprivation in humans (or at least I didn't find many such reports).
In one of the papers, Sodersten et al conducted a research on 30 (17 women and 13 men) high school-aged subjects. After a short-term fast (skipping 2 successive meals), males consumed much more food while women actually ate less, when compared with their respective baseline quantity of meal. They suggested an inherent difficulty for women to compensate a period of fasting by increasing their food intake. They, thus, concluded that fasting might be more risky for women than men as this may start them down a self-sustaining pattern of reduced calorie intake. You can see the reference from Yamada's Textbook of Gastroenterology.
In another study, Soeters et al, 2007 showed that after a period of fasting for 38 hours, women had low plasma glucose levels than men, although they have higher amount of free fatty acids in plasma. They suggest that women are somehow protected from free fatty acid-induced insulin resistance, probably because they prevent myocellular accumulation of ceramide.
A yet another study, by Wu et al, 2011, touches upon the point that the relation between kilojoules consumed and kilojoules utilized is different in men and women. They also state that women consume less kilojoules per kilogram lean mass and store more fats in their body, especially during gestation period, as compared to men (I'm obviously not comparing the gestation period). This finding can, in a way, support the observations by Sodersten et al (see first paragraph).
If you want a more detailed report, you can have a look at this report from United Nations University (old website) by Sara R. Millman and Laurie F. DeRose. They discuss in detail why and how women and children are considered the vulnerable groups in times of long-term food deprivation since they are more likely to express hunger and have more serious probable consequences of hunger in times of food scarcity.
If you can expand your terms a little bit, there are (comparatively) many such studies on rats and other animals. For example, Sarookhani et al, 2014 measure the effects of food deprivation on formalin-induced nociceptive behaviors and $\beta$-endorphin and testosterone concentration in rats. You can find many such studies quite easily. However, I'll keep searching and adding more related studies on humans here.

Thanks, these are very useful pointers. It does seem like there is not much data out there.  (Hmm, now I'm thinking of doing my own study :)

@roland sure, I'll be happy to read it ;)

There is a big body of literature in one specific instance of fasting: Ramadan. While not as nicely controlled as most fasting studies there certainly have been a lot of parameters investigated and if there are any differences between men and women.
A quick Google scholar search unearthed this article by Finch et al. with the following in the abstract:

Rated hunger increased substantially during the daily fast, and hunger was higher for the women than the men during the earlier days of Ramadan, whereas later, on average, fasting levels of hunger were very similar for both sexes

But I agree with Jeppe Nielsen, you will have to do a long thorough meta-analysis to come up with solid statements, sample size appear rather small.


text:
How can soft tissue exist in dinosaur fossils?
In this article the author explains that they found soft tissues inside of 68-million-year-old dinosaur fossils. How can that be possible? It was believed that soft tissues cannot last more than a million years and that DNA degrades even sooner.

Our findings challenged everything scientists thought they knew about
  the breakdown of cells and molecules. Test-tube studies of organic
  molecules indicated that proteins should not persist more than a
  million years or so; DNA had an even shorter life span.

What is the evidence that the fossils were real?

In a nutshell the organic matter got encased in such a way that oxygen was limited at first and ultimately the casing materiel sealed the organic matter left completely off from oxygen.

This question seems more sutable for Biology.SE than here.

@MaxW, you are smarter than scientists because they would never think of that.

@Ilya Melamed, ok let's migrate

keratin and collagen are an incredibly tough molecules so if it is isolated from the environment (oxygen and bacteria) it could easily survive for that long. Not all proteins are equal some are very robust other very fragile. We have long known protein and carbohydrates can survive for incredible lengths of time under the right circumstances, amber is famous for it. Rapid deposition of minerals can produce a similar if less powerful result.
In this case the keratin was encapsulated by water deposited minerals that sealed it away from the outside environment. There are other examples as well, natural mummification can lead to some preservation in the form of biofilms and impressions. But the most dramatic are amber encased specimens. Amber is a quick forming and creates a perfect air seal.
here is a dinosaur tail preserved in amber.

"The bone slice was from a dinosaur that a team from the Museum of the Rockies in Bozeman, Mont., had recently uncovered—a Tyrannosaurus rex that died some 67 million years ago—and everyone knew organic material was far too delicate to persist for such a vast stretch of time. " it doesn't seem the sample was preserved in keratin.

I think I found the answer http://www.livescience.com/41537-t-rex-soft-tissue.html

not preserved in keritin, MADE of keratin, I assumed you were referring to the discovery of beta keratin in dinosaurshttps://news.ncsu.edu/2016/11/moyer-claw/. In the case of the study you are referring to the material in question is collagen which is also very tough. It is the rapid mineralization of rhe fossil that seals the bone.

in the link I provided they talk about iron which creates formaldehyde and that can preserve tissue. It's just little funny to me how easily they can find the answer and the whole community takes it as solved.

I was part of that community, if you think figuring out how it happened was easy you are mistaken, there were dozens of paper back and forth. Several argued that that particular piece was not even original but a bacterial byproduct, it is still not confirmed to be original, That is why I assumed you were talking about the beta-keratin finds they are unmistakably original material. And remember you are looking at the editorial about the science not the original research.

lol, you are a joker. It should take something like to build a hydron collider to test and prove these theories and you say it took some dozens papers going back and forth?

You don't understand what testing means, testing does not mean reproduce in a laboratory. Ask another question about it so someone can answer or try reading up on it, http://www.brynmawr.edu/geology/documents/scientificmethodCleland.pdf


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Nutrient limitation in terrestrial and freshwater ecosystems
In terms of primary production, it is often described in textbooks that nitrogen is the most limiting nutrient in terrestrial ecosystems, while phosphorus is the most limiting nutrient in freshwater ecosystems. What creates this difference?

Can you provide references to these texts

Tropical terrestrial biomes can actually have more of a shortage of P vs N.

The traditional explanation for this is that nitrogen compounds are more mobile than phosphorus compounds. As a result, nitrogen is more likely to flow through terrestrial ecosystems and accumulate in freshwater ecosystems, making P relatively more limiting than N in freshwater.
Phosphorus compounds (e.g., phosphate) are more "sticky" and tend to bind/sorb to compounds in the soil and aquatic sediments, e.g., ferric compounds. Thus, most phosphorus gets bound up in terrestrial ecosystems because it's less mobile than nitrogen, or gets bound up in aquatic sediments. As a result, nitrogen becomes relatively more limiting than phosphorus in terrestrial ecosystems, and the phosphorus that does enter freshwater ecosystems often becomes inaccessible to biological organisms like primary producers.
Note that this paradigm is a generalization, and is dependent on many other factors. Lake pH and concentration ferric compounds can regulate whether the sediments are sources or sinks of P; anoxic conditions can lead to denitrification, a loss of N that could offset N inputs. Anthropogenic additions of N and P (either to the freshwater system directly or to the terrestrial ecosystem that drains into it) could dramatically perturb the natural balance between N and P limitation in terrestrial and aquatic ecosystems in a way that does not conform to the paradigm.
Some references you might find useful:
Elser, J. J., Bracken, M. E.S., Cleland, E. E., Gruner, D. S., Harpole, W. S., Hillebrand, H., Ngai, J. T., Seabloom, E. W., Shurin, J. B. and Smith, J. E. (2007), Global analysis of nitrogen and phosphorus limitation of primary producers in freshwater, marine and terrestrial ecosystems. Ecology Letters, 10: 1135–1142.
Vitousek, P.M. & Howarth, R.W. Biogeochemistry (1991) 13: 87.


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What biological processes can affect the temperature of the shadow a tree casts?
Assuming two trees have similar shape and leaf coverage, could differences in the biological processes among them lead to differences in the temperature of the shadow they cast?
What biological processes occurring in plants could affect this? I was thinking that transpiration will cause heat loss, and photosynthesis also absorbs energy, so these would contribute. What other processes that occur in a tree could affect the dissipation of heat causing cooler shade?
Has there been any studies specific to rates of transpiration and photosynthesis, and the effect on shade temperature?

please specify what you mean by quality of shade. also, probably, number of leaves in $m^3$ is not good enough: something like total surface of leaves in $m^3$ should be more useful

By quality of shade, do you mean something like $ΔT = T_{unshaded} - T_{shaded}$, the difference in temperature between a shaded and unshaded area?

From personal experience (I don't know that anyone has actually studied this), much depends on the air, not on the tree itself.  In humid lowland climes, shade may not be all that much cooler.  In a dry, high-altitude clime (like the Sierra Nevada, where I live), you can be hot in the sun, but want to put on a sweater when you move into the shade.

Density of leaves, humidity, general temperature, time of day/sun angle... various differences in human experience

@Luigi Yes, that is what I meant. Thanks for the tip. Will edit question to reflect it.

This is more or less a physics/general mathematics question. There may be some effect of transpiration but I think that would be small.

@WYSIWYG I thought transpiration has a major role in regulating temperature around trees

@rg255 thanks for the help. I have cleaned up the comment made by me

I don't think anyone has cared about this question in the literature sorry to say. It's kind of trivial. What may have drawn attention in the literature is why cities are always a few degrees warmer than non-urban areas.

Depending on the purpose of your question, you might get more practical answers by looking in gardening/landscaping sites.

The short answer is NO. A shadow is strictly due to the blocking of sunlight, so the shadow of 2 equally non-transparent (i.e., same density of leaves, both have similar trunk diameter, etc.) trees on the same hillside in the same weather conditions would not have different temperature shadows.
A plant's metabolism can and will affect the temperature surrounding the tree, but this affect is lost almost immediately as you move away from a tree. For example, in a study I did a few years ago measuring spruce tree temperatures (unpublished), we found that even within 5-10cm from the tree, the rise in ambient temperature was no longer measurable.
You're correct that the leaves of plants will absorb sunlight and as a result will increase in temperature. Walter Loomis's (1965) paper, Absorption of radiant energy by leaves (found here), suggests that leaf temperatures can raise to 30 $^\circ$C or more. However, he notes that their study found that even wind speeds of 5mph instantly cooled the leaves via conductive heat transfer. Our study with spruce trees also found this to be true. Transpiration will further help the tree rid itself of that increased temperature fairly quickly. Regardless of these facts, radiant energy from leaves in the canopy will not be felt how-ever many meters below within its shadow.
Finally, yes, transpiration can affect local climate, but this is only on the scale of whole forests. The transpiration of a single tree will likely not impact the ambient temperature around itself in any measurable way, especially at any distance greater than that I've already mentioned.


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What's the meaning of 'plasma' in 'plasma membrane'?
I wonder why is it called plasma membrane - what's the biological meaning of the word 'plasma'?

Plasma comes from the greek word which means something created or forged

I thought it was a no-brainer, apparently it's more of a historical journey into the origins of Botany. But I have a hypothesis: During the debate of whether the cell or the fluid within it was the origin of life, that fluid was called 'protoplasm' - first formed, i.e. it's the origin of life. The plasma membrane, then, is simply that which surrounds the 'plasma' - the protoplasm.

If you wanted the etymology of the word, would better have gone to english.stackexchange.com. Also, note that in etymology, there is a large disparity between what hypothesis sounds logical to a layperson and what hypothesis is true.


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Jamaican/Caribbean insect, plant identification keys/field guides
Where can I find plant and insect identification keys and Field guides for Jamaica specifically, or for the Caribbean as a whole?
I've searched Amazon and google for Jamaican and Caribbean identification keys/field guides, to no avail. I'm taking pictures of organisms in my backyard, and I want to identify them and post them to iNaturalist. For my own sake I want to be able to identify them myself, prior to and independent of the (long) wait for a community ID to be given and confirmed.

I've never been to nor botanized Jamaica or the Caribbean, but a quick Google search turned up the following references for Jamaican plants:

Iremonger, S., 2002. Guide to the Plants in the Blue Mountains of Jamaica. University of West Indies Press, 280p. ISBN: 9789766400316
Fawcett, W. and A. B. Rendle. 1910. Flora of Jamaica, containing Descriptions of the Flowering Plants known from the island. Longmans & Company. Found here.

You can also find a list of Jamaican species on Wikipedia and a list of medicinal plants in Jamaica here.

I've never seen "botany" in verb form as botanize/botanized; I like it.

@Bryan apparently you didn't like it enough to upvote :p. But yeah, "botanize" is quite commonly used among plant folks. I never really thought it strange, but I guess if you consider ornithize (we usually say "birding") or herpatize ("herp hunting"?) which aren't commonly used, it does seem kind of odd 0.o


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Why do floaters in the human eye appear to have a squiggly-line, tubular shape?
If you intentionally try not to tune out visual floaters in the eye, you can see them very clearly and they seem to have a squiggly line shape but with a volumous tubular look. Why is this?
They almost look like some kind of microbe as seen through a microscope, but that seems like a naive guess, and I'm curious to know the scientific explanation of why these entities look the way they do.

Eye floaters are usually small flecks of collagen floating inside of your eye (the same substance that is present in the extra-cellular matrix) and as you age they can clump together and cast shadows on your retina.
They may look like microbes to you because the clumping gives the appearance of a thread-like or rod shape, commonly associated with microbes. The light falling on the eye will enhance this by making them look transparent and somewhat like microbes. But rest assured they aren't, because if they are, then you certainly have superhuman eyes!


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Accumulation of Na⁺ and Ca²⁺ in the myocardiocytes while having acute heart failure
Why is it necessary to have accumulation of sodium and calcium ions in the myocardium cells while having acute heart failure? Normally, at resting membrane potential, sodium and calcium are more outside of the cell than inside, then I expect to see them enter less to the cell than to expect from them to enter and not exit.

Maintenance of resting membrane potential is an active process and you need energy and intact cellular membrane, otherwise the ions will flow in the direction of their electrochemical gradient, in this case into the cell.

Thank you^ Basically, If I understood you properly, you've said that in this case the cellular membrane is non-intact or damaged. How the non-intact cellular membrane is expressed in this case?

I meant to ask also How the non-intact cellular membrane is expressed in this case? and why it happens in heart failure? I thought about MI, but maybe it's not necessary.

@UbiquitousStudent the condition is energy and intact membrane, Since the word and is used it is understandable that violation of any one term, there will be failure.


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What does the word "refractory" in "refractory period" refer to?
What does the word "refractory" in "refractory period" refer to?
I know what it means "refractory period" (both, absolute and relative) in the action potential graph, but I don't understand what the meaning of "refractory" in this context is. What is it refractory for?

Probably I found the answer in Britannica:

"After repolarization there is a period during which a second action potential cannot be initiated, no matter how large a stimulus current is applied to the neuron. This is called the absolute refractory period, and it is followed by a relative refractory period, during which another action potential can be generated, but only by a greater stimulus current than that originally needed. This period is followed by the return of the neuronal properties to the threshold levels originally required for the initiation of action potentials."

https://www.britannica.com/science/nervous-system/The-neuronal-membrane#ref606386

That is excellent searching. It's great that your question was answered relatively shortly after you postd it. We like and expect that all users will try to answer their own question before they post, so kudos to you.

Thank you:) Actually as usual I searched about my question and I even saw the quotation before, but just later I got the relation between the "refractory" to the things that's written there, though it is not written clearly that this is why they are called "refractory".

@UbiquitousStudent You can post your comment as an actual answer to your question and select it as the best answer by clicking on the checkmark. This closes the question and also makes it easier for the community to know the answer.

Ok, I'll do that.

From encyclopedia Britannica:

"After repolarization there is a period during which a second action
  potential cannot be initiated, no matter how large a stimulus current
  is applied to the neuron. This is called the absolute refractory
  period, and it is followed by a relative refractory period, during
  which another action potential can be generated, but only by a greater
  stimulus current than that originally needed. This period is followed
  by the return of the neuronal properties to the threshold levels
  originally required for the initiation of action potentials."

Absolute refractory period = initiation impossible absolutely
Relative refractory period = initiation possible but in greater energy relative to the original required.


text:
Insect ID, Maharashtra, India
could someone please identify this insect? This photograph was taken in the Western Ghats of Maharashtra, India, near the town of Mahabaleshwar. Hemiptera was about as far as I could get using other online guides.
Thanks!

This is a Coleoptera (beetle), not a Hemiptera (true bug). The tarsal formula and overall shape to me suggests Meloidae.

Due to its coloration, shape and tarsal formula (5-5-4) I think that a Meloidae(Blister beetle) of the Pyrota genus is likely. You can see several examples of species in this genus from a basic google search. Meloidae has about 2500 species world-wide though, and there might be similar species in other genera. Here is an example of Pyrota bilineata, just for comparison.

(picture from http://bugguide.net/node/view/918423/bgpage)
You probably need somebody more knowledgeable on Indian beetles for a proper species determination though, but hopefully my suggestions can serve as a starting point.

Thank you! That looks very similar to the one in my photograph! Could the difference in the colour of the thorax and legs be attributed to gender or maturity?

@user19271 I don't think that your species is the same as the one in the picture I attached (P. bilineata) - the shape of the head and the thorax coloration is completely different. I only included it to show that your beetle is similar to the Pyrota genus.

@user19271 So, for the record, I don't think my answer should be "accepted", since it doesn't include a likely species ID.

@fileunderwater Often, ID to species level is impossible with insects, even by experts, certainly based on only photographs. So why shouldn't the answer not be accepted?


text:
Is the blastocyst a coeloblastula?
A coeloblastula is that type of blastula which has a fluid-filled cavity. Since the blastocyst of mammals has a fluid-filled cavity too, can it be called a coeloblastula? My book however mentions the two as different, and it gives the frog as an example of animals having the coeloblastula and mammals as an example of having the blastocyst.

What book are your using? Can you post a quote?

This is a bit tricky.
The blastocoel in e.g. amphibians separates ectoderm from endoderm and prevents cells of the blastocoel roof from inductive influence of vegetal cells. If you cut out the marginal zone and squish the roof onto vegetal cells, you will end up with mesoderm only:

Blastocoel is not homologous to blastocystic cavity. One could consider a tiny space between epiblast and hypoblast during gastrulation as a homologue of blastocoel, this however does not appear in mice. Blastocystic cavity forms at 32-cell stage thanks to Na+/K+ pumps as well as aquaporins. The inner cell mass is a mixture of cells expressing Gata6 and Nanog, which will form hypoblast and epiblast respectively.
But worry not, many people still call that cavity a blastocoel, in fact, I've seen it happen on Wikipedia. Anyway, I'd still recommend using separate terms for coeloblastula and blastocyst due to the non-homologous nature of blastocystic cavity and the blastocoel.

My sources:

https://kjcscientific.wordpress.com/project-excalibur/
Gilbert's Developmental Biology
Ćwiczenia z Biologii Rozwoju Zwierząt [Marek Maleszewski et al., University of Warsaw, Polish language publication]


text:
Why cooked food considered nutritious if proteins decompose at much lower temperatures?
Food is cooked/baked at temperatures that are significantly higher than what's considered normal for proteins/amino acids (40°C). Why is it, then, that such food is still considered nutritious after cooking? (meat, cheesecake, lentils, quinoa, mushrooms, etc.)

Where are you getting the 40°C temperature from? Denaturation of most proteins happens at higher temperatures than that. And what do you mean by decompose?

@MadScientist, maybe it's just bad memory. Can you share a source that gives some numbers?

Cooking is just a form of digestion.

What is digestion?

Digestion is the process of breaking down big molecules into smaller molecules. When you cook food you break down big molecules into its small components.

Why do we digest food?

Think about a long sequence of DNA for example. You eat corn and you have in your body a long sequence of corn DNA. What can you do with that long molecule....well, nothing. You need to break this long molecule down in order to be able to assimilate the constitutive nutrients. With those nutrients, you can now make up your own DNA. In other words, we need to break the big Lego castle that is food to get the building blocks in order to rebuild a spaceship. Digestion refer to the first process (breaking up the Lego castle). We refer to the part of the metabolism who breaks things down as catabolism and we refer to the part of metabolism that build things up as anabolism. Note that catabolism + anabolism = metabolism.

Why do we cook then instead of digesting by ourself

Digestion takes much energy and require the organism to have the right organs and to have the right matter (enzymes and stuff). We can save up energy (and the other stuff) by digesting the food outside our body. One could say that humans, (just like spiders for example) are performing external digestion.

Why cooked food considered nutritious

Cooked food don't have more nutrients than raw food. It is actually likely that in the process of cooking you would lose some nutrients going in the water that you throw away typically.
The big difference is that nutrients in cooked food are easy to assimilate which might end up being more healthy depending on the specific food source. Cooking may also destroy potentially toxic products.
Note that in response to the cooking behaviour, human gut has evolved to be shorter than it was in our ancestor.

then why are we advised to consume most vegetables raw?

@Sparkler according to this article, it's actually healthier to cook a lot of veggies. It actually breaks things down within the vegetables that our bodies might not be able to do.


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What predates on cactus in the Atacama desert?
Introduction
Last week, I was in the Atacama desert where I've seen many cacti. Some / many of them were seemingly suffering from predation. Most of predation seemed to be on cardón, often restricted (but not only) at the interface between the woody bottom part and the green spiny part. It looks like a big piece (maybe over 300 $\text{cm}^2$) of the flesh was bitten away. Unfortunately, I do not have a picture.
These cacti have very long spines and it was unclear to me what predator could maintain selection for cactus lineages to produce that many large spines.
In the desert, I have seen rabbits, guanacos, small birds, vultures, large black coleoptera and butterflies.
Question
In the Atacama region,

What species predate on cacti?
Is there a single species that causes most of the predation on cacti?

What does it look like? Are there pieces bitten/picked out, scratches?

In North America, bighorn sheep are known to eat Ferocactus sp (barrel cactus) by "pawing and butting at the cactus" (according to Warrick and Krausman, 1989). Were there any animals around that could do that?

Guanacos probably! I just had a hard time to imagine so few guanacos making so much damage to so many cacti. Also it was surprising to me that guanacos could deal with those spines but I guess that if bighorn sheep can, why guanacos could not!

I agree with @Remi.b. I would just also note that I have seen similar damage on candelabra (Browningia sp.) in northern Chile, where an apparently similar-sized wound was effected by perching raptors (scarred by talons). I am pretty sure that one of them was a variable hawk and another a mountain caracara. Also, you likely saw vizcachas, not rabbits!

Short answer
This type of herbivory is probably from feral livestock, especially donkeys.
Long Answer
There is video footage of guanacos eating flowers off of cacti in the Atacama. For example, an image capture of a Getty Images video:

 Credit: BBC Natural History
This type of florivory has been documented in related species of cacti as well (e.g., see Gomes et al. (2016)1)
However, I could find little evidence about guanacos eating the trunk of these cacti (especially to the degree you describe).
Actual herbivory of Echinopsis cacti has been reported in multiple publications. For example, Peco et al. (2011)2 cite feral livestock as a major source of herbivory in columnar cacti in South America:

Columnar cacti are an important feature of the arid “cardonal” landscape in South America. The predominant columnar cactus in the southern zone is Echinopsis (=Trichocereus) terscheckii. At some sites, the species suffers considerable trunk damage, attributed in previous studies to feral livestock grazing (donkey and cattle).
In a previous study we found that damage intensity on Echinopsis terscheckii trunks correlated with abundance of livestock dung in their surroundings, but not with the abundance of guanaco dung (Lama guanicoe) (Malo et al., 2011; Novillo and Ojeda, 2008). Futhermore, E. terscheckii was found in summer or winter donkey diet but not in guanaco diet in the study area (Reus pers. comm.). Direct observation of donkeys feeding on columnar cacti suggests that this species is the main cause of stem damage

See this National geographic video explaining how camels and other related animals handle eating spiney cacti. (Specifically, they accomplish eating cacti through the use of hardened papillae guiding the spines down the throat vertically).

Works Cited:

 Gomes, V.G.N., Koroiva, R. and Araujo, A.C., 2016. Vertebrate florivory on the short-columnar cactus Echinopsis rhodotricha K. Schum. in the Brazilian Chaco. Plant Ecology, 217(12), pp.1481-1487.

 Peco, B., Borghi, C.E., Malo, J.E., Acebes, P., Almirón, M. and Campos, C.M., 2011. Effects of bark damage by feral herbivores on columnar cactus Echinopsis (= Trichocereus) terscheckii reproductive output. Journal of arid environments, 75(11), pp.981-985.


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What animal / bird can be heard in this evening sound recording from Western Washington, USA?
We heard this animal outside in Western Washington (Port Townsend area) during the late evening. I think it is a bird, but it honestly sounds sort of like some creepy woman singing or something. The audio is linked below. The sound (in the audio) was repeated for a long time at random intervals averaging probably every ten seconds.
https://clyp.it/tzybty1w
Anyone know for certain?

That is the only sound clip I have...

I asked the same question on another forum here: http://www.birdforum.net/showthread.php?p=3454684.
It looks like another possibility is a barred owl. It also sounds somewhat similar.

My guess is an owl, possibly a great horned owl, which are found in the area and can sound similar.
Alternatively, it could be a mourning dove, which sounds similar again, and is common throughout the USA.

Not a mourning dove; pattern wrong.  Owl is highly likely; Barred Owl suggested in other answer is better fit than Great Horned. Compare at Cornell site:allaboutbirds.org

@mgkrebbs I agree.

This does sound like the characteristic "who cooks for you" call of a distant barred owl (Strix varia). You can hear this call at All About Birds run by Cornell Ornithology Lab.

The recording by
Andrew Spencer is most similar to yours given the distance it was recorded (though, he suggests it's a subspecies out of range that was recorded).

You might also try Audobon's sound clips as they were recorded at farther distance than those at Cornell and so better represent what you're hearing.

You're in range of these owls in Port Townsend:

 Source: All About Birds

No question ; barred owl. There are a few in the subdivision and presently I hear them fairly often. I think it may be fledging practicing the call. I am in  E TX at the southern end of the range on the shown map.

It could be the Sri Lankan spot-bellied eagle-owl lost in America.
Link = [https://www.google.com/search?q=spot-bellied+eagle-owl&oq=spot-bellied+eagle-owl&aqs=chrome..69i57j46j0i22i30l7.931j0j7&sourceid=chrome&ie=UTF-8][1]

Welcome to the site!  It would be much better to embed the image in your post; the google query will change over time.  Please [edit] in the picture.  Thanks!

Given the similarity of the call to a bird known to live in the area this seems at best extremely speculative. You are also more likely to get a positive response if you explain why your identification is correct. Specifically, please [edit] your answer to add discussion of key features that led you to this conclusion and supporting references or at least validated calls. Without this your answer is indistinguishable from opinion and thus off-topic. ——— Please take the [tour] and then consult the [help] pages for additional advice on [Answer] effectively on this site. Thank you!


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Find the concentration of free receptors in a solution of 90% free ligand and 10% receptor-ligand complex, knowing only the value of kD
I could use some guidance on how to utilise the equation for the disassociation constant kD to find the concentration of free receptors [R] in a solution containing 90% free ligand [L], and 10% bound [RL] complex.
The Kd of the receptor-ligand interaction = 10^-8 mol l-1
Where Kd =  ([R][L])/([RL])
I assume as a percentage I could state, [L] = 0.9 and [RL] = 0.1, but am not sure if I'm taking the right approach.
Any clarification on this would be appreciated.

there is a policy for homework-like questions, please read it before publishing question http://biology.stackexchange.com/help/homework

One big thing you're missing is units: Concentrations here must have concentration units - they can't be dimensionless numbers or percentages.
So one of the things you need to figure out is how to convert the percentages into concentration units. In this case, it's difficult to do directly, but we can apply a bit of algebra to figure it out. We're talking about 90% and 10% of the ligand in different forms, but we don't know anything about the total amount of ligand - that's alright, we'll just represent the total concentration of the ligand as $\ce{x mol \cdot l^{-1}}$. Therefore, we can now state that:
$$ \ce{ [L] = (0.9x) mol \cdot l^{-1}}$$
$$ \ce{ [RL] = (0.1x) mol \cdot l^{-1}}$$
Now the other bit of information we have is the equation for Kd:
$$\ce{ K_d = \frac{[R][L]}{[RL]} }$$
So we're looking for $\ce{[R]}$ (with associated concentration units!), and we know $\ce{ K_d }$, $\ce{[L]}$ and $\ce{[RL]}$ - or at least up to the unknown of $\ce{x}$. But, if you substitute the values you do know (including the factor of $\ce{x}$) into the equation and do some algebraic manipulation, I believe you'll find it doesn't actually matter what the value of $\ce{x}$ is - it should cancel out.
Note: If the value of $\ce{x}$ doesn't matter, why did I bother with the whole rigmarole of including it? Why didn't I just substitute 0.9 and 0.1 directly?
Well, the answer to that is my lead sentence - the concentrations in the equation should have (compatible) concentration units. If you don't have concentrations, you're using the equations incorrectly. (Look into the concept of dimensional analysis for a valuable way to help make sure you're doing many (but not all) calculations like this correctly.)
While for this specific problem things worked out nicely if you substitute the fractions/percentages directly, that's not a general solution. Depending on the exact setup of the problem, the $\ce{x}$s may or may not cancel cleanly. You may have to use some other equation/knowledge to put additional constraints on the value of $\ce{x}$. The only way to know that is to properly account for them from the start.

According to the information you have provided isn't the starting equation:
1 x 10EE-8 = (0.9 x [R]) / 0.1
So you can solve for [R]?
[R] = (1 x 10EE-8 x 0.1) / 0.9
I am not saying this is correct, but by substituting the values you provided isn't this how one would algebraically solve for an unknown? Maybe I am missing something(?)
You state you wish to know the concentration of free receptor. Wouldn't you need to know the total number of moles of receptor present in the equilibrium binding reaction, and wouldn't you need to know the final volume of the reaction?

Thanks for the input, I must admit I'm total perplexed by the question, and I agree there seems to be some data missing to solve but thats the info that's been provided. I hoped someone might have come across something similar.


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Identifying fish or shark jaw bone
I found this on the beach of coastal southern Maine in early March. The teeth are not a single row and lighter is for size comparison


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Volumes of the four heart chambers
We know that the left ventricle which feeds blood into the aorta is typically the largest chamber of the heart.
I'm looking for the typical absolute and relative sizes of the four heart chambers.

Welcome to Biology StackExchange! It is expected that you do some researching on your own prior to posting the question. For example, have you tried the simple method of Googling your question? It gives you the answer right away.

which species are you after?

It's tagged human anatomy.

@Domen, That doesn't tell me because ml/m2 is not a measure of volume.

@David, the values are corrected for the person's height, so that the volumes are divided by $\rm height^2$. See for example Fuchs, A. Normal values of left ventricular mass ... (2016).

@Domen, That requires further explanation, because why per height² and not per height or height³ which would be volume, which I might assume the heart volume scales with.

@David, we cannot discuss this in the comments. Please read the guidelines on How to Ask a Question on StackExchange. Then edit your question accordingly, and someone will be able to write a good answer.

From an echocardiographic perspective I direct you to the consensus statements in our field (1). Keep in mind echocardiographic measurements are generally considered less anatomically accurate compared to cardiac MRI or cardiac CT. Since you have asked for absolute and relative sizes I have mainly just included measurement indexed to BSA from which you can determine the absolute depending on the persons height and weight:
Page 7. Normal LV EDV (2-SD range):
62-150mL (Male), 46-106mL (Female)
P.39.e8 Normal ranges and severity partition cutoffs

Page 10. Normal LA volume range (indexed to BSA):
16-34mL/m2 (Male), 16-34mL/m2 (Female)
Page 20. Normal RV EDV range (indexed to BSA):
35-87mL/m2 (Male), 32-74mL/m2 (Female)
Page 30. RA volume (indexed to BSA):
25±7mL/m2 (Male), 21±6mL/m2 (Female)
References:

Lang et al. 2015 "Recommendations for Cardiac Chamber Quantification in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular imaging" Journal of the American Society of Echocardiography.

The volume is not the same in all the organisms having four chambered heart. But if you are talking about humans, here are the measurements:
The mean volume of the right atrium (RAMV), right ventricle (RVMV), and left atrium (LAMV) was 22.3 +/- 6.5, 40.3 +/- 6.5 and 28.7 +/- 8.2 ml/m2, respectively.
Source: Measurement of four chambers' volumes and ventricular masses by cardiac CT examination

ml/m² is not a volume. What on earth is meant here?

It is Left Atrial End-Diastolic Volume Index. The unit ml/m² is used to define the size of the atrium with respect to the flow of blood.

ml/m2 is an indexed volume.


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Flow of left ventricle into the aorta
I am currently practising for an exam and am having trouble understanding one of the exam questions:
The table gives the blood flow rate in various parts of the fetal circulation.
Flow rate in mL min-1 kg-1 bodyweight
Superior vena cava 78
Inferior vena cava 182
Right ventricle 169
Pulmonary veins (together) 13
How many millilitres of blood flow each minute from the left ventricle directly into the aorta
of an unborn baby weighing 3 kilograms?
A 91
B 104
C 156
D 273
E 312
Apparently, the correct answer is E and I can't explain why. My first guess was 3kg*13 for the pulmonary veins, since as I understand, all the blood in the left ventricle comes from them. However, this is apparently wrong.
Looking at the answer, I guessed around a little and the one way I found to get the number 312 would be to subtract the blood level in the superior vena cava from that in the inferior vena cava. Why, I have no idea.
If someone could explain to me why 312 is the correct answer and how this works, I would be very grateful.
Thank you!

Hint: draw the circulation with all the fetal shunts in place, and use the numbers given to map out how much must travel through each valve or shunt keeping in mind that it's a closed system so the amount of blood entering a compartment must equal the amount leaving.

Good question. One factor you need to consider is that pulmonary blood flow is low in the fetus, considering the lungs aren't oxygenating anything, but increases as it approaches 40 weeks. Still, at 40 weeks, pulmonary veins only account for up to ~ 25% of left ventricular output. There is also the issue of the two patents/cies: the patent ductus arteriosus and the patent foramen ovale. The majority of blood flow into the fetal LV is from the umbilical vein. What does the umbilical vein empty into? How do the patencies affect ventricular flow?

@BryanKrause - I was typing when you posted your comment, which is a more elegant exercise (and less loquatious) than mine.

Less loquaciously: You're calculation is based on neonatal blood flow (as opposed to fetal) with no loss from a PFO or PDA.

After the helpful comments, I have now been able to solve the question. Since some of the blood directly flows from the right to the left side of the heart in the foetus, the correct calculation would be:

Inferior vena cava + superior vena cava ; This calculates the amount of blood arriving in the right side

Subtract the amount in the right ventricle; The result is the amount that passes to the left side

Add the blood coming from the pulmonary veins; since they are also flowing into the left side, this gives the total amount of blood in the left ventricle

Multiply by 3 for the 3kg


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What caused these shallow depressions in a European forest?
Recently, in an eastern European forest, I came across many depressions in the ground of a regular round shape, with a flat bottom and vertical walls.
Many were filled with water.
Some were obviously dug recently.
At the same time, there were no traces of excavated soil nearby.
I have no idea what kind of creature could do this, and why.
Has anyone come across something like this?
What it is?

Welcome to the site. Where in the world were these photos taken? - I'm guessing Eastern Europe from your name. Could be soil sampling for a science study.

@bob1 yes, you're right, it's Eastern Europe

Another, more cynical, suggestion - any rare/valuable/collectable plants in the area?

Or elephants? ;p

@bob1, "Another, more cynical, suggestion - any rare/valuable/collectable plants in the area?" I did not see anything like it there, although I looked carefully enough, because I picked mushrooms.
besides, it is unlikely that the correct shape of the pits will be important for thieves

Could be that something was burried there... I like to dig out historical artefacts (others call it junk :D) and those holes made me think of when I dig out an old pot or something like that, that is laying in the ground.

@nika I agree, though there most people would leave the soil behind and perhaps pile it to the side, which we don't see here. This was why I was suggesting perhaps plant collectors or someone doing a soil survey.

@nika I did not specify the number of artifacts. there were about a hundred of them, or more. many could simply not visible, because the grass was overgrown.
this is a young forest on the territory of an abandoned boarding house, so the presence of antiquities in the soil is very unlikely.

It looks like a horse hoof print in soggy ground.


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Cellulase-producing plants, in any phase of their growth, in similar amounts to amylase in other plants
Daikons and barley sprouts are able to make amylase. What similar cases exist where plants may create cellulase in similar amounts?

Seedlings of many species produce amylases to convert starches in the endosperm to usable sugars. I'm not aware of any plants that produce cellulase in amounts sufficient to break down large amounts of cellulose. But see Do plants have cellulases? and the article linked in the comments for discussion of the role of cellulases in cellulose microfibril formation in plants.


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Identifying a bug
I found this bug ( vary in size )after deep cleaning to my bedroom today exactly in my bed sheets and window sill and my desk , can someone help me identify them

Please provide your location as well as size and preferably higher quality images of your specimens. Thanks.

These are two different species of true bugs (Heteroptera).
One of their unique characteristics which distinguish them from other insect groups are their forewings (the so-called "hemielytron", for a detailed figure see here) which are hardened at the base (~ 2/3, in red) and membranous at the tips (~ 1/3, in blue) and folded flat over the abdomen when at rest.
Assuming, these photos were taken somewhere in the Palaearctis (North America, Europe or Asia), I suspect

to the left is a birch bug (id characteristics from this photo: mostly translucent forewings, elongated and red-brown head, yellow-brownish body, relatively large eyes, last antenna segment club-shaped) and
to the right a member of the genus Stenodema (id characteristics from this photo: yellow-brown and elongated-oval body, large scutellum, long antenna and legs), relatively small eyes; Stenodema species camouflage themselves as grass grains on which they feed on).

Both species feed on plants (mostly birches, but also other wooden plants and grasses, respectively) and moved into your apartment accidentally.

Good answer, but it could be improved by providing information on why you think these are the correct identifications.

Thank you for your feedback. I added some more details on how I id'ed these species...

Excellent answer now!


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Bug Identification: Black Insect with Red/Orange dot on back
I lifted the cover off my push bike today and discovered 15-20 of these insects all along one of my brake cables.
A few were tending to "egg" like structures that were stuck to the cable and stood out (I've since wiped these away).
I've never seen these before and haven't had much luck Googling or reverse image searching.
They have black "ant" like bodies with orange/red dots on their back. The same orange/red is present on the tips of their "feelers".

Video of one walking down my tyre; https://i.sstatic.net/LTm5b.jpg
This was in Queensland, Australia.

It's difficult to judge scale from the pictures, could you give us some rough idea of size at all?

@ARogueAnt. it was about the same size as a large ant.

Possibly young harlequin bugs.

The narrow black body, long bent legs, red abdomen, and red-tinted antennae all make me think this is the nymph of a hemipteran called an assassin bug (Family Reduviidae).
The nymph of the Bee Killer Assassin Bug (Pristhesancus plagipennis) looks similar to yours and is found in Queensland. [Source: Queensland Museum]

 Source: Queensland Museum

This is definitely what I saw! Thanks!


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Sickle cell life span
How long do sickle red blood cells "live" before being broken down in phagocytosis?
I had trouble doing a normal search as it brings up life span of those inflicted with the disease. Also, I have been doing a semester long assignment, where we are delving into all aspects of this disease, and I have 20 sources so far and still haven't come across the answer.

Try changing the order of the words. :) lifespan of rbcs in sickle cell anemia

A better title would be "Lifespan of sickle cells" (fewer words and no abbreviations). I'd change it myself, but am voting to close as there is no indication of which of the many sources on sickle cell anaemia the poster was unable to find the information in.

Hi Brittt,. welcome to Bio.SE. Please share a few of the sources you've already read to indicate to the community that you've done your own prior research. This will likely stave off a full close vote.

Sickle cells usually die after about 10 to 20 days, compared to normal red blood cells, which live an average of 120 days. The bone marrow can't make new red blood cells fast enough to replace all the dying ones which causes anemia,low blood count that results in fatigue,shortness of breath and related symptoms.As the cells are made normally but die too rapidly,this is termed as haemolytic.

Welcome to Biology SE! Although this could potentially answer the question we prefer to have answers backed up by references. Un-referenced answers may be challenged or flagged for deletion.


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Is this a bed bug or some other bug?
This white/yellowish bugs are crawling over my walls under cracks and below my wardrobe. I am not sure if they are bed bugs or some other bugs, there are very small in size thus I zoomed very much on the photograph, I hope someone would be able to assist me on identifying the bug.!

This isn't a bed bug (see this page for the genuine article); I'm sure it's a book louse, but can't go further than that without a better picture; you should probably add the "entomology" tag to your question as well.

@ArthurJFrost I agree. It is a psocopteran. I am guessing that the post is more about worrying if it is a bedbug than precise identification. You should post your answer. : )

definitely a psocopteran. Not a bed bug.


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What is the role of CRISPR-dCas9 in gRNA-dCas9 transcription regulator complexes?
In this paper1, I read that mutant versions of Cas proteins such as a deactivated Cas9 (dCas9) are used alongside a guide-RNA (gRNA) to form variants of CRISPR tool that can function as transcription regulators.
Since the mutant Cas9 has lost its nuclease functionality, the mutant gRNA-dCas9 complex can "block" transcription factors such as RNA polymerase from binding a certain gene, hence repressing transcription or elongation.
Another way that dCas9 can regulate transcription is by "carrying" another transcription factor - be it an activator or repressor - and this can be done by engineering a dCas9 fused to the other transcription factor of choice.
I understand how the dCas9 can block the binding of another transcription factor to repress transcription initiation or elongation, but what is the point of fusing another transcription factor with the dCas9? It seems to me that in this scenario, the dCas9 is just a passive carrier of the transcription factor that is actually doing the job, so why can't the transcription factor be fused with the gRNA instead, so that it can directly affect transcription when the gRNA forms complimentary base pairs with the target gene, instead of it being on a passive dCas9?
 1. Jusiak, B., Cleto, S., Perez-Pinera, P. and Lu, T.K., 2016. Engineering synthetic gene circuits in living cells with CRISPR technology. Trends in biotechnology, 34(7), pp.535-547.

so why can't the transcription factor be fused with the gRNA instead,
  so that it can directly affect transcription when the gRNA forms
  complimentary base pairs with the target gene, instead of it being on
  a passive dCas9?

The main reason for that is that both the gRNA and the dCas9-TF (transcription factor) combination can (each) be encoded genetically, while a combination of a gRNA with a transcription factor could only be generated chemically.
The possibility to genetically encode the dCas9-TF + gRNA unit allows one to:
a) use established methods for transferring DNA into cells,so that the cells make the Cas9 and the gRNA by themselves and
b) generate cells that will stably express the whole unit (dCas9-TF + gRNA) forever.
Neither of these options would be possible with a chemically linked gRNA-TF (which is also much harder to make for molecular biology labs that don't have the proper chemistry equipment).

Thank you. So in a more general scenario, is it more conventional to induce the synthesis of a gRNA-Cas9 complex by the cell itself, rather than deliver the already-synthesized complex into the cell?

I don't really have experience with Crispr/Cas9 myself, so I'm can't say for sure, but its is definitely easier to only transfer DNA (plasmids) in cells and let them build the proteins & RNA, since DNA transfection is one of the most common molecular biology methods. Transfection with protein &/ RNA is harder and therefore more unconventional (but still sometimes used for Cas9, especially if you DON'T want the cell to retain the Cas9 protein in any way)


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What is the difference between scale vs cataphyll?
What is the difference between scale and cataphyll in botany - aren't these the same type of organ?
E.g. do cycad cones have scales or cataphylls? Pine cones have scales, I understand the compound nature of pine cones - does that make them scales?
On fern petioles/stipes there are often scale-like organs I've seen called scales (though they are not very scale-like).

Welcome to Biology.SE! What research have you done before asking it here?

According to "Plant Identification Terminology: An Illustrated Glossary" (Harris & Harris, 2001):
Scale:

Any thin, flat, scarious structure

Note: "Scarious" = Thin, dry, and membranous in texture; not green

Cataphyll:

Brown or colorless scale-like structures believed to be modified leaves

So "scale" is going to be used more broadly, while a "cataphyll" (though scale-like) is more specifically always some type of modified leaf.
According to Wikipedia:

Cataphylls include bracts, bracteoles, and bud scales, as well as any small leaves that resemble scales, which are known as scale leaves.

You can find good illustrations of cataphyll examples here.

Thanks, I understand cataphylls a bit better. With scales, how does this definition fit in with scales on conifer cones? And do cycad cones have scales or are they just called sporophylls? I see in "Pterophytes and Gymnosperms" (Kramer and Green, 1990) they say cycads have 'scale-like sporophylls'. Why are they scale-like and not just scales?