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Could somebody please tell what tree genus is this?
Leaves of a tree in south Asia:
It is in Pakistan, found in flat land habitats.

South asia is a bit vague. Can you be a bit more precise and what kind of habitat you found it?

Please provide approximate size of leaves. also, if possible, providing additional images/descriptions of the plant is always helpful: closeups of leaves, images of flowers, plant growth size and habit, etc.


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Bug larvae identification
 anybody know what this might be, found in my bed. Pennsylvania, USA . Thanks

Please see the tag info for species-identification to learn how to make an answerable species-ID question.

That's a silverfish (order Zygentoma) https://bugguide.net/node/view/79 This individual is not in great shape, and probably got crushed, however you can see it had the cerci in its tail. The individual is lacking antennae, which are usually long, but the eyes  are also very characteristic. You can see a similar picture on this thread (https://bedbugger.com/forum/topic/here-we-go-againcame-home-now-and-found-this-id-please-silverfish. They are fairly common in homes and are harmless. They feed on fibers and detritus in your home.

that certainly doesn't look like any silverfish I've ever seen. Presence of prominent cerci is not conclusive evidence of a silverfish. The OP's specimen appears to be a larvae of some type, and silverfish don't have larvae as they undergo direct development vs. complete metamorphosis. Please provide stronger support for your answer. Thanks.

I stand by my ID, because I've seen exactly specimens of silverfish like that. This is just a mangled specimen, which makes sense because the OP found it on the bed. Also, I know silverfish have direct development (I'm a PhD in Entomology), but you're assuming the OP knows those finer biological details.

Ok please explicitly explain what characteristics (and /or provide image examples) you've used to make your claim. Currently, it comes across as an unsupported guess. Due to the immense amount of misinformation on the internet, Answers can't be based on expertise alone - you need to expand upon your answer. Regarding biological details, please see here. Thanks.

source: Stack Exchange

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sort: votes


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Could anyone please identify this Indian bug?
Photographed by a friend recently in central India. next to Panna Tiger Reserve.

Welcome to Biology.SE! Please edit your post to add an estimate for the size of this insect as that can be a helpful clue for identifications. ——— You may also want to take the [tour] and then go through the help pages starting with [Ask] questions effectively on this site. Thanks!

While I can't help with a specific identification, it looks to me to be some sort of immature true bug whose wings are still coming in.  That may help narrow down the possibilities.

Unfortunately I did not see it and there is only this one photo. Such amazing markings caught my eye. Was thinking assassin but could find no exact image. Thanks for trying.

@Joanna if you think my answer is right please select it as the answer. Also,@cowrie try narrowing down the species with the geographic location too, helps a lot:)

@Joanna please mark my answer as verified if you find it accurate

The species from the photo is almost definitely a Catamiarus brevipennis.

The bulged and striped abdomen
The non-striped legs
The unique pattern on the wings
The antenna thick at the beginning and becomes thinner towards the end.
The protonum also has a unique granular structure unique to Catamiarus brevipennis.

Source : India Biodiversity Portal

I suspect this is a hemipteran, an assasin bug. I think this because of the shape of the legs, the reduced elytra and the bulgy eyes. If you had a picture from the side which would show the profile of the mouthparts, and if they happened to be protruding in the shape of a stylet, i'd be more confident that it is a type of assasin bug. Its definitely trying to mimic some other insect - hope this helps!

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Valve-like layers example in nature?
I am searching for an example in the nature, where a layer of something (skin, coat, film etc) can allow fluid to flow trough (not absorb) from one direction and prevent/repel from other direction. I am not talking about vein valves, prefer more like a nano-structure of valves as a layer on/around something.
Update:
I found something similar what i am searching for, but its not clear:

Gap Junctions (animals)
Directly connects the cytoplasm of two cells, allowing various ions
  and molecules to pass freely between the cells.

And there is a reason why this channel is hydrophilic, someone can explain this?
About me I have no deep knowledge about biology, please be patient and help me to understand things on basic level. Thank You!

I think an answer that explains this question at your level of understanding might be too broad. The things you want to understand are cell membranes, concentration gradients, osmosis, channels for water and other ions, transporters for ions, etc. Someone might find a special example, but typically in biology, besides bulk transport, water is never moved by itself: instead, osmotic gradients pull water into particular spaces. Many plants, for example, collect water by pumping potassium into their roots: water follows this osmotic gradients.

Gap junctions don't have any "direction" to them: they are basically just open "holes" between cells that allow for diffusion depending on concentration/electrical gradients.

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Can you eat enough to make your stomach explode?
Background
After eating a large meal last night, I noticed that my tummy had significantly enlarged. After that, I started wondering if eating too much could cause a stomach to explode. Could this actually happen?
Question

Are you able to explode your stomach by eating too much? Can it pop or break?

I assume your body would just regurgitate the extra food.

What if you held in the regurgitation? Then would you explode?

It is obvious that you will make yourself to vomit... The human organisation isn't created by nature to be self-destroied.

Perhaps better suited to the Health S.E. site.
Eventually vomit will become projectile... You can't hold that in I don't believe.

Here's a simple cross-section of the stomach (from here):

The stomach accomplishes much of its function by mechanically breaking down the swallowed food particles and mixing them with acid and enzymes into a sort of slurry. To do this, there are three major layers of muscle surround the stomach - from the outside, the longitudinal layer, the circular layer, and the oblique layer. The stomach also has two holes in it - the gastroesophageal opening, coming from the esophagus with the swallowed food/saliva mix, and the pylorus, where the food/acid/enzyme slurry exits into the duodenum, which is the beginning of the small intestine.
Due to the three layers of (rather strong) muscle, the stomach doesn't have a lot of expansion capability once it is filled completely to capacity. Fortunately, this almost never occurs (despite how we may feel after a large meal) because material is always leaving the stomach on its way to enzymatic digestion in the intestines. Additionally, once the stomach is filled to a certain extent, hormones such as leptin are secreted that give you the feeling of being sated, or full, triggering the brain to make you stop eating.
Of course, as we can see with the current epidemic of obesity around the world, the stomach can change its size over time. However, this is a rather slow process (weeks to months to years) of adapting to continuously consuming large meals.
But what would happen if you completely ignored these internal warnings, or were being force-fed, or whatever? Instead of rupturing (the biological equivalent of "exploding"), food would most likely be expelled either into the small intestine or back into the esophagus and back up the way it came down, i.e. causing vomiting.
For this answer to be complete, however, I should point out that stomach or gastric rupture is technically possible, although it is an extremely rare occurrence. Cases have been described in the literature (1, 2, 3, etc.), but they are rarely correlated with overeating or eating disorders like bulemia. In cases that are, other pre-existing conditions such as gastric ulcer have been found on autopsy that likely weakened the stomach wall in the first place. The bottom line - if you're an otherwise healthy person, a single instance of massive binge eating is very unlikely to end in stomach rupture, as vomiting will most likely begin well before you are in significant physical danger.

Stomach rupture is a known rare cause of death in those with eating disorders

http://www.medicaldaily.com/breaking-point-when-does-eating-too-much-one-sitting-become-deadly-362856

@GrahamChiu it's incredibly rare, which is why I didn't mention it. I guess I will for completeness.

"Four reports of unexpected mortality due to gastric rupture and necrosis were found in 152 reported deaths, accounting for 3% of the causes of mortality. Four additional individuals were suspected to have gastric rupture. " in Pradi Willi syndrome .. 3% in at least this population is not incredibly rare as per your 3rd reference.

First of all, you must understand the way that our(human like) digestive system, simply digests the food. Here is some information about what happens when you eat:
Digestion is the process of changing food into a form that the body can absorb and use as energy or as the raw materials to repair and build new tissue. Digesting food is a two-part process that’s half mechanical, half chemical.
Mechanical digestion begins in your mouth as your teeth tear and grind food into small bits and pieces you can swallow without choking. The muscular walls of your esophagus, stomach, and intestines continue mechanical digestion, pushing the food along, churning and breaking it into smaller particles.

Chemical digestion occurs at every point in the digestive system, beginning when you see or smell food. These sensory events set off nerve impulses from your eyes and nose that trigger the release of enzymes and other substances that will eventually break down food to release the nutrients inside. The body then burns these nutrients for energy or uses them to build new tissues and body parts.

ALSO HERE ARE THE COORDINATES OF YOUR "TUMMY":
Your stomach, a wide, pouchy part of the digestive tube, is located on the left side of your body above your waist and behind your ribs.
Now, lets get to your main body of your question:
Like the walls of your esophagus, the walls of your stomach are strong and muscular. They contract with enough force to break food into ever smaller pieces as glands in the stomach walls release stomach juices — a highly technical term for a highly acidic blend of enzymes, hydrochloric acid (HCl), and mucus. The stomach juices begin the digestion of proteins and fats into their respective bodily building blocks — amino acids and fatty acids.Churned by the stomach walls and degraded by the stomach juices, what started as food — apples, pears, potato chips, steak, cake, you name it — is now a thick, soupy mass called chyme (from chymos, the Greek word for juice). The stomach’s wavelike contractions push this messy but still intact substance along to the small intestine where your body begins to pull out the nutrients it needs.
Moreover you should consider that the stomach is made from muscles; that makes it strong and immune to HCL. So, if even a very strong acid like HCL can do any damage to the stomach, will a very big meal make it to explode? Simply it will force yourself to vomit just because the very big ammounts of food can't be digested.

Oh, oh, I know how digestion happens. This is a hypophetical question. Isn't the stomach the actual sciency name of the actual stomach section, but the general area with the skin there is called the tummy?

@DanielCann "tummy" is not a scientific term by any stretch of the imagination. In American English, it's a childish name for the abdomen.

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unknown bird in Long Lake Michigan......chocolate brown head and neck, charcoal body and tail, ivory wings, top and bottom
light chocolate head and neck w/ charcoal body and tail. the wings are ivory white, top and bottom from the body outwards. the colors are clear.....not mixed with other colors. no stripes or spots, etc. slightly smaller than a robin.

Species identification questions should include a picture. It is otherwise very difficult to identify based solely on your verbal description.

Welcome to Biology.SE!  If you are unable to provide a picture it would help if you described anything else you observed.  Some examples are: behavior, calls, shape of wings, shape of beak, shape of tail, feet (webbed?) and overall body shape.

That's a very interesting set of colors.  Unfortunately nothing springs out at me, although I can think of a couple of birds that might sort of (maybe) match.
First, common pigeons come in all sorts of colors and patterns, and it's possible that yours is one.  On the other hand, common pigeons tend to be very familiar to most of us, so I don't think you'd be asking about that.
Second, there is a tern that is moving through the area about this time of year, that might fit:  Black Terns can have a lighter wing.
Here's a link and a representative photo:
 https://www.allaboutbirds.org/guide/Black_Tern/overview

There is another, even better possibility, if your bird is ternish:
The White-winged Tern (formerly White-winged Black Tern) is an uncommon late-summer wanderer through much of the region.  Here is a link and a representative photo:
https://avibirds.com/white-winged-tern/

Could it be any of these? These are all iNaturalist observations around the Long Lake, MI.


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DNA like marine animal or egg
What is the name of the marine egg or living being that is transparent like a jelly fish or a Venus girdle, with a shape like a DNA or better like a chain of infinites, long as half of a hand and large as half of a hand nail?

Imagine a DNA-like strand but with no internal "sticks", white-ish, 10 cm long and 2 cm wide

Alternatively, how do I narrow my research in order to find the name of what I saw underwater?
The image seems too simplified but I just saw something like that, pretty simple, essential and little.

Is there a way to upload an image here? I used a paste bin but in case I can upload it. ( link to pastebin: https://pasteboard.co/Iv4fT7W.png )

@AMDP You can [edit] your post and copy the image into the question editor or use the image uploader. See How to upload an image to a post?


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Can this toad be approx 1cm long?
Recently the toad from this video has been identified as an American Toad inside this post in Reddit. The original video mentions it was filmed in White Clay Creek State Park, Newark, Delaware, USA.

Calculating the water's wavelength based on the sound yielded a value of 0.5mm. Using the image's ratios, the toad's length can be estimated. The result was 7mm. Yes, a toad being 7mm long.
The purpose of this question is to ask both if it effectively is a species of American Toad and if it's plausible for it to be 7mm long.
Thanks

Welcome to Biology.SE! Identifications questions should include: 1) one or more clear closeup photos of the organism (photos from multiple angles if possible) — photos must be uploaded (not links) — e.g. post stills captured from the video; 2) habitat information. Please [edit] your post to include this essential information. ——— Please also take the [tour] and then go through the [help] pages starting with [Ask] questions effectively on this site. Thanks!


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Is this a bed bug? Found this on the pillow as I was putting my daughter to sleep
My husband found this small (~4mm long) insect on a pillow while putting my daughter to sleep in our New Jersey (USA) suburb home.
We checked our daughter's and our own mattress as well as the rug, but we found no mark or other bugs. No one has recorded any bites.
We had bedbugs years ago in another home in another city, but have not seen evidence previously in this home. We moved in about 2 months ago at the end of September. We have not travelled recently due to Covid.
We are petrified and will call someone first thing in the morning but need to know

Unfortunately, yes it looks like you've got a bedbug. See the linked post for more details. Good luck!!

Can it be the only one or does it mean my house is infested? We have no other sign and we checked thoroughly as we had an issues at another place years ago

you need to update ([edit]) your post with additional information for anyone to provide additional accurate information. Please provide the dimensions of your specimen (and a clearer photo would be ideal), your location (city, state/province, country), more information about the building you found the insect in (is this your home?, how long have you owned/rented it?, are you in a multi-home unit?, are you urban or rural?), and information about recent travel or having new materials come into the home (e.g., suitcases, clothes, bedding, etc.). thanks.

Size is important, by the way, because bed bugs must feed prior to every molt. So if your specimen is large enough to be classified as an adult, it would indicate this specific specimen has taken a blood meal multiple times. If you truly have found no evidence of bed bug bites and have found an adult, it suggests it hitched a ride into your home. However, this isn't full-proof, since some people have minimal reaction to bed bug bites so such blood meals may have in fact gone unnoticed. So please update with more info. also, see my linked post for additional useful links for what to do...

As is suggested by my comment above, it is possible to have a single individual hitch a ride into your home. However, a single bedbug could also lay up to 100+ eggs per month with initial broods of eggs hatching in 6-10 days. So even if only one came in, more could be present. Your situation is not clear. Again, the more info you provide, the better chance we can provide you detailed and accurate feedback. (If nothing else, be prepared to provide this information and more to an exterminator in the AM). Update the post if you'd like more feedback; otherwise I wish you good luck!!

We did not travel (covid ...) But we had contractlr

The size (4mm) is similar to a late-stage nymph (~4.5mm), but is likely too small to be an adult (5-9 mm). (see here for size ranges). Only adult females can lay eggs (see here and here for sexing tips). Their small (~1/10") white eggs are laid in clusters in mattresses, furniture, or in cracks in the wall, baseboard, or floorboards. (See here for more egg info).


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Why can hair grow without limit while eyebrow cannot?
I cut my eyebrow and it grows until reach a certain length. Hair can grow without limit.
Why can hair grow without limit while eyebrow cannot?

Do you know it can grow without limit, or have you just not let it grow long enough to find out what its limit is?

Hair actually does have a limit to its growth. All hair cycles between periods where it grows, and when a new stand appears, which pushes the older, long hair out. Hairs that are generally shorter, like eyebrows or arm hairs, have a shorter growth period before a new hair pushes the old one out. The hair on your head actually grows much faster than many other hairs as well, so with the longer cycle and the faster growth, it can grow to be much longer before being replaced.
I remember hearing that for many women (the cycle does vary from individual to individual, which explains why some men can't grow beards while others look like ZZ Top) the growth cycle ends between the waist and butt.
My speculation would be that hair on the head could grow for longer because there are more capillaries in the scalp, which might lead to more nutrients, higher cell turnover (like you see in dandruff), and hence more hair. That's just a guess, mind you.


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Identification of this spider?
I find these in forests in Oregon, western half, though they're probably on the eastern half as well. They live under pieces of wood and bark, and have a small web across the ground. Mine will eat crickets, but I think they eat carpenter ants, termites, and maybe pillbugs/sowbugs. It seems about an inch long, red on the thorax and legs, and dark grey and slightly hairy on the abdomen. The closest to this spider I've found is sowbug killers -- they're in my backyard, but they're smaller then this spider and also are a light tan on a hairless abdomen, with lighter colored legs. The fangs also seem different shapes but I'm not sure about that.

Thanks for getting the images up there, I still can't figure out how to do it. Is there a way on mobile?

There is on iPhone at least, I'm not sure on other platforms.  You can always type up the markup manually (though it is a little cumbersome on mobile): ![an image](http://example.com/image)

I thought it was the woodlouse spider too which is why I posted an answer but I am unsure now since you already suggested it. It should belong to the genus Dysdera though

Oregon has over 500 spiders so its hard to identify which one this is

This is very likely a species in the Amaurobiidae superfamily, and I agree appears to be Callobius severus (the hackled-band weaver or the hackledmesh weaver).

 Source: Bugguide.net

 Source: Kyron Basu 2012
Moldenke et al. 1987 provide a key to spiders of the Pacific Northwest. Importantly, they note:

adult genitalia are necessary for identifying species and separating
Callobius from Amaurobius.

For example, here is a picture of Amaurobius ferox (Hackledmesh Weaver)

 © Danny Steaven 2008

I've seen numerous sites conflate this species with C severus and actually I've seen sources that identify them both as the "Hackledmesh Weaver".

So although the OP's specimen strongly resembles Callobius severus, a scope is necessary to truly identify to species. This Penn State page provides good information regarding these similar looking species in the superfamily.

Callobius and Amaurobius species have similar life histories and behaviors. They are most often found in damp locations under bark, leaf litter, and stones, as well as in woodpiles and other protected areas.

Stephen Ellis Lew (2011)  produced an atlas to the genitalic morphology of the Callobius genus, and he proposed a morphological diagnosis that is more consistent with principles of homology than those previously in use. [See the link for his dissertation on the subject].
Callobius severus
Description:

Cephalothorax and legs = reddish to dark brown [Source].
Abdomen = dark to light grey with fine hairs; often with large, bilaterally mirrored paler spots.

Ecology:

Nesting woodland species commonly seen in the Pacific Northwest

McIver et al. (1990) suggests that this species of spider is one of many that is characteristic of young forests.

Is it Dangerous?:

Not according to this Penn state website:

The one verified record of a bite by an immature Callobius species resulted in pain, itching, swelling, redness, and nausea.

Vetter & Antonelli provide evidence for how to differentiate this species from the "more dangerous" hobo spider.

in the side view, the palp of Callobius males has large, conspicuous, pointed projections (Fig. 7).

It look like Callobius severus to me.

I agree with the above that the spider is probably Callobius severus, especially since you found the spider in a forest in Oregon.

The spider in found in parts of the United States and Canada with nests most widespread in the U.S. state of Washington and the states bordering Washington, making them most common in America's Pacific Northwest region.


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Insect identification - Oregon
Western Cascade forest, in a small clearing in the grasses. Possibly related to leafhoppers? Looks a little bit similar, and it was able to jump quite well. The last pair of legs are arranged the same exact way as leafhoppers. Assuming it's within Hemiptera. I've never seen one before.


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Can anyone identify these moths?
Here are two lepidopterans I collected in Oregon (USA). The wingspan of the bigger one (on the left) is ~4 cm. I spent a lot of time browsing this website hoping to find a match, but I didn't have success.

Out of interest, did you find these in the same place at the same time? They have fairly different phenologies...

@theforestecologist approximately at the same place and time. Time period 1 month, place - the same region of a town.

The one on the left is a Lunate Zale Moth (Zale lunata).
See Western Washington University's PNW moths page for more detailed info.

The one on the right is a Forage Looper Moth (Caenurgina erechtea).
See here for an image similar to the one in the question.
And again take a look at Western Washington University's PNW moths page for more detailed info.


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Comprehensive biology or anatomy wordbank
I teach A&P for bio non majors. I have a special needs student whose accommodation requires a word bank for any anatomy identification questions I have on the exam. I would like to present the student with a 'master wordbank' (presumably hundreds of words in length) that would act as a word bank for all the exams in the course. I'm surprised to be unable to find much of anything online. Has anyone seen something like this?

The index of your textbook?

I agree that your textbook's index or glossary is probably your best bet. Because anatomy can be taught at so many different levels (breadth and depth) and you're teaching at a fairly basic level, you'd have a hard time finding  a list elsewhere that emphasizes/includes what you want but doesn't weigh you down with terms your class does not cover

this textbook has no such thing unfortunately

I've been trying to find something similiar so far all I have found is an academic headword  list. https://www.victoria.ac.nz/lals/resources/academicwordlist/awl-headwords/Headwords-of-the-Academic-Word-List.pdf

So I found a good list. Behold: wikipedia:
https://en.wikipedia.org/wiki/Glossary_of_biology

If you are teaching A&P, then this list will definitely not have all possible terms. For example, there are no named muscles in this list (or at least the first 5 most obvious I searched for were not), which normally would be included in an A&P exam.

@kmm this is not A&P at harvard medical college. However, that's not good regarding the muscles. When i did some random testing I didn't cross check any of those.. do you remember a muscle you queried?

Look for "rectus", "biceps" and "femur". None is on that list.

@kmm To be fair they are not really headwords but specific terms for an individual object. If you want to include ALL of those you would be better off with the entire biological dictionary.

You may want to look at some biological terminologies or ontologies. These can be browsed online using portals like the OLS or Bioportal. You can restrict your search to particular domains or sources, such as the FMA for adult human anatomy and Uberon for general metazoan and comparative anatomy. This may be overkill for your purposes, as these ontologies are intended for computational applications rather than as an educational reference source. For example, terms are linked to other terms via different relationship types. However, this extra information may turn out to be useful, and the developers of these ontologies may be interested in helping with educational use cases (I am the developer of Uberon and this is something I am interested in).
If you wanted to extract a table of terms from one of these, perhaps restricted to a domain (e.g. human muscles) then this may be possible with a bit of work with some of the online interfaces, or it's something that could be done by someone with programmatic skills. Someone on bioinformatics.stackechange.com could help with that task. Many of these are available via open and unrestrictive licenses so there should be no legal issue here.


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Identify a large wasp (?) from southern Poland
This insect has appeared "out of nowhere" in one of my rooms. Can you help me identify it?

Details:

location: Katowice, Upper Silesia, southern Poland, eastern Europe (46.42 N, 17.78 E),
date: April 3rd, 2021 (early Spring, approx. 3:10 pm).

At first I was more than sure that this is large male bee / wasp / Apidae family member. But I was surprised to see absolutely no signs of yellow or orange strips, only gray ones, if I am not mistaken.
The windows were closed tightly at the moment of its appearance and were not open too many times in the days before, as we still have kind of cold early Spring here, in Poland right now. Though I must admit that we had a very warm previous weekend (March 27th/28th) with temperatures of up to 19°C / 66°F. But, I am still unsure, if it appeared just "these days", or if it was able (in some magical way) to survive somewhere behind wardrobe since past Autumn (very not likely?).
It was very weak at the moment of finding it. It was certainly unable to fly though its wings seemed OK. It was looking like it had at least one leg broken. He was moving very slowly and attaching itself to any surface it found (piece of paper, ruler etc.). I moved it gently to my balcony / piece of grass and let the nature do the rest.

it is not a wasp it is a bumblebee,i did see this years first bumblebee a coupe of hours ago here in norway,they do wake up now in the start of spring to start a new hive.i do not know what type you have there but it shoul be fairly easy for you to find a listing for your country.

the bumblebee might be https://en.wikipedia.org/wiki/Bombus_ruderarius or it might be bombus subterraneous but this last one is rare to find in the north of europe.


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Large congregation of birds?
This year in October, I saw a lot of robins, male and female, finches and chickadees, and geese flying south.
Surprisingly I didn't see many juveniles from previous broods. My guess is that juveniles are harder to see.
And the robins were flying above me, looking for worms below me, and most ended up in tall shrubs. The finches stayed in place longer than the robins.
So why this big congregation of birds when it is still going to be relatively warm for most of the fall(which it ended up being)?
I live in ohio where it usually gets down to -4 in January and 90+ during the summer.

So, we typically think about migrating birds as living somewhere (North) and then traveling South for the winter. This way of thinking is actually not accurate according to a number of ornithologists, including many I used to work with/for. Thy suggest that the birds live in the South and migrate North to breed and to avoid overcrowding of Southern locales. (Though see this article that found support for the more often assumed N-to-S direction of migration). If 'South' is in fact their 'home,' then perhaps they will venture there regardless of weather patterns. However, perhaps neither of these thoughts applies to short-range migrators like robins.
Also, many birds migrate during the dark hours of the night, so I wonder if the birds you saw were even migrating, per se, or just moving about regionally.


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awakening effects of light
I tried reading by light from a neighbouring room and felt sleepier than if my own lights were on.
Is there a formula for the intensity of light vs physiological preparation for sleep(calcium, melatonin)? Or is there a threshold intensity below which the body goes to "sleepy mode"?

It appears that short wavelength light (that is light around the blue and purple end of the electromagnetic spectrum) does have a significant effect on melatonin levels and the 'alerting response'.

Exposure to 2 h of monochromatic light at 460 nm in the late evening induced a significantly greater melatonin suppression than occurred with 550-nm monochromatic ligh - See more at: http://press.endocrine.org/doi/abs/10.1210/jc.2004-0957#sthash.feusLJf4.dpuf

Note that 450nm wavelength light is blue and 550nm light is yellow.
Interestingly, there is some evidence that occular photoreceptors (being neither rods nor cones) play a role in setting the circadian clock. These researchers hypothesize that retinal ganglion cells (nerve cells) are photo-receactive and play a role in regulating the circadian clock via innervation of the hypothalamus in the central nervous system.

Light synchronizes mammalian circadian rhythms with environmental time by modulating retinal input to the circadian pacemaker—the suprachiasmatic nucleus (SCN) of the hypothalamus. Such photic entrainment requires neither rods nor cones, the only known retinal photoreceptors. Here, we show that retinal ganglion cells innervating the SCN are intrinsically photosensitive. Unlike other ganglion cells, they depolarized in response to light even when all synaptic input from rods and cones was blocked. - Science 8 February 2002:
  Vol. 295 no. 5557 pp. 1070-1073
  DOI: 10.1126/science.1067262   http://www.sciencemag.org/content/295/5557/1070.short

So, while there is no 'formula' per-se, we might conclude that higher energy wavelengths (that is shorter wavelengths near blue and purple) are more effective in suppressing melatonin and more effecting in keeping you awake, as opposed to lower energy wavelengths like yellow and red.

I don't believe either is the reason. Back in the day of early man, the different intensity levels of light was used as a signal to our body's "master clock" to tell us when it was time to go to sleep. So to simply put it, when exposed to less intense light, such as artificial light, its picked up as the dimmer, less intense, light akin to when historically we would be getting ready to go to sleep.

There are new studies that are challenging this hypothesis, but there is some degree of speculation when trying to work out biochemical reactions of our prehistoric ancestors and how those genes affect us today.


text:
Mesophytic Climax community in succession?
My textbook says that in all cases of ecological succession (xerarch, hydrarch, etc.), the ultimate climax community, assuming constancy of environment, is a mesic community. Xeric or hydric pioneers are ultimately succeeded by mesic climax communities. Why is this so? In an environment under consideration, if for example water stress prevails (characteristic of xeric environments) shouldn't the final community be xeric and hence better adapted to the environment? Is my book wrong, or is there something I am missing in the understanding of the development of climax communities?
Moreover, I did find it written somewhere that mesic communities do depend on the climate of the place. But then doesn't the fact it is mesic contradict a few climatic conditions wherein ecological succession might occur?
Reference:-
Ecological Succession
Climax Community

What textbook are you referring to?

@fileunderwater I have read this in several independent sources and lengthy class-notes. Here are a few places(not the best at all) where the fact (common mesic climax) is taken as a fact in several discussions.  [1]:http://books.google.co.in/books?id=3iBRNAEACAAJ&dq=life+purves&hl=en&sa=X&ei=Q2pCUqThGofmrAewuoHABA&ved=0CEYQ6AEwBA   [2]:http://books.google.co.in/books?id=FEMOAAAAQAAJ&pg=PA45&dq=climax+mesic+conditions+succession&hl=en&sa=X&ei=EmpCUqi1NojXrQfMmIGoDA&ved=0CDwQ6AEwAzgK

I assume your question only applies to secondary succession. I would clarify this in your question.

The concept of a "climax community" has not been accepted as reality for more than 40-50 years. Frederic Clements was an early botanist examining succession in the first 20 years of the 20th century. It was Clements who developed the concept of the climax: he posited that the habitat and the populations acted upon one another in a reciprocal way until finally a stable state (the climax) was reached.
However, the work of Gleason (e.g, 1926), Tansley, Watt (1957), Whittaker (e.g., 1972), Davis (1969),  etc. have changed the field's understanding of succession and its acceptance of the existence of a stable "climax". Whittaker was first to propose the use of the term "stable state," as it carried less assumptions about the community' inability to be replaced.
It's now clear from work of countless studies and authors (along with my own research), that disturbances play a significant role in plant dynamics and that previously accepted 'stable states' are perhaps only remnants of historical characteristics of the system (see below). As a result, some accepted stable-state communities no longer appear to be the norm in some areas (likely due to both present and past disturbances and fluxes in the system). See Abram's papers for a discussion on hypotheses of this phenomenon in the Eastern deciduous forest of the U.S.
Regardless, even in a system without disturbance (which none exist), the stable-state community would be fully dependent on climate, substrate, community assembly limitations and geographic/environmental/biological filters.


text:
What's this bug that is pretending to be an ant?
I found a bug with a yellow banding in the South of France. At first I thought it was an ant, and then it appeared to be a related to a cricket.
What type of bug is it?

If you look at the wings, they look partially formed and hard -- this is indicative of this being a nymph of some type of hemipteran. (The developing wings are sometimes called "wing pads").
One group that comes to mind is the family Miridae since some species have ant-mimic nymphs.
One possibility (well, one jumping off point) is Miris striatus *

 Credit: Tristan Bantock (2008) ; Source: BritishBugs
GBIF confirms this insect is in France.
*I'm not convinced this is your species given the darker limbs and more prominent and abundant yellow in your specimen. Genus seems likely though. Miridae is a very large family of true bugs, so there are lots of potential options I'm not even familiar with...

Update: I just returned to this. I'm actually more certain this is the OP's species. I think the more prominent abdominal yellow is simply a camera angle causing the two most anterior striations to "blend" to appear as a larger spot. The prominent yellowing in this image [archive link] appears much more like the OP's specimen.


text:
Do fish depend on plants for survival?
As far as I know, all land life depends on plants for survival. Plants convert sunlight to energy using photosynthesis, herbivores consume plants, and carnivores consume herbivores. All the energy is coming through the sun and being gradually processed by this food chain. If plants were removed from the system, all animals would eventually die as they would run out of energy.
Do fish and other water creatures also depend on plant life in the same way?

It might be useful to clarify what you mean by 'plant life'. Wikipedia lists four different definitions of the word 'plant': https://en.wikipedia.org/wiki/Plant#Current_definitions_of_Plantae

In a forest creek, definitely! In the ocean, not so much

 Short answer
All marine life needs energy to survive and reproduce. "Heterotrophic" organisms get their energy from eating other organisms and digesting the molecules of their tissues for driving cellular respiration/function. Ultimately, though, entire ecosystems and food webs are dependent on the non-biotic energy (e.g., sunlight) captured by "autotrophs" (aka "primary producers") and stored in the molecules of their bodies.
Plants make up only a portion of the autotrophs present in the oceans. Photosynthesis by phytoplankton accounts for the majority of Net Primary Production (total energy stored by autotrophs minus energy used by autotrophs to live) in our oceans. Chemosynthesis of bacteria and archaea in the ocean depths account for a small degree of NPP, too.
Heterotrophic organisms eat the autotrophs, and higher trophic heterotrophs eat lower trophic-level organisms. Dead matter (still containing energy-rich molecules such as sugars and fats) drift to lower ocean depths to provide organisms farther from the photosynthetic surface regions with most of their energy. At all trophic levels, energy is used to drive cellular work or lost as heat; as such, less and less energy is available at higher trophic levels and therefore necessitates eating more and more food.

 Illustration by Tim Gunther. Source: National Geographic
SUMMARY: all marine organisms are dependent on primary producers, most primary producers are photosynthetic, plants are responsible for a significant (though minority) amount of productivity in oceans, and phytoplankton account for the majority of energy capture in our oceans.
 Long answer
The Basics
All biological systems on earth require energy and matter for survival. Primary producers are the organisms that acquire energy from non-biological sources to make them available to the rest of the biotic component of the ecosystem (i.e., their associated food web; sometimes visualized as an energy pyramid).

Most commonly, primary producers (or autotrophs) acquire energy from the sun, and therefore are referred to as photoautotrophs. Other organisms, however, acquire energy from non-solar sources (e.g., thermal vents and cold seeps at the ocean bottom), and are termed chemoautotrophs.

Radiosynthesis might also be a thing...

If all other organisms in an ecosystem depend on these primary producers as an energy source, it's important to try to quantify how much energy the autotrophs are converting from non-biotic sources and storing in their cells. We can quantify this in terms of productivity:

Gross primary productivity (GPP) is a measure of the conversion rate of the above non-biotic energy sources (typically solar) into stored chemical energy (typically in sugar molecules) by the autotrophs.

Net primary productivity (NPP) is essentially GPP minus energy used by the autotroph to survive (i.e., respiration).

Read here for more information about energy flow basics.
Primary Producers in Oceans
Although photosynthetic plants are the best known primary producers, they are not the only autotrophs on earth. In fact, the large portion of ocean productivity is a result of phytoplankton, a diverse collection of photosynthetic protists and cyanobacteria.

 Image source: NASA, originally from Sally Bensusen, NASA EOS Project Science Office
The photosynthetic activity of plants and phytoplankton provide the majority of NPP for the entire ocean, but they are both limited in where they are located.
Sunlight is limited by water depth, reaching depths of less than 300 m.

 Image source: NASA
Since sunlight-availability dictates NPP to such a large extent, we can divide the ocean into vertical zones based on light availability. Only the top 200 m, referred to as the euphotic zone, has enough sunlight available for photosynthesis.

 Image source: NOAA
Both of these photosynthetic organisms are also limited by nutrient availability.

For example, phytoplankton are most abundant in upwelling zones where sinking nutrients are brought back up to the ocean's surface. These occur both in the open ocean and along coastlines.

Plants, which absorb nutrients through root systems, are further limited by the availability of substrate within the euphotic zone. In other words, they need somewhere to "anchor" down. As such, plants are only found along continental shelfs or other shallow benthic or sedimentary regions within the euphotic zone. In other words, we would say plants are limited to coastal or littoral zones.

Although the majority of production in oceans is a result of euphotic photosynthesizers, very small amounts of production are the result of chemosynthesis at thermal vents and cold seeps in deeper ocean depths. the chemoautotrophs here are all bacteria or archaea.
NPP of our Oceans
So far we discussed the importance of net primary production (NPP), the autotrophs responsible for the ocean's NPP, and the limitations of where such autotrophs can live. The question still remains: to what degree do the oceans rely on these variable sources of NPP?
According to Fox et al. (2020), "Assessments of marine primary production...are made difficult by the extreme plasticity in phytoplankton physiology". However, certain broad trends are apparent.
Well, given that both plants and phytoplankton can exist in coastal/littoral zones, these zones (especially those associated with estuaries bringing in additional resources from freshwater systems), tend to have the greatest NPP per unit area of anywhere in the world.
However, since the pelagic, or open-water, portions of the euphotic zone make up such a large percentage of the earth's surface (~70%), this so-called epipelagic zone accounts for more NPP per year than any other biome or life zone globally just due to the immense area/volume for phytoplankton to live and photosynthesize.

Although phytoplankton make up <1% of the earth’s photosynthetic biomass, Field et al. (1998) estimated such phytoplankton are responsible for almost half the world's annual NPP.

George Kling (University of Michigan) provides 2 simple graphics demonstrating these two points on a course website of his here. I've copied lower quality images here for reference:

 Modified from figures 4-5 of George Kling (University of Michigan) course page
Since only autotrophs can convert non-biologic forms of energy into chemical stored energy that heterotrophs such as fish and other water creatures can consume, all non-photosynthesizing organisms throughout the ocean's depths rely on the consumption of these autotrophs (or lower trophic-level heterotrophs) for energy. In fact, according to sigman and Hain (2012), usage of the energy captured but autotrophs and utilized by higher-trophic heterotrophs is so robust that all but <1% of the energy initially captured ever reaches the ocean floor as fallen debris/wastes/decomposing "snow".
As mentioned previously, a minor degree of chemosynthesis along the ocean floor exists, but such chemosynthesis adds minimal NPP to those zones. I could not quickly find a source that quantified the degree to which NPP of these deep zones comes from chemosynthesis (though see McNichol et al. (2018) for a fairly recent publication discussing and examining this topic). However, such chemosynthesis can only occur at thermal vents or cold seeps and therefore are quite limited in their spatial scope. Suffice it to say, that a very limited amount of NPP come from such chemosynthesis and the degree to which chemosynthesis adds to the NPP is spatially variable based on the presence/prevalence of inorganic energy sources such as thermal vents and cold seeps.

Further reading:
Chapter 17 "the Flux of Energy through ecosystems" in Begon, Townsend, and Harper. 2006. Ecology: From individuals to ecosystems. Blackwell Publishing, Malden, MA, USA.
Sigman, D. M. & Hain, M. P. (2012) The Biological Productivity of the Ocean. Nature Education Knowledge 3(10):21 [see here]

Citations:
Field, C. B., Behrenfeld, M. J., Randerson, J. T., and Falkowski, P. G. (1998). Primary production of the biosphere: integrating terrestrial and oceanic components. Science 281, 237–240. doi: 10.1126/science.281.5374.237
 Fox, J., Behrenfeld, M.J., Haëntjens, N., Chase, A., Kramer, S.J., Boss, E., Karp-Boss, L., Fisher, N.L., Penta, W.B., Westberry, T.K. and Halsey, K.H., 2020. Phytoplankton Growth and Productivity in the Western North Atlantic: Observations of Regional Variability From the NAAMES Field Campaigns. Frontiers in Marine Science.
 McNichol, J., Stryhanyuk, H., Sylva, S.P., Thomas, F., Musat, N., Seewald, J.S. and Sievert, S.M., 2018. Primary productivity below the seafloor at deep-sea hot springs. Proceedings of the National Academy of Sciences, 115(26), pp.6756-6761.
 Sigman, D. M. & Hain, M. P. (2012) The Biological Productivity of the Ocean. Nature Education Knowledge 3(10):21 [see here]

Great answer. Followup questions: I understand that unlike land plants, phytoplankton can move around. Does it do so strategically, like an animal? Does it run away from predators and such?

@Ram most phytoplankton are non-motile, and simply move along with the ocean currents. I suppose dinoflagellates can move minor distances with the use of their flagella, but they are so small that I'm not aware of any intentional mass movement of phytoplankton worth noting. See here and here for more info.

@Ram although phytoplankton don't generally move strategically, the heterotrophic  zooplankton that feed on them do: https://www.nature.com/scitable/blog/saltwater-science/what_makes_plankton_migrate/

They're heterotrophic though, so they still maintain the rule of "a creature that does photosynthesis can't move"

Yes, photosynthesis provides nearly all of the ocean's biomass and energy. The best is to study oceanic food chains and webs.

It looks like there aren't enough plants in the ocean because they don't form huge reserves of foliage and branches... 10% of land plant mass dies and is replaced every year, and 100% of oceanic plants die and are replaced every week:
"Biologists set out to estimate the total biomass of phytoplankton and calculated that less than one billion tonnes of the single-celled microorganisms were alive in the ocean at any one time. There were 45 billion tonnes of new phytoplankton each year, 45 times more than their own mass at any given time. The phytoplankton would therefore have had to reproduce themselves entirely, on average, 45 times a year, or roughly once a week. In contrast, the world's land plants have a total biomass of 500 billion tonnes, much of it wood. The same calculations showed that the world's land plants reproduce themselves entirely once every ten years.
https://www.nature.com/articles/483S17a
Every step of the marine energy pyramid has about 10% efficiency, so the shrimps and zooplankton take about 10% of the phytoplankton energy, then small fish 1%, and big fish 0.1% of the plant energy.
For every 500,000 units of radiant energy that hit the ocean surface, 2% is converted to phytoplankton at the base of the trophic pyramid, and the 500,000 units are necessary for every 10 units that a tuna consumes. https://oceantracks.org/sites/oceansofdata.org/files/energytransfer.png
https://en.wikipedia.org/wiki/Marine_food_web
In biology, we typically study coccolithophores and phytoplankton to learn the marine food web.
Areal map of sea chlorophyll in Mg/m2.

@theforestecologist I've found a quantitative estimate of the biomass of phytoplankton in the oceans, it's 1 billion tonnes of phytoplankton at any one time versus 500 billion for terrestrial plants including their wood. https://www.nature.com/articles/483S17a

@theforestecologist The researchers said that the average kg of oceanic vegetation survives 7-8 days, and the average kg of terrestrial vegetation survives about 10 years. The photosynthetic activity of all the lands and all the seas are about the same, a bit higher for terrestrial vegetation.


text:
Is there a quantitative report for cortical homunculus?
Almost all websites that I see for cortical homunculus only show the final picture with some qualitative descriptions such as "hands have more dexterity and occupy more motor cortex."
But is there a numerical table for their percentages?
Lips and tongue are big, but how big? 13%? 17%?
Is there a quantitative report for this?

I think you'd appreciate reading an 80-year update (Catani, 2017)) of the original paper (Penfield & Boldrey, 1937).
Four things come to mind (with commentary from Catani 2017 sprinkled throughout:

I would guess that certain inconsistency between individuals makes such a quantitative approach difficult.

Known overlap between body parts in any given region of the cortices makes such quantification tricky

From Catani, (2017):

Surprisingly, the picture that emerged from their work was a clear degree of functional overlap between stimulation fields rather than an orderly sequence of segregated areas as their homunculus suggests....

These maps indicate a high degree of overlay between different body parts, especially in the proximity of the central sulcus. Interestingly, the range of functional overlaps varies from expected—such as tongue and mouth, or arm and hand—to intriguing—such as mouth, arm and hand

How one determines the "regions" that each body part maps to can be done in various ways that would each create a different homunculus with parts therefore associated with slightly different region.

See Figures 2 and 4 in Catani, (2017) to see how redrawn homunculi vary in their relative proportions depending if they are proportioned based on stimulation areas, number of stimulations, or vertical length of surface maps for each body part.

The homunculus was never meant to represent quantitatively-discernable regions

From one of the original authors (Penfield) in a later publication:

such drawings may easily become confusing if too much significance is attributed to the shape and comparative size (Penfield and Rasmussen, 1950)

From Catani, (2017):

this little man, like many other figures that may naively populate our collective imagination, is just a metaphor for the complex neurological mechanisms that we strive to comprehend in their entirety

Note: I'm sure someone has tried to quantify as you've asked, so I encourage you keep looking. I would just guess that such efforts would best be found using search terms like "high field functional MRI" rather than "homunculi."

Citations:

 Marco Catani, A little man of some importance, Brain, Volume 140, Issue 11, November 2017, Pages 3055–3061, https://doi.org/10.1093/brain/awx270

 Penfield W , Boldrey E. 1937Somatic motor and sensory representation in the cerebral cortex of man as studied by electrical stimulation. Brain 60: 389–440.

 Penfield W , Rasmussen R. The cerebral cortex of man. New York, NY: The Macmillan Company; 1950.


text:
What part of food gives the blood red color?
Roughly, what I know is, when we eat food it goes into our: Stomach > Small Intestine > Large Intestine > Rectum. So, it just moves through a digestive pipe.
What I don't understand is, what part of the food is responsible for blood's color and how does the food that we eat mixes with blood?

The red colour of blood isn't actually to do with food at all.  The primary purpose of the blood is to carry oxygen to all the cells that require it to release energy.  Red Blood Cells are filled with an iron containing pigment called haemoglobin.  When it has oxygen bonded to it, haemoglobin  has a bright red colour - it is this that gives blood its red colour.
In terms of how food enters the bloodstream, it is first broken down into extremely small constituents.  This is done by mechanical action (i.e. chewing and the squeezing movement of your digestive system) and by chemical action through the use of enzymes.  Enzymes are proteins that are secreted by various glands in the mouth (and are therefore contained in saliva), stomach and both intestines.  These chemically break large food molecules down into small products such as glucose (sugar) and amino acids (protein-building blocks) amongst other things.  These then move across the wall of the intestines and into the bloodstream, which are separated by only one cell:

Unfortunately that's the best image I could find.  The intestine is everything outside of the pink layer (which is the wall of the intestine).  The small molecules are able to pass through the pink layer and straight into the blood stream.  The picture shows a fold in the wall of the gut, which increases its surface area so allows more molecules to diffuse across.

Ok, I understand the intestine part. So, the iron in the food is responsible for creating hameoglobin which is bounded with oxygen to form red blood cells? Please feel free to correct me.

@user132314 yep, that's pretty much it :)

Just one slight correction - red cells aren't coated in haemoglobin; the haemoglobin is to be found inside the cells.

In essence, some of your food contains iron (especially red meat). This is taken up by your body and integrated into the haemoglobin protein which red blood cells contain in high amounts.
The iron in haemoglobin can bind oxygen (it does this when it passes through the lungs) which enables the red blood cell to carry it through your blood circulation.
The colour of blood comes from this haemoglobin. When the iron is binding oxygen, it is red. Otherwise, blueish-red. (http://www.ebi.ac.uk/interpro/potm/2005_10/Page1.htm)

Ingested food is digested within the digestive canal. This means that it is broken down into smaller molecules that are then transported into cells lining the digestive canal (by proteins that expend energy to do this). The nutrients are then further transported until they reach blood vessels (or, in the case of lipids, lymphatic vessels, which eventually empty into veins). However, the 'pigment' that gives blood its red color is generally constructed from smaller molecules and atoms within the body, and not directly acquired from food.
Ultimately, the red hue in human blood is due to a protein known as hemoglobin. Each hemoglobin protein is bound to four 'heme' molecules, and each of these are in turn bound to a Fe2+-ion* (a form of iron) and either O2 (oxygen) or CO2 (carbon dioxide). All of these components are required to give hemoglobin (and thus blood) its distinct hue.
The molecules derived from food that are used to build the complete hemoglobin complex are:

Amino acids

Used to synthesize the actual hemoglobin protein. Obtained from dietary protein, as free amino acids, or (in the case of non-essential amino acids) synthesized from other molecules.

Succinate

Used together with glycine (an amino acid) to synthesize heme. Most succinate is derived from lipids (e.g. fatty acids), carbohydrates or amino acids in food.

Iron

Obtained from a variety of dietary sources.

CO2

Mainly produced at the final step of aerobic energy production where mitochondria break down carbohydrates, lipids or amino acids to form water, CO2 and chemical energy.

O2

Almost exclusively obtained from the air via direct absorption in the lungs.
For more information on how proteins such as hemoglobin are synthesized from amino acids, you could see e.g. this video. For more information on metabolic pathways, I suggest having a look at this map. In the latter, you can focus on human metabolic pathways by unchecking "Unicellular organisms & Fungi" and "Higher Plants" in the menu. It should be noted, though, that this only describes metabolic pathways, and does not go into much detail in terms of how these processes actually work.

*Except in the case of methemoglobin, which has bound a Fe3+-ion and cannot bind O2.


text:
Why can nervous inflammation radiate symmetrically in the limbs?
I have had carpal tunnel syndrome in my hands this week, when the nerve in the pith of your palm, through thumb and index, is pinched, and swells, inside the wrist ligament tunnel.
In a few days, the inflammation declared itself in the other wrist. It's usually the case with CTS, it's rare that a person will have problems in only one had.

As soon as one hand is injured, the other tends to seize up and stop functioning as badly as the first one, within a week or so.

Why and how does a nervous injury such as CTS radiate symmetrically through the nervous system, differently from a sprain or a contusion?
What other factors in neuroscience demonstrate nervous symmetry, related to the CTS symmetry problem?

Padua et al. (1998) did find that 87% of followed patients developed bilateral CTS (i.e., carpal tunnel syndrome in both hands).

Most patients that develop unilateral symptoms, eventually have the symptoms spread to the contralateral (opposite) arm.

Bagatur & Zorer (2011) found that 59% of patients they followed reported bilateral symptoms initially, while 73% of remaining patients had symptoms eventually develop in the contralateral arm (even after receiving surgery on the first!)

So why? From what I could gather, we don't really know. From Bagatur & Zorer (2011):

we assume that bilaterality may be time-dependent... [but] a definite conclusion could not be drawn.

However, research regarding "double crush syndrome" suggests that perhaps issues closer to the cervical spinal cord may play some role:

Pierre-Jerome & Bekkelund (2003) found that cervical intervertebral foramina were narrower in observed patients and affected nerve roots.

Although their research provided evidence for ipsilateral double crush symptoms, their study provides credence to the fact that more cervically-oriented issues (often which should show up bilaterally) could lead to CTS symptoms.

Not the greatest of answers, but a thorough search really didin;t turn up anything more recent or helpful. I'll update if I find additional info.

Citations

Bagatur, A. E., & Zorer, G. (2001). The carpal tunnel syndrome is a bilateral disorder. Bone & Joint Journal, 83(5), 655-658.
Padua, L., Padua, R., Nazzaro, M., & Tonali, P. (1998). Incidence of bilateral symptoms in carpal tunnel syndrome. The Journal of Hand Surgery: British & European Volume, 23(5), 603-606.
Pierre-Jerome, C., Bekkelund, S. I., Pierre-Jerome, C., & Bekkelund, S. I. (2003). Magnetic resonance assessment of the double-crush phenomenon in patients with carpal tunnel syndrome: a bilateral quantitative study. Scandinavian journal of plastic and reconstructive surgery and hand surgery, 37(1), 46-53.


text:
Algae or Lichen identification. Coastal BC, Canada
I have tried all books and internet resources I know of, but I still have no idea what this might be — a lichen or something else.
At first glimpse, I thought it was something man-made and unnatural, but then I looked closer and saw how it appears to be attached and growing. It grows on exposed rocks well above the high tide. The photo is taken in late March, on northern Vancouver Island. It's loosely attached to the rock.
It was somewhat abundant around the general area (within of a few km), but I haven't seen it elsewhere - although I'm not from BC so there might be a lot of this around.

The water droplet in the lower right corner give a rough sense of scale.
Edit:
Adding another photo in which I just noticed a streak of white, which I included in original resolution.

Possibly small (young) specimens of Usnea rubicunda

The growth pattern doesn't appear to match any photos or description of U. rubicunda I've seen, but it's not like I've got a better suggestion. Added a 100xp bounty to whoever gives a plausible answer. Maybe it's not even a lichen (But what else?). I regret not having taken a sample of it home, thought it'd be easy to identify given the color...

I want to propose you expand your search to a broader taxonomic scope. Specifically, I think you might be looking at a species of "red" green algae (family: Trentepohliaceae).

From Nelson et al. (2011):

All Trentepohliaceae have filamentous growth forms and often contain large amounts of carotenoid pigments (ß-carotene and hematochrome), causing the algae to appear yellow orange in color (Thompson and Wujek 1997, Lo´pez-Bautista et al. 2002).

The Trentepohliaceae contains five genera: (Trentepohlia, Printzina, Phycopeltis, Cephaleuros and Stomatochroon) and 70+ species worldwide.

For example, the following algae (picture from England) looks fairly similar to your specimen:
Trentepohlia aurea

 Source: David Fenwick
If your specimen is a species in this family of algae, it is most likely in the Trentepohlia genus (or possibly Printzina genus).
Trentepohlia is a genus of filamentous chlorophyte green algae in the family Trentepohliaceae.

Typically orange or yellow in color.
Live on tree trunks and wet rocks or symbiotically in lichens.

Here's a picture of a free-living Trentepohlia species from coastal Oregon, USA:

 Source: Richard C. Hoyer (2015)

The source notes that the specimen was simply ID'd as "Trentepohlia sp." by Tim Rodenkirk (Botanist with the Coos Bay BLM in North Bend, Oregon).

That seems like the right genus and I lift my hat in honor to you. Thank you for an excellent answer! I did doubt that it was a lichen, but I just couldn't think of what else it might have been as I was unaware of terrestrial algae with such a growth.

Excellent find! I am surprised to see filamentous algae growing in such a dry habitat. Usually they grow under water or in very wet conditions.


text:
Can anyone identify this caterpillar / cocoon?
This insect is about 0.5 mm in length, so it is very small. It doesn't have legs I don't believe, I am not too good at this but I don't know if it's a worm or more like a cocoon for something.
I do find this alarming because I found this one underneath my bed sheet on the mattress. Now I do recall seeing something similar on the crack of the shaky tile floor, so I can't tell if it's just an apartment pest or it actually lives in mattresses.
Location: Toronto, Canada

It's carpet beetle larvae.
It's a serious pest, right behind the bedbug. The larvae were found on an old mattress.
I found about 4 more afterwards.

This could probably be many different species in the family Dermestidae, which often have fairly similar looking larvae. The carpet beetle is a good bet thought since many of the other common species feed on animal materials (food, insect collections, fur, leather etc.)


text:
Please identify bird call / animal call
What species is making this sound?
You can hear it from the opening samples of this song: Earthgarden by Nada (2003).
I wish to study the frequency distribution of the bird call.

just to know the species of bird in the sample. thanks

Sounds like a Curlew (Numenius arquata).

http://www.british-birdsongs.uk/curlew/
https://www.youtube.com/watch?v=q7V25M0szqU

Awesome knowledge there. it may not be the precise same bird but it is very close and it may be, unless someone has a better idea, we can say it's as good as same bird.


text:
Do people often blow out the air from their lungs a lot when living in the cold condition to keep their lungs warm?
Do people often blow out the air from their lungs when living in cold climatic conditions to keep their lungs warm?
I ask this question because it could connect to how people in different areas construct linguistic sounds.
For example, the Germanic families of Language (German, English,...) use a lot of air from the lungs to construct the sound?
Is that because the Europeans living in cold climate often blow out a lot of air from the lung to keep warm and as a result gradually they construct air-driven linguistic sounds?
For people living in warm climates (ex: Sino-Tibetan language like Chinese, Thai), we mostly use the tongue to construct sounds, and we use very little air from our lungs to make sound.
I posted this question to some forums & some people said it’s baloney. However, there's one thing for sure, the environment shapes how local people construct sound. People construct the sound like that because it is constrained by something. One thing can not stand alone, it must be the karma or outcome of something else.

There's warm parts of Europe and cold parts of China... a more proper way to test it would be to test the same language in hot and cold areas and/or at different seasons

Heat loss hypothesis:
I would rather think that blowing while speaking means that one has to inspire often and therefore he would lose much heat by convection. According this hypothesis, I would rather expect to see southern people blowing lots while speaking.
Metabolism hypothesis:
We might say that at low temperature the metabolism increases and therefore the consumption of oxygen should increase. As shown here for example. This would make blowing much air more profitable for people living in cold environments.
Articulation hypothesis:
One might as well hypothesize that the cold would tend to make articulation more complex and using much air would help to be well understood.
Note: It would be interesting to look at many local scales if it is indeed true that the colder the more air people use. At global scale, I am afraid that the observations are quite dependent and statistically speaking, there is not much evidence that cold environment correlates with blowing much air while speaking

But in warm, particularly in tropic climates, you don't loose as much heat by breathing as with cold (and therefore also dry) air: the incoming air is warm and moist already. And I suspect that loud and clear pronounciation of Germanic does not need more breath, but rather better resonance and other techniques that probably do not lead to more breathing (otherwise, how could one survive a long monologue on a theatre stage without hyperventilation)

@cbeleites Well, in my answer I assumed (as did the OP) that germanic languages need more breath. But I have no idea if this is true. In your answer you criticize this assumption and I agree with you.

I guess the main point is that 'blowing out air' doesn't help to 'keep the[ir] lungs warm' anyways as you explain in your 1st paragraph. I just added "experimental" hints that the things one does do to save heat in cold air anyways do not include speaking...

In a cold climate, do people often blow out the air from their lungs a lot when living in the cold condition to keep their lungs warm?

No, and it wouldn't make any sense: breathing more means inhaling more cold air that needs to be warmed up, so the result is a heat loss. The more so, as cold air (< 0°C) has a low water vapor pressure, while the lung likes to have the air at body temperature and well moistened. Which means that you also loose the vaporization heat of the water.
The function of moistening and heating the cold and dry air as well as recollecting some of the heat and water when breathing out is done by the nose. So the sensible (and done) thing in cold weather is to avoid breathing by mouth and instead keep your mouth shut and breathe by nose.
Nevertheless, neither German nor English, nor any of the Scandinavian Germanic languages is spoken through the nose.
My experience is that cold air (personal minimum: -40 °C) in the mouth is very unpleasant, and makes me cough as it is still cold when it arrives in the throat, but of course breathing out by mouth is less of a problem. But breathing out by mouth and in by nose means that the nose cannot recollect the heat and moisture from the outgoing air.
In any case, the amount of breathing is linked rather to oxygen demand and $CO_2$ to be gotten rid of), and even the fastest speaking people I know do not get close to hyperventilation by speaking, not even speaking German or English.
Which means that speaking Germanic languages needs less breath to produce the sounds than what you need to breathe for physilogical reasons even at not much above base rate metabolism (sitting while talking) anyways. Which would imply that the breathing difference between Germanic and Sino-Tibetan languages would not cause an important driving force in language evolution.
A side point is that I don't agree with your concept of cold climate. Both Germany and England are counted as temperate climate. Actually, Frankfurt has higher minimum temperature all year round than Lhasa (as you mentioned Tibetan in your language family).
Also note that the Indo-Germanic language family covers a range of climates from tropic to polar just as the Sino-Tibetan covers some cold regions as well), so maybe language families that are spoken only in polar regions vs. such that are spoken only in tropic regions would be better to look at (see e.g. the Wikipedia language family map).
However, there are probably some confounding influences that need to be taken into account. In cold weather, you do not sit or stand around chatting with people as much. And in the polar climates, historically farming has hardly been possible. So you have populations where hunting has been very important for survival, and regions with very low population density. Both mean that on average, you'll be silent instead of talking. As for having a chat with someone, you'd ask them in - or the length of the chat is limited by temperature.
Which means that if cold is a driving force for the type of pronouciation that evolves, it would be a rather weak link. And in any case, speaking less will overcompensate all these breathing differences.


text:
What is this bee/wasp nest?
Perhaps this is a tropical wasp. Can you identify it? Is it artificial?

What is your location? Also, what makes you think that this is a wasp nest?

Sorry, I dont know where it's from: I was researching animal nests, and I found the pic on a random trivia page. Then I searched google images, there are only 3-4 HD copies of the photo and I couldn't find the origin of it.

FYI this appears to have originated from reddit user Crabcaked from this reddit post. I added more pictures to your question here from that post

I do not believe that this is a wasp nest. What makes you think that this nest belongs specifically to a wasp species?

awesome, well spotted. I thought that reddit was joke website. I wrote that it was a wasp because the web page was called "strange places to find a wasp nest" and had household objects surrounded by nests and things.

This is likely a honeycomb created by some species of honey bee.
A beekeeper (Jessie Brown) from New Mexico shared to her blog the following photos of a "free form" bee hive some of her bees created:

 Photo credit: Nina Dubois
In that instance (as well as the one mentioned here and pictured below), the beekeeper moved some "burr comb" to a new location and the bees used that moved remnant piece to build a mound-like comb.

 Photo credit: Phillip Cairns

That is pretty amazing. Great answer!


text:
Black squirrel in France?
I saw a nearly jet black squirrel in ardeche today,  carolinensis have invaded the UK and Italy, however I didn't find news about their arrival in France. Was that black squirrel really a Canadian species?

Note that "Black morphs may also occur with Eurasian red squirrels" (Wikipedia). I have personally seen some such exemplars. while they are black they are the (smaller) size of European red squirrels. If you've seen both American and European red squirrels (in real life), it's hard to mistake them due to size differences.

Yes you are completely right. I have seen some other black morph squirrels which are Eurasian reds and some which are the same color as tree bark from a fairly dark pine tree.

Yes, Sciurus carolinensis has been invasive in France, Italy and Switzerland for quite a few years already (Bertonlino and Genovesi, 2003).
Note that the "original" distribution of S. carolinensis is over eatern Canada and USA. Not Canada only.


text:
Insect Identification - Black Cicada

I came across a black cicada in northwest Missouri last week (May 2015). I am only familiar with brown cicadas. What makes this black one different? Is it a different species, or do the brown cicadas change color at some point in adulthood?

A little digging on wikipedia seems to have answered my question. This picture of a 17 year cicada, Magicicada septendecim is pretty close to what I saw.

Furthermore, this seems to match the time and place, as the Kansas Brood of 17 year cicadas is scheduled to emerge this year and should appear in the Missouri-Kansas area. It also explains why I'm not familiar with these cicadas, 17 years ago I wasn't paying attention to them.

It is a 17-year periodical cicada, but you got the species wrong. See my answer for evidence for another of the three 17-year species!

 Short answer
This is Magicicada septendecula, one of the three species of 17-year cicada (colloquially, "17 year locust") native to the Eastern United states.

 Credit: C. Simon, Fontaine et al (2007)1
 Long answer
Periodical cicadas are the only group of dark-bodied cicadas with bright red eyes and orange/red-tinted wings (at least I don't know of any others). These cicadas, all of which are in the genus Magicicada, can be divided into 13-year and 17-year cicadas, each with multiple potential species:

17-year species: M. septendecim, M. cassinii, M. septendecula

13-year species: M. tredecim, M. neotredecim, M. tredecassini, M. tredecula

These species tend to form mixed-species cohorts called broods in which all members of a brood synchronously emerge at the same time (every 13 or 17 years). There are 23 broods found in the US that emerge in different years, and the broods are identified by Roman numerals (I-XXIII). [Source: Scientific American]

You can read more about periodical cicada broods on Wikipedia, and you can see range maps of both 13- and 17-year species here (from here) and all together in one map here: Liebhold et al (2013)2.

Importantly, only 3 broods are found anywhere in Missouri: one 17-year brood (Brood IV, the Kansan Brood) and two 13-year broods (Brood XIX, the Great southern Brood, and Brood XXIII, the Mississippi Valley Brood).

 Modified from: Liebhold et al (2013)

Brood XIX is by far the biggest brood in terms of coverage in Missouri, but these 13-year cicadas last emerged in 2011 (not 2015).

The other two broods both emerged in 2015, when the OP photographed the specimen in question, but only Brood IV is found in Northwest Missouri. So we can safely narrow the potential species down to just one of the three 17-year cicadas.

However, Brood IV does contain all 3 species of 17-year cicadas, so we'll have to keep digging...

CicadaMania.com provides the following tips for IDing these fairly similar looking species:

M. cassinii: Smaller (2.4-2.7 cm long) with black ventral abdomen

M. septendecula: smaller (similar to M. cassinii) with orange/yellow stripes on ventral abdomen

M. septendecim: larger (2.7-3.0 cm long3) with orange/yellow stripes on ventral abdomen.

We don't have the greatest view of the abdomen and we have no definitive reference for size (at least to differentiate a couple of mm), so this makes ID a bit more difficult.
However, it does appear that there are bands of orange striping seen on the lateral sides of the abdomen in the OP's image, suggesting we can rule out M. cassinii.

Lucky for us, there is one additional way to identify between the other two species. Again from CicadaMania.com:

The pronotal extension is an extension of the pronotum that lies between the Magicicada’s eye and its wing (outlined in green in the photo below). M. septendecim have orange coloring in that area, which gives us a key way to visually distinguish them from M. septendecula.

 Orange pronatal extension of M. septendecim ; Source: Cicada Mania
Sure enough, the OP's specimen does not have an orange pronatal extension...

...suggesting that the OP's species is M. septendecula!
Also, FYI: cicada adults do not change colors. The 5th molt prior to the adult stage,  which leaves behind the familiar exuviae clinging to a tree trunk, is the final anatomical change cicadas undergo in their life cycle. [See here for more]

Citations:
 1. Fontaine, K.M., Cooley, J.R. and Simon, C., 2007. Evidence for paternal leakage in hybrid periodical cicadas (Hemiptera: Magicicada spp.). PloS one, 2(9), p.e892.
 2. Lloyd, M. and Dybas, H.S., 1966. The periodical cicada problem. I. Population ecology. Evolution, 20(2), pp.133-149.
 3. Evans, A.V., 2007. National Wildlife Federation field guide to insects and spiders & related species of North America. Sterling Publishing Company.

See my related post with map and more info about broods: https://biology.stackexchange.com/a/100720/16866

It's difficult to be sure without seeing the specimen more from the side (or ventrally), but the lack of visible orange color between the eye and the wing articulation suggests that it could be one of two other 17-year cicada species, Magicicada cassinii or M. septedecula (all three species emerge synchronously; their different songs isolate them reproductively).  M. septendecim has the lateral orange color.  M. cassinii is the most common of the three species in the 17-year brood that came out in 2015.
Cicadas do not change much in appearance during their short adult lives.

Welcome and thanks for your answer.By convention we ask for sources, a verifying image of your ID and additional background info such as the distribution and habitat of your species ID. As of now, it's more of a question comment.


text:
Horned Mohawk looking insect. What is it?
Any ideas? I didn't know any other way to explain it.
I live in Indiana, USA if that helps.
Someone said it might be a "stink bug" but I'm not sure and not willing to find out!

Its definitely a True bug (Hemiptera), and based on its distinct pronotum and small head I'm guessing its a Wheel bug (Arilus cristatus). It is a common species that is also found in Indiana.
They are aggresive predators and are part of the family Reduviidae also known as Assassin bugs. Assassin bugs have a painful bite, and they inject a toxin when they stab their victim (so humans should watch out). This is not a part of the world I know well though, and there might be similar closely related species that I've missed.
Links:

Bug guide
Records in GBIF
Univerity of Florida: Entomology & Nematology

Some pictures:

I would have called it an assassin bug, but I guess you're more specific than that.

@user137 You are correct in the sense that it belongs to the family of Assassin bugs.

@ansarob Yes, they can have a nasty bite, and they inject a toxin when they stab a victim.

Right, this is definitely a wheel bug. Watch out for their bite!

This does indeed look like a wheel bug (Arilus cristatus) as @fileunderwater indicates in his now 4-year-old post.
I just wanted to add 2 bits of information:

Range: Most eastern US states, from New York to Florida, through parts of the midwest and central plains down through Texas, New Mexico and Arizona.

 Source: Bugguide.net

The University of Florida Entomology and Nematology further claims:

It has been reported from Rhode Island west to California, and south to Texas and Florida. Blatchley (1926) included Mexico and Guatemala in its range. Wygodzinsky (1949) recognized four species of Arilus in this New World genus, but only cristatus occurs in the United States

This source provides an additional map (informally created from collected resources) that shows inclusion of California, Vermont, and Mexico in the wheekl bug's range..

-

Wheel bugs are sexually dimorphic, so do not be surprised if you see a noticeable gradation in size between specimens:

 Source: Wikipedia

I don't believe there is documented geographical size differences, so ranges in size would be due to age or sex.

 Cited sources from quote (for convenience):

 Blatchley WS. 1926. Heteroptera or true bugs of eastern North America, with especial reference to the faunas of Indiana and Florida. Nature Publishing Company, Indianapolis, IN. 1116 pp.
 Wygodzinsky P. 1949. Elenco sistematico de los Reduviiformes Americanos. Univ. Nac. Tucuman, Inst. Med. Reg. (Pub. No. 473), Monograph No. 1: 1-102.


text:
How to analyse an ECG?
I have a project about extracting features from a homemade ECG. I need the PQRST points from the signal of the heart beat. The ECG I'm using has 3 electrodes that attach to the chest.
The problem is I don't know where I should define the PQRST points because the result does not look much like an ECG. I want to try to create a program later that can find those points.
Here are the raw ECG traces data taken from 3 subjects that were alcohol-intoxicated (0.2 to 0.3 promille):

I'm guessing the red and orange points here. And I'm pretty sure the green points are accurate located:

Green points is easy to locate but the orange is a little harder and the red ones are really hard to pin point out. Those points can be used to define the length of different complexes, intervals and segments of PQRST.
Which points is safe to extract? Where exactly are those points located in the graph?
Is the data too inaccurate for finding abnormalities?
Is there any other useful feature, beside heart rate, I can extract from my graph?

First bump is called P point, middle is QRS wave (as in Q-down, R-up, S-down), and last bump is T. Every feature is representation of electrical activity in certain region of heart. E.g. P bump is contraction of atrium. See more here. Bumps are P/QRS/T.
The reason why you see so many different recordings is that it was taken with many-lead ECG. Heart has very distinct shape, its atrium is on top of ventricle, it is a bit tilted to the right, etc. Your recording is a projection of electrical activity vector onto vector that connects two leads used for given recording. Pick two other electrodes and you will have different picture just because axis of projection changed.

via NIH
It seems to me that recording you show are from different pairs of electrodes, but it shouldn't matter. As you can see, different pairs of electrodes will "pick up" some processes better that the other.
Now, because ECG is electrical activity recording, heart rate is least useful information to extract from it. Measuring pulse will be less of a hassle and as accurate. But what you can do is estimate biophysicals properties of given heart. For example, distance between P and QRS (PR interval) complexes is time that it takes for heart to contract ventricle after atrial contraction. Any abnormalities will cause lengthening of PR or other change. Lengthening of PR interval often indicates 1st degree AV block (AV node is not conducting as usual).
There is bunch of information out there on ECG and abnormalities, you can find useful this page from U Utah with examples of many severe conduction abnormalities.

Can you please point out any algorithm/pseudocode which can find P / QRS / T in channels, please. I think there exist many of them but I would like to understand some basics how to do it.

@Masi what do you mean

Your answer is too generic. I would like to get some examples how you really analyse ECG with basic examples of false negatives etc QRS complexes with suspected PVCs in the immediate surrounding.

@masi well, then I would refer you to medical literature. Or some online knowledge bases, like http://www.ecglibrary.com/ecghome.php

The only abnormality which can be seen on the ECG curve is a prolonged PR Interval but only when acute alcohol poisoning has been done.
In the referenced paper the patient had consumed 3.7 g/l (3.7 per mille) which resulted in a PR prolongation of 200-300 ms. The normal PR interval is different for everybody but it normally is 0.12 to 0.20 seconds. A long PR interval will result in a first degree heart block. In your case (0.2 per mille) I doubt that you are going to see any abnormalities. But if the ECG sensor has a good sampling rate then maybe there is a chance.
The PR interval reference 1 is defined as shown here:

PR interval reference 2:

Further reading:

Normal ECG
Third-degree atrioventricular block in an
adolescent following acute alcohol intoxication. van Cleef AN1,
Schuurman MJ, Busari JO.

I think you should avoid the word only here. I would really like to see any pseudocode/software how you can detect those properies and waves in each basic ECG signals.

Beautiful work!
Whether the PR is prolonged depends on timescale om x axis (which i cannot find...).
I didn't really get the scope of this task. If you are attempting to create a computer automated interpretation of the crucial ECG intervals, waveforms and points, you are in for a very tough task (if you want it to be clinically safe). This is the subject of intense research with thousands of patents applying to it. There are also open-source software (i think MIT and Matlab has some resources on it.
Some good resources:
http://circep.ahajournals.org/content/6/1/2.full
http://circ.ahajournals.org/content/115/10/1306.abstract?ijkey=f624706cb1aa52e719908ba6fb39726f4434bcd9&keytype2=tf_ipsecsha
Www.lifeinthefastlane.com
www.ecgwaves.com (my site)
Www.bem.fi (good om electricity aspects).

This does not answer the question - answers are expected to stand alone and have links and references for further reading. Additionally one could see the promotion of your own website as critical.

you're right. i've modified the answer and included a reference to Kligfield et al which is a good starting point.

Please, no link-only answers without explaining specifically what you include. Your answer is pretty hard to read.

Additional resources for EKG tracings with analysis:
Practical Clinical Skills
EKG Academy  (my site)
Bill

This is not commercial as far as I see.

@Chris Isn't it considered spam.

@Mesentery I would simply avoid that - the cases where people post own websites are often spam...


text:
Niche overlap Index
I wanted to use the compana() function from the adehabitat package in R. I don't really understand the meaning of the data in the example they provide (from aebisher et al., 1993).
The two main arguments of the compana function are:

compana(used, avail, other.arguments…)

used
  a matrix or a data frame describing the percentage of use of habitats (in columns) by animals (in rows).
avail
  a matrix or a data frame describing the percentage of availability of habitats (in columns) by animals (in rows).

What does...

"[..] a data frame describing the percentage of availability of habitats by animals"

mean ?
By 'Availability of a habitat', I guess it means the proportions of these habitats that were not used. Isn't it? But then, how can this be categorized into different species?
I guess I am missing something easy in the functioning of this statistical tool!

One can run that in R to get more info:
install.packages("adehabitat")
require(adehabitat)
?compana
# The following code comes from the example provided in the help page
data(pheasant)
pheasant$mcp
pheasant$studyarea
compana(pheasant$mcp, pheasant$studyarea,
                   test = "parametric")

Not 100% sure, but this would be my guess:
"used" would be the percent of time spent in a certain habitat, while "avail" is the amount of that habitat that specific animal encounters in its life.  This example explains what I mean:
Say you have some sort of ground squirrel that lives in rocky outcrop(R).  Next to the hole is a field (F), and across the field are some trees(T) with squirrel food in them.  The squirrel spends all of its time in these three habitats, but it doesn't like the field much because its exposed and can be attacked by predators, so when it goes out for food it runs quickly across the field, gets food, and runs back.  Say it spends 60% of its time at home, 10% of its time running through the field, and 30% of its time in the trees eating.  Those give you your "used" numbers.  But, the relative proportion of the habitats that the squirrel ever occupies (relative size), are very different.  By area, the field is 75%, the trees are 15%, and the rocks are 10%.  In this example, your "used" matrix would look like this:
used
            R    F    T
Squirrel  0.6  0.1  0.3

and your "avail" matrix would look like this:
avail
            R    F    T
Squirrel  0.1  0.75  0.15

With this information you can do a statistics to test whether the squirrel randomly picks habitats, or prefers certain ones.  If it randomly picked habitats, you'd expect it's "used" percentages to look like its "avail" percentages, i.e. it spends ~75% of its time in the field because it just wanders around aimlessly between rocks, field and trees.  But since you observe a pretty sizable increase in time spent in low-availability habitats, you are likely to see a statistically significant preference for certain habitats (rocks for sure, and maybe trees).
Then, if you have multiple species, this program probably tests to see how similar two species' patterns of habitat preference and avoidance are, and uses that to define niche overlap.  The "avail" could be the same if they both travel through the same rocks, field and trees, but if another species has a larger foraging area, its F and T percentages in the "avail" matrix will go up relative to the R.
Again, not totally certain about this interpretation, but it seems to make sense to me from the R documentation.


text:
Which organs do cats not eat on their prey?
My female cat is a very active hunter and brings me her prey daily. Except for shrews and birds, she always eats them entirely.
This afternoon she brought me this:

It was quite large (maybe between half and two thirds of the length of a mole), and I couldn't identify it (I'm in Europe if that matters).
The prey was already dead when my cat brought it to me, and she quickly started eating it. I noticed that she didn't eat this part:

I'm not a biologist, but I guess this is the stomach of an herbivorous animal?  What's inside looked like wasabi.
Why didn't she eat it? She is not so picky with smaller animals. Is it because of the size of this one?
Are there some organs or parts of the prey that cats usually don't eat ?

When I first looks at that I thought it was a fetus of some kind!!!

That looks like some sort of rodent.  The rodent stomach, while not as acidic as the human one, is still strongly acidic:

The mouse stomach pH was 3.0 (fed) and 4.0 (fasted), and the corresponding values in the rat were 3.2 (fed) and 3.9 (fasted).

From this article
Since it's clear from the picture that the organism had just eaten (the stomach had not yet emptied), the pH would be on the lower end of that spectrum.
In humans, acidic foods often taste sour, so it may be that the cat ran into a terrible taste at the base of the esophagus that caused her to stop there, but I don't know whether the taste buds on the cat are comparable to those in a human.

I think it depends on hunger, preferences....
Domestic cats can pretty much eat it all.  They might discard items they can't digest like fur, relatively large bones... other than that what they leave behind is rather individual.
I'm guessing this cat doesn't like salads.
Typically I haven't seen hunting cats discard digestive organs.  Aside from fur and big bones sometimes they might discard a head (probably because they don't feel like dealing with the skull).

We had a hunting cat years back that seemed to leave the kidneys alone when eating rabbits.

It is known that Grizzly bears catching salmon during times of plenty only eat the head (the fish brain, as any brain, is rich in fats, easy to digest and basically luxury food). However, in times of shortage they consume pretty much the whole fish, as every scrap of food, even untasty and non-nutricious tail fins and the likes are better than nothing.
Your cat will chase, hunt and catch prey following its hunting instincts. When its well-fed, however, your cat is not really hungry and will eat only the tastiest and easiest parts (say liver etc), but will definitely skip smelly intestines with undigested plant material.
I can try to find a reference to the Grizzly study (pretty interesting study :-)

My cat brings us those too. So I guess it is very common to cats to not eat that part of a animal. My cat brings us one almost every morning so it is very common. This item they leave behind is called a gizzard. A gizzard is a part of the stomach that has strong acid in it so they know not to eat it.


text:
Identifying a shrub with unusual "many shoots" growth behavior
While recently hiking in the southern mountains of New Hampshire, we came across a plant, and some of them were exhibiting what we interpreted to be a disease, or least unusual growth. On some of the nodes, there were a large number of extra stalks:

On each plant, the number and locations of these things varied, and not all of them had it. And we first assumed it was some ivy, or parasite, or separate plant, but it seemed pretty clear to us that it was coming right from the same branch.
We soon saw there were dead versions of this plant, and all of them had this "extra shoot" variation:

So we reasoned that no matter what this thing was -- natural variation or some kind of disease -- it was killing the plants.
Google image search was no help. It possibly identified the plant as a "viburnum", but was unable to help with the growth.
Anyone know what plant this is, or what this growth behavior is the result of?

Given the location and the harsh weather there, one possibility is that this is a kind of scrubby growth pattern in which the harsh weather kills a portion of the plant and then fresh shoots emerge the next spring.  If you found these in more exposed locations that would be consistent with this idea.

They not in exposed locations - quite the contrary, generally around the trail, underneath a canopy. But something to look up at least!

Based on the poorly-detailed pictures, I'd say it doesn't look like a Viburnum species to me sinply because Viburnums are oppositely arranged. If leaves are somewhat toothed (again, I can't tell), I'd say the leaves remind me of a cherry...

Possibly an example of a "Witch's Broom."

Witch's Broom is a deformity in plants (typically woody species) which typically causes dense patches of stems/shoots to grow from a single point on the plant. The name comes from the broom-like appearance of the stems.1
Witch's broom may be caused by many different types of organisms, including fungi, oomycetes, insects, mistletoe, dwarf mistletoes, mites, nematodes, phytoplasmas, or viruses.2

Sources:
1. Wikipedia
2. Book of the British Countryside. Pub. London : Drive Publications, (1973). p. 519
 Image1. Gardeningknowhow.com
Image2. Iowa state University

Oh awesome, this has got to be it. The Arnold Arboretum (in Boston), has a page which lists common species in my area to be afflicted by this - although it does not seem to include something like what we saw. I'm going to investigate a few more days, but this seems like the likely answer