5. The early post-war period (1946-1965)
The early post-World War II or pre-Marcos period (1946-1965) saw basically the continuation and intensification of the semi-feudal socioeconomic system in the whole country, under the neocolonial setup and the acceleration of “growth trends” (actually the seeds of crises) that emerged before the war. In this section, we focus more specifically on the impacts of urbanization as seen in Metro Manila, and the impacts of the nationwide expansion of roads and motor vehicles.
Urbanization in the Philippines is broadly reflected by the increase in towns and cities with 100,000 residents or more—from nine in 1900, to 21 by 1970. More clearly, this is seen in the big jump of residential populations in the chartered cities, from 3.9 million (14% of total population) in 1960, to 7.4 million (20% of total) in 1970. Take note that this urbanization did not reflect real industrialization, but the growth of non-industrial activities (mostly services) outside of agriculture and served the semi-feudal economy and semi-colonial system.
World War II destroyed much of Manila and displaced many urban communities. The postwar reconstruction period was generally unplanned and chaotic despite government planning efforts. In-migration from other provinces accelerated the growth of Manila, newly created Quezon City, and the towns of surrounding Rizal province (with its two cities Pasay and Caloocan and fast growing Makati), such that by the 1960s, planners had started viewing the bigger territory as “Greater Manila area” comprising 4 cities and 17 municipalities.
The war also destroyed a lot of infrastructure, including bridges, railroads and Manila’s tranvia (electric tram) system, not to mention killing off the huge prewar horse population. Japanese war reparations poured in, supposedly to help rehabilitate infrastructure, but much of it was pocketed by corrupt bureaucrats and public-works contractors. While PNR operations struggled to survive, the tranvia system was finally abandoned. These created huge deficits in urban and inter-provincial transport, which were soon filled up by jeepneys (from reconditioned military surplus motor vehicles) and buses (initially made from converted military trucks).
Nevertheless, road-building dramatically expanded together with increases in motor vehicles. Bus transport (PUB) companies began to dominate provincial routes, competing with PNR in Luzon. The rise to dominance of the urban jeepney (at first small AC or auto-calesa, later bigger-capacity PUJs) and its gradual expansion to nearby provinces also date from this period. Private car ownership also expanded, but the price of imported (mostly US-made) cars limited ownership only to the wealthy and upper-middle classes and government and private offices.
The history of the local automotive industry deserves its own research and separate paper, especially those jeepney assemblers (e.g. Sarao, Francisco Motors and others) that struggled to survive on a thriving local market until they were eroded by US and other foreign firms. While the import-substitution local strategy of the 1950s clearly encouraged the patchwork development of certain manufacturing processes that helped nudge local jeepney assembly forward, this proved short-lived and should provide valuable lessons for future attempts to kickstart local automotive manufacturing.
Another significant development during this period was the rapid depletion of forest resources and shrinkage of frontier lands. The remaining frontier areas in Northern Luzon, Mindanao and Palawan-Mindoro were gradually filled up with new towns, which were eventually interconnected through new roads (many of them old logging roads) and smaller ports and wharves. Marcos would later take advantage of this by launching an ambitious infrastructure program, in which he and his cronies would benefit.#
Author’s note: These are Sections 1-7 of “History of Philippine land transport”, which in turn is Part II of a draft framework paper on Philippine mass transport that I’ve been writing with the help of representatives of KMU, PISTON and a few others.
We saw the value of tracing the roots of our current-day transport problems through the broader socio-historical context, in order to better appreciate the challenge of seeking long-term solutions. Historical accounts are also inherently fascinating, like unearthing one’s ancestral lineage.
As specialized histories typically require specialized research, this historical backgrounder will obviously stand as a work in progress. It is not comprehensive, but rather imparts focus on land transport trends related to urbanization. What was supposed to be Section 8, on the last 30 years (1986-present), will be included in Part III which will dwell with the current-day land transport conditions and problems. # nordis.net
Continued next week


We’ve often heard someone’s memory described as 'weak' or 'strong'. But with the majority of psychological memory models drawing on information processing analogies with terms like 'storage', 'retrieval', and 'input', where did the idea of memory’s strength come from?
In a recent article published in the Journal of the History of the Behavioral Sciences, Alan Collins of Lancaster University reviewed British and American texts dating between 1860 and 1910 that focused on improving human memory. By extending his analysis to include those texts aimed at popular audiences as well as those intended more specifically for academics, Collins noticed a trend during this period in which the importance of enhancing natural memory was emphasised over the creation of artificial memory systems.
The idea of 'artificial' memory was used to describe systems created with the intention of supporting or improving one’s memory capabilities – be they mnemonics or some other form of memory aid. The criticism of such systems at the time was that they require too much mental effort and have only limited value in the practical sense. 'Natural' memory, conversely, was used generally to describe our innate memory systems.
Collins explains that the increasing tendency towards discussions of natural memory in the latter decades of the 19th century paralleled a wider emphasis on understanding everything as being a part of nature and therefore subject to natural laws. Guidebooks of the period connected all aspects of one’s life to their general health: a healthy diet, good (moral) habits, pure air, and both a strong mind and a strong body were key to a good character. Natural memory became wrapped up in these recommendations, often described as similar to our bodily functions, especially our muscles. The argument put forth contended that just as our muscles require exercise, training, and discipline, so too does our memory.
But just how does one 'exercise'; their memory? In short: repeated practice. The memory improvement texts examined by Collins advised readers to block out a period of time each day to actively exercise their memories. This time could be spent learning lists, reciting poetry, or recounting the events of the previous day. Focused attention on the chosen task was considered to be an especially critical component.
As Collins highlights in his conclusion, today we no longer draw on the muscle metaphor explicitly in discussions of memory, but the concept of 'strength' has remained. However, if we think about the advent of computer games and apps intended to strengthen (or, dare I say 'exercise'?) the mind, perhaps the idea of working out one’s memory is not quite as foreign as it may seem. Besides, learning a verse of poetry sounds a great deal more appealing than hitting the treadmill.
Collins AF (2014). Advice for improving memory: exercising, strengthening, and cultivating natural memory, 1860-1910. Journal of the history of the behavioral sciences, 50 (1), 37-57 PMID: 24272820
Post written for the BPS Research Digest by guest host Jennifer Bazar, who is a Postdoctoral Fellow at the University of Toronto/Waypoint Centre for Mental Health Care and an Occasional Contributor to the Advances in the History of Psychology blog.


Even though a Helmholtz coil is used most often to cancel out the Earth's magnetic field, the Earth's and Helmholtz coil's magnetic field components may not cancel out uniformly over all space. This is of significance if you wish to know how a finite magnetic object might react and align itself with such a field. This Demonstration enables you to clearly see the non-uniformity and off-axis magnetic field components, thus allowing you to determine how such an object might react. The symmetry axis of the Helmholtz coil is aligned with the Earth's horizontal magnetic field. The coils are in the
plane with one centered at
and the other separated by the radius
of the coils centered at
. The number of turns for the coils
is initially set to 25 and the vacuum permeability
is included in the equations as well. You can vary the radius of the coils, the current supplied to them, the number of turns in the coils, and the Earth's field. All units are in the MKS system.


Green prefabricated homes make a very positive environmental difference, in many different ways. When you choose green prefabricated homes you have an almost unlimited range of design options and freedom, and these homes are excellent choices if you care about the environment. These buildings are superior to homes built using traditional building methods and materials, because they do not cause the environmental damage or high energy use that lumber built homes can. Steel is a recycled material, and is an environmentally friendly building choice. Green prefabricated homes also benefit the environment because you will use much less energy to heat and cool the home. This will save you money, while allowing you to protect the environment at the same time.
Steel Versus Lumber
Most green prefabricated homes are built using steel structure and insulated panels, which are manufactured off site and then shipped in for the final construction. Using lumber as a building material causes great harm to the environment, while steel as a building material does not have the negative impact that lumber does. If you choose lumber for your new home you will cause between three and four acres of trees to be decimated, just for your house. Choosing steel in the form of green prefabricated homes means you save this same amount of trees, and help recycle three to four junk cars instead. Using steel will not only save natural resources, but help recycle scrap at the same time.
Green Prefabricated Homes Have Lower Energy Use
Steel is an excellent building material, and you will see a much lower energy use when you choose green prefabricated homes instead of traditional lumber built choices. Because prefabricated homes use the most modern technology in the construction industry they are very energy efficient. Traditional lumber construction leaves “studs” every 16 inches in your walls, which creates thermal gaps in your home. Insulated steel paneled green prefabricated homes provide full wall performance, with no thermal gaps. In addition these building choices are not at the mercy of extreme temperatures or weather conditions like traditional homes are. You can lower your home energy use significantly.
Less Waste, Less Time
Green prefabricated homes built in steel do not produce nearly much waste as lumber built homes do. The typical traditional home will be responsible for at least twenty percent waste where building materials are concerned. With green fabricated homes from steel the waste percentage drops to around one tenth of this amount, or roughly two percent waste. This lowered amount has a very positive impact on the environment, and helps protect a large amount of natural resources while minimizing waste. You can have a home that is extremely environmentally friendly when you choose green prefabricated homes.


Does technology always help reduce recruitment bias? Find out about the benefits and potential pitfalls from career and productivity writer Erika Rykun.
All people are exposed to bias and recruiters are no exception here. Most biases are unconscious; they can affect our perception, decision-making, and judgment, contributing to the possibility of misinterpretation and mistakes. For sure, people cannot be completely blamed for such weaknesses in judgement, but HR and recruitment specialists may be held accountable if they are not properly addressed within the organisation when it comes to hiring.
Real-life examples prove that even modern software may not be immune to bias. Recently, Amazon.com Inc's AMZN.O specialists uncovered a big problem in the operation of their AI-powered recruitment tool. According to a report from Reuters, the algorithm itself caused the problem, as AI algorithms learn to make decisions on the basis of historical data, which may itself contain bias samples. Could this case also be considered as a form of ‘unconscious bias’?
Let’s get deeper inside this topic and find out whether and how technologies can serve as tools to diminish recruitment bias.
Common types of unconscious bias in recruiting
The way we think and make decisions is largely predetermined by a variety of unconscious biases and unfortunately, recruitment appears to be one of the most biased spheres. The challenge is that bias often happens despite our desire or intent and finds its representations in various forms. Some common types of bias include:
1. Confirmation bias
Recruiters tend to make decisions based on what they identify with and are biased towards favouring. For instance, a recruiter could form an opinion based on the college or university the candidate attended, leading to a candidate being considered as more or less competent before the actual interview takes place.
60% of interviewers will make a decision about a candidate’s suitability within the first 15 minutes. Further on into the hiring process, the recruiter is simply trying to justify their decisions.
2. Affect heuristics
This type of bias relates to situations when the decision is made based on superficial factors. Thus, HR may regard a candidate as incompetent because of some trait which is not meaningful to the role in question at all (e.g. tattoos can deter recruiters from choosing entirely suitable candidates).
3. Expectation anchors
An expectation anchor is a piece of information about the candidate or a single trait that plays an inappropriately decisive role in the recruitment decision - typically something that bears little relevance to the professionalism and competency of the candidate.
In such cases, the interviewer will typically focus on a small number of specific factors that skew the interviewer’s expectations of the candidate and their consideration of the candidate’s suitability for the position.
4. Halo effect
This type of bias functions similarly to an expectation anchor. The key difference, in this case, is that HR usually concentrates on a particular positive fact or trait. For instance, physically attractive people are more likely to get a position and formally dressed candidates can create an impression of having more competency for the role. In addition, positive feedback about the candidate before the interview can create a halo lens for an interviewer.
5. Horn effect
This one is opposite to the halo effect, with the difference that HR concentrates on negative facts or traits and lets these drive the hiring decision. In this case, the interviewer might judge a person and attribute negative qualities to them based on one known stereotyped quality: for example, that untidy clothing or shoes reveal insufficient organisational skills, where in fact the person may be highly organised in how they approach their workload.
This type of bias is the most widespread and well known. Strangely enough, it is often perceived as a positive and even valuable characteristic of HR. However, by trusting your gut instead of comparing candidates based on a range of factors, you may be making poor decisions.
7. Illusory correlation
Illusory correlation is a strong belief in the relationship between variables, even when the relationship is only correlational and not causational.
Unconscious bias is complex and exists in various forms; the human cognitive process is inherently vulnerable to being affected by bias. All the biases listed above relate to 5 general groups according to what mental activity they are relate to:
Why should unconscious hiring bias worry you?
Hiring bias is a serious problem both for employers and employees. Like any other problem, it has its cost, and this cost can be considerable, as much as when you make compromises on recruitment candidates. Frankly speaking, hiring bias is costing you:
The average cost per hire for companies is £3,000. Unconscious bias can cause hiring the wrong people or result in low retention rates among the newly employed. Find out more about the obvious and hidden costs of recruiting in this article on types of HR costs.
Global Recruiting Trends report that “78% of recruiters and hiring managers say that diversity is the top trend impacting how they hire.” Unconscious bias seriously affects workforce diversity which, in turn, hinders overall productivity.
Related article: Managing diversity in the workplace
Technology use cases in diminishing recruitment bias
Taking recruitment decisions requires judgments based on data and various implicit concepts and evidence. Despite initial doubts, modern AI-powered solutions do show promise as one of the most reliable tools.
Algorithms have proved their efficiency in removing bias as they successfully disregard age, name, race, or gender variables. Keep in mind, though, that the actual root of bias in AI is the very human behaviour and mistakes the AI is designed to learn from.
Let’s consider the real AI use cases for diminishing recruitment bias.
Sourcing and screening decisions based on data points
AI-powered solutions allow candidate screening according to numerous data features. By combining various data points these tools make predictions on the best fitting candidates.
Application Tracking Systems (ATS), for instance, can filter resumes for the team. ATS software can reduce bias due to its specific features:
- Anonymous feedback (automatic segregation of the feedback into positive and negative with no reference to its author)
- Collaborative recruiting (online sharing of comments and notes for every candidate, creating an interview history)
- Generalised filters (automatic filtering free from biases, assumptions, and mental fatigue)
- Data hiding (hiding the data that may cause bias via query design)
A major benefit, in this case, is that the results may be easily tested and validated. However, the final decision always depends on you.
Ignoring information about candidates
Another important feature of AI-powered solutions is that they may be programmed to ignore particular data concerning candidates. Thus, such details as age, gender, demographic data, and race may be ignored to reduce bias.
The interview is one of the manager stages of the recruitment procedure. Thus, to make this process as objective as possible the interview structure should also involve the application of modern digital tools. Using standardized questions, digitized aptitude testing systems, and AI-powered solutions for data processing helps to eliminate bias and make the process more transparent.
Unconscious bias is natural and it will always exist. For the moment there is no single solution to remove it once and for all. However, it does not mean we cannot minimise it. Thanks to modern technological advancements and approaches, recruiting teams can enhance their objectivity and make better hiring decisions.
Read more from our blog
Written by Erika Rykun
Erika is a career and productivity copywriter who believes in the power of networking. In her free time, she enjoys reading books and playing with her cat Cola.


International Women’s day is a celebration of what women have achieved and how far they have come. Aboriginal women had twice as far to travel with more hurdles than you see in the Olympics. We were over looked, the white colonizers treated us worse than our men. We had to fall into the structures of a male dominated society and that completely ignored our role in the Aboriginal community and the family. We encouraged and helped our white sisters in their push for equality, the shame being that they didn’t support us. The Feminist movement did nothing to help Indigenous or Black women around the world. They used us like steps on a ladder to push their own agenda.
But Our women were always feminists. Traditionally we didn’t see women as the property of men, they were not subservient. The man wasn’t the head of the family. We had a system that recognised the importance of both male and female. We have been trying to reclaim that after the missionaries and early settlers pushed their patriarchal system and ideals on us. Having our women recognised as equal is still foreign to white Australia. It doesn’t recognise the importance of two people male and female representing us on all levels.
In the hospital system it is important to have male Aboriginal hospital liaison officers to work with our men and female ones to work with the women. The same goes for everything we do. Don’t ask a woman about men’s business, she won’t tell you, she can’t tell you. The same with men talking women’s business.
Because we value the strength and knowledge of women we have been putdown and demeaned by the wider Australian community. We were told in one period of oppression that our men had problems with alcohol and drugs because we were not in a hunter gatherer society anymore and that women do more than they used to in traditional society and usurped our men. Luckily we saw through this and know it for an attack on us, rather than look at the big picture of what is going wrong.
Our women hold together our families and communities. We need to celebrate our women and rejoice that we have so many strong young women coming up who will replace our Elders. Our women hold the spirit of our culture. Show your love and appreciation to the Strong Black women this International Women’s Day


A searing, kaleidoscopic portrait of Bangladesh from the 1947 Partition to the present
Bangladesh was once East Pakistan, the Muslim nation carved out of the Indian Subcontinent when it gained independence from Britain in 1947. As religion alone could not keep East Pakistan and West Pakistan together, Bengali-speaking East Pakistan fought for and achieved liberation in 1971. Coups and assassinations followed, and two decades later it completed its long, tumultuous transition to parliamentary government. Its history is complex and tragic—one of war, natural disaster, starvation, corruption, and political instability.
First published in India by the Aleph Book Company, Salil Tripathi’s lyrical, beautifully wrought tale of the difficult birth and conflict-ridden politics of this haunted land has received international critical acclaim, and his reporting has been honored with a Mumbai Press Club Red Ink Award for Excellence in Journalism. The Colonel Who Would Not Repent is an insightful study of a nation struggling to survive and define itself.


Photo © Shutterstock
A group of South Korean scientists have developed a microscopic robot that can both detect and treat cancer. The nanorobot is powered by a special, genetically-modified bacteria that can detect substances and proteins associated with cancer growth. Once it reaches a cancer cell, the 3-micrometer robotic device automatically sprays anticancer drugs. The robot opens the doors for a more targeted approach to fighting cancer, which is likely to have fewer side effects than conventional treatments like chemo or radiation, which attack the entire body.
Photo © Scientific Reports
Unfortunately, the device has some serious limitations. It can currently only detect solid cancers, such as breast or colorectal cancer. The developers are hoping to advance the technology further so that it can detect more types of cancer in earlier stages. The scientists have already patented their nanorobot in the U.S., Japan, and all members of the EU, although for now human trials look to be far off. They’ve published their findings in the latest edition of the online journal Scientific Reports.
Via Yonhap News


Walk by a bakery, and you’ll smell fresh-baked bread. But would you smell it, if you’d never learned what bread was? “Not necessarily,” says Thomas A. Cleland, Psychology.
“The very concept of having odors that you recognize and identify, even being able to pick them out of the messy olfactory world out there, absolutely depends on learning,” says Cleland. “I argue that learning is fundamental to even being able to smell at all.”
It seems counterintuitive—if the molecules exist, shouldn’t we be able to detect them? “But your brain lies to you for your benefit,” Cleland says. “It doesn’t give you a literal, accurate representation of the world but an improved one for your purposes, which your evolutionary history and brain have decided for you.”
In the visual system, for example, mechanisms within the retina sharpen images, allowing us to better distinguish edges and objects. “Your visual sense will also embed these priors—ways of thinking or expectations—into visual perception,” Cleland says. In other words, your visual system is making things easier for you, by making reality seem clearer than it actually is.
Cleland is proving the same thing to be true in the olfactory system—that these mechanistic enhancements and learned expectations are essential to identifying odors. For a sensory system that was once seen as rather simple, many big, new, and complex questions follow: How and where does this learning happen? What are the olfactory mechanisms of learning and memory? Can those mechanisms tell us anything about learning and memory elsewhere in the brain?
How the Olfactory System Constructs Odors
The basic mechanism of olfaction may seem straightforward. Molecules bind to receptors, and those receptors send signals to the olfactory bulb, which sends signals to other regions of the brain. But the molecules that make up an odor bind to many different receptors, sometimes weakly or strongly, sometimes changing the configuration of the receptor to block other molecules from binding. With about 400 receptors in humans, and over 1,000 in mice and dogs, the signatures for certain odors become complex and high-dimensional.
Even more importantly, Cleland says, these signatures are almost never going to be in isolation from the continuous flow of molecules in the environment. Therefore, the patterns of receptor binding are extremely messy—patterns disrupt and get in the way of each other and do not resemble the characteristic signature of any particular odor. “I think this is the most important problem in olfaction,” says Cleland. “How can the system do this impossible thing of prioritizing and interpreting? But the very early circuitry in the system is giving us clues.
“What we think that the first couple of layers of the olfactory system do is to build odors and define their sort of fuzzy boundaries,” Cleland continues. “You get this messy input, and the perceptual system in your brain tries to match it with what you know already, and based on what you expect the smell to be. So the system will suggest that the smell is X and will deliver inhibition back, making it more like X to see if it works. Then we think there are a few loops where it cleans up the signal to say, ‘Yes, we’re confident it’s X.’”
This system allows animals to identify important odors and ignore unimportant ones. It enables clear distinction between almost identical odors when it matters most. Mice, for instance, can identify the dominant among them by their individual odors, even though they all smell like mice. “The olfactory bulb can take things that are very similar and move them apart by accentuating those differences and by identifying the really important distinctions,” Cleland says.
Therefore, what we end up smelling is a complex conversation between the chemical properties of a smell, what we might have been expecting, and what we already recognize. In other words, the discrete odor that we perceive is a product of our ability to categorize and to learn the categories.
The Chemistry of Memory
If learning is so essential to identifying odors, on a molecular level, how and where is that learning achieved? One way Cleland approaches this question is by tracking the effect and the location, within the brain, of molecules and proteins that turn up when learning happens.
“We’ve long known that learning causes certain molecules to be secreted,” says Cleland. “With short-term memory, synapses change strength and embed some kind of learning. And permanency, long-term memory, requires protein synthesis.”
The secretions and syntheses associated with learning have been observed in many areas of the brain and have been studied most often using fear conditioning—issuing shocks to teach mice models to avoid particular locations, for example. Cleland’s lab is interested in the more gradual learning that happens day to day. In an ongoing collaboration with the lab of Jeffrey A. Pleiss, Molecular Biology and Genetics, the two teams are looking at the brains of dozens of mice that have been trained with rewards to learn about odors over different periods of time, with more selectivity for specific odors or less. “We want to find out, in a big data kind of way, what molecules we should be paying attention to,” Cleland says. “Which RNAs, the things that make proteins, are being overexpressed; what’s the time course for over- or under-expression; and what changes in expression levels are a result of this learning? We want to know the patterns.”
This data, Cleland hopes, will shed light not only on the olfactory system but also may provide insight on how memory and learning works in other areas of the brain.
A Computational Model to Match Biology
Cleland’s team tackles these questions—of how learning really works in animals—using many different methods: by studying behavior and learning in mice models; with biological experiments, sending electrical signals through slices of brain; by optically clearing the brain with the CLARITY method, a new technique that allows Cleland to see a three-dimensional picture of stained, fluorescent molecules in a brain, which is otherwise rendered transparent. One of the most important projects in Cleland’s lab is building computer models of mechanisms within the olfactory bulb as well as a model of the entire olfactory bulb itself.
“What the models do is force us to put all of these things together to say that only one story, albeit a flexible one, can actually match all of these things that we study. So everything has the chance to falsify our story,” says Cleland.
To get an accurate biological picture, Cleland’s models must be as complex as the cells and interactions themselves. One major stumbling block has been that the available computer technology doesn’t allow for quick enough communication between machines to efficiently mimic biology. Cleland and his team have overcome this by building Myriad, a massively parallel simulator using video cards to model large-scale systems with dense analogue connections. They’ll release their simulator to the community for use in 2016-2017.
“I think our work will make this kind of modeling much more doable,” Cleland says. “You can only show what a system is capable of up to the limits of how well you’ve modeled it.”
The uniquely complex modeling that Cleland does also serves as a window into why he ended up studying the olfactory system. “It was my inability to decide between doing something that was high-level interesting but tough to study, like cognition, and something that’s physical, measurable—cold, hard science,” he says. “The olfactory system bridges these two levels. It’s high-dimensional and complex, but you can access it and measure it. Then I knew what I wanted to do. I could see a way that I could have an impact.”


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February 14, 2014
We live at the bottom of an ocean of air. Each of us is carrying around 14.7 pounds per square inch when at the beach in Miami1. We are powerful creatures indeed. Imagine carrying around 101,000 Pascal’s on that beach. Or 1,010 millibars. As elevation increases the weight of the air we are carrying around decreases. This decrease in weight with elevation is called the lapse rate (Figure 1).
Figure 1: Lapse Rate—This is a chart of the U.S. Standard Atmosphere. The “red” line is the temperature lapse rate. The “blue” line is the pressure lapse rate. The pressure lapse rate is around 12 Pa per meter or 3.6 Pa per foot.
The lapse rate thing gets interesting with buildings. In a heated building the lapse rate inside is less than the lapse rate outside. This is due to the reduced density of heated air compared to unheated air. Check out Figure 2. The assumptions in this figure are important. There is only one hole in the building enclosure and it is at the bottom. There are also no interior floors or partitions. So we have an airtight building (except for the one hole at the bottom) with no interior flow resistance. And the building is heated. At the hole the pressure inside equalizes with the pressure outside. As we go up with height the pressure difference between the inside and outside gets bigger. This difference in pressure is called the stack effect.
The stack effect gets its name from the same phenomenon that causes hot combustion gases to rise in a chimney or chimney stack. A heated house or heated building can be considered a giant chimney that we live and work inside of. The taller the building the greater the stack effect. The colder the temperature the greater the stack effect. So, in heated buildings, the air tends to flow out of the top of the building while inducing air to flow in at the bottom.
Now lets look at Figure 3. The hole is at the top of the building. All other assumptions are the same. Once again, at the hole, the pressure inside equalizes with the pressure outside. As we go down in height the pressure difference between the inside and outside gets bigger—but it is in the opposite direction. Neat, eh? The interior pressure line (the interior lapse rate “line”) moves laterally- horizontally - shifts to the left from Figure 2 to Figure 3. The “solid” line does not move. The “dotted” line moves. The slope of the “dotted” line does not change, it just shifts left.
What happens when we have two holes the same size? One at the top and one at the bottom? Check out Figure 4. The “dotted” line shifts right partially. It crosses the “solid” line smack dab in the center of the building elevation wise. Where the interior lapse rate line crosses the exterior lapse rate line the pressure inside equals the pressure outside. No pressure difference exists. We call that the neutral pressure plane or neutral pressure zone. A real smart old guy wrote about this in this Journal in 1926.2
Figure 4: And Still More Stack Effect - Building with no internal separations with openings at the top and bottom (adapted from Handegord, 1998). Beginning to look familiar, eh? Notice the “neutral pressure plane”. At the neutral pressure plane no difference in pressure exists between the inside and the outside.
Now lets modify the assumptions a bit. Lets assume a uniform distribution of leakage areas. All surfaces are uniformly leaky—same size holes—same distribution. Also, and this is the tricky assumption, lets assume “no flow”3. Now let’s put a vented attic on top of the box. We get Figure 5. All holes above the neutral pressure plane would have air “exfiltrating” if there was flow. All holes below the neutral pressure plane would have air “infiltrating” if there was “flow”.
Figure 5: House - Basic two story house with vented attic (adapted from Handegord). The assumption here is a uniform distribution of leakage areas. All surfaces are uniformly leaky. All holes above the neutral pressure plane have air “exfiltrating”. All holes below the neutral pressure plane have air “infiltrating”.
How does the neutral pressure plane know where it is supposed to be? Ah, Grasshopper, it always knows. In the absence of wind and exhaust fans, supply fans and ducted HVAC systems and interior partitions…..weasel words for sure…roughly half the holes are above the neutral pressure plane and roughly half the holes are below the neutral pressure plane. We are talking surface area wise…sort of. There are cracks and there are straight through to the outside holes and there are tortuous paths…It gets worse. Holes farther away from the neutral pressure plane are more “important” than holes closer to the neutral pressure plane. It is sort of like a “moment” calculation in structural engineering. The “effective area” of a hole is multiplied by its distance to the neutral pressure plane and this product is added to the next product of the “effective area” of a hole multiplied by its distance to the neutral pressure plane for all of the holes above the neutral pressure plane. Yes, you all know where this is going…this sum must equal the sum of the same exercise of all of the holes below the neutral pressure plane.
Bottom line: sealing big holes in the attic moves the neutral pressure plane down and sealing big holes in the basement moves the neutral pressure plane up. This has very interesting consequences. Let’s say you want to keep radon gas out of your basement4. Sealing big holes in you attic helps as it lowers the neutral pressure plane and reduces the pressures across the holes at the bottom of your building.
Let’s say you were running an energy conservation program in a country where it is cold and they play hockey outside and you wanted to insulate attics. But when you first just added a bunch of attic insulation you rotted out a whole bunch of attics because you made the attics colder and negated the effect of attic ventilation on controlling attic moisture problems because attic ventilation needs heat loss to work. So you wanted to fix this and you did fix this by sealing the big holes in the ceiling - the “attic bypasses”—to prevent interior moisture laden air from getting into the attic and causing those nasty attic moisture problems. You fixed it by mandating air sealing your attic ceiling as part of your insulation strategy. Guess what happened to the location of the neutral pressure plane? Yup. You lowered it and exposed more of your exterior walls to exfiltration. You just moved the attic moisture problem to your walls. Bummer. It got worse.
Most homes in cold climates were heated with fuel burning furnaces - gas and oil heat. These appliances had chimneys. As far as building enclosures are concerned chimneys are exhaust fans—big ones at that. Exhaust fans and chimneys tend to raise the neutral pressure plane. Most houses in cold climates with big oil and gas furnaces had neutral pressure planes located above attic ceilings (Figure 6). This had enormous implications for building durability.
Figure 6: House With Operating Chimney—The operating chimney depressurizes the house by raising the neutral pressure plane well above the ceiling (adapted from Handegord). It was hard to rot a house in a cold climate that had a neutral pressure plane located above the ceiling. It was hard, but not impossible, you could do it with rain leakage.
With neutral pressure planes located above ceiling lines the entire building enclosure sees infiltration. Infiltrating air does not bring moisture with it in a cold climate during the heating season. Exfiltration hurts you, not infiltration, in a cold climate. And exfiltration hurts you only if the exfiltrating air has lots of moisture in it. It was hard to rot a house in a cold climate that had a neutral pressure plane located above the ceiling5. The old big chimneys did two things—they raised the neutral pressure plane above ceilings and they also provided a large air change that served to dilute interior moisture levels.
Of course the “bad thing” about these old oil and gas furnaces with big chimneys was that they were very energy inefficient. We began to replace them with sealed combustion appliances. We also discovered heat pumps and electric heating. No chimneys. Neutral pressure planes dropped like rocks and dilution air change that came from operating chimneys disappeared. So interior moisture levels went up precisely at the same time large portions of building enclosures became exposed to exfiltrating air.
Getting rid of active chimneys and air sealing attic ceilings dropped neutral pressure planes and caused moisture havoc in cold climate exterior walls (Photograph 1 and Photograph 2). Just by looking at buildings you could often tell where the neutral pressure plane was. Many two story houses had frost on the second floor windows whereas the first floor windows were clear—infiltration through the lower windows and exfiltration through the upper windows—neutral pressure plane between the two.
Photograph 1: Peeling Paint “Tell” - Where is the neutral pressure plane in this photograph? Neat eh? Air exfiltrating above the neutral pressure plane typically carries interior moisture. This moisture is deposited in the wall leading to peeling paint problems. Below the neutral pressure plane air is infiltrating from the exterior carrying little or no moisture. Legend has it that in this building an old oil boiler with a large active chimney was replaced with a sealed combustion condensing gas boiler lowering the neutral pressure plane. Of course, this picture could also be explained by rain deposition, but I am sticking with the air leakage neutral pressure plane story because it is so cool.
Photograph 2: Stack Effect Damage—This is stack effect air leakage leading to moisture induced damage for sure. Not rain. Why? Only happens in winter when it does not rain. Efflorescence. It came from inside and ate your building…. wooo…scary stuff boys and girls…
When we go to high-rise buildings the principles remain the same as do the problems. Stack effect driven airflows in tall buildings compromise smoke control and fire safety, adversely affect indoor air quality and comfort as well as increase operating costs for space conditioning energy (Figure 7). The air in lower units ends up in the upper units. I guess that is why folks in the upper units pay more for the privilege.
Figure 7: Stack Effect in a Tall Building—Stack effect driven airflows in tall buildings compromise smoke control and fire safety, adversely affect indoor air quality and comfort as well as increase operating costs for space conditioning energy. The air in lower units ends up in the upper units. I guess that is why folks in the upper units pay more for the privilege.
By isolating the units from each other and from corridors, shafts, elevators and stairwells stack effect driven interior airflows can be controlled (Figure 8). Today we call this compartmentalization. The most elegant argument for compartmentalization of tall buildings came from Handegord (2001).
Figure 8: Compartmentalization— Basically, you turn a ten story building into ten one story buildings that are stacked on top of one another. By isolating the units from each other and from corridors, shafts, elevators and stairwells stack effect driven interior airflows can be controlled.
Achieving compartmentalization is not easy. You have to think 3 dimensionally and treat your interior walls like exterior walls (Figure 9). Back in the day some of us guessed at what unit air tightness should be. I proposed a minimum resistance or air permeance of 2.00 L/(s•m2) @ 75 Pa (Lstiburek, 2005). It seems to be working. This level of unit air tightness is necessary to control stack effect air pressures and to limit airflow from adjacent units and cross contamination.
Figure 9: More Compartmentalization—You have to think 3 dimensionally and treat your interior walls like exterior walls. A minimum resistance or air permeance of 2.00 L/(s.m2) @ 75 Pa of unit air tightness is necessary to control stack effect air pressures and to limit airflow from adjacent units and cross contamination.
Let’s say you achieve compartmentalization. You are not done. Now the mechanical engineer can screw it all up by running ducts and shafts vertically. No central systems. You can’t make that work. You need to keep the ducts within each compartment and vent directly to the exterior (Figure 10). No complaints from you architects about penetrations being ugly. Just deal with it.
Figure 10: Unit Ventilation—Do not run ducts and shafts vertically. No central systems. You can’t make that work. You need to keep the ducts within each compartment and vent directly to the exterior. No complaints from you architects about penetrations being ugly. Just deal with it.
The compartmentalization principle can also be extended to heating, cooling and domestic hot water. Unit space heating and cooling and hot water is provided by individual mechanical systems located in each unit (Figure 11).
Figure 11: Space Conditioning and Hot Water—The compartmentalization principle can also be extended to heating, cooling and domestic hot water. Unit space heating and cooling and hot water is provided by individual mechanical systems located in each unit.
Rooftop penetrations are collected and located in “doghouses” minimizing penetrations. All cable, duct and pipes are run through walls of “doghouses” (Photograph 3). The “doghouse” lids are removable allowing for access.
Photograph 3: Distributed Mechanical Systems—This is why the Gods of Building Science invented flat roofs: a place to stash mechanicals. Rooftop penetrations are collected and located in “doghouses”—all cable, duct and pipes are run through walls of “doghouses”.
So at the end of the day how do things stack up for us? In houses we have learned to live with lower neutral pressure planes by designing and constructing walls to be more moisture tolerant and we have learned to compensate for the lack of active chimney induced air change by providing controlled ventilation systems. In tall buildings we are learning to compartmentalize and to provide distributed ventilation, distributed space conditioning and distributed hot water. Carrying around the weight of that ocean of air doesn’t seem so difficult any more.
Emswiler, J.E.; The Neutral Zone in Ventilation, ASHVE Journal, Vol. 32, 1926.
Handegord, G.O. “Building Science and the Building Envelope”, Handegord and Company, 1998.
Handegord, G.O. “A New Approach to Ventilation of High Rise Apartments” Proceedings of the Eighth Conference on Building Science and Technology, Ontario Building Envelope Council, Toronto, Ontario, February, 2001.
Lstiburek, J.W. “The Pressure Response of Buildings” Thermal VII, ASHRAE/DOE/BTECC, December 1998
Lstiburek, J.W. “Understanding Air Barriers” ASHRAE Journal, July 2005.
Lstiburek, J.W. “Multifamily Buildings” ASHRAE Journal, December 2005.
- Why Miami? Ah, I am thinking warm thoughts. Any sea level location would have worked. Unfortunately the International Civil Aviation Organization (ICAO) Standard Atmosphere assumes a temperature of 15 degrees C (59 degrees F). Not exactly bathing suit weather except for Canadians. It also assumes no water vapor. So it is a “dry cold”…
- No, I never met Professor Emswiler. Not even I am that old. Check out the reference at the end of this column. University of Michigan lad. Go Wolverines. Professor Emswiler also wrote a classic text on thermodynamics amazingly enough called “Thermodynamics”.
- Don’t bust my chops on this ok—actual flow will result in modified pressures—there is friction and a bunch of other stuff to consider—these types of diagrams represent the maximum theoretical pressures. If you want to go into the weeds get the original paper or even better read Handegord—see reference at end of this column. ASHRAE Fundamentals is good too. Or go take Collin Olson of the Energy Conservatory to lunch.
- For many years I have thought that the EPA placed a misguided emphasis on radon mitigation—but I kept silent—ok, not always—because it had a fabulous collateral outcome of handling soil gas and pesticide and ground contamination issues which in my opinion where much more significant to deal with. If you can measure stuff you can scare the peasants. Radon was easy to measure and the radiation thing was so Sci Fi and easy to relate to every pseudo disease.
- It was hard, but not impossible, you could do it with rain leakage.
- Make no mistake about this—I was channeling Gus—this is not my stuff—I just grabbed onto it earlier than most. Gus was on to this very early, he just didn’t always write things down and get them published and peer reviewed in a timely fashion. He finally wrote it all down in his 2001 paper but I first heard it from him when I took his class at the University of Toronto in 1982 and he was talking about it much earlier than that. I was pushing compartmentalization when I first started working in the United States in 1986. I still smile when I remember the arguments with the Chicago high-rise boys in the late 80’s.


If you’re looking to reduce your stress levels, blocking some of your blood vessels may just be the answer. By reducing the amount of oxygen and blood that is available to your brain, you can reduce your stress levels by reducing the amount of information your brain is processing.
How blocking blood vessels can help reduce stress.
Blocking blood vessels can be a simple way to reduce your overall stress levels. By reducing the amount of oxygen and blood that is available to your brain, you can help relieve some of the pressure that is building up. Additionally, blocking blood vessels can provide short-term benefits such as reducing stress levels.
The benefits of blocking blood vessels.
There are numerous benefits that can be derived from blocking blood vessels. By doing this, you can reduce your stress levels by reducing the amount of oxygen and blood that is available to your brain.
Some of the benefits of blocking blood vessels include:
a. Reduced stress levels
b. Improved focus and concentration
c. Increased energy Levels
d. Enhanced moods
e. Better sleep
f. Reduced anxiety and panic attacks
g. Even better health overall
Blocking blood vessels is a simple and easy way to reduce your stress levels, and the benefits are numerous and long-lasting. If you’re feeling overwhelmed or stressed out, give blocking blood vessels a try – you won’t regret it!
The types of blood vessels that can be blocked.
There are a variety of different blood vessels that can be blocked. Some of the most common blood vessels that can be blocked are the arteries and veins. Different methods can be used to block different types of blood vessels. The benefits of blocking blood vessels vary depending on the type of blood vessel that is blocked. The steps necessary to block blood vessels vary depending on the type of blood vessel that is blocked. The benefits of blocking blood vessels usually last for a period of time, but vary depending on the person. Possible side effects of blocking blood vessels include pain, difficulty breathing, and bruising.
The steps necessary to block blood vessels.
Block your blood vessels by following these simple steps:
1. Find a comfortable position.
2. Place your hands on your abdominal area just below your chest.
3. Inhale and exhale deeply, making sure to fill your lungs with air.
4. Concentrate on your breathing, and allow yourself to relax.
5. Now, imagine a narrow band of energy wrapping around your entire body, from head to toe.
6. Keep this energy focused on your ankles, and allow it to flow up your legs and out through your feet.
7. Once the band of energy has left your body, repeat steps 1-6 for the other side.
Following these steps will help you achieve several benefits:
1. You will feel more relaxed and stress free.
2. You will be able to reduce the amount of stress that you experience each day.
3. The benefits of blocking blood vessels will last for a short period of time, but you can extend the duration of the benefits by repeating the steps.
How long the benefits will last.
The benefits of blocking blood vessels will last for a short period of time. The effects of using them will typically last for around twenty minutes, but they may last up to an hour or more. However, the benefits of blocking blood vessels do wear off over time, and they should be used sparingly so that the effects last as long as possible. Some possible side effects of using blood vessel blockers include dizziness, lightheadedness, and headaches.
Possible side effects of blocking blood vessels.
When you block blood vessels, you reduce the amount of oxygen and blood that is available to your brain. This can lead to a number of different side effects, some of which are more severe than others.
Some of the side effects that can occur when you block blood vessels include decreased blood flow, lightheadedness, and blurred vision. These side effects can vary depending on the type of blood vessel that is blocked, but they all tend to be milder than the side effects that would result if the blood flow remained unrestricted.
It is important to speak with a doctor before attempting to block blood vessels as some side effects may be more severe than others. In addition, always be aware of the possible side effects of blocking blood vessels, and if you experience any problems, speak with a doctor immediately.
By reducing your stress levels by blocking some of your blood vessels, you can reduce the amount of oxygen and blood that is available to your brain. The benefits of blocking blood vessels last for a short period of time, but there are possible side effects to consider.
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.. Talking of birds, all through the Peruvian and Bolivian Montana is to be found a small bird like a kingfisher, which makes its nest in neat round holes in the rocky escarpment above the river. These holes can plainly be seen, but are not usually accessible, and strangely enough they are found only where the birds are present. I once expressed surprise that they were lucky enough to find nesting-holes conveniently placed for them, and so neatly hollowed out - as though with a drill.
"They make the holes themselves." The words were spoken by a man who had spent a quarter of a century in the forests. "I've seen how they do it, many a time. I've watched, I have, and seen the birds come to the cliff with leaves of some sort in their beaks, and cling to the rock like woodpeckers to a tree while they rubbed the leaves in a circular motion over the surface. Then they would fly off, and come back with more leaves, and carry on with the rubbing process. After three or four repetitions they dropped the leaves and started pecking at the place with their sharp beaks, and - here's the marvellous part - they would soon open out a round hole in the stone. Then off they'd go again, and go through the rubbing process with leaves several times before continuing to peck. It took several days, but finally they had opened out holes deep enough to contain their nests. I've climbed up and taken a look at them, and, believe me, a man couldn't drill a neater hole!"
"Do you mean to say that the bird's beak can penetrate solid rock?"
"A woodpecker's beak penetrates solid wood, doesn't it? ...No, I don't think the bird can get through solid rock. I believe, as everyone who has watched them believes, that those birds know of a leaf with juice that can soften up rock till it's like wet clay."
Another friend of mine told me the following story:
"Some years ago, when I was working in the mining camp at Cerro de Pasco (a place 14,000 feet up in the Andes of Central Peru), I went out one Sunday with some other Gringos to visit some old Inca or Pre-Inca graves - to see if we could find anything worthwhile. We took our grub with us, and, of course, a few bottles of pisco and beer; and a peon - a cholo - to help dig.
"Well, we had our lunch when we got to the burial place, and afterwards started in to open up some graves that seemed to be untouched. We worked hard, and knocked off every now and then for a drink. I don't drink myself, but the others did, especially one chap who poured too much pisco into himself and was inclined to be noisy. When we knocked off, all we had found was an earthenware jar of about a quart capacity, and with liquid inside it.
" 'I bet it's chicha! said the noisy one. 'Let's try it and see what sort of stuff the Incas drank!'
" 'Probably poison us if we do,' observed another.
" 'Tell you what, then - let's try it on the peon!'
"They dug the seal and stopper out of the jar's mouth, sniffed at the contents and called the peon over to them.
" 'Take a drink of this chicha,' ordered the drunk. The peon took the jar, hesitated, and then with an expression of fear spreading over his face thrust it into the drunk's hands and backed away.
" 'No, no, senor,' he murmured. 'Not that. That's not chicha!' He turned and made off.
"The drunk put the jar down on a flat-topped rock and set off in pursuit. 'Come on, boys - catch him!' he yelled. They caught the wretched man, dragged him back, and ordered him to drink the contents of the jar. The peon struggled madly, his eyes popping. There was a bit of a scrimmage, and the jar was knocked over and broken, its contents forming a puddle on the top of the rock. Then the peon broke free and took to his heels.
"Everyone laughed. It was a huge joke. But the exercise had made them thirsty and they went over to the sack where the beer-bottles lay.
"About ten minutes later I bent over the rock and casually examined the pool of spilled liquid. It was no longer liquid; the whole patch where it had been, and the rock under it, were as soft as wet cement! It was as though the stone had melted, like wax under the influence of heat."
Originally posted by kdog1982
We have now found out what the plant is, what the leaf is, and it’s quite well known. It’s a very common plant. As a matter of fact, we use it for ornamental purposes. You can buy it in the stores, in a florist’s in New York. The Latin name escapes me, but its got ordinary sort of rather spongy-looking red leaves–it’s red and purple instead of being green. It has a substance in it that is a very strong alkali and not an acid.
Originally posted by reticledc
If it softens rock, then why not the bird's beaks?
Is it that specific that it will only soften rock?


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habitat of small cardamom is the evergreen forests of
Western Ghats. It is grown in areas where the annual
rainfall ranges from 1500-4000 mm with a temperature
range of 10-35 ºC and an altitude of 600-1200 m
is generally grown in forest loam soils rich in available
phosphorus and potassium. The crop is raised mainly
on well drained, deep, good textured soils rich in humus.
Ripe capsules of the desired cultivar are collected
from high yielding plants during September-October.
The seeds are extracted by gently pressing the capsules.
In order to increase the germination percentage, seeds
can be treated with concentrated sulfuric acid or nitric
acid for not more than two minutes. The extracted seeds
are washed in cold water four times to remove the mucilaginous
coating. The washed seeds are drained and mixed with
ash and allowed to dry in shade for 2 or 3 days. The
seeds should be sown in the nursery within a fortnight.
Sowing in September is the best for high germination.
Sowing during southwest monsoon and winter should be
it becomes necessary to store the seeds, it is advisable
to store them in capsule form. It can be preserved in
this form for one month, without deterioration of viability.
Polythene lined gunny bags can be used for this.
Kerala and Tamil Nadu, 18 month old seedlings are used
for planting. The seeds are sown in primary nursery
from where the young seedlings are transplanted to a
secondary nursery and maintained for one year before
planting in the main field.
The nursery site is selected in open, well-drained areas,
near a source of water. The land is dug to a depth of
30 cm, cleared of all stubbles and stones; and clods
are broken. Beds of size 6 x 1 x 0.3 m are then prepared.
Jungle soil is spread in a thin layer over the nursery
bed. Seeds are sown on the bed in lines. For an area
of 1 m2, 10 g of seed is required. Sixty grams of seeds
will be required for a nursery bed of 6 m2. The seeds
are covered with a very thin layer of fine soil. The
nursery bed is mulched with dry grass. Potha grass (Grenetia
stricta) commonly seen in high range areas is a suitable
material for this purpose. Grass is spread to a thickness
of about 2 cm. Paddy straw can also be used for mulching.
After sowing, beds have to be watered every day in the
morning and evening. The mulch should be removed on
commencement of germination. The seedlings have to be
protected by providing shade pandals. Regular watering,
weeding and protection from pests and diseases are to
be attended to. During June-July, seedlings from the
primary nursery are transplanted to the secondary nursery.
After preparing the site properly, form nursery beds
of 6 x 1 x 0.3 m. Mixing of well decomposed cattle manure
and wood ash with the top layer of the soil will help
the seedlings to establish well and to grow vigorously.
During June-July, the seedlings from the primary nursery
are transplanted at a spacing of 25-30 cm. Shade pandals
should be provided before transplanting. Overhead pandals
or individual pandals for each bed may be erected. Mulching
the bed with dry leaves will help to conserve soil moisture.
Regular watering during dry months, weeding, application
of fertilizers, control of pests and diseases and mulching
are the essential operations for the maintenance of
the secondary nursery. One month before uprooting, the
pandal should be removed to encourage better tillering.
Polybags can be used for raising secondary seedlings.
For such nurseries, seeds are to be sown in beds in
primary nurseries in September and transplanted to polybags
in December-January. These seedlings would be ready
for planting in June-July. In this case, nursery period
could be reduced by 6 to 7 months.
This may be taken up from the first week of March to
the first fortnight of October. The site is selected
in open, gently slopping and well-drained areas near
a source of water. Trenches of 45 cm width, 45 cm depth
and convenient length are taken across the slope or
along the contour 1.8 m apart. They are filled with
equal quantity of humus rich topsoil, sand and cattle
manure. Uproot a part of the high yielding disease free
mother clump identified in the plantation. Trim the
roots and separate the suckers so that the minimum planting
unit consists of one grown up tiller and a growing young
shoot. Plant them at a spacing of 1.80 m x 0.60 m in
filled up trenches. Provide sufficient mulch and stake
each planting unit. Provide overhead pandal as in the
case of seedling nursery and remove shading material
with onset of monsoon rains. Provide irrigation once
in a fortnight and adopt necessary plant protection
measures. Apply fertilizers @ 100:50:200 kg/ha N:P2O5:K2O
in six splits at an interval of two months. Apply neem
cake @ 100-150 g/plant along with fertilizers. On an
average, 20 to 30 suckers / initial planting unit can
be produced within one year of planting. Care should
be taken to identify and collect mother clumps only
from areas totally free from 'katte' disease.
treatment in nursery
It is recommended that the primary and secondary nursery
soil may be drenched with formalin 2% solution and covered
with polythene sheets for 3 days. Planting should be
taken up only 15 days after treatment to avoid phytotoxicity.
Since inadequate as well as excessive levels of shade
are harmful to the crop, regulation of shade is inevitable.
There should be sufficient shade to protect cardamom
plant during the hot season. By regulating the shade
before the monsoon, more light becomes available to
the plant during the rainy season. Red cedar or chandana-vempu
(Toona ciliata) is an ideal shade tree. It sheds the
leaves during rainy season and thus provides natural
shade regulation. Some of the other shade trees are
kurangatti (Acrocarpus fraxinifolius), vellakil (Dysoxylum
malabaricum) and thelli (Canarium strictum).
ICRI-2, PV-1 and PV-2.
Malabar: Suitable for areas from 600 to 1200 m elevation
Mysore: Suitable for areas from 900 to 1200 m elevation
Vazhukka: Suitable for areas from 900 to 1200 m elevation
Cardamom can be propagated vegetatively and by seedlings.
For vegetative propagation, rhizomes with not less than
three shoots are used. Plants propagated vegetatively
come to bearing one year earlier than the seedling-propagated
plants. But this method has the disadvantage of spreading
the `katte' disease, which is of viral origin. This
disease is not transmitted through seeds. Hence in areas
where the disease is widespread, it would be safer to
use seedlings for propagation.
Main field planting
Cardamom plantation is raised in forests under the shade
of tall trees. For raising a new cardamom plantation,
the undergrowth of bushes is cleared. When open areas
like marshy valleys and grasslands are selected for
raising new plantation, shade trees have to be raised
before planting cardamom seedlings. The quick growing
shade trees like dadap (Erythrina lithosperma) is generally
used for this purpose. Cuttings of this tree are used
for planting. But this tree is a host of root knot nematode,
which infests cardamom. Other quick growing trees like
Albizia can also be used. Useful trees like jack and
eucalyptus can be used along with red cedar, wild nutmeg,
and Vazhukka: 2 x 2 m to 3 x 2 m depending on the fertility
of the soil
Malabar: 1.5 x 1.5 m to 2 x 2 m depending on the fertility
of the soil.
recommended size of pits is 60 x 60 x 35 cm. The pits
are filled with rich topsoil at least two months in
advance of planting the seedlings. Application of well
decomposed FYM or compost or leaf mould and 100 g of
rock phosphate with the topsoil in the pit will help
in proper establishment and quick growth of plants.
If the selected site is a hill slope, terraces may be
formed before digging pits.
can be done with the commencement of southwest monsoon,
before the heavy rains. A small pit may be formed inside
the pit by scooping out soil at the centre of the pit
for planting seedlings. The soil may be put just to
cover the rhizomes. Care should be taken to ensure that
the rhizomes do not go deep into the soil.
A regular schedule of cultural practices consisting
weeding, mulching, trashing, shade regulation, fertilizer
application, irrigation, etc. will have to be undertaken.
mulch should be applied at the base of the plant during
December to reduce the ill effects of drought during
summer months and to conserve soil moisture. Sickle
weeding is essential which has to be carried out frequently
depending upon the intensity of weeds. Forking is necessary
in hard soils, which is to be carried out in October-November.
(removal of old and dried shoots, leaves and dried panicles)
should be taken up once in a year during June-July,
with the commencement of monsoon. This will help to
prevent the spread of diseases and expose the panicles
to easy visit by honeybees.
Soil conservation measures, maintenance of drainage
channels and such other operations may be taken up promptly.
Bee-keeping for better pollination
The main pollination agent in cardamom is honeybee (Apis
cerana indica). Maintaining four bee colonies per hectare
during the flowering season is recommended for increasing
fruit set and production of capsules.
of organic manures such as FYM, cowdung or compost @ 5
kg / plant or neem cake @ 1-2 kg / plant may be done during
June-July. The present recommendation of nutrients for
cardamom in Kerala is N:P2O5:K2O @ 75:75:150 kg/ha. The
fertilizers may be applied in two split doses, before
and after the southwest monsoon, in a circular band of
20 cm wide and 30-40 cm away from the base of the clumps,
and mixed with soil.
of pests and diseases in the nursery
Rhizome weevil (Prodioctes haematicus)
This is a serious pest in the secondary nursery especially
where seedlings are raised continuously year after year.
The grubs feed on the rhizome and basal portion of the
stem. This results in drying of leaves and breaking of
stem at the base. Drenching the nursery beds with chlorpyrifos
at 0.04% can control the pest.
fly (Formosina flavipes)
The pest is observed in the nursery during January to
May. Dead heart or decay of the central spindle is the
external symptom. Spraying of quinalphos 0.025% or application
of phorate granules @ 1 g ai/m2 is recommended for the
control of the pest.
borer (Conogethes punctiferalis)
The caterpillar bores into the stem and feeds on the
internal contents. This results in the decay of the
central spindle and production of dead heart. Faecal
matter of the caterpillar can be seen coming out through
the holes. Spraying with quinalphos 0.025%, carbaryl
0.1%, monocrotophos, fenthion or dimethoate at 0.05%
or phenthoate at 0.1% is recommended against
the shoot borer.
Nematodes are observed as serious pests in cardamom
nurseries. Roots of cardamom seedlings are infested
mainly by root knot nematode (Meloidogyne incognita).
Lesion nematodes (Pratylenchus) are also seen in cardamom
roots and soils. The main symptoms of nematode infestation
are galls on the root tips, profuse tillering, stunted
and weak tillers, yellowing and drying of leaves and
production of narrow, brittle and abnormal leaves. Treatment
of soil as detailed above is an effective method to
of primary and secondary nursery beds with methyl bromide
is another effective method for the control of nematodes
in the nursery. Five hundred gram of methyl bromide
is required for 10 m2 area. The treated area has to
be kept covered with polythene sheet for two to three
days. Pruning of infested roots tips before planting
is also recommended.
the plants in the nursery with carbofuran @ 5 kg ai/ha
after 10 days of germination and this is repeated after
3 months. In secondary nurseries, the plants may be
treated with carbofuran @ 10 kg ai/ha after transplanting
and every three months thereafter.
Control of pests and diseases in the plantation
thrips (Sciothrips cardamomi)
This insect is a serious pest of cardamom. It colonizes
and breeds in unopened leaves, leaf sheath, flower bracts
and flower tubes. It lacerates and feeds on the exuding
sap from the aerial parts. Infestation on the panicle
and flower buds results in stunted growth of panicles,
shedding of flower buds and warty growth on the surviving
capsules. The infested capsules are light in weight,
inferior in quality and fetch very low price in the
market. Since the pest population is high during dry
months from December to May, pesticide application during
this period is important. Four sprayings or dusting
of insecticide during this period is recommended. Insecticide
application can be skipped during rainy months of June
and July. Three more sprayings are to be given during
the period from August-November. Any of the following
insecticides are recommended for thrips control.
formulations: Quinalphos 0.025%, fenthion 0.03%, phenthoate
0.03%, phosalone 0.05%, monocrotophos 0.025%, fenitrothion
0.05%, formothion 0.03%, dimethoate 0.05%.
formulation: Quinalphos 1.5%, carbaryl 10%, phosalone
4% or phenthoate 4% each at 25 kg/ha
borer (Conogethes punctiferalis)
It is a serious problem to cardamom growers of Kerala,
Tamil Nadu and Karnataka. At the early stage of the
crop, the caterpillars of this yellow coloured moth
bore into the core of the aerial stem resulting in the
death of central spindle, which appears as characteristic
the time of flowering, when the caterpillars attack
the panicles and spikes it may lead to flower shedding
and drying up of the attacked portions. At a later stage
of the crop, the caterpillars bore into the capsules,
feed on the seeds and make them hollow. The presence
of excreta at the region of attack indicates presence
of the caterpillars in the pseudostem, inflorescence
infestation is pronounced in three seasons viz. January-February,
June and September-October.
stages of larvae bore into the pseudostem and remain
there. Insecticides sprayed at this time may not give
adequate control of the pest. For an effective management
of the pest, the insecticides have to be targeted on
early stages of the larvae, which are usually present
within 15-20 days after adult emergence in the field.
Spraying fenthion 0.05% or monocrotophos 0.05% is recommended
during the months of February-March and September-October.
There are 10 species of caterpillars feeding on cardamom
leaves. Out of these, seven species are hairy and appear
in large numbers during certain seasons causing extensive
defoliation. For controlling the leaf caterpillars,
mechanical collection and destruction and spraying of
any contact insecticide are recommended.
whitefly (Kanakarajiella [Dialeurodes] cardamomi)
It is a serious pest in cardamom growing tracts of Kerala.
The adult is a small soft-bodied insect, about 2 mm
long and having two pairs of white wings. The nymphs
are elliptical and pale green. The nymphs secrete sticky
honeydew, which drops on to lower leaves. On these,
black sooty mould develops, which interrupts photosynthesis
of the leaves.
flies are attracted towards yellow colour. So metal
sheets painted yellow and coated with sticky materials,
such as castor oil or poly-venyl butanol would serve
as traps. By placing such yellow sticky traps between
rows of cardamom plants, population of adults can be
monitored and adults trapped to some extent. Nymphs
are effectively controlled by spraying the lower surface
of leaves with a mixture of neem oil (500 ml) and triton
(500 ml) in 100 litre of water. Acephate 0.075% and
triazophos 0.04% are equally effective. The spray may
be repeated two or three times at 15 days interval.
root grubs (Basilepta fulvicorne)
The grubs of a small, greenish blue beetle cause damage.
The grubs are short, stout, pale white in colour and
often assume a shape resembling 'C', which feeds on
cardamom roots. The symptoms start as yellowing of leaves,
which later result in the drying up and death of the
the beetle with hand nets or sticky traps at the time
of mass emergence (March-April and August-September)
and destroy. Early stages of the grub which are usually
present in soil during May-June and September-October
can be controlled either by drenching chlorpyriphos
0.04% @ 3-4 litre per clump or by applying phorate @
2-4 g ai/ha 10-15 cm around the plant.
scale (Aulacaspis sp.)
This scale insect is found on the lower surface of leaves,
leaf sheath, panicles and fruit stalk. As a result of
damage, capsules get shrivelled, panicles become dry
and the leaves become yellow. The pest is mostly seen
during summer months.
monocrotophos or fenthion @ 0.05 % during the peak season.
Root knot nematodes are the most common nematode species
associated with cardamom plantations. Common symptoms
are necrosis of leaf tips and margins, narrowing of
leaves, thickening of veins, reduction of internodal
length and consequent appearance of leaves as rosette.
Roots branch heavily and galls appear on them. Plant
becomes highly stunted.
change of nursery beds will help to reduce nematode
infection in nurseries. In case of infection in primary
nurseries, application of carbofuran @ 80 g per 6 m2
bed and in secondary nurseries, application of carbofuran
@ 200 g / 6 m2 bed will control the pest. In plantation,
carbofuran @ 60-80 g/plant or 20-40 g of phorate with
300-500 g of neem cake per plant may be applied. Application
may be repeated after three months.
This disease is caused by Pythium vexans and Rhizoctonia
solani. Infection is observed at the collar region. Provide
good drainage, and spray and drench the nursery with 1%
Bordeaux mixture or 0.2% copper oxychloride.
This disease is caused by Phyllosticta elettariae. Pale
specks appear on the leaf lamina, which dry up and become
paper white. Spraying the plants with mancozeb 0.25%
at fortnightly intervals is effective in controlling
other diseases are Sphaceloma leaf spot, Cercospora
leaf spot, rust and sooty mould.
Katte or mosaic
This is a virus disease, which is transmitted by the
banana aphid, Pentalonia nigronervosa. The symptoms
consist of discontinuous stripes of light green colour
running almost parallel to each other from the mid-rib
to the margin of the leaves, which form a mosaic pattern.
On young shoots, such stripes are seen on the leaf sheath
also. The infected clumps will be smaller in size with
of the source of inoculum by destroying infected plants
and destruction of the vector by insecticide application
are effective. Regular application of insecticide against
cardamom thrips controls the aphids also. Avoid using
katte-infected rhizome for planting.
of plants showing symptoms of the disease should be
done promptly once in two months. Removal of all alternate
hosts of virus is also recommended.
This is a fungal disease caused by Phytophthora sp.
occurring during the rainy season. It affects the leaves,
tender shoots, panicles and capsules. On the infected
leaves, water soaked lesions appear first and rotting
and shedding of leaves along the veins occur thereafter.
The infected capsules become dull greenish brown and
decay. This emits a foul smell and subsequently shed.
Infection spreads to the panicles also.
and destruction of the infected parts should be done
as a phytosanitary measure just prior to the onset of
southwest monsoon. Remove the trash (dried leaves and
leaf sheaths) from the basal region of the plant to
the extent possible.
Spray the shoots with 1% Bordeaux mixture with adhesive
(rosin soda or any other sticker) by the commencement
of the monsoon and continue the spraying operation two
or three times up to November-December according to
the intensity of the disease and rainfall. Give a copious
spray to the panicle with 1% Bordeaux mixture @ 3 l/plant
during July-August when the disease intensity is maximum.
can be used along with cowdung for controlling this
rot or rhizome rot
This disease is caused by Pythium aphanidermatum, P.
vexans, Rhizoctonia solani and Fusarium oxysporum. The
affected shoots become brittle and easily break off
from the rhizome at the bulbous base.
with 0.2% copper oxychloride (2-3 litre per plant) and
repeat this two times at monthly intervals.
a bio-control measure, inoculate seedlings with native
arbuscular mycorrhiza, Trichoderma and Pseudomonas fluorescens
at the time of planting in the nursery and main field,
and apply during pre-monsoon period in established plantations
(see the chapter on biocontrol agents against plant
fungus Phaeodactylium venkatesanum causes this disease.
The disease is characterized by the appearance of large
blotches of irregular lesions with alternating shades
of light and dark brown necrotic tissues. This is mainly
observed on mature leaves. On the lower surface of the
lesions ash coloured white superficial growth of the
fungus appears during moist weather conditions.
fungicides, Bordeaux mixture (1%), mancozeb (0.3%) and
carbendazim (0.1%) are effective in controlling the
Chenthal disease is characterized by the appearance
of rectangular linear reddish brown lesions mainly on
the lower surface of the leaves. The lesions are clearly
visible even on dried leaves. The incidence of the disease
appears to be more severe in areas, which do not have
proper shade. Even though Corynebacterium and Colletotrichum
gloeosporioides have been isolated from the infected
leaves, the pathogenicity of these organisms could not
adequate shade is the only measure recommended pending
confirmation of etiology of the disease.
period of insecticide / fungicide
Quinalphos 30 days
Monocrotophos 30 days
Mancozeb 30 days
plants normally start bearing capsules from the third
year of planting. Picking is carried out at an interval
of 30 days. After harvest, cardamom capsules are processed.
capsules with green colour fetch a premium price in
foreign countries. Hence emphasis has to be given on
the preservation of green colour during curing and subsequent
storage. Capsule should be processed within 24-36 hours
after harvest to prevent deterioration. By curing, the
moisture of green cardamom is reduced to 8-12 per cent
at an optimum temperature so as to retain its green
colour to the maximum extent.
season in Kerala is October-February and the peak period
of harvest is September-November.
Capsules are dried directly under sunlight for five to
six days or more. Frequent turning is done. This method
can result in surface blemishes and may not give an attractive
green colour. This method is practiced if the cultivar
yields fruits that turn yellow before they are ready for
picking and where facilities for green curing are not
Processing of capsules is done in specially built curing
houses. The harvested capsules are washed in water to
remove dust and soil particles. Then they are spread
on wire net trays in curing chamber. Burning firewood
in the iron kiln produces heat required for drying.
The heat thus produced is passed through pipes made
of galvanized iron sheets. The process of drying takes
about 18-24 hours, depending on the ambient temperature.
The capsules are spread thinly in the wire net trays
and stirred frequently to ensure uniform drying. They
are initially heated at 50 ºC for the first 4 hours
and heat is then reduced to 45 ºC by opening ventilators
and operating exhaust fans till the capsules are properly
dried. Finally the temperature is raised to 60 ºC
for an hour.
dried capsules are rubbed on wire mesh to remove the
stalk and dried portion of flower from the capsules
and then graded according to size by passing through
sieves of sizes of 7, 6.5, 6 mm etc. The graded produce
is stored in polythene lined gunny bags to retain the
green colour during storage and also to avoid exposure
relatively new innovation in the curing procedure is
blanching by soaking the fruits in 2.0 per cent washing
soda for 10 minutes prior to drying. This inhibits colour
loss during drying operation and extends colour retention
during subsequent storage from three months to ten months.
A proportion of the crop is bleached after sun drying
by exposing the capsules to fumes from burning sulphur
to get uniform colour and appearance. Steeping capsules
in a dilute solution of potassium metabisulphite solution
induces a slight improvement in keeping quality.
Solvent extraction of ground spice yields 10 per cent
oleoresin. Cardamom oleoresin is used for flavouring
food after being dispersed in salt, flour etc. One kilogram
of oleoresin replaces 20 kg ground spice.
seeds / seed powder
Decorticated seeds command a lower price due to rapid
loss of volatile oil during storage and transportation.
Seed powder is marketed to a limited extent.


Lincoln’s stated goal in waging war against the South was to maintain the territorial union of States within the 1787 Constitution, which Southern States had withdrawn from. The South established its own union, sending commissioners to Washington to arrange a settlement of funds due that government and a treaty of peace between the two countries. Lincoln’s refused to see the commissioners and secretly sent an armed expedition to reinforce Fort Sumter, by then a useless fortification as it was within South Carolina’s sovereign territory – and explicitly constructed with funds from all States for South Carolina’s protection.
Even if Lincoln reasoned that South Carolina could not withdraw from the 1787 union and it remained within, waging war against a State was treason as defined in Article III, Section 3 of the United States Constitution.
Locked in a Bloodbath
“Soon after hostilities began, the Model 1861 Springfield rifle, capable of killing fire at a thousand yards, would become standard issue for Union infantry, while Confederate troops were being equipped with small arms equally as good. The result was mass slaughter.
In eight of the first twelve big battles, Confederates assumed the tactical offensive, and lost ninety-seven thousand men in doing so. Altogether, the South suffered 175,000 battle casualties in the first twenty-seven months of fighting, a figure somewhat higher than the entire Confederate military establishment in 1861.
[Grant accumulated] sixty-four thousand casualties during the three months of his sledgehammer Wilderness campaign and taking as the major sign of his victory, in late May 1864, the fact that a battle with Lee’s troops “outside of entrenchments cannot be had.”
Yet the Confederates would remain unbeaten inside their trenches for almost a year more. And, in fact, a better indication of the true tactical situation was the spectacle of Union troops pinning their names to their uniforms shortly before the notorious frontal assault on Confederate positions at Cold Harbor on 3 June so that their corpses might be better identified after the battle.
Unlike their officers, foot soldiers drew an altogether more practical, if less heroic, conclusion as to the tactical significance of new weaponry, and sought cover and defensible positions whenever possible. Thus, by mid-1863 both sides were becoming addicted to trenches . . .
As far as they went, field fortifications were an entirely correct solution to the revolution in small arms, the long-range rifle having roughly tripled the advantage of defense over offense by putting attacking troops under deadly fire almost from the moment they became visible. Yet trenches also prefaced a very static and inconclusive sort of war, as the siege of Richmond-Petersburg indicated. Thus at some point it became necessary for troops to physically overcome opposing trenches.
Cavalry, on the other hand, was deeply and permanently undermined. The fate of the saber charge was epitomized by the deaths of one Major Keenan and his adjutant, who jointly led a column of the Eighth Pennsylvania Horse in a desperate advance against Stonewall Jackson’s victorious infantry at Chancellorsville. Not only did the charge fail miserably, but after the battle the bodies of Keenan and his adjutant were found to have thirteen and nine bullet wounds, respectively.”
(Of Arms and Men: A History of War, Weapons and Aggression, Robert L. O’Connell, Oxford University Press, 1989, excerpts pp. 197-199)


If you're interested in researching a specific group of people, like restaurant managers or crime victims, you need to recruit participants for your study. Calling or mailing letters to random people in the phone book would take ages, since most people you contact won't meet your criteria. The solution is snowball sampling, a practice in which a small group of initial participants help researchers find more participants by accessing their social networks. Snowball sampling is convenient, but has significant limitations.
The biggest advantage of snowball sampling is that it helps researchers find more participants for studies than would be possible by other methods. A researcher hoping to survey business executives, for example, might struggle to convince busy CEOs to take the time to fill out a survey. If the researcher happens to know a particular CEO, however, that executive could contact other people in her social network who hold the same title. Since this technique uses existing social relationships, researchers have a better chance to recruit new participants.
Reaching Hard-to-Find Populations
Snowball sampling is particularly useful for finding participants who meet unusual criteria and are typically hard to locate. For example, a researcher interested in surveying survivors of sexual assault might have a very difficult time finding participants, since many survivors never report their assaults to the police and records are often sealed from the public. However, some sexual assault survivors attend support groups and a researcher in contact with one survivor might be able to use that participant's social network to contact more survivors. This allows a larger sample size than would be available otherwise.
One problem with snowball sampling is that participants' social networks aren't random. As a result, the technique can result in biased samples. In the CEO study, for example, if the first participant recruited happens to work in manufacturing, most of her CEO contacts are likely to also come from the manufacturing sector. Thus, the study could exclude or under-represent CEOs from different industries. Similarly, a sexual assault survivor's social network might be limited to a single geographic area, making it impossible for the researcher to generalize study results to the entire nation.
Research Ethics Issues
Snowball sampling can present significant ethical problems, especially if the research topic is sensitive or personal. For example, many sexual assault survivors are reluctant to talk about their experiences and avoid identifying themselves as survivors. A researcher using snowball sampling can keep participants anonymous in published papers but can't keep participants anonymous from each other since participants have to recruit each other. Some study participants may object to using their social networks in this way, and some potential participants may dislike being contacted for participation.
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