Giant ice sheets in Antarctica behave like mirrors, reflecting the sun’s energy and moderating the world’s temperatures. The waxing and waning of these ice sheets contribute to changes in sea level and affect ocean circulation, which regulates our climate by transporting heat around the planet.

Despite their present-day cold temperatures, the poles were not always covered with ice. New climate records recovered from Antarctica during the recent Integrated Ocean Drilling Program (IODP) “Wilkes Land Glacial History” Expedition show that approximately 53 million years ago, Antarctica was a warm, sub-tropical environment. During this same period, known as the “greenhouse” or “hothouse” world, atmospheric CO2 levels exceeded those of today by ten times.

Then suddenly, Antarctica’s lush environment transitioned into its modern icy realm. In only 400,000 years — a mere blink of an eye in geologic time — concentrations of atmospheric carbon dioxide decreased. Global temperatures dropped. Ice sheets developed. Antarctica became ice-bound.

How did this change happen so abruptly and how stable can we expect ice sheets to be in the future?

To answer these questions, an international team of scientists participating in the Wilkes Land Glacial History Expedition spent two months aboard the scientific research vessel JOIDES Resolution in early 2010, drilling geological samples from the seafloor near the coast of Antarctica. Despite negotiating icebergs, near gale-force winds, snow, and fog, they managed to recover approximately 2,000 meters (over one mile) of sediment core.

{ ScienceDaily | Continue reading }

photo { Alessandro Zuek Simonetti }

Women who have a smaller waist in relation to their hips tend to be perceived as more attractive. Some argue this is an evolutionary tendency, a desire for women who are perceived to be more fertile, while others suggest it is just a product of the media who, from porn to Prada, laud the image of small waisted women.

The New York Times covers a fascinating study which tested these ideas in an innovative way - by seeing whether blind men, who have avoided the body-shape bias of visual media, would also find women with a lower waist-to-hip ratio more attractive.

{ MindHacks | Continue reading }

photo { via tittaycitay.com | NSFKids }

How long does it take for a litre of water to go through our body?

For normal people it should take about 2 to 3 hours… But it depends on several things.

First, the water has to be absorbed. For example, if someone has really bad diarrhea or is vomiting, the fluid won’t be absorbed.

Second, it depends on what is in the water. If it is pure water rather than water with salt in it, the pure water will be excreted faster than salt water.

Third, if someone is dehydrated, say, was playing soccer for two hours and sweated out two more litres water than he drank, the fluid would stay in his body and his rate of urine production will stay really low until he drinks more.

Fourth, it depends on the time of day. Usually, people’s rate of urine production decreases in the middle of the night and increases around the time we wakes up.

Finally, it depends on the state of health of the person. If a person has kidney disease, the urine production might not increase as much. If a person has heart disease, the fluid May build up in his tissues instead of being excreted.

The reference is a paper where students drank water in the morning and determined how long it took for the water to be excreted. In this paper, it looks like they urinated out about 400 or 500 ml of water over about 2 hours, before the rate of urine production slowed down.

The water runs down the throat, past the epiglottis (which is closed so that water doesn’t end up in the lungs) and down through the oesophagus into the stomach.

In the stomach, water is needed to assist in the processing and digestion of food. So far, the body has not absorbed any water. The only thing that has happened is that any thirst was probably quenched and the amount of saliva has increased.

The water and food are mixed into a dough and kneaded out into the intestines.

In the small intestine, the body starts to absorb fluid, as well as vitamins and other nutrients from the dough. These nutrients are absorbed by the blood and transported to all the body’s cells…

The large intestine’s task is to absorb as much liquid as possible from the thin batter, so that the body can make use of this liquid and achieve a proper balance of body fluids. This is Important, as 60% of the human body is made of water.

The liquid is absorbed by the blood vessels in the large intestine and transported by the blood to the kidneys. In the kidneys, blood is purified and water is converted into urine which flows through the ureters to the bladder. When the bladder contains about 200 - 400ml of urine, signals are usually sent to the brain to promote urination.

{ treebeard31 }

I like the study in that it makes the point very clearly that, yes, there are differences between boys and girls (e.g. girls have ovaries and monthly cycles; boys do not), but, no, mathematical ability is not one of them.

{ Twenty-2-Five | Continue reading }

Humans produce about 50 distinct types of smiles but there’s one distinction that really matters: between real and fake.

If we can tell the people who are showing what they’re feeling from the people who are faking it, then we’ve got a really good indicator of who to trust and work with.

{ PsyBlog | Continue reading }

“Leaves have evolved over millions of years to optimize light collection, transport of nutrients to and from the plant body, and mechanical stability against natural stresses,” says David Young a physicist at the Lawrence Livermore National Laboratories near San Francisco.

The puzzle is how leaves grow into such a wide variety of similar shapes. What process can control this growth? Clearly, there is a genetic component to leaf growth but that cannot be the whole story because leaves on the same plant sometimes grow into different shapes, a phenomenon known as heteroblasty. That’s because environmental factors such as nutrition, sunlight also influence growth and shape.

Various theories attempt to explain leaf shape using ideas such as fractals and the Turing reaction-diffusion process. But none provide a convincing explanation for the variety of leaf shapes that occur in nature.

Today, Young attempts to change that by putting forward a simple model of leaf growth that reproduces much of the spectrum of leaf shapes that appear in nature. (…) In his model, the growth of leaf lobes is governed by the position of leaf veins. The leaf then simply grows in 2 dimensions in a way that is governed by a simple algorithm. It is this growth pattern that determines the ultimate shape of the leaf. In Young’s model, the final leaf shape is really an accidental by product of this growth process.

{ The Physics arXiv Blog | Continue reading }

photo { Ye Rin Mok }

{ 1 | 2 | Unrelated: The strange link between spherium and helium }

A recent study examined the correlation between chocolate consumption and self-reported depression symptoms. (…)

The authors caution that cross-sectional studies have limited ability to explain correlations and are open to spurious findings. They note there findings are compatible with several possibilities:

• Depression drives craving for chocolate as a self-treatment

• Depression drives craving for chocolate for other reasons

• Chocolate may contribute to depressive symptoms

• A physiological factor could drive both depressive symptoms and chocolate consumption

• A more complex undefined relationship could exist

I’d vote for the last option. (…)

To be balanced, it must be noted that other studies found positive health associations with chocolate intake. In an older sample of Finnish men, chocolate preference as a sweet was linked to better overall health, optimism and better psychological well-being.

{ Brain Posts | Continue reading }

{ Our cynicism towards strangers may develop as early as 7 years old. Surprisingly people are even overly cynical about their loved ones, assuming they will behave more selfishly than they really do. | Photo: Tush magazine #3, 2009 }

Imagine two cities, one to the north of where you live and one an equal distance to the south. Should it take longer to drive to the northern city than to the southern one? Of course not. But evidence suggests we subtly believe that going north is more time-intensive than going south.

In this recent study by Leif Nelson and Joseph Simmons in the Journal of Marketing Research, a number of subjects were asked to estimate the travel time for a northbound versus southbound bird. The majority of respondents believed traveling north from the equator would take longer than the reverse. (…)

This striking study reminds us of an essential, if often underappreciated, truth about transportation: Our ideas about where and how to travel, what routes to use and how long they will take, are all prone to subtle distortions that may ultimately shape our decisions about where to go and why. As geographer Colin Ellard notes in his book You Are Here: Why We Can Find Our Way to the Moon, but Get Lost in the Mall, “unlike other animals, which are tightly anchored, body to ground, fixed to the earth with a sureness of footing than can be almost impossible to sunder, human beings seem preternaturally prone to a kind of spatial flight of fancy in which our minds sculpt physical space to suit our needs.”

The north-south imbalance is just one of any number of ways we rearrange objective time and space in our heads. There are the famous examples of geographical distortion, for example, in which people routinely assume that Rome is farther south than Philadelphia or that San Diego is west of Reno (when in both cases the opposite is true). Or take a simple trip into town: Studies have found that people tend to find the inbound trip to be shorter than the outbound trip, while a journey down a street with more intersections will seem to be longer than one with fewer (and not simply because of traffic lights).

Our state of mind on any trip can influence not just our perceptions of time but of geography itself.

{ Slate | Continue reading }

photo { Todd Hido }

A drug used as a general anaesthetic may also work as a remarkably rapid antidepressant, according to a preliminary study.

The drug’s hallucinogenic side effects mean it is unlikely to be prescribed to patients, but it could pave the way to new faster-acting antidepressants, the researchers suggest.

Ketamine is used as an animal tranquiliser, but is perhaps better known as an illicit street drug, sometimes called “special K”. Now researchers have found the drug can relieve depression in some patients within just 2 hours - and continue to do so for a week.

One problem with current antidepressants is that they typically take weeks to kick in. Some studies have found that patients may face a high risk of suicide in the first week after starting an antidepressant treatment because of this lag time. So researchers have been searching for alternative drugs.

{ NewScientist, 2006 | Continue reading }

The question of nutrition is closely related to that of locality and climate. None of us can live anywhere; and he who has great tasks to perform, which demand all his energy, has, in this respect, a very limited choice. The influence of climate upon the bodily functions, affecting their retardation or acceleration, is so great, that a blunder in the choice of locality and climate may not merely alienate a man from his duty, but may withhold it from him altogether, so that he never comes face to face with it. Animal vigor never preponderates in him to the extent that it lets him attain that exuberant freedom in which he may say to himself: I, alone, can do that. (…)

The slightest torpidity of the intestines, once it has become a habit, is quite sufficient to turn a genius into something mediocre, something “German;” the climate of Germany, alone, is more than enough to discourage the strongest and most heroic intestines. Upon the tempo of the body’s functions closely depend the agility or the slowness of the spirit’s feet; indeed spirit itself is only a form of these bodily functions. Enumerate the places in which men of great intellect have been and are still found; where wit, subtlety, and malice are a part, of happiness; where genius is almost necessarily at home: all of them have an unusually dry atmosphere. Paris, Provence, Florence, Jerusalem, Athens–these names prove this: that genius is dependent on dry air, on clear skies–in other words, on rapid organic functions, on the possibility of contenuously securing for one’s self great and even’s quantities of energy. I have a case in mind where a man of significant and independent mentality became a narrow, craven specialist, and a crank, simply because he had no feeling for climate. I myself might have come to the same end, if illness had not forced me to reason, and to reflect upon reason realistically.

Now long practice has taught me to read the effects of climatic and meteorological influences, from self-observation, as though from a very delicate and reliable instrument, so that I can calculate the change in the degree of atmospheric moisture by means of this physiological selfobservation, even on so short a journey as that from Turin to Milan; accordingly I think with horror of the ghastly fact that my whole life, up to the last ten years–the most dangerous years–has always been spent in the wrong places, places that should have been precisely forbidden to me. (…)

But it was ignorance of physiology–that confounded “Idealism”–that was the real curse of my life, the superfluous and stupid element in it; from which nothing good could develop, for which there can be no settlement and no compensation. The consequences of this “Idealism” explain all the blunders, the great aberrations of instinct, and the modest specializations which diverted me from my life-task; as, for instance, the fact that I became a philologist–why not at least a doctor or anything else that might have opened my eyes? During my stay at Basel, my whole intellectual routine, including my daily schedule, was an utterly senseless abuse of extraordinary powers, without any sort of compensation for the strength I spent, without even a thought of its exhaustion and the problem of replacement. I lacked that subtle egoism, the protection that an imperative instinct gives; I regarded all men as my equals, I was disinterested, I forgot my distance from others–in short, I was in a condition for which I can never forgive myself. When I had almost reached the end, simply because I had almost reached it, I began to reflect upon the basic absurdity of my life-ldealism. It was illness that first brought me to reason.

{ Nietzsche, Ecce Homo, 1888 }

photo { Reto Caduff }

Personality impressions associated with four distinct humor styles

This study examined how personality impressions about another person are influenced by the style of humor that person displays. Four distinct styles were examined, with two of these being adaptive (affiliative and self-enhancing humor), and two being maladaptive (aggressive and self-defeating humor). Participants read descriptions of an individual displaying each humor style, and then rated that individual on several other personality attributes (e.g., friendly, complaining). The adaptive humor styles enhanced personality impressions of another individual, whereas the maladaptive styles had strong detrimental effects. Furthermore, participants provided clearly differentiated personality impressions within both the adaptive and maladaptive humor categories. Affiliative humor led to more positive impressions of another than self-enhancing humor; whereas aggressive humor resulted in more negative personality impressions than self-defeating humor. These findings were discussed in terms of approaches to humor that acknowledge the multifaceted nature of this construct and the resulting impact on social relationships.

{ University of Western Ontario, Canada | Scandinavian Journal of Psychology }

… something I’m quite interested in, and it’s related to the Cosmic Microwave Background (CMB). I’ve briefly mentioned the CMB before, but here’s a more decent introduction: when we say CMB we are talking about radiation that was created when the Universe was very very young  - around 300,000 years old. At that time the Universe was hot and radiation (or photons) were the dominant component of the Universe. Because it was so hot at that time, the Universe was actually opaque – matter was ionized, meaning electrons were bobbling about not really being attached to any nuclei because of the high temperature. What this means is that photons could not get very far without bumping into something – they could not travel in a straight line for any decent sort of time, and were perpetually scattered around. That’s essentially what opaque means. However, something special happened around 300,000 years into the Universe’s lifetime, and that was a decrease in temperature that allowed these electrons to settle into atoms, effectively setting the photons free. We call this the time of last-scattering.

{ we are all in the gutter | Continue reading }

For better or for worse, science has long been married to mathematics. Generally it has been for the better. Especially since the days of Galileo and Newton, math has nurtured science. Rigorous mathematical methods have secured science’s fidelity to fact and conferred a timeless reliability to its findings.

During the past century, though, a mutant form of math has deflected science’s heart from the modes of calculation that had long served so faithfully. Science was seduced by statistics, the math rooted in the same principles that guarantee profits for Las Vegas casinos. Supposedly, the proper use of statistics makes relying on scientific results a safe bet. But in practice, widespread misuse of statistical methods makes science more like a crapshoot.

It’s science’s dirtiest secret: The “scientific method” of testing hypotheses by statistical analysis stands on a flimsy foundation. Statistical tests are supposed to guide scientists in judging whether an experimental result reflects some real effect or is merely a random fluke, but the standard methods mix mutually inconsistent philosophies and offer no meaningful basis for making such decisions. Even when performed correctly, statistical tests are widely misunderstood and frequently misinterpreted. As a result, countless conclusions in the scientific literature are erroneous, and tests of medical dangers or treatments are often contradictory and confusing.

{ ScienceNews | Continue reading }

That post was about sleep researcher Jerry Siegel, who argues that sleep evolved as a state of “adaptive inactivity”. According to this idea, animals sleep because otherwise we’d always be active, and constant activity is a waste of energy. Sleeping for a proportion of the time conserves calories, and also keeps us safe from nocturnal predators etc.

Siegel’s theory in what we might call minimalist. That’s in contrast to other hypotheses which claim that sleep serves some kind of vital restorative biological function, or that it’s important for memory formation, or whatever. It’s a hotly debated topic. (…)

Dreams are simply a result of the “awake-like” forebrain - the “higher” perceptual, cognitive and emotional areas - trying to make sense of the input that it’s receiving as a result of waves of activation arising from the brainstem. A dream is the forebrain’s “best guess” at making a meaningful story out of the assortment of sensations (mostly visual) and concepts activated by these periodic waves. There’s no attempt to disguise the shameful parts; the bizarreness of dreams simply reflects the fact that the input is pretty much random. (…)

While Hobson’s theory is minimalist in that it reduces dreams, at any rate in adulthood, to the status of a by-product, it doesn’t leave them uninteresting. Freudian dream re-interpretation is probably ruled out (”That train represents your penis and that cat was your mother”, etc.), but if dreams are our brains processing random noise, then they still provide an insight into how our brains process information. Dreams are our brains working away on their own, with the real world temporarily removed.

{ Neuroskeptic | Continue reading }

Brain injuries caused by strokes, tumors or head trauma can, on occasion, result in Unusual Changes in Sexuality, as discussed in an earlier blog post. A new case report by Bianchi-Demicheli et al. (2010) describes a unique paraphilia in a married 34 year old man. The authors called it Sleeping Beauty paraphilia:

This [man] felt sexually aroused from seeing sleeping women as well as from taking care of their hands and nails while they were asleep.

The patient came to the attention of the authors when he was brought to the emergency psychiatric unit after assaulting his wife with pepper spray while wearing a latex mask.

{ The Neurocritic | Continue reading }

photo { Helmut Newton }

The lure of instant gratification is hard to resist: when we want something, we want it right now. Of course, maturity and reality demand that we learn to wait, that we postpone our pleasures until tomorrow and tomorrow and tomorrow. And so we stash money in our savings account, and forgo the SUV for the sake of climate change and don’t eat the entire pint of ice cream. We resist the tug of immediate delight for the sake of even more delight in the future.

That, at least, is how we’re supposed to behave. The problems arise with a mental process known as delay discounting, which refers to our tendency to discount the value of a future reward as a function of its temporal distance.

{ The Frontal Cortex/ScienceBlogs | Continue reading }

photo { Richard Avedon }

An unprecedented number of tiny, ocean dwelling organisms have been catalogued by researchers involved in a global survey of the world’s oceans.

One of the highlights was the discovery of a vast “microbial mat”, covering an area equivalent to the size of Greece.
Microbes are estimated to constitute up to 90% of all marine biomass.

The findings form part of the Census of Marine Life (CoML), a decade-long project that will present its full results in October.

“In no other realm of ocean life has the magnitude of Census discovery been as extensive as in the world of microbes,” said Mitch Sogin, leader of the International Census of Marine Microbes (ICoMM).

“Scientists are discovering and describing an astonishing new world of marine microbial diversity and abundance.” (…)

The team, involving researchers from the Netherlands and the US, collected samples from more than 1,200 locations, which resulted in the compilation of a dataset containing in excess of 18 million DNA sequences.

CoML researchers suggested that the total number of marine microbes, based on molecular characterisation, could be in the region of one billion species.

They added that the micro-organisms were vital for sustaining life on Earth, as they are responsible for about 95% of respiration in the oceans.

{ BBC | Continue reading | video }

artwork { Roy Lichtenstein, Girl in Water, 1965 }

It’s hard to get good payoffs from slot machines, yes. But it’s also hard to get good information from slot-machine gamblers, and that made things awkward for psychologists Mark Griffiths, of Nottingham Trent University, and Jonathan Parke, of Salford University. They explained how, in a monograph called Slot Machine Gamblers – Why Are They So Hard to Study?

Griffiths and Parke published it a few years ago in the Electronic Journal of Gambling Issues. “We have both spent over 10 years playing in and researching this area,” they wrote, “and we can offer some explanations on why it is so hard to gather reliable and valid data.”

Here are three from their long list.

First, gamblers become engrossed in gambling. “We have observed that many gamblers will often miss meals and even utilise devices (such as catheters) so that they do not have to take toilet breaks. Given these observations, there is sometimes little chance that we as researchers can persuade them to participate in research studies.”

Second, gamblers like their privacy. They “may be dishonest about the extent of their gambling activities to researchers as well as to those close to them. This obviously has implications for the reliability and validity of any data collected.”

Third, gamblers sometimes notice when a person is spying on them.

{ The Guardian | Continue reading }