Williams syndrome children show no racial stereotypes or social fear | Not Exactly Rocket Science

People with Williams syndrome are some of the friendliest people you’ll ever meet. They are incredibly sociable, almost unnervingly so, and they approach strangers with the openness that most people reserve for close friends.

Their sociable streak is the result of a genetic disorder caused by the loss of around 26 genes. This missing chunk of chromosome leaves people with a distinctive elfin face, a risk of heart problems, and a characteristic lack of social fear. They don’t experience the same worries or concerns that most of us face when meeting new people. And now, Andreia Santos from the University of Heidelberg has suggested that they have an even more unique trait – they seem to lack racial bias.

Typically, children start overtly gravitating towards their own ethnic groups from the tender age of three. Groups of people from all over the globe and all sorts of cultures show these biases. Even autistic children, who can have severe difficulties with social relationships, show signs of racial stereotypes. But Santos says that the Williams syndrome kids are the first group of humans devoid of such racial bias, although, as we’ll see, not everyone agrees.

Santos compared the behaviour of 20 white children with Williams syndrome, aged 7 to 16, and 20 typical white children of similar backgrounds and mental ages. To do so, she used a test called the Preschool Racial Attitude Measure (PRAM-II), which is designed to tease out traces of gender or racial biases in young children.

PRAMII

PRAM-II consists of a picture book where every page includes a pair of people of different genders or skin types. The researcher tells a selection of stories to accompany the images and the children have to point to the person whom they think the story is about. As they hear positive or negative adjectives, they reveal any underlying racial bias if they point to light-skinned or dark-skinned people, or men or women, more frequently.

The typical children showed a strong tendency to view light-skinned people well and dark-skinned people poorly. Out of their responses, 83% were consistent with a pro-white bias. In contrast, the children with Williams syndrome only showed such responses 64% of the time, which wasn’t significantly different from chance.

Williams_syndromeSantos suggests that children with Williams syndrome don’t develop the same biases that their peers do, because they don’t experience social fear. Andreas Meyer-Lindenberg, who led the study, says, “There are hyper-social, very empathetic, very friendly, and do not get danger signals.” And because they’ll freely interact with anyone, they are less likely to cultivate a preference for people of their own ethnic groups. Alternatively, it could be that because they don’t fall prey to stereotypes, they’re more likely to socialise with everyone.

Santos is quick to rule out alternative explanations for this result. Some of the children with Williams syndrome were more intelligent or mentally advanced than the others, but they behaved in the same way. Nor could it be that they suffered from a general inability to assess people’s features, for both groups of children showed a bias towards their own gender.

But not everyone is convinced. Aliya Saperstein from the University of Oregon praised the study’s “clever research design” and said that it shows the Williams Syndrome children are clearly less biased than normal ones. That is interesting in itself, but Saperstein is sceptical that they lack racial bias entirely. In the PRAM-II test, Santos claims that children without any biases should make pro-white responses half of the time, but she showed that the Williams syndrome children did so 64% of the time. This wasn’t significantly different from a chance result but the estimate was based on a very small sample size. Given larger numbers, those extra fourteen percentage points might indicate an important difference.

Robert Livingston from Northwestern University agrees. He says, “I think that it’s problematic to make strong conclusions on the basis of null findings, particularly with a sample as small as 20 WS children.”

It’s also worth noting that the PRAM-II test doesn’t give children the option of a truly unbiased response. They can’t say that the story could fit either image equally – they can only give fewer pro-white answers. As Saperstein says, “The results don’t demonstrate or prove an absence of bias. And like all similar tests, the study may tap partly into one’s knowledge of social stereotypes not just one’s personal biases.”

Livingston also notes that when we’re talking about racial bias, there is a difference between stereotypes, which are based on our beliefs, and prejudices, which are based on our feelings and evaluations of other people. The Williams Syndrome children may not show prejudice, but Livingston says, “Very few if any people who do not show stereotypes.”

Regardless of whether the Williams Syndrome children lack racial bias altogether, it’s clear that they aren’t affected by it to the same extent as normal children. Santos’s results also suggest that racial and gender biases have different origins. The former is borne at least partly out of social fear while the latter has different roots.

The link between social fear and racial stereotypes fits with the results of previous brain-scanning studies. In people with Williams syndrome, the amygdala, a part of the brain involved in processing emotional memories, is far less reactive to threatening social situations. The connections between the amygdala and the fusiform face area, which is specialised for recognising faces, are also unusually weak.

The same areas might play a role in understanding information about people’s race: the fusiform face area tends to be more active when we look at people from the same ethnic group; and one study found that the amygdala is more active when both white and black people look at black faces. This will, of course, need to be tested in more experiments.

Reference: Current Biology; citation unavailable at time of writing

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A Hidden Cosmic Neighbor: Cool Brown Dwarf Found Lurking Near Our Solar System | 80beats

Brown dwarfAstronomers have discovered the closest new star to us that’s been spotted in 63 years. Though “star” might be a stretch, depending upon whom you ask.

The new find, UGPS 0722-05, is less than 10 light years from here. But sky-watchers missed it for so long because it’s a brown dwarf, a member of the murky class of celestial objects that linger between gas giant planets and low-mass stars. Brown dwarfs have so little mass that they never get hot enough to sustain the nuclear fusion reactions that power stars like the sun. Still, they do shine, because they glow from the heat of their formation, then cool and fade [New Scientist]. This dwarf’s temperature is somewhere between 266 and 446 degrees Fahrenheit, making it the coldest scientists have even seen. With its minimal activity, the brown dwarf gives off just 0.000026 percent the amount of light that our sun does.

Like dwarf planets, which cast aside the 9-planet solar system of our childhoods and riled Pluto-philes everywhere, brown dwarfs don’t lend themselves to simple scientific definitions. The International Astronomical Union sets the planet–brown dwarf boundary at 13 times the mass of Jupiter. But that mass limit is an imperfect definition—what of brown dwarf–size bodies that orbit stars, behaving themselves like supersized planets [Scientific American]? The nomenclature could get even messier when the details of this new find are confirmed. Study leader Philip Lucas and his colleagues suggest that the newly discovered brown dwarf is so cool that it might be the first member of a new class of ultralow temperature dwarfs. Although one fingerprint of such a new class, absorption of infrared light by ammonia, appears to be missing, only “time will tell” if the discovery merits a new classification, the researchers note [Science News].

Lucas’ team’s paper is currently being submitted to the journal Nature, where the peer-review process should help to verify how close the team was with its parallax measurement of the brown dwarf’s distance. If they’re correct, UGPS 0722-05 will not only beat out the previous record-holders for proximity to Earth—a binary set of brown dwarfs in the Epsilon Indi system, about 11.8 light-years away—it would also suggest that perhaps more of these shadowy celestial objects linger even closer to us.

Related Content:
DISCOVER: Hi Ho, Hi Ho—Brown dwarfs are the missing links between stars and planets
DISCOVER: Works in Progress—When it’s a planet that’s not a planet
Bad Astronomy: Brown Dwarf T Party
Bad Astronomy: The Upper Limit to a Planet

Image: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)


High RC Capacitors

Dear Engineers,

Can I get a capacitor that will sustain the charges for about 3 to 4 min before its total discharge.

I want the RC = 180seconds

I intend using it an electric motor.

Thousands of it will be needed

Thanks

Lawrence

transformers design

dear all,

kindly advice / guide.

which is better, making the LV side with single layer or double layer of CU foil, keeping the cross section same.

thanks in advance.

SANAD MIGDAD

Three Miles Down in the Carribean, the Deepest Volcanic Vents Ever Seen | 80beats

VentsThe bottom of the sea is a strange and marvelous frontier, as we were reminded last week by the discovery of the first known animals to live without oxygen. Today a team of British researchers say their undersea robotic explorers have found something new down in the depths of the Caribbean Sea: the deepest hydrothermal vents ever seen.

The black smokers, named for how they spew out an iron sulfide compound that’s black, sit 3.1 miles deep in the Cayman Trough in the Caribbean [FoxNews]. They beat out the previous record holders, which were located 2.6 miles below the surface in the middle of the Atlantic Ocean. As the National Oceanography Centre team sailed across the sea in its research vessel, the James Cook, the scientists deployed their robot explorers down to the inhospitable depths. One, called Autosub6000, mapped the seafloor while another, HyBIS, carried high-resolution cameras to capture these images.

Marine biologist Dr Jon Copley said: “Seeing the world’s deepest black-smoker vents looming out of the darkness was awe-inspiring.” He added: “Super-heated water was gushing out of their two-storey-high mineral spires, more than three miles beneath the waves” [BBC News]. The heat record held by the vents in the mid-Atlantic is a scorching 867 degrees Fahrenheit, but Copley and the other researchers say they don’t know yet whether this one is hotter. Geologist Bramley Murton reports mats of microbes covering the vents, but the team is conferring with other scientists before they announce exactly what they found. Whatever lives down there, it’s certainly got grit. The pressure at the bottom of the trough, which is 500 times normal atmospheric pressure, would be the equivalent to the weight of a large family car pushing down on every square inch of the creatures that live there, the researchers say [FoxNews].

You can keep up with the voyage of the James Cook on the team’s Web site. They’ll be cruising the Cayman Trough until the 20th of this month.

Related Content:
DISCOVER: Funky Life at an Underwater Hydrothermal Vent (gallery)
DISCOVER: Water at Ocean Vents Isn’t Water—It’s a Gas-Liquid Hybrid
DISCOVER: For Microbes, Hell Isn’t So Bad
DISCOVER: Sweeping the Ocean Floor
80beats: For This Deep-Sea Animal, Oxygen-Free Is the Way To Be

80beats: NASA’s New Underwater Robot Chugs Along Indefinitely on Ocean Power

Image: National Oceanography Centre


Futurist Ceramic Exhibit Extended

Pubblicità e propaganda. Ceramica e grafica futuriste
Wolfsoniana (Genova-Nervi)
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LA MOSTRA E’ STATA PROROGATA FINO AL 2 MAGGIO

Una mostra sulla produzione ceramica futurista, in occasione del centenario del manifesto di fondazione del movimento futurista.

Accanto al primato albisolese con manufatti degli artisti più noti, quali Diulgheroff, Farfa, Fillia, Munari, Gaudenzi, Aquaviva, la mostra intende indagare anche esperienze artistiche che hanno tangenze linguistiche con il movimento futurista, come la produzione di alcune manifatture italiane, tra cui le Ceramiche Rometti in Umbria, la BMC in Toscana, la FACI in Lazio.

In occasione della mostra, viene inoltre presentata la produzione di argenti del milanese Arrigo Finzi (La Spezia 1890 – Milano 1973) che la figlia Olga Finzi Baldi ha affidato in comodato alla Wolfsoniana.

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Blogging the Kintisch Point of Inquiry Show, Part II: Is It Reasonable to Fear “Playing God”? | The Intersection

Once again: If you haven't yet, I encourage you to download or stream my fourth (and so far, I think, best) Point of Inquiry program--with Eli Kintisch on the subject of geoengineering. All this week on the blog, I'm going to be discussing issues raised on the show--so having heard it will be kind of an essential baseline. I'm always trying to become a better interviewer, so with this next post, I want to zoom in on an area where I failed to press my interview subject as I probably should have. And that is the relationship between religious beliefs and opposition to geoengineering. At around minute 9:15, I asked Eli about religious opposition to geoengineering--basically, about the folks who say that we shouldn't "play God." He gave a very detailed answer, essentially signaling that, hey, yeah, this is a lot like genetically modified foods--some people think the impulse to interfere with "nature," to remake it in the way that only "God" is supposed to do, is wrong. I have no doubt this impulse is out there. But I don't find it to be at all a rational argument, or a sound basis for public policy. When it comes to the genetics of ...


Dramatic glacial retreat caught by NASA satellite | Bad Astronomy

In January through April of 2002, the Larsen B ice shelf collapsed in the Antarctic.

This was a huge sheet of ice, about 3250 square kilometers (1250 square miles) in area, roughly equal to a square 57 km (34 miles) on a side. There had been a series of warm summers that weakened the shelf, and then the very warm summer of 2002 spelled doom for it.

The Landsat 7 satellite took many images of the collapse, but the Earth Observatory Image of the Day just released two dramatic shots of its impact:

craneglacierretreat

The top image was taken on April 6, 2002 — about two months after the shelf collapsed — and the bottom one on February 20, 2003. What you’re seeing is the Crane glacier which flowed out into the ice shelf. See how the end of the glacier has retreated so far back into the bay? The Larsen B ice shelf helped stabilize the glacier, but with the shelf gone, the glacier was free to break off as well. The end result is the glacier edge effectively retreating up the channel. You can see icebergs floating in the bay, some hundreds of meters across.

It’s hard not to wonder about climate change when looking at this. As we reality-based folks are fond of saying, weather (short-term, local environment) is not climate (long-term, larger environment). On the other hand, how many episodes of weather over how large a region does it take to add up to climate?


When a trait isn’t a trait isn’t a traitGene Expression

ResearchBlogging.orgOne of the great things about evolutionary theory is that it is a formal abstraction of specific concrete aspects of reality and dynamics. It allows us to squeeze inferential juice from incomplete prior knowledge of the state of nature. In other words, you can make predictions and models instead of having to observe every last detail of the natural world. But abstractions, models and formalisms often leave out extraneous details. Sometimes those details turn out not to be so extraneous. Charles Darwin’s original theory of evolution had no coherent or plausible mechanism of inheritance. R. A. Fisher and others imported the empirical reality of Mendelism into the logic of evolutionary theory, to produce the framework of 20th century population genetics. Though accepting the genetic inheritance process of Mendelism this is original synthesis was not informed by molecular biology, because it pre-dated molecular biology. After James Watson and Francis Crick uncovered the biophysical basis for Mendelism molecular evolution came to the fore, and neutral theory emerged as a response to the particular patterns of genetic variation which new molecular techniques were uncovering. And yet through this much of R. A. Fisher’s image of an abstract genetic variant floating against a statistical soup of background noise variation persisted, sometimes dismissed as “bean bag genetics”.

We’ve come a long way from the first initial wave of discussions which were prompted by the molecular genetic revolution. We have epigenetics, evo-devo and variation in gene regulation. None of these processes “overthrow” evolutionary biology, though in some ways they may revolutionize aspects of it. Science is over the long haul after all an eternal revolution, as the boundaries of comprehension keep getting pushed outward. A few days ago I pointed to Sean Carroll’s recent work, which emphasizes that one must think beyond the sequence level, and focus on particular features such as cis-regulartory elements. Here we’ve been tunneling down to the level of the gene, but what about the traits, the phenotypes, which are affected by genetic variation?

It is well known that the sparest abstraction of genotypic-phenotypic relationship can be illustrated like so:

genetic variation ? phenetic variation

But each element of this relation has to be examined greater detail. What type of genetic variation? Sequence level variation? Epigenetic variation? The second component is perhaps the most fraught, with the arrow waving away the myriad details and interactions which no doubt lurk between genotype and phenotype. And finally you have the phenotype itself. Are they all created alike in quality so that we can ascribe to them dichotomous values and quantities?

A new paper in PNAS examines the particulars of morphological phenotypes and physiological phenotypes, and their genetic control, as well as rates of evolution. Contrasting genetic paths to morphological and physiological evolution:

The relative importance of protein function change and gene expression change in phenotypic evolution is a contentious, yet central topic in evolutionary biology. Analyzing 5,199 mouse genes with recorded mutant phenotypes, we find that genes exclusively affecting morphological traits when mutated (dubbed “morphogenes”) are grossly enriched with transcriptional regulators, whereas those exclusively affecting physiological traits (dubbed “physiogenes”) are enriched with channels, transporters, receptors, and enzymes. Compared to physiogenes, morphogenes are more likely to be essential and pleiotropic and less likely to be tissue specific. Morphogenes evolve faster in expression profile, but slower in protein sequence and gene gain/loss than physiogenes. Thus, morphological and physiological changes have a differential molecular basis; separating them helps discern the genetic mechanisms of phenotypic evolution.

Morphology here refers to gross anatomical features. The sort of traits and characteristics which a paleontologist or anatomist might take interest in. Physiology is more about function, and the physical structures which enable that function. It is naturally closer to the scale of molecular biology as physiology melts into biochemistry. Of course at the other end physiology also merges with anatomy as physiology occurs within features of interest to the anatomist. By way of generalization perhaps physiology may be considered more granular, while morphology more gross, in the context of this paper.

They used the mouse because it’s a species which has long served as a model organism, and there are a host of well known and characterized mutations for both physiology and morphology. Utilization of mice in these fields in the context of evolutionary research dates back to the early 20th century. So systems biologists have a lot of research that’s already been done to work with. They found 5199 mouse genes with known phenotypes in the Mouse Genome Informatics database. 821 affected only morphological traits and 912 affected only physiological traits.

Figure 1 shows the breakdown by Gene Ontology:

morphfig1

Going by what little I know about these topics the second to the fourth panels aren’t surprising. Morphological traits are built from molecular structures, while the transporter activity classes are a more cellular scale, and so would seem to be below the threshold of salience for morphological traits. The first panel is not something I’d expected, but it makes sense after the fact. Figure 2 clarifies. The right panels have proportions, the left counts.

morphfig1

The primary point is this: morphogenes seem to affect more traits than physiogenes, and, their affect is less tissue specific when it comes to a particular trait. When this pattern is highlighted the enrichment toward transcriptional regulation makes more sense to me it is transcriptional regulation might allows for more trait by trait level control of variation. If there is a relationship of many traits to one gene that would probably impose a constraint on the sequence level to a greater extent than if the gene was implicated in variation on one trait. The gap in pleiotropy is closed somewhat when you constrain to essential genes, those whose mutation results in decrease of fitness to zero (through death or lack of ability to reproduce). Pleiotropy presumably is constraining the genetic landscape toward particular fitness peaks. Tissue specificity seems understandable when you consider the localization of many physiological processes, and their biochemical complexities (I’m thinking of the vagaries of gene expression in the liver here).

But they looked at more than how the traits and genes distribute now, they tried to sniff out if there were differences in the rate of evolution of morphogenes and physiogenes contingent upon the class of genetic variants. Remember that you have sequent level changes on exons which can alter proteins. You have cis-acting elements as critical cogs in gene regulation. And you have more gross genomic features such as gene duplication or deletion.

morphfig3Figure 3 shows the differences between mice and humans on particular genes in relation to sequence level substitutions as well as gene expression profiles. Specifically in the case of the former you want to know the rate of nonsynonymous substitution, those substitutions at base pairs which change the amino acid translated, standardized by the overall mutation rate. So panel C is the one to focus on. Note that physiogenes seem to have evolved more since the last divergence between human and mice lineages than morphogenes. Why might this be? An immediate thought that comes to mind is that tissue-specific expressing physiological processes are liable to be modulated more often than gross morphology, which might be controlled by genes with a lot of pleiotropic effects and so constrained. Even when you control to tissue-specificity the pattern remains, as evident in panel D. The pattern seems somewhat inverted in relation to rate of evolution when it comes to gene expression profiles, as you can see in the last three panels. Evolution happens, but by somewhat different genetic means in these cases. The authors finger pleiotropy in particular as the problem for sequence level evolution in morphogenes, as changes in proteins are much more likely to be problematic if those proteins are upstream from many more traits.

In a way these results show that evolution has to be a versatile designer. When it comes to physiogenes the illustrator is in charge, creating new traits from the most basic genetic raw material, changes in a base pair here and a base pair there. But for morphogenes evolution has to use the tools and tricks of photoshopping, making recourse to extant elements and rearranging or tweaking things here and there so as not to upset the complex applecart while modulating on the margins.

What about cis-acting regulatory elements? In the paper they allude to the argument of Sean Carroll that cis-acting regulatory elements are critical for the evolution of morphological traits. That would imply that morphogenes should be enriched vis-a-vis physiogenes for changes on these elements. They didn’t find that in figure 4. On the contrary.

morphfig4

But I don’t think they perceive their result as a rock-solid refutation of Carroll because it was somewhat indirect. I’ll quote from the paper:

…Because experimentally confirmed mammalian cis elements are few, are likely to have been confirmed in only one species, and are potentially biased toward certain classes of genes,we tested the above hypothesis by using cis-elements that were predicted exclusively by motif sequence conservation among a set of vertebrate genome sequences and recorded in the cisRED database (20). In cisRED, 8,440 predicted mouse cis-elements and 7,688 predicted human cis-elements were found to be in the proximity of 586 mouse morphogenes and their human orthologs, respectively. Similarly, 7,082 mouse cis-elements and 7,215 human cis-elements were predicted for 621 physiogenes….

I’m inclined to accept this result and its generalizability, but there’s a layer of analysis and modeling in this case which doesn’t exist in the others. Additionally, Carroll’s thesis is about the whole animal kingdom and a mouse-human comparison may be atypical.

Finally they wanted to look at gene duplication. They found:

Together with the Dfam result, our analyses show that, whereas physiogene families expand/contract faster than morphogene families, the rate of expansion/contraction is relatively constant across lineages for a given family.

I wonder if the duplication here might have something to do with modulating dosages of various substrates in biochemical processes. This may have more direct relevance to physiological processes.

It is important to note as they did that the category “morphogene” and “physiogene” is somewhat artificial, as is the distinction between morphology and physiology. Nature is fundamentally one, and we break it apart as particular joints for ease of our own abstractions and categorizations. Additionally all genes presumably have some effect on morphology and physiology, and though this exploration looks under the hood a bit more than some of the older abstractions it too is a simplification. The key is that the argument here seems to be that these breaking apart of categories and processes gives us useful marginal return in comprehension of evolutionary dynamics. A trait is not always just a trait. Different classes of phenotypes may have different evolutionary genetic implications by their very nature. Some of this is common sense, those traits which are less functionally significant will exhibit more genic variation. But distinctions in terms of form and function themselves are at a further level of detail. And, I presume that generalizations that we make from mouse-human comparisons as here have some limitations across the tree of life.

Citation: Liao BY, Weng MP, & Zhang J (2010). Contrasting genetic paths to morphological and physiological evolution. Proceedings of the National Academy of Sciences of the United States of America PMID: 20368429

Queries on Drive Shaft

I have a slip and yoke drive_shaft. It is driven by a PTO and drives a pump. I am trying to calculate the minimum outside diameter of the shaft. Is there a formula for that? Does the slip length matter as well?

Caterpillars must walk before they can anally scrape | Not Exactly Rocket Science

The masked birch caterpillar creates its own home by weaving leaves together with silk. Once built, it vigorously defends its territory but, like many animals, it prefers to intimidate its rivals before resorting to blows. To display its strength and claim its territory, it drums and scrapes its jaws against the leaf. It also drags its anus across the surface to create a complex scratching noise. This “anal scraping” message seems utterly bizarre, but its origins lie in a far more familiar activity – walking.

Warding a rival off with your anus might seem unseemly to us, but caterpillars that do this turn out to be rather civilised species. The scraping is based on the same walking movements that their ancestors used to chase after rivals. The other parts of their signalling repertoire – drumming and scraping jaws – are ritualised versions of fighting moves like biting, butting and hitting. While their earlier cousins might resort to such fisticuffs, the anal-scrapers conduct their rivalries with all the restraint of Victorian gentlemen.

These signals and their evolution have been decoded by Jaclyn Scott from Carleton University. They a great examples of how ritualised animal communiqués evolve from much simpler actions that have little if anything to do with communication – walking, breathing, hunting and the like. Crickets, for example, sing by rubbing their wings together, which may originally have been done to release pheromones or to prep the wings for flight. The whistling of wind through the feathers of crested pigeons has turned into an alarm. The competitive knee-clicks of eland antelopes are made by tendons that slide as a natural part of their gait.

Often, these origins are hard to test and scientists need to be careful if they aren’t to rely on fanciful just-so stories. To avoid that, Scott analysed 36 species of caterpillars from two different families. Some of them had simple struts called “pro-legs” on their end segment, which they use to inch their way along. Other species lacked these structures and in their place, they had a pair of “anal oars” – thicker, harder, spatula-shaped versions of the caterpillar’s normal hairs. These are the instruments that the larvae use to scrape their leaves.

These two groups of caterpillars put their bums to different uses – walking and talking – but the movements they make are the same. They lift the anal segment forward, place it on the leaf and their push backwards against it. The big difference is that in the walkers, the end stays put and the front half launches forward, while in the talkers, the front stays attached and the bum moves backwards. When the masked birch caterpillar makes its anal scrapes, it is essentially talking by walking on the spot.

Caterpillars

To confirm this analogy, Scott sequenced DNA from her three dozen species and built a family tree that charted their evolutionary relationships. She found that the species with the pro-legs – the walkers – came first. They solve their conflicts with violence, crawling towards intruders and physically attacking them.

Those with anal oars – the talkers – are an offshoot that descended from this larger group and lost their anal pro-legs. In this group, all the aggressive movements on their cousins have become ritualised into signals. Instead of a confrontational crawl, they do an anal scrape. Instead of biting, hitting and butting, they scratch and drum the leaves with their jaws instead.

Scott also found that the original movements already had the foundations of a good signal. The crawling and pushing movements of a defensive caterpillar produce vibrations that you can pick up over background noise. As these movements became ritualised into signals, they became simpler too, so that caterpillars that send messages by anal scraping produce much larger and more repetitive vibrations using fewer body movements. This is exactly what you’d expect to happen over time – as messy but informative behaviour evolves for use in communication, it becomes clearer and less ambiguous.

Reference: Nature Communications http://dx.doi.org/10.1038/ncomms1002

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Solar Aussie

I have 40 1.8 metre solar evacuated tubes for hot water and at present 12 ,300 watt sunpower panels onto a 3.8 sunnyboy inverter straight to grid, I am soon to have 14 panels as temperature losses keep normal output below 3kwh.

I have read peoples thoughts about cooling and I tried just sim