30
May
2007

Animal intelligence0

30-May-2007 Spiders, mice and squids have different personalities just as humans do. Personality differences have been seen in more than 60 species, including primates, rodents, birds, fish, insects and molluscs,

But the evolutionary origins of animal personality – consistent behavior over time and in different situations – is a mystery. Why do different personalities exist in a single population? Shouldn’t one type be more successful than any other?

In a simple, static world maybe. But not in the complex, constantly changing environment of the real world. New research from the Santa Fe Institute is beginning to offer an explanation for the evolution of animal personalities.

These are often shaped by a simple underlying principle, the researchers note: The more an individual stands to lose in terms of future reproduction, the more cautiously it behaves.

Personality differences are often about willingness to take risks, they point out. And individuals often have to make trade-offs between current and future reproduction. The more they invest in reproduction now, the less resources are left for future opportunities, and vice versa.

Using a mathematical model the authors demonstrate that this trade-off can create a variety of personalities in a population. Individuals who invest more in future reproductive success evolve to avoid taking chances. Those that emphasise current reproductive success evolve risk-taking personalities.

So now you know what the scary-looking spider that scurries away as soon as it sees you has on its little arachnid mind.

1-March-2007 South Africa’s environment minister has offered a new plan to control the nation’s booming elephant population by mass killing.

30-Oct-2006 Elephant consciousness story and science teaching resources (US or UK English) posted at www.realscience.org.uk

29
May
2007

Exotic astronomy0

28-May-2007 Astronomers

Astronomers have been probing the properties of one of the most extreme binary star systems ever seen. Located in the Large Magellanic Cloud, LH54-425 consists of two O-stars, the most massive and luminous types of star in the Universe.

These giants are spinning around each other in just 2.25 days. They are so close together that they are almost certain to coalesce to form a huge, hot monster of a star.

“These stars are evolving in the blink of an eye compared to the sun, which has looked pretty much the same for over 4 billion years,” says Rosina Iping, leader of the team that made the observations using NASA’s Far Ultraviolet Spectroscopic Explorer satellite.

8
May
2007

Smart materials0

3-May-2007 A new computer model shows that objects can be made invisible at close range.

At present invisibility cloaks made of metamaterials only work with microwaves and when viewed from afar. They are likely to be used first in military technology, says the University of Liverpool’s Sébastien Guenneau: “The shape and structure of aeroplanes make them ideal objects for cloaking, as they have a fixed structure and movement pattern.

“Human beings and animals are more difficult, as their movement is very flexible, so the cloak – as it is designed at the moment – would easily be seen when the person or animal made any sudden movement.

“A cloak such as the one worn by Harry Potter is not yet possible, but it is a good example of what we are trying to move towards.”

2-May-2007 Scientists and fashion designers come together to create a garment that can prevent colds and flu and never needs washing, and another that destroys harmful gases and protects the wearer from smog and air pollution.

The two-toned gold dress and metalled denim jacket contain cotton fabrics coated with nanoparticles. They look cool and protect the wearer, and at $10,000 a square yard they’re what every well-dressed millionaire could be soon wearing.

25-Apr-2007 New Scientist reports that a Spiderman outfit, complete with gloves and boots to stick to walls, and a silk spinner to swing between buildings, may be just 10 years away. Geckos can hang upside down by one toe because their feet have millions of tiny elastic hairs called setae. Spiders dangle on silk that’s fine but incredibly strong. Throw in nanotube technology to mimic these natural examples at the molecular level and you’re well on the way to your first superhero suit.

18-Apr-2007 Imagine a material that can make light from electricity or electricity from light. It’s a window in daytime, a lighted wall in the evening. It’s clothes that display changing messages, or alter colour at the touch of a button. It’s a mobile, flexible source of solar power. Organic light emitting devices can be all these things and more. An international research group has just been set up to explore the fundamental science and bring potential applications closer to market.

10-Apr-2007 Scientists are constantly coming up with ways to repair the human body, replacing defective and worn-out parts with plastic, titanium, or ceramic substitutes. But the body often rejects these. Now researchers at Brown and Purdue universities have found that changing the surface texture of implants can dramatically improve their acceptance by the body’s defences.

5-Apr-2007 Stronger than steel and more elastic than rubber, spider silk is unsurpassed in its expandability, resistance to tearing, and toughness. It would be an ideal material for a large variety of medical and technical applications. A team at University of Munich has now used genetic engineering to produce one of the spider silk proteins of the European garden spider.

2-Apr-2007 Researchers at Purdue University take a first step toward creating an invisibility cloak that operates in the visible range. A major limitation is that it only works at one frequency.

28-March-2007 Scientists at the University of Illinois make the world’s smallest chain-mail fabric.


20-Oct-2006 Invisibility cloak story and science teaching resources (US or UK English) posted at www.realscience.org.uk

7
May
2007

Babies’ brains0

7-May-2007 The time of year a baby is conceived can affect his or her future achievement, say researchers at Indiana University School of Medicine.

Dr. Paul Winchester and colleagues found lower school test scores in children conceived in June through August. “The fetal brain begins developing soon after conception,” he said. “The pesticides we use to control pests in fields and our homes, and the nitrates we use to fertilize crops and even our lawns, are at their highest level in the summer.”

7-Nov-2006 Chemical pollution may have damaged the brains of millions of children worldwide, say researchers from the Harvard School of Public Health and the Mount Sinai School of Medicine. Story and science teaching resources (US or UK English) posted at www.realscience.org.uk

7
May
2007

Exoplanets0

7-May-2007 As the first space mission dedicated entirely to the search for extra-solar planets, COROT has provided its first image of a giant planet orbiting another star. The unexpected accuracy of the data shows that COROT will be able to see rocky planets maybe even as small as Earth, and possibly provide an indication of their chemical composition.

19-Apr-2007 Giovanna Tinetti is an expert on detecting signs of life across interstellar space. We caught up with her as she made an exploratory visit to the city that will be her home for the next three years.

3-Apr-2007 A Neptune-class planet has been discovered around the nearby red dwarf GJ 674. “We’re not down to Earth-mass planets yet, but this is an interesting find,” says Paul Gilster at Centauri Dreams.

9-Jan-2006 Supersonic winds, maybe as strong as 9,000 miles an hour, are churning the atmospheres of distant planets. Comment and discussion Story and science teaching resources (US or UK English) posted at www.realscience.org.uk

1
May
2007

Climate change0

30-Apr-2007 Traffic restriction over a 3-day period in Beijing managed to reduce emissions of one class of polluting gases by a whopping 40%, say researchers. “I don’t think a proper analysis has ever been made before of such a remarkable shift of environmental policy in such a short period of time,” says Harvard’s Michael McElroy. “I think the real value here is that these kinds of restrictions can really bring about significant change.”

28-Apr-2007 Researchers disprove a recent study suggesting that plants emit the potent greenhouse gas methane. Using a photo-acoustic laser technique, the team of Dutch scientists found that methane emissions from plants are negligible, and do not contribute to global climate change.

The methods were so highly sensitive that the scientists could measure the carbon dioxide in the breath of ants.

Questions remain and the gap in the global methane budget does need to be properly addressed, say the researchers. But there is no reason to “reassess the mitigation potential of plants”.

26-Apr-2007 Strange things happen in the twilight zone. Carbon dioxide absorbed by photosynthesizing marine plants near the sunlit ocean surface does not all sink to the depths.

Instead the carbon on sinking marine particles is often consumed by animals and bacteria, and recycled in the twilight zone—100 to 1,000 meters below the surface—so it never reaches the deep ocean.

Using new technology, a multi-national team has discovered that the twilight zone acts as a gate, allowing more sinking particles through in some regions and fewer in others. This makes it more difficult for the moment to predict the ocean’s role in offsetting the impacts of greenhouse gases.

17-Apr-2007 Climate change could trigger boom and bust population cycles that make animal species more likely to go extinct. Conditions that produce plenty of food and result in a population boom set the stage for a later population crash.

3-Apr-2007 The maximum extent of Arctic sea ice in winter 2007 was the second lowest on satellite record, narrowly missing the 2006 record, according to a team of University of Colorado at Boulder researchers.

11-Dec-2006 The Arctic Ocean could become nearly free of ice in summer by 2040, according to calculations on the impact of greenhouse gas emissions. Simulations on supercomputer show that the ice could disappear very suddenly. Story and science teaching resources (US or UK English) posted at www.realscience.org.uk

29
April
2007

Scent science0

29-Apr-2007 The only nerve cells in the body to run directly from the brain to the outside world, olfactory cells – which give us our sense of smell – are in constant danger of being killed by harsh chemicals in the air.

Researchers have now identified a backup supply of stem cells that can repair the most severe damage to these nerves. These reservists normally lie around doing nothing, but jump into action when smell cells die.

“These stem cells act like the Army Reserves of our nose, supporting a class of active-duty stem cells that help repair normal wear and tear,” explains lead author Randall Reed. “They don’t come in until things are really bad.”

19-Apr-2007 For the first time scientists predict the effect of small changes in a molecule on its scent. The results prove that it is “the electronic surface structure of a molecule” that defines its fragrance, say the researchers.

26-Dec-2006 Exposure to scents helps the brain to distinguish other similar scents. Researchers presented a single odour to human subjects for a few minutes. Half got a minty odour, the other half a flowery one. This brief sensory exposure created mint or floral expertise, respectively, at least for a time. Story and science teaching resources (US or UK English) posted at www.realscience.org.uk

27
April
2007

Ocean ecosystems0

26-Apr-2007 Strange things happen in the twilight zone. Carbon dioxide absorbed by photosynthesizing marine plants near the sunlit ocean surface does not all sink to the depths.

Instead the carbon on sinking marine particles is often consumed by animals and bacteria, and recycled in the twilight zone—100 to 1,000 meters below the surface—so it never reaches the deep ocean.

Using new technology, a multi-national team has discovered that the twilight zone acts as a gate, allowing more sinking particles through in some regions and fewer in others. This makes it more difficult for the moment to predict the ocean’s role in offsetting the impacts of greenhouse gases.

3-Apr-2007 Coral reefs around the world are being exploited unsustainably. To support current levels of fishing an additional area almost four times that of Australia’s Great Barrier Reef would be needed. These figures will nearly triple by 2050.

2-Nov-2006 Research shows that all stocks of fish and seafood in the oceans will collapse within forty years. Story and science teaching resources (US or UK English) posted at www.realscience.org.uk

26
April
2007

News from the isotopes0

23-Apr-2007 One of the weirdest organisms that ever lived, Prototaxites had tree-like trunks that stood more than 20 feet high, making it the largest known land organism of its time – 420 to 350 million years ago. It has been classed as a conifer, a lichen and various types of algae. But carbon isotope analysis of the fossil and the plants that lived in the same environment has shown that Prototaxites “displayed a much wider variation in its ratio of carbon-12 to carbon-13 content than would be expected in any plant.”

This supports the idea that the beast was actually a “humongous fungus“, says Carol Hotton of the National Museum of Natural History.

This is an application of the same technology, derived from the difference between C3 and C4 photosynthesis, as the previous story

9-Jan-2007 Paranthropus is an ancestor of modern humans who has often been seen a a specialist who lacked a varied diet. That is why Paranthropus went extinct, it was thought, as the climate changed and Africa became drier, while tool-wielding Homo, with a highly varied diet, survived. But a new study, using carbon isotope analysis of four fossil teeth, shows that Paranthropus also ate a variety of foods and the explanation for extinction must go deeper. Story and science teaching resources (US or UK English) posted at www.realscience.org.uk

26
April
2007

Science background0

How photosynthesis tells us what our ancestors ate

1 We can learn an incredible amount about the nature and behaviour of plant, animal and even human life in the distant past by studying the ratio of carbon-13 to carbon-12 in their fossils. It works like this (explanation originally written for older kids):

2 One of the most important gases in the atmosphere is carbon dioxide.
3 Green plants absorb carbon dioxide from the atmosphere and release oxygen.
4 This is called photosynthesis.
5 It is the source of all food on Earth and of the oxygen we breathe.
6 The carbon in carbon dioxide occurs in two slightly different forms: carbon-12 and carbon-13.
7 These are called isotopes of carbon.
8 The carbon-13 isotope makes up 1% of the carbon in the atmosphere.
9 The other 99% of carbon in the atmosphere is carbon-12.
10 So you might expect the carbon in plants and trees to have these same proportions.
11 But photosynthesis is a complex and inefficient process.
12 It slightly prefers the lighter carbon-12.
13 So the carbon trapped in plants and trees has a greater fraction of carbon-12 than the atmosphere.
14 And a lower fraction of carbon-13
15 Now it gets slightly more complicated:
16 Normal photosynthesis is even more inefficient in hot, dry conditions.
17 So a slightly different form of photosynthesis appeared in some tropical plants around 65 million years ago.
18 Tropical grasses, sugar-cane and maize (often called corn) use this newer method of photosynthesis.
19 These are called C4 plants.
20 The vast majority of green plants and trees continue to use the old method.
21 These are called C3 plants.
22 C4 plants prefer carbon-12 to carbon-13, just as C3 plants do.
23 But they don’t prefer it quite as strongly.
24 So C4 plants end up with a slightly greater fraction of carbon-13 than C3 plants.
25 This means that the carbon trapped in tropical grass (a C4 plant) on the savannah, has a greater fraction of carbon-13 than does the carbon trapped in the forest trees (C3 plants).
26 The last steps come from noticing that the carbon in plants that are eaten goes to build bodies.
27 So the carbon isotope proportions of hair, nails, teeth and bones reflect the carbon isotope proportions of the plants that have been eaten.
28 They still reflect those fractions after the animal or human are long dead.
29 So a scientist sitting in a lab in Utah can tell what an early human was eating by studying pieces of his 2 million-year-old tooth.
30 The scientist can even tell what the early human was eating at different times of the year by studying different parts of the tooth.
31 Notice that whether the early human was eating tropical grass or animals grazing on that grass, the carbon isotope proportions will show that he or she had a C4 diet.
32 Note: This whole method works because both carbon-12 and carbon-13 are stable isotopes.
33 This means they are not radioactive and so don’t change as time passes.
34 Carbon-14, which is used in carbon dating, is not stable – it is radioactive and does change with time.
35 But neither carbon-14 nor radiocarbon dating has anything to do with the science of this story.