My picks from ScienceDaily

Why Some Bird Species Lay Only One Egg:

Why do some species of birds lay only one egg in their nest, while others lay 10 or more? A global study of the wide variation among birds in this trait, known as the "clutch size," now provides biologists with some answers. The study, published in the current issue of the journal PLoS Biology, combined data on the clutch sizes of 5,290 species of birds with information on the biology and environment of each of these species.

Secret Ingredient For The Health Of Tropical Rainforests Discovered:

A team of researchers led by Princeton University scientists has found for the first time that tropical rainforests, a vital part of the Earth's ecosystem, rely on the rare trace element molybdenum to capture the nitrogen fertilizer needed to support their wildly productive growth. Most of the nitrogen that supports the rapid, lush growth of rainforests comes from tiny bacteria that can turn nitrogen in the air into fertilizer in the soil.

Dogs Feel Envy, Austrian Study Finds:

Dogs can feel a simple form of envy, researchers have found. Experiments with various species have shown that monkeys often express resentful behavior when a partner receives a greater reward for performing an identical task. Monkeys have been shown to stage strikes, refusing to participate and ignoring what they perceive as inferior compensation. Dogs are capable of similar, though less sensitive, discrimination, report Friederike Range and colleagues.

Dinosaurs Were Airheads, CT Scans Reveal:

Paleontologists have long known that dinosaurs had tiny brains, but they had no idea the beasts were such airheads. A new study by Ohio University researchers Lawrence Witmer and Ryan Ridgely found that dinosaurs had more air cavities in their heads than expected. By using CT scans, the scientists were able to develop 3-D images of the dinosaur skulls that show a clearer picture of the physiology of the airways.

Higher Rates Of Mental Illness Among The Homeless In Western Countries:

Homeless people in Western countries have substantially higher rates of mental health problems than the general population, according to results from a systematic review and meta-analysis published in PLoS Medicine. Searching for studies over the past four decades containing data on the prevalence of mental disorders in homeless people, Seena Fazel and colleagues of the University of Oxford identified 29 studies involving 5,684 homeless individuals based in the US, UK, mainland Europe, and Australia. Combining the data from the surveys, the researchers found that the prevalence of serious mental disorders was raised compared with expected rates in the general population.

Why Do People Make 'A Mountain Out of a Molehill?' Aggression, Status And Sex:

Have you ever wondered why it seems like the littlest things make people angry? Why a glance at the wrong person or a spilled glass of water can lead to a fist fight or worse? University of Minnesota researcher Vladas Griskevicius has three words to explain why people may be evolutionarily inclined to make a mountain out of molehill: aggression, status and sex.

When 2 + 2 = Major Anxiety: Math Performance In Stressful Situations:

Imagine you are sitting in the back of a classroom, daydreaming about the weekend. Then, out of nowhere, the teacher calls upon you to come to the front the room and solve a math problem. In front of everyone. If just reading this scenario has given you sweaty palms and an increased heart rate, you are not alone.

100-meter Sprint World Record Could Go As Low As 9.48 Seconds:

2008 was a great summer for sports' fans. World records tumbled at the Beijing Olympics. Usain Bolt shattered both the 100m and 200m world records, knocking tenths of a second off each. People have been getting faster and faster over the last few decades, which made marathon runner Mark Denny, from Stanford University, wonder whether last century's massive increase in population could account for these dramatic improvements. He also wondered whether there are absolute limits on running speeds and, if so, how close are we to them? Suspecting that there are, Denny decided to scrutinise the running performances of humans and two other famous racing species, dogs and thoroughbred horses, to find how close modern runners are to their species' peak performances.

Semantic Desktop Paves Way For Semantic Web:

European researchers have developed innovative software to make finding information on your computer and sharing it with others considerably easier. In the process, they may have solved the chicken and egg problem that has held back development of the semantic web. Annotating information with semantic data so that its meaning is understood by machines as well as humans has been heralded as the next evolution of the internet - giving more meaningful structure to the jumbled and disjointed results of web searches. However, the vision of the semantic web has largely failed to materialise because there is little incentive to create semantic content when there are few services that use it. And there are few services that use it because there is so little semantic content.

Tropics No Longer Museum Of Plant Biodiversity:

Researchers at the University of Calgary have found the biodiversity picture in the region known as the "lungs of the Earth" contradicts commonly held views relating to extinction in that area. A paper published in PLoS One by Jana Vamosi and Steven Vamosi outlines that the risk of extinction for plants is higher in countries close to the equator than previously thought.

Time Running Out On Coral Reefs As Climate Change Becomes Increasing Threat:

Increasing pressures from climate change will reach a tipping point in less than a decade triggering a significant decline in the health of the planet's coral reef ecosystems according to the findings in an international report.

Why Do Pigs Die During Commercial Transportation?:

An international team of scientists, led by Spain's Luis Fernando Gosálvez, has carried out a study in five European countries to identify and evaluate the factors involved in causing injuries or even death in pigs as they are transported to abattoirs. The results show that the stress and suffering the animals undergo would be reduced if more time was spent on loading them properly onto trucks and the temperature was kept down.