Scientists have confirmed the second-ever case of a 'virgin birth' in a shark, further confirming that female sharks can reproduce without mating and that many female sharks may have this incredible capacity.

Lead author Dr. Demian Chapman, shark scientist with the Institute for Ocean Conservation Science at Stony Brook University, Beth Firchau of the Virginia Aquarium & Marine Science Center, and Dr. Mahmood Shivji, Director of the Guy Harvey Research Institute and Professor at Nova Southeastern University in Florida, have proven through DNA testing that the offspring of a female blacktip shark named 'Tidbit' contained no genetic material from a father.

The stickleback fish, Gasterosteus aculeatus, is one of the most thoroughly studied organisms in the wild, and has been a particularly useful model for understanding variation in physiology, behavior, life history and morphology caused by different ecological situations in the wild.

On biological levels from molecular and genetic to developmental and morphological, and finally ending with the population level, it has proven far more complex than even imagined.

Studies of stickleback have provided us with a much better understanding of how organisms cope with new environmental conditions, first through acclimation over an individual's lifespan, and subsequently through adaptation of population via changes in gene form (allele) frequencies.

Given the rapidly changing global environment, this research not only provides insight into evolutionary processes, but is of practical importance in understanding how organisms will adapt to a changing world.

In a seminar co-organized by Stanford University and the American Institute of Mathematics, Kannam Soundararajan, Professor of Mathematics, announced that he and Roman Holowinsky have proven a significant version of the quantum unique ergodicity (QUE) conjecture.

The motivation behind the problem is to understand how waves are influenced by the geometry of their enclosure. Imagine sound waves in a concert hall. In a well-designed concert hall you can hear every note from every seat. The sound waves spread out uniformly and evenly. At the opposite extreme are "whispering galleries" where sound concentrates in a small area.

The mathematical world is populated by all kinds of shapes, some of which are easy to picture, like spheres and donuts, and others which are constructed from abstract mathematics. All of these shapes have waves associated with them. Soundararajan and Holowinsky showed that for certain shapes that come from number theory, the waves always spread out evenly. For these shapes there are no "whispering galleries."

This week, Astronomy & Astrophysics is publishing new observations with AMBER/VLTI of the gas component in the vicinity of young stars. An international team of astronomers led by E. Tatulli (Grenoble, France) and S. Kraus (Bonn, Germany) [1] used the VLT near-infrared interferometer, coupled with spectroscopy, to probe the gaseous environment of Herbig Ae/Be stars. These are young stars of intermediate mass (approximately 2 to 10 solar masses), which are still contracting and often show strong line emissions.

Scientists from the Universities of Bath and Exeter have developed a rapid new way of checking for toxic genes in disease-causing bacteria which infect insects and humans. Their findings could in the future lead to new vaccines and anti-bacterial drugs.

They studied a bacterium called Photorhabdus asymbiotica, which normally infects and kills insects, but which can also cause an unpleasant infection in humans.

By testing groups of genes from the bacteria against three types of invertebrates (insects, worms and amoebae) and mammalian cells, the scientists were able to identify toxins and other molecules, called virulence factors, made by the bacteria that allow it to infect each type of organism.

Sleep in man is divided in two main phases : non-REM sleep, which occupies most of our early sleep night, and REM sleep, during which our dreams prevail. Non-REM sleep is usually considered as a compensatory ‘resting’ state for the brain, following the intense waking brain activity. Indeed, previous brain imaging studies showed that the brain was less active during periods of non-REM sleep as compared to periods of wakefulness.

Although not rejecting this concept, researchers from the Cyclotron Research Centre of the University of Liège in Belgium and from the Department of Neurology of Liege University Hospital demonstrate that, even during its deepest stages (also called ‘slow-wave-sleep’), non-REM sleep should not be viewed as a stage of constant and continuous brain activity decrease, but is also characterized by transient and recurrent activity increases in specific brain areas.