ScienceDaily: Top Science News

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• Amber discovery indicates Lyme disease is older than human race
• Huge tooth fossil shows marine predator had plenty to chew on
• 'Free choice' in primates altered through brain stimulation
• Four-billion-year-old rocks yield clues about Earth's earliest crust
• Stress degrades sperm quality, study shows
• Outgrowing emotional egocentricity: Linked brain region discovered

Amber discovery indicates Lyme disease is older than human race Posted: 29 May 2014 11:25 AM PDT Lyme disease is a stealthy, often misdiagnosed disease that was only recognized about 40 years ago, but new discoveries of ticks fossilized in amber show that the bacteria which cause it may have been lurking around for 15 million years -- long before any humans walked on Earth. The findings were made by researchers who studied 15-20 million-year-old amber from the Dominican Republic that offer the oldest fossil evidence ever found of Borrelia, a type of spirochete-like bacteria that to this day causes Lyme disease.

Huge tooth fossil shows marine predator had plenty to chew on Posted: 29 May 2014 11:24 AM PDT A fossilized tooth belonging to a fearsome marine predator has been recorded as the largest of its kind found in the UK, following its recent discovery. A team of palaeontologists have verified the tooth, which was found near Chesil Beach in Dorset, as belonging to a prehistoric relative of modern crocodiles known as Dakosaurus maximus. The tooth, which has a broken tip, is approximately 5.5 cm long.

'Free choice' in primates altered through brain stimulation Posted: 29 May 2014 11:24 AM PDT When electrical pulses are applied to the ventral tegmental area of their brain, macaques presented with two images change their preference from one image to the other. The study is the first to confirm a causal link between activity in the ventral tegmental area and choice behavior in primates.

Four-billion-year-old rocks yield clues about Earth's earliest crust Posted: 29 May 2014 08:20 AM PDT It looks like just another rock, but what researchers are examining is a four-billion-year-old chunk of an ancient protocontinent that holds clues about how Earth's first continents formed. Continents today form when one tectonic plate shifts beneath another into Earth's mantle and cause magma to rise to the surface, a process called subduction. It's unclear whether plate tectonics existed 2.5 billion to four billion years ago or if another process was at play.

Stress degrades sperm quality, study shows Posted: 29 May 2014 07:07 AM PDT Psychological stress is harmful to sperm and semen quality, affecting its concentration, appearance, and ability to fertilize an egg, according to a study. It is not fully understood how stress affects semen quality. It may trigger the release of steroid hormones called glucocorticoids, which in turn could blunt levels of testosterone and sperm production. Another possibility is oxidative stress, which has been shown to affect semen quality and fertility.

Outgrowing emotional egocentricity: Linked brain region discovered Posted: 27 May 2014 07:14 AM PDT A region of the brain that enables children to overcome emotional self-centeredness as they mature has been discovered by researchers. Egocentrism refers to the inability to differentiate between one's own point of view and that of other people. Egocentric people consider themselves to be the centre of all activity and assess all events and circumstances from this perspective. They project their own ideas, fears and desires onto the environment and others.

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