Sabre-toothed cat's teeth grew twice as fast as modern lions'

The fossilised jaw of an adult Smilodon fatalis shows the fully erupted canine. [Credit: © AMNH/J. Tseng]

The terrifying, dagger-like teeth of the sabre-toothed cat Smilodon fatal is grew at twice the rate of those of modern big cats, a new study has found.

However, the teeth in the prehistoric species emerged later in life and even despite their relatively fast growth-rate, the canine teeth were not fully developed until the cat was three years old.

The findings, published today in the journal PLOS ONE, are based on a new technique that combines isotopic analysis and x-ray imaging. It provides for the first time specific ages for developmental events in Smilodon, notably in their teeth.

The study estimates that the eruption rate of permanent upper canines was six millimeters a month – double the growth rate of an African lion's teeth. 

"For predators such as big cats, an important determinant of an individual's full hunting ability is the time required to grow their weapons – their teeth," said Z. Jack Tseng, a National Science Foundation and Frick Postdoctoral Fellow in the American Museum of Natural History's Division of Paleontology and a coauthor on the new paper.

"This is especially crucial for understanding sabre-toothed predators such as Smilodon."

S. fatalis lived in North and South America until going extinct about 10,000 years ago. About the size of a modern tiger or lion but more solidly built, the cats are famous for their protruding canines, which could grow to be 18 centimeters (about 7 inches) long. Although well-preserved fossils of S. fatalis are available to researchers, very little is known about the absolute ages at which the animals reached key developmental stages.

Wolf volcano erupts in the Galapagos

Credit: NASA Earth Observatory image by Jesse Allen.

Credit: NASA Earth Observatory image by Jesse Allen.

The highest volcano in the Galapagos Islands erupted in May for the first time in 33 years. Wolf Volcano on Isabela Island sent smoke and ash about 15 kilometres into the sky, while lava flowed down its southern and eastern slopes into the sea. The lava appeared to subside in early June.

The above image of Wolf was taken in June by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on the Terra satellite. It is a false colour image with vegetated areas appearing as red and lava generally showing as charcoal or black. 

Wolf rises 1,710 metres above sea level. The volcano's seven-kilometre caldera is nearly 700 metres deep.

 

Inaugural Asteroid Day kicks off with a petition

An artist's conception of an asteroid smashing into a proto-planet. The image is based on data collected by NASA's Spitzer's Space Telescope about an explosion near star NGC 2547-1D8 in August 2012-2013. The collision took place in the zone around the star where rocky planets are likely to form.

An artist's conception of an asteroid smashing into a proto-planet. The image is based on data collected by NASA's Spitzer's Space Telescope about an explosion near star NGC 2547-1D8 in August 2012-2013. The collision took place in the zone around the star where rocky planets are likely to form.

A petition calling for more resources to track potentially deadly asteroids was signed by eminent scientists, artists and musicians to mark the first Asteroid Day (June 30).

The petition calls for "a rapid 100-fold acceleration of the discovery and tracking of near-Earth asteroids to 100,000 per year within the next 10 years".

It says that of the million asteroids in our Solar System that have the potential to destroy a city only 10,000 (or 1%) have been identified. Asteroid Day was launched last year by Queen guitarist and astrophysicist Brian May and filmmaker Grigorii Richters.

The day marks the anniversary of the largest asteroid strike in recent times, the Tunguska event in Siberia, 1908, when 2,000 square klometres of conifer forest was flattened by a 40-metre rock that exploded in the atmosphere. 

Eminent signatories of the petition include Peter Gabriel, Richard Dawkins, Brian Cox and Eileen Collins, the first female commander of NASA's space shuttle.

 

Alan Trounson honoured for stem cell research

Alan Trounson, winner of the International Society for Stem Cell Research public service award.

Alan Trounson, winner of the International Society for Stem Cell Research public service award.

Alan Trounson has been awarded the International Society for Stem Cell Research public service award. 

Trounson was honoured for his work in promoting stem cell research internationally. He is known as a pioneer of in-vitro fertilisation (IVF) and was an early stem-cell researcher and advocate for the therapeutic use of human embryonic stem cells.

Trounson was the founder of the Australian Stem Cell Cente and president of the California Institute of Regenerative Medicine. In these roles he developed programs with strong public outreach components to encourage dialogue between researchers and their communities.

The award was given to Trounson at the ISSCR's annual meeting in Stockholm, Sweden on the weekend.

 

.

 

Can too much vitamin B cause acne?

143276841

Too much vitamin B12 may cause acne, or at least make it worse, according to a new study in the US.

"I think there's a link" between vitamin B12 and acne, Huiying Li, of UCLA, a co-author of the study, told Live Science.

The pharmacology professor found a molecular pathway that could explain the nexus, although that needs to be confirmed.

"There's still a lot to be studied in order to really understand if B12 causes acne," she said.

The study found that, in the presence of vitamin B12, the skin bacteria that are commonly linked to acne start pumping out inflammatory molecules known to promote pimples.
In the study, scientists investigated the differences between skin bacteria from people prone to acne and bacteria from people with clear-skinned faces. The researchers looked at the bacteria's gene expression, hoping to figure out why Propionibacterium acnes, which is the most common skin microbe, causes pimples in some people but not in others.
They found that vitamin B12 changed the gene expression of the skin bacteria, which is what could have led to the acne-promoting inflammation.

British pilot first to take off in F35 using 'ski jump'

BAE Systems test pilot Peter Wilson flies F-35B from land based ski jump ramp for the first time. It is designed for vertical landing but not take-off.

The F-35 Lightning II – also known as the Joint Strike Fighter or JSF–  is a multirole aircraft project conceived and developed by the Pentagon since 1996 by manufacturer Lockheed Martin, with the principal partners Northrop Grumman and BAE Systems.

Below is a video taken early in June of the aircraft landing on an aircraft carrier flight deck during Marine Corps tests.

New dinosaur discovered in South Africa

A reconstruction of the new dinosaur's skeleton. [Credit: Wits University]

A reconstruction of the new dinosaur's skeleton. [Credit: Wits University]

South African and Argentinian palaeontologists have discovered a new 200 million year old dinosaur from South Africa, and named it Sefapanosaurus, from the Sesotho word "sefapano", meaning "cross".

The researchers from South Africa's University of Cape Town (UCT) and the University of the Witwatersrand (Wits University), and from the Argentinian Museo de La Plata and Museo Paleontológico Egidio Feruglio made the announcement in the scientific journal, Zoological Journal of the Linnaean Society.

The specimen was found in the late 1930s in the Zastron area of South Africa's Free State province, near the Lesotho border, but it had been lost among other fossils at Wits University.

When re-discovered a few years ago, scientists considered that it was the remains of another South African dinosaur, Aardonyx. Closer study since then has revealed that it is a completely new animal.

"The discovery of Sefapanosaurus shows that there were several of these transitional early sauropodomorph dinosaurs roaming around southern Africa about 200 million years ago," says Anusuya Chinsamy-Turan, co-author and Professor in the Department of Biological Sciences at UCT.

The dinosaur helps to fill the gap between the earliest sauropodomorphs and the gigantic sauropods, Dr Alejandro Otero, Argentinian palaeontologist and lead author, says.

"Sefapanosaurus constitutes a member of the growing list of transitional sauropodomorph dinosaurs from Argentina and South Africa that are increasingly telling us about how they diversified."

The remains of the Sefapanosaurus include limb bones, foot bones, and several vertebrae. 

PTSD may raise stroke and heart disease risk in women

[Credit: Getty Images]

[Credit: Getty Images]

Women who develop post-traumatic stress disorder (PTSD) may have a greater risk of future cardiovascular disease than women with no traumatic history, according to research published today in the American Heart Association journal Circulation.

In the first major study of PTSD and onset of cardiovascular disease – both heart attacks and strokes – exclusively in women, researchers examined about 50,000 participants in the Nurses' Health Study over 20 years.

The scientists found that women with four or more PTSD symptoms had 60% higher rates of cardiovascular disease compared to women who weren't exposed to traumatic events.

Women with no PTSD symptoms, but who reported traumatic events, had 45% higher rates of cardiovascular disease.

Almost half of the association between elevated PTSD symptoms and cardiovascular disease was accounted for by unhealthy behaviours such as smoking, obesity, lack of exercise and medical factors such as high blood pressure.

"PTSD is generally considered a psychological problem, but the take-home message from our findings is that it also has a profound impact on physical health, especially cardiovascular risk," said Jennifer Sumner, lead author from Columbia University.

"This is not exclusively a mental problem – it's a potentially deadly problem of the body as well."

Most studies of cardiovascular disease risk in PTSD patients have been conducted in men who have served in the military or among disaster survivors.

See also the Cosmos cover story on the surprising possible causes of PTSD, Healing a battle-scarred mind.

The retina's power supply that makes vision possible

Fluorescently labeled microtubules extend from the tips of the dendrites (top) into the axon and down into the giant synaptic terminal (bottom) of a single isolated goldfish retinal bipolar cell. A loop of microtubules encircles the inner plasma membrane of the terminal and anchors mitochondria. [Credit: Graffe et al., 2015]  

Fluorescently labeled microtubules extend from the tips of the dendrites (top) into the axon and down into the giant synaptic terminal (bottom) of a single isolated goldfish retinal bipolar cell. A loop of microtubules encircles the inner plasma membrane of the terminal and anchors mitochondria. [Credit: Graffe et al., 2015]

 

A thick band of microtubules in certain neurons in the retina help provide energy required for visual processing, researchers now believe.

The discovery of the pathways for mitochondria is published in The Journal of General Physiology.

The retina contains specialised neurons called bipolar cells that transmit information from light-sensitive photoreceptor cells to ganglion neurons, which send information to the brain for interpretation as images.

Unlike most neurons, bipolar cells are continuously active and so require a constant supply of energy. The discovery could explain how they do it.

researchers from the National Heart, Lung, and Blood Institute and Yale University used cutting-edge 3D microscopy to examine the subcellular architecture in retinal bipolar cells of live goldfish.

Unexpectedly, the team discovered a thick band of microtubules, a component of the cell's cytoskeleton, that extended from the axon of the neuron into the synaptic terminal and then looped around the interior periphery of the terminal.
The microtubule band appeared to associate with mitochondria – organelles known for providing energy to cells – in the synaptic terminal. When the researchers administered drugs to inhibit the movement of certain "motor" proteins that transport mitochondria and other cargo within the cell by traveling along microtubules, the mitochondria accumulated in the axon of the neuron and never made it to the synaptic terminal.
 

Hubble spots near-by planet bleeding giant cloud of hydrogen

An artist's concept shows an enormous comet-like cloud of hydrogen bleeding off of a warm, Neptune-sized planet just 30 light-years from Earth. [Credits: NASA, ESA, and G. Bacon (STScI)]

 

Astronomers using NASA's Hubble Space Telescope have discovered an immense cloud of hydrogen dubbed "The Behemoth" bleeding from a planet orbiting a nearby star.

The planet is about the size of Neptune and the cloud of gas 50 times as large.

enormous, comet-like feature is about 50 times the size of the parent star. The hydrogen is evaporating from a warm, Neptune-sized planet, due to extreme radiation from the star.

This phenomenon where hydrogen evaporates away due to the heat of a star has never been seen around a planet so small.

Astronomers say it may offer clues to how other planets with hydrogen-enveloped atmospheres could have their outer layers evaporated by their parent star, leaving behind solid, rocky cores.

"This cloud is very spectacular, though the evaporation rate does not threaten the planet right now," explains the study's leader, David Ehrenreich of the Observatory of the University of Geneva in Switzerland.

"But we know that in the past, the star, which is a faint red dwarf, was more active. This means that the planet evaporated faster during its first billion years of existence because of the strong radiation from the young star. Overall, we estimate that it may have lost up to 10 percent of its atmosphere over the past several billion years."

The planet, named GJ 436b, is considered to be a "Warm Neptune", because of its size and because it is much closer to its star than Neptune is to our sun. Although it is in no danger of having its atmosphere completely evaporated and stripped down to a rocky core, this planet could explain the existence of so-called Hot Super-Earths that are very close to their stars.

These hot, rocky worlds were discovered by the Convection Rotation and Planetary Transits (CoRoT) and NASA's Kepler space telescope. Hot Super-Earths could be the remnants of more massive planets that completely lost their thick, gaseous atmospheres to the same type of evaporation.

Because the Earth's atmosphere blocks most ultraviolet light, astronomers needed a space telescope with Hubble's ultraviolet capability and exquisite precision to find "The Behemoth."