Wednesday, January 4, 2017

A joint research team from the University of Calgary, American Museum of Natural History, and Florida State University announced on Monday that the eggs of non-avian dinosaurs such as the duck-billed dinosaur took as long as six months to hatch, far longer than had previously been believed.

Bird eggs incubate for 11 to 85 days, about half the time of most other egg-laying vertebrates. Scientists had thought dinosaur eggs were more like those of modern birds than modern reptiles, but this long hatch time is far more reminiscent of monitor lizard than magpie.

The scientists reached this conclusion by comparing CT scans of the teeth of dinosaur embryos of two different species, the Protoceratops andrewsi, which had eggs weighing under 200 grams, and Hypacrosaurus stebingeri, a type of duck-billed dinosaur that had eggs twenty times that size. They observed the von Ebner lines, patterns that form in vertebrate teeth as they grow, to determine how long the overall developmental process was taking. “They’re kind of like tree rings, but they’re put down daily,” said Florida State University co-author Gregory Erickson. “And so we could literally count them to see how long each dinosaur had been developing.” They found the Protoceratops embryo was about three months old and the Hypacrosaurus about six months.

According to the research team, this may be one reason why dinosaurs did not recover after the Cretaceous-Paleogene extinction event 65 million years ago. Both the eggs and any parents guarding them would have drawn the attention of predators and been unable to flee floods or other problems. Guardians might not have been able to move far to find food. This, researchers say, would have put dinosaurs at a disadvantage over animals with quicker-hatching eggs and their mammalian competitors.

Natural History Museum Curator and study co-author Mark Norell cites advances in imaging technology as the reason why this study is being published today: “We know very little about dinosaur embryology, yet it relates to so many aspects of development, life history, and evolution, [b]ut with the help of advanced tools like CT scanners and high-resolution microscopy, we’re making discoveries that we couldn’t have imagined 20 years ago.”

The research team plans to study more fossilized dinosaur embryo skeletons to confirm their findings. Specifically, the current study did not include the skeleton of a velociraptor or any other dinosaur considered closely related to birds.

Thursday, June 23, 2011

Greek Prime Minister George Papandreou survived a confidence vote by the Greek parliament late Tuesday night, thus allowing Papandreou to form a new cabinet constituted to address Greece’s severe financial debt crisis. The vote’s outcome is viewed as a measure of confidence in the government’s ability to resolve the problems of the deeply-indebted nation and implement the stringent austerity measures necessary for Greece to receive future bailout packages from the European Union (EU).

Papandreou managed to face down internal dissent within his own Panhellenic Socialist Movement over the extremely unpopular austerity measures (he has said the measures are an issue of “life or death”) and the final vote of 155 to 143, with two abstentions, matched Papandreou’s 155 seats. Meanwhile, Greeks were angrily demonstrating against the measures outside, throwing bottles at the parliament building as riot police stood by.

Following the confidence vote, Greece will be in a position to look for further financial aid from the EU to avoid defaulting on its enormous debt, but help from the EU is dependent on the real work that must be done first: the Greek parliament’s implementation of the hugely unpopular austerity measures.

Government spokesman Elias Mossialos said in an interview with Skai Television before the vote that Greece will be unable to pay wages and pensions after July 15 if the government does not secure the EU financing.

The vote came in the midst weeks of widespread anti-austerity protests and strikes in major cities throughout Greece, involving clashes between police and demonstrators angry with the proposed slew of layoffs in the public sector which are to accompany the Socialist cabinet’s program.

On Wednesday, Pimco, the biggest bond fund in the world, said it was unimpressed with Tuesday’s vote of confidence, saying it believes Greece and perhaps other European economies will ultimately default on their debts. Mohamed El-Erian, chief executive of Pimco, said, “Nothing has been done to enhance growth. No single (Greek) indicator has shown strength.”

“For the next three years, we’re going to see different economies work out different problems. For European economies, especially Greece, it would be through default,” said Mohamed El-Erian in a video conference.

The euro fell against the dollar on Wednesday as financial markets indicated that the eurozone debt crisis is far from over.

George Papandreou gave an emotional speech to parliament on Wednesday, saying “We have a unique opportunity (to change the country). If we falter, if we lose heart and squander it… history will judge us very harshly.”

Meanwhile, when the new austerity measures move to parliament for a vote, Greece’s major unions are planning to hold a 48-hour general strike.

Thursday, February 24, 2005

A paste containing synthetic tooth enamel can seal small cavities without drilling. Kazue Yamagishi and colleagues at the FAP Dental Institute in Tokyo say that the paste can repair small cavities in 15 minutes.

Currently, fillers don’t stick to such small cavities so dentists must drill bigger holes. Hydroxyapatite crystals, of which natural enamel is made, bond with teeth to repair tiny areas of damage.

Yamagishi and colleagues have tested their paste on a lower premolar tooth that showed early signs of decay. They found that the synthetic enamel merged with the natural enamel. The synthetic enamel also appears to make teeth stronger which will improve resistance to future decay. As with drilling, however, there is still the potential for pain: The paste is strongly acidic to encourage crystal growth and causes inflammation if it touches the gums.

The paste is reported in the journal Nature.