Friday, March 25, 2011
Thursday, March 24, 2011
Thriving long before the dinosaur age, Tiarajudens eccentricus was armed with an incredible arsenal of teeth for grinding, tearing, and even scaring. But the newly discovered saber-toothed mammal ancestor was a vegetarian, a new study says.Not only did the big-dog-size animal have huge canines—each as large as a crayon—but the roof of the animal's mouth appears to have been studded with teeth, which allowed for rapid replacement of lost teeth, as in sharks, researchers say.Part of the Anomodontia suborder within the Therapsida order—often called mammal-like reptiles—the 260-million-year-old fossil vegetarian "looks like a combination of different animals, and it takes some time to believe it when you see this animal in front of you," said paleontologist Juan Carlos Cisneros, who discovered the fossil in Brazil."It has the incisors of a horse, which are very good for cutting and pulling plants; the big molars of a capybara (picture), for grinding; and the canines of a saber-toothed cat."(Related: "'Social' Sabertooths Hunted in Packs, Study Says.")Paleontologist Jörg Fröbisch said the saber teeth are a particular surprise, considering the animal's diet of fibrous plants."You would usually expect saber teeth in a carnivore," said Fröbisch, of the Humboldt University of Berlin."The best known animals are obviously saber-toothed cats or tigers, but there are also some [extinct] forms known among the marsupials, relatives of kangaroos and wombats," added Fröbisch, who wasn't involved in the Tiarajudens eccentricus study, to be published tomorrow in the journal Science.T. eccentricus' saber teeth might have deterred predators or intimidated or wounded rivals of the same species, the study authors speculate."Saber teeth used for display or fighting between members of the same species is something that we thought appeared in herbivores less than 60 million years ago," said study leader Cisneros, of Brazil's Federal University of Piauí."If Tiarajudens eccentricus [used them this way], then it appeared much earlier, when terrestrial communities were ... dominated by herbivores."[...]These unique dental adaptations may also offer some clues to the striking success of the anomodonts during the middle Permian era, before dinosaurs dominated Earth. (See a prehistoric time line.)"Anomodonts were the most successful group of terrestrial vertebrates, with the most species, most diverse morphologies, and most ecological adaptations during this time," the University of Humboldt's Fröbisch said."There were burrowing forms, climbing forms, semiaquatic forms, small rat-sized animals, and large cow-sized animals in this same group, and this is unique in the ancestral lineage of mammals," he said.
ummm. They are not mammal ancestors!!! grr.
still cool though.
Wednesday, March 23, 2011
Atmospheric CO2 Effects of the Central Atlantic Magmatic Province Eruptions1. Schaller, M. F. (a)2. Wright, J. D. (a)3. D. V. Kent. (a,b,*)a. Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ, USA.b. Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, USA.* To whom correspondence should be addressed. E-mail: firstname.lastname@example.orgAbstract - The effects of a large igneous province on the concentration of atmospheric carbon dioxide (PCO2) are mostly unknown. In this study, we estimate PCO2 from stable isotopic values of pedogenic carbonates interbedded with volcanics of the Central Atlantic Magmatic Province (CAMP) in the Newark Basin, eastern North America. We find pre-CAMP PCO2 values of ~2000 parts per million (ppm), increasing to ~4400 ppm immediately after the first volcanic unit, followed by a steady decrease toward pre-eruptive levels over the subsequent 300 thousand years, a pattern that is repeated after the second and third flow units. We interpret each PCO2 increase as a direct response to magmatic activity (primary outgassing or contact metamorphism). The systematic decreases in PCO2 after each magmatic episode probably reflect consumption of atmospheric CO2 by weathering of silicates, stimulated by fresh CAMP volcanics.
Anyone have a copy? Again, LBNL doesn't subscribe to Science.
Ancient trash heaps gave rise to Everglades tree islands
Garbage mounds left by prehistoric humans might have driven the formation of many of the Florida Everglades' tree islands, distinctive havens of exceptional ecological richness in the sprawling marsh that are today threatened by human development.
Tree islands are patches of relatively high and dry ground that dot the marshes of the Everglades. Typically a meter (3.3 feet) or so high, many of them are elevated enough to allow trees to grow. They provide a nesting site for alligators and a refuge for birds, panthers, and other wildlife.
Scientists have thought for many years that the so-called fixed tree islands (a larger type of tree island frequently found in the Everglades' main channel, Shark River Slough) developed on protrusions from the rocky layer of a mineral called carbonate that sits beneath the marsh. Now, new research indicates that the real trigger for island development might have been middens, or trash piles left behind from human settlements that date to about 5,000 years ago.
These middens, a mixture of bones, food discards, charcoal, and human artifacts (such as clay pots and shell tools), would have provided an elevated area, drier than the surrounding marsh, allowing trees and other vegetation to grow. Bones also leaked phosphorus, a nutrient for plants that is otherwise scarce in the Everglades.
"This goes to show that human disturbance in the environment doesn't always have a negative consequence," says Gail Chmura, a paleoecologist at McGill University in Montreal, Canada, and one of the authors of the study.
Chmura will be presenting her research tomorrow, Tuesday 22 March, at the American Geophysical Union's Chapman Conference on Climates, Past Landscapes, and Civilizations. About 95 scientists have converged on Santa Fe this week to discuss the latest research findings from archeology, paleoclimatology, paleoecology, and other fields that reveal how changes in regional and global climate have impacted the development and fates of societies.
Study shows Native Americans modified American landscape years prior to arrival of Europeans
A new study by Baylor University geology researchers shows that Native Americans' land use nearly a century ago produced a widespread impact on the eastern North American landscape and floodplain development several hundred years prior to the arrival of major European settlements.
The study appears on-line in the journal Geology.
Researchers attribute early colonial land-use practices, such as deforestation, plowing and damming with influencing present-day hydrological systems across eastern North America. Previous studies suggest that Native Americans' land use in eastern North America initially caused the change in hydrological systems, however, little direct evidence has been provided until now.
The Baylor study found that pre-European so-called "natural" floodplains have a history of prehistoric indigenous land use, and thus colonial-era Europeans were not the first people to have an impact on the hydrologic systems of eastern North America. The study also found that prehistoric small-scale agricultural societies caused widespread ecological change and increased sedimentation in hydrologic systems during the Medieval Climate Anomaly–Little Ice Age, which occurred about 700 to 1,000 years ago.
"These are two very important findings," said Gary Stinchcomb, a Baylor doctoral candidate who conducted the study. "The findings conclusively demonstrate that Native Americans in eastern North America impacted their environment well before the arrival of Europeans. Through their agricultural practices, Native Americans increased soil erosion and sediment yields to the Delaware River basin."
The Baylor researchers found that prehistoric people decreased forest cover to reorient their settlements and intensify corn production. They also contributed to increased sedimentation in valley bottoms about 700 to 1,000 years ago, much earlier than previously thought. The findings suggest that prehistoric land use was the initial cause of increased sedimentation in the valley bottoms, and sedimentation was later amplified by wetter and stormier conditions.
The idea that the Americas were pristine prior to the arrival of Europeans is absolutely false. The Americas were actually an excellent example of an ecosystem that had just gone through a mass extinction. In essence, it is a disaster zone on a multicontinental scale. In the partially completed mass 6th extinction post. I'll get there. The therocephalian post progresses.
One the big questions that trouble cosmologists and particle physicists is the distribution of matter and antimatter in the Universe. It certainly looks is if matter dominates the cosmos but looks can be deceiving. We may just live in a corner of the universe that happens to be dominated by matter.Today, we find there's a little extra antimatter in our corner thanks to the work of the STAR collaboration at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory in the US.These guys banged together 10^9 gold nuclei at energies of 200 GeV and spotted 18 antinuclei of helium-4 in the ensuing wreckage. That's an impressive achievement by an standards--at the very least we now know antihelium-4 can exist.These kinds of impacts create a hot blob of more or less equal numbers of quarks and antiquarks, a so-called quark gluon plasma. This cools down forming various particles and their antiparticles.
no time. however, uber awesome.
Hmm. I wonder if there is AntiHeium-3, James? ;)
Lockheed Martin unveiled its suburban Denver Space Operations Simulation Center (SOSC) on March 21, a large development, evaluation and testing facility for NASA’s Orion/Multi-Purpose Crew Vehicle.Lockheed hopes to launch Orion on its first test flight in 2013 and prepare for congressionally mandated operations by the end of 2016.The 41,000-sq.-ft. environmentally friendly SOSC was constructed on deep Colorado bedrock, isolated from regional seismic disturbances, to provide a stable testing environment for the evaluation of precision instrumentation.Located at Lockheed Martin’s Waterton Facility, the new center hosts the first Orion ground test article, which was shipped from the company’s Michoud Assembly Facility in New Orleans in early February.The flightworthy test article will undergo performance testing at SOSC to recreate the conditions experienced during the ascent, launch abort, in orbit, re-entry, descent, parachute and water recovery regimes.Orion would be restricted to crew rescue duties at the International Space Station under the strategy outlined by President Obama last year. However, Congress favors the deep-space exploration mission designated by the NASA Authorization Act of 2010. The facility’s capabilities include Orion space station docking as well as asteroid encounter simulations.“Orion was designed from inception to fly multiple, deep-space missions,” says John Karas, vice president and general manager of Lockheed Martin’s Human Space Flight programs. “Our collective expertise in systems integration, planetary exploration and human spaceflight operations will help ensure success for our nation’s next-generation space transportation system.”
Lockheed also pitched a progressive space program around their Orion.
1. First Test Flight in 20132. A servicing flight to the International Space Station in 2016.3. A lunar flyby or an upgrade mission to the Hubble telescope in 2017.4. A flight to the Lagrange 2 point behind the Lunar farside in 2018.5. A 12 million kilometer voyage to the asteroid 2008 EA9 taking 195 days in 2019.6. An artificial gravity test using a tether in low Earth orbit in 2023.7. A 5 million kilometer voyage to the asteroid 2000 SG344 taking 450 days in 2029.8. A Mars orbital expedition that would focus on exploring the Martian Moon Deimos in the 2031-2035 time range.
Tuesday, March 22, 2011
Updated chronology for the Miocene hominoid radiation in Western Eurasia1. Isaac Casanovas-Vilar (a,1)2. David M. Alba (a)3. Miguel Garcés (b)4. Josep M. Robles (a,c)5. Salvador Moyà-Solà (d)a. Institut Català de Paleontologia, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spainb. Grup Geomodels, Departament d'Estratigrafia, Paleontologia i Geociències Marines, Facultat de Geologia, Universitat de Barcelona, 08028 Barcelona, Spainc. FOSSILIA Serveis Paleontològics i Geològics, 08470 Sant Celoni, Barcelona, Spaind. Institució Catalana de Recerca i Estudis Avançats, Institut Català de Paleontologia i Unitat d'Antropologia Biològica, Departament de Biologia Animal, Biologia Vegetal, i Ecologia, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain1. To whom correspondence should be addressed. E-mail: email@example.com.Abstract:Extant apes (Primates: Hominoidea) are the relics of a group that was much more diverse in the past. They originated in Africa around the Oligocene/Miocene boundary, but by the beginning of the Middle Miocene they expanded their range into Eurasia, where they experienced a far-reaching evolutionary radiation. A Eurasian origin of the great ape and human clade (Hominidae) has been favored by several authors, but the assessment of this hypothesis has been hampered by the lack of accurate datings for many Western Eurasian hominoids. Here we provide an updated chronology that incorporates recently discovered Iberian taxa and further reevaluates the age of many previously known sites on the basis of local biostratigraphic scales and magnetostratigraphic data. Our results show that identifiable Eurasian kenyapithecins (Griphopithecus and Kenyapithecus) are much younger than previously thought (ca. 14 Ma instead of 16 Ma), which casts serious doubts on the attribution of the hominoid tooth from Engelswies (16.3–16.5 Ma) to cf. Griphopithecus. This evidence is further consistent with an alternative scenario, according to which the Eurasian pongines and African hominines might have independently evolved in their respective continents from similar kenyapithecin ancestors, resulting from an early Middle Miocene intercontinental range extension followed by vicariance. This hypothesis, which would imply an independent origin of orthogrady in pongines and hominines, deserves further testing by accurately inferring the phylogenetic position of European dryopithecins, which might be stem pongines rather than stem hominines.
Friday, March 18, 2011
Thursday, March 17, 2011
Wednesday, March 16, 2011
Bursts of intense global warming that have lasted tens of thousands of years have taken place more frequently throughout history than previously believe, according to evidence gathered by a team led by Scripps Institution of Oceanography, UC San Diego researchers.Richard Norris, a professor of geology at Scripps who co-authored the report, said that releases of carbon dioxide sequestered in the deep oceans were the most likely trigger of these ancient "hyperthermal" events. Most of the events raised average global temperatures between 2° and 3° Celsius (3.6 and 5.4° F), an amount comparable to current conservative estimates of how much temperatures are expected to rise in coming decades as a consequence of anthropogenic global warming. Most hyperthermals lasted about 40,000 years before temperatures returned to normal.The study appears in the March 17 issue of the journal Nature."These hyperthermals seem not to have been rare events," Norris said, "hence there are lots of ancient examples of global warming on a scale broadly like the expected future warming. We can use these events to examine the impact of global change on marine ecosystems, climate and ocean circulation."The hyperthermals took place roughly every 400,000 years during a warm period of Earth history that prevailed some 50 million years ago. The strongest of them coincided with an event known as the Paleocene-Eocene Thermal Maximum, the transition between two geologic epochs in which global temperatures rose between 4° and 7° C (7.2° and 12.6° F) and needed 200,000 years to return to historical norms. The events stopped taking place around 40 million years ago, when the planet entered a cooling phase. No warming events of the magnitude of these hyperthermals have been detected in the geological record since then.Phil Sexton, a former student of Norris' now at the Open University in the United Kingdom, led the analysis of sediment cores collected off the South American coast. In the cores, evidence of the warm periods presented itself in bands of gray sediment layered within otherwise pale greenish mud. The gray sediment contained increased amounts of clay left after the calcareous shells of microscopic organisms were dissolved on the sea floor. These clay-rich intervals are consistent with ocean acidification episodes that would have been triggered by large-scale releases of carbon dioxide. Large influxes of carbon dioxide change the chemistry of seawater by producing greater amounts of carbonic acid in the oceans.The authors concluded that a release of carbon dioxide from the deep oceans was a more likely cause of the hyperthermals than other triggering events that have been hypothesized. The regularity of the hyperthermals and relatively warm ocean temperatures of the period makes them less likely to have been caused by events such as large melt-offs of methane hydrates, terrestrial burning of peat or even proposed cometary impacts. The hyperthermals could have been set in motion by a build-up of carbon dioxide in the deep oceans caused by slowing or stopping of circulation in ocean basins that prevented carbon dioxide release.
No time. Curious though.
“For over a century, the people of Puerto Rico and the United States have woven a lasting political, economic, social, and cultural relationship. Today, this relationship is strengthened and renewed by more than four million U.S. citizens who call Puerto Rico home and nearly equal number of Puerto Ricans living on the mainland who travel back to Puerto Rico for business, vacation, or visits to see family and friends,” Obama said in a letter released with the report. “We honor their contributions to the nation and welcome their vigorous participation in helping to develop, shape, and implement the recommendations presented in this report.”The 122-page report places an emphasis on the island’s economic and social issues, but opens with a 7-point series of recommendations on Puerto Rico’s century-old status dilemma.[...]The Task Force recommends that all relevant parties — the president, Congress, and the leadership and people of Puerto Rico — statehood, independence, free association, and commonwealth — and have that will acted upon by the end of 2012 or soon thereafter.The Task Force leans slightly toward a two-tier plebiscite process that “allows the people of Puerto Rico first to vote on the question of whether they wish to be part of the United States or wish to be independent, and then to choose between the available status options, as limited by the outcome of the first vote.”“If the process produces a clear result, Congress should act on it quickly with the president’s support,” the Task Force said.In a position that is sure to ruffle some feathers, the Task Force recommends that only residents of Puerto Rico should be eligible to vote in a status plebiscite.
Here we go again.
Intriguing, especially since there is the anticipation that more stealth fighters are on their way to be revealed, but at the same time, be aware folks that it is easy to photoshop things these days. This is a flyover in a very populated area, so there ought to be more pix soon.
Few specimens inspire greater thrills among fossil collectors than a complete trilobite. These ancient arthropods – relatives of lobsters, spiders and insects – went extinct more than 250 million years ago, but are sometimes found in beautifully preserved condition. In rare instances, an entire population of trilobites is found fossilized together. Carlton E. Brett finds evidence for ancient environment and behavior in these mass graves.Brett, University of Cincinnati professor of geology, will present his findings March 20 at the Geological Society of America regional meeting in Pittsburgh, in a paper co-authored with Adrian Kin of Poland's Institute of Geological Sciences at Jagiellonian University, and Brenda Hunda of the Cincinnati Museum Center.In a quest that has taken him from Oklahoma to Morocco and Poland, Brett has analyzed multiple examples of mass trilobite burial. A smothering death by tons of hurricane-generated storm sediment was so rapid that the trilobites are preserved in life position. These geologic "snapshots" record behavior in much the way that ancient Roman life was recorded at Pompeii by volcanic ash.Burial was rapid, Brett said, but also somewhat delicate. Trilobites, like other arthropods, shed their hard exoskeletons from time to time."We find molted pieces lying immediately adjacent to each other," he said. "This is proof that the sediments were not significantly disturbed after burial."Like modern crabs and lobsters, trilobites appear to have gathered in large groups for protection when they shed their protective exoskeletons. During molting, there was safety in numbers. And, like their modern cousins, trilobites seem to have used these molting gatherings as opportunities for mating.The mass burials preserve large groups of similar-sized – and therefore similarly aged – specimens, segregated by species and, after molting, "naked.""It's an orgy," Brett said.
Note, this is similar to what horseshoe crabs do in modern times. Its described a bit less salaciously though.
Tuesday, March 15, 2011
Monday, March 14, 2011
For most of us, setting the clock forward in the spring is a sad occasion, a sign that we're losing an hour of sleep.Daylight saving time begins Sunday at 2 a.m. in most of the U.S. -- except for Hawaii and Arizona.But for some genetically blessed people, a loss of one hour of sleep is not a problem. In fact, sleeping fewer than the recommended seven or eight hours is the norm. They naturally feel refreshed and ready to go -- at 4 a.m.These "short sleepers" have a mutation on a gene known as hDEC2, that regulates their sleep-wake cycle. This mutation allows them to function on less sleep, researchers say.
Huh. My dad worked on almost zilch sleep or so it seemed to me when I was a kid -> teen. He'd be in bed late, if I woke up at 2 am he would often be still up, and get up relatively early.
Once I hit my 30s, I started doing this, too; I didn't used to though. In fact, last night I was up until 1:30 AM and got up at 5:30 AM. I'm a bit bleary at first, but I'm more than fully functional by 6 am: I had my family's lunches, breakfasts, and whatnot all done by then as well as having eaten. I've been doing this now for over 3 years as I have pursued the GLXP. I'm tired and sometimes irritable, but I am far more than merely functional, even without caffeine.
I'm also what I've termed an old campaigner to my wife as far as sleep goes. If I lay down and I want to, I go to sleep. This drives my wife nuts. I can get up and take care of something int he middle sleeping and I am back asleep in seconds after laying down.
There are a few times I can't sleep, but they are few and far between. Likewise, I don't start passing out until I've been up for 20 hours now. I can go to sleep earlier, but don't need to. Alnighters are tough though, but then, I am 37 now rather than 19. ;)
I do wonder if I'd test positive for the gene though.
I also wonder about the family's male longevity...despite its very poor lifestyle choices.
It seems like akidnognathanidae was trying really hard to be the therocephalian equivalent of carnivora and bauriodea was trying to be rodentia.
Parallel evolution and all that.
For the first time, I've seen a name attached to the J-20: the Black Eagle. Eagle seems to be an obvious and common name for fighters. The F-15 Eagle is the 4th generation American air superiority fighter. The Russians through Sukhoi built the Su-47/S-37 Berkut (or Golden Eagle). Interestingly and somewhat contrary to stereotype, Russian tank project was also called the Black Eagle.
On to the news, The J-20 has been called a production prototype by the Chinese military. Its status whether it was a one off R&D aircraft or a real deal prototype has been in question. It now seems to truly a production prototype. If it is true and their development program goes smoothly enough, they will be set for IOC between 2018 to 2020.
A tangental aspect of the whole hoopla over the J-20 is the policy and politics behind it. There seems to be a question of just how much the Chinese civilian government actually knew about the J-20. Apparently, they gave the impression, right or wrong, that they didn't know about the unveiling of the J-20 to the world when the SecDef Gates came for a visit. This raised the phantom of just how much control the Chinese government has over the PLA. Im unsure how serious to take this, but...it's provocative. One would hope that we are not seeing a Japan pre WW2 developing here. That's both frightening and ironic, if a bit doubtful.
Friday, March 11, 2011
Interesting. Not that different than what I've heard otherwise.
Keep in mind that Benjamin Franklin's writings, he railed against the nonwhite immigrants moving into the US and corrupting its culture. Those immigrants? Germans. Yep. Germans. He considered the English, certain Germans (Saxons, iirc), Dutch and perhaps the Scots to be white. No one else was. 100 years ago, Italians and Irish were not "white" by general American social standards. They are definitely considered such today. What is 'white' and what is not is a moving standard. Dr Lee points that out in an interesting manner.
It appears that the definite of 'white' is moving to encompass asians and latinos. By 2035 or 2040, it may well be that being Mexican is no different than Italian. Or Irish. The differences would absorbed and some kept by society as a whole and some not, just like any other immigrant group in the past once the flow from the point of origin has slowed to a trickle. Had we still be getting waves of Italians from the late 19th century all the way to the present, our societal uneasiness might still be present.
Unfortunately, developments make it look like, as Dr Lee points out again, that white is going to be excluding black in the life trajectories of those within their categories. Listen to the short above. Its a bit depressing. Black is the underclass. Sad and depressing that.
Oxygen isotopes of East Asian dinosaurs reveal exceptionally cold Early Cretaceous climatesAuthors:1. Romain Amiot (a,1,2)2. Xu Wang (b),3. Zhonghe Zhou (a)4. Xiaolin Wang (a)5. Eric Buffetaut(c)6. Christophe Lécuyer(d,2)7. Zhongli Ding(b)8. Frédéric Fluteau(e)9. Tsuyoshi Hibino(f)10. Nao Kusuhashi(g)11. Jinyou Mo(h)12. Varavudh Suteethorn(i)13. Yuanqing Wang(a)14. Xing Xu (a)15. Fusong Zhang(b)Institutions:a) Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (CAS), 142 Xi Zhi Men Wai DaJie, Beijing 100044, China;b) Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, 19 Beitucheng Xilu, Beijing 100029, China;c) CNRS (Centre National de la Recherche Scientifique) UMR (Unité Mixte de Recherche) 8538, Laboratoire de Géologie de l’Ecole Normale Supérieure, 24, Rue Lhomond, 75231 Paris Cedex 05, France;d) CNRS (Centre National de la Recherche Scientifique) UMR (Unité Mixte de Recherche) 5125, Université Claude Bernard Lyon 1, 2, Rue Raphaël Dubois, 69622 Villeurbanne Cedex, France;e) Institut de Physique du Globe de Paris, 1 Rue Jussieu, 75238 Paris Cedex 05, France;f) Shiramine Institute of Paleontology, Kuwajima, Hakusan, Ishikawa 920-2502, Japan;g) Department of Earth's Evolution and Environment, Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan;h) Faculty of Earth Sciences, China University of Geosciences, 388 Lumo Road, Wuhan 430074, China;i)Department of Mineral Resources, Rama VI Road, Bangkok 10400, ThailandAbstract:Early Cretaceous vertebrate assemblages from East Asia and parti- cularly the Jehol Biota of northeastern China flourished during a period of highly debated climatic history. While the unique charac- ters of these continental faunas have been the subject of various speculations about their biogeographic history, little attention has been paid to their possible climatic causes. Here we address this question using the oxygen isotope composition of apatite phos- phate (δ18 Op ) from various reptile remains recovered from China, Thailand, and Japan. δ18Op values indicate that cold terrestrial cli- mates prevailed at least in this part of Asia during the Barremian— early Albian interval. Estimated mean air temperatures of about 10 ` 4 °C at midlatitudes (∼42 °N) correspond to present day cool temperate climatic conditions. Such low temperatures are in agree- ment with previous reports of cold marine temperatures during this part of the Early Cretaceous, as well as with the widespread occurrence of the temperate fossil wood genus Xenoxylon and the absence of thermophilic reptiles such as crocodilians in north- eastern China. The unique character of the Jehol Biota is thus not only the result of its evolutionary and biogeographical history but is also due to rather cold local climatic conditions linked to the paleolatitudinal position of northeastern China and global icehouse climates that prevailed during this part of the Early Cretaceous.
Interesting. And it makes sense. This is not the first time that there has been a deviation from the hot house model for the Cretaceous. I'm reading the paper slowly because I have a lot to do. However, take a look. Link in the title, as always.
Thursday, March 10, 2011
Global warming devastated tropical rainforests 300 million years ago. Now scientists report the unexpected discovery that this event triggered an evolutionary burst among reptiles -- and inadvertently paved the way for the rise of dinosaurs, 100 million years later.This event happened during the Carboniferous Period. At that time, Europe and North America lay on the equator and were covered by steamy tropical rainforests. But when the Earth's climate became hotter and drier, rainforests collapsed, triggering reptile evolution.Dr Howard Falcon-Lang of Royal Holloway, University of London, UK explained: "Climate change caused rainforests to fragment into small 'islands' of forest. This isolated populations of reptiles and each community evolved in separate directions, leading to an increase in diversity."Professor Mike Benton of the University of Bristol, UK added: "This is a classic ecological response to habitat fragmentation. You see the same process happening today whenever a group of animals becomes isolated from its parent population. It's been studied on traffic islands between major road systems or, as Charles Darwin famously observed in the Galapagos, on oceanic islands."Ms Sarda Sahney, also of the University of Bristol, UK said: "It is fascinating that even in the face of devastating ecosystem-collapse, animals may continue to diversify through the creation of endemic populations." However, she warned that: "Life may not be so lucky again in the future, should the Amazon rainforest collapse."To reach their conclusions, the scientists studied the fossil record of reptiles before and after rainforest collapse. They showed that reptiles became more diverse and even changed their diet as they struggled to adapt to rapidly changing climate and environment.
One of the building blocks for the next generation of quantum computing and communications systems is a way of storing and regenerating photonic qubits. These are generally encoded in the polarisation of photons.To date, physicists have done this by transferring the qubit from a photon to an ensemble of quantum particles such as a crystal lattice or a small cloud of atoms.Today, Holger Specht and pals at the Max Planck Institute for Quantum Optics in Garching, Germany, have gone one better. They've found a way to store the qubit from a polarised photon in a single atom of rubidium and then release it again later.The trick here is first to find an atom with the suitable two-level state that will absorb photons in the right way and second, to find a way to force the photon to give up its qubit to the atom.It turns out that rubidium has the just right energy levels. Specht and co force the atom and photon to interact by trapping them in a high quality mirrored cavity in which the photon can enter but not easily escape. It then rebounds inside until it gives up its goods to the atom.To accept the qubit, the atom first has to be placed in the right state by a weak laser beam. A second laser beam later forces the atom to spit out the qubit in the form of an identical polarised photon.The result is a single atom memory that can read, store and write quantum information.
Wednesday, March 09, 2011
Title: The Occurrence Rate of Earth Analog Planets Orbiting Sunlike StarsAuthors: Joseph Catanzarite and Michael Shao, Jet Propulsion Laboratory, California Institute ofTechnologySummary paragraphKepler is a space telescope that searches Sun-like stars for planets. Its major goal is to determine ߟா௧, the fraction of Sunlike stars that have planets like Earth. When a planet ‘transits’ or moves in front of a star, Kepler can measure the concomitant dimming of the starlight. From analysis of the first four months of those measurements for over 150,000 stars, Kepler’s science team has determined sizes, surface temperatures, orbit sizes and periods for over a thousand new planet candidates. Here, we show that 1.4% to 2.7% of stars like the Sun are expected to have Earth analog planets, based on the Kepler data release of Feb 2011. The estimate will improve when it is based on the full 3.5 to 6 year Kepler data set. Accurate knowledge of ߟா௧ is necessary to plan future missions that will image and take spectra of Earthlike planets. Our result that Earths are relatively scarce means that a substantial effort will be needed to identify suitable target stars prior to these future missions.
Again, no time.
Almost 2,000 years ago, 19 Roman soldiers rushed into a cramped underground tunnel, prepared to defend the Roman-held Syrian city of Dura-Europos from an army of Persians digging to undermine the city's mudbrick walls.But instead of Persian soldiers, the Romans met with a wall of noxious black smoke that turned to acid in their lungs. Their crystal-pommeled swords were no match for this weapon; the Romans choked and died in moments, many with their last pay of coins still slung in purses on their belts.Nearby, a Persian soldier — perhaps the one who started the toxic underground fire — suffered his own death throes, grasping desperately at his chain mail shirt as he choked.These 20 men, who died in A.D. 256, may be the first victims of chemical warfare to leave any archaeological evidence of their passing, according to a new investigation. The case is a cold one, with little physical evidence left behind beyond drawings and archaeological excavation notes from the 1930s. But a new analysis of those materials published in January in the American Journal of Archaeology finds that the soldiers likely did not die by the sword as the original excavator believed. Instead, they were gassed.
no time, but kewl.
Tuesday, March 08, 2011
Japan plans to fly a prototype by 2014. That's pretty ambitious. See a bit more here.
Apparently, the Russians are planning midlife (or early life) engine upgrade for the PAK-FA/T-50 fighter once it is in frontline service. Supposedly, the avionics of the PAK-FA are ... incredible. Not necessarily in a positive meaning of that word...The Russians are also working on the PAK-DA program to build a new bomber by 2017. There's a bit of an update over the older information here.
Somehow I missed posting this earlier, but the Chinese may have other stealth aircraft to reveal here shortly beyond the J-20.
India is now working on (besides the PAK-FA with the Russians) an equivalent of the F-35. Its very early in the game, but...
The US has kicked off a relatively near term next gen bomber program (and here). The idea being to actually start fielding the bomber circa 2018, if I am reading this stuff right. That's shockingly quick given the timeline for the F-22 development (1983-2005? IOC), F-35 (1995-2015+ IOC) and others. In fact, this very aggressive timeline has led to a lot of speculation that the airframe has already flown (and originally here) and that all they are doing is ironing out the bits requiring integration rather than developing new tech. There is a lot of speculation as to what the capabilities will be: lasers? drone control? hypersonic missiles (in a role like the SRAM)? What is its true purpose as well?
Japan. Russia. China. India. USA. Where is Europe?
Friday, March 04, 2011
Thursday, March 03, 2011
Evidence for a diversified sea-based economy among North American inhabitants dating from 12,200 to 11,400 years ago is emerging from three sites on California's Channel Islands.Reporting in the March 4 issue of Science, a 15-member team led by University of Oregon and Smithsonian Institution scholars describes the discovery of scores of stemmed projectile points and crescents dating to that time period. The artifacts are associated with the remains of shellfish, seals, geese, cormorants and fish.Funded primarily by grants from the National Science Foundation, the team also found thousands of artifacts made from chert, a flint-like rock used to make projectile points and other stone tools.Some of the intact projectiles are so delicate that their only practical use would have been for hunting on the water, said Jon Erlandson, professor of anthropology and director of the Museum of Natural and Cultural History at the University of Oregon. He has been conducting research on the islands for more than 30 years."This is among the earliest evidence of seafaring and maritime adaptations in the Americas, and another extension of the diversity of Paleoindian economies," Erlandson said. "The points we are finding are extraordinary, the workmanship amazing. They are ultra thin, serrated and have incredible barbs on them. It's a very sophisticated chipped-stone technology." He also noted that the stemmed points are much different than the iconic fluted points left throughout North America by Clovis and Folsom peoples who hunted big game on land.The artifacts were recovered from three sites that date to the end of the Pleistocene epoch on Santa Rosa and San Miguel islands, which in those days were connected as one island off the California coast. Sea levels then were 50 to 60 meters (about 160-200 feet) below modern levels. Rising seas have since flooded the shorelines and coastal lowlands where early populations would have spent most of their time.Erlandson and his colleagues have focused their search on upland features such as springs, caves, and chert outcrops that would have drawn early maritime peoples into the interior. Rising seas also may have submerged evidence of even older human habitation of the islands.
Wednesday, March 02, 2011
With the steep decline in populations of many animal species, from frogs and fish to tigers, some scientists have warned that Earth is on the brink of a mass extinction like those that occurred only five times before during the past 540 million years.Each of these 'Big Five' saw three-quarters or more of all animal species go extinct.In a study to be published in the March 3 issue of the journal Nature, University of California, Berkeley, paleobiologists assess where mammals and other species stand today in terms of possible extinction, compared with the past 540 million years, and they find cause for hope as well as alarm."If you look only at the critically endangered mammals – those where the risk of extinction is at least 50 percent within three of their generations – and assume that their time will run out, and they will be extinct in 1,000 years, that puts us clearly outside any range of normal, and tells us that we are moving into the mass extinction realm," said principal author Anthony D. Barnosky, UC Berkeley professor of integrative biology, a curator in the Museum of Paleontology and a research paleontologist in the Museum of Vertebrate Zoology."If currently threatened species – those officially classed as critically endangered, endangered and vulnerable – actually went extinct, and that rate of extinction continued, the sixth mass extinction could arrive within as little as 3 to 22 centuries," he said.Nevertheless, Barnosky added, it's not too late to save these critically endangered mammals and other such species and stop short of the tipping point. That would require dealing with a perfect storm of threats, including habitat fragmentation, invasive species, disease and global warming,"So far, only 1 to 2 percent of all species have gone extinct in the groups we can look at clearly, so by those numbers, it looks like we are not far down the road to extinction. We still have a lot of Earth's biota to save," Barnosky said. "It's very important to devote resources and legislation toward species conservation if we don't want to be the species whose activity caused a mass extinction."Coauthor Charles Marshall, UC Berkeley professor of integrative biology and director of the campus's Museum of Paleontology, emphasized that the small number of recorded extinctions to date does not mean we are not in a crisis."Just because the magnitude is low compared to the biggest mass extinctions we've seen in a half a billion years doesn't mean to say that they aren't significant," he said. "Even though the magnitude is fairly low, present rates are higher than during most past mass extinctions.""The modern global mass extinction is a largely unaddressed hazard of climate change and human activities," said H. Richard Lane, program director in the National Science Foundation's Division of Earth Sciences, which funded the research. "Its continued progression, as this paper shows, could result in unforeseen – and irreversible – negative consequences to the environment and to humanity."The study originated in a graduate seminar Barnosky organized in 2009 to bring biologists and paleontologists together in an attempt to compare the extinction rate seen in the fossil record with today's extinction record. These are "like comparing apples and oranges," Barnosky said. For one thing, the fossil record goes back 3.5 billion years, while the historical record goes back only a few thousand years. In addition, the fossil record has many holes, making it is impossible to count every species that evolved and subsequently disappeared, which probably amounts to 99 percent of all species that have ever existed. A different set of data problems complicates counting modern extinctions.Dating of the fossil record also is not very precise, Marshall said."If we find a mass extinction, we have great difficulty determining whether it was a bad weekend or it occurred over a decade or 10,000 years," he said. "But without the fossil record, we really have no scale to measure the significance of the impact we are having."To get around this limitation, Marshall said, "This paper, instead of calculating a single death rate, estimates the range of plausible rates for the mass extinctions from the fossil record and then compares these rates to where we are now."Barnosky's team chose mammals as a starting point because they are well studied today and are well represented in the fossil record going back some 65 million years. Biologists estimate that within the past 500 years, at least 80 mammal species have gone extinct out of a starting total of 5,570 species.The team's estimate for the average extinction rate for mammals is less than two extinctions every million years, far lower than the current extinction rate for mammals."It looks like modern extinction rates resemble mass extinction rates, even after setting a high bar for defining 'mass extinction,'" Barnosky said.
In short, yes. A bit longer answer, it started over 30k years ago and is anthropogenic in nature.
I have a post that is in very early form on this, but it will be a while before it sees the light of day.
Tuesday, March 01, 2011
There's an interesting bun fight that has started. It has to do with whether or not there is a correlation between the rapid rise in oxygen during the Devonian and the evolution of large bodied predatory fish. Oxygen levels did, in fact, rise significantly during the Devonian. Large bodied fish that filled the predator niche also arose then.
This has been playing out in PNAS. The original paper raised the suggestion that there was a direct correlation. A researcher wrote an objection. The original researchers responded.
There is a long ongoing argument about how much the environment and the geophysical systems influence evolution. Some feel that it has overwhelming evidence in support of this. The idea that the environment is the driver of evolution is very common. Sometimes a change in climate would be a driver in evolution: the general cooling and drying at the end of the Eocene and into the Oligocene, for example. Others, as above, have suggested that the oxygen levels have been another driver. Desertification, temperature rise, etc have all been pitched as important drivers.
Others have some strong objections to this. Butterfield is a good example above. Another noted individual that you may recognize is John Hawks. He frequently objects to the idea that the environment was the driver behind human evolution.
I have to wonder. There are times when I object too when it seems like the authors are overstretching. That seems to happen alot in this realm. The grand handwave seems to be pretty common, nevermind those details. On the other hand, it seems hard to deny that the environment isn't one of the greatest, if not the greatest driver of evolution. It can and does wipe out populations of various species. It has wiped out whole ecosystems before, thereby terminating their participation in following evolutionary tales.
Sometimes the objections seem silly. Sometimes the handwavium is near violating causality. Either way, I caution that people ought to look at the details before objecting or accepting a theory.
Given the limited feedback I've received, I'm working on two paleo posts.
The first is the therocephalian overview; however, the theros are more diverse than either the dicyns or the gorgons. There appear to be five clades worth detailing and that will require more work with less material than on the gorgons or the dicyns.
The second post will be on the archaen environment, if I can get to it. I am rather busy with the team phoenicia stuff these days.