Paleontology

Congressional Republicans say they support the U.S. military’s laser weapons and directed-energy programs designed to protect troops by zapping apart potential threats, from incoming rockets to drones flying overhead.A panel of the House Armed Services Committee singled out the Army’s Solid State Laser Testbed and the Navy’s Laser Weapon System as “items of special interest” in its draft of the 2014 defense authorization bill, which sets policy goals and spending targets for the fiscal year beginning Oct. 1.“The committee stresses the importance of directed energy research and encourages the Army’s continuation of those efforts,” according to language approved May 22 by the Intelligence, Emerging Threats and Capabilities Subcommittee, headed by Rep. Mac Thornberry, R-Texas.The panel similarly backed the Navy program, including the service’s plans to deploy the Laser Weapon System, or LaWS, aboard the amphibious transport dock USS Ponce early next year for further testing.It will be the first such deployment of the system after completing test shots last summer aboard the destroyer USS Dewey. The solid-state, infrared beam burned up dummy drones in evaluations in the Pacific Ocean off the coast of California.The legislation would require the secretaries of the Army and Navy to brief lawmakers on the demonstration programs and provide more information about the potential challenges of adopting the technology for wider use within the services, given its high-energy requirements.

Mature specimen of Rhapydionina deserta, from Loeblich & Tappan (1964). Calcareous foraminiferans have been featured on this site before: planktic floaters, living stars, microscopic jelly moulds and gigantic reef-formers. All these forms have belonged to the group of calcareous forams known as the rotaliids. Today's subject is another group of forams, the Rhapydionininae, belonging to a different calcareous group, the Miliolida. Miliolids may have shell walls made of calcite like the rotaliids, but differ in the wall structure: while the walls of rotaliids are glass-like and porous, those of miliolids are structured like porcelain. Phylogenetic studies of forams have not placed the miliolids close to the rotaliids, and the two groups seem to have evolved their secreted shells independently (Sen Gupta 2002). Rhapydionina liburnica, from Loeblich & Tappan (1964). The Rhapydionininae were defined by Loeblich & Tappan (1964) as a group of miliolids with a conical test composed of broad chambers stacked one on top of another (the overall shape being kind of like a fan or an ice-cream cone), with each of these chambers subdivided by internal septa into multiple chamberlets (the difference between a 'chamber' and a 'chamberlet' being that the latter are not completely divided from each other by the walls). The opening of the test took the form of a sieve-like array of pores at the top end. However, subsequent researchers have discovered that Loeblich & Tappan's definition was inadequate. Rhapydioninines start life growing as a flat spiral, with growth becoming linearised at maturity. However, it turns out that not all Rhapydionininae become linear; some retain their juvenile coiling into maturity (Vicedo et al. 2011). At least some species are believed to have both a linear megalospheric form and a coiled microspheric form. To explain, forams can be divided between microspheric forms, in which the first chambers of a new test are much smaller, and megalospheric forms with larger initial chambers. In those relatively few forams whose life cycles have been studied in detail, these two forms correspond to an alternation of generations, with a mostly microspheric asexually-reproducing generation giving rise to the generally megalospheric sexually-reproducing phase. Loeblich & Tappan's (1964) concept of rhapydionines, therefore, would have potentially placed members of a single species into separate families. Diagram of internal structure of two adult chambers of Cuvillierinella, from Vicedo et al. (2011). Key to abbreviations: ap f = apertural face, c chl = cortical chamberlets, flo = floor, m chl = medullar chamberlet, prp = preseptal space, rpi = residual pillars, s = septum, sl = septulum. Rhapydionines are best known as fossils, with a definite range from the Upper Cretaceous to the mid-Eocene (Loeblich & Tappan 1984). Believe it or not, whether there are still rhapydioninines in the world is something of an open question. Loeblich & Tappan (1964) listed two Recent genera in the Rhapydionininae, each represented by only a single known specimen. Ripacubana conica was originally described from sand deposits in Cuba; however, Loeblich & Tappan (1964) suggested that Ripacubana may actually represent what has been referred to as a 'zombie taxon'. Some of you may be familiar with the palaeontological concept of a 'Lazarus taxon', where a species disappears from the fossil record only to reappear at a later date. What has actually happened in these cases is that the species had only become locally extinct, but survived in some other locality that has not been preserved, subsequently recolonising its old range. A 'zombie taxon', however, is one that has genuinely become extinct at the earlier date, but its fossilised remains have since been transported into a younger sediment deposit, giving the impression that it survived later than it did*. In the case of Ripacubana, it is difficult to know just how long a foram shell b

Mitochondria are the cell’s workhorse, transforming the calories we eat into useable energy. They have also been the subject of lots of scrutiny over longevity, since lifespan is intimately tied up with metabolism. Now a new study reports that mitochondrial malfunction may actually be the key to extending life.Although loss of mitochondrial function has been associated with increased lifespan in a number of species, the reasons behind this effect have been poorly understood. It’s also been known that low levels of stress within a cell—for instance, running on low energy—can increase an animal’s lifespan. Most of these studies have however been done in flies, worms and yeast. Thus a Swiss research team led by Riekelt Houtkooper decided to examine stress and longevity in mice, as well as the worm C. elegans.In mice, they analyzed a set of related mouse strains that have lots of natural variation in lifespan—they live anywhere from 1 to 2 1/2 years. With genetic tests the researchers were able to pin down three specific genes that seemed to be the key determinants of the mouse’s lifespan. Mice with lower activity in these genes lived up to 2.5 times longer than those with high activity.Then, in worms, the researchers artificially damped down the activity of the equivalent genes and observed how long they lived. One gene stuck out as most important: Worms with a dampened mrps-5 gene lived 60 percent longer than normal.The key, the researchers say, appears to be that loss of mrps-5 causes the mitochondria to send a kind of cellular SOS to the nucleus. The nucleus’s response, called the “mitochondrial unfolded protein response,” is to send out protective proteins. This is interesting. It also runs contrary to the family history. We have very long lived folks in the family, but its in the patrilineal side of things. The men live fairly long, often inspite of their lifestyles rather than because of them. That would seem to preclude the source of longevity being a mitochondria based source. Rather it would argue to be a y linked trait. Interesting if we might be carrying something else. What happens if you combine them (assuming we haven't just been lucky).

THE INFLUENCE OF THERMAL EVOLUTION IN THE MAGNETIC PROTECTION OF TERRESTRIAL PLANETS Authors:1. Jorge I. Zuluaga (a) 2. Sebastian Bustamante (a) 3. Pablo A. Cuartas (a) 4. Jaime H. Hoyos (b)Affiliations:a. Instituto de Física-FCEN, Universidad de Antioquia, Calle 67 No. 53-108, Medellín, Colombiab. Departamento de Ciencias Básicas, Universidad de Medellín, Carrera 87 No. 30-65, Medellín, Colombia Abstract:Magnetic protection of potentially habitable planets plays a central role in determining their actual habitability and/or the chances of detecting atmospheric biosignatures. Here we develop a thermal evolution model of potentially habitable Earth-like planets and super-Earths (SEs). Using up-to-date dynamo-scaling laws, we predict the properties of core dynamo magnetic fields and study the influence of thermal evolution on their properties. The level of magnetic protection of tidally locked and unlocked planets is estimated by combining simplified models of the planetary magnetosphere and a phenomenological description of the stellar wind. Thermal evolution introduces a strong dependence of magnetic protection on planetary mass and rotation rate. Tidally locked terrestrial planets with an Earth-like composition would have early dayside magnetopause distances between 1.5 and 4.0 Rp , larger than previously estimated. Unlocked planets with periods of rotation ~1 day are protected by magnetospheres extending between 3 and 8 Rp . Our results are robust in comparison with variations in planetary bulk composition and uncertainties in other critical model parameters. For illustration purposes, the thermal evolution and magnetic protection of the potentially habitable SEs GL 581d, GJ 667Cc, and HD 40307g were also studied. Assuming an Earth-like composition, we found that the dynamos of these planets are already extinct or close to being shut down. While GL 581d is the best protected, the protection of HD 40307g cannot be reliably estimated. GJ 667Cc, even under optimistic conditions, seems to be severely exposed to the stellar wind, and, under the conditions of our model, has probably suffered massive atmospheric losses.

In addition to the actual fossils, I do have a decent record of seeing live animals while out in the field, and the DPP and environs of the Tyrrell were no exception. The dinosaurs are of course, awesome, but it’s nice to see some wildlife too. Mark Graham had mentioned in his guest post that I’d been snapping some of the fauna, so now seemed a good time to bring them out First off is the easy one, these ground squirrels infest the area around the Tyrrell and this guy was literally sat on the front steps begging for food. While I didn’t give him any, the pot belly on this one and those that were hanging around make it quite obvious that plenty of people do, though just a few yards away other locals were much more shy and sveldt. Just traces here, but quite cool that you have coyote and deer (presumably mule deer given their abundance) going in opposite directions, though of course who knows how far apart in time. The canid also has some nice overprinting going on such that the two feet have left what appears to be one large, but rather odd, footprint. And here’s a pronghorn. A male rather obviously, and something I’d long wanted to see. I didn’t realise their range was this far north, so were a complete surprise to me when we came across a small group and I’ve got some nice photos of them mooching around. And here are some of those mule deer. This was part of a herd of a dozen or so, though there were plenty of odd ones or pairs seen from time to time in various places both around the museum and out into the wilds. I did see white-tailed deer too, but didn’t get any great photos. A real prize for me, a nice big bunny. I assume this is a jackrabbit, but I don’t actually know. I really like rabbits in general and have seen desert hares a couple of times in the wilds of China, but they tend to explode out of cover and vanish over the horizon before I realise I’ve spooked one, whereas this one was kind enough to move not too fast and stop a couple of times allowing me to get decent snaps (though out of tons that are out of focus or suffering from motion blur). And finally a chipmunk, one of many hanging around in the woods near Don Henderson’s house, though I was also surprised to see them out in boulder fields too. I saw traces of activity from beavers and porcupines on several trees (and a couple of roadkill of the latter) but sadly no live ones were around. I think pretty much all of these bar the chipmunk were new to me, not just in the wild, but in zoos too. Perhaps as they are considered too ‘boring’ or ‘normal’ for most collections, and if the US doesn’t bother, then they’re not too likely to end up in Europe or Asia either, so this was really a pretty good haul by my standards.

A reevaluation of Sigilmassasaurus brevicollis (Dinosauria) from the Cretaceous of MoroccoAuthors: 1. Bradley McFeeters (a)2. Michael J. Ryan (a)3. Sanja Hinic-Frlog (b) 4. Claudia Schröder-Adams (a)Affiliations:a. Dept. of Earth Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada.b. Dept. of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada.Abstract:The original hypodigm of the controversial mid-Cretaceous Moroccan dinosaur Sigilmassasaurus brevicollis is redescribed, and the diagnosis of the taxon is revised. Unambiguously referred material is restricted to cervical and anterior dorsal vertebrae sharing apomorphies with the holotype. A newly recognized diagnostic character of Sigilmassasaurus is the absence of anterior and posterior interzygapophyseal laminae of the neural arch, so that the neural spine directly meets the dorsal margin of the neural canal. A phylogenetic analysis supports the inclusion of Sigilmassasaurus in Tetanurae but not in Carcharodontosauridae. Sigilmassasaurus is distinct from all other theropods known from comparable material and is thus retained as a valid taxon.

Google Glass isn’t ready for prime time. Even Google knows this, which is why it hasn't shipped to the masses yet. Instead, Google floated a few units to “Explorers,” glorified guinea pigs who can enjoy the joys and trials of this cuttingest edge of cutting edge technologies. But nascent or not, Glass exists, and it works. Or at least it "works." Developers are still getting their feet wet, high-profile apps like Twitter and Facebook feel more like experiments than finished products, and bugs aren’t the exception, they’re the rule. But, you know, the thing turns on, and hears you say "Okay, Glass," and eagerly awaits your next command. Beyond the home screen, it’s up to Glass Explorers to wade through the good apps, the bad apps, and the broken apps, and we're right there with them. We went exploring, and this is what Glass can do; right here, right now.And for those of you without Glass, hopefully we can help you live vicariously through our misadventures and humble GIF illustrations. Glass is a strange beast, and it can take a while to get used to and understand what it’s trying to do. Maybe we’ll make you jealous, or maybe you’ll decide Glass is a worthless piece of trash. Either way, we hope we can shed light on the mystery, the wonder, and the social awkwardness that is Glass.We’ll be updating this list as new apps come out, and old apps are updated or made obsolete, so keep checking back. And if you see an app we haven’t covered yet, make sure to let us know!

Vegetable lamb, as illustrated in The Travels of Sir John Mandeville (ca 1360). Medieval legend in Europe spoke of a strange animal that could supposedly be found far off in central Asia: the vegetable lamb. According to legend, this was an animal much like an ordinary sheep except that it grew directly from a plant, to which it remained attached by the umbilical cord. The vegetable lamb would sustain itself by grazing on nearby vegetation but when this was depleted, as the lamb could not move away from the plant to which it was attached, the lamb would die. How such a pointlessly self-defeating organism was supposed to persist does not appear to have concerned the medieval lexicographers; presumably it was supposed to be allegorical of something. Opening fruit of Gossypium hirsutum, photographed by B. P. Schuiling. Part of the reason for the legend's persistence, however, was that there was indeed a form of 'wool' that came from a plant: cotton. The cotton genus Gossypium comprises about fifty species found in tropical and subtropical regions around the world (Wendel et al. 2010). Members of the genus vary from herbaceous perennials to small trees. The genus is divided into four subgenera, most of which are geographically distinct. The subgenus Gossypium is found in Africa and Arabia, subgenus Sturtia in Australia, and subgenus Houzingenia in the Americas. These three subgenera between them include the diploid cotton species; the fourth subgenus Karpas is also found in the Americas but differs in containing tetraploid species. Genetic evidence indicates that the subgenus Karpas arose at some point in the very recent past (within the last one or two million years) from a single hybridisation event between a species of subgenus Gossypium and one of Houzingenia, probably as a result of some chance dispersal event from Africa. Gossypium seeds seem well suited to dispersal: seeds of the Hawaiian Island species G. tomentosum have apparently germinated after being kept immersed in artificial seawater for three years (Wendel et al. 2010)! This same predicection for dispersal has resulted in the tetraploid species rapidly becoming widespread despite their recent origin, and in producing two species in remote locales: the Hawaiian G. tomentosum is directly related to the mainland G. hirsutum, while the Galapagos G. darwinii is sister to the mainland G. barbadense. Levant cotton Gossypium herbaceum, photographed by H. Zell. Commercial cotton is grown from four species of Gossypium, which may have each been domesticated independently in prehistoric times. All Gossypium species produce seeds with a covering of fuzzy hairs, but seeds of the two Old World diploid species G. herbaceum and G. arboreum also possess an outer layer of longer, flatter hairs that can be woven into thread. It was one of these two species, or possibly some now-extinct close relative, that made the crossing over the Atlantic to become one ancestor of the tetraploid species; as a result, the tetraploid species also possess these long outer hairs. Two of the tetraploid species, G. barbadense and G. hirsutum, were also domesticated, and the latter of these is now by far the most abundant cotton species in cultivation*. *In case you were wondering, no-one seems to have suggested that the island species related to the two American domesticates might have been human-dispersed. Sturt's desert rose Gossypium sturtianum, from here. Other diploid Gossypium species do not possess this longer outer hair layer, only the inner short layer, and are not sources of commercial cotton (though hybrids with some of these species have been used to breed desirable genetic traits into the commercial species). In one group of Australian species (the section Grandicalyx) found in the Kimberley region of northern Western Australia, the hair layer has become very sparse and the seeds are almost hairless. These seeds also possess fatty bodies called eliosomes that are

The mighty T. rex may have thrashed its massive head from side to side to dismember prey, but a new study shows that its smaller cousin Allosaurus was a more dexterous hunter and tugged at prey more like a modern-day falcon."Apparently one size doesn't fit all when it comes to dinosaur feeding styles," said Ohio University paleontologist Eric Snively, lead author of the new study published today in Palaeontologia Electronica. "Many people think of Allosaurus as a smaller and earlier version of T. rex, but our engineering analyses show that they were very different predators."Snively led a diverse team of Ohio University researchers, including experts in mechanical engineering, computer visualization and dinosaur anatomy. They started with a high-resolution cast of the five-foot-long skull plus neck of the 150-million-year-old predatory theropod dinosaur Allosaurus, one of the best known dinosaurs. They CT-scanned the bones at O'Bleness Memorial Hospital in Athens, which produced digital data that the authors could manipulate in a computer.Snively and mechanical engineer John Cotton applied a specialized engineering analysis borrowed from robotics called multibody dynamics. This allowed the scientists to run sophisticated simulations of the head and neck movements Allosaurus made when attacking prey, stripping flesh from a carcass or even just looking around."The engineering approach combines all the biological data—things like where the muscle forces attach and where the joints stop motion—into a single model. We can then simulate the physics and predict what Allosaurus was actually capable of doing," said Cotton, an assistant professor in the Russ College of Engineering and Technology.To figure out how Allosaurus de-fleshed a Stegosaurus, the team had to "re-flesh" Allosaurus. The anatomical structure of modern-day dinosaur relatives, such as birds and crocodilians, combined with tell-tale clues on the dinosaur bones, allowed Snively and anatomists Lawrence Witmer and Ryan Ridgely to build in neck and jaw muscles, air sinuses, the windpipe and other soft tissues into their Allosaurus 3D computer model."Dinosaur bones simply aren't enough," said Witmer, Chang Professor of Paleontology in the Heritage College of Osteopathic Medicine and principal investigator on the National Science Foundation's Visible Interactive Dinosaur Project that provided funding for this research. "We need to know about the other tissues that bring the skeleton to life."A key finding was an unusually placed neck muscle called longissimus capitis superficialis. In most predatory dinosaurs, such as T. rex, which Snively studied previously, this muscle passed from the side of the neck to a bony wing on the outer back corners of the skull."This neck muscle acts like a rider pulling on the reins of a horse's bridle," explained Snively. "If the muscle on one side contracts, it would turn the head in that direction, but if the muscles on both sides pull, it pulls the head straight back."But the analysis of Allosaurus revealed that the longissimus muscle attached much lower on the skull, which, according to the engineering analyses, would have caused "head ventroflexion followed by retraction.""Allosaurus was uniquely equipped to drive its head down into prey, hold it there, and then pull the head straight up and back with the neck and body, tearing flesh from the carcass … kind of like how a power shovel or backhoe rips into the ground," Snively said.In the animal world, this same de-fleshing technique is used by small falcons, such as kestrels. Tyrannosaurs like T. rex, on the other hand, were engineered to use a grab-and-shake technique to tear off hunks of flesh, more like a crocodile.But the team's engineering analyses revealed a cost to T. rex's feeding style: high rotational inertia. That large bony and toothy skull perched at the end of the neck made it hard for T. rex to speed up or slow down its head or to change its course as it swung its head around