227 research outputs found
A Description of a New \u3cem\u3eAllosaurus\u3c/em\u3e (Dinosauria: Theropoda) Skull with Comparison to Additional Specimens
Allosaurus was a genus of large theropod dinosaur from the Late Jurassic Period (Kimmeridgian to early Tithonian). The history of the taxonomic classification of Allosaurus species is muddled at best, and the number of recognized species varies significantly between researchers. Most Allosaurs from the Morrison Formation are typically lumped into a single species, Allosaurus fragilis. Given the amount of variation seen in Allosaurs through the Morrison, the genus may more diverse than generally recognized. A nearly complete Allosaurus skull (CM 279) located in the Creation Museum in Petersberg, KY is described, with comparison of its skull morphology to two other well-known Allosaurus skulls at the Dinosaur National Monument (DNM 2560) in Jensen, Utah, and the Museum of the Rockies (MOR 693) in Bozeman, Montana. Similarities are noted between CM 297 and DNM 2560, which share the same rectangular muzzle shape, differing from the pointed muzzle and triangular skull of MOR 693. This difference suggests CM 297 and DNM 2560 belong to a different species than MOR 693, which potentially belongs to the recently described A. jimmadsenni, though more research into this classification is needed. Furthermore, CM 297 and DNM 2560, while classified as Allosaurus fragilis, show a notable difference from the neotype for A. fragilis, AMNH 4734. This difference is often attributed to supposed taphonomic distortion in AMNH 4734, though this claim may be erroneous
Understanding Feathered Dinosaurs
Young-earth creationists hold to separate creations of birds and land animals due to a literal interpretation of Genesis 1:20-25, which describes their creations on different days. As such, they oppose the conventional model of theropod-to-bird evolution. For many years, there were few Mesozoic birds known, namely Hesperornis and Icthyornis. Specimens such as Archaeopteryx, found in 1861, seemed to strengthen the argument for the proposed transition. However, even after John Ostrom reinvigorated the idea of dinosaur-to-bird evolution in 1960 with the discovery of Deinonychus, evidence of this transition was still sparse. In the 1990âs, exquisitely-preserved dinosaur fossils began to pour out of Liaoning Province, China sporting feathers and several feather-like filaments. Typical creationist responses to feathered dinosaur fossils include 1) denying that they are real fossils, 2) assuming that âdino-fuzzâ is something other than integument, or 3) arbitrarily calling some fossils birds and others dinosaurs. Some creationists believe that no feathered dinosaurs have been found, despite there being evidence of feathers in most families within Theropoda
Understanding Feathered Dinosaurs
Young-earth creationists hold to separate creations of birds and land animals due to a literal interpretation of Genesis 1:20-25, which describes their creations on different days. As such, they oppose the conventional model of theropod-to-bird evolution. For many years, there were few Mesozoic birds known, namely Hesperornis and Icthyornis. Specimens such as Archaeopteryx, found in 1861, seemed to strengthen the argument for the proposed transition. However, even after John Ostrom reinvigorated the idea of dinosaur-to-bird evolution in 1960 with the discovery of Deinonychus, evidence of this transition was still sparse. In the 1990âs, exquisitely-preserved dinosaur fossils began to pour out of Liaoning Province, China sporting feathers and several feather-like filaments. Typical creationist responses to feathered dinosaur fossils include 1) denying that they are real fossils, 2) assuming that âdino-fuzzâ is something other than integument, or 3) arbitrarily calling some fossils birds and others dinosaurs. Some creationists believe that no feathered dinosaurs have been found, despite there being evidence of feathers in most families within Theropoda
On the Aquatic Habits of Sauropods â An Antiquated Theory in Need of Revival?
When sauropods were first discovered, they were thought to have been restricted to life in the water due to their immense size. This image of sauropods was dismissed in the 1950âs when it was determined that the lungs would have been placed under massive amounts of pressure at these depths, rendering breathing nearly impossible (Kermack, 1951). However, these experiments failed to consider pneumaticity of sauropod vertebrae and were later dismissed. Sauropods possessed pneumatic features in all their presacral vertebrae, originally identified as weight-saving structures. These features kept the strength and integrity of the bone while dramatically reducing its weight. The postcranial skeletal pneumaticity is indicative of a physical relationship between the vertebral column and the pulmonary system. In particular, neosauropods show signs of air sacs in the lower back and hip regions (Wedel, 2003). A similar phenomenon is exhibited in modern birds. Other sauropods, by contrast, only possess such pneumatic features in the cervical vertebrae. The effects of a highly pneumatized skeleton on a sauropodâs buoyancy were not considered until the 1970âs. Henderson (2004) concluded in his study on sauropod buoyancy that it would be impossible for sauropods to walk in water deeper than chest-height, as their high calculated buoyancy would cause the animal to capsize. While Henderson (2004) and Kermack (1951) came to reasonable conclusions, perhaps the idea of semi-aquatic sauropods should not be ruled out. If this hypothesis were to be investigated further, there are several criteria scientists might consider. For instance, perhaps sauropods possessed reinforced peripheral airways that allowed their lungs to collapse when under higher pressures, similar to those in deep-diving whales and sealsâ something that is difficult to preserve in the fossil record. Additionally, if sauropods had a higher muscle mass than generally assumed, it would negatively affect the animalsâ buoyancy calculated in Hendersonâs (2004) experiments, helping to ballast the animal and prevent capsizing. These proposed adaptations are theoretical, and would not be preserved in the fossil record. Overall, the evidence painting sauropods as exclusively terrestrial animals is based on assumptions that perhaps should be reconsidered in light of some of these proposed adaptations
Rescuing Avoidable Consequences from the Clutches of Remedies and Placing it in Apportionment of Liability, Where it Belongs
Winning the Baldrige Award: How the Henry Ford Health System Undertook a FiveâYear Improvement Process
Henry Ford Health Systems (HFHS) won the 2011 Baldrige Award, a major accomplishment. This achievement resulted from a systemwide focus on minimizing and controlling medical errors, a cultural shift to stimulate innovation and creative problem solving, and service excellence at every level. The fiveâyear effort centered on meeting Baldrige Award criteria, typically utilized in the forâprofit setting. When applied to the nonprofit sector, HFHS managed to reduce costs, reduce medication and treatment errors, introduce multiple creative clinical programs, and launch a new Ritz Carltonâquality, hotelâstyle service.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102080/1/21088_ftp.pd
Microstructures Produced by Hadrosaur Bones from Alaska and Wyoming
Since 2005 when Dr. Mary Schweitzer made the first discovery, microstructures with the appearance of âosteocytesâ and âblood vesselsâ have been recovered from fossils of various localities, dating back as far as the Triassic. The majority of these finds have come from dense, cortical bone but recently have been discovered in cancellous bone. Since her initial discovery, Schweitzer has done a lot of work to verify that these microstructures are not biofilms, but instead are original organic tissue. This project was looking to get similar results to Schweitzerâs research and to find a simple test method for the initial discovery of soft tissue using easily available supplies. Fragments of âfloatâ Edmontosaurus bones were collected from Eastern Wyoming and âin-situâ hadrosaur bones collected from Alaska. Two different techniques were used, the first method implemented daily changes of a 0.5 M solution of EDTA and the second was a solution of 2M HCl; both are known techniques for demineralizing modern bone. Using the solution of HCl, the bones were subjected to daily solution changes until completely demineralized. The sediment left over was then used to make covered slides, which were then analyzed and photographed with a petrographic scope. This analysis revealed certain microstructures of several types that had been freed from the bone. Comparing the microstructures with previous work done by other researchers indicates that these structures have the morphological appearance of original soft tissue blood vessels and osteocytes. In every HCl sample, the material from Wyoming produced highly fragmented sections of these âblood vesselsâ, while the Alaska material produced larger, abundant âblood vesselsâ and in addition, rarer âosteocytesâ. These samples were of cancellous bone and ossified tendon. The EDTA samples have yet to produce any original organic structures. Further stain tests will be performed for verification of the organic nature of the structures. The ease in finding these microstructures using basic supplies and in weathered bones seems to indicate the possibility of original organic preservation in fossil bones may be quite prevalent, possibly even the norm
Gene expression changes with differentiation of cord blood stem cells to respiratory epithelial cells: a preliminary observation
Deleterious Mutation Burden and Its Association with Complex Traits in Sorghum (Sorghum bicolor)
Sorghum (Sorghum bicolor L.) is a major food cereal for millions of people worldwide. The sorghum genome, like other species, accumulates deleterious mutations, likely impacting its fitness. The lack of recombination, drift, and the coupling with favorable loci impede the removal of deleterious mutations from the genome by selection. To study how deleterious variants impact phenotypes, we identified putative deleterious mutations among âŒ5.5 M segregating variants of 229 diverse biomass sorghum lines. We provide the whole-genome estimate of the deleterious burden in sorghum, showing that âŒ33% of nonsynonymous substitutions are putatively deleterious. The pattern of mutation burden varies appreciably among racial groups. Across racial groups, the mutation burden correlated negatively with biomass, plant height, specific leaf area (SLA), and tissue starch content (TSC), suggesting that deleterious burden decreases trait fitness. Putatively deleterious variants explain roughly one-half of the genetic variance. However, there is only moderate improvement in total heritable variance explained for biomass (7.6%) and plant height (average of 3.1% across all stages). There is no advantage in total heritable variance for SLA and TSC. The contribution of putatively deleterious variants to phenotypic diversity therefore appears to be dependent on the genetic architecture of traits. Overall, these results suggest that incorporating putatively deleterious variants into genomic models slightly improves prediction accuracy because of extensive linkage. Knowledge of deleterious variants could be leveraged for sorghum breeding through either genome editing and/or conventional breeding that focuses on the selection of progeny with fewer deleterious alleles
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