4,442 research outputs found

    Interactions between adult migratory striped bass (Morone saxatilis) and their prey during winter off the Virginia and North Carolina Atlantic coast from 1994 through 2007

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    The migratory population of striped bass (Morone saxatilis) (>400 mm total length[TL]) spends winter in the Atlantic Ocean off the Virginia and North Carolina coasts of the United States. Information on trophic dynamics for these large adults during winter is limited. Feeding habits and prey were described from stomach contents of 1154 striped bass ranging from 373 to 1250 mm TL, collected from trawls during winters of 1994-96, 2000, and 2002-03, and from the recreational fishery during 2005-07. Nineteen prey species were present in the diet. Overall, Atlantic menhaden (Brevoortia tyrannus) and bay anchovy (Anchoa mitchilli) dominated the diet by boimass (67.9%) and numerically (68.6%). The percent biomass of Atlantic menhaden during 1994-2003 to 87.0% during 2005-07. Demersal fish species such as Atlantic croaker (Micropogonias undulatus) and spot (Leiostomus xanthurus) represented <15% of the diet biomass, whereas alosines (Alosa spp.) were rarely observed. Invertebrates were least important, contributing <1.0% by biomass and numerically. Striped bass are capable of feeding on a wide range of prey sizes (2% to 43% of their total length). This study outlines the importance of clupeoid fishes to striped bass winter production and also shows that predation may be exerting pressure on one of their dominant prey, the Atlantic menhaden

    Do Efl Students Like Graded Readers?

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    Graded readers are widely used in English as a foreign language programs, but we have little information about whether students find them interesting. In this study, 14 to 16 year old students of English as a foreign language in Taiwan were asked to evaluate the readers they had read. Overall, 41% found the books to be interesting, and 24% did not, but only 4% strongly agreed that the books were interesting. This is an encouraging result, but if our goal is to help students find truly compelling reading material, we will have to look elsewhere for additional reading material

    Do Efl Students Like Graded Readers?

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    Graded readers are widely used in English as a foreign language programs, but we have little information about whether students find them interesting. In this study, 14 to 16 year old students of English as a foreign language in Taiwan were asked to evaluate the readers they had read. Overall, 41% found the books to be interesting, and 24% did not, but only 4% strongly agreed that the books were interesting. This is an encouraging result, but if our goal is to help students find truly compelling reading material, we will have to look elsewhere for additional reading material

    Recent Experimental and Clinical Findings in the Skeleton Associated with Loss of Estrogen Hormone or Estrogen Receptor Activity

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    Studies on rodent models and rare human disorders of estrogen production or response have revealed an increased complexity of the actions of estrogen on bone. ERalpha disruption in human males results in delayed epiphyseal maturation, tall stature, trabecular thinning, marked cortical thinning, genu valgum and significantly reduced cortical vBMD, but trabecular number is preserved and there is normal to increased periosteal expansion. Aromatase deficiency results overall in a similar phenotype, although less is known about skeletal architecture. Importantly, estrogen replacement in these individuals, even if provided late in the third decade, may normalize aBMD. Less certain is whether there is complete recovery of normal skeletal architecture and strength. Rodent models, in general, are consistent with the human phenotype but are confounded by inherent differences between mouse and human physiology and issues regarding the completeness of the different knock-out lines. Both human and rodent studies suggest that residual effects of estrogen through ERbeta, truncated ERalpha forms or nonclassical estrogen receptors might account for different phenotypes in the hERKO man, aromatase deficient subjects and rodents. Importantly, androgen, particularly by preserving trabecular number and augmenting both periosteal and epiphyseal growth, also has significant actions on bone

    New early Eocene vertebrate assemblage from western India reveals a mixed fauna of European and Gondwana affinities

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    AbstractThe Ypresian Cambay Shale Formation at Vastan and Mangrol lignite mines in Gujarat, western India, has yielded a rich vertebrate fauna with numerous taxa of European affinities. Here we report a new, approximately contemporary vertebrate assemblage from two fossiliferous layers in the nearby mine of Tadkeshwar. These layers have yielded a similar mammal fauna with the co-occurrence of the perissodactyl-like cambaytheriid Cambaytherium thewissi, the adapoid primates Marcgodinotius indicus and cf. Asiadapis cambayensis, and the hyaenodontid Indohyaenodon raoi. The presence of these species in both Vastan and Tadkeshwar mines and at different levels suggests that the deposits between the two major lignite seams represent a single land mammal age. Apart from the aforementioned species there is a new, smaller species of Cambaytherium, and a new genus and species of esthonychid tillodont. This fauna also contains the first large early Eocene vertebrates from India, including an unidentified Coryphodon-like pantodont, a dyrosaurid crocodyliform and a new giant madtsoiid snake. Among the Tadkeshwar vertebrates several taxa are of Gondwana affinities, such as Pelomedusoides turtles, dyrosaurids, and large madtsoiids, attesting that the early Eocene was a crucial period in India during which Laurasian taxa of European affinities co-existed with relict taxa from Gondwana before the India-Asia collision. Our results suggest that terrestrial faunas could have dispersed to or from Europe during episodes of contact between the Indian subcontinent and different island blocks along the northern margin of the Neotethys, such as the Kohistan–Ladakh island-arc system. Gondwana taxa might represent remnants of ghost lineages shared with Madagascar, which reached the Indian subcontinent during the late Cretaceous; alternatively they might have come from North Africa and passed along the southern margin of the Neotethys to reach the Indian subcontinent. These dispersals would have been possible as a result of favourable paleogeographic conditions such as the particular Neotethys conformation during the beginning of the early Eocene

    A New Adapoid Primate From The Early Eocene Of India

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    http://deepblue.lib.umich.edu/bitstream/2027.42/57497/1/Vol 31 No 14 final 12-19-07.pd

    Magnus Effect in Duct Flow

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    The following research paper details the preliminary research carried out by this team. The project was originally conceived to determine if Magnus Lift could be utilized in an unconventional way to assist rockets during takeoff. Several conceptual designs were proposed, but the idea was scrapped when it became apparent that the team would not be able to generate the desired lift without inducing significant amounts of drag and additional weight on a rocket. Instead, the team focused on researching an interesting topic that hasn’t been previously explored: Magnus lift on a cylinder within a duct. An experimental procedure that could be carried out in a wind tunnel at the University of Akron was designed along with several models for a test fixture. In order to predict the results of the experiment, several preliminary CFD simulations were performed. Unfortunately, due to limited time and resources, the test fixture was not built and the experiment was not carried out. However, more detailed simulations were performed. Unfortunately, the results suggested that minimal lift is generated on a duct/cylinder system compared to a spinning cylinder in open air. Several potential applications for utilizing the Magnus effect were suggested, such as assisting rockets during takeoff, or allowing trains to enter curves at higher speeds without derailing. Although Magnus effect in duct flow would likely provide negligible benefits, the potential uses for Magnus lift in open air are promising

    Fusarium wilt of banana: Global problems and perspectives

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    Fusarium wilt of banana is recognized as one of the most destructive diseases of banana worldwide. In addition to an overview of the history of research into fusarium wilt of banana, a precis of the current global problems posed by this disease to producers and consumers of bananas is presented in this paper. Key issues and opportunities facing scientific researchers in their attempts to find solutions to the management of this disease are also discussed, with reference to the notion of sustainable agriculture
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