1,841 research outputs found

    Distribution of Fishes in the James River in North Dakota and South Dakota Prior to Garrison and Oahe Diversion Projects

    Get PDF
    Forty-one species of fish representing 12 families were collected in ®et» 1975, frost the James l i w r basin in Bortli Bakhta smd Sooth Dakota* additional. 18 species and two additional families were reported fey ot’tr estimators* Only three species were present in the headwater region * ®r species appeared downstream in progressive additions to the header assemblage, Some species differed from the general addition pata and showed a localized habitat preference. $11 ration, nutrient i f ^ # \u3e / - 4 ^ .. ;\u27,rvy-vi . ;v 3* low-head dams, and. loss of streamflow are believed to have changed .. \u3c • yy- /* Sgtj? , , , \u27 V J »} *\u27 ;j- i , river and affected fish species. Winterkill, conditions under no or flow limited the number of fish e_ecies in the upper portion of the *r. The addition of diverted water to the James River will reduce pers of low flow, and fish species may occupy portions of the upstream ir in which their present, survival is impossible or seasonally limited, se may be transferred to the Red River of the Korth (Hudson Bay drainage mgh the irrigation connection at Oakes, Mcrfch Dakota. Fifteen James *r species do not occur in the Red River of the North

    Public Relations

    Get PDF

    Nonlinear resonant tunneling of Bose-Einstein condensates in tilted optical lattices

    Full text link
    We study the tunneling decay of a Bose-Einstein condensate out of tilted optical lattices within the mean-field approximation. We introduce a novel method to calculate also excited resonance eigenstates of the Gross-Pitaevskii equation, based on a grid relaxation procedure with complex absorbing potentials. This algorithm works efficiently in a wide range of parameters where established methods fail. It allows us to study the effects of the nonlinearity in detail in the regime of resonant tunneling, where the decay rate is enhanced by resonant coupling to excited unstable states.Comment: Revised and enlarged version, including 1 additional figur

    Comparison of four statistical methods for detection of a major gene in a progeny test design

    Get PDF
    In livestock improvement it is common to design a progeny test of sires in order to estimate their breeding values. The data recorded for these estimate are useful for the detection of major genes. They are the n.m performances Yij of m progeny j of n sires i. These data need to be corrected for the polygenic influence of the sire on its progeny (sire i effect Ui). Four statistical tests of the segregation of a major gene are compared. The first (ﺎSA for "segregation analysis") is the classical ratio of the likelihoods under Ho (no major gene) and H1 (a major gene is segregating). The parameters describing the population (means and standard deviations within genotype) are estimated by maximizing the marginal likelihood of the Yij. The other statistics studied are approximations of this ﺎSA statistic where the sire i effect (Ui) is considered as a fixed effect (ﺎ FE statistic) or, following Elsen et al. (1988) and Höschele (1988), where the parameters, and Ui, are estimated maximizing the joint likelihood of Ui and Yij (ﺎME and ﺎME2 statistics). Simulation studies were done in order to describe the distribution of these statistics. It is shown that ﺎSA and ﺎME1 are the most powerful test, followed by ﺎME2 whose relative loss of power ranged between 20 and 40%, depending on the H1 case studied, when 400 progeny are measured (n = m = 20). The segregation analysis, based on direct maximization of the likelihood, required 30 times more computation time than the ﺎME test using an EM algorithm.Il est fréquent, en sélection, de tester sur descendance, des mâles, afin d’estimer leur valeur génétique. Les données recueillies dans ce but peuvent être utilisées afin de mettre en évidence un gène majeur. Elles sont constituées des n.m performances Yij de m descendants j de n mâles i. Ces données doivent être corrigées pour l’effet polygénique du père (Ui) sur ses descendants. Quatre tests statistiques de mise en évidence d’un tel gène majeur sont comparés. Le premier (ﺎSA pour "segregation analysis") est le rapport classique des vraisemblances sous Ho (pas de gène majeur) et sous H1 (existence d’un gène majeur). Les paramètres caractéristiques de la population (moyennes et écarts types intragénotype) sont estimés en maximisant la vraisemblance marginale des Yij Les autres statistiques de tests sont des approximations de ﺎSA pour lesquelles, soit l’effet père Ui est considéré comme un effet fixé (test IFE) soit, comme proposé par Elsen et al. (1988) et Höschele (1988), les paramètres, et Ui, sont obtenus en maximisant la vraisemblance conjointe des Yij et des Ui (test ﺎME1 et ﺎME2 Nous avons réalisé des simulations afin de décrire les distributions de ces tests. ﺎSA et ﺎME1 sont les tests les plus puissants, suivi par ﺎME2 dont la perte relative de puissance varie entre 20 et 40% selon l’hypothèse H1 étudiées, quand 400 descendants sont mesurés (n = m =20). L’analyse de ségrégation, réalisée par maximisation directe de la vraisemblance, demande 30 fois plus de temps de calcul que les tests ﺎME réalisés l’aide d’un algorithme EM

    Structural analysis of Salmonella enterica effector protein SopD

    Get PDF
    Salmonella outer protein D (SopD) is a type III secreted virulence effector protein from Salmonella enterica. Full-length SopD and SopD lacking 16 amino acids at the N-terminus (SopDDeltaN) have been expressed as fusions with GST in Escherichia coli, purified with a typical yield of 20-30 mg per litre of cell culture and crystallized. Biophysical characterization has been carried out mainly on SopDDeltaN. Analytical size exclusion chromatography shows that SopDDeltaN is monomeric and probably globular in aqueous solution. The secondary structure composition, calculated from the CD spectrum, is mixed (38% alpha-helix and 26% beta-strand). Sequence analysis indicates that SopD contains a coiled coil motif, as found in numerous other type III secretion system-associated proteins. This suggests that SopD has the potential for one or more heterotypic protein-protein interactions. Limited trypsin digestion of SopDDeltaN, monitored by both one-dimensional proton NMR spectroscopy and SDS-PAGE, shows that the protein has a large, protease-resistant core domain of 286 amino acid residues. This single-domain architecture suggests that SopD lacks a cognate chaperone. In crystallization trials, SopDDeltaN produced better crystals than either full-length SopD or trypsin-digested SopDDeltaN. Diffraction to 3.0 Angstrom resolution has so far been obtained from crystals of SopDDeltaN

    Real-time optical micro-manipulation using optimized holograms generated on the GPU

    Full text link
    Holographic optical tweezers allow the three dimensional, dynamic, multipoint manipulation of micron sized dielectric objects. Exploiting the massive parallel architecture of modern GPUs we can generate highly optimized holograms at video frame rate allowing the interactive micro-manipulation of 3D structures.Comment: 13 pages, 8 figure

    Molecular detection of

    Get PDF

    Successful Endoscopic Removal of a Lighter Swallowed 17 Months Before

    Get PDF
    The majority of ingested foreign bodies will pass safely through the gastrointestinal tract, but long and rigid foreign bodies are associated with an increased risk of gastrointestinal impaction, perforation and bleeding. However, large foreign bodies which have been swallowed can remain trapped in the stomach over a longer period of time without any significant symptoms. This case report describes the case of a 36-year-old man addicted to heroin who purposefully swallowed a lighter (double wrapped in cellophane) and presented with hematemesis and melena 17 months after the ingestion of the foreign body. The lighter was successfully removed via flexible endoscopy using a polypectomy snare. Swallowed long and rigid foreign bodies trapped in the stomach over a long period of time always represent a special clinical and endoscopic challenge. In cases where endoscopic removal fails, a laparoscopic surgical approach may be an alternative

    Measurement of the longitudinal and transverse cross-section in e^+e^- annihilation at sqrt(s)=35-44 GeV

    Get PDF
    An investigation of the polar angle distribution of charged hadrons is presented using data taken by the JADE experiment at the PETRA e^+e^- collider at centre-of-mass energies of 35 and 44 GeV. From fits to the polar angle distribution the longitudinal, sigma_L, and transverse, sigma_T, cross-section relative to the total hadronic are determined at an average energy scale of 36.6 GeV. The results are sigma_L/sigma_tot = 0.067 +/- 0.013, sigma_T/sigma_tot = 0.933 -/+ 0.013 where total errors are given and the results are exactly anti-correlated. Using the next-to-leading order QCD prediction for the longitudinal cross-section, the value alpha_S(36.6 GeV) = 0.150 +/- 0.025 of the strong coupling constant is obtained in agreement with the world average value of alpha_S evolved to an energy scale of 36.6 GeV.Comment: 12 pages, LaTeX2e, 5 .eps-files included, pennames.sty included, submitted to Phys. Lett.
    • …
    corecore