132 research outputs found

    Zoonosis emergence linked to agricultural intensification and environmental change

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    A systematic review was conducted by a multidisciplinary team to analyze qualitatively best available scientific evidence on the effect of agricultural intensification and environmental changes on the risk of zoonoses for which there are epidemiological interactions between wildlife and livestock. The study found several examples in which agricultural intensification and/or environmental change were associated with an increased risk of zoonotic disease emergence, driven by the impact of an expanding human population and changing human behavior on the environment. We conclude that the rate of future zoonotic disease emergence or reemergence will be closely linked to the evolution of the agriculture–environment nexus. However, available research inadequately addresses the complexity and interrelatedness of environmental, biological, economic, and social dimensions of zoonotic pathogen emergence, which significantly limits our ability to predict, prevent, and respond to zoonotic disease emergence

    Severe Acute Respiratory Syndrome Coronavirus 2 Reinfection: A Case Series From a 12-Month Longitudinal Occupational Cohort

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    Findings are described in 7 patients with severe acute respiratory syndrome coronavirus 2 reinfection from the National Basketball Association 2020-2021 occupational testing cohort, including clinical details, antibody test results, genomic sequencing, and longitudinal reverse-transcription polymerase chain reaction results. Reinfections were infrequent and varied in clinical presentation, viral dynamics, and immune response

    A high-resolution infrared spectroscopic investigation of the halogen atom-HCN entrance channel complexes solvated in superfluid helium droplets

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    Rotationally resolved infrared spectra are reported for the X-HCN (X = Cl, Br, I) binary complexes solvated in helium nanodroplets. These results are directly compared with that obtained previously for the corresponding X-HF complexes [J. M. Merritt, J. K\"upper, and R. E. Miller, PCCP, 7, 67 (2005)]. For bromine and iodine atoms complexed with HCN, two linear structures are observed and assigned to the 2Σ1/2^{2}\Sigma_{1/2} and 2Π3/2^{2}\Pi_{3/2} ground electronic states of the nitrogen and hydrogen bound geometries, respectively. Experiments for HCN + chlorine atoms give rise to only a single band which is attributed to the nitrogen bound isomer. That the hydrogen bound isomer is not stabilized is rationalized in terms of a lowering of the isomerization barrier by spin-orbit coupling. Theoretical calculations with and without spin-orbit coupling have also been performed and are compared with our experimental results. The possibility of stabilizing high-energy structures containing multiple radicals is discussed, motivated by preliminary spectroscopic evidence for the di-radical Br-HCCCN-Br complex. Spectra for the corresponding molecular halogen HCN-X2_{2} complexes are also presented.Comment: 20 pages, 15 figures, 6 tables, RevTe

    Success-First Decision Theories

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    The standard formulation of Newcomb's problem compares evidential and causal conceptions of expected utility, with those maximizing evidential expected utility tending to end up far richer. Thus, in a world in which agents face Newcomb problems, the evidential decision theorist might ask the causal decision theorist: "if you're so smart, why ain’cha rich?” Ultimately, however, the expected riches of evidential decision theorists in Newcomb problems do not vindicate their theory, because their success does not generalize. Consider a theory that allows the agents who employ it to end up rich in worlds containing Newcomb problems and continues to outperform in other cases. This type of theory, which I call a “success-first” decision theory, is motivated by the desire to draw a tighter connection between rationality and success, rather than to support any particular account of expected utility. The primary aim of this paper is to provide a comprehensive justification of success-first decision theories as accounts of rational decision. I locate this justification in an experimental approach to decision theory supported by the aims of methodological naturalism

    Transits across a Cyclopentadienyl: Organic and Organometallic Haptotropic Shifts

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    references cited therein. (13) Electron acceptors which are also conjugated with the alkene r system will polarize the HOMO in the same directions as, but to a smaller extent than, Inductive acceptors.8 (14) There has been a suggestion that Me is an acceptor relative to H when attached to an sp3 carbon [C. A. Grob, Angew. Chem. lnt. Ed. Engl., 15, 569 (1976), and references cited therein]. The product ratio discussed here reflect this, but the IP changes do not. A subtle role of solvent may be involved. (15) J. Bastideand J. P. Maier, Chem. Phys., 12, 144 (1976 Li+, CUR+), the e component of which greatly stabilizes the most symmetrical q5 coordination. The lower the energy of the e acceptor set and the better the overlap with its Cp counterpart, the more are q2 and q5 stabilized relative to 7'. In the case of XH3+ (X = C, Si, Ge, Sn) an e acceptor orbital moves to lower energy as one proceeds down the group, and this is responsible for the decreasing barrier for sigmatropic shifts in CpXH3. The XH2 case, which yields a number of interesting collapse structures, is analyzed in detail for X, a main group center. Contrast the interaction of a cyclopentadienide anion and a proton with the interaction of the same anion and a Mn(CO)3+ fragment. Both result in stable molecules: cyclopentadiene (1) and V~-C~M~( C O )~ (2). But what a difference in the equilibrium geometries of these end products of the interaction! If we focus our attention on the cyclopentadienide site where the interacting partner settles down, then the proton chooses a position near to one carbon of the ring, but the Mn(C0)3+ fragment sits directly over the center of the ring. The ramifications of this differential are the concern of this paper. We will examine the interaction of a cyclopentadienide (CsHs-, Cp) ion with an interacting group X, X = H+, CH3+, SiR3+, Mn(C0)3+, CH22f, CH2. The result will consist of some conclusions concerning the equilibrium geometry of CpX as well as the relative energetics of the various haptotropic reactions of this Consider the passage of the interacting group X across the face of a Cp molecule, moving as indicated in 3 in a plane parallel to the Cp ring. Let the distance d be a separation at which there is sizable interaction between the frontier orbitals of X and the Cp a system. For a surface so constrained the asymmetric unit that need be calculated consists of the shaded area in 4, and two of the three boundaries of that area are contained in a transit along a line shown in projection in 5. Mirror symmetry is maintained at all points. The numbers nq shown along that line are convenient labels invoking a connection to the inorganic 7" notation* for denoting an approximate coordination geometry. In order to avoid confusion with structure numbers and ring carbon numbers, we have labeled the various sites along the transit line as 17, 217, . . . , 57. The site labeled 17, or some geometry near it, corresponds to or simple u interaction, such as we have in the collapse product cyclopentadiene. The 7IS site 57 is where one better come up with maximum stabilization for X = Mn(C0)3+. The site labeled 27 positions X over the center of a bond, and obviously will describe the important transition state region for a sigmatropic shift of a system like cyclopentadiene. 37 and 47 are not so easily defined. Experimentally, slippage of Cp rings from q5 coordination is often observed and q3 or q4 coordination may or may not be invoked. Somewhat arbitrarily we define 317 at the intersection of the transit line with the line joining C-2 and C-5 projected on the transit plane. The tetrahapto coordination site is most ambiguous (it could be near 37 or near 57), and SO we will not label any position as such. The analysis will consist of an inspection of interaction diagrams for the orbitals of Cp and X, as the ligand X and its position along the transit are varied. The qualitative arguments based on symmetry and overlap are supported by extended Huckel calculations whose details are given in the Appendix. The reader should be aware that this is an approximate metho

    Nonequivalent lethal equivalents : Models and inbreeding metrics for unbiased estimation of inbreeding load

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    We thank Peter Arcese, A. Bradley Duthie, Richard Frankham, Christine Grossen, Catherine Grueber, Marty Kardos, and three anonymous reviewers for helpful comments and discussion on earlier versions of this manuscript. We thank Cate Lessels and Peter Boag from whose 1987 paper in The Auk we copied the idea for the title of this paper. Our work was supported by a Swiss National Science Foundation grant (31003A-116794) to LFK, the Forschungskredit of the University of Zurich (FK-15-104) and a Swiss National Science Foundation grant (P2ZHP3_168447) to PN, and JMR was supported by a European Research Council grant.Peer reviewedPublisher PD

    Histone Deacetylase Activity Modulates Alternative Splicing

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    There is increasing evidence to suggest that splicing decisions are largely made when the nascent RNA is still associated with chromatin. Here we demonstrate that activity of histone deacetylases (HDACs) influences splice site selection. Using splicing-sensitive microarrays, we identified ∼700 genes whose splicing was altered after HDAC inhibition. We provided evidence that HDAC inhibition induced histone H4 acetylation and increased RNA Polymerase II (Pol II) processivity along an alternatively spliced element. In addition, HDAC inhibition reduced co-transcriptional association of the splicing regulator SRp40 with the target fibronectin exon. We further showed that the depletion of HDAC1 had similar effect on fibronectin alternative splicing as global HDAC inhibition. Importantly, this effect was reversed upon expression of mouse HDAC1 but not a catalytically inactive mutant. These results provide a molecular insight into a complex modulation of splicing by HDACs and chromatin modifications

    Nothing Lasts Forever: Environmental Discourses on the Collapse of Past Societies

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    The study of the collapse of past societies raises many questions for the theory and practice of archaeology. Interest in collapse extends as well into the natural sciences and environmental and sustainability policy. Despite a range of approaches to collapse, the predominant paradigm is environmental collapse, which I argue obscures recognition of the dynamic role of social processes that lie at the heart of human communities. These environmental discourses, together with confusion over terminology and the concepts of collapse, have created widespread aporia about collapse and resulted in the creation of mixed messages about complex historical and social processes

    Initial sequencing and analysis of the human genome

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    The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62798/1/409860a0.pd
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