2,612 research outputs found

    Higgs Boson Discovery and Properties

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    We outline issues examined and progress made by the Light Higgs Snowmass 1996 working group regarding discovering Higgs bosons and measuring their detailed properties. We focused primarily on what could be learned at LEP2, the Tevatron (after upgrade), the LHC, a next linear \epem collider and a \mupmum collider.Comment: 47 pages, full postscript file also available via anonymous ftp at ftp://ucdhep.ucdavis.edu/gunion/summary_snowmass96.ps To appear in ``Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High Energy Physics''. Minor revisions of references and wording have been made in a few place

    Optimal Forest Strategies for Addressing Tradeoffs and Uncertainty in Economic Development under Old-Growth Constraints

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    In Canada, governments have historically promoted economic development in rural regions by promoting exploitation of natural resources, particularly forests. Forest resources are an economic development driver in many of the more than 80% of native communities located in forest regions. But forests also provide aboriginal people with cultural and spiritual values, and non-timber forest amenities (e.g., biodiversity, wildlife harvests for meat and fur, etc.), that are incompatible with timber exploitation. Some cultural and other amenities can only be satisfied by maintaining a certain amount of timber in an old-growth state. In that case, resource constraints might be too onerous to satisfy development needs. We employ compromise programming and fuzzy programming to identify forest management strategies that best compromise between development and other objectives, applying our models to an aboriginal community in northern Alberta. In addition to describing how mathematical programming techniques can be applied to regional development and forest management, we conclude from the analysis that no management strategy is able to satisfy all of the technical, environmental and social/cultural constraints and, at the same time, offer aboriginal peoples forest-based economic development. Nonetheless, we demonstrate that extant forest management policies can be improved upon.forest-dependent aboriginal communities, boreal forest, compromise and fuzzy programming, sustainability and uncertainty, International Development, Resource /Energy Economics and Policy, R11, Q23, Q01, C61,

    Can Forest Management Strategies Sustain The Development Needs Of The Little Red River Cree First Nation?

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    In this study, we explore whether projected socio-economic needs of the Little Red River Cree Nation (LRRCN) can be met using the natural resources to which they have access. To answer this question, we employ a dynamic optimization model to assess the capacity of the available forest base to provide for anticipated future needs of the LRRCN. Results for alternative management strategies indicate that decision-makers face significant tradeoffs in deciding an appropriate management strategy for the forestlands they control.boreal forest, First Nations, forest management, sustainability

    CPT violation and B-meson oscillations

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    Recent evidence for anomalous CP violation in B-meson oscillations can be interpreted as resulting from CPT violation. This yields the first sensitivity to CPT violation in the B_s^0 system, with the relevant coefficient for CPT violation constrained at the level of parts in 10^{12}.Comment: 4 pages two-column REVTeX; Rapid Communications, Physical Review D, in pres

    Battle of the Predictive Wavefront Controls: Comparing Data and Model-Driven Predictive Control for High Contrast Imaging

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    Ground-based high contrast exoplanet imaging requires state-of-the-art adaptive optics (AO) systems in order to detect extremely faint planets next to their brighter host stars. For such extreme AO systems (with high actuator count deformable mirrors over a small field of view), the lag time of the correction (which can impact our system by the amount the wavefront has changed by the time the system is able to apply the correction) which can be anywhere from ~1-5 milliseconds, can cause wavefront errors on spatial scales that lead to speckles at small angular separations from the central star in the final science image. One avenue for correcting these aberrations is predictive control, wherein previous wavefront information is used to predict the future state of the wavefront in one-system-lag's time, and this predicted state is applied as a correction with a deformable mirror. Here, we consider two methods for predictive control: data-driven prediction using empirical orthogonal functions and the physically-motivated predictive Fourier control. The performance and robustness of these methods have not previously been compared side-by-side. In this paper, we compare these predictors by applying them as post-facto methods to simulated atmospheres and on-sky telemetry, to investigate the circumstances in which their performance differs, including testing them under different wind speeds, C_n^2 profiles, and time lags. We also discuss future plans for testing both algorithms on the Santa Cruz Extreme AO Laboratory (SEAL) testbed

    Influence of glutaraldehyde fixation of cells adherent to solid substrata on their detachment during exposure to shear stress

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    In order to determine the response of fixed and nonfixed cells adherent to a solid substratum to shear stress, human fibroblasts were allowed to adhere and spread on either hydrophilic glass or hydrophobic Fluoroethylene-propylene (FEP-Teflon) and fixed with glutaraldehyde. Then, the cells were exposed to an incrementally loaded shear stress in a parallel plate flow chamber up to shear stresses of about 500 dynes/cm2, followed by exposure to a liquid-air interface passage. The cellular detachment was compared with the one of nonfixed cells. In case of fixed cells, 50% of the adhering cells detached from FEP-Teflon at a shear stress of 350 dynes/cm2, whereas 50% of the adhering, nonfixed cells detached already at a shear stress of 20 dynes/cm2. No fixed cells detached from glass for shear stresses up to at least 500 dynes/cm2. More than 50% of the nonfixed cells were detached from glass at a shear stress of 350 dynes/cm2. Furthermore, the shape and morphology of fixed cells did not change during the incrementally loaded flow, in contrast to the ones of nonfixed cells, which clearly rounded up prior to detachment.</p
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