3,740 research outputs found

    Ecological characterization of the Florida springs coast: Pithlachascotee to Waccasassa Rivers

    Get PDF
    This report covers the upper coast of west-central Florida. This region includes the drainage basins and nearshore waters of the west coast of Florida between, but not including, the Anclote River basin and the Suwannee River basin. The name Springs Coast wash chosen because this area contains a multitude of springs, both named and too small or inaccessible to have been names. Much of the area is karstic limestone. Most recognizable among the springs are the famous Crystal river, Weeki Wachee, and Homosassa. This territory includes large expanses of marsh and wetland and, along its shores, the southern end of the largest area of seagrass beds in the state -- the Florida Big Bend Seagrass Beds preserve. It also possesses numerous spring-fed rivers and streams along the coast, whose constant discharges provide unique, relatively stable estuarine environments. This document is a summary of the available information on the Springs Coast area of Florida, for use by planners, developers, regulatory authorities, and other interested parties. An understanding of the factors affecting their plans and the possibly unexpected impacts of their actions on others will, it is hoped, promote intelligent development in areas capable of supporting it. We have tried to provide a clear, coherent picture of what is currently known about how the physical, chemical, and biological factors of the environment interact. (343 pp.

    Can gravitational infall energy lead to the observed velocity dispersion in DLAs?

    Full text link
    The median observed velocity width v_90 of low-ionization species in damped Ly-alpha systems is close to 90 km/s, with approximately 10% of all systems showing v_90 > 210 km/s at z=3. We show that a relative shortage of such high-velocity neutral gas absorbers in state-of-the-art galaxy formation models is a fundamental problem, present both in grid-based and particle-based numerical simulations. Using a series of numerical simulations of varying resolution and box size to cover a wide range of halo masses, we demonstrate that energy from gravitational infall alone is insufficient to produce the velocity dispersion observed in damped Ly-alpha systems, nor does this dispersion arise from an implementation of star formation and feedback in our highest resolution (~ 45 pc) models, if we do not put any galactic winds into our models by hand. We argue that these numerical experiments highlight the need to separate dynamics of different components of the multiphase interstellar medium at z=3.Comment: 12 Pages, 9 Figures, accepted to ApJ, printing in colour recommende

    Parameterized Littlewood-Paley operators with variable kernels on Hardy spaces and weak Hardy spaces

    Get PDF
    In this paper, by using the atomic decomposition theory of Hardy space and weak Hardy space, we discuss the boundedness of parameterized Littlewood-Paley operator with variable kernel on these spaces.Comment: 15 pages. arXiv admin note: text overlap with arXiv:1711.0961

    Magnetic White Dwarfs from the SDSS II. The Second and Third Data Releases

    Full text link
    Fifty-two magnetic white dwarfs have been identified in spectroscopic observations from the Sloan Digital Sky Survey (SDSS) obtained between mid-2002 and the end of 2004, including Data Releases 2 and 3. Though not as numerous nor as diverse as the discoveries from the first Data Release, the collection exhibits polar field strengths ranging from 1.5MG to ~1000MG, and includes two new unusual atomic DQA examples, a molecular DQ, and five stars that show hydrogen in fields above 500MG. The highest-field example, SDSSJ2346+3853, may be the most strongly magnetic white dwarf yet discovered. Analysis of the photometric data indicates that the magnetic sample spans the same temperature range as for nonmagnetic white dwarfs from the SDSS, and support is found for previous claims that magnetic white dwarfs tend to have larger masses than their nonmagnetic counterparts. A glaring exception to this trend is the apparently low-gravity object SDSSJ0933+1022, which may have a history involving a close binary companion.Comment: 20 pages, 4 figures Accepted for publication in the Astronomical Journa

    Negative emotional stimuli reduce contextual cueing but not response times in inefficient search

    Get PDF
    In visual search, previous work has shown that negative stimuli narrow the focus of attention and speed reaction times (RTs). This paper investigates these two effects by first asking whether negative emotional stimuli narrow the focus of attention to reduce the learning of a display context in a contextual cueing task and, second, whether exposure to negative stimuli also reduces RTs in inefficient search tasks. In Experiment 1, participants viewed either negative or neutral images (faces or scenes) prior to a contextual cueing task. In a typical contextual cueing experiment, RTs are reduced if displays are repeated across the experiment compared with novel displays that are not repeated. The results showed that a smaller contextual cueing effect was obtained after participants viewed negative stimuli than when they viewed neutral stimuli. However, in contrast to previous work, overall search RTs were not faster after viewing negative stimuli (Experiments 2 to 4). The findings are discussed in terms of the impact of emotional content on visual processing and the ability to use scene context to help facilitate search

    From Isotopes to TK Interviews: Towards Interdisciplinary Research in Fort Resolution and the Slave River Delta, Northwest Territories

    Get PDF
    Evolving research in Fort Resolution and the Slave River Delta, Northwest Territories, aims to improve understanding of how the natural ecosystem functions and responds to various environmental stressors, as well as to enhance the stewardship of natural resources and the capacity of local residents to respond to change. We seek to integrate approaches that span the natural and social sciences and traditional knowledge understandings of change, employing a research design developed in response to the concerns of a northern community. In doing so, we have strived for a research process that is collaborative, interdisciplinary, policy-oriented, and reflective of northern priorities. These elements characterize the new northern research paradigm increasingly promoted by various federal funding agencies, northern partners, and communities. They represent a holistic perspective in the pursuit of solutions to address complex environmental and socioeconomic concerns about impacts of climate change and resource development on northern societies. However, efforts to fulfill the objectives of this research paradigm are associated with a host of on-the-ground challenges. These challenges include (but are not restricted to) developing effective community partnerships and collaboration and documenting change through interdisciplinary approaches. Here we provide an overview of the components that comprise our interdisciplinary research program and offer an accounting of our formative experiences in confronting these challenges

    Minimally Invasive Mitral Valve Surgery II: Surgical Technique and Postoperative Management.

    Get PDF
    Techniques for minimally invasive mitral valve repair and replacement continue to evolve. This expert opinion, the second of a 3-part series, outlines current best practices for nonrobotic, minimally invasive mitral valve procedures, and for postoperative care after minimally invasive mitral valve surgery

    Spectroscopic Sensitivity

    Get PDF
    We describe the overall performance of the STIS CCD after HST Servicing Mission #4 and the associated updates to calibration reference files. Most aspects of CCD performance are found to be fairly consistent with extrapolations of the trends seen prior to the failure of STIS in August 2004. The CCD gain value for the CCDGAIN = 4 setting has been redetermined using net count ratios of standard star spectra taken in the CCDGAIN = 1 and CCDGAIN = 4 settings, resulting in a gain value of 4.016 ± 0.003 e − /DN, which is 0.5% lower than the value used for the calibration of archival STIS CCD data taken before August 2004. Finally, we identify two independent indications of a temperature dependence of the Charge Transfer Efficiency (CTE). However, more calibration data are needed to verify the significance of this effect and, if verified, to calibrate it as a function of CCD housing temperature (as a proxy for CCD chip temperature). This option will be reassessed later during the Cycle 17 calibration program.
    corecore