109 research outputs found

    Soil Disturbances from Horse/Mule Logging Operations Coupled with Machines in the Southern United States

    Get PDF
    Forest harvesting with animals is a labor-intensive operation. While mechanized logging is very efficient for large tracts of timber, it is often disruptive to the soil. Small logging operations using animals may be less environmentally disruptive. To better understand horse/mule logging performances for soil disturbance, five different horse/mule harvesting operations were investigated. About 75 percent of the soil was undisturbed and 22 percent of the remaining soil disturbance was judged to be slight. Only 3 percent of the soil examinations were classified as deeply disturbed and rutted – a condition considered to be prone to soil erosion. This study suggests that horse and mule logging has low soil disturbance in a partial cut of mixed pine/hardwood forests

    Utilization and Cost of Log Production from Animal Logging Operations

    Get PDF
    Forest harvesting with animals is a labor-intensive operation. It is expensive to use machines on smaller woodlots, which require frequent moves if mechanically logged. So, small logging systems using animals may be more cost effective. In this study, work sampling was used for five animal logging operations in Alabama to measure productive and non-productive time elements to determine utilization with respect to operators, functions (felling and processing of trees, skidding, loading, and forwarding of logs), animals, and machines. Cost of log production was calculated from the figures reported by owners and the crew members. Average utilization of crew was 58 percent, animals (horses and mules) were utilized only 22 percent and the machines were utilized from 5 to 74 percent of scheduled time. Average cost of log production per m3 was $11.28. There appears to be an opportunity to reduce cost of log production by coordinating functions, increasing scheduled work hours, utilization of machines and animals, and reducing labor cost

    Preface

    Get PDF

    Automatic analysis of DMA races using model checking and k-induction

    No full text
    Modern multicore processors, such as the Cell Broadband Engine, achieve high performance by equipping accelerator cores with small "scratch- pad" memories. The price for increased performance is higher programming complexity - the programmer must manually orchestrate data movement using direct memory access (DMA) operations. Programming using asynchronous DMA operations is error-prone, and DMA races can lead to nondeterministic bugs which are hard to reproduce and fix. We present a method for DMA race analysis in C programs. Our method works by automatically instrumenting a program with assertions modeling the semantics of a memory flow controller. The instrumented program can then be analyzed using state-of-the-art software model checkers. We show that bounded model checking is effective for detecting DMA races in buggy programs. To enable automatic verification of the correctness of instrumented programs, we present a new formulation of k-induction geared towards software, as a proof rule operating on loops. Our techniques are implemented as a tool, Scratch, which we apply to a large set of programs supplied with the IBM Cell SDK, in which we discover a previously unknown bug. Our experimental results indicate that our k-induction method performs extremely well on this problem class. To our knowledge, this marks both the first application of k-induction to software verification, and the first example of software model checking in the context of heterogeneous multicore processors. © Springer Science+Business Media, LLC 2011

    Conservation physiology and the quest for a ‘good’ Anthropocene

    Get PDF
    It has been proposed that we are now living in a new geological epoch known as the Anthropocene, which is specifically defined by the impacts that humans are having on the Earth’s biological diversity and geology. Although the proposal of this term was borne out of an acknowledgement of the negative changes we are imparting on the globe (e.g. climate change, pollution, coastal erosion, species extinctions), there has recently been action amongst a variety of disciplines aimed at achieving a ‘good Anthropocene’ that strives to balance societal needs and the preservation of the natural world. Here, we outline ways that the discipline of conservation physiology can help to delineate a hopeful, progressive and productive path for conservation in the Anthropocene and, specifically, achieve that vision. We focus on four primary ways that conservation physiology can contribute, as follows: (i) building a proactive approach to conservation; (ii) encouraging a pragmatic perspective; (iii) establishing an appreciation for environmental resilience; and (iv) informing and engaging the public and political arenas. As a collection of passionate individuals combining theory, technological advances, public engagement and a dedication to achieving conservation success, conservation physiologists are poised to make meaningful contributions to the productive, motivational and positive way forward that is necessary to curb and reverse negative human impact on the environment

    Conservation physiology and the quest for a ‘good’ Anthropocene

    Get PDF
    It has been proposed that we are now living in a new geological epoch known as the Anthropocene, which is specifically defined by the impacts that humans are having on the Earth’s biological diversity and geology. Although the proposal of this term was borne out of an acknowledgement of the negative changes we are imparting on the globe (e.g. climate change, pollution, coastal erosion, species extinctions), there has recently been action amongst a variety of disciplines aimed at achieving a ‘good Anthropocene’ that strives to balance societal needs and the preservation of the natural world. Here, we outline ways that the discipline of conservation physiology can help to delineate a hopeful, progressive and productive path for conservation in the Anthropocene and, specifically, achieve that vision. We focus on four primary ways that conservation physiology can contribute, as follows: (i) building a proactive approach to conservation; (ii) encouraging a pragmatic perspective; (iii) establishing an appreciation for environmental resilience; and (iv) informing and engaging the public and political arenas. As a collection of passionate individuals combining theory, technological advances, public engagement and a dedication to achieving conservation success, conservation physiologists are poised to make meaningful contributions to the productive, motivational and positive way forward that is necessary to curb and reverse negative human impact on the environment

    Elasmobranch responses to experimental warming, acidification, and oxygen loss—a meta-analysis

    Get PDF
    Despite the long evolutionary history of this group, the challenges brought by the Anthropocene have been inflicting an extensive pressure over sharks and their relatives. Overexploitation has been driving a worldwide decline in elasmobranch populations, and rapid environmental change, triggered by anthropogenic activities, may further test this group's resilience. In this context, we searched the literature for peer-reviewed studies featuring a sustained (>24 h) and controlled exposure of elasmobranch species to warming, acidification, and/or deoxygenation: three of the most pressing symptoms of change in the ocean. In a standardized comparative framework, we conducted an array of mixed-model meta-analyses (based on 368 control-treatment contrasts from 53 studies) to evaluate the effects of these factors and their combination as experimental treatments. We further compared these effects across different attributes (lineages, climates, lifestyles, reproductive modes, and life stages) and assessed the direction of impact over a comprehensive set of biological responses (survival, development, growth, aerobic metabolism, anaerobic metabolism, oxygen transport, feeding, behavior, acid-base status, thermal tolerance, hypoxia tolerance, and cell stress). Based on the present findings, warming appears as the most influential factor, with clear directional effects, namely decreasing development time and increasing aerobic metabolism, feeding, and thermal tolerance. While warming influence was pervasive across attributes, acidification effects appear to be more context-specific, with no perceivable directional trends across biological responses apart from the necessary to achieve acid-base balance. Meanwhile, despite its potential for steep impacts, deoxygenation has been the most neglected factor, with data paucity ultimately precluding sound conclusions. Likewise, the implementation of multi-factor treatments has been mostly restricted to the combination of warming and acidification, with effects approximately matching those of warming. Despite considerable progress over recent years, research regarding the impact of these drivers on elasmobranchs lags behind other taxa, with more research required to disentangle many of the observed effects. Given the current levels of extinction risk and the quick pace of global change, it is further crucial that we integrate the knowledge accumulated through different scientific approaches into a holistic perspective to better understand how this group may fare in a changing ocean

    Extended Joseph polynomials, quantized conformal blocks, and a q-Selberg type integral

    Get PDF
    We consider the tensor power V=(CN)⊗nV=(C^N)^{\otimes n} of the vector representation of glNgl_N and its weight decomposition V=⊕λ=(λ1,...,λN)V[λ]V=\oplus_{\lambda=(\lambda_1,...,\lambda_N)}V[\lambda]. For λ=(λ1≥...≥λN)\lambda = (\lambda_1 \geq ... \geq \lambda_N), the trivial bundle V[\lambda]\times \C^n\to\C^n has a subbundle of q-conformal blocks at level l, where l=λ1−λNl = \lambda_1-\lambda_N if λ1−λN>0\lambda_1-\lambda_N> 0 and l=1 if λ1−λN=0\lambda_1-\lambda_N=0. We construct a polynomial section Iλ(z1,...,zn,h)I_\lambda(z_1,...,z_n,h) of the subbundle. The section is the main object of the paper. We identify the section with the generating function Jλ(z1,...,zn,h)J_\lambda(z_1,...,z_n,h) of the extended Joseph polynomials of orbital varieties, defined in [DFZJ05,KZJ09]. For l=1, we show that the subbundle of q-conformal blocks has rank 1 and Iλ(z1,...,zn,h)I_\lambda(z_1,...,z_n,h) is flat with respect to the quantum Knizhnik-Zamolodchikov discrete connection. For N=2 and l=1, we represent our polynomial as a multidimensional q-hypergeometric integral and obtain a q-Selberg type identity, which says that the integral is an explicit polynomial

    Exposure to boat noise in the field yields minimal stress response in wild reef fish

    Get PDF
    Aquatic anthropogenic noise is on the rise, with growing concern about its impact on species that are sensitive to low-frequency sounds (e.g. most fish and invertebrates). We investigated whether the reef fish Halichoeres bivittatus living in both noisy and quiet areas had differing levels of baseline stress (measured as whole-body cortisol) and whether they would exhibit a physiological stress response when exposed to boat noise playbacks. While the playback experiments significantly increased cortisol levels in fish from our experiment compared to baseline levels, there were minimal pairwise differences across treatments and no difference in baseline stress for fish living in noisy vs. quiet areas. These results may be explained by low overall auditory sensitivity, habituation to a fairly noisy environment (due to biological sounds), or that boat noise simply may not represent an immediate threat to survival in this species. These findings contrast recent studies that have shown elevated stress responses in fishes when exposed to boat noise and highlights that inter-specific differences must be considered when evaluating potential impacts of anthropogenic noise on marine life
    • …
    corecore