311 research outputs found

    Kinematic analysis of conically scanned environmental properties

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    A method for determining the velocity of features such as wind. The method preferably includes producing sensor signals and projecting the sensor signals sequentially along lines lying on the surface of a cone. The sensor signals may be in the form of lidar, radar or sonar for example. As the sensor signals are transmitted, the signals contact objects and are backscattered. The backscattered sensor signals are received to determine the location of objects as they pass through the transmission path. The speed and direction the object is moving may be calculated using the backscattered data. The data may be plotted in a two dimensional array with a scan angle on one axis and a scan time on the other axis. The prominent curves that appear in the plot may be analyzed to determine the speed and direction the object is traveling

    Sediment flux and fate in the Mississippi River Diversion at West Bay: observation study

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    Land-building sediment diversions, such as the Mississippi River Diversion at West Bay, can be used as important building blocks in the conservation and restoration of Mississippi Delta wetlands. Sediment deposition and retention patterns were studied in the West Bay diversion outfall area through analyses of sediment cores, hydrodynamics, and bathymetry. Cores and x-ray samples were collected at twenty stations in March 2004, August 2004, November 2005, and April 2006. Cores were analyzed for grain-size distributions and 7Be activities, in order to examine patterns of recent sediment deposition. In comparing ratios of total 7Be inventory to atmospheric 7Be deposition rates, it was estimated that 10%, 60%, and 30% of the cores experienced net accretion, net erosion, and no deposition, respectively. Turbidity and velocity data collected during instrument deployments along with historical Mississippi River flows and sediment loads were used to estimate an average sediment influx of 2.9 x 106 tons/year (2.6 x 109 kg/year). A sediment trapping efficiency of 25 - 50% was estimated by comparing sediment influx with 7Be penetration depths observed. This estimation could not be verified by bathymetric surveys conducted in April 2006 and compared to pre-construction surveys from 2003. Volumetric change calculations estimated a loss of over 4.16 x 106 yd3 (3.18 x 106 m3) of sediment from the bay bottom. It is speculated that these losses were caused by Hurricane Katrina which made landfall on August 29, 2005 approximately 15 nautical miles (28 km) from the study area. Potential deltaic growth rates of between 51 ac/year (21 ha/year) and 143 ac/year (59 ha/year) were estimated for the diversion by comparing delta growth parameters estimated in this study with the Wax Lake Delta. These estimates suggest that delta-building processes at West Bay may continue following a typical subdelta growth curve of 100 - 150 years, meaning peak development of deltaic wetlands could be decades away. Therefore, future planning for diversions should consider coastal process which could potentially counter environmental benefits and engineering strategies should place as much focus on receiving area configuration and trapping efficiency as sediment delivery in order to maximize sediment retention

    Critical discourse analysis and rhetoric and composition

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    pre-printOver the past two decades, critical discourse analysis has emerged as a major new multidisciplinary approach to the study of texts and contexts in the public sphere. Developed in Europe, CDA has lately become increasingly popular in North America, where it is proving especially congenial to new directions in rhetoric and composition. This essay surveys much of this recent literature, noting how rhet/comp has incorporated CDA methodology in a variety of studies of inequality, ethics, higher education, critical pedagogy, news media, and institutional practices. CDA uses rigorous, empirical methods that are sensitive to both context and theory, making it ideal for the demands of a range of projects being developed in our field

    The Q^2-Dependence of Nuclear Transparency for Exclusive ρ0\rho^0 Production

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    Exclusive coherent and incoherent electroproduction of the ρ0\rho^0 meson from 1^1H and 14^{14}N targets has been studied at the HERMES experiment as a function of coherence length (lcl_c), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (Q2-Q^2). The ratio of 14^{14}N to 1^1H cross sections per nucleon, known as nuclear transparency, was found to increase (decrease) with increasing coherence length for coherent (incoherent) ρ0\rho^0 electroproduction. For fixed coherence length, a rise of nuclear transparency with Q2Q^2 is observed for both coherent and incoherent ρ0\rho^0 production, which is in agreement with theoretical calculations of color transparency.Comment: 5 pages, 4 figure

    Flavor decomposition of the sea quark helicity distributions in the nucleon from semi-inclusive deep-inelastic scattering

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    Double-spin asymmetries of semi-inclusive cross sections for the production of identified pions and kaons have been measured in deep-inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with re-analyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.Comment: 5 pages, 3 figure

    Changing patterns of eastern Mediterranean shellfish exploitation in the Late Glacial and Early Holocene: Oxygen isotope evidence from gastropod in Epipaleolithic to Neolithic human occupation layers at the Haua Fteah cave, Libya

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    The seasonal pattern of shellfish foraging at the archaeological site of Haua Fteah in the Gebel Akhdar, Libya was investigated from the Epipaleolithic to the Neolithic via oxygen isotope (d18O) analyses of the topshell Phorcus (Osilinus) turbinatus. To validate this species as faithful year-round palaeoenvironmental recorder, the intra-annual variability of d18O in modern shells and sea water was analysed and compared with measured sea surface temperature (SST). The shells were found to be good candidates for seasonal shellfish forging studies as they preserve nearly the complete annual SST cycle in their shell d18O with minimal slowing or stoppage of growth. During the terminal Pleistocene Early Epipaleolithic (locally known as the Oranian, with modeled dates of 17.2-12.5 ka at 2sigma probability, Douka et al., 2014), analysis of archaeological specimens indicates that shellfish were foraged year-round. This complements other evidence from the archaeological record that shows that the cave was more intensively occupied in this period than before or afterwards. This finding is significant as the period of the Oranian was the coldest and driest phase of the last glacial cycle in the Gebel Akhdar, adding weight to the theory that the Gebel Akhdar may have served as a refugium for humans in North Africa during times of global climatic extremes. Mollusc exploitation in the Latest Pleistocene and Early Holocene, during the Late Epipaleolithic (locally known as the Capsian, c. 12.7 to 9 ka) and the Neolithic (c. 8.5 to 5.4 ka), occurred predominantly during winter. Other evidence from these archaeological phases shows that hunting activities occurred during the warmer months. Therefore, the timing of Holocene shellfish exploitation in the Gebel Akhdar may have been influenced by the seasonal availability of other resources at these times and possibly shellfish were used as a dietary supplement when other foods were less abundant

    Effects of bark beetle outbreaks on forest landscape pattern in the southern rocky mountains, U.S.A.

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    Since the late 1990s, extensive outbreaks of native bark beetles (Curculionidae: Scolytinae) have affected coniferous forests throughout Europe and North America, driving changes in carbon storage, wildlife habitat, nutrient cycling, and water resource provisioning. Remote sensing is a cru-cial tool for quantifying the effects of these disturbances across broad landscapes. In particular, Landsat time series (LTS) are increasingly used to characterize outbreak dynamics, including the presence and severity of bark beetle-caused tree mortality, though broad-scale LTS-based maps are rarely informed by detailed field validation. Here we used spatial and temporal information from LTS products, in combination with extensive field data and Random Forest (RF) models, to develop 30-m maps of the presence (i.e., any occurrence) and severity (i.e., cumulative percent basal area mortality) of beetle-caused tree mortality 1997–2019 in subalpine forests throughout the Southern Rocky Mountains, USA. Using resultant maps, we also quantified spatial patterns of cumulative tree mortality throughout the region, an important yet poorly understood concept in beetle-affected forests. RF models using LTS products to predict presence and severity performed well, with 80.3% correctly classified (Kappa = 0.61) and R2 = 0.68 (RMSE = 17.3), respectively. We found that ≥10,256 km2 of subalpine forest area (39.5% of the study area) was affected by bark beetles and 19.3% of the study area experienced ≥70% tree mortality over the twenty-three year period. Variograms indi-cated that severity was autocorrelated at scales \u3c 250 km. Interestingly, cumulative patch-size dis-tributions showed that areas with a near-total loss of the overstory canopy (i.e., ≥90% mortality) were relatively small (\u3c0.24 km2) and isolated throughout the study area. Our findings help to in-form an understanding of the variable effects of bark beetle outbreaks across complex forested regions and provide insight into patterns of disturbance legacies, landscape connectivity, and susceptibility to future disturbance

    A Multi-Proxy Assessment of the Impact of Environmental Instability on Late Holocene (4500-3800 BP) Native American Villages of the Georgia Coast

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    Circular shell rings along the South Atlantic Coast of North America are the remnants of some of the earliest villages that emerged during the Late Archaic (5000-3000 BP). Many of these villages, however, were abandoned during the Terminal Late Archaic (ca 3800-3000 BP). We combine Bayesian chronological modeling with mollusk shell geochemistry and oyster paleobiology to understand the nature and timing of environmental change associated with the emergence and abandonment of circular shell ring villages on Sapelo Island, Georgia. Our Bayesian models indicate that Native Americans occupied the three Sapelo shell rings at varying times with some generational overlap. By the end of the complex\u27s occupation, only Ring III was occupied before abandonment ca. 3845 BP. Ring III also consists of statistically smaller oysters harvested from less saline estuaries compared to earlier occupations. Integrating shell biochemical and paleobiological data with recent tree ring analyses shows a clear pattern of environmental fluctuations throughout the period in which the rings were occupied. We argue that as the environment became unstable around 4300 BP, aggregation at villages provided a way to effectively manage fisheries that are highly sensitive to environmental change. However, with the eventual collapse of oyster fisheries and subsequent rebound in environmental conditions ca. post-3800 BP, people dispersed from shell rings, and shifted to non-marine subsistence economies and other types of settlements. This study provides the most comprehensive evidence for correlations between large-scale environmental change and societal transformations on the Georgia coast during the Late Archaic period

    Gene expression patterns in the hippocampus and amygdala of endogenous depression and chronic stress models

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    The etiology of depression is still poorly understood, but two major causative hypotheses have been put forth: the monoamine deficiency and the stress hypotheses of depression. We evaluate these hypotheses using animal models of endogenous depression and chronic stress. The endogenously depressed rat and its control strain were developed by bidirectional selective breeding from the Wistar–Kyoto (WKY) rat, an accepted model of major depressive disorder (MDD). The WKY More Immobile (WMI) substrain shows high immobility/despair-like behavior in the forced swim test (FST), while the control substrain, WKY Less Immobile (WLI), shows no depressive behavior in the FST. Chronic stress responses were investigated by using Brown Norway, Fischer 344, Lewis and WKY, genetically and behaviorally distinct strains of rats. Animals were either not stressed (NS) or exposed to chronic restraint stress (CRS). Genome-wide microarray analyses identified differentially expressed genes in hippocampi and amygdalae of the endogenous depression and the chronic stress models. No significant difference was observed in the expression of monoaminergic transmission-related genes in either model. Furthermore, very few genes showed overlapping changes in the WMI vs WLI and CRS vs NS comparisons, strongly suggesting divergence between endogenous depressive behavior- and chronic stress-related molecular mechanisms. Taken together, these results posit that although chronic stress may induce depressive behavior, its molecular underpinnings differ from those of endogenous depression in animals and possibly in humans, suggesting the need for different treatments. The identification of novel endogenous depression-related and chronic stress response genes suggests that unexplored molecular mechanisms could be targeted for the development of novel therapeutic agents

    Non-medical prescribing versus medical prescribing for acute and chronic disease management in primary and secondary care.

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    The aim of this Cochrane review was to find out if prescribing by health professionals other than doctors delivers comparable outcomes to prescribing by doctors. Cochrane researchers collected and analysed all relevant studies to answer this question and found 46 studies. Key messages With appropriate training and support, nurses and pharmacists are able to prescribe medicines as part of managing a range of conditions to achieve comparable health management outcomes to doctors. The majority of studies focus on chronic disease management in higher-income counties where there is generally a moderate-certainty of evidence supporting similar outcomes for the markers of disease in high blood pressure, diabetes, and high cholesterol. Further high-quality studies are needed in poorer countries and to better quantify differences in prescribing outcomes for adverse events, and to determine health economic outcomes. Further studies could also focus more specifically on the prescribing component of care. What was studied in the review? A number of countries allow health professionals other than doctors to prescribe medicines. This shift in roles is thought to provide improved and timely access to medicines for consumers where there are shortages of doctors or the health system is facing pressures in coping with the burden of disease. In addition, this task shift has been supported by a number of governments as a way to more appropriately use the skills of health professionals, such as nurses and pharmacists, in the care of patients. We compared the outcomes of any healthcare workers who were prescribing with a high degree of autonomy with medical prescribers in the hospital or community setting in low-, middle- and high-income countries. What are the main results of the review? This review found 45 studies where nurses and pharmacists with high levels of prescribing autonomy were compared with usual care medical prescribers. A further study compared nurse prescribing with guideline support with usual nurse prescribing care. No studies were found with other health professionals or lay prescribers. Four nurse prescribing studies were undertaken in the low- and middle-income settings of Colombia, South Africa, Uganda, and Thailand. The remainder of studies were undertaken in high-income Western countries. Forty-two studies were based in a community setting, two studies were located in hospitals, one study in the workplace, and one study in an aged care facility. Prescribing was but one part of many health-related interventions, particularly in the management of chronic disease. The review found that the outcomes for non-medical prescribers were comparable to medical prescribers for: high blood pressure (moderate-certainty of evidence); diabetes control (high-certainty of evidence); high cholesterol (moderate-certainty of evidence); adverse events (low-certainty of evidence); patients adhering to their medication regimeans (moderate-certainty of evidence); patient satisfaction with care (moderate-certainty of evidence); and health-related quality of life (moderate-certainty of evidence). Pharmacists and nurses with varying levels of undergraduate, postgraduate, and specific on-the-job training related to the disease or condition were able to deliver comparable prescribing outcomes to doctors. Non-medical prescribers frequently had medical support available to facilitate a collaborative practice model
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