3,621 research outputs found

    Climate Change Impacts on Amazonian and Arctic Indigenous Tribes

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    This paper aims to touch upon the various climatic impacts on two differing indigenous tribes. The Amazon Rainforest and Arctic is home to a variety of native tribes. As climate change intensifies, these different groups are faced with differing impacts that has had a major impacts on their daily lives.https://digitalcommons.salve.edu/chp218/1002/thumbnail.jp

    Fagus sylvatica (European beech), ID: 1134

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    Location: Wakehurst, near labyrinthhttps://digitalcommons.salve.edu/bio140_arboretum/1006/thumbnail.jp

    Climate Change Impacts on Amazonian and Arctic Indigenous Tribes

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    This paper aims to touch upon the various climatic impacts on two differing indigenous tribes. The Amazon Rainforest and Arctic is home to a variety of native tribes. As climate change intensifies, these different groups are faced with differing impacts that has had a major impacts on their daily lives.https://digitalcommons.salve.edu/chp218/1001/thumbnail.jp

    Analysis of intrapulse chirp in CO2 oscillators

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    Pulsed single-frequency CO2 laser oscillators are often used as transmitters for coherent lidar applications. These oscillators suffer from intrapulse chirp, or dynamic frequency shifting. If excessive, such chirp can limit the signal-to-noise ratio of the lidar (by generating excess bandwidth), or limit the velocity resolution if the lidar is of the Doppler type. This paper describes a detailed numerical model that considers all known sources of intrapulse chirp. Some typical predictions of the model are shown, and simple design rules to minimize chirp are proposed

    Systematic Atmospheric Refreaction Errors of Baseline Type Radio Tracking Systems and Methods for their Correction

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    The theory of systematic atmospheric radio refraction errors affecting measurements of range and range differences (and associated time rate of change of these quantities) is developed. It is shown that the refraction errors, particularly in range difference measurements, can seriously affect the accuracy of baseline-type tracking systems. A method is derived by which the systematic portion of tL.ese errors can be removed by means of linear relationships involving the surface value of the radio refractive index; the correction process cievlsea can be used in real time if desired. Several test cases are examined where horizontally-varying profiles of the refractive index variation with height are used to calculate the errors, and the correction process based on surface refractive index values is found to be useful under these more general conditions. Approximately 98 percent of the total range or rangt difference error can be removed using this correction procedure. The problem of baseline optimization for deep-space tracking is examined briefly, and it is shown that a baseline length of about 4, 000 miles is optimal for targets more than about 6, 000 miles from the earth, and foi such a system residual atmospheric refraction errors would be only a fe\\ hundredths of a microradian, assuming the validity of ray optics and of the models of the atmosphere used in this paper

    Superior maturation and patency of primary brachiocephalic and transposed basilic vein arteriovenous fistulae in patients with diabetes

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    AbstractPurpose: Primary radiocephalic arteriovenous fistulas (RCAVFs) have classically been used for the initiation of dialysis. If a suitable forearm cephalic vein can be demonstrated, it is used to construct such a fistula. However, we have noted a tendency for RCAVF in patients with a history of diabetes mellitus (type I and type II) to remain patent but not mature to the point of cannulation. Therefore, the present study was undertaken. Methods: Fifty-eight consecutive patients with diabetes who required initial access for hemodialysis at an urban medical center and tertiary Veterans Medical Center underwent creation of an RCAVF (n = 10), brachiocephalic arteriovenous fistula (BCAVF; n = 22), or transposed basilic vein arteriovenous fistula (TBAVF; n = 26). The vein used was determined by physical examination with tourniquet compression. If neither forearm or upper-arm cephalic veins were 2 mm in diameter, a TBAVF was created after venography. Patency was determined by Kaplan-Meier estimate; differences between groups were assessed by Fisher's exact test. Results: The 70% rate of nonmaturation of RCAVFs was significantly greater than the 27% rate for BCAVFs and 0% for TBAVFs (p < 0.05). The 33% cumulative primary patency rate at 18 months for RCAVFs was significantly less than 78% for BCAVFs and 79% for TBAVFs (p < 0.001). Within and between groups, there were no significant differences in age, gender, aspirin use, history of congestive heart failure, erythropoietin use, hematocrit level, history of peripheral vascular disease, or mortality rate. Conclusions: In patients with renal failure and a history of diabetes, both primary BCAVFs and TBAVFs demonstrate significantly greater maturation and increased primary cumulative patency rates compared with RCAVFs; therefore, these autogenous conduits are considered to be optimal in this group of patients. Whether the discrepancy in lower-arm vein maturation is a result of a lack of compensatory increase in radial arterial flow or an intrinsic defect in the lower-arm cephalic vein is currently under investigation. (J Vasc Surg 1998;27:154-7.

    Religion/Spirituality as a Predictor of Attrition from a Culturally Informed Family Treatment for Schizophrenia that Targets Religious Coping

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    Symposium Title: The Integration of Religion/Spirituality into Culturally-Informed, Cognitive-Behavioral Mental Health Treatments Chair: Kayla K. Thayer, Ph.D., Nova Southeastern University Discussant: Stevan Lars Nielsen, Ph.D., Brigham Young Universit

    Toward a comprehensive global electric circuit model: Atmospheric conductivity and its variability in CESM1(WACCM) model simulations

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    As an important step in further modeling and understanding the global electric circuit, the Community Earth System Model (CESM1) has been extended to provide a calculation of conductivity in the troposphere and stratosphere. Conductivity depends on ion mobility and ion concentration, the latter being controlled by a number of ion production and loss processes. This leads to a complex dependency of conductivity on most importantly galactic cosmic ray flux, radon emissions from the Earth's surface, aerosol number concentrations, clouds, and temperature. To cover this variety in parameters for calculating and evaluating conductivity, an Earth system model is extremely useful. Here the extension of CESM1 to calculate conductivity is described, and the results are discussed with a focus on their spatial and temporal variabilities. The results are also compared to balloon and aircraft measurements, and good agreement is found for undisturbed conditions and during a solar proton event. The conductivity model implementation is a significant improvement to previous studies because of the high-quality, high-resolution model data input. Notably, the aerosol representation provided by off-line calculations of tropospheric and stratospheric aerosol using the Community Aerosol and Radiation Model for Atmospheres as part of CESM1(WACCM) (Whole Atmosphere Community Climate Model) provides a realistic computation of the impact of the background aerosol distribution for the first time. In addition to the novel high-resolution information on conductivity, it is found that an intra-annual cycle exists in the total global resistance, varying between 220 and 245 Ω. The model shows that this cycle is driven equally by seasonal aerosol and cloud variations
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