2,110 research outputs found

    Using Wireless Sensor Networks for Precision Irrigation Scheduling

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    An Assessment of Hospital-Sponsored Health Care for the Uninsured in Polk County/Des Moines, Iowa

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    Health care providers in Polk County are faced with increasing numbers of low-income, uninsured patients who do not have the resources to pay for their health care out of pocket. At the same time, state and local funding sources are limited, and are insufficient to ensure that these individuals have access to the health services that they require. Community leaders are extremely interested in developing information to understand the magnitude of the uninsured problem in Polk County and to identify health care delivery strategies to better serve this population. A Blue Ribbon Steering Committee was convened in October 2004 to examine how hospital-sponsored health care is currently delivered to the uninsured in Polk County. The Committee\u27s goal was to create a participatory process to plan an effective and sustaining model to deliver core safety net services to the County\u27s uninsured. To assist them with these tasks, researchers from The George Washington University\u27s School of Public Health and Health Services, Department of Health Policy, were retained to conduct an assessment of hospital-sponsored health care services delivered to Polk County\u27s uninsured. This assessment is designed to highlight key issues affecting access to care for uninsured and underinsured residents, and to present potential policy options for restructuring hospital-based services in the county

    Scaling analysis of a model Hamiltonian for Ce3+^{3+} impurity in a cubic metal

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    We introduce various exchange interactions in a model Hamiltonian for Ce3+^{3+} ions in cubic symmetry with three configurations (f0f^0,f1f^1,f2f^2). With the impurity pseudo spin SI=1/2S_I=1/2, our Hamiltonian includes: (i) One-channel Sc=1/2S_c=1/2 Anderson model; (ii) Two-channel Sc=1/2S_c=1/2 Anderson model; (iii) An unforseen one-channel Sc=3/2S_c=3/2 Anderson model with a non-trivial fixed point; (iv) Mixing exchange interaction between the Γ6,7\Gamma_{6,7} and the Γ8\Gamma_8 conduction electron partial wave states; (v) Multiple conduction electron partial wave states. Using the third-order scaling (perturbative renormalization group) analysis, we study stability of various fixed points relevant to various exchange interactions for Ce3+^{3+} ions in cubic symmetry.Comment: 68 pages. 4 figures are available upon request from [email protected] (revised

    Variants in the human potassium channel gene (KCNN3) are associated with migraine in a high risk genetic isolate

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    The calcium-activated potassium ion channel gene (KCNN3) is located in the vicinity of the familial hemiplegic migraine type 2 locus on chromosome 1q21.3. This gene is expressed in the central nervous system and plays a role in neural excitability. Previous association studies have provided some, although not conclusive, evidence for involvement of this gene in migraine susceptibility. To elucidate KCNN3 involvement in migraine, we performed gene-wide SNP genotyping in a high-risk genetic isolate from Norfolk Island, a population descended from a small number of eighteenth century Isle of Man ‘Bounty Mutineer’ and Tahitian founders. Phenotype information was available for 377 individuals who are related through the single, well-defined Norfolk pedigree (96 were affected: 64 MA, 32 MO). A total of 85 SNPs spanning the KCNN3 gene were genotyped in a sub-sample of 285 related individuals (76 affected), all core members of the extensive Norfolk Island ‘Bounty Mutineer’ genealogy. All genotyping was performed using the Illumina BeadArray platform. The analysis was performed using the statistical program SOLAR v4.0.6 assuming an additive model of allelic effect adjusted for the effects of age and sex. Haplotype analysis was undertaken using the program HAPLOVIEW v4.0. A total of four intronic SNPs in the KCNN3 gene displayed significant association (P < 0.05) with migraine. Two SNPs, rs73532286 and rs6426929, separated by approximately 0.1 kb, displayed complete LD (r2 = 1.00, D′ = 1.00, D′ 95% CI = 0.96–1.00). In all cases, the minor allele led to a decrease in migraine risk (beta coefficient = 0.286–0.315), suggesting that common gene variants confer an increased risk of migraine in the Norfolk pedigree. This effect may be explained by founder effect in this genetic isolate. This study provides evidence for association of variants in the KCNN3 ion channel gene with migraine susceptibility in the Norfolk genetic isolate with the rarer allelic variants conferring a possible protective role. This the first comprehensive analysis of this potential candidate gene in migraine and also the first study that has utilised the unique Norfolk Island large pedigree isolate to implicate a specific migraine gene. Studies of additional variants in KCNN3 in the Norfolk pedigree are now required (e.g. polyglutamine variants) and further analyses in other population data sets are required to clarify the association of the KCNN3 gene and migraine risk in the general outbred population

    Crystal Field Triplets: A New Route to Non-Fermi Liquid Physics

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    A model for crystal field triplet ground states on rare earth or actinide ions with dipolar and quadrupolar couplings to conduction electrons is studied for the first time with renormalization group methods. The quadrupolar coupling leads to a new nontrivial, non-Fermi liquid fixed point, which survives in an intermediate valence Anderson model. The calculated magnetic susceptibility displays one parameter scaling, going as TαT^{-\alpha} (α0.4\alpha \approx 0.4) at intermediate temperatures, reminiscent of the non-Fermi liquid alloy UCu_{5-x}Pd_x.Comment: 4 pages, 3 figures, REVTe

    Dominance of a clonal green sulfur bacterial population in a stratified lake

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    For many years, the chemocline of the meromictic Lake Cadagno, Switzerland, was dominated by purple sulfur bacteria. However, following a major community shift in recent years, green sulfur bacteria (GSB) have come to dominate. We investigated this community by performing microbial diversity surveys using FISH cell counting and population multilocus sequence typing [clone library sequence analysis of the small subunit (SSU) rRNA locus and two loci involved in photosynthesis in GSB: fmoA and csmCA]. All bacterial populations clearly stratified according to water column chemistry. The GSB population peaked in the chemocline (c. 8 × 106 GSB cells mL−1) and constituted about 50% of all cells in the anoxic zones of the water column. At least 99.5% of these GSB cells had SSU rRNA, fmoA, and csmCA sequences essentially identical to that of the previously isolated and genome-sequenced GSB Chlorobium clathratiforme strain BU-1 (DSM 5477). This ribotype was not detected in Lake Cadagno before the bloom of GSB. These observations suggest that the C. clathratiforme population that has stabilized in Lake Cadagno is clonal. We speculate that such a clonal bloom could be caused by environmental disturbance, mutational adaptation, or invasio

    Hidden non-Fermi liquid behavior due to crystal field quartet

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    We study a realistic Kondo model for crystal field quartet ground states having magnetic and non-magnetic (quadrupolar) exchange couplings with conduction electrons, using the numerical renormalization group method. We focus on a local effect dependent on singlet excited states coupled to the quartet, which reduces the non-magnetic coupling significantly and drives non-Fermi liquid behavior observed in the calculated quadrupolar susceptibility. A crossover from the non-Fermi liquid state to the Fermi liquid state is characterized by a small energy scale very sensitive to the non-magnetic coupling. On the other hand, the Kondo temperature observed in the magnetic susceptibility is less sensitive. The different crystal-field dependence of the two exchange couplings may be related to the different xx dependence of quadrupolar and magnetic ordering temperatures in Cex_xLa1x_{1-x}B6_6.Comment: 7 pages, 5 EPS figures, REVTe

    Anomalous heavy-fermion and ordered states in the filled skutterudite PrFe4P12

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    Specific heat and magnetization measurements have been performed on high-quality single crystals of filled-skutterudite PrFe_4P_{12} in order to study the high-field heavy-fermion state (HFS) and low-field ordered state (ODS). From a broad hump observed in C/T vs T in HFS for magnetic fields applied along the direction, the Kondo temperature of ~ 9 K and the existence of ferromagnetic Pr-Pr interactions are deduced. The {141}-Pr nuclear Schottky contribution, which works as a highly-sensitive on-site probe for the Pr magnetic moment, sets an upper bound for the ordered moment as ~ 0.03 \mu_B/Pr-ion. This fact strongly indicates that the primary order parameter in the ODS is nonmagnetic and most probably of quadrupolar origin, combined with other experimental facts. Significantly suppressed heavy-fermion behavior in the ODS suggests a possibility that the quadrupolar degrees of freedom is essential for the heavy quasiparticle band formation in the HFS. Possible crystalline-electric-field level schemes estimated from the anisotropy in the magnetization are consistent with this conjecture.Comment: 7 pages and 7 figures. Accepted for publication in Phys. Rev.
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