901 research outputs found

    Impacts of Cattle Grazing Management on Sediment and Phosphorus Loads in Surface Waters

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    In 2001 (yr 1), 2002 (yr 2), and 2003 (yr 3), three blocks of five 1-ac paddocks were grazed by beef cows on hills at the Iowa State University Rhodes Research and Demonstration Farm to determine the effects of grazing management on phosphorus (P) and sediment runoff from pastureland. Grazing management treatments included an ungrazed control (UG), summer hay harvest with winter stockpiled grazing (HS), grazing by continuous stocking to a residual sward height of 2 in. (2C), rotational stocking to a residual sward height of 2 in. (2R), and rotational stocking to a residual sward height of 4 in (4R). At four times (late spring, mid-summer, early autumn, and early the subsequent spring) in each year, rainfall simulations were conducted at 6 sites within each paddock. Rainfall simulators dripped at a rate of 2.8 in./hr over a 5.4-ft2 area for a period of 1.5 hours. Runoff was collected and analyzed for total sediment, total P, and total soluble P. Simultaneous to each rainfall simulation, ground cover, penetration resistance, surface roughness, slope, the contents of P and moisture of the soil, sward height and forage mass were measured. Sediment flow was not affected by forage management practice. There was no difference between UG, HS, 4R in the amount of total P or soluble P lost in runoff, but greater amounts of total and soluble P were lost from 2C and 2R than from the other management practices (P\u3c0.05). A greater amount of sediment was lost from the pastures during the late spring period than during other parts of the year (P\u3c0.05). Losses of sediment, total P, and soluble P from pastures can be controlled by suitable grazing management practices

    Bose-Einstein Condensation of 88^{88}Sr Through Sympathetic Cooling with 87^{87}Sr

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    We report Bose-Einstein condensation of 88^{88}Sr, which has a small, negative s-wave scattering length (a88=2a_{88}=-2\,a0a_0). We overcome the poor evaporative cooling characteristics of this isotope by sympathetic cooling with 87^{87}Sr atoms. 87^{87}Sr is effective in this role in spite of the fact that it is a fermion because of the large ground state degeneracy arising from a nuclear spin of I=9/2I=9/2, which reduces the impact of Pauli blocking of collisions. We observe a limited number of atoms in the condensate (Nmax104N_{max}\approx 10^4) that is consistent with the value of a88a_{88} and the optical dipole trap parameters.Comment: 4 pages, 4 figure

    Degenerate Fermi Gas of 87^{87}Sr

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    We report quantum degeneracy in a gas of ultra-cold fermionic 87^{87}Sr atoms. By evaporatively cooling a mixture of spin states in an optical dipole trap for 10.5\,s, we obtain samples well into the degenerate regime with T/TF=0.26.06+.05T/T_F=0.26^{+.05}_{-.06}. The main signature of degeneracy is a change in the momentum distribution as measured by time-of-flight imaging, and we also observe a decrease in evaporation efficiency below T/TF0.5T/T_F \sim 0.5.Comment: 4 pages, 3 figure

    Runaway evaporation for optically dressed atoms

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    Forced evaporative cooling in a far-off-resonance optical dipole trap is proved to be an efficient method to produce fermionic- or bosonic-degenerated gases. However in most of the experiences, the reduction of the potential height occurs with a diminution of the collision elastic rate. Taking advantage of a long-living excited state, like in two-electron atoms, I propose a new scheme, based on an optical knife, where the forced evaporation can be driven independently of the trap confinement. In this context, the runaway regime might be achieved leading to a substantial improvement of the cooling efficiency. The comparison with the different methods for forced evaporation is discussed in the presence or not of three-body recombination losses

    Medication Management: The Macrocognitive Workflow of Older Adults With Heart Failure

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    BACKGROUND: Older adults with chronic disease struggle to manage complex medication regimens. Health information technology has the potential to improve medication management, but only if it is based on a thorough understanding of the complexity of medication management workflow as it occurs in natural settings. Prior research reveals that patient work related to medication management is complex, cognitive, and collaborative. Macrocognitive processes are theorized as how people individually and collaboratively think in complex, adaptive, and messy nonlaboratory settings supported by artifacts. OBJECTIVE: The objective of this research was to describe and analyze the work of medication management by older adults with heart failure, using a macrocognitive workflow framework. METHODS: We interviewed and observed 61 older patients along with 30 informal caregivers about self-care practices including medication management. Descriptive qualitative content analysis methods were used to develop categories, subcategories, and themes about macrocognitive processes used in medication management workflow. RESULTS: We identified 5 high-level macrocognitive processes affecting medication management-sensemaking, planning, coordination, monitoring, and decision making-and 15 subprocesses. Data revealed workflow as occurring in a highly collaborative, fragile system of interacting people, artifacts, time, and space. Process breakdowns were common and patients had little support for macrocognitive workflow from current tools. CONCLUSIONS: Macrocognitive processes affected medication management performance. Describing and analyzing this performance produced recommendations for technology supporting collaboration and sensemaking, decision making and problem detection, and planning and implementation

    The Effects of Conjoint Behavioral Consultation: Results of a 4-Year Investigation

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    Conjoint behavioral consultation (CBC) is a structured indirect form of service delivery in which parents, teachers, and other support staff are joined to work together to address the academic, social, or behavioral needs of an individual for whom all parties bear some responsibility. In this article, outcome data from 4 years of federally funded projects in the area of CBC are presented. Thirty graduate students were trained in CBC and were responsible for providing consultation services to parents and teachers of students with disabilities or at risk for academic failure. Consultation clients included 52 students with disabilities such as behavior disorders, attention-deficit hyperactivity disorder, anxiety, and learning disabilities. The primary research objective concerned assessing the efficacy of CBC across home and school settings. Secondarily, a prediction model was investigated based on client age, case complexity, and severity of symptoms. Perception of effectiveness, process acceptability, and consultee satisfaction with consultants was also investigated. Meaningful effect sizes were yielded across home and school settings. A model fitting client age and symptom severity was found to predict school effect size relatively well. Consultees’ perceptions of effectiveness, acceptability of CBC, and satisfaction with consultants were also favorable. Implications of these findings and directions for future research are explored

    Repumping and spectroscopy of laser-cooled Sr atoms using the (5s5p)3P2 - (5s4d)3D2 transition

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    We describe repumping and spectroscopy of laser-cooled strontium (Sr) atoms using the (5s5p)3P2 - (5s4d)3D2 transition. Atom number in a magneto-optical trap is enhanced by driving this transition because Sr atoms that have decayed into the (5s5p)3P2 dark state are repumped back into the (5s2)1S0 ground state. Spectroscopy of 84Sr, 86Sr, 87Sr, and 88Sr improves the value of the (5s5p)3P2 - (5s4d)3D2 transition frequency for 88Sr and determines the isotope shifts for the transition.Comment: 4 pages, 5 figure

    Doping Effect of Nano-Diamond on Superconductivity and Flux Pinning in MgB2

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    Doping effect of diamond nanoparticles on the superconducting properties of MgB2 bulk material has been studied. It is found that the superconducting transition temperature Tc of MgB2 is suppressed by the diamond-doping, however, the irreversibility field Hirr and the critical current density Jc are systematically enhanced. Microstructural analysis shows that the diamond-doped MgB2 superconductor consists of tightly-packed MgB2 nano-grains (~50-100 nm) with highly-dispersed and uniformly-distributed diamond nanoparticles (~10-20 nm) inside the grains. High density of dislocations and diamond nanoparticles may take the responsibility for the enhanced flux pinning in the diamond-doped MgB2.Comment: 16 pages, 6 figure

    Identification and validation of genetic variants predictive of gait in standardbred horses

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    Several horse breeds have been specifically selected for the ability to exhibit alternative patterns of locomotion, or gaits. A premature stop codon in the gene DMRT3 is permissive for “gaitedness” across breeds. However, this mutation is nearly fixed in both American Standardbred trotters and pacers, which perform a diagonal and lateral gait, respectively, during harness racing. This suggests that modifying alleles must influence the preferred gait at racing speeds in these populations. A genome-wide association analysis for the ability to pace was performed in 542 Standardbred horses (n = 176 pacers, n = 366 trotters) with genotype data imputed to ~74,000 single nucleotide polymorphisms (SNPs). Nineteen SNPs on nine chromosomes (ECA1, 2, 6, 9, 17, 19, 23, 25, 31) reached genome-wide significance (p < 1.44 x 10−6). Variant discovery in regions of interest was carried out via whole-genome sequencing. A set of 303 variants from 22 chromosomes with putative modifying effects on gait was genotyped in 659 Standardbreds (n = 231 pacers, n = 428 trotters) using a high-throughput assay. Random forest classification analysis resulted in an out-of-box error rate of 0.61%. A conditional inference tree algorithm containing seven SNPs predicted status as a pacer or trotter with 99.1% accuracy and subsequently performed with 99.4% accuracy in an independently sampled population of 166 Standardbreds (n = 83 pacers, n = 83 trotters). This highly accurate algorithm could be used by owners/trainers to identify Standardbred horses with the potential to race as pacers or as trotters, according to the genotype identified, prior to initiating training and would enable fine-tuning of breeding programs with designed matings. Additional work is needed to determine both the algorithm’s utility in other gaited breeds and whether any of the predictive SNPs play a physiologically functional role in the tendency to pace or tag true functional alleles
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