6,810 research outputs found

    Effects of Nitrogen, Lime, and Boron on Candle Rape Grown in the Trapper Creek and Pt. MacKenzie Areas of Southcentral Alaska

    Get PDF
    When growers in the Susitna Valley and later in the Pt. MacKenzie area of southcentral Alaska inquired as to the feasibility of growing rapeseed, we decided to determine the crops suitability and performance by conducting a field experiment. Bolton (1980) had attempted to predict the feasibility of producing rapeseed in Alaska's interior, but no research had been done in southcentral Alaska. We conducted one study from 1979 through 1981 on Rabideux silt loam (pH 5.1) near Trapper Creek and another from 1982 through 1984 on Kashwitna silt loam (pH 5.4) on the University of Alaska' s research tract in the Pt. MacKenzie area. The first area had been cleared prior to 197 8. This area was rototilled and roots removed in September 1978. The second area was on a tract cleared during the winter of 1981. After clearing, rotary plowing was done twice on the area. During the summer of 1981, roots were removed , and a field cultivator was used twice to loosen and bring roots to the surface

    Effects of Potassium, Sulfur, Nitrogen Rate, And Nitrogen Source on Bromegrass Forage Yield and Composition

    Get PDF
    Production of adequate , high-quality forage is essential for Alaska's livestock industry. Smooth bromegrass (Bromus inermis) is the dominant and most dependable perennial forage crop in the Matanuska Valley and other areas of Alaska. Four areas of Knik silt loam on the University of Alaska's Matanuska Research Farm near Palmer were seeded to bromegrass and were used over a period of 18 years to determine the need of high-yielding bromegrass for applications of potassium (K) and sulfur (S). A bromegrass field on the Woods estate two miles south of Palmer was selected in 1976 for a study comparing three rates of two nitrogen (N) sources with and without S. The soil type was Bodenburg silt loam

    Adverse Effects of Cholinesterase Inhibitors in Dementia, According to the Pharmacovigilance Databases of the United-States and Canada.

    Get PDF
    This survey analyzes two national pharmacovigilance databases in order to determine the major adverse reactions observed with the use of cholinesterase inhibitors in dementia. We conducted a statistical analysis of the Food and Drug Administration Adverse Event Reporting System (FAERS) and the Canada Vigilance Adverse Reaction Database (CVARD) concerning the side effects of cholinesterase inhibitors. The statistics calculated for each adverse event were the frequency and the reporting odds ratios (ROR). A total of 9877 and 2247 reports were extracted from the FAERS and CVARD databases, respectively. A disproportionately higher frequency of reports of death as an adverse event for rivastigmine, compared to the other acetylcholinesterase inhibiting drugs, was observed in both the FAERS (ROR = 3.42; CI95% = 2.94-3.98; P<0.0001) and CVARD (ROR = 3.67; CI95% = 1.92-7.00; P = 0.001) databases. While cholinesterase inhibitors remain to be an important therapeutic tool against Alzheimer's disease, the disproportionate prevalence of fatal outcomes with rivastigmine compared with alternatives should be taken into consideration

    Propeller Slipstream Effects As Determined From Wing Pressure Distribution Of A Large-Scale Six-Propeller VTOL Model At Static Thrust

    Get PDF
    Propeller slipstream effects as determined from wing pressure distribution of a large-scale six-propeller vtol model at static thrus

    Semileptonic Decays of Heavy Lambda Baryons in a Quark Model

    Full text link
    The semileptonic decays of Lambda_c and Lambda_b are treated in the framework of a constituent quark model. Both nonrelativistic and semirelativistic Hamiltonians are used to obtain the baryon wave functions from a fit to the spectra, and the wave functions are expanded in both the harmonic oscillator and Sturmian bases. The latter basis leads to form factors in which the kinematic dependence on q^2 is in the form of multipoles, and the resulting form factors fall faster as a function of q^2 in the available kinematic ranges. As a result, decay rates obtained in the two models using the Sturmian basis are significantly smaller than those obtained using the harmonic oscillator basis. In the case of the Lambda_c, decay rates calculated using the Sturmian basis are closer to the experimentally reported rates. However, we find a semileptonic branching fraction for the Lambda_c to decay to excited Lambda* states of 11% to 19%, in contradiction with what is assumed in available experimental analyses. Our prediction for the Lambda_b semileptonic decays is that decays to the ground state Lambda_c provide a little less than 70% of the total semileptonic decay rate. For the decays Lambda_b to Lambda_c, the analytic form factors we obtain satisfy the relations expected from heavy-quark effective theory at the non-recoil point, at leading and next-to-leading orders in the heavy-quark expansion. In addition, some features of the heavy-quark limit are shown to naturally persist as the mass of the heavy quark in the daughter baryon is decreased.Comment: 51 pages, 8 figures, submitted to Physical Review

    Ant colony optimisation and local search for bin-packing and cutting stock problems

    Get PDF
    The Bin Packing Problem and the Cutting Stock Problem are two related classes of NP-hard combinatorial optimization problems. Exact solution methods can only be used for very small instances, so for real-world problems, we have to rely on heuristic methods. In recent years, researchers have started to apply evolutionary approaches to these problems, including Genetic Algorithms and Evolutionary Programming. In the work presented here, we used an ant colony optimization (ACO) approach to solve both Bin Packing and Cutting Stock Problems. We present a pure ACO approach, as well as an ACO approach augmented with a simple but very effective local search algorithm. It is shown that the pure ACO approach can compete with existing evolutionary methods, whereas the hybrid approach can outperform the best-known hybrid evolutionary solution methods for certain problem classes. The hybrid ACO approach is also shown to require different parameter values from the pure ACO approach and to give a more robust performance across different problems with a single set of parameter values. The local search algorithm is also run with random restarts and shown to perform significantly worse than when combined with ACO

    Semileptonic Hyperon Decays and CKM Unitarity

    Full text link
    Using a technique that is not subject to first-order SU(3) symmetry breaking effects, we determine the VusV_{us} element of the CKM matrix from data on semileptonic hyperon decays. We obtain VusV_{us} =0.2250(27). This value is of similar precision to the one derived from Kl3K_{l3}, but higher and in better agreement with the unitarity requirement, Vud2+Vus2+Vub2=1|V_{ud}|^2+|V_{us}|^2+|V_{ub}|^2=1.Comment: 3 pages, 1 tabl

    Leveraging different meronym discovery methods for bridging resolution in French

    Get PDF
    International audienceThis paper presents a statistical system for resolving bridging descriptions in French, a language for which current lexical resources have a very low overage. The system is similar to that developed for English by Poesio but it was enriched to integrate meronymic information extracted automatically from both web queries and raw text using syntactic patterns. Through various experiments on the DEDE corpus, we show that although still mediocre the performance of our system compare favorably to those obtained by Poesio for English. In addition, our evaluation indicates that the different meronym extraction methods have a cumulative effect, but that the text pattern-based extraction method is more robust and leads to higher accuracy than the web-based approach

    The effects of age on associations between markers of HIV progression and markers of metabolic function including albumin, haemoglobin and lipid concentrations.

    Get PDF
    OBJECTIVES: We investigated whether age modified associations between markers of HIV progression, CD4 T lymphocyte count and HIV RNA viral load (VL), and the following markers of metabolic function: albumin, haemoglobin, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC). METHODS: A retrospective analysis of data from the United Kingdom Collaborative HIV Cohort was carried out. Analyses were limited to antiretroviral-naïve subjects to focus on the impact of HIV disease itself. A total of 16670 subjects were included in the analysis. Multilevel linear regression models assessed associations between CD4 count/VL and each of the outcomes. Statistical tests for interactions assessed whether associations differed among age groups. RESULTS: After adjustment for gender and ethnicity, there was evidence that lower CD4 count and higher VL were associated with lower TC, LDL-C, haemoglobin and albumin concentrations but higher triglyceride concentrations. Age modified associations between CD4 count and albumin (P 50 years, a 50 cells/μL lower CD4 count correlated with a 2.4 [95% confidence interval (CI) 1.7-3.0], 3.6 (95% CI 3.2-4.0) and 5.1 (95% CI 4.0-6.1) g/L lower haemoglobin concentration and a 0.09 (95% CI 0.07-0.11), 0.12 (95% CI 0.11-0.13) and 0.16 (95% CI 0.13-0.19) g/L lower albumin concentration, respectively. CONCLUSIONS: We present evidence that age modifies associations between CD4 count and plasma albumin and haemoglobin levels. A given reduction in CD4 count was associated with a greater reduction in haemoglobin and albumin concentrations among older people living with HIV. These findings increase our understanding of how the metabolic impact of HIV is influenced by age

    Discovery of Two T Dwarf Companions with the Spitzer Space Telescope

    Get PDF
    We report the discovery of T dwarf companions to the nearby stars HN Peg (G0V, 18.4 pc, ~0.3 Gyr) and HD 3651 (K0V, 11.1 pc, ~7 Gyr). During an ongoing survey of 5'x5' fields surrounding stars in the solar neighborhood with IRAC aboard the Spitzer Space Telescope, we identified these companions as candidate T dwarfs based on their mid-IR colors. Using near-IR spectra obtained with SpeX at the NASA IRTF, we confirm the presence of methane absorption that characterizes T dwarfs and measure spectral types of T2.5+/-0.5 and T7.5+/-0.5 for HN Peg B and HD 3651 B, respectively. By comparing our Spitzer data to images from 2MASS obtained several years earlier, we find that the proper motions of HN Peg B and HD 3651 B are consistent with those of the primaries, confirming their companionship. HN Peg B and HD 3651 B have angular separations of 43.2" and 42.9" from their primaries, which correspond to projected physical separations of 795 and 476 AU, respectively. A comparison of their luminosities to the values predicted by theoretical evolutionary models implies masses of 0.021+/-0.009 and 0.051+/-0.014 Msun for HN Peg B and HD 3651 B. In addition, the models imply an effective temperature for HN Peg B that is significantly lower than the values derived for other T dwarfs at similar spectral types, which is the same behavior reported by Metchev & Hillenbrand for the young late-L dwarf HD 203030 B. Thus, the temperature of the L/T transition appears to depend on surface gravity. Meanwhile, HD 3651 B is the first substellar companion directly imaged around a star that is known to harbor a close-in planet from RV surveys. The discovery of this companion supports the notion that the high eccentricities of close-in planets like the one near HD 3651 may be the result of perturbations by low-mass companions at wide separations.Comment: Astrophysical Journal, in pres
    corecore