4,092 research outputs found

    Potential economic gains from using forage legumes in organic livestock systems in northern Europe

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    This report was presented at the UK Organic Research 2002 Conference of the Colloquium of Organic Researchers (COR). Forage legumes, with their ability to fix nitrogen biologically, seem especially attractive for organic livestock production. In an attempt to assess their true potential, this study draws on a four-year trial conducted at 12 sites in northern Europe with four different forage legumes. One third of the sites were managed as organic systems, with the harvested forage being fed as silage to dairy cows. Based on the trial results, an economic assessment has been made of the potential of forage legumes to improve the competitive edge of organic dairy systems, relative to conventional grass-based ones. Although the results suggest that the organic milk price premium plays a major role in determining the comparative profitability of organic dairy systems, the use of forage legumes also gives a significant cost advantage to organic production

    A framework for assessing crop production from rotations

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    This report was presented at the UK Organic Research 2002 Conference of the Colloquium of Organic Researchers (COR). Organic farming systems rely on the management of biological cycles for the provision of nutrients, which are crucial to maximising the production from the system. Rotations based on the use of grass-legume leys are central to the concept of organic farming systems, because they have the potential to support both animal production, and a subsequent, exploitative, arable cropping phase. A major challenge in organic farming is managing the supply of nitrogen, since it has a key role in governing both productivity and environmental impact. Hence, within a rotational system, there is a need to understand the complex interactions that are occurring between crop species and management, livestock production system and the impact of soil and climate on these processes. To understand these interactions, a framework is being developed for rotational farming systems that describes the soil nitrogen, crop growth and livestock production. The framework must address questions that are relevant to researchers and extensions workers. Typical questions relate to the management of nutrients in the short and long-term. Additionally, there are concerns over the impact of weeds, pests and diseases on productivity, as well as the impact of adopting new strategies or crops on the farming system

    Psychometric Evaluation of an Instrument to Measure Hispanic Mothers’ Normative Beliefs, Intentions, Past Experience and Past Behavior Related to the Discussion of Sex-Related Topics with their Adolescent Daughters

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    Aim: The aim of this project was to describe the psychometric properties of a recently developed instrument that measures Hispanic mother normative beliefs, intentions, past experience, and past behavior regarding the Discussion of Sex-Related Topics (DSRTs) with their adolescent daughters. Background: The DSRTs between Hispanic mothers and their adolescent daughters is important because this interaction has been found to be a protective factor against the daughter’s risk for STDs and unintended pregnancy. Hispanic mother talk less with their daughters about sex-related topics (SRTs) than other ethnic groups. The Rodriguez Normative Belief Instrument (RNBI) has been established to measure normative beliefs, normative beliefs, past behavior, and past experience regarding Hispanic mothers’ DSRTs with their adolescent daughters. Method: The 44-item RNBI was developed based on the Theory of Planned Behavior and the Parent-Based Expansion Theory of Planned Behavior. A convenience sample of 119 Hispanic mothers of adolescent females grades 6 through 8 from two Midwestern Catholic Middle Schools was enrolled completed the instrument. Paper and pen instruments were administered in the language of the participant’s choice, English or Spanish. Results: The entire RNBI and each of the four subscales demonstrated acceptable internal consistency (Cronbach’s alpha = .70). The overall reliability of the RNBI was .82 with the normative beliefs subscale of .85, intentions .88, past behavior .89, and past experience .88. Confirmatory factor analysis validated the four subscales. Conclusion: Psychometric analyses indicated that the RNBI demonstrates acceptable validity and reliability for this sample

    Anesthesia Preoperative Clinic Referral for Elevated Hba1c Reduces Complication Rate in Diabetic Patients Undergoing Total Joint Arthroplasty

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    Background: Diabetes mellitus (DM) is risk factor for complications after orthopedic surgery. Objectives: We tested the hypothesis that anesthesia preoperative clinic (APC) referral for elevated glycosylated hemoglobin (HbA1c) reduces complication rate after total joint arthroplasty (TJA). Patients and Methods: Patients (n = 203) with and without DM were chosen from 1,237 patients undergoing TJA during 2006 - 12. Patients evaluated in the APC had surgery in 2006 - 8 regardless of HbA1c (uncontrolled). Those evaluated between in subsequent two-year intervals were referred to primary care for HbA1c ≥ 10% and ≥ 8%, respectively, to improve DM control before surgery. Complications and mortality were quantified postoperatively and at three, six, and twelve months. Length of stay (LOS) and patients requiring a prolonged LOS (\u3e 5 days) were recorded. Results: Patients (197 men, 6 women) underwent 71, 131, and 1 total hip, knee, and shoulder replacements, respectively. Patients undergoing TJA with uncontrolled HbA1c and those with HbA1c \u3c 10%, but not those with HbA1c \u3c 8%, had a higher incidence of coronary disease and hypercholesterolemia than patients without DM. An increase in complication rate was observed in DM patients with uncontrolled HbA1c versus patients without DM (P \u3c 0.001); the complication rate progressively decreased with tighter HbA1c control. More DM patients with preoperative HbA1c that was uncontrolled or ≥ 10% required prolonged LOS versus those without DM (P \u3c 0.001 and P = 0.0404, respectively). Conclusions: APC referral for elevated HbA1c reduces complication rate and the incidence of prolonged hospitalization during the first year after surgery in diabetics undergoing TJA

    Comparison of the Effects of Ice and 3.5% Menthol Gel on Blood Flow and Muscle Strength of the Lower Arm

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    Context: Soft-tissue injuries are commonly treated with ice or menthol gels. Few studies have compared the effects of these treatments on blood flow and muscle strength. Objective: To compare blood flow and muscle strength in the forearm after an application of ice or menthol gel or no treatment. Design: Repeated measures design in which blood-flow and muscle-strength data were collected from subjects under 3 treatment conditions. Setting: Exercise physiology laboratory. Participants: 17 healthy adults with no impediment to the blood flow or strength in their right arm, recruited through word of mouth. Intervention: Three separate treatment conditions were randomly applied topically to the right forearm: no treatment, 0.5 kg of ice, or 3.5 mL of 3.5% menthol gel. To avoid injury ice was only applied for 20 min. Main Outcome Measures: At each data-collection session blood flow (mL/min) of the right radial artery was determined at baseline before any treatment and then at 5, 10, 15, and 20 min after treatment using Doppler ultrasound. Muscle strength was assessed as maximum isokinetic flexion and extension of the wrist at 30°/s 20, 25, and 30 min after treatment. Results: The menthol gel reduced (–42%, P \u3c .05) blood flow in the radial artery 5 min after application but not at 10, 15, or 20 min after application. Ice reduced (–48%, P \u3c .05) blood flow in the radial artery only after 20 min of application. After 15 min of the control condition blood flow increased (83%, P \u3c .05) from baseline measures. After the removal of ice, wrist-extension strength did not increase per repeated strength assessment as it did during the control condition (9–11%, P \u3c .05) and menthol-gel intervention (8%, P \u3c .05). Conclusions: Menthol has a fast-acting, short-lived effect of reducing blood flow. Ice reduces blood flow after a prolonged duration. Muscle strength appears to be inhibited after ice application

    Elastic response of [111]-tunneling impurities

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    We study the dynamic response of a [111] quantum impurity, such as lithium or cyanide in alkali halides, with respect to an external field coupling to the elastic quadrupole moment. Because of the particular level structure of a eight-state system on a cubic site, the elastic response function shows a biexponential relaxation feature and a van Vleck type contribution with a resonance frequency that is twice the tunnel frequency Δ/\Delta/\hbar. This basically differs from the dielectric response that does not show relaxation. Moreover, we show that the elastic response of a [111] impurity cannot be reduced to that of a two-level system. In the experimental part, we report on recent sound velocity and internal friction measurements on KCl doped with cyanide at various concentrations. At low doping (45 ppm) we find the dynamics of a single [111] impurity, whereas at higher concentrations (4700 ppm) the elastic response rather indicates strongly correlated defects. Our theoretical model provides a good description of the temperature dependence of δv/v\delta v/v and Q1Q^{-1} at low doping, in particular the relaxation peaks, the absolute values of the amplitude, and the resonant contributions. From our fits we obtain the value of the elastic deformation potential γt=0.192\gamma_t=0.192 eV.Comment: 19 pages, 5 figure

    Low temperature acoustic properties of amorphous silica and the Tunneling Model

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    Internal friction and speed of sound of a-SiO(2) was measured above 6 mK using a torsional oscillator at 90 kHz, controlling for thermal decoupling, non-linear effects, and clamping losses. Strain amplitudes e(A) = 10^{-8} mark the transition between the linear and non-linear regime. In the linear regime, excellent agreement with the Tunneling Model was observed for both the internal friction and speed of sound, with a cut-off energy of E(min) = 6.6 mK. In the non-linear regime, two different behaviors were observed. Above 10 mK the behavior was typical for non-linear harmonic oscillators, while below 10 mK a different behavior was found. Its origin is not understood.Comment: 1 tex file, 6 figure

    Soft Interaction Between Dissolved Dendrimers: Theory and Experiment

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    Using small-angle neutron scattering and liquid integral equation theory, we relate the structure factor of flexible dendrimers of 4th generation to their average shape. The shape is measured as a radial density profile of monomers belonging to a single dendrimer. From that, we derive an effective interaction of Gaussian form between pairs of dendrimers and compute the structure factor using the hypernetted chain approximation. Excellent agreement with the corresponding experimental results is obtained, without the use of adjustable parameters. The present analysis thus strongly supports the previous finding that flexible dendrimers of low generation present fluctuating structures akin to star polymers.Comment: 20 pages, 4 figures, submitted to Macromolecules on July 24, 200
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