12,773 research outputs found

    Roads, lands, markets, and deforestation : a spatial model of land use in Belize

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    Rural roads promote economic development but also facilitate deforestation. To explore the tradeoffs between development and environmental damage posed by road building, the authors develop and estimate a spatially explicit model of land use. This model takes into account location and land characteristics and predicts land use at each point on the landscape. They find that: (a) market access and distance to roads strongly affect the probability of agricultural use, especially for commercial agriculture; (b) high slopes, poor drainage, and low soil fertility discourage both commercial and semi subsistence agriculture; and (c) semi-subsistence agriculture is especially sensitive to soil acidity and lack nitrogen (confirming anthropological findings that subsistence farmers are shrewd judges of soil). Spatially explicit models are analytically powerful because they exploit rich spatial variation in causal variables, including the precise siting of roads. They are useful for policy because they can pinpoint threats to particular critical habitats and watersheds. This model is a descendant of the venerable von Thunen model. It assumes that land will tend to be devoted to its highest-value use, taking into account tenure and other constraints. The value of a plot for a particular use depends on the land's physical productivity for that use and the farmgate prices of relevant inputs and outputs. A reduced-form, multinomial logit specification of this model calculates implicit values of land in alternative uses as a function of land location and characteristics. The resulting equations can then be used for prediction or analysis. The model was applied to cross-sectional data for 1989-92 for Belize, a forested country currently experiencing rapid expansion of both subsistence and commercial agriculture. A geographic information system was used to manage the spatial data and extract variables based on the three kilometer sample grid. Three land uses were distinguished:"natural"vegetation, comprising forests, woodlands, wetlands, and savanna; semi-subsistence agriculture, comprising traditional milpa (slash-and-burn) cultivation and other nonmechanized cultivation of annual crops; and commercial agriculture, consisting mainly of sugarcane, pasture, citrus, and mechanized production of corn and kidney beans. Two dimensions of distance to market were distinguished: the distance from each sample point to the road, and on-road travel time to the nearest town. Data on a wide variety of land and soil characteristics were also used.Wetlands,Water Conservation,Environmental Economics&Policies,Climate Change,Land Use and Policies,Forestry,Environmental Economics&Policies,Climate Change,Energy and Environment,Wetlands

    Rotation and Macroturbulence in Metal-poor Field Red Giant and Red Horizontal Branch Stars

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    We report the results for rotational velocities, Vrot sin i, and macroturbulence dispersion, zeta(RT), for 12 metal-poor field red giant branch stars and 7 metal-poor field red horizontal branch stars. The results are based on Fourier transform analyses of absorption line profiles from high-resolution (R ~ 120,000), high-S/N (~ 215 per pixel) spectra obtained with the Gecko spectrograph at CFHT. We find that the zeta(RT) values for the metal-poor RGB stars are very similar to those for metal-rich disk giants studied earlier by Gray and his collaborators. Six of the RGB stars have small rotational values, less than 2.0 km/sec, while five show significant rotation, over 3 km/sec. The fraction of rapidly rotating RHB stars is somewhat lower than found among BHB stars. We devise two empirical methods to translate the line-broadening results obtained by Carney et al. (2003, 2008) into Vrot sin i for all the RGB and RHB stars they studied. Binning the RGB stars by luminosity, we find that most metal-poor field RGB stars show no detectable sign, on average, of rotation. However, the most luminous stars, with M(V) <= -1.5, do show net rotation, with mean values of 2 to 4 km/sec, depending on the algorithm employed, and these stars also show signs of radial velocity jitter and mass loss.Comment: accepted for publication in the Astronomical Journa

    Modified Early Warning Scores (MEWS) to support ambulance clinicians’ decisions to transport or treat at home

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    Introduction Modified Early Warning Scores (MEWS), calculated from patients’ vital signs, are used in hospital to identify patients who may benefit from admission or intensive care: higher MEWS indicates greater clinical risk. We aimed to evaluate MEWS to support paramedics’ decisions to transport patients to hospital or treat and leave them at home. Methods We used an interrupted time series design. We trained 19 volunteer paramedics to use MEWS to support decisions to transport or treat and leave at home. We used linear regression to evaluate differences in weekly transportation rates (percentage of patients attended and transported to hospital) and revisit rates (percentage of patients attended, treated at home and subsequently revisited within 7 days), comparing trends in rates 17 weeks prior (pre-MEWS) and 17 weeks post implementation of MEWS. Auto-calculated scores retrospectively applied to all data provided pre-MEWS and were compared with paramedic calculated scores post-MEWS. Results Of the 4140 patients attended, 2208 were excluded owing to missing values (n=1897), recording errors (n=21) or excluded clinical complaints (n=290). From the remaining data (n=1932) there were no significant differences in transportation rates (pre=55±6%; post=63±11%) by catering for the existing increasing trends where the confidence intervals of the regression slopes overlap (pre=0.15; 95%CI -0.51 to 0.80 vs. post=0.54; -0.58 to 1.65). Similarly, there were no significant difference in revisit rates (pre=4±4%; post=2±4%) catering for the similar trends (pre=-0.13; -0.53 to 0.27 vs. post=0.08; -0.33 to 0.49). Paramedic scores were incorrect 39% of the time (n=622). Conclusion MEWS had a minimal effect on transportation or revisit rates. Scores were frequently not calculated or recorded, or incorrectly calculated. Opportunities for ongoing training, clinical support and feedback were limited. A larger study, ensuring adequate ongoing support, is recommended before implementing MEWS on a wider scale

    An evaluation of a multi-site community pharmacy based chronic obstructive pulmonary disease support service

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    Background Chronic obstructive pulmonary disease (COPD) is a progressive chronic condition which can be effectively managed by smoking cessation, optimising prescribed therapy and providing treatment to prevent chest infections from causing hospitalisation. The government agenda in the UK is for community pharmacists to become involved in chronic disease management and COPD is one area where they are ideally located to provide a comprehensive service. Objective To evaluate the effect of a community pharmacy based COPD service on patient outcomes. Method Patients in one UK location were recruited over a 3 month period to receive a community pharmacy based COPD support service consisting of signposting to or provision of smoking cessation service, therapy optimisation, and recommendation to obtain a rescue pack containing steroid and antibiotic to prevent hospitalisation as a result of chest infection. Data was collected over a six month period for all recruited patients. Appropriate clinical outcomes, patient reported medication adherence, quality of life and NHS resource utilisation were measured. Key findings 306 patients accessed the service and full data to enable comparison before and after was available for 137. Significant improvements in patient reported adherence, utilisation of rescue packs, quality of life and a reduction in routine GP visits were identified. The intervention cost was estimated to be off-set by reductions in the use of other NHS services (GP and A&E visits and hospital admissions). Conclusion Results suggest that the service improved patient medicine taking behaviours and that it was cost-effective

    Fluid-Induced Propulsion of Rigid Particles in Wormlike Micellar Solutions

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    In the absence of inertia, a reciprocal swimmer achieves no net motion in a viscous Newtonian fluid. Here, we investigate the ability of a reciprocally actuated particle to translate through a complex fluid that possesses a network using tracking methods and birefringence imaging. A geometrically polar particle, a rod with a bead on one end, is reciprocally rotated using magnetic fields. The particle is immersed in a wormlike micellar (WLM) solution that is known to be susceptible to the formation of shear bands and other localized structures due to shear-induced remodeling of its microstructure. Results show that the nonlinearities present in this WLM solution break time-reversal symmetry under certain conditions, and enable propulsion of an artificial "swimmer." We find three regimes dependent on the Deborah number (De): net motion towards the bead-end of the particle at low De, net motion towards the rod-end of the particle at intermediate De, and no appreciable propulsion at high De. At low De, where the particle time-scale is longer then the fluid relaxation time, we believe that propulsion is caused by an imbalance in the fluid first normal stress differences between the two ends of the particle (bead and rod). At De~1, however, we observe the emergence of a region of network anisotropy near the rod using birefringence imaging. This anisotropy suggests alignment of the micellar network, which is "locked in" due to the shorter time-scale of the particle relative to the fluid

    Soybean (Glycine max) oil bodies and their associated phytochemicals

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    Abstract:  Soybean oil bodies were isolated from 3 cultivars (Ustie, K98, and Elena) and the occurrence of 2 classes of phytochemicals (tocopherol isoforms and isoflavones) and strength of their association with isolated oil bodies was evaluated. Tocopherol is shown to be closely associated with soybean oil bodies; ή-tocopherol demonstrated a significantly greater association with oil bodies over other tocopherol isoforms. Isoflavones do not show a significant physical association with oil bodies, although there is some indication of a passive association of the more hydrophobic aglycones during oil body isolation. Practical Application:  Oil bodies are small droplets of oil that are stored as energy reserves in the seeds of oil seeds, and have the potential to be used as future food ingredients. If oil body suspensions are commercialized on a large scale, knowledge of the association of phytochemicals with oil bodies will be valuable in deciding species of preference and predicting shelf life and nutritional value

    TRAP CROP RADISH: A SUSTAINABLE ALTERNATIVE FOR NEMATICIDE IN SUGAR BEETS

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    Chemical treatment of nematodes in sugar beets can be very costly ($190 per acre), and hazardous, representing significant environmental risks to air, water and human health. Substituting trap crop radish for chemicals, represents a win-win case of sustainable pest control, yielding environmental benefits, higher profit and reduced risk.Crop Production/Industries,

    Sensing and control in dual-recycling laser interferometer gravitational-wave detectors

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    We introduce length-sensing and control schemes for the dual-recycled cavity-enhanced Michelson interferometer configuration proposed for the Advanced Laser Interferometer Gravitational Wave Observatory (LIGO). We discuss the principles of this scheme and show methods that allow sensing and control signals to be derived. Experimental verification was carried out in three benchtop experiments that are introduced. We present the implications of the results from these experiments for Advanced LIGO and other future interferometric gravitational-wave detectors
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