1,061 research outputs found
The Southern Military Tradition: Sociodemographic Factors, Cultural Legacy, and United States Army Enlistments
Throughout the history of the United States, the South has had higher levels of military service than other regions of the country. Scholars regularly refer to this phenomenon as a “Southern military tradition.” The reasons behind this overrepresentation are not completely understood. Do Southern sociodemographic characteristics make it a preferred recruiting area relative to other regions in the United States, or is there something distinctive about the cultural legacy of Southern history that encourages and supports military service? Using a unique data set that includes county- level active duty army enlistments and sociodemographic information, we show that Southern counties have significantly higher enlistment rates than counties in the Northeast and Midwest. These differences disappear when sociodemographic factors, such as fewer college graduates and a prominent presence of Evangelical Christians, are taken into account. These findings suggest that population characteristics may be a stronger driver of current regional disparities in military service than an inherited Southern military tradition
Effect of Timing and Intensity of Drought on Perennial Ryegrass Seed Yield
Perennial ryegrass seed worth about $50 million is produced annually in Canterbury, New Zealand (Rowarth 1998). Ryegrass seed production in New Zealand is often affected by drought, reducing both seed number and seed size (Rolston et al., 1994). Irrigation management recommendations are not currently available for farmers growing ryegrass seed crops. To quantify the effect of water stress on perennial ryegrass seed yield, we carried out an experiment in a rainshelter where rainfall was excluded from experimental plots otherwise exposed to normal weather (Martin et al., 1990)
Reflectivity and Microwave Absorption in Crystals with Alternating Intrinsic Josephson Junctions
We compute the frequency and magnetic field dependencies of the reflectivity
in layered superconductors with two alternating intrinsic Josephson
junctions with different critical current densities and quasiparticle
conductivities for the electric field polarized along the c-axis. The parameter
describing the electronic compressibility of the layers and the charge
coupling of neighboring junctions was extracted for the
SmLaSrCuO superconductor from two independent
optical measurements, the fit of the loss function at zero magnetic
field and the magnetic field dependence of the peak positions in .
The experiments are consistent with a free electron value for near
the Josephson plasma frequencies.Comment: 4 pages, 4 postscript figures, misprints in table correcte
Impact of source of infection and vancomycin AUC0–24/MICBMD targets on treatment failure in patients with methicillin-resistant Staphylococcus aureus bacteraemia
AbstractDespite recent controversies about toxicity and reduced efficacy, vancomycin remains the current treatment of choice for methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia. The parameter associated with treatment success is the vancomycin 24-h area under concentration-time curve to MIC ratio (AUC0–24/MIC). We aimed to determine the utility of calculated AUCs and explore the optimal AUC0–24/MIC targets associated with treatment success. In this single-centre retrospective observational cohort study of 127 patients with MRSA bacteraemia, forty-five (35.4%) did not respond to vancomycin treatment. Patient characteristics were essentially the same between those who did not respond to vancomycin treatment and those with treatment success, with independent predictors of treatment failure being source of bacteraemia (odds ratio (OR), 4.29; 95% confidence interval (CI), 1.50–12.26; p 0.007) and not achieving an AUC0–24/MICBMD (using broth microdilution) target of ≥398 (OR, 11.4; 95% CI, 4.57–28.46; p< 0.001). Bacteraemic source-specific thresholds were observed with a higher AUC0–24/MICBMD target of 440 required for high-risk sources (e.g. infective endocarditis) compared with 330 for low-risk sources (line related bacteraemia). Overall treatment success in patients with MRSA bacteraemia was associated with a vancomycin AUC0–24/MICBMD target of ≥398, with source-specific targets observed. Future vancomycin practice guidelines will need to take into account MIC methodology, source of bacteraemia and patient populations prior to setting targets and monitoring recommendations
Sowing Date Affects Dry Matter Yield of Fodder Beet (\u3ci\u3eBeta vulgaris\u3c/i\u3e L.) Crops and Farm Profitability
Fodder beet (Beta vulgaris L.) is a high yielding and high energy supplementary ruminant feed. Including the crop in a pasture system means loss in production and additional costs during crop establishment, but economic benefits may be recovered with increased seasonal productivity and feed quality. In this study, the Agricultural Production Systems sIMulator was used to estimate herbage production of a typical dairy farm in the Canterbury region of New Zealand based on using a ryegrass (Lolium perenne L.)-clover (Trifolium repens L.) pasture (“Pasture only”) or pasture in combination with fodder beet as winter feed (“Pasture+Fodder beet (FB)”). Mean yields of pasture were used to estimate the potential pasture yield lost from spraying out paddocks 1 month before establishing fodder beet. Fodder beet (‘Rivage’) yields from a 2014 sowing date trial: 19 September (Sep-FB), 17 October (Oct-FB), 17 November (Nov-FB), and 15 December (Dec-FB) were used. Dry matter (DM) yield was determined on 15 June 2015. Yield was 27 t DM/ha for both Sep-FB and Oct-FB and was reduced by 23 and 32% in Nov-FB and Dec-FB, respectively. The total annual yield for “Pasture only” was 16.7 t DM/ha compared with adjusted yield of 29.5, 30.2, 25.7 and 24.9 t DM/ha for “Pasture+Sep-FB”, “Pasture+Oct-FB”, “Pasture+Nov-FB” and “Pasture+Dec-FB”, respectively. Production cost was NZ0.09/kg DM for “Pasture only”. Production costs increased to NZ0.12/kg DM for “Pasture+Dec-FB”, but revenue from sale of surplus feed partially offset these costs. Our results show that sowing in October was the most profitable option. Yield gains from sowing fodder beet in September are unlikely because of low temperatures limiting crop growth. Delaying sowing can increase production costs and yield penalty, but potential returns are greater, compared with “Pasture only”
Optical Properties of Crystals with Spatial Dispersion: Josephson Plasma Resonance in Layered Superconductors
We derive the transmission coefficient, , for grazing incidence of
crystals with spatial dispersion accounting for the excitation of multiple
modes with different wave vectors for a given frequency . The
generalization of the Fresnel formulas contains the refraction indices of these
modes as determined by the dielectric function . Near
frequencies , where the group velocity vanishes, depends
also on an additional parameter determined by the crystal microstructure. The
transmission is significantly suppressed, if one of the excited modes is
decaying into the crystal. We derive these features microscopically for the
Josephson plasma resonance in layered superconductors.Comment: 4 pages, 2 figures, epl.cls style file, minor change
Angular dependent vortex pinning mechanisms in YBCO coated conductors and thin films
We present a comparative study of the angular dependent critical current
density in YBa2Cu3O7 films deposited on IBAD MgO and on single crystal MgO and
SrTiO3 substrates. We identify three angular regimes where pinning is dominated
by different types of correlated and uncorrelated defects. We show that those
regimes are present in all cases, indicating that the pinning mechanisms are
the same, but their extension and characteristics are sample dependent,
reflecting the quantitative differences in texture and defect density. In
particular, the more defective nature of the films on IBAD turns into an
advantage as it results in stronger vortex pinning, demonstrating that the
critical current density of the films on single crystals is not an upper limit
for the performance of the IBAD coated conductors.Comment: 14 pages, 3 figures. Submitted to AP
Irrigation Management Strategies for Fodder Beet (\u3ci\u3eBeta vulgaris\u3c/i\u3e L.) Crops
The production of fodder beet (Beta vulgaris L.) in New Zealand is concentrated in the South Island, and often requires irrigation to achieve high yields. Development of efficient irrigation management strategies requires information on the effect of timing and rate of irrigation on crop growth. A field study was conducted on a moderately deep soil at Chertsey, Canterbury, New Zealand, to evaluate crop growth responses to five irrigation managements: Rain-fed (control), weekly replacement of full evapotranspiration (FullET-weekly), and 50% of evapotranspiration replaced weekly (HalfET-weekly), fortnightly (HalfET-2weekly) or 3-weekly (HalfET-3weekly). Irrigation to replace ET was adjusted to account for rainfall received between irrigation events. The crop was sown on 11 October 2015. Dry matter (DM) and green leaf area index (LAI) were quantified at 4-weekly intervals from 21 December 2015 until 16 May 2016. Water use efficiency (WUE) was calculated from weekly time domain reflectometry and neutron probe measurements of volumetric soil water content (to 0.8 m depth) and crop biomass. Final yield was lowest for Rain-fed (17.1 t DM/ha) and highest for FullET-weekly (28.9 t DM/ha) treatments. The remaining treatments did not differ in yield, producing 22.4±1.6 t DM/ha, but differed significantly from the Rain-fed and FullET-weekly treatments. Yield differences were associated with the rate of leaf area expansion and duration of critical LAI values (≥ 3.0 m2/m2), which were greater for FullET-weekly than for other treatments. Rain-fed and FullET-weekly treatments resulted in the highest and lowest WUE (81 versus 47 kg DM/ha/mm). The remaining treatments did not differ in WUE, averaging 67±3.6 kg DM/ha/mm. Our results show yield benefits from irrigation, with the best outcome from FullET-weekly given the soil type and weather conditions. However, under water restriction conditions, the HalfET-3weekly management is recommended over more frequent partial ET replacements because it would reduce irrigation costs without penalising yield
Plasma resonance at low magnetic fields as a probe of vortex line meandering in layered superconductors
We consider the magnetic field dependence of the plasma resonance frequency
in pristine and in irradiated BiSrCaCuO crystals near . At
low magnetic fields we relate linear in field corrections to the plasma
frequency to the average distance between the pancake vortices in the
neighboring layers (wandering length). We calculate the wandering length in the
case of thermal wiggling of vortex lines, taking into account both Josephson
and magnetic interlayer coupling of pancakes. Analyzing experimental data, we
found that (i) the wandering length becomes comparable with the London
penetration depth near T and (ii) at small melting fields ( G) the
wandering length does not change much at the melting transition. This shows
existence of the line liquid phase in this field range. We also found that
pinning by columnar defects affects weakly the field dependence of the plasma
resonance frequency near .Comment: RevTex, 4 pages, 2 PS figures, Submitted to Phys. Rev.
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