1,430 research outputs found
Why crime prevention strategies may be effective against both deliberate and impulsive burglars.
Not all those who commit burglary offenses do so for the same reasons – some are deliberate, planning their actions, while others are more impulsive. In new research on patterns of opportunism among burglars, Amber N. Sanders, Joseph B. Kuhns, and Kristie R. Blevins find that deliberate burglars are more motivated by money, while impulsive burglars were motivated by drugs and/or money. They suggest that burglars of both types may be dissuaded by crime prevention measures which might make their actions riskier
The Validity of a Novel Staged Exercise Test for Measuring Lactate Metabolism and Performance in Cyclists
Several types of lactate threshold (Tlac) protocols have been developed over the years to maximize accuracy and reliability while maintaining ease of measurement and application to training and performance. PURPOSE: The purpose of this study was to determine the validity of a novel staged maximal lactate steady state exercise test (sMLSS) in predicting the MLSS using the Lactate Plus® (Nova Biomedical, Waltham, MA) analyzer. METHODS: Blood lactate concentration (BLC) was measured in duplicate for all tests. Seven trained cyclists (20 miles per week) performed a V̇O2max test starting at 100W and increasing by 30W every three minutes until volitional fatigue. Lactate threshold was defined as the previous workload to a 2 mmol•L-1 increase in BLC. Next, the sMLSS test was performed starting at the Tlac workload, determined previously, then increasing 10W every 15 minutes for a total of three stages. BLC was measured every 3 minutes. MLSS was predicted by visual inspection and defined as \u3c 1.0 mmol•L-1 increase in the final 6 minutes of the stage. Finally, cyclists then performed two to six MLSS exercise tests, adjusting by 5W depending on lactate response, to validate the sMLSS. MLSS was determined at the maximal workload with \u3c 1 mmol•L-1 increase in BLC in the final 20 minutes. Dependent T-test and Pearson correlation coefficient was used to determine reliability between lactate trials. Bland-Altman plots, One-way ANOVA, and regression analyses were used to analyze differences between the types of exercise tests. RESULTS: There were no significant differences for duplicate BLC trials for all tests (p= 0.21; r=0.982). The sMLSS was significantly correlated with the MLSS workload and percentage of max workload (r = 0.997; p=0.001, r = 0.978, p=0.01), respectively. There was no bias noted between sMLSS and MLSS protocols for predicting lactate accumulation. CONCLUSION: This novel protocol was determined to be a valid and efficient means determining lactate performance in recreationally trained cyclists. The sMLSS was effective at reducing testing time from 12 days to 3 days
Spectral geometry, homogeneous spaces, and differential forms with finite Fourier series
Let G be a compact Lie group acting transitively on Riemannian manifolds M
and N. Let p be a G equivariant Riemannian submersion from M to N. We show that
a smooth differential form on N has finite Fourier series if and only if the
pull back has finite Fourier series on
Interaction of reed and acoustic resonator in clarinetlike systems
Sound emergence in clarinetlike instruments is investigated in terms of
instability of the static regime. Various models of reed-bore coupling are
considered, from the pioneering work of Wilson and Beavers ["Operating modes of
the clarinet", J. Acoust. Soc. Am. 56, 653--658 (1974)] to more recent modeling
including viscothermal bore losses and vena contracta at the reed inlet. The
pressure threshold above which these models may oscillate as well as the
frequency of oscillation at threshold are calculated. In addition to Wilson and
Beavers' previous conclusions concerning the role of the reed damping in the
selection of the register the instrument will play on, the influence of the
reed motion induced flow is also emphasized, particularly its effect on playing
frequencies, contributing to reduce discrepancies between Wilson and Beavers'
experimental results and theory, despite discrepancies still remain concerning
the pressure threshold. Finally, analytical approximations of the oscillating
solution based on Fourier series expansion are obtained in the vicinity of the
threshold of oscillation. This allows to emphasize the conditions which
determine the nature of the bifurcation (direct or inverse) through which the
note may emerge, with therefore important consequences on the musical playing
performances
Higher throughput quantification of neutralizing antibody to herpes simplex viruses
We report a rapid, higher throughput method for measuring neutralizing antibody to herpes simplex virus (HSV) in human sera. Clinical isolates and sera from the Herpevac Trial for Women were used in a colorimetric assay in which infection of tissue culture (lack of neutralization) was indicated by substrate metabolism by beta-galactosidase induced in the ELVIS cell line. The neutralization assay was optimized by addition of guinea pig complement, which particularly enhanced neutralizing antibody titers to HSV-2. Higher neutralizing antibody titers were also achieved using virus particles isolated from the supernatant of infected cells rather than lysate of infected cells as the source of virus. The effect of assay incubation time and incubation time with substrate were also optimized. We found that incubating with substrate until a standard optical density of 1.0 was reached permitted a better comparison among virus isolates, and achieved reliable measurement of neutralizing antibody activity. Interestingly, in contrast to results in the absence of complement, addition of complement allowed sera from HSV-2 gD-vaccinated subjects to neutralize HSV-1 and HSV-2 clinical and laboratory isolates with equal potency
Susceptibility Provision Enhances Effective De-escalation (SPEED): utilizing rapid phenotypic susceptibility testing in Gram-negative bloodstream infections and its potential clinical impact
Abstract
Objectives
We evaluated the performance and time to result for pathogen identification (ID) and antimicrobial susceptibility testing (AST) of the Accelerate Pheno™ system (AXDX) compared with standard of care (SOC) methods. We also assessed the hypothetical improvement in antibiotic utilization if AXDX had been implemented.
Methods
Clinical samples from patients with monomicrobial Gram-negative bacteraemia were tested and compared between AXDX and the SOC methods of the VERIGENE® and Bruker MALDI Biotyper® systems for ID and the VITEK® 2 system for AST. Additionally, charts were reviewed to calculate theoretical times to antibiotic de-escalation, escalation and active and optimal therapy
Results
ID mean time was 21 h for MALDI-TOF MS, 4.4 h for VERIGENE® and 3.7 h for AXDX. AST mean time was 35 h for VITEK® 2 and 9.0 h for AXDX. For ID, positive percentage agreement was 95.9% and negative percentage agreement was 99.9%. For AST, essential agreement was 94.5% and categorical agreement was 93.5%. If AXDX results had been available to inform patient care, 25% of patients could have been put on active therapy sooner, while 78% of patients who had therapy optimized during hospitalization could have had therapy optimized sooner. Additionally, AXDX could have reduced time to de-escalation (16 versus 31 h) and escalation (19 versus 31 h) compared with SOC.
Conclusions
By providing fast and reliable ID and AST results, AXDX has the potential to improve antimicrobial utilization and enhance antimicrobial stewardship
Multifrequency synthetic aperture radar antenna comparison study
Three multifrequency, dual polarization SAR antenna designs are reviewed. The SAR antenna design specifications were for a "straw man' SAR which would approximate the requirements for projected shuttle-based SAR's. Therefore, the physical dimensions were constrained to be compatible with the space shuttle. The electrical specifications were similar to those of SIR-A and SIR-B with the addition of dual polarization and the addition of C and X band operation. Early in the antenna design considerations, three candidate technologies emerged as having promise. They were: (1) microstrip patch planar array antennas, (2) slotted waveguide planar array antennas, and (3) open-ended waveguide planar array antennas
Thermal noise in interferometric gravitational wave detectors due to dielectric optical coatings
We report on thermal noise from the internal friction of dielectric coatings
made from alternating layers of Ta2O5 and SiO2 deposited on fused silica
substrates. We present calculations of the thermal noise in gravitational wave
interferometers due to optical coatings, when the material properties of the
coating are different from those of the substrate and the mechanical loss angle
in the coating is anisotropic. The loss angle in the coatings for strains
parallel to the substrate surface was determined from ringdown experiments. We
measured the mechanical quality factor of three fused silica samples with
coatings deposited on them. The loss angle of the coating material for strains
parallel to the coated surface was found to be (4.2 +- 0.3)*10^(-4) for
coatings deposited on commercially polished slides and (1.0 +- 0.3)*10^{-4} for
a coating deposited on a superpolished disk. Using these numbers, we estimate
the effect of coatings on thermal noise in the initial LIGO and advanced LIGO
interferometers. We also find that the corresponding prediction for thermal
noise in the 40 m LIGO prototype at Caltech is consistent with the noise data.
These results are complemented by results for a different type of coating,
presented in a companion paper.Comment: Submitted to LSC (internal) review Sept. 20, 2001. To be submitted to
Phys. Lett.
The effect of spacing on the vortex-induced vibrations of two tandem flexible cylinders
Vortex-induced vibrations (VIV) of two flexible cylinders arranged in tandem are studied using a two-way fluidstructure interaction (FSI) method with different spacing ratios (Sx/D) at Reynolds number Re = 500 using a twoway fluid-structure interaction (FSI) method. The main objective of this study is to investigate the effect of spacing on the hydrodynamic interactions and the VIV responses of these cylinders. The responses of the two flexible cylinders are found to be similar to the classical VIV responses at small Sx/D. Once Sx/D is large enough for the vortices to become detached from the upstream cylinder, the response of the upstream cylinder is similar to the typical VIV response whereas the downstream cylinder undergoes wake-induced vibration (WIV). The characteristics of the response of the downstream cylinder in the present study are similar to those of the first two response regimes classified by previous researchers. The third regime is not observed for the flexible downstream cylinder with both ends fixed. The two changes in the phase relation between the cross-flow displacements of the two tandem flexible cylinders are discovered to be linked with the initial-upper branch transition and the upperlower branch transition, respectively. The correlation lengths of the two flexible cylinders decrease significantly in the transition range between the upper and lower branches. Three modes of vortex shedding (2S, P + S and 2P) have been identified in the present study. The upper-branch 2P mode is found to be associated with largeamplitude vibration of the upstream cylinder and the P + S mode is observed to be related to large-amplitude vibration of the downstream cylinder for Sx/D = 3.5 and 5. On the other hand, the lower-branch 2P mode leads to small-amplitude vibration of the downstream cylinder in the post-lock-in range at Sx/D = 2.5. The relative phase shifts of the sectional lift coefficients on different spanwise cross sections can be attributed to the variation of the vortex shedding flow along the flexible cylinders, and these phase shifts result in poor phasing between the forces and the displacements which is related to the decrease of the correlation lengths
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