6,154 research outputs found
Stress Urinary Incontinence in Female Athletes
Objective: The purpose of this study is to educate allied health professionals and female athletes of the anatomy of the pelvic floor, and the pathology, etiology, and prevalence of stress urinary incontinence in female athletes. Background: Urinary incontinence is not a life-threatening or dangerous condition, but it is socially embarrassing, may cause the individual to remove herself from social situations, and decrease quality of life. While typically associated with parous women who had vaginal delivery, research has shown prevalence of the condition in physically active women of all ages. Stress urinary incontinence has shown to lead to withdrawal from participation in high-impact activities such as gymnastics, aerobics, and running. It may be considered a barrier for life-long athletics participation in women. Description: An in-depth introduction to the cause and origin of stress urinary incontinence including review of the female pelvic floor anatomy and prevalence of stress urinary incontinence in the female athletic population. Clinical Advantages: Athletic trainers and other allied health professionals will develop an understanding of the multiple mechanisms that cause stress urinary incontinence. Clinician competency of the dynamics and mechanism of urinary incontinence prepares the individual to learn diagnostics, prevention, pharmacological intervention, and treatment of this pathology
Olfactory experience shapes the evaluation of odour similarity in ants - a behavioural and computational analysis
Perceptual similarity between stimuli is often assessed via generalisation, the response to stimuli that are similar to the one which was previously conditioned. Although conditioning procedures are variable, studies on how this variation may affect perceptual similarity remain scarce. Here, we use a combination of behavioural and computational analyses to investigate the influence of olfactory conditioning procedures on odour generalisation in ants. Insects were trained following either absolute conditioning, in which a single odour (an aldehyde) was rewarded with sucrose, or differential conditioning, in which one odour (the same aldehyde) was similarly rewarded and another odour (an aldehyde differing in carbon-chain length) was punished with quinine. The response to the trained odours and generalisation to other aldehydes were assessed. We show that olfactory similarity, rather than being immutable, varies with the conditioning procedure. Compared to absolute conditioning, differential conditioning enhances olfactory discrimination. This improvement is best described by a multiplicative interaction between two independent processes, the excitatory and inhibitory generalisation gradients induced by the rewarded and the punished odour, respectively. We show that olfactory similarity is dramatically shaped by an individualâs perceptual experience and suggest a new hypothesis for the nature of stimulus interactions underlying experience-dependent changes in perceptual similarity
Fine-time energetic electron behavior observed by Cluster/RAPID in the magnetotail associated with X-line formation and subsequent current disruption
Energetic electrons with 90deg pitch angle have been observed in the magnetotail at ~19 <i>R<sub>E</sub></i> near local midnight during the recovery phase of a substorm event on 27 August 2001 (Baker et al., 2002). Based on auroral images Baker et al. (2002) placed the substorm expansion phase between ~04:06:16 and ~04:08:19&nbsp;UT. The electron enhancements perpendicular to the ambient magnetic field occurred while the Cluster spacecraft were on closed field lines in the central plasma sheet approaching the neutral sheet. Magnetic field and energetic particle measurements have been employed from a number of satellites, in order to determine the source and the subsequent appearance of these electrons at the Cluster location. It is found that ~7.5 min after an X-line formation observed by Cluster (Baker et al., 2002) a current disruption event took place inside geosynchronous orbit and subsequently expanded both in local time and tailward, giving rise to field-aligned currents and the formation of a current wedge. A synthesis of tail reconnection and the cross-tail current disruption scenario is proposed for the substorm global initiation process: When a fast flow with northward magnetic field, produced by magnetic reconnection in the midtail, abruptly decelerates at the inner edge of the plasma sheet, it compresses the plasma populations earthward of the front, altering dynamically the B<sub>z</sub> magnetic component in the current sheet. This provides the necessary and sufficient conditions for the kinetic cross-field streaming/current (KCSI/CFCI) instability (Lui et al., 1990, 1991) to initiate. As soon as the ionospheric conductance increases over a threshold level, the auroral electrojet is greatly intensified (see Fig. 2 in Baker et al., 2002), which leads to the formation of the substorm current wedge and dipolarization of the magnetic field. This substorm scenario combines the near-Earth neutral line and the current disruption for the initiation of substorms, at least during steady southward IMF. One can conclude the following: The observations suggest that the anisotropic electron increases observed by Cluster are not related to an acceleration mechanism associated with the X-line formation in the midtail, but rather these particles are generated in the dusk magnetospheric sector due to the longitudinal and tailward expansion of a current disruption region and subsequently observed at the Cluster location with no apparent energy dispersion.<br><br> <b>Keywords.</b> Magnetospheric physics (Magnetotail; Plasma convection; Storms and substorms
Redistribution of Adhesive Forces through Src/FAK Drives Contact Inhibition of Locomotion in Neural Crest
Contact inhibition of locomotion is defined as the behavior of cells to cease migrating in their former direction after colliding with another cell. It has been implicated in multiple developmental processes and its absence has been linked to cancer invasion. Cellular forces are thought to govern this process; however, the exact role of traction through cell-matrix adhesions and tension through cell-cell adhesions during contact inhibition of locomotion remains unknown. Here we use neural crest cells to address this and show that cell-matrix adhesions are rapidly disassembled at the contact between two cells upon collision. This disassembly is dependent upon the formation of N-cadherin-based cell-cell adhesions and driven by Src and FAK activity. We demonstrate that the loss of cell-matrix adhesions near the contact leads to a buildup of tension across the cell-cell contact, a step that is essential to drive cell-cell separation after collision
An ultra-sensitive pulsed balanced homodyne detector: Application to time-domain quantum measurements
A pulsed balanced homodyne detector has been developed for precise
measurements of electric field quadratures of pulsed optical quantum states. A
high level of common mode suppression (> 85 dB) and low electronic noise (730
electrons per pulse) provide a signal to noise ratio of 14 dB for the
measurement of the quantum noise of individual pulses. Measurements at
repetition rates up to 1 MHz are possible. As a test, quantum tomography of the
coherent state is performed and the Wigner function and the density matrix are
reconstructed with a 99.5% fidelity. The detection system can also be used for
ultrasensitive balanced detection in cw mode, e.g. for weak absorption
measurements.Comment: 3 pages, submitted to Optics Letter
Model- and calibration-independent test of cosmic acceleration
We present a calibration-independent test of the accelerated expansion of the
universe using supernova type Ia data. The test is also model-independent in
the sense that no assumptions about the content of the universe or about the
parameterization of the deceleration parameter are made and that it does not
assume any dynamical equations of motion. Yet, the test assumes the universe
and the distribution of supernovae to be statistically homogeneous and
isotropic. A significant reduction of systematic effects, as compared to our
previous, calibration-dependent test, is achieved. Accelerated expansion is
detected at significant level (4.3 sigma in the 2007 Gold sample, 7.2 sigma in
the 2008 Union sample) if the universe is spatially flat. This result depends,
however, crucially on supernovae with a redshift smaller than 0.1, for which
the assumption of statistical isotropy and homogeneity is less well
established.Comment: 13 pages, 2 figures, major change
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