8,757 research outputs found
A signal analysis investigation of brainstem auditory evoked potentials
Imperial Users onl
A circumpolar perspective on fluvial sediment flux to the Arctic ocean
Quantification of sediment fluxes from rivers is fundamental to understanding landâocean linkages in the Arctic. Numerous publications have focused on this subject over the past century, yet assessments of temporal trends are scarce and consensus on contemporary fluxes is lacking. Published estimates vary widely, but often provide little accessory information needed to interpret the differences. We present a panâarctic synthesis of sediment flux from 19 arctic rivers, primarily focusing on contributions from the eight largest ones. For this synthesis, historical records and recent unpublished data were compiled from Russian, Canadian, and United States sources. Evaluation of these data revealed no longâterm trends in sediment flux, but did show stepwise changes in the historical records of two of the rivers. In some cases, old values that do not reflect contemporary fluxes are still being reported, while in other cases, typographical errors have been propagated into the recent literature. Most of the discrepancy among published estimates, however, can be explained by differences in years of records examined and gauging stations used. Variations in sediment flux from year to year in arctic rivers are large, so estimates based on relatively few years can differ substantially. To determine best contemporary estimates of sediment flux for the eight largest arctic rivers, we used a combination of newly available data, historical records, and literature values. These estimates contribute to our understanding of carbon, nutrient, and contaminant transport to the Arctic Ocean and provide a baseline for detecting future anthropogenic or natural change in the Arctic
Early Sport Specialization: Overuse Injury and Burnout
There are an increasing number of opportunities for todayâs youth to participate in year-round sport organizations that promote early sport specialization before the age of fifteen. Early sport specialization is linked to a higher rate of overuse injury of frequently used muscle groups. The physical, mental, and psychological demands of early sport specialization increase likelihood of burnout and cessation of sport participation. Early sport generalization allows physiological and psychological rest and recovery in youth athletes that lead to decreased injury rates and less burnout with more individuals continuing to participate in competitive sports throughout the collegiate years. The purpose of this research was to determine what effect, if any, early sport specialization in youth has on rate of overuse injury and burnout in NCAA Division III athletes at a small, private University. A 12-question, retrospective, written survey classified each participant as an early sport specialist or early sport generalist and gathered information on frequency of overuse injury and development of burnout during the high school and college competitive sport years. Statistical analysis indicated early sport generalists were more likely to participate in competitive collegiate athletics at the NCAA Division III Institution analyzed in this study (71.8%). Early sport specialists were more likely to experience burnout (P = 0.088) and may be more likely to develop overuse injury during the high school years (P = 0.254) but not the college years (P=0.385). It is unknown if early sport specialists are more likely to develop a greater number of overuse injuries throughout their competitive sport career than early sport generalists. Young athletes are encouraged to participate in multiple competitive sports but the results of this research were not statistically significant and further research needs to be done to support these conclusions
Stereotyping Gender Roles: Children\u27s Commercial Advertisement
Heteronormativity gives the individual in our society a binary optional choice: the first choice being the socially accepted ânormâ that follows the heteronormative binary, and the second being the socially disfavored choice of being deemed âabnormalâ if one chooses to go against this heteronormative binary. In return, we as a socially constructed society then deem the binary option of the ânormâ as the culturally preferred âgoodâ choice, while at the same time deem the other binary option of the âabnormalâ as the socially constructed âbadâ choice. This occurs both intentionally and unintentionally. The purpose behind my area of focus is to identify that the binary stereotyping of heteronormative gender roles in childrenâs commercial advertisement is resulting in young children having an essentialized heteronormative embedded ideology. With childrenâs commercial advertisements exclusively representing the heteronormative non-intersectional gender role narratives, this identity exclusion is leading children to reject any form of intersectional identity that doesnât fit in the heteronormative binary bracket, as a subordinate socially ostracized form of gender and or sex identity for a child not to follow
Arm cavity resonant sideband control for laser interferometric gravitational wave detectors
We present a new optical control scheme for a laser interferometric gravitational wave detector that has a high degree of tolerance to interferometer spatial distortions and noise on the input light. The scheme involves resonating the rf sidebands in an interferometer arm cavity
Atom lithography using MRI-type feature placement
We demonstrate the use of frequency-encoded light masks in neutral atom
lithography. We demonstrate that multiple features can be patterned across a
monotonic potential gradient. Features as narrow as 0.9 microns are fabricated
on silicon substrates with a metastable argon beam. Internal state manipulation
with such a mask enables continuously adjustable feature positions and feature
densities not limited by the optical wavelength, unlike previous light masks.Comment: 4 pages, 4 figure
Control and tuning of a suspended Fabry-Perot cavity using digitally-enhanced heterodyne interferometry
We present the first demonstration of real-time closed-loop control and
deterministic tuning of an independently suspended Fabry-Perot optical cavity
using digitally-enhanced heterodyne interferometry, realising a peak
sensitivity of 10 pm over the 10-1000 Hz frequency
band. The methods presented are readily extensible to multiple coupled
cavities. As such, we anticipate that refinements of this technique may find
application in future interferometric gravitational-wave detectors
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