9,422 research outputs found
Participation in college sports and protection from sexual victimization
Some sociologists have argued that sport is a male-dominated institution and sexist culture in which female athletes experience various forms of discrimination, including sexual harassment from coaches and male athletes. Some research does indicate that female athletes suffer higher rates of sexual victimization from authority figures in sport than their nonathletic counterparts in education and the workplace. In contrast, researchers have also speculated that athletic participation can protect female athletes from sexual victimization through a variety of social-psychological mechanisms such as team membership, physical strength, and self-confidence. This paper reports on the first descriptive analysis to test the âsport protection hypothesisâ among both female and male athletes, using cross-tabulation secondary analyses of data from the National College Health Risk Behavior Survey, conducted in 1995 by the U.S. Centers for Disease Control and Prevention (N=4814). USA college students of traditional undergraduate age (aged 18-24) were included in the sample (N=2903). Some limited support for the protection hypothesis was found, and student athletes were significantly less likely to report sexual victimization during their late high school and early college years than their nonathletic counterparts. A gender gap in the pattern of sexual victimization also appeared between males and females across all student age groups, with females experiencing more sexual victimization than males. However, no significant gender gap was found among athletes. The results are discussed in relation to previous studies of campus athletes and to college prevention policy
A three dimensional model of the photosynthetic membranes of Ectothiorhodospira halochloris
The three dimensional organization of the complete photosynthetic apparatus of the extremely halophilic, bacteriochlorophyll b containing Ectothiorhodospira halochloris has been elaborated by several techniques of electron microscopy. Essentially all thylakoidal sacs are disc shaped and connected to the cytoplasmic membrane by small membraneous ldquobridgesrdquo. In sum, the lumina of all thylakoids (intrathylakoidal space) form one common periplasmic space. Thin sections confirm a paracrystalline arrangement of the photosynthetic complexes in situ. The ontogenic development of the photosynthetic apparatus is discussed based on a structural model derived from serial thin sections
Egg shape changes at the theropodâbird transition, and a morphometric study of amniote eggs
The eggs of amniotes exhibit a remarkable variety of shapes,
from spherical to elongate and from symmetrical to asymmetrical.
We examine eggshell geometry in a diverse sample of fossil
and living amniotes using geometric morphometrics and linear
measurements. Our goal is to quantify patterns of morphospace
occupation and shape variation in the eggs of recent through to
Mesozoic birds (neornithe plus non-neornithe avialans), as well
as in eggs attributed to non-avialan theropods. In most amniotes,
eggs show signiïŹcant deviation from sphericity, but departure
from symmetry around the equatorial axis is mostly conïŹned
to theropods and birds. Mesozoic bird eggs differ signiïŹcantly
from extant bird eggs, but extinct Cenozoic bird eggs do not. This
suggests that the range of egg shapes in extant birds had already
been attained in the Cenozoic. We conclude with a discussion
of possible biological factors imparting variation to egg shapes
during their formation in the oviduct
Advanced DC zonal marine power system protection
A new Active Impedance Estimation (AIE) based protection strategy which is suitable for utilization in a DC zonal marine power distribution system is presented. This method uses two triangular current "spikes" injections for system impedance estimation and protection when faults are detected. By comparing the estimated impedance with the pre-calibrated value, the fault location can be predicted and fault can be isolated without requiring communication between two injection units. Using coÂŹoperated double injections and line current measurement (directional fault detection), faults in the system with same impedance and different fault positions can be distinguished, located and isolated. The proposed method is validated using experimental test results derived from a 30kW, 400V, twin bus DC marine power system demonstrator. The experimental tests were applied to both faults during normal operation and faults that occur during system restoration
Stark effect in a wedge-shaped quantum box
The effect of an external applied electric field on the electronic ground
state energy of a quantum box with a geometry defined by a wedge is studied by
carrying out a variational calculation. This geometry could be used as an
approximation for a tip of a cantilever of an atomic force microscope. We study
theoretically the Stark effect as function of the parameters of the wedge: its
diameter, angular aperture and thickness; as well as function of the intensity
of the external electric field applied along the axis of the wedge in both
directions; pushing the carrier towards the wider or the narrower parts. A
confining electronic effect, which is sharper as the wedge dimensions are
smaller, is clearly observed for the first case. Besides, the sign of the Stark
shift changes when the angular aperture is changed from small angles to angles
theta>pi. For the opposite field, the electronic confinement for large
diameters is very small and it is also observed that the Stark shift is almost
independent with respect to the angular aperture.Comment: 23 pages, 9 figures, 1 tabl
Cross-linguistic Sharing of Morphological Awareness in Biliteracy Development: A Systematic Review and Meta-analysis of Correlation Coefficients
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordThis study examined the cross-linguistic sharing of morphological awareness (MA) in biliteracy
development. The analysis included 34 correlational studies with 40 independent samples (N =
4,056). Correlational coefficients were meta-analyzed, yielding four main findings: (1) the
correlation between first language (L1) and second language (L2) MA was small (r = 0.30). (2)
The interlingual correlations between L1 MA and L2 word decoding and between L1 MA and
L2 reading comprehension were both small (respective r = 0.35, 0.39). (3) The intralingual
correlations between L2 MA and L2 word decoding and between L2 MA and L2 reading
comprehension were both moderate (r = 0.45, 0.52). (4) MA measurement type and age were
significant moderators. Our review suggested that there is a need for future research to align the
definition and measurement of MA as a multifaceted construct, and pay equal attention to its
contributions to both word decoding and reading comprehension
Energy drink use, problem drinking and drinking motives in a diverse sample of Alaskan college students
Background. Recent research has identified the use of caffeinated energy drinks as a common, potentially risky behaviour among college students that is linked to alcohol misuse and consequences. Research also suggests that energy drink consumption is related to other risky behaviours such as tobacco use, marijuana use and risky sexual activity. Objective. This research sought to examine the associations between frequency of energy drink consumption and problematic alcohol use, alcohol-related consequences, symptoms of alcohol dependence and drinking motives in an ethnically diverse sample of college students in Alaska. We also sought to examine whether ethnic group moderated these associations in the present sample of White, Alaska Native/American Indian and other ethnic minority college students. Design. A paper-and-pencil self-report questionnaire was completed by a sample of 298 college students. Analysis of covariance (ANCOVA) was used to examine the effects of energy drink use, ethnic group and energy drink by ethnic group interactions on alcohol outcomes after controlling for variance attributed to gender, age and frequency of binge drinking. Results. Greater energy drink consumption was significantly associated with greater hazardous drinking, alcohol consequences, alcohol dependence symptoms, drinking for enhancement motives and drinking to cope. There were no main effects of ethnic group, and there were no significant energy drink by ethnic group interactions. Conclusion. These findings replicate those of other studies examining the associations between energy drink use and alcohol problems, but contrary to previous research we did not find ethnic minority status to be protective. It is possible that energy drink consumption may serve as a marker for other health risk behaviours among students of various ethnic groups
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