270 research outputs found
Adverse Consequences to Assisting Victims of Campus Violence: Initial Investigations Among College Students
Despite growing interest in the use of bystander education programs to address the problems of sexual and relationship violence on college campuses, little knowledge exists on adverse consequences experienced by students intervening as a bystander. The current study examined the prevalence and correlates of adverse consequences of bystander intervention in two samples of first-year college students. In Study 1, 281 students completed a measure of negative consequences experienced when acting as a bystander to help someone at risk of sexual assault, relationship abuse, or stalking. Efficacy for bystander behavior was also assessed. Approximately one third of the students (97/281) reported having tried to help someone who had been at risk of violence during the previous academic year. Of these, approximately 17% (16/97) reported experiencing a negative consequence from having tried to help. Experiencing negative consequences was associated with lower levels of bystander efficacy. In Study 2, conducted at a different university, 299 students completed measures of negative consequences resulting from intervening as a bystander and efficacy for bystander behavior. Students also participated in virtual-reality simulations that provided opportunities to intervene as a bystander. Again, approximately one third of the students (99/299) reported having tried to help someone at risk of violence. Of these, 20% (20/99) reported experiencing a negative consequence. Two of the adverse consequences (physically hurt, got into trouble) were negatively associated with bystander efficacy and observed effectiveness of bystander behavior in the virtual simulations. Results of exploratory analyses suggest that training in bystander intervention might reduce the likelihood of experiencing adverse consequences
Searching for compact objects in the single-lined spectroscopic binaries of the young Galactic cluster NGC 6231
Recent evolutionary computations predict that a few percent of massive OB
stars in binary systems should have a dormant BH companion. Despite several
reported X-ray quiet OB+BH systems over the last couple of years, finding them
with certainty remains challenging. These have great importance as they can be
gravitational wave (GW) source progenitors, and are landmark systems in
constraining supernova kick physics. This work aims to characterise the hidden
companions to the single-lined spectroscopic binaries (SB1s) in the B star
population of the young open Galactic cluster NGC 6231 to find candidate
systems for harbouring compact object companions. With the orbital solutions
for each SB1 previously constrained, we applied Fourier spectral disentangling
to multi-epoch optical VLT/FLAMES spectra of each target to extract a potential
signature of a faint companion, and to identify newly disentangled double-lined
spectroscopic binaries (SB2s). For targets where the disentangling does not
reveal any signature of a stellar companion, we performed atmospheric and
evolutionary modelling on the primary to obtain constraints on the unseen
companion. Seven newly classified SB2 systems with mass ratios down to near 0.1
were identified. From the remaining targets, for which no faint companion could
be extracted from the spectra, four are found to have companion masses in the
predicted mass ranges of neutron stars (NSes) and BHes. Two of these have
companion masses between 1 and 3.5 , making them potential hosts of
NSes (or lower mass main sequence stars). The other two are between 2.5 to 8
and 1.6 and 26 , respectively, and so are identified as
candidates for harbouring BH companions. However, unambiguous identification of
these systems as X-ray quiet compact object harbouring binaries requires follow
up observations.Comment: Submitted to A&
Women, know your limits: Cultural sexism in academia
Despite the considerable advances of the feminist movement across Western societies, in Universities women are less likely to be promoted, or paid as much as their male colleagues, or even get jobs in the first place. One way in which we can start to reflect on why this might be the case is through hearing the experiences of women academics themselves. Using feminist methodology, this article attempts to unpack and explore just some examples of
âcultural sexismâ which characterise the working lives of many women in British academia.This article uses qualitative methods to describe and make sense of just some of those experiences. In so doing, the argument is also made that the activity of academia is profoundly gendered and this explicit acknowledgement may contribute to our
understanding of the under-representation of women in senior positions
Tango of celestial dancers: A sample of detached eclipsing binary systems containing g-mode pulsating components. A case study of KIC9850387
Context. Eclipsing binary systems with components that pulsate in gravity modes (g modes) allow for simultaneous and independent constraints of the chemical mixing profiles of stars. The high precision of the dynamical masses and radii as well as the imposition of identical initial chemical compositions and equivalent ages provide strong constraints during the modelling of g-mode period-spacing patterns.
Aims. We aim to assemble a sample of g-mode pulsators in detached eclipsing binaries with the purpose of finding good candidates for future evolutionary and asteroseismic modelling. In addition, we present a case study of the eclipsing binary KIC9850387, identified as our most promising candidate, and detail the results of the observational spectroscopic, photometric, and asteroseismic analysis of the system.
Methods. We selected all of the detached eclipsing binaries in the Kepler eclipsing binary catalogue with Kepler Input Catalogue (KIC) temperatures between 6000 K and 10 000 K, and performed a visual inspection to determine the presence and density of g modes, and the presence of g-mode period-spacing patterns in their frequency spectra. We then characterised our sample based on their g-mode pulsational parameters and binary and atmospheric parameters. A spectroscopic follow-up of our most promising candidate was then performed, and the orbital elements of the system were extracted. We then performed spectral disentangling followed by atmospheric modelling and abundance analysis for the primary star. We utilised an iterative approach to simultaneously optimise the pulsational and eclipse models, and subsequently performed an analysis of the pressure- (p-) and g-mode pulsational frequencies.
Results. We compiled a sample of 93 Kepler eclipsing binary stars with g-mode pulsating components and identified clear g-mode period-spacing patterns in the frequency spectra of seven of these systems. We also identified 11 systems that contained hybrid p- and g-mode pulsators. We found that the g-mode pulsational parameters and the binary and atmospheric parameters of our sample are weakly correlated at best, as expected for detached main-sequence binaries. We find that the eclipsing binary KIC9850387 is a double-lined spectroscopic binary in a near-circular orbit with a hybrid p- and g-mode pulsating primary with M_p = 1.66_(â0.01)^(+0.01) Mâ and R_p = 2.154_(â0.004)^(+0.002) Râ, and a solar-like secondary with M_s = 1.062_(â0.005)^(+0.003) Mâ and R_s = 1.081_(â0.002)^(+0.003) Râ. We find ââ=â1 and ââ=â2 period-spacing patterns in the frequency spectrum of KIC9850387 spanning more than ten radial orders each, which will allow for stringent constraints of stellar structure during future asteroseismic modelling
Perceptual, metabolic, and neuromuscular responses to 10, 20, and 30% velocity loss thresholds during the barbell back-squat.
Introduction: This study compared the effects of 10, 20, and 30% velocity loss (VL) thresholds on differential ratings of perceived exertion (dRPE), lactate, and countermovement jump height (CMJ) during, immediately post-, and 24 hours post-five sets of the barbell back-squat.
Methods: In a randomised-crossover design, 15 resistance-trained males completed five sets of the back-squat with an initial mean concentric velocity of 0.70±0.01 m·s-1 and a set termination threshold of either 10% (0.63m·s-1), 20% (0.56m·s-1), or 30% (0.49m·s-1) VL. External load was manipulated throughout each session to ensure the first repetition of sets 2-5 was 0.70±0.06 m·s-1. Participants provided fingertip lactate at the completion of each set, while CMJ was collected pre-, post-, and 24 hours post-exercise. dRPE for the legs and lungs was provided at the completion of the 5th set. Three minutes rest was provided between sets, while barbell velocity was assessed during exercise to guide set termination.
Results: Peak lactate responses in the 30% condition were likely (effect size ±90confidence interval: 1.45±2.29) and almost certainly (4.56±1.66) greater when compared to the 20% and 10%, respectively. In the 10, 20, and 30% conditions, CMJ height was reduced by 11.3% (±2.4), 14.0% (±3.3), and 20.0% (±3.4), immediately post-exercise. Additionally, dRPE (mean (±SD)) of the legs and lungs were, 10%: 27±12 and 20±9; 20%: 53±16 and 50±17; and 30%: 65±18 and 65±17. At 24 hours post-training, CMJ performance was, 10%: +0.7% (±2.4); 20%: -0.6% (±2.0); and 30%: -2.7% (±2.7).
Conclusion: Different VL thresholds during the back-squat cause varying perceptual, metabolic, and neuromuscular responses. The use of 30% VL thresholds can cause substantially greater metabolic responses and potentially attenuate neuromuscular function at 24 hours post-training. Alternatively, a 10% VL can mitigate perceived exertion and changes in metabolic responses. These findings should be considered during the planning of velocity-based resistance training programmes
A calibration point for stellar evolution from massive star asteroseismology
Massive stars are progenitors of supernovae, neutron stars and black holes.
During the hydrogen-core burning phase their convective cores are the prime
drivers of their evolution, but inferences of core masses are subject to
unconstrained boundary mixing processes. Moreover, uncalibrated transport
mechanisms can lead to strong envelope mixing and differential radial rotation.
Ascertaining the efficiency of the transport mechanisms is challenging because
of a lack of observational constraints. Here we deduce the convective core mass
and robustly demonstrate non-rigid radial rotation in a supernova progenitor,
the solar-mass hydrogen-burning star HD 192575, using
asteroseismology, TESS photometry, high-resolution spectroscopy, and Gaia
astrometry. We infer a convective core mass (
solar masses), and find the core to be rotating between 1.4 and 6.3 times
faster than the stellar envelope depending on the location of the rotational
shear layer. Our results deliver a robust inferred core mass of a massive star
using asteroseismology from space-based photometry. HD 192575 is a unique
anchor point for studying interior rotation and mixing processes, and thus also
angular momentum transport mechanisms inside massive stars.Comment: 41 pages, 5 figures, 1 table. Version comment: updated erroneous
affiliatio
The Effects of 10%, 20%, and 30% Velocity Loss Thresholds on Kinetic, Kinematic, and Repetition Characteristics During the Barbell Back Squat.
PURPOSE: Prescribing resistance training using velocity loss thresholds can enhance exercise quality by mitigating neuromuscular fatigue. Since little is known regarding performance during these protocols, we aimed to assess the effects of 10%, 20%, and 30% velocity loss thresholds on kinetic, kinematic, and repetition characteristics in the free-weight back squat. METHODS: Using a randomised crossover design, sixteen resistance-trained men were recruited to complete five sets of the barbell back squat. Lifting load corresponded to a mean concentric velocity (MV) of ~0.70 m·s-1 (115 ±22kg). Repetitions were performed until a 10%, 20% or 30% MV loss was attained. RESULTS: Set MV and power output were substantially higher in the 10% protocol (0.66 m.s-1 & 1341 W, respectively), followed by the 20% (0.62 & 1246) and 30% protocols (0.59 & 1179). There were no substantial changes in MV (-0.01- -0.02) or power output (-14- -55 W) across the five sets for all protocols and individual differences in these changes were typically trivial to small. Mean set repetitions were substantially higher in the 30% protocol (7.8), followed by the 20% (6.4) and 10% protocols (4.2). There were small to moderate reductions in repetitions across the five sets during all protocols (-39%, -31%, -19%, respectively) and individual differences in these changes were small to very large. CONCLUSIONS: Velocity training prescription maintains kinetic and kinematic output across multiple sets of the back squat, with repetition ranges being highly variable. Our findings therefore challenge traditional resistance training paradigms (repetition-based) and add support to a velocity-based approach
The young massive SMC cluster NGC 330 seen by MUSE III. Stellar parameters and rotational velocities
The origin of initial rotation rates of stars, and how a star's surface
rotational velocity changes during the evolution, either by internal angular
momentum transport or due to interactions with a binary companion, remain open
questions in stellar astrophysics. Here, we aim to derive the physical
parameters and study the distribution of (projected) rotational velocities of
B-type stars in the 35 Myr-old, massive cluster NGC 330 in the Small Magellanic
Cloud. NGC 330 is in an age range where the number of post-interaction binaries
is predicted to be high near the cluster turnoff (TO). We develop a
simultaneous photometric and spectroscopic grid-fitting method adjusting
atmosphere models on multi-band Hubble Space Telescope photometry and Multi
Unit Spectroscopic Explorer spectroscopy. This allows us to homogeneously
constrain the physical parameters of over 250 B and Be stars, brighter than
mF814W = 18.8 mag. The rotational velocities of Be stars in NGC 330 are
significantly higher than the ones of B stars. The rotational velocities vary
as a function of the star's position in the color-magnitude diagram,
qualitatively following predictions of binary population synthesis. A
comparison to younger clusters shows that stars in NGC 330 rotate more rapidly
on average. The rotational velocities of the 35 Myr old population in NGC 330
quantitatively agree with predictions for a stellar population that underwent
significant binary interactions: the bulk of the B stars could be single stars
or primaries in pre-interaction binaries. The rapidly spinning Be stars could
be mass and angular momentum gainers in previous interactions, while those Be
stars close to the TO may be spun-up single stars. The slowly rotating,
apparently single stars above the TO could be merger products. The different
vsini-characteristics of NGC 330 compared to younger populations can be
understood in this framework.Comment: 18 pages (incl. appendix), 15 figures, 3 tables, accepted for
publication in A&
Investigating the effect of child maltreatment on early adolescent peer-on-peer sexual aggression: testing a multiple mediator model in a non-incarcerated sample of Danish adolescents
Objective: The aim of the present study was to investigate the relationship between child maltreatment and severe early adolescent peer-on-peer sexual aggression, using a multiple mediator model. Methods: The study comprised 330 male Grade 9 students with a mean age of 14.9 years (SD=0.5). Results: Estimates from the mediation model indicated significant indirect effects of child physical abuse on sexual aggression via peer influence and insecure-hostile masculinity. No significant total effect of child sexual abuse and child neglect on sexual aggression was found. Conclusions: Findings of the present study identify risk factors that are potentially changeable and therefore of value in informing the design of prevention programs aiming at early adolescent peer-on-peer sexual aggression in at-risk youth
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