4,257 research outputs found
Association between body mass index and mental health among Scottish adult population: a cross-sectional study of 37,272 participants
<b>Background:</b> The evidence is conflicting as to whether body mass index (BMI) is associated with mental health and, if so, to what extent it varies by sex and age. We studied mental health across the full spectrum of BMI among the general population, and conducted subgroup analyses by sex and age.<p></p>
<b>Method:</b> We undertook a cross-sectional study of a representative sample of the Scottish adult population. The Scottish Health Survey provided data on mental health, measured by the General Health Questionnaire-12 (GHQ), BMI, demographic and life-style information. Good mental health was defined as a GHQ score <4, and poor mental health as a GHQ score ≥4. Logistic regression models were applied.
Results Of the 37 272 participants, 5739 (15.4%) had poor mental health. Overall, overweight participants had better mental health than the normal-weight group [adjusted odds ratio (OR) 0.93, 95% confidence interval (CI) 0.87–0.99, p = 0.049], and individuals who were underweight, class II or class III obese had poorer mental health (class III obese group: adjusted OR 1.26, 95% CI 1.05–1.51, p = 0.013). There were significant interactions of BMI with sex (p = 0.013) and with age (p < 0.001). Being overweight was associated with significantly better mental health in middle-aged men only. In contrast, being underweight at all ages or obese at a young age was associated with significantly poorer mental health in women only.<p></p>
<b>Conclusions:</b> The adverse associations between adiposity and mental health are specific to women. Underweight women and young women who are obese have poorer mental health. In contrast, middle-aged overweight men have better mental health.<p></p>
A New Halo Finding Method for N-Body Simulations
We have developed a new halo finding method, Physically Self-Bound (PSB)
group finding algorithm, which can efficiently identify halos located even at
crowded regions. This method combines two physical criteria such as the tidal
radius of a halo and the total energy of each particle to find member
particles. Two hierarchical meshes are used to increase the speed and the power
of halo identification in the parallel computing environments. First, a coarse
mesh with cell size equal to the mean particle separation is
used to obtain the density field over the whole simulation box. Mesh cells
having density contrast higher than a local cutoff threshold
are extracted and linked together for those adjacent to each other. This
produces local-cell groups. Second, a finer mesh is used to obtain density
field within each local-cell group and to identify halos. If a density shell
contains only one density peak, its particles are assigned to the density peak.
But in the case of a density shell surrounding at least two density peaks, we
use both the tidal radii of halo candidates enclosed by the shell and the total
energy criterion to find physically bound particles with respect to each halo.
Similar to DENMAX and HOP, the \hfind method can efficiently identify small
halos embedded in a large halo, while the FoF and the SO do not resolve such
small halos. We apply our new halo finding method to a 1-Giga particle
simulation of the CDM model and compare the resulting mass function
with those of previous studies. The abundance of physically self-bound halos is
larger at the low mass scale and smaller at the high mass scale than proposed
by the Jenkins et al. (2001) who used the FoF and SO methods. (abridged)Comment: 10 pages, 8 figs, submitted to Ap
Stable Umbral Chromospheric Structures
Aims. To understand the morphology of the chromosphere in sunspot umbra. We
investigate if the horizontal structures observed in the spectral core of the
Ca II H line are ephemeral visuals caused by the shock dynamics of more stable
structures, and examine their relationship with observables in the H-alpha
line. Methods. Filtergrams in the core of the Ca II H and H-alpha lines as
observed with the Swedish 1-m Solar Telescope are employed. We utilise a
technique that creates composite images and tracks the flash propagation
horizontally. Results. We find 0"15 wide horizontal structures, in all of the
three target sunspots, for every flash where the seeing was moderate to good.
Discrete dark structures are identified that are stable for at least two umbral
flashes, as well as systems of structures that live for up to 24 minutes. We
find cases of extremely extended structures with similar stability, with one
such structure showing an extent of 5". Some of these structures have a
correspondence in H-alpha but we were unable to find a one to one
correspondence for every occurrence. If the dark streaks are formed at the same
heights as umbral flashes then there are systems of structures with strong
departures from the vertical for all three analysed sunspots. Conclusions.
Long-lived Ca II H filamentary horizontal structures are a common and likely
ever-present feature in the umbra of sunspots. If the magnetic field in the
chromosphere of the umbra is indeed aligned with the structures, then the
present theoretical understanding of the typical umbra needs to be revisited.Comment: Accepted to Astronomy and Astrophysics. Online material (Fig3.mov and
Fig4.mov) will be available at A&
Two-stage fan. 2: Data and performance with redesigned second stage rotor uniform and distorted inlet flows
A two-stage fan with a first rotor tip speed of 1450 ft/sec (441.96 m/sec) and no inlet guide vanes was tested with uniform and distorted inlet flows, with a redesigned second rotor having a part span shroud to prevent flutter, with variable-stagger stators set in nominal positions, and without rotor casing treatment. The fan achieved a pressure ratio 2.8 at a corrected flow of 185.4 lbm/sec (84.0 kg/sec), an adiabatic efficiency of 85.0 percent, and a stall margin of 12 percent. The redesigned second rotor did not flutter. Tip radial distortion reduced the stall margin at intermediate speed, but had little effect on stall margin at high or low speeds. Hub radial distortion reduced the stall margin at design speed but increased stall margin at low speed. Circumferential distortion reduced stall pressure ratio and flow to give approximately the same stall lines with uniform inlet flow. Distortions were attenuated by the fan. For Vol. 1, see N74-11421
Metallicity and Physical Conditions in the Magellanic Bridge
We present a new analysis of the diffuse gas in the Magellanic Bridge (RA>3h)
based on HST/STIS E140M and FUSE spectra of 2 early-type stars lying within the
Bridge and a QSO behind it. We derive the column densities of HI (from
Ly\alpha), NI, OI, ArI, SiII, SII, and FeII of the gas in the Bridge. Using the
atomic species, we determine the first gas-phase metallicity of the Magellanic
Bridge, [Z/H]=-1.02+/-0.07 toward one sightline, and -1.7<[Z/H]<-0.9 toward the
other one, a factor 2 or more smaller than the present-day SMC metallicity.
Using the metallicity and N(HI), we show that the Bridge gas along our three
lines of sight is ~70-90% ionized, despite high HI columns, logN(HI)=19.6-20.1.
Possible sources for the ongoing ionization are certainly the hot stars within
the Bridge, hot gas (revealed by OVI absorption), and leaking photons from the
SMC and LMC. From the analysis of CII*, we deduce that the overall density of
the Bridge must be low (<0.03-0.1 cm^-3). We argue that our findings combined
with other recent observational results should motivate new models of the
evolution of the SMC-LMC-Galaxy system.Comment: Accepted for publication in the Ap
When a portion becomes a norm : exposure to a smaller vs. larger portion of food affects later food intake
Background:
Portion sizes in the food environment may communicate information about what constitutes a ‘normal’ amount of food to eat. Here we examined whether mere visual exposure to a smaller vs. larger portion size of snack food affects perceptions of how much a ‘normal’ sized portion is and how much people choose to eat of that food in future.
Methods:
Under the guise of a study on taste preference and personality, 104 female participants were randomly allocated to be exposed to either a smaller or larger portion size of snack food. Twenty-four hours later participants freely selected a portion of the snack food to consume and reported on their perception of what constituted a normal sized portion of the snack food.
Results:
Participants that were exposed to a smaller, as opposed to larger portion size subsequently believed that a normal portion of the snack food was smaller in size. Exposure to the smaller as opposed to the larger portion size also resulted in participants consuming less snack food the next day.
Conclusions:
Environmental exposure to smaller, as opposed to larger portion sizes of food may change perceptions of what constitutes a normal amount of food to eat and affect the amount of food people choose to eat in future
How should we ‘care’ for LGBT+ students within higher education?
This article draws on a recent U.K. research project about
lesbian, gay, bisexual and trans (LGBT+) perspectives on
university to examine the implications for pastoral care
and other service provision on campus. In a departure
from previous scholarship that has tended to understand
LGBT+ students as ‘vulnerable’ and/or needing ‘support’, it
argues that university spaces should be (re)framed in a way
that moves beyond (only) personal or individual ‘care’. The
article outlines some of the issues that LGBT+ students may
face under the following headings: Curriculum and course
content; Discrimination, prejudice and bullying; Facilities and service provision on campus; A continuum of experiences.
Following these, a final section draws some conclusions and
implications for practice in higher education
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