811 research outputs found
Promotion of physical activity in rural, remote and northern settings: a Canadian call to action
Introduction: The lack of policy, practice and research action on physical activity and features of the physical (built and natural) environments in rural, remote and northern settings is a significant threat to population health equity in Canada. This paper presents a synthesis of current evidence on the promotion of physical activity in non-urban settings, outcomes from a national priority-setting meeting, and a preliminary call to action to support the implementation and success of population-level initiatives targeting physical activity in non-urban settings.
Methods: We conducted a âsynopses of synthesesâ scoping review to explore current evidence on physical activity promotion in rural, remote, northern and natural settings. Next, we facilitated a collaborative priority-setting conference with 28 Canadian experts from policy, research and practice arenas to develop a set of priorities on physical activity in rural, remote and northern communities. These priorities informed the development of a preliminary Canadian call to action.
Results: We identified a limited number of reviews that focused on physical activity and the built environment in rural, remote and northern communities. At the priority-setting conference, participants representing rural, remote and northern settings identified top priorities for policy, practice and research action to begin to address the gaps and issues noted in the literature. These priorities include self-identifying priorities at the community level; compiling experiences; establishing consistency in research definitions and methods; and developing mentorship opportunities.
Conclusion: Coordinated action across policy, practice and research domains will be essential to the success of the recommendations presented in this call to action
Factors that influence excessive gestational weight gain: Moving beyond assessment and counselling
One in four Canadian adults is obese, and more women are entering pregnancy with a higher body mass index (BMI) than in the past. Pregnant women who are overweight or obese have a higher risk of pregnancy-related complications than women of normal weight. Gestational weight gain (GWG) is also associated with childhood obesity. Although the factors influencing weight gain during pregnancy are multifaceted, little is known about the social inequality of GWG. This review will address some of the socioeconomic factors and maternal characteristics influencing weight gain and the impact that excessive GWG has on health outcomes such as post-partum weight retention. The effects of an overweight or obese pre-pregnancy BMI on GWG and neonatal outcomes will also be addressed. The timing of weight gain is also important, as recommendations now include trimester-specific guidelines. While not conclusive, preliminary evidence suggests that excessive weight gain during the first trimester is most detrimental
Global asteroseismic properties of solar-like oscillations observed by Kepler : A comparison of complementary analysis methods
We present the asteroseismic analysis of 1948 F-, G- and K-type main-sequence
and subgiant stars observed by the NASA {\em Kepler Mission}. We detect and
characterise solar-like oscillations in 642 of these stars. This represents the
largest cohort of main-sequence and subgiant solar-like oscillators observed to
date. The photometric observations are analysed using the methods developed by
nine independent research teams. The results are combined to validate the
determined global asteroseismic parameters and calculate the relative precision
by which the parameters can be obtained. We correlate the relative number of
detected solar-like oscillators with stellar parameters from the {\em Kepler
Input Catalog} and find a deficiency for stars with effective temperatures in
the range \,K and a drop-off in
detected oscillations in stars approaching the red edge of the classical
instability strip. We compare the power-law relationships between the frequency
of peak power, , the mean large frequency separation,
, and the maximum mode amplitude, , and show that
there are significant method-dependent differences in the results obtained.
This illustrates the need for multiple complementary analysis methods to be
used to assess the robustness and reproducibility of results derived from
global asteroseismic parameters.Comment: 14 pages, 9 figures, accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Hubble Space Telescope Observations of an Outer Field in Omega Centauri: A Definitive Helium Abundance
We revisit the problem of the split main sequence (MS) of the globular
cluster omega Centauri, and report the results of two-epoch Hubble Space
Telescope observations of an outer field, for which proper motions give us a
pure sample of cluster members, and an improved separation of the two branches
of the main sequence. Using a new set of stellar models covering a grid of
values of helium and metallicity, we find that the best possible estimate of
the helium abundance of the bluer branch of the MS is Y = 0.39 +/- 0.02. For
the cluster center we apply new techniques to old observations: we use indices
of photometric quality to select a high-quality sample of stars, which we also
correct for differential reddening. We then superpose the color-magnitude
diagram of the outer field on that of the cluster center, and suggest a
connection of the bluer branch of the MS with one of the more prominent among
the many sequences in the subgiant region. We also report a group of undoubted
cluster members that are well to the red of the lower MS.Comment: 26 pages, 10 figures (4 in low resolution. AJ accepted on March 21,
201
Stress Dependence of Exciton Relaxation Processes in Cu2O
A comprehensive study of the exciton relaxation processes in Cu2O has led to
some surprises. We find that the ortho-para conversion rate becomes slower at
high stress, and that the Auger nonradiative recombination rate increases with
stress, with apparently no Auger recombination at zero stress. These results
have important consequences for the pursuit of Bose-Einstein condensation of
excitons in a harmonic potential.Comment: 10 figures, 1 tabl
Solar-like oscillations in cluster stars
We present a brief overview of the history of attempts to obtain a clear
detection of solar-like oscillations in cluster stars, and discuss the results
on the first clear detection, which was made by the Kepler Asteroseismic
Science Consortium (KASC) Working Group 2.Comment: 4 pages, 7 figures, accepted by Astronomische Nachrichte
Verification of the Kepler Input Catalog from Asteroseismology of Solar-type Stars
We calculate precise stellar radii and surface gravities from the
asteroseismic analysis of over 500 solar-type pulsating stars observed by the
Kepler space telescope. These physical stellar properties are compared with
those given in the Kepler Input Catalog (KIC), determined from ground-based
multi-color photometry. For the stars in our sample, we find general agreement
but we detect an average overestimation bias of 0.23 dex in the KIC
determination of log (g) for stars with log (g)_KIC > 4.0 dex, and a resultant
underestimation bias of up to 50% in the KIC radii estimates for stars with
R_KIC < 2 R sun. Part of the difference may arise from selection bias in the
asteroseismic sample; nevertheless, this result implies there may be fewer
stars characterized in the KIC with R ~ 1 R sun than is suggested by the
physical properties in the KIC. Furthermore, if the radius estimates are taken
from the KIC for these affected stars and then used to calculate the size of
transiting planets, a similar underestimation bias may be applied to the
planetary radii.Comment: Published in The Astrophysical Journal Letter
Noise Sources in Photometry and Radial Velocities
The quest for Earth-like, extrasolar planets (exoplanets), especially those
located inside the habitable zone of their host stars, requires techniques
sensitive enough to detect the faint signals produced by those planets. The
radial velocity (RV) and photometric transit methods are the most widely used
and also the most efficient methods for detecting and characterizing
exoplanets. However, presence of astrophysical "noise" makes it difficult to
detect and accurately characterize exoplanets. It is important to note that the
amplitude of such astrophysical noise is larger than both the signal of
Earth-like exoplanets and state-of-the-art instrumentation limit precision,
making this a pressing topic that needs to be addressed. In this chapter, I
present a general review of the main sources of noise in photometric and RV
observations, namely, stellar oscillations, granulation, and magnetic activity.
Moreover, for each noise source I discuss the techniques and observational
strategies which allow us to mitigate their impact.Comment: 11 pages, 2 tables, Lecture presented at the IVth Azores
International Advanced School in Space Sciences on "Asteroseismology and
Exoplanets: Listening to the Stars and Searching for New Worlds"
(arXiv:1709.00645), which took place in Horta, Azores Islands, Portugal in
July 201
Solar-like oscillations in KIC11395018 and KIC11234888 from 8 months of Kepler data
We analyze the photometric short-cadence data obtained with the Kepler
Mission during the first eight months of observations of two solar-type stars
of spectral types G and F: KIC 11395018 and KIC 11234888 respectively, the
latter having a lower signal-to-noise ratio compared to the former. We estimate
global parameters of the acoustic (p) modes such as the average large and small
frequency separations, the frequency of the maximum of the p-mode envelope and
the average linewidth of the acoustic modes. We were able to identify and to
measure 22 p-mode frequencies for the first star and 16 for the second one even
though the signal-to-noise ratios of these stars are rather low. We also derive
some information about the stellar rotation periods from the analyses of the
low-frequency parts of the power spectral densities. A model-independent
estimation of the mean density, mass and radius are obtained using the scaling
laws. We emphasize the importance of continued observations for the stars with
low signal-to-noise ratio for an improved characterization of the oscillation
modes. Our results offer a preview of what will be possible for many stars with
the long data sets obtained during the remainder of the mission.Comment: 39 pages, 9 figures. Accepted for publication in Ap
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