242 research outputs found
Limited diversity in natal origins of immature anadromous fish during ocean residency
Author Posting. © The Authors, 2009. This is the author's version of the work. It is posted here by permission of NRC Research Press for personal use, not for redistribution. The definitive version was published in Canadian Journal of Fisheries and Aquatic Sciences. 67 (2010): 1699-1707, doi:10.1139/F10-086.Variable migration patterns can play a significant role in promoting diverse life history traits among populations. However, population and stage specific movement patterns are generally unknown yet crucial aspects of life history strategies in many highly migratory species. We used a natural tag approach using geochemical signatures in otoliths to identify natal origins of one-year-old anadromous American shad (Alosa sapidissima) during ocean residency. Otolith signatures of migrants were compared to a database of baseline signatures from 20 source populations throughout their spawning range. Samples were dominated by fish from only two rivers, while all other potential source populations were nearly or completely absent. These data support the hypothesis that American shad exhibit diverse migratory behaviors and immature individuals from populations throughout the native range do not all mix on northern summer feeding grounds. Rather, our results suggest populations of anadromous fish are distributed heterogeneously at sea in the first year of life and thus may encounter different ocean conditions at a critical early life history stage.This work was funded by National Science Foundation grants OCE-0215905 and OCE-0134998 to SRT and by a WHOI Ocean Life Institute grant to BDW
D*-->Dpi and D*-->Dgamma decays: Axial coupling and Magnetic moment of D* meson
The axial coupling and the magnetic moment of D*-meson or, more specifically,
the couplings g(D*Dpi) and g(D*Dgamma), encode the non-perturbative QCD effects
describing the decays D*-->Dpi and D*-->Dgamma. We compute these quantities by
means of lattice QCD with Nf=2 dynamical quarks, by employing the Wilson
("clover") action. On our finer lattice (a=0.065 fm) we obtain: g(D*Dpi)=20 +/-
2, and g(D0*D0gamma)=[2.0 +/- 0.6]/GeV. This is the first determination of
g(D0*D0gamma) on the lattice. We also provide a short phenomenological
discussion and the comparison of our result with experiment and with the
results quoted in the literature.Comment: 22 pages, 3 figure
Next-generation test of cosmic inflation
The increasing precision of cosmological datasets is opening up new
opportunities to test predictions from cosmic inflation. Here we study the
impact of high precision constraints on the primordial power spectrum and show
how a new generation of observations can provide impressive new tests of the
slow-roll inflation paradigm, as well as produce significant discriminating
power among different slow-roll models. In particular, we consider
next-generation measurements of the Cosmic Microwave Background (CMB)
temperature anisotropies and (especially) polarization, as well as new
Lyman- measurements that could become practical in the near future. We
emphasize relationships between the slope of the power spectrum and its first
derivative that are nearly universal among existing slow-roll inflationary
models, and show how these relationships can be tested on several scales with
new observations. Among other things, our results give additional motivation
for an all-out effort to measure CMB polarization.Comment: 10 pages, 8 figures, to appear in PRD; major changes are a reanalysis
in terms of better cosmological parameters and clarifications on the
contributions of polarization and Lyman-alpha dat
Edge turbulence in ISTTOK : a multi-code fluid validation
Fluid models used to study the edge plasma region need to be benchmarked against similar conditions given that models can strongly differ in complexity and therefore the results they produce. Via this validation study undertaken through the framework of EUROfusion Enabling Research, four state-of-the art models - GBS, Hermes/BOUT++, HESEL and TOKAM3X - are compared to experimental plasma turbulence measurements on the ISTTOK tokamak. Statistical comparisons of simulation and experiment data show that fluid models used here can replicate most of the experiment in terms of and fluctuations. Furthermore, it is shown that without including more complex information (like core turbulence information and domain geometry details and magnetic topological aspects) in fluid models, the results recovered can fall short from the experimental results. Via the simulations using these codes, it is demonstrated that fluid models continue to be a good cost-effective tool in recovering many global aspects of edge plasma behaviour
Bodily tides near spin-orbit resonances
Spin-orbit coupling can be described in two approaches. The method known as
"the MacDonald torque" is often combined with an assumption that the quality
factor Q is frequency-independent. This makes the method inconsistent, because
the MacDonald theory tacitly fixes the rheology by making Q scale as the
inverse tidal frequency.
Spin-orbit coupling can be treated also in an approach called "the Darwin
torque". While this theory is general enough to accommodate an arbitrary
frequency-dependence of Q, this advantage has not yet been exploited in the
literature, where Q is assumed constant or is set to scale as inverse tidal
frequency, the latter assertion making the Darwin torque equivalent to a
corrected version of the MacDonald torque.
However neither a constant nor an inverse-frequency Q reflect the properties
of realistic mantles and crusts, because the actual frequency-dependence is
more complex. Hence the necessity to enrich the theory of spin-orbit
interaction with the right frequency-dependence. We accomplish this programme
for the Darwin-torque-based model near resonances. We derive the
frequency-dependence of the tidal torque from the first principles, i.e., from
the expression for the mantle's compliance in the time domain. We also explain
that the tidal torque includes not only the secular part, but also an
oscillating part.
We demonstrate that the lmpq term of the Darwin-Kaula expansion for the tidal
torque smoothly goes through zero, when the secondary traverses the lmpq
resonance (e.g., the principal tidal torque smoothly goes through nil as the
secondary crosses the synchronous orbit).
We also offer a possible explanation for the unexpected frequency-dependence
of the tidal dissipation rate in the Moon, discovered by LLR
Characterizing epidemiology of prediabetes, diabetes, and hypertension in Qataris: A cross-sectional study
Objectives To characterize the epidemiologic profiles of prediabetes mellitus (preDM), diabetes mellitus (DM), and hypertension (HTN) in Qataris using the nationally representative 2012 Qatar STEPwise Survey. Methods A secondary data analysis of a cross-sectional survey that included 2,497 Qatari nationals aged 18–64 years. Descriptive and analytical statistical analyses were conducted. Results Prevalence of preDM, DM, and HTN in Qataris aged 18–64 years was 11.9% (95% confidence interval [CI] 9.6%-14.7%), 10.4% (95% CI 8.4%-12.9%), and 32.9% (95% CI 30.4%-35.6%), respectively. Age was the common factor associated with the three conditions. Adjusted analyses showed that unhealthy diet (adjusted odds ratio (aOR) = 1.84, 95% CI 1.01–3.36) was significantly associated with preDM; that physical inactivity (aOR = 1.66, 95% CI 1.12–2.46), central obesity (aOR = 2.08, 95% CI 1.02–4.26), and HTN (aOR = 2.18, 95% CI 1.40–3.38) were significantly associated with DM; and that DM (aOR = 2.07, 95% CI 1.34–3.22) was significantly associated with HTN. Population attributable fraction of preDM associated with unhealthy diet was 7.7%; of DM associated with physical inactivity, central obesity, and HTN, respectively, was 14.9%, 39.8%, and 17.5%; and of HTN associated with DM was 3.0%. Conclusions One in five Qataris is living with either preDM or DM, and one in three is living with HTN, conditions that were found to be primarily driven by lifestyle factors. Prevention, control, and management of these conditions should be a national priority to reduce their disease burden and associated disease sequelae.This publication was made possible by NPRP grant number 10-1208-160017 from the Qatar National Research Fund (a member of Qatar Foundation)
Epidemiology of facial fractures: Incidence, prevalence and years lived with disability estimates from the Global Burden of Disease 2017 study
Background: The Global Burden of Disease Study (GBD) has historically produced estimates of causes of injury such as falls but not the resulting types of injuries that occur. The objective of this study was to estimate the global incidence, prevalence and years lived with disability (YLDs) due to facial fractures and to estimate the leading injurious causes of facial fracture. Methods: We obtained results from GBD 2017. First, the study estimated the incidence from each injury cause (eg, falls), and then the proportion of each cause that would result in facial fracture being the most disabling injury. Incidence, prevalence and YLDs of facial fractures are then calculated across causes. Results: Globally, in 2017, there were 7 538 663 (95% uncertainty interval 6 116 489 to 9 4
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