3,809 research outputs found
Modeling effects of nonbreeders on population growth estimates
Acknowledgements We thank the Beissinger lab and reviewers for helpful comments on manuscript drafts. This research was funded by a Marie Curie International Outgoing Fellowship within the 7th European Community Framework Programme (project NON- BREEDERS). The contents of this paper reflect the views of the researchers, not the views of the European Commission. Data Accessibility R-code available from the Dryad Digital Repository: http://dx.doi.org/10.5061/dryad.t56cn (Lee, Reid & Beissinger, 2016).Peer reviewedPostprin
Vulnerability of horticultural crop production to extreme weather events
The potential impact of future extreme weather events on horticultural crops was evaluated. A review was carried out of the sensitivities of a representative set of crops
to environmental challenges. It confirmed that a range of environmental factors are capable of causing a significant impact on production, either as yield or quality loss.
The most important of these were un-seasonal temperature, water shortage or excess,and storms. Future scenarios were produced by the LARS-WG1, a stochastic weather generator linked with UKCIP02 projections of future climate. For the analyses, 150 years of synthetic weather data were generated for baseline, 2020HI and 2050HI scenarios at defined locations. The output from the weather generator was used in case studies, either to estimate the frequency of a defined set of circumstances known to have impact on cropping, or as inputs to models of crop scheduling or pest phenology or survival. The analyses indicated that episodes of summer drought severe enough to interrupt the continuity of supply of salads and other vegetables will increase while the frequency of autumns with sufficient rainfall to restrict potato lifting will decrease. They also indicated that the scheduling of winter cauliflowers for continuity of supply will require the deployment of varieties with different temperature sensitivities from those in use currently. In the pest insect studies, the number of batches of Agrotis segetum (cutworm) larvae surviving to third instar increased with time, as did the potential number of generations of Plutella xylostella (diamond-back moth) in the growing season, across a range of locations. The study demonstrated the utility of high resolution scenarios in predicting the likelihood of specific weather patterns and their potential effect on horticultural production. Several limitations of the current scenarios and biological models were also identified
Liver Allocation to Non-Citizen Non-Residents: An Ethical Framework for a Last-In-Line Approach
The incidence of non-U.S. citizen non-U.S. resident patients coming to the United States specifically for deceased donor liver transplantation raises compelling ethical questions that require careful consideration. The inclusion of these often financially and/or socially privileged patients in the pool of potential candidates for an absolutely scarce and life-saving liver transplant may exacerbate disparities already existing in deceased donor liver allocation. In addition, their inclusion on organ transplant waiting lists conflicts with recognized ethical principles of justice and reciprocity. Moreover, preliminary data suggest that public awareness of this practice could discourage organ donation, thereby worsening an already profound supply–demand gulf. Finally, U.S. organ allocation policies and statutes are out of step with recently promulgated international transplant guidelines, which prioritize self-sufficiency of organ programs. This article analyzes each of these ethical conflicts within the context of deceased donor liver transplantation and recommends policy changes that align the United States with international practices that discourage this scenario
The current state of biomarker research for Friedreich's ataxia: a report from the 2018 FARA biomarker meeting
The 2018 FARA Biomarker Meeting highlighted the current state of development of biomarkers for Friedreich's ataxia. A mass spectroscopy assay to sensitively measure mature frataxin (reduction of which is the root cause of disease) is being developed. Biomarkers to monitor neurological disease progression include imaging, electrophysiological measures and measures of nerve function, which may be measured either in serum and/or through imaging-based technologies. Potential pharmacodynamic biomarkers include metabolic and protein biomarkers and markers of nerve damage. Cardiac imaging and serum biomarkers may reflect cardiac disease progression. Considerable progress has been made in the development of biomarkers for various contexts of use, but further work is needed in terms of larger longitudinal multisite studies, and identification of novel biomarkers for additional use cases
The Population of Weak Mg II Absorbers I. A Survey of 26 QSO HIRES/Keck Spectra
We present a search for "weak" MgII absorbers [those with W_r(2796) < 0.3 A
in the HIRES/Keck spectra of 26 QSOs. We found 30, of which 23 are newly
discovered. The spectra are 80% complete to W_r(2796) = 0.02 A and have a
cumulative redshift path of ~17.2 for the redshift range 0.4 < z < 1.4. The
number of absorbers per unit redshift, dN/dz, is seen to increase as the
equivalent width threshold is decreased; we obtained dN/dz = 1.74+/-0.10 for
our 0.02 <= W_r(2796) < 0.3 A sample. The equivalent width distribution follows
a power law with slope -1.0; there is no turnover down to W_r(2796) = 0.02 A at
= 0.9. Weak absorbers comprise at least 65% of the total MgII absorption
population, which outnumbers Lyman limit systems (LLS) by a factor of
3.8+/-1.1; the majority of weak MgII absorbers must arise in sub-LLS
environments. Tentatively, we predict that ~5% of the Lyman-alpha forest clouds
with W_r(1215) > 0.1 A will have detectable MgII absorption to W_r,min(2796) =
0.02 A and that this is primarily a high-metallicity selection effect (Z/Z_sun]
> -1). This implies that MgII absorbing structures figure prominently as
tracers of sub-LLS environments where gas has been processed by stars. We
compare the number density of W_r(2796) > 0.02 A absorbers with that of both
high and low surface brightness galaxies and find a fiducial absorber size of
35h^-1 to 63h^-1 kpc, depending upon the assumed galaxy population and their
absorption properties. The individual absorbing "clouds" have W_r(2796) <= 0.15
A and their narrow (often unresolved) line widths imply temperatures of ~25,000
K. We measured W_r(1548) from CIV in FOS/HST archival spectra and, based upon
comparisons with FeII, found a range of ionization conditions (low, high, and
multi-phase) in absorbers selected by weak MgII.Comment: Accepted Version: 43 pages, PostScript figures embedded; accepted to
ApJ; updated version includes analysis of CIV absorptio
The Spatial, Ionization, and Kinematic Conditions of the z=1.39 Damped Ly-alpha Absorber in Q0957+561 A,B
We examined the sizes of the absorption clouds in a z=1.3911 damped Ly-alpha
absorber (DLA) in the double image lensed quasar Q0957+561 A,B (separation 135
pc at the absorber redshift). Using HIRES/Keck spectra, we studied the MgII
2796,2803 doublet, FeII multiplet, and MgI 2853 transition in absorption. We
defined six "clouds" in the system of sightline A and seven clouds in the
system of sightline B. An examination of the N(v) profiles, using the apparent
optical depth method, reveals no clear physical connection between the clouds
in A and those in B. The observed column density ratios of all clouds is
log[N(MgI)/N(FeII)] ~ -2 across the full velocity range in both systems and
also spatially (in both sightlines). This is a remarkable uniformity not seen
in Lyman limit systems. The uniformity of the cloud properties suggests that
the multiple clouds are not part of a "halo". Based upon photoionization
modeling, we constrain the ionization parameters in the range -6.2 < log(U) <
-5.1, where the range brackets known abundance ratio and dust depletion
patterns. The inferred cloud properties are densities of 2 < n_H < 20 cm^-3,
and line of sight sizes of 1 < D < 25 pc. The masses of the clouds in system A
are 10 < M/M_sun < 1000 and in system B are 1 < M/M_sun < 60 for spherical
clouds. For planar clouds, the upper limits are 400 M_sun and 160 M_sun for A
and B, respectively. We favor a model of the absorber in which the DLA region
itself is a single cloud in thiscomplex, which could be a parcel of gas in a
galactic ISM. A spherical cloud of ~10 pc would be limited to one of the
sightlines (A) and imply a covering factor less than 0.1 for the DLA complex.
We infer that the DLA cloud properties are consistent with those of lower
density, cold clouds in the Galactic interstellar medium.Comment: Accepted for publication in the Astrophysical Journal; final versio
In Vitro Maturation of a Humanized Shark VNAR Domain to Improve Its Biophysical Properties to Facilitate Clinical Development
Acknowledgments: The authors would like to acknowledge the funding support for this work from Scottish Enterprise [VNAR_001(2012)] and the Biotechnology and Biological Sciences Research Council (BB/K010905/1).Peer reviewedPublisher PD
The Environmental Context and Function of Burnt-Mounds : New Studies of Irish Fulachtaí Fiadh
The authors acknowledge funding from The Leverhulme Trust (F/00144/AI) and assistance from a large number of individuals including; Margaret Gowen (access to sites and assistance throughout),A. Ames, H, Essex (pollen processing), S. Rouillard & R. Smith (illustrations), C. McDermott, S. Bergerbrandt, all the staff of Margaret Gowen & Co. Ltd, TVAS Ireland and CRDS. Excavation works and some post-excavation analysis was paid for my Bord Gáis and the National Roads Authority (now Transport Infrastructure Ireland). Thanks also to David Smith for access to the Maureen Girling collection and assistance with identifications.Peer reviewedPostprintPostprin
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Individual and joint trajectories of change in bone, lean mass and physical performance in older men.
BackgroundDeclines in bone, muscle and physical performance are associated with adverse health outcomes in older adults. However, few studies have described concurrent age-related patterns of change in these factors. The purpose of this study was to characterize change in four properties of muscle, physical performance, and bone in a prospective cohort study of older men.MethodsUsing repeated longitudinal data from up to four visits across 6.9 years from up to 4681 men (mean age at baseline 72.7 yrs. ±5.3) participating in the Osteoporotic Fractures in Men (MrOS) Study, we used group-based trajectory models (PROC TRAJ in SAS) to identify age-related patterns of change in four properties of muscle, physical performance, and bone: total hip bone mineral (BMD) density (g/m2) and appendicular lean mass/ht2 (kg/m2), by DXA; grip strength (kg), by hand dynamometry; and walking speed (m/s), by usual walking pace over 6 m. We also described joint trajectories in all pair-wise combinations of these measures. Mean posterior probabilities of placement in each trajectory (or joint membership in latent groups) were used to assess internal reliability of the model. The number of trajectories for each individual factor was limited to three, to ensure that the pair-wise determination of joint trajectories would yield a tractable number of groups as well as model fit considerations.ResultsThe patterns of change identified were generally similar for all measures, with three district groups declining over time at roughly similar rates; joint trajectories revealed similar patterns with no cross-over or convergence between groups. Mean posterior probabilities for all trajectories were similar and consistently above 0.8 indicating reasonable model fit to the data.ConclusionsOur description of trajectories of change with age in bone mineral density, grip strength, walking speed and appendicular lean mass found that groups identified by these methods appeared to have little crossover or convergence of change with age, even when considering joint trajectories of change in these factors
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