2,577 research outputs found
Great Canadian Lagerstätten 1. Early Eocene Lagerstätten of the Okanagan Highlands (British Columbia and Washington State)
The Early Eocene Okanagan High lands series of lacustrine shale and coal deposits, in far western North Ameri ca, constitutes a significant group of fossil sites with exceptional preserva tion of a diverse suite of organisms (Lagerstätten). With contemporaneous basins arrayed across about 1000 kilo metres of southern British Columbia and northern Washington, these sites offer a unique opportunity to examine the paleoecology of terrestrial commu nities spanning a temperate, low-sea sonality landscape in a montane setting during a time of generally warm tem peratures across the globe. The Okana gan Highlands sites provide an unpar alleled comparative framework within which to examine this major turning point in terrestrial community develop ment during the emergence of their broad modern character.La série de dépôts lacustres de schiste et de charbon du début de l’Éocène des hautes terres d’Okanagan, aux con fins de l’ouest de l’Amérique du Nord, constituent un groupe important de sites fossiles particulièrement bien con servés de suites d’organismes diverses (Lagerstätten). De nos jours, ces sites forment en une bande d’environ 1 000 kilomètres, depuis le sud de la Colom bie-Britannique jusqu’au nord de l’État de Washington. Dans le contexte de réchauffement climatique, c’est l’occa sion ou jamais d’étudier la paléoécolo gie de communautés terrestres dans des conditions climatiques modérées dans un paysage de montagne à faible saisonnalité. Les sites des hautes terres d’Okanagan représentent un cadre de comparaison sans pareil permettant d’étudier les effets de ce tournant majeur sur le développement des prin cipales caractéristiques modernes de la communauté terrestre
Early responses to H7N9 in southern mainland China
This article is made available through the Brunel Open Access Publishing Fund. © 2014 Goodwin and Sun; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the
Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public
Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this
article, unless otherwise stated.Background: H7N9 posed potentially serious health challenges for Chinese society. The previous SARS outbreak in this country was accompanied by contradictory information, while worries about wide-spread influenza led to discrimination worldwide. Early understanding of public threat perceptions is therefore important for effective public health communication and intervention. Methods: We interviewed 1011 respondents by phone two weeks after the first case. Questions examined risk awareness and media use, beliefs about the emergence of the threat and those most at risk, anxiety about infection and preventive and avoidant behaviours. Results: Results demonstrate moderate levels of anxiety but relatively high levels of trust towards government officials. Threat emergence was associated with hygiene levels, temperature change, floating pigs in the Huangpu River and migration to the city. Anxiety predicted both recommended and non-recommended behavioural changes. Conclusions: Comparatively high levels of trust in Chinese government advice about H7N9 contrast positively with previous pandemic communications in China. Anxiety helped drive both recommended and non-recommended behaviours, with potentially important economic and social implications. This included evidence of 'othering’ of those associated with the threat (e.g. migrants). Findings emphasise the need to manage public communications early during new influenza outbreaks.Fudan Tydall Centre and Fudan Media and Public Opinion Center
Fingering Instability of Dislocations and Related Defects
We identify a fundamental morphological instability of mobile dislocations in
crystals and related line defects. A positive gradient in the local driving
force along the direction of defect motion destabilizes long-wavelength
vibrational modes, producing a ``fingering'' pattern. The minimum unstable
wavelength scales as the inverse square root of the force gradient. We
demonstrate the instability's onset in simulations of a screw dislocation in Al
(via molecular dynamics) and of a vortex in a 3-d XY ``rotator'' model.Comment: 4 pages, 3 figure
Comparing Suzaku and XMM-Newton Observations of the Soft X-ray Background: Evidence for Solar Wind Charge Exchange Emission
We present an analysis of a pair of Suzaku spectra of the soft X-ray
background (SXRB), obtained from pointings on and off a nearby shadowing
filament in the southern Galactic hemisphere. Because of the different Galactic
column densities in the two pointing directions, the observed emission from the
Galactic halo has a different shape in the two spectra. We make use of this
difference when modeling the spectra to separate the absorbed halo emission
from the unabsorbed foreground emission from the Local Bubble (LB). The
temperatures and emission measures we obtain are significantly different from
those determined from an earlier analysis of XMM-Newton spectra from the same
pointing directions. We attribute this difference to the presence of previously
unrecognized solar wind charge exchange (SWCX) contamination in the XMM-Newton
spectra, possibly due to a localized enhancement in the solar wind moving
across the line of sight. Contemporaneous solar wind data from ACE show nothing
unusual during the course of the XMM-Newton observations. Our results therefore
suggest that simply examining contemporaneous solar wind data might be
inadequate for determining if a spectrum of the SXRB is contaminated by SWCX
emission. If our Suzaku spectra are not badly contaminated by SWCX emission,
our best-fitting LB model gives a temperature of log T = 5.98 +0.03/-0.04 and a
pressure of p/k = 13,100-16,100 cm^-3 K. These values are lower than those
obtained from other recent observations of the LB, suggesting the LB may not be
isothermal and may not be in pressure equilibrium. Our halo modeling,
meanwhile, suggests that neon may be enhanced relative to oxygen and iron,
possibly because oxygen and iron are partly in dust.Comment: 17 pages, 8 figures. Accepted for publication in the Astrophysical
Journa
Structural Parameters of Thin and Thick Disks in Edge-On Disk Galaxies
We analyze the global structure of 34 late-type, edge-on, undisturbed, disk
galaxies spanning a wide range of mass. We measure structural parameters for
the galaxies using two-dimensional least-squares fitting to our -band
photometry. The fits require both a thick and a thin disk to adequately fit the
data. The thick disks have larger scale heights and longer scale lengths than
the embedded thin disks, by factors of ~2 and ~1.25, respectively. The observed
structural parameters agree well with the properties of thick and thin disks
derived from star counts in the Milky Way and from resolved stellar populations
in nearby galaxies. We find that massive galaxies' luminosities are dominated
by the thin disk. However, in low mass galaxies (Vc < 120 km/s), thick disk
stars contribute nearly half of the luminosity and dominate the stellar mass.
Thus, although low mass dwarf galaxies appear blue, the majority of their stars
are probably quite old.
Our data are most easily explained by a formation scenario where the thick
disk is assembled through direct accretion of stellar material from merging
satellites while the thin disk is formed from accreted gas. The baryonic
fraction in the thin disk therefore constrains the gas-richness of the merging
pre-galactic fragments. If we include the mass in HI as part of the thin disk,
the thick disk contains <10% of the baryons in high mass galaxies, and ~25-30%
of the baryons in low-mass galaxies. We discuss how our trends can be explained
by supernova-driven outflow at early times as well as the possibilities for
predicting abundance trends in thick disks, and for removing discrepancies
between semi-analytic galaxy formation models and the observed colors of low
mass galaxies. (abstract abridged)Comment: 25 pages, 24 figures, accepted for publication in A
Mechanisms of Cognitive Impairment in Cerebral Small Vessel Disease: Multimodal MRI Results from the St George's Cognition and Neuroimaging in Stroke (SCANS) Study.
Cerebral small vessel disease (SVD) is a common cause of vascular cognitive impairment. A number of disease features can be assessed on MRI including lacunar infarcts, T2 lesion volume, brain atrophy, and cerebral microbleeds. In addition, diffusion tensor imaging (DTI) is sensitive to disruption of white matter ultrastructure, and recently it has been suggested that additional information on the pattern of damage may be obtained from axial diffusivity, a proposed marker of axonal damage, and radial diffusivity, an indicator of demyelination. We determined the contribution of these whole brain MRI markers to cognitive impairment in SVD. Consecutive patients with lacunar stroke and confluent leukoaraiosis were recruited into the ongoing SCANS study of cognitive impairment in SVD (n = 115), and underwent neuropsychological assessment and multimodal MRI. SVD subjects displayed poor performance on tests of executive function and processing speed. In the SVD group brain volume was lower, white matter hyperintensity volume higher and all diffusion characteristics differed significantly from control subjects (n = 50). On multi-predictor analysis independent predictors of executive function in SVD were lacunar infarct count and diffusivity of normal appearing white matter on DTI. Independent predictors of processing speed were lacunar infarct count and brain atrophy. Radial diffusivity was a stronger DTI predictor than axial diffusivity, suggesting ischaemic demyelination, seen neuropathologically in SVD, may be an important predictor of cognitive impairment in SVD. Our study provides information on the mechanism of cognitive impairment in SVD
Patient-Centered Outcomes Measurement: Does It Require Information From Patients?
Purpose: Since collecting outcome measure data from patients can be expensive, time-consuming, and subject to memory and nonresponse bias, we sought to learn whether outcomes important to patients can be obtained from data in the electronic health record (EHR) or health insurance claims. Methods: We previously identified 21 outcomes rated important by patients who had advanced imaging tests for back or abdominal pain. Telephone surveys about experiencing those outcomes 1 year after their test from 321 people consenting to use of their medical record and claims data were compared with audits of the participants’ EHR progress notes over the time period between the imaging test and survey completion. We also compared survey data with algorithmically extracted data from claims files for outcomes for which data might be available from that source. Results: Of the 16 outcomes for which patients’ survey responses were considered to be the best information source, only 2 outcomes for back pain and 3 for abdominal pain had kappa scores above a very modest level of ≥ 0.2 for chart audit of EHR data and none for algorithmically obtained EHR/claims data. Of the other 5 outcomes for which claims data were considered to be the best information source, only 2 outcomes from patient surveys and 3 outcomes from chart audits had kappa scores ≥ 0.2. Conclusions: For the types of outcomes studied here, medical record or claims data do not provide an adequate source of information except for a few outcomes where patient reports may be less accurate
Methods and apparatus for constructing and implementing a universal extension module for processing objects in a database
Methods and apparatus for providing a multi-tier object-relational database architecture are disclosed. In one illustrative embodiment of the present invention, a multi-tier database architecture comprises an object-relational database engine as a top tier, one or more domain-specific extension modules as a bottom tier, and one or more universal extension modules as a middle tier. The individual extension modules of the bottom tier operationally connect with the one or more universal extension modules which, themselves, operationally connect with the database engine. The domain-specific extension modules preferably provide such functions as search, index, and retrieval services of images, video, audio, time series, web pages, text, XML, spatial data, etc. The domain-specific extension modules may include one or more IBM DB2 extenders, Oracle data cartridges and/or Informix datablades, although other domain-specific extension modules may be used
UWISH2 -- The UKIRT Widefield Infrared Survey for H2
We present the goals and preliminary results of an unbiased, near-infrared,
narrow-band imaging survey of the First Galactic Quadrant (10deg<l<65deg ;
-1.3deg<b<+1.3deg). This area includes most of the Giant Molecular Clouds and
massive star forming regions in the northern hemisphere. The survey is centred
on the 1-0S(1) ro-vibrational line of H2, a proven tracer of hot, dense
molecular gas in star-forming regions, around evolved stars, and in supernova
remnants. The observations complement existing and upcoming photometric surveys
(Spitzer-GLIMPSE, UKIDSS-GPS, JCMT-JPS, AKARI, Herschel Hi-GAL, etc.), though
we probe a dynamically active component of star formation not covered by these
broad-band surveys. Our narrow-band survey is currently more than 60% complete.
The median seeing in our images is 0.73arcsec. The images have a 5sigma
detection limit of point sources of K=18mag and the surface brightness limit is
10^-19Wm^-2arcsec^-2 when averaged over our typical seeing. Jets and outflows
from both low and high mass Young Stellar Objects are revealed, as are new
Planetary Nebulae and - via a comparison with earlier K-band observations
acquired as part of the UKIDSS GPS - numerous variable stars. With their
superior spatial resolution, the UWISH2 data also have the potential to reveal
the true nature of many of the Extended Green Objects found in the GLIMPSE
survey.Comment: 14pages, 8figures, 2tables, accepted for publication by MNRAS, a
version with higher resolution figures can be found at
http://astro.kent.ac.uk/~df
Bax Crystal Structures Reveal How BH3 Domains Activate Bax and Nucleate Its Oligomerization to Induce Apoptosis
SummaryIn stressed cells, apoptosis ensues when Bcl-2 family members Bax or Bak oligomerize and permeabilize the mitochondrial outer membrane. Certain BH3-only relatives can directly activate them to mediate this pivotal, poorly understood step. To clarify the conformational changes that induce Bax oligomerization, we determined crystal structures of BaxΔC21 treated with detergents and BH3 peptides. The peptides bound the Bax canonical surface groove but, unlike their complexes with prosurvival relatives, dissociated Bax into two domains. The structures define the sequence signature of activator BH3 domains and reveal how they can activate Bax via its groove by favoring release of its BH3 domain. Furthermore, Bax helices α2–α5 alone adopted a symmetric homodimer structure, supporting the proposal that two Bax molecules insert their BH3 domain into each other’s surface groove to nucleate oligomerization. A planar lipophilic surface on this homodimer may engage the membrane. Our results thus define critical Bax transitions toward apoptosis
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