63 research outputs found
Is cosmology consistent?
We perform a detailed analysis of the latest CMB measurements (including
BOOMERaNG, DASI, Maxima and CBI), both alone and jointly with other
cosmological data sets involving, e.g., galaxy clustering and the Lyman Alpha
Forest. We first address the question of whether the CMB data are internally
consistent once calibration and beam uncertainties are taken into account,
performing a series of statistical tests. With a few minor caveats, our answer
is yes, and we compress all data into a single set of 24 bandpowers with
associated covariance matrix and window functions. We then compute joint
constraints on the 11 parameters of the ``standard'' adiabatic inflationary
cosmological model. Out best fit model passes a series of physical consistency
checks and agrees with essentially all currently available cosmological data.
In addition to sharp constraints on the cosmic matter budget in good agreement
with those of the BOOMERaNG, DASI and Maxima teams, we obtain a heaviest
neutrino mass range 0.04-4.2 eV and the sharpest constraints to date on gravity
waves which (together with preference for a slight red-tilt) favors
``small-field'' inflation models.Comment: Replaced to match accepted PRD version. 14 pages, 12 figs. Tiny
changes due to smaller DASI & Maxima calibration errors. Expanded neutrino
and tensor discussion, added refs, typos fixed. Combined CMB data, window and
covariance matrix at http://www.hep.upenn.edu/~max/consistent.html or from
[email protected]
Weak Lensing and CMB: Parameter forecasts including a running spectral index
We use statistical inference theory to explore the constraints from future
galaxy weak lensing (cosmic shear) surveys combined with the current CMB
constraints on cosmological parameters, focusing particularly on the running of
the spectral index of the primordial scalar power spectrum, . Recent
papers have drawn attention to the possibility of measuring by
combining the CMB with galaxy clustering and/or the Lyman- forest. Weak
lensing combined with the CMB provides an alternative probe of the primordial
power spectrum. We run a series of simulations with variable runnings and
compare them to semi-analytic non-linear mappings to test their validity for
our calculations. We find that a ``Reference'' cosmic shear survey with
and galaxies per steradian can reduce the
uncertainty on and by roughly a factor of 2 relative to the
CMB alone. We investigate the effect of shear calibration biases on lensing by
including the calibration factor as a parameter, and show that for our
Reference Survey, the precision of cosmological parameter determination is only
slightly degraded even if the amplitude calibration is uncertain by as much as
5%. We conclude that in the near future weak lensing surveys can supplement the
CMB observations to constrain the primordial power spectrum.Comment: 12 pages, 10 figures, revtex4. Final form to appear in Phys Rev
The last stand before MAP: cosmological parameters from lensing, CMB and galaxy clustering
Cosmic shear measurements have now improved to the point where they deserve
to be treated on par with CMB and galaxy clustering data for cosmological
parameter analysis, using the full measured aperture mass variance curve rather
than a mere phenomenological parametrization thereof. We perform a detailed
9-parameter analysis of recent lensing (RCS), CMB (up to Archeops) and galaxy
clustering (2dF) data, both separately and jointly. CMB and 2dF data are
consistent with a simple flat adiabatic scale-invariant model with
Omega_Lambda=0.72+/-0.09, omega_cdm=0.115+/- 0.013, omega_b=0.024+/-0.003, and
a hint of reionization around z~8. Lensing helps further tighten these
constraints, but reveals tension regarding the power spectrum normalization:
including the RCS survey results raises sigma8 significantly and forces other
parameters to uncomfortable values. Indeed, sigma8 is emerging as the currently
most controversial cosmological parameter, and we discuss possible resolutions
of this sigma8 problem. We also comment on the disturbing fact that many recent
analyses (including this one) obtain error bars smaller than the Fisher matrix
bound. We produce a CMB power spectrum combining all existing experiments, and
using it for a "MAP versus world" comparison next month will provide a powerful
test of how realistic the error estimates have been in the cosmology community.Comment: Added references and Fisher error discussion. Combined CMB data,
window and covariance matrix for January "MAP vs World" contest at
http://www.hep.upenn.edu/~max/cmblsslens.html or from [email protected]
Seasonal drought limits tree species across the Neotropics
Within the tropics, the species richness of tree communities is strongly and positively associated with precipitation. Previous research has suggested that this macroecological pattern is driven by the negative effect of water-stress on the physiological processes of most tree species. This process implies that the range limits of taxa are defined by their ability to occur under dry conditions, and thus in terms of species distributions it predicts a nested pattern of taxa distribution from wet to dry areas. However, this ‘dry-tolerance’ hypothesis has yet to be adequately tested at large spatial and taxonomic scales. Here, using a dataset of 531 inventory plots of closed canopy forest distributed across the Western Neotropics we investigated how precipitation, evaluated both as mean annual precipitation and as the maximum climatological water deficit, influences the distribution of tropical tree species, genera and families. We find that the distributions of tree taxa are indeed nested along precipitation gradients in the western Neotropics. Taxa tolerant to seasonal drought are disproportionally widespread across the precipitation gradient, with most reaching even the wettest climates sampled; however, most taxa analysed are restricted to wet areas. Our results suggest that the ‘dry tolerance’ hypothesis has broad applicability in the world's most species-rich forests. In addition, the large number of species restricted to wetter conditions strongly indicates that an increased frequency of drought could severely threaten biodiversity in this region. Overall, this study establishes a baseline for exploring how tropical forest tree composition may change in response to current and future environmental changes in this region
Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020
We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe
The AURORA Study: a longitudinal, multimodal library of brain biology and function after traumatic stress exposure
Adverse posttraumatic neuropsychiatric sequelae (APNS) are common among civilian trauma survivors and military veterans. These APNS, as traditionally classified, include posttraumatic stress, postconcussion syndrome, depression, and regional or widespread pain. Traditional classifications have come to hamper scientific progress because they artificially fragment APNS into siloed, syndromic diagnoses unmoored to discrete components of brain functioning and studied in isolation. These limitations in classification and ontology slow the discovery of pathophysiologic mechanisms, biobehavioral markers, risk prediction tools, and preventive/treatment interventions. Progress in overcoming these limitations has been challenging because such progress would require studies that both evaluate a broad spectrum of posttraumatic sequelae (to overcome fragmentation) and also perform in-depth biobehavioral evaluation (to index sequelae to domains of brain function). This article summarizes the methods of the Advancing Understanding of RecOvery afteR traumA (AURORA) Study. AURORA conducts a large-scale (n = 5000 target sample) in-depth assessment of APNS development using a state-of-the-art battery of self-report, neurocognitive, physiologic, digital phenotyping, psychophysical, neuroimaging, and genomic assessments, beginning in the early aftermath of trauma and continuing for 1 year. The goals of AURORA are to achieve improved phenotypes, prediction tools, and understanding of molecular mechanisms to inform the future development and testing of preventive and treatment interventions
Riociguat treatment in patients with chronic thromboembolic pulmonary hypertension: Final safety data from the EXPERT registry
Objective: The soluble guanylate cyclase stimulator riociguat is approved for the treatment of adult patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) following Phase
Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses
To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely
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