67 research outputs found
From Death to Recovery Following Hypoxia Ischemia: If TGFβ Is a Central Regulator, Is Integrin β8 the Switch?
Polymorphisms in the hypoxia-inducible factor 1 alpha gene in Mexican patients with preeclampsia: A case-control study
<p>Abstract</p> <p>Background</p> <p>Although the etiology of preeclampsia is still unclear, recent work suggests that changes in circulating angiogenic factors play a key role in its pathogenesis. In the trophoblast of women with preeclampsia, hypoxia-inducible factor 1 alpha (HIF-1α) is over-expressed, and induces the expression of non-angiogenic factors and inhibitors of trophoblast differentiation. This observation prompted the study of HIF-1α and its relation to preeclampsia. It has been described that the C1772T (P582S) and G1790A (A588T) polymorphisms of the <it>HIF1A </it>gene have significantly greater transcriptional activity, correlated with an increased expression of their proteins, than the wild-type sequence. In this work, we studied whether either or both <it>HIF1A </it>variants contribute to preeclampsia susceptibility.</p> <p>Results</p> <p>Genomic DNA was isolated from 150 preeclamptic and 105 healthy pregnant women. Exon 12 of the <it>HIF1A </it>gene was amplified by PCR, and the genotypes of <it>HIF1A </it>were determined by DNA sequencing.</p> <p>In preeclamptic women and controls, the frequencies of the T allele for C1772T were 4.3 vs. 4.8%, and the frequencies of the A allele for G1790A were 0.0 vs. 0.5%, respectively. No significant differences were found between groups.</p> <p>Conclusion</p> <p>The frequency of the C1772T and G1790A polymorphisms of the <it>HIF1A </it>gene is very low, and neither polymorphism is associated with the development of preeclampsia in the Mexican population.</p
The deep-subsurface sulfate reducer Desulfotomaculum kuznetsovii employs two methanol-degrading pathways
Methanol is generally metabolized through a pathway initiated by a cobalamine-containing methanol methyltransferase by anaerobic methylotrophs (such as methanogens and acetogens), or through oxidation to formaldehyde using a methanol dehydrogenase by aerobes. Methanol is an important substrate in deep-subsurface environments, where thermophilic sulfate-reducing bacteria of the genus Desulfotomaculum have key roles. Here, we study the methanol metabolism of Desulfotomaculum kuznetsovii strain 17T, isolated from a 3000-m deep geothermal water reservoir. We use proteomics to analyze cells grown with methanol and sulfate in the presence and absence of cobalt and vitamin B12. The results indicate the presence of two methanol-degrading pathways in D. kuznetsovii, a cobalt-dependent methanol methyltransferase and a cobalt-independent methanol dehydrogenase, which is further confirmed by stable isotope fractionation. This is the first report of a microorganism utilizing two distinct methanol conversion pathways. We hypothesize that this gives D. kuznetsovii a competitive advantage in its natural environment.Research was funded by grants of the Division of Chemical Sciences (CW-TOP 700.55.343) and Earth and Life Sciences (ALW 819.02.014) of The Netherlands Organisation for Scientific Research (NWO), the European Research Council (ERC grant 323009), and the Gravitation grant (024.002.002) of the Netherlands Ministry of Education, Culture and Scienceinfo:eu-repo/semantics/publishedVersio
Beam-helicity asymmetry in photon and pion electroproduction in the Delta(1232) resonance region at Q^2= 0.35 (GeV/c)^2
The beam-helicity asymmetry has been measured simultaneously for the
reactions (e p \to e p \gamma) and (e p \to e p \pi^0) in the
resonance region at 0.35 (GeV/c). The experiment was performed at
MAMI with a longitudinally polarized beam and an out-of-plane detection of the
proton. The results are compared with calculations based on Dispersion
Relations for virtual Compton scattering and with the MAID model for pion
electroproduction. There is an overall good agreement between experiment and
theoretical calculations. The remaining discrepancies may be ascribed to an
imperfect parametrization of some multipoles, mainly
contributing to the non-resonant background. The beam-helicity asymmetry in
both channels ( and ) shows a good sensitivity to these
multipoles and should allow future improvement in their parametrization.Comment: 7 pages, 8 figures, version to appear in EPJ
Dark Energy Survey Year 3 results: Magnification modeling and impact on cosmological constraints from galaxy clustering and galaxy-galaxy lensing
We study the effect of magnification in the Dark Energy Survey Year 3
analysis of galaxy clustering and galaxy-galaxy lensing, using two different
lens samples: a sample of Luminous red galaxies, redMaGiC, and a sample with a
redshift-dependent magnitude limit, MagLim. We account for the effect of
magnification on both the flux and size selection of galaxies, accounting for
systematic effects using the Balrog image simulations. We estimate the impact
of magnification on the galaxy clustering and galaxy-galaxy lensing cosmology
analysis, finding it to be a significant systematic for the MagLim sample. We
show cosmological constraints from the galaxy clustering auto-correlation and
galaxy-galaxy lensing signal with different magnifications priors, finding
broad consistency in cosmological parameters in CDM and CDM.
However, when magnification bias amplitude is allowed to be free, we find the
two-point correlations functions prefer a different amplitude to the fiducial
input derived from the image simulations. We validate the magnification
analysis by comparing the cross-clustering between lens bins with the
prediction from the baseline analysis, which uses only the auto-correlation of
the lens bins, indicating systematics other than magnification may be the cause
of the discrepancy. We show adding the cross-clustering between lens redshift
bins to the fit significantly improves the constraints on lens magnification
parameters and allows uninformative priors to be used on magnification
coefficients, without any loss of constraining power or prior volume concerns.Comment: 21 pages, 13 figures, See this
https://www.darkenergysurvey.org/des-year-3-cosmology-results-papers/ URL for
the full DES Y3 cosmology releas
Weak lensing magnification in the dark energy survey science verification data
In this paper, the effect of weak lensing magnification on galaxy number counts is studied by cross-correlating the positions of two galaxy samples, separated by redshift, using the Dark Energy Survey Science Verification data set. This analysis is carried out for galaxies that are selected only by its photometric redshift. An extensive analysis of the systematic effects, using new methods based on simulations is performed, including a Monte Carlo sampling of the selection function of the survey
Joint analysis of DES Year 3 data and CMB lensing from SPT and Planck III: Combined cosmological constraints
We present cosmological constraints from the analysis of two-point
correlation functions between galaxy positions and galaxy lensing measured in
Dark Energy Survey (DES) Year 3 data and measurements of cosmic microwave
background (CMB) lensing from the South Pole Telescope (SPT) and Planck. When
jointly analyzing the DES-only two-point functions and the DES
cross-correlations with SPT+Planck CMB lensing, we find and , assuming CDM. When additionally combining with measurements of
the CMB lensing autospectrum, we find and . The high signal-to-noise
of the CMB lensing cross-correlations enables several powerful consistency
tests of these results, including comparisons with constraints derived from
cross-correlations only, and comparisons designed to test the robustness of the
galaxy lensing and clustering measurements from DES. Applying these tests to
our measurements, we find no evidence of significant biases in the baseline
cosmological constraints from the DES-only analyses or from the joint analyses
with CMB lensing cross-correlations. However, the CMB lensing
cross-correlations suggest possible problems with the correlation function
measurements using alternative lens galaxy samples, in particular the redMaGiC
galaxies and high-redshift MagLim galaxies, consistent with the findings of
previous studies. We use the CMB lensing cross-correlations to identify
directions for further investigating these problems.Comment: 20 pages, 15 figure
Joint analysis of DES Year 3 data and CMB lensing from SPT and Planck I: Construction of CMB Lensing Maps and Modeling Choices
Joint analyses of cross-correlations between measurements of galaxy
positions, galaxy lensing, and lensing of the cosmic microwave background (CMB)
offer powerful constraints on the large-scale structure of the Universe. In a
forthcoming analysis, we will present cosmological constraints from the
analysis of such cross-correlations measured using Year 3 data from the Dark
Energy Survey (DES), and CMB data from the South Pole Telescope (SPT) and
Planck. Here we present two key ingredients of this analysis: (1) an improved
CMB lensing map in the SPT-SZ survey footprint, and (2) the analysis
methodology that will be used to extract cosmological information from the
cross-correlation measurements. Relative to previous lensing maps made from the
same CMB observations, we have implemented techniques to remove contamination
from the thermal Sunyaev Zel'dovich effect, enabling the extraction of
cosmological information from smaller angular scales of the cross-correlation
measurements than in previous analyses with DES Year 1 data. We describe our
model for the cross-correlations between these maps and DES data, and validate
our modeling choices to demonstrate the robustness of our analysis. We then
forecast the expected cosmological constraints from the galaxy survey-CMB
lensing auto and cross-correlations. We find that the galaxy-CMB lensing and
galaxy shear-CMB lensing correlations will on their own provide a constraint on
at the few percent level, providing a
powerful consistency check for the DES-only constraints. We explore scenarios
where external priors on shear calibration are removed, finding that the joint
analysis of CMB lensing cross-correlations can provide constraints on the shear
calibration amplitude at the 5 to 10% level.Comment: 30 pages, 20 figures, To be submitted to PR
Mapping and simulating systematics due to spatially varying observing conditions in DES science verification data
Spatially varying depth and the characteristics of observing conditions, such as seeing, airmass, or sky background, are major sources of systematic uncertainties in modern galaxy survey analyses, particularly in deep multi-epoch surveys. We present a framework to extract and project these sources of systematics onto the sky, and apply it to the Dark Energy Survey (DES) to map the observing conditions of the Science Verification (SV) data. The resulting distributions and maps of sources of systematics are used in several analyses of DES–SV to perform detailed null tests with the data, and also to incorporate systematics in survey simulations. We illustrate the complementary nature of these two approaches by comparing the SV data with BCC-UFig, a synthetic sky catalog generated by forward-modeling of the DES–SV images. We analyze the BCC-UFig simulation to construct galaxy samples mimicking those used in SV galaxy clustering studies. We show that the spatially varying survey depth imprinted in the observed galaxy densities and the redshift distributions of the SV data are successfully reproduced by the simulation and are well-captured by the maps of observing conditions. The combined use of the maps, the SV data, and the BCC-UFig simulation allows us to quantify the impact of spatial systematics on N(z), the redshift distributions inferred using photometric redshifts. We conclude that spatial systematics in the SV data are mainly due to seeing fluctuations and are under control in current clustering and weak-lensing analyses. However, they will need to be carefully characterized in upcoming phases of DES in order to avoid biasing the inferred cosmological results. The framework presented here is relevant to all multi-epoch surveys and will be essential for exploiting future surveys such as the Large Synoptic Survey Telescope, which will require detailed null tests and realistic end-to-end image simulations to correctly interpret the deep, high-cadence observations of the sky
Joint analysis of DES Year 3 data and CMB lensing from SPT and Planck II: Cross-correlation measurements and cosmological constraints
Cross-correlations of galaxy positions and galaxy shears with maps of
gravitational lensing of the cosmic microwave background (CMB) are sensitive to
the distribution of large-scale structure in the Universe. Such
cross-correlations are also expected to be immune to some of the systematic
effects that complicate correlation measurements internal to galaxy surveys. We
present measurements and modeling of the cross-correlations between galaxy
positions and galaxy lensing measured in the first three years of data from the
Dark Energy Survey with CMB lensing maps derived from a combination of data
from the 2500 deg SPT-SZ survey conducted with the South Pole Telescope and
full-sky data from the Planck satellite. The CMB lensing maps used in this
analysis have been constructed in a way that minimizes biases from the thermal
Sunyaev Zel'dovich effect, making them well suited for cross-correlation
studies. The total signal-to-noise of the cross-correlation measurements is
23.9 (25.7) when using a choice of angular scales optimized for a linear
(nonlinear) galaxy bias model. We use the cross-correlation measurements to
obtain constraints on cosmological parameters. For our fiducial galaxy sample,
which consist of four bins of magnitude-selected galaxies, we find constraints
of and ( and ) when assuming
linear (nonlinear) galaxy bias in our modeling. Considering only the
cross-correlation of galaxy shear with CMB lensing, we find and . Our constraints
on are consistent with recent cosmic shear measurements, but lower than
the values preferred by primary CMB measurements from Planck.Comment: 25 pages, 19 figures, submitted to PR
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