155 research outputs found
Low energy conversion electron detection in superfluid He3 at ultra-low temperature
We report on the first results of the MACHe3 (MAtrix of Cells of Helium 3)
prototype experiment concerning the measurement of low energy conversion
electrons at ultra-low temperature. For the first time, the feasibility of the
detection of low energy electrons is demonstrated in superfluid He3-B cooled
down to 100 microK. Low energy electrons at 7.3 keV coming from the K shell
conversion of the 14.4 keV nuclear transition of a low activity Co57 source are
detected, opening the possibility to use a He3-based detector for the detection
of Weakly Interacting Massive Particles (WIMPs) which are expected to release
an amount of energy higher-bounded by 5.6 keV.Comment: 8 pages, 3 figures, to appear in NIM
Directional detection as a strategy to discover Galactic Dark Matter
Directional detection of Galactic Dark Matter is a promising search strategy
for discriminating genuine WIMP events from background ones. Technical progress
on gaseous detectors and read-outs has permitted the design and construction of
competitive experiments. However, to take full advantage of this powerful
detection method, one need to be able to extract information from an observed
recoil map to identify a WIMP signal. We present a comprehensive formalism,
using a map-based likelihood method allowing to recover the main incoming
direction of the signal and its significance, thus proving its galactic origin.
This is a blind analysis intended to be used on any directional data.
Constraints are deduced in the () plane and systematic
studies are presented in order to show that, using this analysis tool,
unambiguous dark matter detection can be achieved on a large range of exposures
and background levels.Comment: 20 pages, 5 figures Final version to appear in Phys. Lett.
La estructura sĂsmica de la corteza de la Zona de Ossa Morena y su interpretaciĂłn geolĂłgica
El experimento de sĂsmica de reflexiĂłn profunda IBERSEIS ha proporcionado una imagen de la corteza del OrĂłgeno Varisco en el sudoeste de Iberia. Este artĂculo se centra en la descripciĂłn de la corteza de la Zona de Ossa Morena (OMZ), que estĂĄ claramente dividida en una corteza superior, con reflectividad de buzamiento al NE, y una corteza inferior de pobre reflectividad. Las estructuras geolĂłgicas cartografiadas en superficie se correlacionan bien con la reflectividad de la corteza superior, y en la imagen sĂsmica se ven enraizar en la corteza media. Ăsta estĂĄ constituida por un cuerpo muy reflectivo, interpretado como una gran intrusiĂłn de rocas bĂĄsicas. La imagen de las suturas que limitan la OMZ muestra el carĂĄcter fuertemente transpresivo de la colisiĂłn orogĂ©nica varisca registrada en el sudoeste de Iberia. La Moho actual es plana y, en consecuencia, no se observa la raĂz del orĂłgeno
Dendritic cell deficiencies persist seven months after SARS-CoV-2 infection
Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV)-2 infection induces an exacerbated inflammation driven by innate immunity components. Dendritic cells (DCs) play a key role in the defense against viral infections, for instance plasmacytoid DCs (pDCs), have the capacity to produce vast amounts of interferon-alpha (IFN-α). In COVID-19 there is a deficit in DC numbers and IFN-α production, which has been associated with disease severity. In this work, we described that in addition to the DC deficiency, several DC activation and homing markers were altered in acute COVID-19 patients, which were associated with multiple inflammatory markers. Remarkably, previously hospitalized and nonhospitalized patients remained with decreased numbers of CD1c+ myeloid DCs and pDCs seven months after SARS-CoV-2 infection. Moreover, the expression of DC markers such as CD86 and CD4 were only restored in previously nonhospitalized patients, while no restoration of integrin ÎČ7 and indoleamine 2,3-dyoxigenase (IDO) levels were observed. These findings contribute to a better understanding of the immunological sequelae of COVID-19
Planck intermediate results. XLVIII. Disentangling Galactic dust emission and cosmic infrared background anisotropies
Using the Planck 2015 data release (PR2) temperature maps, we separate Galactic thermal dust emission from cosmic infrared background (CIB) anisotropies. For this purpose, we implement a specifically tailored component-separation method, the so-called generalized needlet internal linear combination (GNILC) method, which uses spatial information (the angular powerspectra) to disentangle the Galactic dust emission and CIB anisotropies. We produce significantly improved all-sky maps of Planck thermal dust emission, with reduced CIB contamination, at 353, 545, and 857 GHz. By reducing the CIB contamination of the thermal dust maps, we provide more accurate estimates of the local dust temperature and dust spectral index over the sky with reduced dispersion, especially at high Galactic latitudes above b = ±20°. We find that the dust temperature is T = (19.4 ± 1.3) K and the dust spectral index is ÎČ = 1.6 ± 0.1 averaged over the whole sky, while T = (19.4 ± 1.5) K and ÎČ = 1.6 ± 0.2 on 21% of the sky at high latitudes. Moreover, subtracting the new CIB-removed thermal dust maps from the CMB-removed Planck maps gives access to the CIB anisotropies over 60% of the sky at Galactic latitudes |b| > 20°. Because they are a significant improvement over previous Planck products, the GNILC maps are recommended for thermal dust science. The new CIB maps can be regarded as indirect tracers of the dark matter and they are recommended for exploring cross-correlations with lensing and large-scale structure optical surveys. The reconstructed GNILC thermal dust and CIB maps are delivered as Planck products
SARS-CoV-2 viral load in nasopharyngeal swabs is not an independent predictor of unfavorable outcome
The aim was to assess the ability of nasopharyngeal SARS-CoV-2 viral load at first patientâs hospital evaluation to predict unfavorable outcomes. We conducted a prospective cohort study including 321 adult patients with confirmed COVID-19 through RT-PCR in nasopharyngeal swabs. Quantitative Synthetic SARS-CoV-2 RNA cycle threshold values were used to calculate the viral load in log10 copies/mL. Disease severity at the end of follow up was categorized into mild, moderate, and severe. Primary endpoint was a composite of intensive care unit (ICU) admission and/or death (nâ=â85, 26.4%). Univariable and multivariable logistic regression analyses were performed. Nasopharyngeal SARS-CoV-2 viral load over the second quartile (â„â7.35 log10 copies/mL, pâ=â0.003) and second tertile (â„â8.27 log10 copies/mL, pâ=â0.01) were associated to unfavorable outcome in the unadjusted logistic regression analysis. However, in the final multivariable analysis, viral load was not independently associated with an unfavorable outcome. Five predictors were independently associated with increased odds of ICU admission and/or death: ageââ„â70 years, SpO2, neutrophilsâ>â7.5âĂâ103/”L, lactate dehydrogenaseââ„â300 U/L, and C-reactive proteinââ„â100 mg/L. In summary, nasopharyngeal SARS-CoV-2 viral load on admission is generally high in patients with COVID-19, regardless of illness severity, but it cannot be used as an independent predictor of unfavorable clinical outcome
Planck 2018 results. IV. Diffuse component separation
We present full-sky maps of the cosmic microwave background (CMB) and polarized synchrotron and thermal dust emission, derived from the third set of Planck frequency maps. These products have significantly lower contamination from instrumental systematic effects than previous versions. The methodologies used to derive these maps follow closely those described in earlier papers, adopting four methods (Commander, NILC, SEVEM, and SMICA) to extract the CMB component, as well as three methods (Commander, GNILC, and SMICA) to extract astrophysical components. Our revised CMB temperature maps agree with corresponding products in the Planck 2015 delivery, whereas the polarization maps exhibit significantly lower large-scale power, reflecting the improved data processing described in companion papers; however, the noise properties of the resulting data products are complicated, and the best available end-to-end simulations exhibit relative biases with respect to the data at the few percent level. Using these maps, we are for the first time able to fit the spectral index of thermal dust independently over 3 degree regions. We derive a conservative estimate of the mean spectral index of polarized thermal dust emission of beta_d = 1.55 +/- 0.05, where the uncertainty marginalizes both over all known systematic uncertainties and different estimation techniques. For polarized synchrotron emission, we find a mean spectral index of beta_s = -3.1 +/- 0.1, consistent with previously reported measurements. We note that the current data processing does not allow for construction of unbiased single-bolometer maps, and this limits our ability to extract CO emission and correlated components. The foreground results for intensity derived in this paper therefore do not supersede corresponding Planck 2015 products. For polarization the new results supersede the corresponding 2015 products in all respects
Deep-sequencing reveals broad subtype-specific HCV resistance mutations associated with treatment failure
A percentage of hepatitis C virus (HCV)-infected patients fail direct acting antiviral (DAA)-based treatment regimens, often because of drug resistance-associated substitutions (RAS). The aim of this study was to characterize the resistance profile of a large cohort of patients failing DAA-based treatments, and investigate the relationship between HCV subtype and failure, as an aid to optimizing management of these patients. A new, standardized HCV-RAS testing protocol based on deep sequencing was designed and applied to 220 previously subtyped samples from patients failing DAA treatment, collected in 39 Spanish hospitals. The majority had received DAA-based interferon (IFN) a-free regimens; 79% had failed sofosbuvir-containing therapy. Genomic regions encoding the nonstructural protein (NS) 3, NS5A, and NS5B (DAA target regions) were analyzed using subtype-specific primers. Viral subtype distribution was as follows: genotype (G) 1, 62.7%; G3a, 21.4%; G4d, 12.3%; G2, 1.8%; and mixed infections 1.8%. Overall, 88.6% of patients carried at least 1 RAS, and 19% carried RAS at frequencies below 20% in the mutant spectrum. There were no differences in RAS selection between treatments with and without ribavirin. Regardless of the treatment received, each HCV subtype showed specific types of RAS. Of note, no RAS were detected in the target proteins of 18.6% of patients failing treatment, and 30.4% of patients had RAS in proteins that were not targets of the inhibitors they received. HCV patients failing DAA therapy showed a high diversity of RAS. Ribavirin use did not influence the type or number of RAS at failure. The subtype-specific pattern of RAS emergence underscores the importance of accurate HCV subtyping. The frequency of âextra-targetâ RAS suggests the need for RAS screening in all three DAA target regions
Planck 2018 results. III. High Frequency Instrument data processing and frequency maps
This paper presents the High Frequency Instrument (HFI) data processing procedures for the Planck 2018 release. Major improvements in mapmaking have been achieved since the previous 2015 release. They enabled the first significant measurement of the reionization optical depth parameter using HFI data. This paper presents an extensive analysis of systematic effects, including the use of simulations to facilitate their removal and characterize the residuals. The polarized data, which presented a number of known problems in the 2015 Planck release, are very significantly improved. Calibration, based on the CMB dipole, is now extremely accurate and in the frequency range 100 to 353 GHz reduces intensity-to-polarization leakage caused by calibration mismatch. The Solar dipole direction has been determined in the three lowest HFI frequency channels to within one arc minute, and its amplitude has an absolute uncertainty smaller than K, an accuracy of order . This is a major legacy from the HFI for future CMB experiments. The removal of bandpass leakage has been improved by extracting the bandpass-mismatch coefficients for each detector as part of the mapmaking process; these values in turn improve the intensity maps. This is a major change in the philosophy of "frequency maps", which are now computed from single detector data, all adjusted to the same average bandpass response for the main foregrounds. Simulations reproduce very well the relative gain calibration of detectors, as well as drifts within a frequency induced by the residuals of the main systematic effect. Using these simulations, we measure and correct the small frequency calibration bias induced by this systematic effect at the level. There is no detectable sign of a residual calibration bias between the first and second acoustic peaks in the CMB channels, at the level
Planck 2018 results. XII. Galactic astrophysics using polarized dust emission
We present 353 GHz full-sky maps of the polarization fraction , angle , and dispersion of angles of Galactic dust thermal emission produced from the 2018 release of Planck data. We confirm that the mean and maximum of decrease with increasing . The uncertainty on the maximum polarization fraction, % at 80 arcmin resolution, is dominated by the uncertainty on the zero level in total intensity. The observed inverse behaviour between and is interpreted with models of the polarized sky that include effects from only the topology of the turbulent Galactic magnetic field. Thus, the statistical properties of , , and mostly reflect the structure of the magnetic field. Nevertheless, we search for potential signatures of varying grain alignment and dust properties. First, we analyse the product map , looking for residual trends. While decreases by a factor of 3--4 between cm and cm, decreases by only about 25%, a systematic trend observed in both the diffuse ISM and molecular clouds. Second, we find no systematic trend of with the dust temperature, even though in the diffuse ISM lines of sight with high and low tend to have colder dust. We also compare Planck data with starlight polarization in the visible at high latitudes. The agreement in polarization angles is remarkable. Two polarization emission-to-extinction ratios that characterize dust optical properties depend only weakly on and converge towards the values previously determined for translucent lines of sight. We determine an upper limit for the polarization fraction in extinction of 13%, compatible with the observed in emission. These results provide strong constraints for models of Galactic dust in diffuse gas
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