1,017 research outputs found
First Image of the Sun with MeerKAT Solar Observations: Opening a New Frontier in Solar Physics
Solar radio emissions provide several unique diagnostics to estimate
different physical parameters of the solar corona, which are otherwise simply
inaccessible. However, imaging the highly dynamic solar coronal emissions
spanning a large range of angular scales at radio wavelengths is extremely
challenging. At GHz frequencies, the MeerKAT radio telescope is possibly
globally the best-suited instrument at the present time and can provide
high-fidelity spectroscopic snapshot solar images. Here, we present the first
images of the Sun made using the observations with the MeerKAT at L-band (856
-- 1711 MHz). This work demonstrates the high fidelity of the MeerKAT solar
images through a comparison with simulated radio images at the MeerKAT
frequencies. The observed images show extremely good mophological similarities
with the simulated images. A detailed comparison between the simulated radio
map and observed MeerKAT radio images demonstrates that there is significant
missing flux density in MeerKAT images at the higher frequencies of the
observing band, though it can potentially be estimated and corrected for. We
believe once solar observations with the MeerKAT are commissioned, they will
not only enable a host of novel studies but also open the door to a large
unexplored phase space with significant discovery potential.Comment: Preparing for submission, 14 pages, 9 figure
From downbuilding to contractional reactivation of salt-sediment systems: insights from analog modeling.
This work studies salt-detached fold-and-thrust belts involving minibasins by means of physical analogue modeling. The experimental set up consist of a series of minibasins and diapirs built by downbuilding into a regular polygonal framework. The minibasins-diapir framework were then submitted to contraction, and for some examples accompanied by different rates of syncontractional sedimentation. We aimed at evaluating the influence of an initial salt basin geometry (i.e. equal thickness vs. along-strike tapered) on the development of the salt-sediment system, and how this influences the geometries and kinematics of fold-and-thrust belts. We also tested how these are influenced by different syncontractional sedimentation rates. Results show that major differences on the early salt structures occur during downbuilding as a result of original salt budget (i.e. from pillows to diapirs), with a positive correlation between amount of original salt and salt structure development. Initial contractional deformation is localized on the weaker salt bodies, favoring salt extrusion. Shortening is then transferred forwards once vertical salt feeders are welded (i.e. secondary welds), while basal (primary) welds are sheared, rolled or delaminated. Changes on structural styles occur abruptly along-strike as controlled by degree of development of the precontractional salt structures. Relatively low syncontractional sedimentation rate delays forward propagation of deformation and promotes minibasins tilting. With larger sedimentation rates, a thicker cover inhibits minibasins deformation and secondary welding and, promotes a more coherent mechanical beam detached on the basal weld. Our modeling is compared to natural fold-and-thrust belts such as the Zagros and the European Alps
From saltâbearing rifted margins to foldâandâthrust belts. Insights from analog modeling and northern calcareous alps case study
Analog modeling is used to study the role played by the inherited salt-sediment architecture of a salt-bearing rifted margin, developed by minibasin downbuilding and margin-scale gliding, and then incorporated into a fold-and-thrust belt system influenced by surface processes. Inherited salt bodies localize contractional deformation at different scales and the salt-sediment architecture determines structural styles of fold-and-thrust belts. In our analog models, a large-transport thrust detached along allochthonous model salt (silicone polymer) accumulated in a former distal raft system. And the squeezing of salt walls, together with the tilting of minibasins, accounted for most of the shortening in a salt wall-minibasin province. Shortening and surface processes promote the extrusion and erosion of about 75% of the original model salt. The role played by salt tectonics during the contraction of salt-bearing rifted margins could be underestimated because of the low salt-sediment ratio found in fold-and-thrust belts. Our modeling results are compared with and assist in the interpretation of a section along the Northern Calcareous Alps
The radial variation of the solar wind turbulence spectra near the kinetic break scale from Parker Solar Probe measurements
In this study we examine the radial dependence of the inertial and dissipation range indices, as well as the spectral break separating the inertial and dissipation range in power density spectra of interplanetary magnetic field fluctuations using Parker Solar Probe data from the fifth solar encounter between âŒ0.1 and âŒ0.7 au. The derived break wavenumber compares reasonably well with previous estimates at larger radial distances and is consistent with gyro-resonant damping of AlfvĂ©nic fluctuations by thermal protons. We find that the inertial scale power-law index varies between approximately â1.65 and â1.45. This is consistent with either the Kolmogorov (â5/3) or IroshnikovâKraichnan (â3/2) values, and has a very weak radial dependence with a possible hint that the spectrum becomes steeper closer to the Sun. The dissipation range power-law index, however, has a clear dependence on radial distance (and turbulence age), decreasing from â3 near 0.7 au (4 days) to â4 [±0.3] at 0.1 au (0.75 days) closer to the Sun
Seis festivales sinfĂłnicos-vocales
De cada obra s'ha digitalitzat un programa sencer. De la resta s'han digitalitzat les parts que són diferents.Directors : Napoleone Annovazzi, Ekitai Ahn, Paul van Kempen, Otmar Nussio, Richard Strauss, Eduard Toldrà Empresa José F. Arque
PDGF-BB serum levels are decreased in adult onset Pompe patients
Adult onset Pompe disease is a genetic disorder characterized by slowly progressive skeletal and respiratory muscle weakness. Symptomatic patients are treated with enzymatic replacement therapy with human recombinant alfa glucosidase. Motor functional tests and spirometry are commonly used to follow patients up. However, a serological biomarker that correlates with the progression of the disease could improve follow-up. We studied serum concentrations of TGFÎČ, PDGF-BB, PDGF-AA and CTGF growth factors in 37 adult onset Pompe patients and 45 controls. Moreover, all patients performed several muscle function tests, conventional spirometry, and quantitative muscle MRI using 3-point Dixon. We observed a statistically significant change in the serum concentration of each growth factor in patients compared to controls. However, only PDGF-BB levels were able to differentiate between asymptomatic and symptomatic patients, suggesting its potential role in the follow-up of asymptomatic patients. Moreover, our results point to a dysregulation of muscle regeneration as an additional pathomechanism of Pompe disease
Characterisation of age and polarity at onset in bipolar disorder
Background
Studying phenotypic and genetic characteristics of age at onset (AAO) and polarity at onset (PAO) in bipolar disorder can provide new insights into disease pathology and facilitate the development of screening tools.
Aims
To examine the genetic architecture of AAO and PAO and their association with bipolar disorder disease characteristics.
Method
Genome-wide association studies (GWASs) and polygenic score (PGS) analyses of AAO (n = 12 977) and PAO (n = 6773) were conducted in patients with bipolar disorder from 34 cohorts and a replication sample (n = 2237). The association of onset with disease characteristics was investigated in two of these cohorts.
Results
Earlier AAO was associated with a higher probability of psychotic symptoms, suicidality, lower educational attainment, not living together and fewer episodes. Depressive onset correlated with suicidality and manic onset correlated with delusions and manic episodes. Systematic differences in AAO between cohorts and continents of origin were observed. This was also reflected in single-nucleotide variant-based heritability estimates, with higher heritabilities for stricter onset definitions. Increased PGS for autism spectrum disorder (ÎČ = â0.34 years, s.e. = 0.08), major depression (ÎČ = â0.34 years, s.e. = 0.08), schizophrenia (ÎČ = â0.39 years, s.e. = 0.08), and educational attainment (ÎČ = â0.31 years, s.e. = 0.08) were associated with an earlier AAO. The AAO GWAS identified one significant locus, but this finding did not replicate. Neither GWAS nor PGS analyses yielded significant associations with PAO.
Conclusions
AAO and PAO are associated with indicators of bipolar disorder severity. Individuals with an earlier onset show an increased polygenic liability for a broad spectrum of psychiatric traits. Systematic differences in AAO across cohorts, continents and phenotype definitions introduce significant heterogeneity, affecting analyses
Measurement of differential cross sections for top quark pair production using the lepton plus jets final state in proton-proton collisions at 13 TeV
National Science Foundation (U.S.
Particle-flow reconstruction and global event description with the CMS detector
The CMS apparatus was identified, a few years before the start of the LHC operation at CERN, to feature properties well suited to particle-flow (PF) reconstruction: a highly-segmented tracker, a fine-grained electromagnetic calorimeter, a hermetic hadron calorimeter, a strong magnetic field, and an excellent muon spectrometer. A fully-fledged PF reconstruction algorithm tuned to the CMS detector was therefore developed and has been consistently used in physics analyses for the first time at a hadron collider. For each collision, the comprehensive list of final-state particles identified and reconstructed by the algorithm provides a global event description that leads to unprecedented CMS performance for jet and hadronic tau decay reconstruction, missing transverse momentum determination, and electron and muon identification. This approach also allows particles from pileup interactions to be identified and enables efficient pileup mitigation methods. The data collected by CMS at a centre-of-mass energy of 8 TeV show excellent agreement with the simulation and confirm the superior PF performance at least up to an average of 20 pileup interactions
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