2,171 research outputs found
Observations of the first electromagnetic counterpart to a gravitational wave source by the TOROS collaboration
We present the results of prompt optical follow-up of the electromagnetic counterpart of GW170817 by the Transient Optical Robotic Observatory of the South Collaboration (TOROS). We detected highly significant dimming in the light curves of the counterpart over the course of only 80 minutes of observations obtained ∼35 hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ∼59 hr after the event with the EABA 1.5m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a blue kilonova relatively free of lanthanides
Lessons from the operation of the "Penning-Fluorescent" TPC and prospects
We have recently reported the development of a new type of high-pressure
Xenon time projection chamber operated with an ultra-low diffusion mixture and
that simultaneously displays Penning effect and fluorescence in the
near-visible region (300 nm). The concept, dubbed `Penning-Fluorescent' TPC,
allows the simultaneous reconstruction of primary charge and scintillation with
high topological and calorimetric fidelity
Dy3+- and Pr3+-doped phosphate glass optical fibres for laser emission at visible wavelengths
Visible lasers find applications in many fields such as medicine, materials processing, display and entertainment technology, microscopy and scientific research
Data preprocessing workflow for exhaled breath analysis by GC/MS using open sources
© 2020 The Authors. This document is made available under the CC-BY 4.0 license. http://creativecommons.org/licenses/by /4.0/
This document is the Accepted version of a Published Work that appeared in final form in Scientifc Reports. To access the final edited and published work see https://doi.org/10.1038/s41598-020-79014-
Constraints on the Minimal Supergravity Model with Large
In the minimal supergravity model (mSUGRA), as the parameter
increases, the charged Higgs boson and light bottom squark masses decrease,
which can potentially increase contributions from , \tg\tb_j and
\tz_i\tb_j loops in the decay . We update a previous QCD
improved decay calculation to include in addition the effects of
gluino and neutralino loops. We find that in the mSUGRA model, loops involving
charginos also increase, and dominate over , , \tg\tq and
\tz_i\tq contributions for \tan\beta\agt 5-10. We find for large values of
that most of the parameter space of the mSUGRA model for
is ruled out due to too large a value of branching ratio . For and large , most of parameter space is
allowed, although the regions with the least fine-tuning (low and
) are ruled out due to too low a value of . We
compare the constraints from to constraints from the neutralino
relic density, and to expectations for sparticle discovery at LEP2 and the
Fermilab Tevatron colliders. Finally, we show that non-universal GUT
scale soft breaking squark mass terms can enhance gluino loop contributions to
decay rate even if these are diagonal.Comment: 14 page REVTEX file plus 6 PS figure
Reconstructing the universe history, from inflation to acceleration, with phantom and canonical scalar fields
We consider the reconstruction technique in theories with a single or
multiple (phantom and/or canonical) scalar fields. With the help of several
examples, it is demonstrated explicitly that the universe expansion history,
unifying early-time inflation and late-time acceleration, can be realized in
scalar-tensor gravity. This is generalized to the theory of a scalar field
coupled non-minimally to the curvature and to a Brans-Dicke-like theory.
Different examples of unification of inflation with cosmic acceleration, in
which de Sitter, phantom, and quintessence type fields play the fundamental
role--in different combinations--are worked out. Specifically, the frame
dependence and stability properties of de Sitter space scalar field theory are
studied. Finally, for two-scalar theories, the late-time acceleration and
early-time inflation epochs are successfully reconstructed, in realistic
situations in which the more and more stringent observational bounds are
satisfied, using the freedom of choice of the scalar field potential, and of
the kinetic factor.Comment: 22 pages, revtex, no figures, version to appear in Phys. Rev.
Primary productivity determinants of different land uses in humid subtropical ecosystems: from native forests to tree plantations
Land-use changes in forest ecosystems may alter the amount of carbon sequestration. The main objective of this study was to characterize the impact of different land-use practices on structure and functioning of humid subtropical forests that are under severe threat. We emphasize the characterization of canopy photosynthetic activity, assessed by the Enhanced Vegetation Index (EVI), the Leaf Area Index (LAI) and the fraction of Absorbed Photosynthetically Active Radiation (fPAR), using a combination of ground base measurements and remote sensing data on native well-preserved forests, impacted forests by selective logging and pine plantations in NE Argentina. Even though selective timber extraction resulted in a substantial decrease in stand’s tree density, EVI values were as high as those from preserved forests. In these forests, an increase in the understory cover appears to compensate the response of stand’s EVI to timber extraction. Removal of canopy trees enhances incoming solar radiation, allowing active growth of understory vegetation. The pine plantations exhibited the lowest values of LAI, fPAR and EVI. However, when EVI was normalized by LAI, the pine plantations exhibited the highest EVI/LAI values. Our results suggest that after 15 years of forest recovery from selective timber extraction, photosynthetic capacity was similar to that of preserved forests. Increases in the understory cover may compensate the potential decrease in the canopy photosynthetic activity. Pine plantations resulted in substantially lower productivity as depicted by lower EVI and LAI but exhibited higher growth efficiency than native forests.Laboratorio de Investigación de Sistemas Ecológicos y Ambientale
Fibroblast Primary Cilia are Required for Cardiac Fibrosis
Background: The primary cilium is a singular cellular structure that extends from the surface of many cell types and plays crucial roles in vertebrate development, including that of the heart. Whereas ciliated cells have been described in developing heart, a role for primary cilia in adult heart has not been reported. This, coupled with the fact that mutations in genes coding for multiple ciliary proteins underlie polycystic kidney disease, a disorder with numerous cardiovascular manifestations, prompted us to identify cells in adult heart harboring a primary cilium and to determine whether primary cilia play a role in disease-related remodeling.
Methods: Histological analysis of cardiac tissues from C57BL/6 mouse embryos, neonatal mice, and adult mice was performed to evaluate for primary cilia. Three injury models (apical resection, ischemia/reperfusion, and myocardial infarction) were used to identify the location and cell type of ciliated cells with the use of antibodies specific for cilia (acetylated tubulin, γ-tubulin, polycystin [PC] 1, PC2, and KIF3A), fibroblasts (vimentin, α-smooth muscle actin, and fibroblast-specific protein-1), and cardiomyocytes (α-actinin and troponin I). A similar approach was used to assess for primary cilia in infarcted human myocardial tissue. We studied mice silenced exclusively in myofibroblasts for PC1 and evaluated the role of PC1 in fibrogenesis in adult rat fibroblasts and myofibroblasts.
Results: We identified primary cilia in mouse, rat, and human heart, specifically and exclusively in cardiac fibroblasts. Ciliated fibroblasts are enriched in areas of myocardial injury. Transforming growth factor β-1 signaling and SMAD3 activation were impaired in fibroblasts depleted of the primary cilium. Extracellular matrix protein levels and contractile function were also impaired. In vivo, depletion of PC1 in activated fibroblasts after myocardial infarction impaired the remodeling response.
Conclusions: Fibroblasts in the neonatal and adult heart harbor a primary cilium. This organelle and its requisite signaling protein, PC1, are required for critical elements of fibrogenesis, including transforming growth factor β-1-SMAD3 activation, production of extracellular matrix proteins, and cell contractility. Together, these findings point to a pivotal role of this organelle, and PC1, in disease-related pathological cardiac remodeling and suggest that some of the cardiovascular manifestations of autosomal dominant polycystic kidney disease derive directly from myocardium-autonomous abnormalities
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