16,157 research outputs found
Unitarity of the Leptonic Mixing Matrix
We determine the elements of the leptonic mixing matrix, without assuming
unitarity, combining data from neutrino oscillation experiments and weak
decays. To that end, we first develop a formalism for studying neutrino
oscillations in vacuum and matter when the leptonic mixing matrix is not
unitary. To be conservative, only three light neutrino species are considered,
whose propagation is generically affected by non-unitary effects. Precision
improvements within future facilities are discussed as well.Comment: Standard Model radiative corrections to the invisible Z width
included. Some numerical results modified at the percent level. Updated with
latest bounds on the rare tau decay. Physical conculsions unchange
Recent Technological Developments on LGAD and iLGAD Detectors for Tracking and Timing Applications
This paper reports the last technological development on the Low Gain
Avalanche Detector (LGAD) and introduces a new architecture of these detectors
called inverse-LGAD (iLGAD). Both approaches are based on the standard
Avalanche Photo Diodes (APD) concept, commonly used in optical and X-ray
detection applications, including an internal multiplication of the charge
generated by radiation. The multiplication is inherent to the basic n++-p+-p
structure, where the doping profile of the p+ layer is optimized to achieve
high field and high impact ionization at the junction. The LGAD structures are
optimized for applications such as tracking or timing detectors for high energy
physics experiments or medical applications where time resolution lower than 30
ps is required. Detailed TCAD device simulations together with the electrical
and charge collection measurements are presented through this work.Comment: Keywords: silicon detectors, avalanche multiplication, timing
detectors, tracking detectors. 8 pages. 8 Figure
Myristic acid potentiates palmitic acid-induced lipotoxicity and steatohepatitis associated with lipodystrophy by sustaning de novo ceramide synthesis.
Palmitic acid (PA) induces hepatocyte apoptosis and fuels de novo ceramide synthesis in the endoplasmic reticulum (ER). Myristic acid (MA), a free fatty acid highly abundant in copra/palmist oils, is a predictor of nonalcoholic steatohepatitis (NASH) and stimulates ceramide synthesis. Here we investigated the synergism between MA and PA in ceramide synthesis, ER stress, lipotoxicity and NASH. Unlike PA, MA is not lipotoxic but potentiated PA-mediated lipoapoptosis, ER stress, caspase-3 activation and cytochrome c release in primary mouse hepatocytes (PMH). Moreover, MA kinetically sustained PA-induced total ceramide content by stimulating dehydroceramide desaturase and switched the ceramide profile from decreased to increased ceramide 14:0/ceramide16:0, without changing medium and long-chain ceramide species. PMH were more sensitive to equimolar ceramide14:0/ceramide16:0 exposure, which mimics the outcome of PA plus MA treatment on ceramide homeostasis, than to either ceramide alone. Treatment with myriocin to inhibit ceramide synthesis and tauroursodeoxycholic acid to prevent ER stress ameliorated PA plus MA induced apoptosis, similar to the protection afforded by the antioxidant BHA, the pan-caspase inhibitor z-VAD-Fmk and JNK inhibition. Moreover, ruthenium red protected PMH against PA and MA-induced cell death. Recapitulating in vitro findings, mice fed a diet enriched in PA plus MA exhibited lipodystrophy, hepatosplenomegaly, increased liver ceramide content and cholesterol levels, ER stress, liver damage, inflammation and fibrosis compared to mice fed diets enriched in PA or MA alone. The deleterious effects of PA plus MA-enriched diet were largely prevented by in vivo myriocin treatment. These findings indicate a causal link between ceramide synthesis and ER stress in lipotoxicity, and imply that the consumption of diets enriched in MA and PA can cause NASH associated with lipodystrophy
Solid and Aqueous Speciation of Yttrium in Passive Remediation Systems of Acid Mine Drainage
International audienceYttrium belongs to the rare earth elements (REEs) together with lanthanides and scandium. REEs are commonly used in modern technologies, and their limited supply has made it necessary to look for new alternative resources. Acid mine drainage (AMD) is a potential resource since it is moderately enriched in REEs. In fact, in passive remediation systems, which are implemented to minimize the environmental impacts of AMD, REEs are mainly retained in basaluminite, an aluminum hydroxysulfate precipitate. In this study, the solid and liquid speciation and the local structure of yttrium are studied in high-sulfate aqueous solutions, basaluminite standards, and samples from remediation columns using synchrotron-based techniques and molecular modeling. Pair distribution function (PDF) analyses and ab initio molecular dynamics density functional theory models of the yttrium sulfate solution show that the YSO4+ ion pair forms a monodentate inner-sphere complex. Extended X-ray absorption fine structure (EXAFS) and PDF analyses show that Y is retained by basaluminite, forming a monodentate inner-sphere surface complex on the aluminum hydroxide surface. EXAFS of the column samples shows that more than 72% of their signal is represented by the signal of basaluminite with which YSO4+ forms an inner-sphere complex. The atomic view of the REE configuration in AMD environments could facilitate a deeper research of REE recovery from waste generated in AMD remediation systems
EURONU WP6 2009 yearly report: Update of the physics potential of Nufact, superbeams and betabeams
Many studies in the last ten years have shown that we can measure the unknown
angle theta13, discover leptonic CP violation and determine the neutrino
hierarchy in more precise neutrino oscillation experiments, searching for the
subleading channel nue -> numu in the atmospheric range. In this first report
of WP6 activities the following new results are reviewed: (1) Re-evaluation of
the physics reach of the upcoming generation of experiments to measure theta13
and delta; (2) New tools to explore a larger parameter space as needed beyond
the standard scenario; (3) Neutrino Factory: (a) evaluation of the physics
reach of a Nufact regards sterile neutrinos; (b) evaluation of the physics
reach of a Nufact as regards non-standard interactions; (c) evaluation of the
physics reach of a Nufact as regards violation of unitarity; (d) critical
assessment on long baseline tau-detection at Nufact; (e) new physics searches
at a near detector in a Nufact; (4) Beta-beams: (a) choice of ions and location
for a gamma = 100 CERN-based beta-beam; (b) re-evaluation of atmospheric
neutrino background for the gamma = 100 beta-beam scenario; (c) study of a two
baseline beta-beam; (d) measuring absolute neutrino mass with beta-beams; (e)
progress on monochromatic beta-beams; (5) Update of the physics potential of
the SPL super-beam. Eventually, we present an updated comparison of the
sensitivity to theta13, delta and the neutrino mass hierarchy of several of the
different proposed facilities.Comment: 2009 Yearly report of the Working Package 6 (Physics) of the EUROnu
FP7 EU project. 55 pages, 21 figures
COVID-19 and Sick Leave: An Analysis of the Ibermutua Cohort of Over 1,651,305 Spanish Workers in the First Trimester of 2020
Objectives: The worldwide SARS-COV2 pandemic has impacted the health of workers and companies. The aim is to quantify it according to sick leave. Methods: Using ICD-9 codes, we analyzed Ibermutua records of all sick leaves during the first trimester of 2020, compared to during the same months of 2017, 2018, and 2019. We stratified the analysis by causes, patient sex, activity sectors, and regional data. All sick leaves were adjusted by the number of Ibermutua-affiliated persons in each period. Results: In March 2020, there was an unprecedented (116%) increase in total sick leaves, mainly due to infectious and respiratory diseases. Men and women were equally affected. All activity sectors were impacted, with the highest increase (457%) observed among health-related workers, especially due to contagious disease. The incidences of sick leaves were heterogeneous among different regions. Cost-analysis of sick leaves during the first trimester of 2020 compared with in previous years showed 40.3% increment (mean 2,813 vs. 2,005 euro per 100 affiliated workers). Conclusions: The SARS-COV2 pandemic is having a huge impact on workers' health, as shown by data regarding sick leaves in March 2020. This is associated with greater economic burden for companies, both due to the cost associated with sick leaves and the losses in productivity due to confinement
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