Plasma wave instabilities induced by neutrinos

Quantum field theory is applied to study the interaction of an electron plasma with an intense neutrino flux. A connection is established between the field theory results and classical kinetic theory. The dispersion relation and damping rate of the plasma longitudinal waves are derived in the presence of neutrinos. It is shown that Supernova neutrinos are never collimated enough to cause non-linear effects associated with a neutrino resonance. They only induce neutrino Landau damping, linearly proportional to the neutrino flux and $G_{\mathrm{F}}^{2}$.Comment: 18 pages, 3 figures, title and references correcte

Electron and Gamma Background in CRESST Detectors

The CRESST experiment monitors 300g CaWO_4 crystals as targets for particle interactions in an ultra low background environment. In this paper, we analyze the background spectra that are recorded by three detectors over many weeks of data taking. Understanding these spectra is mandatory if one wants to further reduce the background level, and allows us to cross-check the calibration of the detectors. We identify a variety of sources, such as intrinsic contaminations due to primordial radioisotopes and cosmogenic activation of the target material. In particular, we detect a 3.6keV X-ray line from the decay of 41-Ca with an activity of (26\pm4)\mu Bq, corresponding to a ratio 41-Ca/40-Ca=(2.2\pm0.3)\times10^{-16}.Comment: 7 pages, 12 figure

Search for an invisibly decaying Higgs boson or dark matter candidates produced in association with a Z boson in pp collisions at root s=13 TeV with the ATLAS detector

SCOAP

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Transplantation and survival of mouse inner ear progenitor/stem cells in the organ of Corti after cochleostomy of hearing-impaired guinea pigs: preliminary results

In mammals, damage to sensory receptor cells (hair cells) of the inner ear results in permanent sensorineural hearing loss. Here, we investigated whether postnatal mouse inner ear progenitor/stem cells (mIESCs) are viable after transplantation into the basal turns of neomycin-injured guinea pig cochleas. We also examined the effects of mIESC transplantation on auditory functions. Eight adult female Cavia porcellus guinea pigs (250-350g) were deafened by intratympanic neomycin delivery. After 7 days, the animals were randomly divided in two groups. The study group (n=4) received transplantation of LacZ-positive mIESCs in culture medium into the scala tympani. The control group (n=4) received culture medium only. At 2 weeks after transplantation, functional analyses were performed by auditory brainstem response measurement, and the animals were sacrificed. The presence of mIESCs was evaluated by immunohistochemistry of sections of the cochlea from the study group. Non-parametric tests were used for statistical analysis of the data. Intratympanic neomycin delivery damaged hair cells and increased auditory thresholds prior to cell transplantation. There were no significant differences between auditory brainstem thresholds before and after transplantation in individual guinea pigs. Some mIESCs were observed in all scalae of the basal turns of the injured cochleas, and a proportion of these cells expressed the hair cell marker myosin VIIa. Some transplanted mIESCs engrafted in the cochlear basilar membrane. Our study demonstrates that transplanted cells survived and engrafted in the organ of Corti after cochleostomy

Presença do arilo na produção de mudas de Maytenus ilicifolia Presence of arils over Maytenus ilicifolia seedlings production

A propagação da espinheira-santa (Maytenus ilicifolia) é feita por sementes, sendo indicada a retirada do arilo para a semeadura, prática que demanda muito tempo e mão-de-obra. O experimento foi instalado com o objetivo de avaliar a influência do arilo na produção de mudas de espinheira-santa. Foram utilizados dois acessos do Banco Ativo de Germoplasma de M. ilicifolia da Embrapa Clima Temperado, 30 e 91. Os tratamentos utilizados foram: T1 - sementes com arilo retirado logo após a abertura das cápsulas (armazenadas em câmara fria sem arilo); T2 - sementes com arilo retirado no dia da semeadura (armazenadas em câmara fria com arilo) e T3 - sementes sem a retirada do arilo. Foram avaliados: dias da semeadura à emergência (DSE); porcentagem de emergência em canteiros (%EC); comprimento da parte aérea (CPA); diâmetro da base do caule (DBC) e número de folhas/planta (NF). A presença do arilo nas sementes de M. ilicifolia não influenciou os caracteres DSE, %G, DBC e NF, podendo influenciar apenas no caráter comprimento da parte aérea, dependendo da constituição genética da população, não sendo necessária a retirada do arilo para a semeadura.<br>Maytenus ilicifolia is propagated by seeds and it is indicated to remove arils before sowing, what requires much time and work. An experiment to evaluate the influence of arils over seedlings production was installed in Embrapa Clima Temperado, in Pelotas, RS. Two accesses (30 and 91) of M. ilicifolia Gene Bank were used. The treatments were: T1 - seeds with arils removed immediately after the capsules (fruits) being opened (stored in cold room without arils); T2 - seeds with arils removed in the sowing’s day (stored in cold room with arils); T3 - seeds with arils. The characters evaluated were: days of sowing to emergence (DSE); emergence percentage (%G); aerial part length (CPA); stem base diameter (DBC) and number of leaves/seedling (NF). The arils in the seeds of M. ilicifolia did not influence the characters DSE, %G, DBC e NF, but can influence the aerial part length (CPA), depending on the population genetic constitution. It is not necessary to remove the seeds arils to sowing of M. ilicifolia