We report on the first search for atmospheric and for diffuse astrophysical neutrino-induced showers (cascades) in the IceCube detector using 257 days of data collected in the year 2007-2008 with 22 ...strings active. A total of 14 events with energies above 16 TeV remained after event selections in the diffuse analysis, with an expected total background contribution of 8.3 +/- 3.6. At 90% confidence we set an upper limit of E(2)Phi(90%CL) < 3.6 x 10(-7) GeV.cm(-2).s(-1).sr(-1) on the diffuse flux of neutrinos of all flavors in the energy range between 24 TeV and 6.6 PeV assuming that Phi proportional to E(-2) and the flavor composition of the nu(e):nu(mu):nu(tau) flux is 1:1:1 at the Earth. The atmospheric neutrino analysis was optimized for lower energies. A total of 12 events were observed with energies above 5 TeV. The observed number of events is consistent with the expected background, within the uncertainties.
Currently, there is a greater need to develop mechanical instruments that facilitate the performance of activities that involve excessive force, or those in which the human being cannot intervene ...directly because they are dangerous materials or places of risk. On the other hand, there are also some situations within the health area, where it is necessary to perform surgeries or high-precision medical care in places where medical personnel are not present.That is why this research has sought a way to contribute to society through the application of the area of knowledge of electromechanics, robotics and software engineering. This project has been conceived from the idea of developing remote-controlled robots through IoT technology.
The first dedicated search for ultrahigh-energy (UHE) tau neutrinos of astrophysical origin was performed using the IceCube detector in its 22-string configuration with an instrumented volume of ...roughly 0.25 km super(3). The search also had sensitivity to UHE electron and muon neutrinos. After application of all selection criteria to approximately 200 live-days of data, we expect a background of 0.60 + or - 0.19(stat) (ProQuest: Formulae and/or non-USASCII text omitted) events and observe three events, which after inspection, emerge as being compatible with background but are kept in the final sample. Therefore, we set an upper limit on neutrinos of all flavors from UHE astrophysical sources at 90% C.L. of (ProQuest: Formulae and/or non-USASCII text omitted) GeV cm super(-2) sr super(-1) s super(-1) over an estimated primary neutrino energy range of 340 TeV to 200 PeV.
We report on the results of the search for extremely-high energy neutrinos with energies above 107GeV obtained with the partially (˜30%) constructed IceCube in 2007. From the absence of signal events ...in the sample of 242.1 days of effective live time, we derive a 90% C.L. model independent differential upper limit based on the number of signal events per energy decade at E2ϕνe+νμ+ντ≃1.4×10-6GeVcm-2sec-1sr-1 for neutrinos in the energy range from 3×107 to 3×109GeV.
Resumo Fundamento A pandemia de COVID-19 interferiu na prestação de atendimento a doenças cardiovasculares na América Latina. No entanto, o efeito da pandemia nos volumes de procedimentos cardíacos ...diagnósticos ainda não foi quantificado. Objetivo Avaliar (1) o impacto de COVID-19 nos volumes de diagnóstico cardíaco na América Latina e (2) determinar sua relação com a incidência de casos de COVID-19 e as medidas de distanciamento social. Métodos A International Atomic Energy Agency realizou uma pesquisa mundial avaliando mudanças nos volumes diagnósticos cardíacos decorrentes da COVID-19. Foram obtidos os volumes diagnósticos cardíacos dos locais participantes para março e abril de 2020 e comparados com março de 2019. Foram coletados dados de distanciamento social a partir dos Relatórios de mobilidade da comunidade de Google e a incidência de COVID-19 por país a partir de Our World in Data. Resultados Foram realizadas pesquisas em 194 centros que realizam procedimentos diagnósticos cardíacos, em 19 países da América Latina. Em comparação com o mês de março de 2019, os volumes dos procedimentos diagnósticos cardíacos diminuíram 36% em março de 2020 e 82% em abril de 2020.As maiores reduções ocorreram em relação aos testes de estresse ecocardiográfico (91%), testes ergométricos de esteira (88%) e escore de cálcio por tomografia computadorizada (87%), com pequenas variações entre as sub-regiões da América Latina. As mudanças em padrões de distanciamento social (p < 0,001) estavam mais fortemente associadas com a redução do volume do que a incidência de COVID-19 (p = 0,003). Conclusões A COVID-19 foi associada a uma redução significativa de procedimentos diagnósticos cardíacos na América Latina, a qual foi mais relacionada ao distanciamento social do que ao aumento da incidência da COVID-19. São necessários melhor equilíbrio e timing de medidas de distanciamento social e planejamento para manter o acesso ao atendimento médico durante um surto pandêmico, especialmente em regiões com alta mortalidade cardiovascular.
The detection of acoustic signals from ultra-high energy neutrino interactions is a promising method to measure the tiny flux of cosmogenic neutrinos expected on Earth. The energy threshold for this ...process depends strongly on the absolute noise level in the target material. The South Pole Acoustic Test Setup (SPATS), deployed in the upper part of four boreholes of the IceCube Neutrino Observatory, has monitored the noise in Antarctic ice at the geographic South Pole for more than two years down to 500 m depth. The noise is very stable and Gaussian distributed. Lacking an in-situ calibration up to now, laboratory measurements have been used to estimate the absolute noise level in the 10 to 50 kHz frequency range to be smaller than 20 mPa. Using a threshold trigger, sensors of the South Pole Acoustic Test Setup registered acoustic pulse-like events in the IceCube detector volume and its vicinity. Acoustic signals from refreezing IceCube holes and from anthropogenic sources have been used to localize acoustic events. Monte Carlo simulations of sound propagating from the established sources to the SPATS sensors have allowed to check corresponding model expectations. An upper limit on the neutrino flux at energies \(E_\nu > 10^{11}\) GeV is derived from acoustic data taken over eight months.
The advent of intravitreal anti-vascular endothelial growth factor (anti-VEGF) medications has revolutionized the treatment of diabetic eye diseases. Herein, we report the outcomes of clinical ...studies carried out by the Pan-American Collaborative Retina Study Group (PACORES), with a specific focus on the efficacy of intravitreal bevacizumab in the management of diabetic macular edema and proliferative diabetic retinopathy. We will also discuss the use of intravitreal bevacizumab as a preoperative, adjuvant therapy before vitrectomy for proliferative diabetic retinopathy.
This paper describes the response of the IceCube neutrino telescope located at the geographic South Pole to outbursts of MeV neutrinos from the core collapse of nearby massive stars. IceCube was ...completed in December 2010 forming a lattice of 5160 photomultiplier tubes that monitor a volume of ~ 1 cubic kilometer in the deep Antarctic ice for particle induced photons. The telescope was designed to detect neutrinos with energies greater than 100 GeV. Owing to subfreezing ice temperatures, the photomultiplier dark noise rates are particularly low. Hence IceCube can also detect large numbers of MeV neutrinos by observing a collective rise in all photomultiplier rates on top of the dark noise. With 2 ms timing resolution, IceCube can detect subtle features in the temporal development of the supernova neutrino burst. For a supernova at the galactic center, its sensitivity matches that of a background-free megaton-scale supernova search experiment. The sensitivity decreases to 20 standard deviations at the galactic edge (30 kpc) and 6 standard deviations at the Large Magellanic Cloud (50 kpc). IceCube is sending triggers from potential supernovae to the Supernova Early Warning System. The sensitivity to neutrino properties such as the neutrino hierarchy is discussed, as well as the possibility to detect the neutronization burst, a short outbreak of electron neutrinos released by electron capture on protons soon after collapse. Tantalizing signatures, such as the formation of a quark star or a black hole as well as the characteristics of shock waves, are investigated to illustrate IceCube's capability for supernova detection.
The regulation of the Ca2+ -induced Ca2+ release (CICR) from intracellular stores is a critical step in the cardiac cycle. The inherent positive feedback of CICR should make it a self-regenerating ...process. It is accepted that CICR must be governed by some negative control, but its nature is still debated. We explore here the importance of the Ca2+ released from sarcoplasmic reticulum (SR) on the mechanisms that may control CICR. Specifically, we compared the effect of replacing Ca2+ with Sr2+ on intracellular Ca2+ signaling in intact cardiac myocytes as well as on the function of single ryanodine receptor (RyR) Ca2+ release channels in panar bilayers. In cells, both CICR and Sr2+ -induced Sr2+ release (SISR) were observed. Action potential induced Ca2+ -transients and spontaneous Ca2+ waves were considerably faster than their Sr2+ -mediated counterparts. However, the kinetics of Ca2+ and Sr2+ sparks was similar. At the single RyR channel level, the affinities of Ca2+ and Sr2+ activation were different but the affinities of Ca2+ and Sr2+ inactivation were similar. Fast Ca2+ and Sr2+ stimuli activated RyR channels equally fast but adaptation (a spontaneous slow transition back to steady-state activity levels) was not observed in the Sr2+ case. Together, these results suggest that regulation of the RyR channel by cytosolic Ca2+ is not involved in turning off the Ca2+ spark. In contrast, cytosolic Ca2+ is important in the propagation global Ca2+ release events and in this regard single RyR channel sensitivity to cytosolic Ca2+ activation, not low-affinity cytosolic Ca2+ inactivation, is a key factor. This suggests that the kinetics of local and global RyR-mediated Ca2+ release signals are affected in a distinct way by different divalent cations in cardiac muscle cells.
Self-annihilating or decaying dark matter in the Galactic halo might produce high energy neutrinos detectable with neutrino telescopes. We have conducted a search for such a signal using 276 days of ...data from the IceCube 22-string configuration detector acquired during 2007 and 2008. The effect of halo model choice in the extracted limit is reduced by performing a search that considers the outer halo region and not the Galactic Center. We constrain any large scale neutrino anisotropy and are able to set a limit on the dark matter self-annihilation cross section of <\sigma_{A}v> \simeq 10^{-22} cm^3/s for WIMP masses above 1 TeV, assuming a monochromatic neutrino line spectrum.
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