ANN-based energy reconstruction procedure for TACTIC gamma-ray telescope and its comparison with other conventional methods

The energy estimation procedures employed by different groups, for determining the energy of the primary $\gamma$-ray using a single atmospheric Cherenkov imaging telescope, include methods like polynomial fitting in SIZE and DISTANCE, general least square fitting and look-up table based interpolation. A novel energy reconstruction procedure, based on the utilization of Artificial Neural Network (ANN), has been developed for the TACTIC atmospheric Cherenkov imaging telescope. The procedure uses a 3:30:1 ANN configuration with resilient backpropagation algorithm to estimate the energy of a $\gamma$-ray like event on the basis of its image SIZE, DISTANCE and zenith angle. The new ANN-based energy reconstruction method, apart from yielding an energy resolution of $\sim$ 26%, which is comparable to that of other single imaging telescopes, has the added advantage that it considers zenith angle dependence as well. Details of the ANN-based energy estimation procedure along with its comparative performance with other conventional energy reconstruction methods are presented in the paper and the results indicate that amongst all the methods considered in this work, ANN method yields the best results. The performance of the ANN-based energy reconstruction has also been validated by determining the energy spectrum of the Crab Nebula in the energy range 1-16 TeV, as measured by the TACTIC telescope.Comment: 23pages, 9 figures Accepted for publication in NIM

Nova técnica de bloqueio do plexo braquial em cães New technique of brachial plexus block in dogs

O objetivo do presente estudo foi analisar a viabilidade e a eficácia de uma nova técnica para o bloqueio do plexo braquial em cães. Para tanto, foram utilizados 11 cães, machos e fêmeas, idade e peso variáveis e mestiços. Os animais foram pré-tratados com acepromazina e a indução da anestesia foi realizada com propofol. Posteriormente, os animais foram submetidos ao bloqueio do plexo braquial que constou da associação da técnica de múltiplas injeções com o emprego do estimulador de nervos e a técnica da palpação arterial como ponto de referência para a localização dos nervos. Utilizou-se como anestésico local, a bupivacaína com vasoconstritor administrado na dose total de 4mg/kg a 0,375% . O volume total foi dividido em 4 partes iguais, administradas na velocidade de 30 segundos cada, com o objetivo de se atingir a maior quantidade de nervos. O tempo necessário para realização da técnica foi de 11,30 ± 4,54 minutos; o período de latência para o bloqueio motor foi de 9,70 ± 5,52 minutos e para o bloqueio sensitivo foi de 26,20 ± 8,86 min. , sendo a duração da analgesia de 11:00 ± 0:45 horas. Em 90% dos animais, o bloqueio foi efetivo, constatado através da anestesia de todo membro torácico distal à articulação escápulo-umeral. A única complicação observada foi a hipotensão arterial desenvolvida em um animal. Mediante os resultados obtidos, pode-se pressupor que as cirurgias envolvendo o membro torácico distal à articulação escápulo-umeral poderão ser utilizadas com auxílio desta nova técnica do bloqueio do plexo braquial, bem como na analgesia pós-operatória de longa duração.<br>The aim of this study was to evaluate the viability and efficacy of a new technique of brachial plexus block in dogs. Eleven mongrel dogs of different ages and weight, both male and female were used. Animals were pre-medicated with acepromazine and induction of anesthesia was performed with propofol. The brachial plexus block was achieved with the combination of the following techniques: multiple injections, nerve stimulator and the axilary artery pulse to locate the nerves. Bupivacaine was the local anesthetic employed at a total dose of 4mg/kg. This dose was divided in 4, that were administered in 30 seconds each, to achieve more nerves as possible. The time spent to perform the whole procedure was 11.30 ± 4.54 minutes; onset time for motor and sensitive block were 9.70 ± 5.52 and 26.20 ± 8.86 respectively. Duration of analgesia was 11.0 ± 0.45 hours. The block was effective in 90% of animals what was assessed through complete anesthesia of the front limb distally to the shoulder joint. Hypotension in one animal was the sole complication observed. With the results obtained we can suggest the use of this technique for front limb surgery performed distally to the shoulder joint as well as a pos-operative analgesic approach in dogs

Measurement of tau branching ratios

Using the data accumulated at LEP in 1989 and 1990 with the ALEPH detector, the inclusive and exclusive branching ratios of the τ lepton have been measured assuming lepton universality inZ0 decays. The inclusive branching fractions for the τ decay into one, three, and five charged particles have been determined to be (85.45±0.97)%, (14.35±0.48)%, and (0.10±0.05)%, respectively, in agreement with the world averages. New undetected decay modes are determined to have a branching fraction of less than 2.1% at 95% CL. The measured branching ratios for quasi-exclusive channels are slightly larger than, but consistent with the world averages, except for the modes τ→3 hadrons+vτ andτ→hadron+2π0vτ, which are significantly larger. These latter branching ratios have been found to be (9.5±0.7)% and (10.2±1.1)%, respectively. The sum of all the measured quasi-exclusive branching ratios is (100.4±1.8)%. A fully exclusive analysis of modes with neutral pions shows no evidence for new photonic decay modes with a branching fraction limit of 3.4% at 95% CL

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit. © 2023. The Author(s). Published by IOP Publishing Ltd on behalf of the Astronomical Society of the Pacific (ASP). All rights reserved.Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]