855 research outputs found

    Low delta-V near-Earth asteroids: A survey of suitable targets for space missions

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    In the last decades Near-Earth Objects (NEOs) have become very important targets to study, since they can give us clues to the formation, evolution and composition of the Solar System. In addition, they may represent either a threat to humankind, or a repository of extraterrestrial resources for suitable space-borne missions. Within this framework, the choice of next-generation mission targets and the characterisation of a potential threat to our planet deserve special attention. To date, only a small part of the 11,000 discovered NEOs have been physically characterised. From ground and space-based observations one can determine some basic physical properties of these objects using visible and infrared spectroscopy. We present data for 13 objects observed with different telescopes around the world (NASA-IRTF, ESO-NTT, TNG) in the 0.4 - 2.5 um spectral range, within the NEOSURFACE survey (http://www.oa-roma.inaf.it/planet/NEOSurface.html). Objects are chosen from among the more accessible for a rendez-vous mission. All of them are characterised by a delta-V (the change in velocity needed for transferring a spacecraft from low-Earth orbit to rendez-vous with NEOs) lower than 10.5 km/s, well below the Solar System escape velocity (12.3 km/s). We taxonomically classify 9 of these objects for the first time. 11 objects belong to the S-complex taxonomy; the other 2 belong to the C-complex. We constrain the surface composition of these objects by comparing their spectra with meteorites from the RELAB database. We also compute olivine and pyroxene mineralogy for asteroids with a clear evidence of pyroxene bands. Mineralogy confirms the similarity with the already found H, L or LL ordinary chondrite analogues.Comment: 9 pages, 7 figures, to be published in A&A Minor changes by language edito

    TB STIGMA – MEASUREMENT GUIDANCE

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    TB is the most deadly infectious disease in the world, and stigma continues to play a significant role in worsening the epidemic. Stigma and discrimination not only stop people from seeking care but also make it more difficult for those on treatment to continue, both of which make the disease more difficult to treat in the long-term and mean those infected are more likely to transmit the disease to those around them. TB Stigma – Measurement Guidance is a manual to help generate enough information about stigma issues to design and monitor and evaluate efforts to reduce TB stigma. It can help in planning TB stigma baseline measurements and monitoring trends to capture the outcomes of TB stigma reduction efforts. This manual is designed for health workers, professional or management staff, people who advocate for those with TB, and all who need to understand and respond to TB stigma

    Electron/pion separation with an Emulsion Cloud Chamber by using a Neural Network

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    We have studied the performance of a new algorithm for electron/pion separation in an Emulsion Cloud Chamber (ECC) made of lead and nuclear emulsion films. The software for separation consists of two parts: a shower reconstruction algorithm and a Neural Network that assigns to each reconstructed shower the probability to be an electron or a pion. The performance has been studied for the ECC of the OPERA experiment [1]. The e/πe/\pi separation algorithm has been optimized by using a detailed Monte Carlo simulation of the ECC and tested on real data taken at CERN (pion beams) and at DESY (electron beams). The algorithm allows to achieve a 90% electron identification efficiency with a pion misidentification smaller than 1% for energies higher than 2 GeV

    Emulsion sheet doublets as interface trackers for the OPERA experiment

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    New methods for efficient and unambiguous interconnection between electronic counters and target units based on nuclear photographic emulsion films have been developed. The application to the OPERA experiment, that aims at detecting oscillations between mu neutrino and tau neutrino in the CNGS neutrino beam, is reported in this paper. In order to reduce background due to latent tracks collected before installation in the detector, on-site large-scale treatments of the emulsions ("refreshing") have been applied. Changeable Sheet (CSd) packages, each made of a doublet of emulsion films, have been designed, assembled and coupled to the OPERA target units ("ECC bricks"). A device has been built to print X-ray spots for accurate interconnection both within the CSd and between the CSd and the related ECC brick. Sample emulsion films have been extensively scanned with state-of-the-art automated optical microscopes. Efficient track-matching and powerful background rejection have been achieved in tests with electronically tagged penetrating muons. Further improvement of in-doublet film alignment was obtained by matching the pattern of low-energy electron tracks. The commissioning of the overall OPERA alignment procedure is in progress.Comment: 19 pages, 19 figure

    First events from the CNGS neutrino beam detected in the OPERA experiment

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    The OPERA neutrino detector at the underground Gran Sasso Laboratory (LNGS) was designed to perform the first detection of neutrino oscillations in appearance mode, through the study of nu_mu to nu_tau oscillations. The apparatus consists of a lead/emulsion-film target complemented by electronic detectors. It is placed in the high-energy, long-baseline CERN to LNGS beam (CNGS) 730 km away from the neutrino source. In August 2006 a first run with CNGS neutrinos was successfully conducted. A first sample of neutrino events was collected, statistically consistent with the integrated beam intensity. After a brief description of the beam and of the various sub-detectors, we report on the achievement of this milestone, presenting the first data and some analysis results.Comment: Submitted to the New Journal of Physic

    Healthcare utilization among aging Latvians with diminished activities of daily living : Ieva Reine

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    The population in Latvia is aging. Independence in performing activities of daily living (ADL) is a core aspect of functioning, and the elderly frequently experience limitations in functioning. Little is known about the utilization of healthcare of elderly Latvians with functional difficulties. The purpose of this study was to determine the relationship between functional difficulties and utilization of healthcare among the elderly in Latvia. This study had three overall objectives: (i) to investigate the determinants of utilization of health care for elderly Latvians with functional difficulties; (ii) examine the relationship between predisposing characteristics, enabling resources, and need with specific measures of access to care using the Behavioral Model for Vulnerable Populations and to (iii) identify the nature and existence of health disparities among the elderly in Latvia, with and without functional difficulties. Data from the 2017 Survey of Health, Ageing and Retirement in Europe (SHARE) survey, with a sample size of 1479 was utilized. There was a statistically significant difference in the utilization of healthcare between individuals with and without functional disabilities (F(4,1) =759.615, p < 0.01), with a higher utilization of healthcare among individuals with functional difficulties (p< .01). The results of Automatic Linear Modeling indicate that significant (p < 0.05) factors in predicting utilization of healthcare include factors such as age, public sickness benefit and disability pension, and overall health status. This study is significant because it fills critical gaps in knowledge that exist with respect to healthcare utilization for elderly Latvians with functional disabilities.publishersversionPeer reviewe

    Measurement of the atmospheric muon charge ratio with the OPERA detector

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    The OPERA detector at the Gran Sasso underground laboratory (LNGS) was used to measure the atmospheric muon charge ratio in the TeV energy region. We analyzed 403069 atmospheric muons corresponding to 113.4 days of livetime during the 2008 CNGS run. We computed separately the muon charge ratio for single and for multiple muon events in order to select different energy regions of the primary cosmic ray spectrum and to test the charge ratio dependence on the primary composition. The measured charge ratio values were corrected taking into account the charge-misidentification errors. Data have also been grouped in five bins of the "vertical surface energy". A fit to a simplified model of muon production in the atmosphere allowed the determination of the pion and kaon charge ratios weighted by the cosmic ray energy spectrum.Comment: 14 pages, 10 figure

    Multi-method analysis of gender differences in psychological distress among the elderly during COVID : Ieva Reine

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    As COVID swept through Europe, and the world, with high rates of illness and death, so did symptoms of anxiety, depression, post-traumatic stress disorder, stress, and psychological distress. This study examines the relationship between gender and psychological distress among Latvians over 50 years old within the first 6 months of the COVID-19 pandemic. Data from Wave 8 COVID-19 data of the Survey of Health, Aging, and Retirement in Europe (SHARE) as an early data version of the SHARE Corona survey conducted between June and August 2020. It features the data collected by telephone (CATI) on topics related to COVID-19 for a large sub-sample of SHARE panel respondents. This study examined a sample of 980 adults over 50 years old in Latvia. Bivariate analysis were performed utilizing the Pearson chi-square test for association to examine differences in symptoms of psychological distress by gender during the first six months of the COVID-19 pandemic. Level of significance was determined by the p-value test statistic. Alpha level was established at .05. A chi-square test for association shows that there were statistically relationships between gender and feeling nervous (X2 (2, N = 976) = 22.11, p < .001), feeling depressed (X2 (3, N = 976) = 10.95, p < .01), and trouble sleeping (X2 (2, N = 976) = 20.40, p < .001). This study rejects the null hypothesis that no differences exist between the genders, as women reported greater psychological distress during the first 6 months of the COVID-19 pandemic. Additional multi-method analysis is consistent with these findings and concludes that this is due to the greater concern women report for family, and the burden which placed limitations on meeting their children and grandchildren.publishersversionPeer reviewe

    Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6 x 10(20) protons on target

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    111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee comments111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee comments111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee commentsWe thank the J-PARC staff for superb accelerator performance and the CERN NA61/SHINE Collaboration for providing valuable particle production data. We acknowledge the support of MEXT, Japan; NSERC, NRC, and CFI, Canada; CEA and CNRS/IN2P3, France; DFG, Germany; INFN, Italy; National Science Centre (NCN), Poland; RSF, RFBR and MES, Russia; MINECO and ERDF funds, Spain; SNSF and SER, Switzerland; STFC, UK; and the U. S. Deparment of Energy, USA. We also thank CERN for the UA1/NOMAD magnet, DESY for the HERA-B magnet mover system, NII for SINET4, the WestGrid and SciNet consortia in Compute Canada, GridPP, UK, and the Emerald High Performance Computing facility in the Centre for Innovation, UK. In addition, participation of individual researchers and institutions has been further supported by funds from ERC (FP7), EU; JSPS, Japan; Royal Society, UK; and DOE Early Career program, USA
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