336 research outputs found
Novel Single Photon Detectors for UV Imaging
There are several applications which require high position resolution UV
imaging. For these applications we have developed and successfully tested a new
version of a 2D UV single photon imaging detector based on a microgap RPC. The
main features of such a detectors is the high position resolution - 30 micron
in digital form and the high quantum efficiency (1-8% in the spectral interval
of 220-140 nm). Additionally, they are spark- protected and can operate without
any feedback problems at high gains, close to a streamer mode. In attempts to
extend the sensitivity of RPCs to longer wavelengths we have successfully
tested the operation of the first sealed parallel-plate gaseous detectors with
CsTe photocathodes. Finally, the comparison with other types of photosensitive
detectors is given and possible fields of applications are identified.Comment: Presented at the 5th International Workshop on RICH detectors Playa
del Carmen, Mexico, November 200
Determining the azimuthal properties of coronal mass ejections from multi-spacecraft remote-sensing observations with stereo secchi
We discuss how simultaneous observations by multiple heliospheric imagers can
provide some important information about the azimuthal properties of Coronal
Mass Ejections (CMEs) in the heliosphere. We propose two simple models of CME
geometry that can be used to derive information about the azimuthal deflection
and the azimuthal expansion of CMEs from SECCHI/HI observations. We apply these
two models to four CMEs well-observed by both STEREO spacecraft during the year
2008. We find that in three cases, the joint STEREO-A and B observations are
consistent with CMEs moving radially outward. In some cases, we are able to
derive the azimuthal cross-section of the CME fronts, and we are able to
measure the deviation from self-similar evolution. The results from this
analysis show the importance of having multiple satellites dedicated to space
weather forecasting, for example in orbits at the Lagrangian L4 and L5 points.Comment: 7 pages, 4 figures, 1 table, accepted to Ap
Report on an international workshop on kangaroo mother care: lessons learned and a vision for the future.
Globally, complications of prematurity are the leading cause of death in children under five. Preterm infants who survive their first month of life are at greater risk for various diseases and impairments in infancy, childhood and later life, representing a heavy social and economic burden for families, communities and health and social systems. Kangaroo mother care (KMC) is recommended as a beneficial and effective intervention for improving short- and long-term preterm birth outcomes in low- and high-income settings. Nevertheless, KMC is not as widely used as it should be. The International Network on KMC runs biennial workshops and congresses to help improve the coverage and quality of KMC worldwide. This paper reports the results of the two-day workshop held in November 2016, where 92 participants from 33 countries shared experiences in a series of round tables, group work sessions and plenaries.
Barriers to and enablers of KMC are discussed with regard to parents, health workers and the health system. Key factors for effective implementation and uptake relate to appropriate training for health staff, adherence to protocols and the creation of a welcoming environment for families. Recommendations for planning for national programmes are made according to a six-stage change model. Resources and the cost of making progress are discussed in terms of investment, maintenance, and acceleration and scaling-up costs. KMC training requirements are presented according to three levels of care. To ensure quality KMC, key requisites are proposed for the different KMC components and for sensitive communication with caregivers. The group attending to the monitoring and evaluation of KMC at a national and subnational level highlight the lack of standard indicator definitions. Key priorities for investment include health services research, harmonisation of indicators, development of a costing tool, programming and scaling up, and the follow-up of preterm infants.
It is hoped that this report will help to further scale-up and sustain KMC through a systematic approach that includes raising commitment, identifying key strategies to address the main barriers and using existing facilitators, ensuring training and quality, agreeing on indicators for monitoring and evaluation, and advancing implementation research
Charge amplification concepts for direction-sensitive dark matter detectors
Direction measurement of weakly interacting massive particles in
time-projection chambers can provide definite evidence of their existence and
help to determine their properties. This article demonstrates several concepts
for charge amplification in time-projection chambers that can be used in
direction-sensitive dark matter search experiments. We demonstrate
reconstruction of the 'head-tail' effect for nuclear recoils above 100keV, and
discuss the detector performance in the context of dark matter detection and
scaling to large detector volumes.Comment: 15 pages, 9 figure
Position Reconstruction in Drift Chambers operated with Xe, CO2 (15%)
We present measurements of position and angular resolution of drift chambers
operated with a Xe,CO(15%) mixture. The results are compared to Monte Carlo
simulations and important systematic effects, in particular the dispersive
nature of the absorption of transition radiation and non-linearities, are
discussed. The measurements were carried out with prototype drift chambers of
the ALICE Transition Radiation Detector, but our findings can be generalized to
other drift chambers with similar geometry, where the electron drift is
perpendicular to the wire planes.Comment: 30 pages, 18 figure
Experimental search for the LSND anomaly with the ICARUS detector in the CNGS neutrino beam
We report an early result from the ICARUS experiment on the search for nu_mu
to nu_e signal due to the LSND anomaly. The search was performed with the
ICARUS T600 detector located at the Gran Sasso Laboratory, receiving CNGS
neutrinos from CERN at an average energy of about 20 GeV, after a flight path
of about 730 km. The LSND anomaly would manifest as an excess of nu_e events,
characterized by a fast energy oscillation averaging approximately to
sin^2(1.27 Dm^2_new L/ E_nu) = 1/2. The present analysis is based on 1091
neutrino events, which are about 50% of the ICARUS data collected in 2010-2011.
Two clear nu_e events have been found, compared with the expectation of 3.7 +/-
0.6 events from conventional sources. Within the range of our observations,
this result is compatible with the absence of a LSND anomaly. At 90% and 99%
confidence levels the limits of 3.4 and 7.3 events corresponding to oscillation
probabilities of 5.4 10^-3 and 1.1 10^-2 are set respectively. The result
strongly limits the window of open options for the LSND anomaly to a narrow
region around (Dm^2, sin^2(2 theta))_new = (0.5 eV^2, 0.005), where there is an
overall agreement (90% CL) between the present ICARUS limit, the published
limits of KARMEN and the published positive signals of LSND and MiniBooNE
Collaborations.Comment: 10 pages, 7 figure
The Drift Chambers Of The Nomad Experiment
We present a detailed description of the drift chambers used as an active
target and a tracking device in the NOMAD experiment at CERN. The main
characteristics of these chambers are a large area, a self supporting structure
made of light composite materials and a low cost. A spatial resolution of 150
microns has been achieved with a single hit efficiency of 97%.Comment: 42 pages, 26 figure
Perception and practice of Kangaroo Mother Care after discharge from hospital in Kumasi, Ghana: A longitudinal study
BACKGROUND: The practice of Kangaroo Mother Care (KMC) is life saving in babies weighing less than 2000 g. Little is known about mothers' continued unsupervised practice after discharge from hospitals. This study aimed to evaluate its in-hospital and continued practice in the community among mothers of low birth weight (LBW) infants discharged from two hospitals in Kumasi, Ghana. METHODS: A longitudinal study of 202 mothers and their inpatient LBW neonates was conducted from November 2009 to May 2010. Mothers were interviewed at recruitment to ascertain their knowledge of KMC, and then oriented on its practice. After discharge, the mothers reported at weekly intervals for four follow up visits where data about their perceptions, attitudes and practices of KMC were recorded. A repeated measure logistic regression analysis was done to assess variability in the binary responses at the various reviews visits. RESULTS: At recruitment 23 (11.4%, 95%CI: 7.4 to 16.6%) mothers knew about KMC. At discharge 95.5% were willing to continue KMC at home with 93.1% willing to practice at night. 95.5% thought KMC was beneficial to them and 96.0% beneficial to their babies. 98.0% would recommend KMC to other mothers with 71.8% willing to practice KMC outdoors.At first follow up visit 99.5% (181) were still practicing either intermittent or continuous KMC. This proportion did not change significantly over the four weeks (OR: 1.4, 95%CI: 0.6 to 3.3, p-value: 0.333). Over the four weeks, increasingly more mothers practiced KMC at night (OR: 1.7, 95%CI: 1.2 to 2.6, p = 0.005), outside their homes (OR: 2.4, 95%CI: 1.7 to 3.3, p < 0.001) and received spousal help (OR: 1.6, 95%CI: 1.1 to 2.4, p = 0.007). Household chores and potentially negative community perceptions of KMC did not affect its practice with odds of 0.8 (95%CI: 0.5 to 1.2, p = 0.282) and 1.0 (95%CI: 0.6 to 1.7, p = 0.934) respectively. During the follow-up period the neonates gained 23.7 sg (95%CI: 22.6 g to 24.7 g) per day. CONCLUSION: Maternal knowledge of KMC was low at outset. Once initiated mothers continued practicing KMC in hospital and at home with their infants gaining optimal weight. Continued KMC practice was not affected by perceived community attitudes
Prematurity, executive functions and quality of parental care: a systematic review
Este artigo de revisão visa contextualizar o desenvolvimento das funções executivas (FE) em crianças prematuras, com especial atenção para o efeito dos cuidados parentais. As principais bases eletrônicas foram utilizadas para essa revisão: 31 estudos originais, duas meta-análises, uma meta-síntese e dois artigos de revisão foram identificados. Concluiu-se que as crianças prematuras têm maior risco de disfunção executiva global, sendo a qualidade dos cuidados parentais fundamentais para a modulação das FE, nomeadamente no que concerne às variáveis socioemocionais da interação, como a sensibilidadematerna. Salientam-se ainda as principais limitações dos estudos analisados e apontam-se recomendações para futura investigação sobre os efeitos dos cuidados parentais no desenvolvimento de FE em crianças prematuras.This review article aims to contextualize the development of executive functions (EF) in preterm children with special attention to the effects of parental care. The main electronic databases were used for this review: 31 original studies, two meta-analyses, one meta-synthesis and two systematic reviews were identified. The results showed that preterm infants are at risk for global executive dysfunction,and that the quality of parenting impacts the development of EF, mainly in terms of interactive socio-emotional variables, like maternal sensitivity.Finally, the main limitations of the analyzed studies are pointed out, and recommendations of future research about the effects of parental care in the development of EF in preterm children are offered.(undefined)info:eu-repo/semantics/publishedVersio
Determination of the neutron fluence, the beam characteristics and the backgrounds at the CERN-PS TOF facility
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