825 research outputs found
LATTES: a novel detector concept for a gamma-ray experiment in the Southern hemisphere
The Large Array Telescope for Tracking Energetic Sources (LATTES), is a novel
concept for an array of hybrid EAS array detectors, composed of a Resistive
Plate Counter array coupled to a Water Cherenkov Detector, planned to cover
gamma rays from less than 100 GeV up to 100 TeVs. This experiment, to be
installed at high altitude in South America, could cover the existing gap in
sensitivity between satellite and ground arrays.
The low energy threshold, large duty cycle and wide field of view of LATTES
makes it a powerful tool to detect transient phenomena and perform long term
observations of variable sources. Moreover, given its characteristics, it would
be fully complementary to the planned Cherenkov Telescope Array (CTA) as it
would be able to issue alerts.
In this talk, a description of its main features and capabilities, as well as
results on its expected performance, and sensitivity, will be presented.Comment: Proceedings of the 35th International Cosmic Ray Conference
(ICRC2017), Busan, South Korea. Presented by R. Concei\c{c}\~{a}o. 8 pages;
v2: correct affiliation + journal referenc
LATTES: A new gamma-ray detector concept for South America
Currently the detection of Very High Energy gamma-rays for astrophysics rely on the measurement of the Extensive Air Showers (EAS) either using Cherenkov detectors or EAS arrays with larger field of views but also larger energy thresholds. In this talk we present a novel hybrid detector concept for a EAS array with an improved sensitivity in the lower energies (~ 100 GeV). We discuss its main features, capabilities and present preliminary results on its expected perfomances and sensitivities.This wide field of view experiment is planned to be installed at high altitude in South America making it a complementary project to the planned Cherenkov telescope experiments and a powerful tool to trigger further observations of variable sources and to detect transients phenomena
Criminological and Medico-legal Aspects in Homicidal and Suicidal Sharp Force Fatalities
The interpretation of sharp force fatality dynamics may be difficult in some cases, but a contribution to analysis of the phenomenon may be provided by case studies. Therefore, the purpose of our study is focused on identifying, in observed sharp force fatalities, reliable parameters that can differentiate a homicidal and suicidal manner of death, with particular reference to criminological parameters. Data derived from sharp force fatality cases in Padua and Venice from 1997 to 2019, anonymized and collected in Excel, included personal, circumstantial, clinical, and psychopathological\u2013criminological data, as well as crime scene investigation, necroscopic, and toxicological data. Statistical analyses were performed using chi-square and Wilcoxon rank-sum tests. Possible predictors of homicide were analyzed by logistic regression. Six parameters (bloodstains distant from the body, clothing lacerations, hesitation/defense wounds, number of injuries, and potential motives) were significantly different in the two groups (p\ua0<\ua00.05). An independent statistical association between potential motives explaining the crime (p\ua0<\ua00.001; OR 27.533) and homicide on multiple logistic regression analysis was highlighted. The absence of clothing lacerations was inversely related to homicide (p\ua0=\ua00.002, OR 0.092). To the best of our knowledge, this is one of very few Italian studies concerning the differential diagnosis between homicidal and suicidal sharp force fatalities. The dynamics of the event is established in most cases by the integrated evaluation of data from crime scene investigation and the autopsy. Nevertheless, in an atypical scenario, a psychopathological\u2013criminological analysis may provide essential elements, and particular attention should be given to the identification of potential explanatory motives
A novel background reduction strategy for high level triggers and processing in gamma-ray Cherenkov detectors
Gamma ray astronomy is now at the leading edge for studies related both to
fundamental physics and astrophysics. The sensitivity of gamma detectors is
limited by the huge amount of background, constituted by hadronic cosmic rays
(typically two to three orders of magnitude more than the signal) and by the
accidental background in the detectors. By using the information on the
temporal evolution of the Cherenkov light, the background can be reduced. We
will present here the results obtained within the MAGIC experiment using a new
technique for the reduction of the background. Particle showers produced by
gamma rays show a different temporal distribution with respect to showers
produced by hadrons; the background due to accidental counts shows no
dependence on time. Such novel strategy can increase the sensitivity of present
instruments.Comment: 4 pages, 3 figures, Proc. of the 9th Int. Syposium "Frontiers of
Fundamental and Computational Physics" (FFP9), (AIP, Melville, New York,
2008, in press
The search for DM in nearby dSph galaxies with MAGIC: candidates, results and prospects
At present, dwarf spheroidal galaxies satellites of the Milky Way may
represent the best astrophysical objects for dark matter (DM) searches with
gamma-ray telescopes. They present the highest mass-to-light ratios known in
the Universe. Furthermore, many of them are near enough from the Earth to be
able to yield high predicted DM annihilation fluxes that might be observed by
current gamma-ray instruments like MAGIC. The picture has become even better
with the recent discovery of new dwarfs. These new objects are expected to
yield even higher DM annihilation fluxes, since most of them are nearer than
the previously known dwarfs and are even more DM dominated systems. Here a
tentative list of the best candidates is given. The observational results
obtained with MAGIC from the Draco dwarf as well as the observation of other
dwarfs carried out by other Cherenkov telescopes are presented as well.
Finally, we discuss the detection prospects of such kind of objects in the
context of DM searches.Comment: To appear in the proceedings of the 8th UCLA Dark Matter Symposium,
Marina del Rey, USA, 20-22 February 200
Dark Matter signals from Draco and Willman 1: Prospects for MAGIC II and CTA
The next generation of ground-based Imaging Air Cherenkov Telescopes (IACTs)
will play an important role in indirect dark matter searches. In this article,
we consider two particularly promising candidate sources for dark matter
annihilation signals, the nearby dwarf galaxies Draco and Willman 1, and study
the prospects of detecting such a signal for the soon-operating MAGIC II
telescope system as well as for the planned installation of CTA, taking special
care of describing the experimental features that affect the detectional
prospects. For the first time in such a study, we fully take into account the
effect of internal bremsstrahlung, which has recently been shown to
considerably enhance, in some cases, the gamma-ray flux at the high energies
where Atmospheric Cherenkov Telescopes operate, thus leading to significantly
harder annihilation spectra than traditionally considered. While the detection
of the spectral features introduced by internal bremsstrahlung would constitute
a smoking gun signature for dark matter annihilation, we find that for most
models the overall flux still remains at a level that will be challenging to
detect unless one adopts rather (though by no means overly) optimistic
astrophysical assumptions about the distribution of dark matter in the dwarfs.Comment: 10 pages, 4 figures, minor changes, matches the published version
(JCAP
Validação de variedades de milho em propriedades familiares no Rio Grande do Sul, na safra 2002/2003.
Design of a SiPM-based cluster for the Large Size Telescope camera of CTA
A Silicon Photomultiplier (SiPM)-based photodetector is being built to
demonstrate its feasibility for an alternative silicon-based camera design for
the Large Size Telescope (LST) of the Cherenkov Telescope Array. It has been
designed to match the size of the standard Photomultiplier Tube (PMT) cluster
unit and to be compatible with mechanics, electronics and focal plane optics of
the first LST camera. Here, we describe the overall SiPM cluster design along
with the main differences with respect to the currently used PMT cluster unit.
The fast electronics of the SiPM pixel and its layout are also presented. In
order to derive the best working condition for the final unit, we measured the
SiPM performances in terms of gain, photo-detection efficiency and cross-talk.
One pixel, a unit of 14 SiPMs, has been built. We will discuss also some
preliminary results regarding this device and we will highlight the future
steps of this project.Comment: submitted to NIM
Aproximação entre pesquisa e assistência técnica, com base no método treino & visita.
Neste inicio do século XXI, numerosas mudanças tem ocorrido no ambiente de transferência de tecnologia relacionado à agricultura do Rio Grande do Sul. Novos atores da iniciativa privada tomaram-se indutores do uso de práticas e tecnologias, articuladas com a venda de insumos e a compra da produção, além do avanço da informalidade no setor de sementes. No entanto, a pesquisa agropecuária continua desenvolvendo conhecimentos e tecnologias para a extensão rural oficial e privada. Nesse sentido, foi desenvolvida Uma ação da Embrapa Trigo, em parceria com a Emater/RS - Ascar, cooperativas e empresas privadas, como alternativa para aprimorar o processo de transferência de tecnologia, com base no método denominado de "Sistema de Treino e Visita" (T & V), para a transferência e validação de conhecimentos e tecnologias no Rio Grande do Sul. Esse método consiste em atingir número expressivo de técnicos e produtores, através de sucessivos processos de comunicação, conjugados com uma série de atividades de apoio, na busca de aproximação dos agentes do sistema de informação agrícola. Estabeleceram-se parcerias regionais nas regiões Norte, Planalto, Alto Uruguai, Alto Jacuí, Noroeste e Missões, principais pólos de produção de grãos do Rio Grande do Sul, e ocorreram encontros focados na divulgação do método, na construção de uma agenda comum e na valorização de experiências consolidadas no âmbito do grupo. Assim, foram internalizados os elementos centrais do método e constituiu-se um espaço de capacitação, de antecipação de problemas nas principais culturas, de debate e apresentação de trabalhos, não só originários da pesquisa, mas também de informes relevantes das instituições de maneira ágil
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