928 research outputs found
First results of the two square meters multilayer glass composite mirror design proposed for the Cherenkov Telescope Array developed at INFN
The Cherenkov Telescope Array (CTA) is a future ground-based gamma-ray
astronomy detector that will consist of more than 100 Imaging Atmospheric
Cherenkov Telescopes of different sizes. The total reflective surface of
roughly 10 000 m requires unprecedented technological efforts towards a
cost-efficient production of light-weight and reliable mirror substrates at
high production rate. We report on a new mirror concept proposed for CTA
developed by INFN, which is based on the replication from a spherical convex
mold under low pressure. The mirror substrate is an open structure design made
by thin glass layers at the mirror's front and rear interspaced by steel
cylinders. A first series of nominal size mirrors has been produced, for which
we discuss the optical properties in terms of radius of curvature and focusing
power
The Atmospheric Monitoring Strategy for the Cherenkov Telescope Array
The Imaging Atmospheric Cherenkov Technique (IACT) is unusual in astronomy as
the atmosphere actually forms an intrinsic part of the detector system, with
telescopes indirectly detecting very high energy particles by the generation
and transport of Cherenkov photons deep within the atmosphere. This means that
accurate measurement, characterisation and monitoring of the atmosphere is at
the very heart of successfully operating an IACT system. The Cherenkov
Telescope Array (CTA) will be the next generation IACT observatory with an
ambitious aim to improve the sensitivity of an order of magnitude over current
facilities, along with corresponding improvements in angular and energy
resolution and extended energy coverage, through an array of Large (23m),
Medium (12m) and Small (4m) sized telescopes spread over an area of order
~km. Whole sky coverage will be achieved by operating at two sites: one in
the northern hemisphere and one in the southern hemisphere. This proceedings
will cover the characterisation of the candidate sites and the atmospheric
calibration strategy. CTA will utilise a suite of instrumentation and analysis
techniques for atmospheric modelling and monitoring regarding pointing
forecasts, intelligent pointing selection for the observatory operations and
for offline data correction.Comment: 6 pages. To appear in the proceedings of the Adapting to the
Atmosphere conference 201
Constraining the Dark Matter decay lifetime with very deep observations of the Perseus cluster with the MAGIC telescopes
We present preliminary results on Dark Matter searches from observations of
the Perseus galaxy cluster with the MAGIC Telescopes. MAGIC is a system of two
Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La
Palma, Spain. Galaxy clusters are the largest known gravitationally bound
structures in the Universe, with masses of ~10^15 Solar masses. There is strong
evidence that galaxy clusters are Dark Matter dominated objects, and therefore
promising targets for Dark Matter searches, particularly for decay signals.
MAGIC has taken almost 300 hours of data on the Perseus Cluster between 2009
and 2015, the deepest observational campaign on any galaxy cluster performed so
far in the very high energy range of the electromagnetic spectrum. We analyze
here a small sample of this data and search for signs of dark matter in the
mass range between 100 GeV and 20 TeV. We apply a likelihood analysis optimized
for the spectral and morphological features expected in the dark matter decay
signals. This is the first time that a dedicated Dark Matter optimization is
applied in a MAGIC analysis, taking into account the inferred Dark Matter
distribution of the source. The results with the full dataset analysis will be
published soon by the MAGIC Collaboration
Land use change effects on soil organic carbon store. An opportunity to soils regeneration in Mediterranean areas: Implications in the 4p1000 notion
Abstract The knowledge about land management effects on soil capacity to store carbon is necessary to planning effective strategies by managers and decision-makers. In this study we analyzed the land use change (LUC) effects on soil organic carbon stocks (SOC-S) for long term in the Sardinia region - Italy (Mediterranean area). Throughout the 20th century, the studied area has undergone different LUC. The first LUC was in 1938, from forest to agricultural land under three different uses: vineyards, hay crop and pasture, later (1966) some of this agricultural land were abandoned to seminatural ecosystem (second LUC). The different LUC affected to SOC-S causing decarbonization, carbonization and recarbonization processes along the soil profile. The different land uses studied chronologically were: i) natural forest - cork oak forest (Cof), ii) tilled vineyard (Tv), iii) no tilled grassed vineyard (Ntgv), iv) hay crop (Hc), v) pasture - silvopastoral and silvoarable practices (P), and vi) former vineyard - vineyards abandoned and naturally revegetated (Fv). The first LUC (Cof to Tv, Ntgv, Hc and P) caused 5.1% and 37.5% reduction on SOC-S for Tv and Ntgv (soil decarbonization), however, the SOC-S increased 47.1% and 51.3% for Hc and P respectively (soil carbonization). The second LUC (Tv and Ntgv to Fv) increased the SOC-S on average 66.3% (soil recarbonization). In general, these effects were observed principally in depth. This study shows the importance of land use and LUC with respect to SOC-S, and that the human action can degrade and/or regenerate the soil, affecting to soil functions. Consequently, is necessity to promote good environmental practices to improve the soil functions and to reduce the greenhouse gases (ecosystem services). On the presumption that the SOC sequestration through of agricultural management can reduced the atmospheric CO2 concentration (4p1000 target in the XXI Conference of the Parties – Paris, 2015). Therefore, the soils regeneration via carbonization and/or recarbonization is an opportunity to prevent the climate change
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
Relationship Between Legal Blindness and Depression
The higher prevalence rates of depression in visually-impaired individuals than the general population indicates that the condition per se increases the risk of depression. A person that is aware of the progressive loss of visual acuteness may have feelings of insecurity, anxiety, loss of independence and changes in social functioning, leading to depression. Several studies assessing the association between depressive symptoms and severity of vision loss have yielded inconsistent results. Some do not show any association, whereas others reported that depression severity is higher in those with substantial vision loss. The general aim of this manuscript was to determine the prevalence of depression in patients diagnosed with legal blindness in the Eye Care Service at the Hospital Córdoba between June 2016 and June 2017. The study sample consisted of 41 patients. The level of depression was assessed using the Zung scale and the degree of dependence in daily life activities was defined using the Barthel index. Data was anonymized for inclusion in a computer database and statistical confidentiality was protected. Data was analyzed using InfoStat statistical software. The results revealed a relation between legal blindness, degrees of dependency and depressive symptoms in patients of the Eye Care Service of the Hospital Córdoba. It is very important for health professionals to be trained to detect early signs and symptoms of depression and have the necessary tools for such an approach. Epub: October 1, 2019
Relationship Between Legal Blindness and Depression
The higher prevalence rates of depression in visually-impaired individuals than the general population indicates that the condition per se increases the risk of depression. A person that is aware of the progressive loss of visual acuteness may have feelings of insecurity, anxiety, loss of independence and changes in social functioning, leading to depression. Several studies assessing the association between depressive symptoms and severity of vision loss have yielded inconsistent results. Some do not show any association, whereas others reported that depression severity is higher in those with substantial vision loss. The general aim of this manuscript was to determine the prevalence of depression in patients diagnosed with legal blindness in the Eye Care Service at the Hospital Córdoba between June 2016 and June 2017. The study sample consisted of 41 patients. The level of depression was assessed using the Zung scale and the degree of dependence in daily life activities was defined using the Barthel index. Data was anonymized for inclusion in a computer database and statistical confidentiality was protected. Data was analyzed using InfoStat statistical software. The results revealed a relation between legal blindness, degrees of dependency and depressive symptoms in patients of the Eye Care Service of the Hospital Córdoba. It is very important for health professionals to be trained to detect early signs and symptoms of depression and have the necessary tools for such an approach. Epub: October 1, 2019
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