981 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 calibration of the first Large-Sized Telescope of the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) represents the next generation of very
high-energy gamma-ray observatory, which will provide broad coverage of gamma
rays from 20 GeV to 300 TeV with unprecedented sensitivity. CTA will employ
three different sizes of telescopes, and the Large-Sized Telescopes (LSTs) of
23-m diameter dish will provide the sensitivity in the lowest energies down to
20 GeV. The first LST prototype has been inaugurated in October 2018 at La
Palma (Canary Islands, Spain) and has entered the commissioning phase. The
camera of the LST consists of 265 PMT modules. Each module is equipped with
seven high-quantum-efficiency Photomultiplier Tubes (PMTs), a slow control
board, and a readout board. Ensuring high uniformity and precise
characterization of the camera is the key aspects leading to the best
performance and low systematic uncertainty of the LST cameras. Therefore, prior
to the installation on site, we performed a quality check of all PMT modules.
Moreover, the absolute calibration of light throughput is essential to
reconstruct the amount of light received by the telescope. The amount of light
is affected by the atmosphere, by the telescope optical system and camera, and
can be calibrated using the ring-shaped images produced by cosmic-ray muons. In
this contribution, we will show the results of off-site quality control of PMT
modules and on-site calibration using muon rings. We will also highlight the
status of the development of Silicon Photomultiplier modules that could be
considered as a replacement of PMT modules for further improvement of the
camera
Conservation agriculture with drip irrigation: Effects on soil quality and crop yield in sub-Saharan Africa
The traditional agriculture production system in sub-Saharan Africa (SSA) caused significant soil erosion and degradation of soil quality. In addition, dependability of rainfall for irrigation needs limits the crop production. Advanced agricultural practices are thus needed at the local level to sustain the livelihood of smallholder farmers in the region. In this study, conservation agriculture (CA) practice with drip irrigation technology was compared (using field experiments and watershed modeling) with the traditional conventional tillage (CT) practice for its potential in improving soil quality and crop productivity in the region. Biophysical data were collected (2015 to 2017) from a total of 43 paired plots (CA and CT) at four study sites in SSA: Dangishita and Robit in Ethiopia, Yemu in Ghana, and Mkindo in Tanzania. The Agricultural Policy/Environmental eXtender (APEX) model was calibrated and validated with reasonable efficiency in simulating crop yields for both CA and CT practices; average PBIAS ≤±12% and ≤±11%, for CA and CT. The impact of the CA system on soil quality (soil carbon [C] and nitrogen [N]) was analyzed based on the well-tested model prediction results. The total C and N were increased under CA across the study sites on average by 6% and 4.1%, when compared to CT over the study period. Both the experiment and model prediction showed that crop yield was significantly improved by CA—on average 37.4% increases across the sites when compared to CT. Conservation agriculture with drip irrigation was an efficient local strategy to improve crop production in the region while enhancing the ecosyste
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
Phytotherapy as an alternative for the treatment of human papilloma virus infections in Nigeria: a review
Human papillomavirus (HPV) has been incriminated as the causal agent of cervical cancer which has been rated as the second most common cancers among women in developing countries and seventh most common cancers in the developed world. In spite of the fact that HPV has been the major cause of cervical cancer, the dilemma lies in finding a cost-effective therapy. Approximately 291 million women are infected with HPV worldwide, 32% of whom are infected with HPV16 or HPV18. The estimated prevalence of HPV in sub-Saharan Africa is 24% and 11.7% globally. There have been studies reporting specific HPV prevalence rates in some part of Nigeria, with 37% in Abuja, 10% in Port Harcourt, and 26.3% in Ibadan. In the Nigeria population, awareness of HPV infections is low, HPV vaccines are inadequate, and the cost of HPV vaccination per person is beyond what an average citizen can afford. It has been suggested that herbal therapy such as Echinacea therapy reduces HPV replication and enhances the immune system. Although there is yet no scientific proof of the efficacy of Echinacea therapy against HPV infections, future emphasis should be placed on scientific research into this alternative therapy. There is need for more studies on development of antiviral agents against HPV, with a prospect of easy accessibility and affordability in Nigeria.Keywords: Phytotherapy; HPV; Cervical cancer; Nigeri
The impact of integrating food supplementation, nutritional education and HAART (Highly Active Antiretroviral Therapy) on the nutritional status of patients living with HIV/AIDS in Mozambique: result from the DREAM programme
DREAM (Drug Resources Enhancement against AIDS and Malnutrition) is
a multiregional health program active in Mozambique since 2002 and provides free of charge an integrating package of care consisting of peer to peer nutritional and health education,
food supplementation, voluntary counseling and testing, immunological, virological, clinical
assessment and HAART (Highly Active AntiRetroviral Treatment). The main goals of this
paper are to describe the state of health and nutrition and the adequacy of the diet of a
sample of HIV/AIDS patients in Mozambique on HAART and not.
A single-arm retrospective cohort study was conducted. 106 HIV/AIDS adult patients (84 in
HAART), all receiving food supplementation and peer-to-peer nutritional education, were
randomly recruited in Mozambique in two public health centres where DREAM is running.
The programme is characterized by: provision of HAART, clinical and laboratory monitoring,
peer to peer health and nutritional education and food supplementation. We measured
BMI, haemoglobin, viral load, CD4 count at baseline (T0) and after at least 1 year (T1).
Dietary intake was estimated using 24h food recall and dietary diversity was assessed by
using the Dietary Diversity Score (DDS) at T1.
Overall, the patients'diet appeared to be quite balanced in nutrients. In the cohort not in
HAART the mean BMI values showed an increases but not significant (initial value: 21.9±2.9;
final value: 22.5±3.3 ) and the mean haemoglobin values (g/dl) showed a significant increases
(initial value: 10.5+ 2.1; final value: 11.5±1.7 p< 0.024) . In the cohort in HAART, both the
mean of BMI value (initial value: 20.7±3.9; final value: 21.9±3.3 p< 0.001) and of haemoglobin
(initial value: 9.9±2.2; final value: 10.8±1.7 p< 0.001) showed a higher significant increase.
The increase in BMI was statistically associated with the DDS in HAART patients.
In conclusion nutritional status improvement was observed in both cohorts. The improvement
in BMI was significant and substantially higher in HAART patients because of the impact
of HAART on nutritional status of AIDS patients. Subjects on HAART and with a DDS >
5, showed a substantial BMI gain. This association showed an additional expression of the
synergic effect of integrating food supplementation, nutritional education and HAART on
the nutritional status of African AIDS patients and also highlights the complementary role
of an adequate and diversified diet in persons living with HIV/AIDS in resources limited
settings
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
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
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