968 research outputs found
Search for tau neutrinos at PeV energies and beyond with the MAGIC telescopes
The MAGIC telescopes, located at the Roque de los Muchachos Observatory (2200
a.s.l.) in the Canary Island of La Palma, are placed on the top of a mountain,
from where a window of visibility of about 5 deg in zenith and 80 deg in
azimuth is open in the direction of the surrounding ocean. This permits to
search for a signature of particle showers induced by earth-skimming cosmic tau
neutrinos in the PeV to EeV energy range arising from the ocean. We have
studied the response of MAGIC to such events, employing Monte Carlo simulations
of upward-going tau neutrino showers. The analysis of the shower images shows
that air showers induced by tau neutrinos can be discriminated from the
hadronic background coming from a similar direction. We have calculated the
point source acceptance and the expected event rates, for a sample of generic
neutrino fluxes from photo-hadronic interactions in AGNs. The analysis of about
30 hours of data taken toward the sea leads to a point source sensitivity for
tau neutrinos at the level of the down-going point source analysis of the
Pierre Auger Observatory, if the AUGER observation time is dedicated to a
similar amount by MAGIC.Comment: Proceedings of EPS-HEP 2017, European Physical Society conference on
High Energy Physics, 5-12 July 2017, Venice, Italy. arXiv admin note:
substantial text overlap with arXiv:1708.0614
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
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
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
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
- …