141 research outputs found
Demonstration experiments for solid state physics using a table top mechanical Stirling refrigerator
Liquid free cryogenic devices are acquiring importance in basic science and
engineering. But they can also lead to improvements in teaching low temperature
an solid state physics to graduate students and specialists. Most of the
devices are relatively expensive, but small sized equipment is slowly becoming
available. Here, we have designed several simple experiments which can be
performed using a small Stirling refrigerator. We discuss the measurement of
the critical current and temperature of a bulk YBa2Cu3O(7-d) (YBCO) sample, the
observation of the levitation of a magnet over a YBCO disk when cooled below
the critical temperature and the observation of a phase transition using ac
calorimetry. The equipment can be easily handled by students, and also used to
teach the principles of liquid free cooling
Phallus glutinolens
Phallus glutinolens is a species endemic to Brazil, occurring in fragments of Atlantic Forest in southern and southeastern regions. Up to now, there are only a few records of the species from six different sites. The total population is estimated at around 4,800 mature individuals, in one subpopulation. Based on the habitat decline within the area, we suspect a population decline around 10% in the last three generations (20 years). Phallus glutinolens is, therefore, assessed as Vulnerable C2a(ii).Fil: Trierveiler Pereira, Larissa. Universidade de Sao Paulo; BrasilFil: Vieira de Miranda, M.. Universidade de Sao Paulo; BrasilFil: HernĂĄndez Caffot, MarĂa Luciana. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Baltazar, J. M.. Universidade Federal do SĂŁo Carlos; BrasilFil: Martins da Cuña, K.. Universidade Federal do Rio Grande do Sul; BrasilFil: Alves Silva, G.. Universidade de Sao Paulo; BrasilFil: Kossmann, T.. Universidade Federal de Santa Catarina; BrasilFil: Palacio, M.. Universidade Federal do Rio Grande do Sul; BrasilFil: Drechsler Santos, E. R.. Universidade Federal de Santa Catarina; Brasi
Stability of Terrestrial Planets in the Habitable Zone of Gl 777 A, HD 72659, Gl 614, 47 Uma and HD 4208
We have undertaken a thorough dynamical investigation of five extrasolar
planetary systems using extensive numerical experiments. The systems Gl 777 A,
HD 72659, Gl 614, 47 Uma and HD 4208 were examined concerning the question of
whether they could host terrestrial like planets in their habitable zones
(=HZ). First we investigated the mean motion resonances between fictitious
terrestrial planets and the existing gas giants in these five extrasolar
systems. Then a fine grid of initial conditions for a potential terrestrial
planet within the HZ was chosen for each system, from which the stability of
orbits was then assessed by direct integrations over a time interval of 1
million years. The computations were carried out using a Lie-series integration
method with an adaptive step size control. This integration method achieves
machine precision accuracy in a highly efficient and robust way, requiring no
special adjustments when the orbits have large eccentricities. The stability of
orbits was examined with a determination of the Renyi entropy, estimated from
recurrence plots, and with a more straight forward method based on the maximum
eccentricity achieved by the planet over the 1 million year integration.
Additionally, the eccentricity is an indication of the habitability of a
terrestrial planet in the HZ; any value of e>0.2 produces a significant
temperature difference on a planet's surface between apoapse and periapse. The
results for possible stable orbits for terrestrial planets in habitable zones
for the five systems are summarized as follows: for Gl 777 A nearly the entire
HZ is stable, for 47 Uma, HD 72659 and HD 4208 terrestrial planets can survive
for a sufficiently long time, while for Gl 614 our results exclude terrestrial
planets moving in stable orbits within the HZ.Comment: 14 pages, 18 figures submitted to A&
Strategies to reengage patients lost to follow up in HIV care in high income countries, a scoping review
Background: Despite remarkable achievements in antiretroviral therapy (ART), losses to follow-up (LTFU) might prevent the long-term success of HIV treatment and might delay the achievement of the 90-90-90 objectives. This scoping review is aimed at the description and analysis of the strategies used in high-income countries to reengage LTFU in HIV care, their implementation and impact. Methods: A scoping review was done following Arksey & O'Malley's methodological framework and recommendations from Joanna Briggs Institute. Peer reviewed articles were searched for in Pubmed, Scopus and Web of Science; and grey literature was searched for in Google and other sources of information. Documents were charted according to the information presented on LTFU, the reengagement procedures used in HIV units in high-income countries, published during the last 15 years. In addition, bibliographies of chosen articles were reviewed for additional articles. Results: Twenty-eight documents were finally included, over 80% of them published in the United States later than 2015. Database searches, phone calls and/or mail contacts were the most common strategies used to locate and track LTFU, while motivational interviews and strengths-based techniques were used most often during reengagement visits. Outcomes like tracing activities efficacy, rates of reengagement and viral load reduction were reported as outcome measures. Conclusions: This review shows a recent and growing trend in developing and implementing patient reengagement strategies in HIV care. However, most of these strategies have been implemented in the United States and little information is available for other high-income countries. The procedures used to trace and contact LTFU are similar across reviewed studies, but their impact and sustainability are widely different depending on the country studied
Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study
A41 Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study
In: Addiction Science & Clinical Practice 2017, 12(Suppl 1): A4
Low exposure long-baseline neutrino oscillation sensitivity of the DUNE experiment
The Deep Underground Neutrino Experiment (DUNE) will produce world-leading
neutrino oscillation measurements over the lifetime of the experiment. In this
work, we explore DUNE's sensitivity to observe charge-parity violation (CPV) in
the neutrino sector, and to resolve the mass ordering, for exposures of up to
100 kiloton-megawatt-years (kt-MW-yr). The analysis includes detailed
uncertainties on the flux prediction, the neutrino interaction model, and
detector effects. We demonstrate that DUNE will be able to unambiguously
resolve the neutrino mass ordering at a 3 (5) level, with a 66
(100) kt-MW-yr far detector exposure, and has the ability to make strong
statements at significantly shorter exposures depending on the true value of
other oscillation parameters. We also show that DUNE has the potential to make
a robust measurement of CPV at a 3 level with a 100 kt-MW-yr exposure
for the maximally CP-violating values \delta_{\rm CP}} = \pm\pi/2.
Additionally, the dependence of DUNE's sensitivity on the exposure taken in
neutrino-enhanced and antineutrino-enhanced running is discussed. An equal
fraction of exposure taken in each beam mode is found to be close to optimal
when considered over the entire space of interest
Identification and reconstruction of low-energy electrons in the ProtoDUNE-SP detector
Measurements of electrons from interactions are crucial for the Deep
Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as
searches for physics beyond the standard model, supernova neutrino detection,
and solar neutrino measurements. This article describes the selection and
reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector.
ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and
operated at CERN as a charged particle test beam experiment. A sample of
low-energy electrons produced by the decay of cosmic muons is selected with a
purity of 95%. This sample is used to calibrate the low-energy electron energy
scale with two techniques. An electron energy calibration based on a cosmic ray
muon sample uses calibration constants derived from measured and simulated
cosmic ray muon events. Another calibration technique makes use of the
theoretically well-understood Michel electron energy spectrum to convert
reconstructed charge to electron energy. In addition, the effects of detector
response to low-energy electron energy scale and its resolution including
readout electronics threshold effects are quantified. Finally, the relation
between the theoretical and reconstructed low-energy electron energy spectrum
is derived and the energy resolution is characterized. The low-energy electron
selection presented here accounts for about 75% of the total electron deposited
energy. After the addition of lost energy using a Monte Carlo simulation, the
energy resolution improves from about 40% to 25% at 50~MeV. These results are
used to validate the expected capabilities of the DUNE far detector to
reconstruct low-energy electrons.Comment: 19 pages, 10 figure
A Gaseous Argon-Based Near Detector to Enhance the Physics Capabilities of DUNE
This document presents the concept and physics case for a magnetized gaseous argon-based detector system (ND-GAr) for the Deep Underground Neutrino Experiment (DUNE) Near Detector. This detector system is required in order for DUNE to reach its full physics potential in the measurement of CP violation and in delivering precision measurements of oscillation parameters. In addition to its critical role in the long-baseline oscillation program, ND-GAr will extend the overall physics program of DUNE. The LBNF high-intensity proton beam will provide a large flux of neutrinos that is sampled by ND-GAr, enabling DUNE to discover new particles and search for new interactions and symmetries beyond those predicted in the Standard Model
Snowmass Neutrino Frontier: DUNE Physics Summary
The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino oscillation experiment with a primary physics goal of observing neutrino and antineutrino oscillation patterns to precisely measure the parameters governing long-baseline neutrino oscillation in a single experiment, and to test the three-flavor paradigm. DUNE's design has been developed by a large, international collaboration of scientists and engineers to have unique capability to measure neutrino oscillation as a function of energy in a broadband beam, to resolve degeneracy among oscillation parameters, and to control systematic uncertainty using the exquisite imaging capability of massive LArTPC far detector modules and an argon-based near detector. DUNE's neutrino oscillation measurements will unambiguously resolve the neutrino mass ordering and provide the sensitivity to discover CP violation in neutrinos for a wide range of possible values of ÎŽCP. DUNE is also uniquely sensitive to electron neutrinos from a galactic supernova burst, and to a broad range of physics beyond the Standard Model (BSM), including nucleon decays. DUNE is anticipated to begin collecting physics data with Phase I, an initial experiment configuration consisting of two far detector modules and a minimal suite of near detector components, with a 1.2 MW proton beam. To realize its extensive, world-leading physics potential requires the full scope of DUNE be completed in Phase II. The three Phase II upgrades are all necessary to achieve DUNE's physics goals: (1) addition of far detector modules three and four for a total FD fiducial mass of at least 40 kt, (2) upgrade of the proton beam power from 1.2 MW to 2.4 MW, and (3) replacement of the near detector's temporary muon spectrometer with a magnetized, high-pressure gaseous argon TPC and calorimeter
Snowmass Neutrino Frontier: DUNE Physics Summary
The Deep Underground Neutrino Experiment (DUNE) is a next-generation
long-baseline neutrino oscillation experiment with a primary physics goal of
observing neutrino and antineutrino oscillation patterns to precisely measure
the parameters governing long-baseline neutrino oscillation in a single
experiment, and to test the three-flavor paradigm. DUNE's design has been
developed by a large, international collaboration of scientists and engineers
to have unique capability to measure neutrino oscillation as a function of
energy in a broadband beam, to resolve degeneracy among oscillation parameters,
and to control systematic uncertainty using the exquisite imaging capability of
massive LArTPC far detector modules and an argon-based near detector. DUNE's
neutrino oscillation measurements will unambiguously resolve the neutrino mass
ordering and provide the sensitivity to discover CP violation in neutrinos for
a wide range of possible values of . DUNE is also uniquely
sensitive to electron neutrinos from a galactic supernova burst, and to a broad
range of physics beyond the Standard Model (BSM), including nucleon decays.
DUNE is anticipated to begin collecting physics data with Phase I, an initial
experiment configuration consisting of two far detector modules and a minimal
suite of near detector components, with a 1.2 MW proton beam. To realize its
extensive, world-leading physics potential requires the full scope of DUNE be
completed in Phase II. The three Phase II upgrades are all necessary to achieve
DUNE's physics goals: (1) addition of far detector modules three and four for a
total FD fiducial mass of at least 40 kt, (2) upgrade of the proton beam power
from 1.2 MW to 2.4 MW, and (3) replacement of the near detector's temporary
muon spectrometer with a magnetized, high-pressure gaseous argon TPC and
calorimeter.Comment: Contribution to Snowmass 202
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