92,411 research outputs found
Ethical Allocation of Preexposure HIV Prophylaxis
Civil society-led movements transformed global AIDS action from deep skepticism about extending anti-retroviral (ARV) treatment in low and middle-income countries to an historic scaling up of treatment towards universal access. The AIDS movement, however, is at an inflection point due to the interplay of key health and economic determinants—the global financial downturn, tight foreign aid budgets, and intense resource competition. Policy makers will now have to consider implementation of a new intervention—pre-exposure prophylaxis (PrEP), which could mean a diversion of ARVs from treatment to prevention. The principle underlying PrEP is that ARVs could prevent HIV infection among people who are HIV-negative and at high risk. Unlike existing prevention strategies such as voluntary counseling and testing (VCT), condoms, and male circumcision, PrEP is a continuous biomedical intervention. Although it will take several years to fully establish the clinical efficacy of PrEP in varying populations, the encouraging early results from CAPRISA, iPrEx, and CDC 4323 have accelerated global dialogue on its proof of deliverability. The studies encompass diverse populations, including injecting drug users (IDUs), MSM, serodiscordant heterosexual couples, and sex workers. These studies will be completed at different times, raising the question: if a trial demonstrates effectiveness for a given study group, should PrEP be used for others? The ethical issues raised by PrEP are difficult, but not insurmountable. Examining comparative cost-effectiveness, good governance, overcoming access barriers, and ensuring quality improvement would help ensure ethical allocation under circumstances of scarcity
Off-diagonal magnetoimpedance in field-annealed Co-based amorphous ribbons
The off-diagonal magnetoimpedance in field-annealed CoFeSiB amorphous ribbons
was measured in the low-frequency range using a pick-up coil wound around the
sample. The asymmetric two-peak behavior of the field dependence of the
off-diagonal impedance was observed. The asymmetry is attributed to the
formation of a hard magnetic crystalline phase at the ribbon surface. The
experimental results are interpreted in terms of the surface impedance tensor.
It is assumed that the ribbon consists of an inner amorphous region and surface
crystalline layers. The coupling between the crystalline and amorphous phases
is described through an effective bias field. A qualitative agreement between
the calculated dependences and experimental data is demonstrated. The results
obtained may be useful for development of weak magnetic-field sensors.Comment: 19 pages, 6 figure
Search for Heavy Sterile Neutrinos in Trileptons at the LHC
We present a search strategy for both Dirac and Majorana sterile neutrinos
from the purely leptonic decays of and
at the 14 TeV LHC. The discovery and exclusion
limits for sterile neutrinos are shown using both the Cut-and-Count (CC) and
Multi-Variate Analysis (MVA) methods. We also discriminate between Dirac and
Majorana sterile neutrinos by exploiting a set of kinematic observables which
differ between the Dirac and Majorana cases. We find that the MVA method,
compared to the more common CC method, can greatly enhance the discovery and
discrimination limits. Two benchmark points with sterile neutrino mass GeV and 50 GeV are tested. For an integrated luminosity of 3000 , sterile neutrinos can be found with significance if
heavy-to-light neutrino mixings ,
while Majorana vs. Dirac discrimination can be reached if at least one of the
mixings is of order .Comment: 4 pages, 6 figures. arXiv admin note: substantial text overlap with
arXiv:1703.0193
Signatures of Dirac and Majorana Sterile Neutrinos in Trilepton Events at the LHC
Heavy sterile neutrinos with masses below can induce trilepton events
at the 14 TeV LHC through purely leptonic decays of and where the heavy neutrino will be
in an intermediate state on its mass shell. Discovery and exclusion limits for
the heavy neutrinos are found using both Cut-and-Count (CC) and a Multi-Variate
Analysis (MVA) methods in this study. We also show that it is possible to
discriminate between a Dirac and a Majorana heavy neutrino, even when lepton
number conservation cannot be directly tested due to unobservability of the
final state neutrino. This discrimination is done by exploiting a combined set
of kinematic observables that differ between the Majorana vs. Dirac cases. We
find that the MVA method can greatly enhance the discovering and discrimination
limits in comparison with the CC method. For a 14-TeV collider with
integrated luminosity of 3000 , sterile neutrinos can be found
with 5 significance if heavy-to-light neutrino mixings , while the Majorana vs. Dirac type can be
distinguished if or even
if one of the mixing elements is at least an order
of magnitude smaller than the other.Comment: 10 pages, 12 figure
Inclusive angular distribution of alpha and Li fragments produced in the Fe-C and Fe-Pb collisions at 1.88 GeV/u
The LS (laboratory system) emission angles theta for 2188 and 298 Li fragments, produced inclusively in relativistic Fe-C and Fe-Pb collisions, have been measured in reference to incident Fe-ion beam tracks nearby in nuclear emulsion. An empirical differential frequency formula, dN(cot theta) = exp (a + b cot theta)d(cot theta) is obtained with the constant b approx. = -0.026 at 1.88 GeV/u, which seems to be independent on the kinds of target nucleus as well as on the kinds of projectile fragments
The O’Neill Institute for National and Global Health Law: Discovering Innovative Solutions for the Most Pressing Health Problems Facing the Nation and the World
The connection between health and an individual’s ability to function in society, as well as the importance of health to a society’s economic, political, and social wellbeing necessitates finding innovative solutions to the world’s most pressing health problems. The O’Neill Institute for National and Global Health Law at Georgetown University seeks to demonstrate the role that academia can play in addressing complex national and global health problems in a comprehensive, evidence-based, intellectually-rigorous, and nonpartisan manner. The O’Neill Institute currently has three research programs: global health law, national health law, and the center for disease prevention and outcomes. Projects within these programs examine a broad range of health law and policy issues, such as global health governance, global tobacco control, health worker migration, emergency preparedness, national and Chinese health reform, HIV and AIDS issues, food safety, and personalized medicine. These projects merge the scholarly capacity within the institute with the resources of its partners, which include the World Health Organization, World Bank, the Bill & Melinda Gates Foundation, the U.S. Centers for Disease Control and Prevention, and the Campaign for Tobacco Free Kids. Additionally, the faculty and fellows of the O’Neill Institute regularly produce high-level scholarship and engage in teaching offering multi-disciplinary course offerings and innovative graduate degree programs. URL: http://www.law.georgetown.edu/oneillinstitute/documents/2010-03-09_oneill-solutions.pdf; http://mjlst.umn.edu/uploads/Pf/V1/PfV1QhiCT6lUOsv1AqDTCA/111_gostin.pdf
Child Abuse Reporting: Rethinking Child Protection
The general public has been bewildered by the magnitude of sex abuse cases and the widespread failure by pillars of the community to notify appropriate authorities. The crime of sexually abusing children is punishable in all jurisdictions and this article examines the duty to report suspected cases by individuals in positions of trust over young people, such as in the church or university sports. The Federal Child Abuse Prevention and Treatment Act (CAPTA) defines child maltreatment as an act or failure to act on the part of a parent or caregiver that results in death, serious physical or emotional harm, sexual abuse, or exploitation, and establishes minimum federal standards. Each state has its own definitions of maltreatment and every state identifies persons who are required to report child abuse. As such, state law is highly variable in defining who has a mandatory duty to report, and clergy and other individuals in close supervision of children (e.g., athletic coaches, scout leaders, volunteers in religious programs, and university officials) may necessarily hold such duty.
The article outlines why there are strong moral reasons the law should require all adults in close supervision of children to report any individual who they have good reason to believe has abused a child and moreover outlines how to ensure prompt reporting of abuse, while still ensuring that respected individuals are not falsely accused
Subwavelength localization and toroidal dipole moment of spoof surface plasmon polaritons
We experimentally and theoretically demonstrate subwavelength scale localization of spoof surface plasmon polaritons at a point defect in a two-dimensional groove metal array. An analytical expression for dispersion relation of spoof surface plasmon polaritons substantiates the existence of a band gap where a defect mode can be introduced. A waveguide coupling method allows us to excite localized spoof surface plasmon polariton modes and measure their resonance frequencies. Numerical calculations confirm that localized modes can have a very small modal volume and a high Q factor both of which are essential in enhancing light-matter interactions. Interestingly, we find that the localized spoof surface plasmon polariton has a significant toroidal dipole moment, which is responsible for the high Q factor, as well as an electric quadrupole moment. In addition, the dispersion properties of spoof surface plasmon polaritons are analyzed using a modal expansion method and numerical calculations
Development of an airborne laser bathymeter
An airborne laser depth sounding system was built and taken through a complete series of field tests. Two green laser sources were tried: a pulsed neon laser at 540 nm and a frequency-doubled Nd:YAG transmitter at 532 nm. To obtain a depth resolution of better than 20 cm, the pulses had a duration of 5 to 7 nanoseconds and could be fired up to at rates of 50 pulses per second. In the receiver, the signal was detected by a photomultiplier tube connected to a 28 cm diameter Cassegrainian telescope that was aimed vertically downward. Oscilloscopic traces of the signal reflected from the sea surface and the ocean floor could either be recorded by a movie camera on 35 mm film or digitized into 500 discrete channels of information and stored on magnetic tape, from which depth information could be extracted. An aerial color movie camera recorded the geographic footprint while a boat crew of oceanographers measured depth and other relevant water parameters. About two hundred hours of flight time on the NASA C-54 airplane in the area of Chincoteague, Virginia, the Chesapeake Bay, and in Key West, Florida, have yielded information on the actual operating conditions of such a system and helped to optimize the design. One can predict the maximum depth attainable in a mission by measuring the effective attenuation coefficient in flight. This quantity is four times smaller than the usual narrow beam attenuation coefficient. Several square miles of a varied underwater landscape were also mapped
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