1,341 research outputs found
HIV Antibody Screening: An Ethical Framework for Evaluating Proposed Programs
The acquired immunodeficiency syndrome (AIDS) poses a compelling ethical challenge to medicine, science, public health, the legal system, and our political democracy. This report focuses on one aspect of that challenge: the use of blood tests to identify individuals who have been infected with the retrovirus human immunodeficiency virus (HIV). In this article, we follow the terminology recently proposed by the International Committee on the Taxonomy of Viruses; that is, we use the term human immunodeficiency virus. This replaces the more cumbersome dual terminology of human T-cell lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV).
The issue is urgent: the tests are already in use and plans to implement them much more broadly are being proposed. The issue is also complex: at stake is a potential conflict between the community\u27s interests in stopping the spread of a devastating disease and in preserving important values of individual liberty and equal rights
Exponential separation between quantum communication and logarithm of approximate rank
Chattopadhyay, Mande and Sherif (ECCC 2018) recently exhibited a total Boolean function, the sink function, that has polynomial approximate rank and polynomial randomized communication complexity. This gives an exponential separation between randomized communication complexity and logarithm of the approximate rank, refuting the log-approximate-rank conjecture. We show that even the quantum communication complexity of the sink function is polynomial, thus also refuting the quantum log-approximate-rank conjecture. Our lower bound is based on the fooling distribution method introduced by Rao and Sinha (ECCC 2015) for the classical case and extended by Anshu, Touchette, Yao and Yu (STOC 2017) for the quantum case. We also give a new proof of the classical lower bound using the fooling distribution method.</p
Magnetic component
A magnetic component has a core (100) with a cavity (105) and a winding structure (21) accommodated in the cavity (105). The winding structure (21) has a height (27) in a direction transverse to its bottom (126) and top faces (125), and is provided with a number of turns (121) which extend from the bottom (126) to the top face (125). The core (100) has a magnetic gap area (24), which has an extension that is at least 50 % of the height (27) of the winding structure. Therewith, eddy currents are substantially limited
Pre-cycle selection for the superconducting main magnets of the Large Hadron Collider
Pre-cycles for setting up the main magnets of the Large Hadron Collider are necessary for ensuring field reproducibility and low field-decay rates at injection. In this paper we propose standard pre-cycles for the main magnets of the LHC. We study the influence of the pre-cycle parameters on the field decay at injection by two different models. One already proven model is semi-empirical based on magnetic measurements of the magnets. The other is a new network based model of a Rutherford cable which directly calculates the current redistribution and associated magnetization change in the cable strands. The pre-cycle to be used may depend on the history of the machine or may have to be changed because of unforeseen phenomena in the machine. The choice of a new pre-cycle on the basis of magnetic measurements alone is a lengthy process. We confirm the usefulness of the network based model as a tool for selecting new pre-cycles, including decay-blocking degaussing pre-cycles, and compare with magnetic measurements.peer-reviewe
Pre-cycle selection for the superconducting main magnets of the Large Hadron Collider
Pre-cycles for setting up the main magnets of the Large Hadron Collider are necessary for ensuring field reproducibility and low field-decay rates at injection. In this paper we propose standard pre-cycles for the main magnets of the LHC. We study the influence of the pre-cycle parameters on the field decay at injection by two different models. One already proven model is semi-empirical based on magnetic measurements of the magnets. The other is a new network based model of a Rutherford cable which directly calculates the current redistribution and associated magnetization change in the cable strands. The pre-cycle to be used may depend on the history of the machine or may have to be changed because of unforeseen phenomena in the machine. The choice of a new pre-cycle on the basis of magnetic measurements alone is a lengthy process. We confirm the usefulness of the network based model as a tool for selecting new pre-cycles, including decay-blocking degaussing pre-cycles, and compare with magnetic measurements.peer-reviewe
Quantum Coupon Collector
We study how efficiently a k-element set S?[n] can be learned from a uniform superposition |S> of its elements. One can think of |S>=?_{i?S}|i>/?|S| as the quantum version of a uniformly random sample over S, as in the classical analysis of the "coupon collector problem." We show that if k is close to n, then we can learn S using asymptotically fewer quantum samples than random samples. In particular, if there are n-k=O(1) missing elements then O(k) copies of |S> suffice, in contrast to the ?(k log k) random samples needed by a classical coupon collector. On the other hand, if n-k=?(k), then ?(k log k) quantum samples are necessary.
More generally, we give tight bounds on the number of quantum samples needed for every k and n, and we give efficient quantum learning algorithms. We also give tight bounds in the model where we can additionally reflect through |S>. Finally, we relate coupon collection to a known example separating proper and improper PAC learning that turns out to show no separation in the quantum case
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Hepatoportal Venous Trauma: Analysis of Incidence, Morbidity, and Mortality.
ObjectivesAlthough traumatic injuries to the superior mesenteric vein (SMV), portal vein (PV), and hepatic vein (HV) are rare, their impact is significant. Small single center reports estimate mortality rates ranging from 29% to 100%. Our aim is to elucidate the incidence and outcomes associated with each injury due to unique anatomic positioning and varied tolerance of ligation. We hypothesize that SMV injury is associated with a lower risk of mortality compared to HV and PV injury in adult trauma patients.MethodsThe Trauma Quality Improvement Program database (2010-2016) was queried for patients with injury to either the SMV, PV, or HV. A multivariable logistic regression model was used for analysis.ResultsFrom 1,403,466 patients, 966 (0.07%) had a single major hepatoportal venous injury with 460 (47.6%) involving the SMV, 281 (29.1%) involving the PV, and 225 (23.3%) involving the HV. There was no difference in the percentage of patients undergoing repair or ligation between SMV, PV, and HV injuries (P > .05). Compared to those with PV and HV injuries, patients with SMV injury had a higher rate of concurrent bowel resection (38.5% vs 12.1% vs 7.6%, P < .001) and lower mortality (33.3% vs 45.9% vs 49.3%, P < .01). After controlling for covariates, traumatic SMV injury increased the risk of mortality (odds ratio [OR] 1.59, confidence interval [CI] = 1.00-2.54, P = .05) in adult trauma patients; however, this was less than PV injury (OR = 2.77, CI = 1.56-4.93, P = .001) and HV injury (OR = 2.70, CI = 1.46-4.99, P = .002).ConclusionTraumatic SMV injury had a lower rate of mortality compared to injuries of the HV and PV. SMV injury increased the risk of mortality by 60% in adult trauma patients, whereas PV and HV injuries nearly tripled the risk of mortality
Dependence of the static and dynamic field quality of the LHC superconducting dipole magnets on the pre-cycle ramp rate
The allowed multipoles in the Large Hadron Collider (LHC) superconducting dipole magnets decay whilst on a constant current plateau. It is known that the decay amplitude is largely affected by the powering history of the magnet, and particularly by the pre-cycle flat top current and duration and the pre-injection preparation duration. Recently, it was observed that the decay amplitude is also highly dependent on the pre-cycle ramp rate, which has an indirect effect also on the sample of data taken at constant field along the magnet loadlines. This is an important consideration to be included in the Field Description for the LHC (FiDeL), to cope with the difference between the test procedure followed for series tests and the expected cycles during the machine operation. This paper presents the results of the measurements performed to investigate this phenomenon and describes the method included in FiDeL to represent this dependence.peer-reviewe
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