2,268 research outputs found
Violations of local realism by two entangled quNits
Results obtained in two recent papers, \cite{Kaszlikowski} and \cite{Durt},
seem to indicate that the nonlocal character of the correlations between the
outcomes of measurements performed on entangled systems separated in space is
not robust in the presence of noise. This is surprising, since entanglement
itself is robust. Here we revisit this problem and argue that the class of
gedanken-experiments considered in \cite{Kaszlikowski} and \cite{Durt} is too
restrictive. By considering a more general class, involving sequences of
measurements, we prove that the nonlocal correlations are in fact robust.Comment: Reference added, 3 pages, accepted for publication in J. Phys. A:
Math. and Genera
Scale-Invariance and the Strong Coupling Problem
The effective theory of adiabatic fluctuations around arbitrary
Friedmann-Robertson-Walker backgrounds - both expanding and contracting -
allows for more than one way to obtain scale-invariant two-point correlations.
However, as we show in this paper, it is challenging to produce scale-invariant
fluctuations that are weakly coupled over the range of wavelengths accessible
to cosmological observations. In particular, requiring the background to be a
dynamical attractor, the curvature fluctuations are scale-invariant and weakly
coupled for at least 10 e-folds only if the background is close to de Sitter
space. In this case, the time-translation invariance of the background
guarantees time-independent n-point functions. For non-attractor solutions, any
predictions depend on assumptions about the evolution of the background even
when the perturbations are outside of the horizon. For the simplest such
scenario we identify the regions of the parameter space that avoid both
classical and quantum mechanical strong coupling problems. Finally, we present
extensions of our results to backgrounds in which higher-derivative terms play
a significant role.Comment: 17 pages + appendices, 3 figures; v2: typos fixe
A level playing ‘field’? A Bourdieusian analysis of the career aspirations of further education students on sports courses
There is currently a distinct dearth of research into how sports students’ career aspirations are formed during their post-compulsory education. This article, based on an ethnographic study of sport students in tertiary education, draws on data collected from two first-year cohorts (n = 34) on two different courses at a further education college in England. The study draws on ethnographic observations, and semi-structured group interviews, to examine in-depth the contrasting occupational perspectives emergent within these two groups of mainly working-class students, and how specific cultural practices affect students’ career aspirations. Utilising a Bourdieusian framework, the paper analyses the internalised, often latent cultural practices that impact upon these students’ diverse career aspirations. The hitherto under-researched dimension of inter-habitus interaction and also the application of doxa are outlined. The article reveals how the two student cohorts are situated within a complex field of relations, where struggles for legitimisation, academic accomplishment and numerous forms of lucrative capital become habituated. The study offers salient Bourdieusian-inspired insights into the career aspirations of these predominantly working-class students and the ways in which certain educational practices contribute to the production and reproduction of class inequalities
Mutations in DYNC2LI1 disrupt cilia function and cause short rib polydactyly syndrome.
The short rib polydactyly syndromes (SRPSs) are a heterogeneous group of autosomal recessive, perinatal lethal skeletal disorders characterized primarily by short, horizontal ribs, short limbs and polydactyly. Mutations in several genes affecting intraflagellar transport (IFT) cause SRPS but they do not account for all cases. Here we identify an additional SRPS gene and further unravel the functional basis for IFT. We perform whole-exome sequencing and identify mutations in a new disease-producing gene, cytoplasmic dynein-2 light intermediate chain 1, DYNC2LI1, segregating with disease in three families. Using primary fibroblasts, we show that DYNC2LI1 is essential for dynein-2 complex stability and that mutations in DYNC2LI1 result in variable length, including hyperelongated, cilia, Hedgehog pathway impairment and ciliary IFT accumulations. The findings in this study expand our understanding of SRPS locus heterogeneity and demonstrate the importance of DYNC2LI1 in dynein-2 complex stability, cilium function, Hedgehog regulation and skeletogenesis
Direct Higgs production and jet veto at the Tevatron and the LHC in NNLO QCD
We consider Higgs boson production through gluon--gluon fusion in hadron
collisions, when a veto is applied on the transverse momenta of the
accompanying hard jets. We compute the QCD radiative corrections to this
process at NLO and NNLO. The NLO calculation is complete. The NNLO calculation
uses the recently evaluated NNLO soft and virtual QCD contributions to the
inclusive cross section. We find that the jet veto reduces the impact of the
NLO and NNLO contributions, the reduction being more sizeable at the LHC than
at the Tevatron.Comment: 22 pages, 12 postscript figure
Lack of SARS Transmission among Healthcare Workers, United States
Healthcare workers accounted for a large proportion of persons with severe acute respiratory syndrome (SARS) during the worldwide epidemic of early 2003. We conducted an investigation of healthcare workers exposed to laboratory-confirmed SARS patients in the United States to evaluate infection-control practices and possible SARS-associated coronavirus (SARS-CoV) transmission. We identified 110 healthcare workers with exposure within droplet range (i.e., 3 feet) to six SARS-CoV–positive patients. Forty-five healthcare workers had exposure without any mask use, 72 had exposure without eye protection, and 40 reported direct skin-to-skin contact. Potential droplet- and aerosol-generating procedures were infrequent: 5% of healthcare workers manipulated a patient’s airway, and 4% administered aerosolized medication. Despite numerous unprotected exposures, there was no serologic evidence of healthcare-related SARS-CoV transmission. Lack of transmission in the United States may be related to the relative absence of high-risk procedures or patients, factors that may place healthcare workers at higher risk for infection
Connection Between Optical and VHE Gamma-ray Emission in Blazar Jets
MAGIC has been performing optically triggered Target of Opportunity
observations of flaring blazars since the beginning of its scientific
operations. The alerts of flaring blazars originate from Tuorla Blazar
Monitoring Programme, which started the optical monitoring of candidtate TeV
blazars in 2002 and has now collected up to eight years of data on more than 60
blazars. These ToO observations have resulted in the discovery of five new VHE
gamma-ray emitting blazars (S5 0716+714, 1ES 1011+496, Mrk 180, ON 325 and B3
2247+381). In addition part of the discovery of BL Lac and the discovery of 3C
279 was made during a high optical state. In this contribution we present a
detailed analysis of the optical light curves which are then compared to MAGIC
observations of the same sources. We aim to answer the question: "Is there a
connection between optical and VHE -ray high states in blazars or have we just
been lucky?"Comment: 6 pages, 1 figure, 2 tables, proceedings for the Beamed and Unbeamed
Gamma-Rays from Galaxies workshop, Olos, April 11-15 201
Effects of Policies Designed to Keep Firearms from High-Risk Individuals
This article summarizes and critiques available evidence from studies published between 1999 and August 2014 on the effects of policies designed to keep firearms from high-risk individuals in the United States. Some prohibitions for high-risk individuals (e.g., those under domestic violence restraining orders, violent misdemeanants) and procedures for checking for more types of prohibiting conditions are associated with lower rates of violence. Certain laws intended to prevent prohibited persons from accessing firearms -- rigorous permit-to-purchase, comprehensive background checks, strong regulation and oversight of gun dealers, and requiring gun owners to promptly report lost or stolen firearms -- are negatively associated with the diversion of guns to criminals. Future research is needed to examine whether these laws curtail nonlethal gun violence and whether the effects of expanding prohibiting conditions for firearm possession are modified by the presence of policies to prevent diversion
How can onchocerciasis elimination in Africa be accelerated? Modelling the impact of increased ivermectin treatment frequency and complementary vector control
Background: Great strides have been made toward onchocerciasis elimination by mass drug administration (MDA) of ivermectin. Focusing on MDA-eligible areas, we investigated where the elimination goal can be achieved by 2025 by continuation of current practice (annual MDA with ivermectin) and where intensification or additional vector control is required. We did not consider areas hypoendemic for onchocerciasis with loiasis coendemicity where MDA is contraindicated. Methods: We used 2 previously published mathematical models, ONCHOSIM and EPIONCHO, to simulate future trends in microfilarial prevalence for 80 different settings (defined by precontrol endemicity and past MDA frequency and coverage) under different future treatment scenarios (annual, biannual, or quarterly MDA with different treatment coverage through 2025, with or without vector control strategies), assessing for each strategy whether it eventually leads to elimination. Results: Areas with 40%–50% precontrol microfilarial prevalence and ≥10 years of annual MDA may achieve elimination with a further 7 years of annual MDA, if not achieved already, according to both models. For most areas with 70%–80% precontrol prevalence, ONCHOSIM predicts that either annual or biannual MDA is sufficient to achieve elimination by 2025, whereas EPIONCHO predicts that elimination will not be achieved even with complementary vector control. Conclusions: Whether elimination will be reached by 2025 depends on precontrol endemicity, control history, and strategies chosen from now until 2025. Biannual or quarterly MDA will accelerate progress toward elimination but cannot guarantee it by 2025 in high-endemicity areas. Long-term concomitant MDA and vector control for high-endemicity areas might be useful
Digital technology and governance in transition: The case of the British Library
Comment on the organizational consequences of the new information and communications technologies (ICTs) is pervaded by a powerful imagery of disaggregation and a tendency for ?virtual? forms of production to be seen as synonymous with the ?end? of bureaucracy. This paper questions the underlying assumptions of the ?virtual organization?, highlighting the historically enduring, diversified character of the bureaucratic form. The paper then presents case study findings on the web-based access to information resources now being provided by the British Library (BL). The case study evidence produces two main findings. First, radically decentralised virtual forms of service delivery are heavily dependent on new forms of capacity-building and information aggregation. Second, digital technology is embedded in an inherently contested and contradictory context of institutional change. Current developments in the management and control of digital rights are consistent with the commodification of the public sphere. However, the evidence also suggests that scholarly access to information resources is being significantly influenced by the ?information society? objectives of the BL and other institutional players within the network of UK research libraries
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