1,050 research outputs found
Sum Uncertainty Relation in Quantum Theory
We prove a new sum uncertainty relation in quantum theory which states that
the uncertainty in the sum of two or more observables is always less than or
equal to the sum of the uncertainties in corresponding observables. This shows
that the quantum mechanical uncertainty in any observable is a convex function.
We prove that if we have a finite number of identically prepared quantum
systems, then a joint measurement of any observable gives an error
less than that of the individual measurements. This has application in quantum
metrology that aims to give better precision in the parameter estimation.
Furthermore, this proves that a quantum system evolves slowly under the action
of a sum Hamiltonian than the sum of individuals, even if they are
non-commuting.Comment: LaTeX file, no figure, 4 page
A Zebrafish Compound Screen Reveals Modulation of Neutrophil Reverse Migration as an Anti-Inflammatory Mechanism
Diseases of failed inflammation resolution are common and largely incurable. Therapeutic induction of inflammation resolution is an attractive strategy to bring about healing without increasing susceptibility to infection. However, therapeutic targeting of inflammation resolution has been hampered by a lack of understanding of the underlying molecular controls. To address this drug development challenge, we developed an in vivo screen for proresolution therapeutics in a transgenic zebrafish model. Inflammation induced by sterile tissue injury was assessed for accelerated resolution in the presence of a library of known compounds. Of the molecules with proresolution activity, tanshinone IIA, derived from a Chinese medicinal herb, potently induced inflammation resolution in vivo both by induction of neutrophil apoptosis and by promoting reverse migration of neutrophils. Tanshinone IIA blocked proinflammatory signals in vivo, and its effects are conserved in human neutrophils, supporting a potential role in treating human inflammation and providing compelling evidence of the translational potential of this screening strategy
Machine Learning in Automated Text Categorization
The automated categorization (or classification) of texts into predefined
categories has witnessed a booming interest in the last ten years, due to the
increased availability of documents in digital form and the ensuing need to
organize them. In the research community the dominant approach to this problem
is based on machine learning techniques: a general inductive process
automatically builds a classifier by learning, from a set of preclassified
documents, the characteristics of the categories. The advantages of this
approach over the knowledge engineering approach (consisting in the manual
definition of a classifier by domain experts) are a very good effectiveness,
considerable savings in terms of expert manpower, and straightforward
portability to different domains. This survey discusses the main approaches to
text categorization that fall within the machine learning paradigm. We will
discuss in detail issues pertaining to three different problems, namely
document representation, classifier construction, and classifier evaluation.Comment: Accepted for publication on ACM Computing Survey
Kepler-22b: A 2.4 Earth-radius Planet in the Habitable Zone of a Sun-like Star
A search of the time-series photometry from NASA's Kepler spacecraft reveals
a transiting planet candidate orbiting the 11th magnitude G5 dwarf KIC 10593626
with a period of 290 days. The characteristics of the host star are well
constrained by high-resolution spectroscopy combined with an asteroseismic
analysis of the Kepler photometry, leading to an estimated mass and radius of
0.970 +/- 0.060 MSun and 0.979 +/- 0.020 RSun. The depth of 492 +/- 10ppm for
the three observed transits yields a radius of 2.38 +/- 0.13 REarth for the
planet. The system passes a battery of tests for false positives, including
reconnaissance spectroscopy, high-resolution imaging, and centroid motion. A
full BLENDER analysis provides further validation of the planet interpretation
by showing that contamination of the target by an eclipsing system would rarely
mimic the observed shape of the transits. The final validation of the planet is
provided by 16 radial velocities obtained with HIRES on Keck 1 over a one year
span. Although the velocities do not lead to a reliable orbit and mass
determination, they are able to constrain the mass to a 3{\sigma} upper limit
of 124 MEarth, safely in the regime of planetary masses, thus earning the
designation Kepler-22b. The radiative equilibrium temperature is 262K for a
planet in Kepler-22b's orbit. Although there is no evidence that Kepler-22b is
a rocky planet, it is the first confirmed planet with a measured radius to
orbit in the Habitable Zone of any star other than the Sun.Comment: Accepted to Ap
Effect of Magnetic-Field on the Microstructure and Macrosegregation in Directionally Solidified Pb-Sn Alloys
An investigation into the influence of a transverse magnetic field (0.45 T) on the mushy zone morphology and macrosegregation in directionally solidified hypoeutectic Pb-Sn alloy shows that the field has no influence on the morphology of dendritic arrays. The field does, however, cause severe distortion in the cellular array morphology. Cellular arrayed growth with the magnetic field results in an extensive channel formation in the mushy zone, as opposed to the well-aligned and uniformly distributed cells formed in the absence of the field. The channels are produced due to the anisotropy in the thermosolutal convection caused by the magnetic field. Macrosegregation, however, along the length of the directionally solidified samples is not influenced by this magnetic field for either the cellular or dendritic arrays
Kidney transplant recipient perspectives on telehealth during the COVID-19 pandemic
The COVID-19 pandemic has challenged the delivery of health services. Telehealth allows delivery of care without in-person contacts and minimizes the risk of vial transmission. We aimed to describe the perspectives of kidney transplant recipients on the benefits, challenges, and risks of telehealth. We conducted five online focus groups with 34 kidney transplant recipients who had experienced a telehealth appointment. Transcripts were thematically analyzed. We identified five themes: minimizing burden (convenient and easy, efficiency of appointments, reducing exposure to risk, limiting work disruptions, and alleviating financial burden); attuning to individual context (depending on stability of health, respect patient choice of care, and ensuring a conducive environment); protecting personal connection and trust (requires established rapport with clinicians, hampering honest conversations, diminished attentiveness without incidental interactions, reassurance of follow-up, and missed opportunity to share lived experience); empowerment and readiness (increased responsibility for self-management, confidence in physical assessment, mental preparedness, and forced independence); navigating technical challenges (interrupted communication, new and daunting technologies, and cognizant of patient digital literacy). Telehealth is convenient and minimizes time, financial, and overall treatment burden. Telehealth should ideally be available after the pandemic, be provided by a trusted nephrologist and supported with resources to help patients prepare for appointments.Brooke M Huuskes, Nicole Scholes-Robertson, Chandana Guha, Amanda Baumgart, Germaine Wong, John Kanellis ... et al
'It is fun, fitness and football really': a process evaluation of a football-based health intervention for men
Concerns about gender inequalities in longevity, particularly premature male mortality, have prompted a range of innovative approaches to health promotion work dating back to the 1980s. In developing such work, sport, and football in particular, has emerged as a gendered cultural field that has utility for engaging men in community health initiatives. Evaluations of such work have shown that health initiatives using football settings, football interventions or even club branding can have positive impact on various health measures in the short and longer term. However, little work to date has looked at the underlying mechanisms that generate success in such projects. This paper presents secondary analysis of data collected during the evaluation of the Premier League Health (PLH) programme specifically focusing on these underlying mechanisms and how/where gender (masculinities) appears in these processes. We draw on interview data with 16 staff who had been involved in the delivery of the PLH initiative and 58 men who took part. Thematic analysis highlighted two overarching (and underpinning) themes: 'Trust', what processes it was key to and how it was developed and sustained; and 'Change', including what it was facilitated by and what impact it had. The paper adds to our understanding of how active listening, flexibility and sustained engagement are key to community-based sports projects' success. Furthermore, it demonstrates how the physicality and sociability of involvement, rather than any direct focus on 'health', are important in acting as a springboard for facilitating reflection and aiding lifestyle changes for men. © 2013 Taylor & Francis
Fast Neutron Detection with 6Li-loaded Liquid Scintillator
We report on the development of a fast neutron detector using a liquid
scintillator doped with enriched Li-6. The lithium was introduced in the form
of an aqueous LiCl micro-emulsion with a di-isopropylnaphthalene-based liquid
scintillator. A Li-6 concentration of 0.15 % by weight was obtained. A 125 mL
glass cell was filled with the scintillator and irradiated with fission-source
neutrons. Fast neutrons may produce recoil protons in the scintillator, and
those neutrons that thermalize within the detector volume can be captured on
the Li-6. The energy of the neutron may be determined by the light output from
recoiling protons, and the capture of the delayed thermal neutron reduces
background events. In this paper, we discuss the development of this 6Li-loaded
liquid scintillator, demonstrate the operation of it in a detector, and compare
its efficiency and capture lifetime with Monte Carlo simulations. Data from a
boron-loaded plastic scintillator were acquired for comparison. We also present
a pulse-shape discrimination method for differentiating between electronic and
nuclear recoil events based on the Matusita distance between a normalized
observed waveform and nuclear and electronic recoil template waveforms. The
details of the measurements are discussed along with specifics of the data
analysis and its comparison with the Monte Carlo simulation
First Measurement of Z/gamma* Production in Compton Scattering of Quasi-real Photons
We report the first observation of Z/gamma* production in Compton scattering
of quasi-real photons. This is a subprocess of the reaction e+e- to
e+e-Z/gamma*, where one of the final state electrons is undetected.
Approximately 55 pb-1 of data collected in the year 1997 at an e+e-
centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been
analysed. The Z/gamma* from Compton scattering has been detected in the
hadronic decay channel. Within well defined kinematic bounds, we measure the
product of cross-section and Z/gamma* branching ratio to hadrons to be
(0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV,
dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60
GeV, dominated by (e)egamma* production, this product is found to be
(4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo
event generators, grc4f and PYTHIA.Comment: 18 pages, LaTeX, 5 eps figures included, submitted to Physics Letters
Search for Higgs Bosons in e+e- Collisions at 183 GeV
The data collected by the OPAL experiment at sqrts=183 GeV were used to
search for Higgs bosons which are predicted by the Standard Model and various
extensions, such as general models with two Higgs field doublets and the
Minimal Supersymmetric Standard Model (MSSM). The data correspond to an
integrated luminosity of approximately 54pb-1. None of the searches for neutral
and charged Higgs bosons have revealed an excess of events beyond the expected
background. This negative outcome, in combination with similar results from
searches at lower energies, leads to new limits for the Higgs boson masses and
other model parameters. In particular, the 95% confidence level lower limit for
the mass of the Standard Model Higgs boson is 88.3 GeV. Charged Higgs bosons
can be excluded for masses up to 59.5 GeV. In the MSSM, mh > 70.5 GeV and mA >
72.0 GeV are obtained for tan{beta}>1, no and maximal scalar top mixing and
soft SUSY-breaking masses of 1 TeV. The range 0.8 < tanb < 1.9 is excluded for
minimal scalar top mixing and m{top} < 175 GeV. More general scans of the MSSM
parameter space are also considered.Comment: 49 pages. LaTeX, including 33 eps figures, submitted to European
Physical Journal
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