114 research outputs found
Time-Resolved Two-Photon Quantum Interference
The interference of two independent single-photon pulses impinging on a beam
splitter is analysed in a generalised time-resolved manner. Different aspects
of the phenomenon are elaborated using different representations of the
single-photon wave packets, like the decomposition into single-frequency field
modes or spatio-temporal modes matching the photonic wave packets. Both
representations lead to equivalent results, and a photon-by-photon analysis
reveals that the quantum-mechanical two-photon interference can be interpreted
as a classical one-photon interference once a first photon is detected. A novel
time-dependent quantum-beat effect is predicted if the interfering photons have
different frequencies. The calculation also reveals that full two-photon fringe
visibility can be achieved under almost any circumstances by applying a
temporal filter to the signal.Comment: 6 pages, 4 figure
Shifts in the Properties of the Higgs Boson from Radion Mixing
We examine how mixing between the Standard Model Higgs boson, , and the
radion present in the Randall-Sundrum model of localized gravity modifies the
expected properties of the Higgs boson. In particular, we demonstrate that the
total and partial decay widths of the Higgs, as well as the branching
fraction, can be substantially altered from their Standard Model expectations.
The remaining branching fractions are modified less than \lsim 5% for most of
the parameter space volume.Comment: 17 pages, 7 figs., LaTex; revised versio
Supersymmetry Without Prejudice
We begin an exploration of the physics associated with the general
CP-conserving MSSM with Minimal Flavor Violation, the pMSSM. The 19 soft SUSY
breaking parameters in this scenario are chosen so as to satisfy all existing
experimental and theoretical constraints assuming that the WIMP is a
conventional thermal relic, ie, the lightest neutralino. We scan this parameter
space twice using both flat and log priors for the soft SUSY breaking mass
parameters and compare the results which yield similar conclusions. Detailed
constraints from both LEP and the Tevatron searches play a particularly
important role in obtaining our final model samples. We find that the pMSSM
leads to a much broader set of predictions for the properties of the SUSY
partners as well as for a number of experimental observables than those found
in any of the conventional SUSY breaking scenarios such as mSUGRA. This set of
models can easily lead to atypical expectations for SUSY signals at the LHC.Comment: 61 pages, 24 figs. Refs., figs, and text added, typos fixed; This
version has reduced/bitmapped figs. For a version with better figs please go
to http://www.slac.stanford.edu/~rizz
Challenges of Cryptocurrencies Forensics – A Case Study of Investigating, Evidencing and Prosecuting Organised Cybercriminals
This article presents policing challenges of investigating, evidencing and prosecuting organized cybercriminals for the crimes committed using cryptocurrencies such as Bitcoin. A set of best practices is discussed to tackle these challenges in real world investigations. This work is a result of collaboration with a number of stakeholders the policing and judicial ecosystem with the objective of investigating and prosecuting the new generation of organised cybercriminals. Concrete scenarios of using Bitcoins in a range of cybercrimes were developed as part of this project and the devices were analysed to extract evidence to assist prosecution of organised cybercriminals. We have also presented our return of experience for various stages of digital forensics analysis of devices used in Bitcoin transactions
Multi-fingered haptic palpation utilizing granular jamming stiffness feedback actuators
This paper describes a multi-fingered haptic palpation method using stiffness feedback actuators for simulating tissue palpation procedures in traditional and in robot-assisted minimally invasive surgery. Soft tissue stiffness is simulated by changing the stiffness property of the actuator during palpation. For the first time, granular jamming and pneumatic air actuation are combined to realize stiffness modulation. The stiffness feedback actuator is validated by stiffness measurements in indentation tests and through stiffness discrimination based on a user study. According to the indentation test results, the introduction of a pneumatic chamber to granular jamming can amplify the stiffness variation range and reduce hysteresis of the actuator. The advantage of multi-fingered palpation using the proposed actuators is proven by the comparison of the results of the stiffness discrimination performance using two-fingered (sensitivity: 82.2%, specificity: 88.9%, positive predicative value: 80.0%, accuracy: 85.4%, time: 4.84 s) and single-fingered (sensitivity: 76.4%, specificity: 85.7%, positive predicative value: 75.3%, accuracy: 81.8%, time: 7.48 s) stiffness feedback
Multilevel psychometric properties of the AHRQ hospital survey on patient safety culture
<p>Abstract</p> <p>Background</p> <p>The Agency for Healthcare Research and Quality (AHRQ) <it>Hospital Survey on Patient Safety Culture </it>was designed to assess staff views on patient safety culture in hospital settings. The purpose of this study was to examine the multilevel psychometric properties of the survey.</p> <p>Methods</p> <p>Survey data from 331 U.S. hospitals with 2,267 hospital units and 50,513 respondents were analyzed to examine the psychometric properties of the survey's items and composites. Item factor loadings, intraclass correlations (ICCs), design effects, internal consistency reliabilities, and multilevel confirmatory factor analyses (MCFA) were examined as well as intercorrelations among the survey's composites.</p> <p>Results</p> <p>Psychometric analyses confirmed the multilevel nature of the data at the individual, unit and hospital levels of analysis. Results provided overall evidence supporting the 12 dimensions and 42 items included in the AHRQ <it>Hospital Survey on Patient Safety Culture </it>as having acceptable psychometric properties at all levels of analysis, with a few exceptions. The Staffing composite fell slightly below cutoffs in a number of areas, but is conceptually important given its impact on patient safety. In addition, one hospital-level model fit indicator for the Supervisor/Manager Expectations & Actions Promoting Patient Safety composite was low (CFI = .82), but all other psychometrics for this scale were good. Average dimension intercorrelations were moderate at .42 at the individual level, .50 at the unit level, and .56 at the hospital level.</p> <p>Conclusions</p> <p>Psychometric analyses conducted on a very large database of hospitals provided overall support for the patient safety culture dimensions and items included in the AHRQ <it>Hospital Survey on Patient Safety Culture</it>. The survey's items and dimensions overall are psychometrically sound at the individual, unit, and hospital levels of analysis and can be used by researchers and hospitals interested in assessing patient safety culture. Further research is needed to study the criterion-related validity of the survey by analysing the relationship between patient safety culture and patient outcomes and studying how to improve patient safety culture.</p
Reduced density matrices and entanglement entropy in free lattice models
We review the properties of reduced density matrices for free fermionic or
bosonic many-particle systems in their ground state. Their basic feature is
that they have a thermal form and thus lead to a quasi-thermodynamic problem
with a certain free-particle Hamiltonian. We discuss the derivation of this
result, the character of the Hamiltonian and its eigenstates, the
single-particle spectra and the full spectra, the resulting entanglement and in
particular the entanglement entropy. This is done for various one- and
two-dimensional situations, including also the evolution after global or local
quenches.Comment: 33 pages, 18 figures, minor changes, references added. Review article
for the special issue "Entanglement entropy in extended systems" in J. Phys.
A Job is Not a Hobby: The Judicial Revival of Corporate Paternalism and its Problematic Implications
Treatment options for small cell lung cancer – do we have more choice?
Small cell lung cancer (SCLC) is a significant health problem worldwide because of its high propensity for relapse. This review discusses existing and future therapies for the treatment of SCLC
Adjuvant goserelin and ovarian preservation in chemotherapy treated patients with early breast cancer: results from a randomized trial
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