One-loop Quantum Gravity in Schwarzschild Spacetime

The quantum theory of linearized perturbations of the gravitational field of a Schwarzschild black hole is presented. The fundamental operators are seen to be the perturbed Weyl scalars $\dot\Psi_0$ and $\dot\Psi_4$ associated with the Newman-Penrose description of the classical theory. Formulae are obtained for the expectation values of the modulus squared of these operators in the Boulware, Unruh and Hartle-Hawking quantum states. Differences between the renormalized expectation values of both $\bigl| \dot\Psi_0 \bigr|^2$ and $\bigl| \dot\Psi_4 \bigr|^2$ in the three quantum states are evaluated numerically.Comment: 39 pages, 11 Postscript figures, using revte

Comparison of techniques for computing shell-model effective operators

Different techniques for calculating effective operators within the framework of the shell model using the same effective interaction and the same excitation spaces are presented. Starting with the large-basis no-core approach, we compare the time-honored perturbation-expansion approach and a model-space truncation approach. Results for the electric quadrupole and magnetic dipole operators are presented for $^6$Li. The convergence trends and dependence of the effective operators on differing excitation spaces and Pauli Q-operators is studied. In addition, the dependence of the electric-quadrupole effective charge on the harmonic-oscillator frequency and the mass number, for A=5,6, is investigated in the model-space truncation approach.Comment: 18 pages. REVTEX. 4 PostScript figure

Associations between neck musculoskeletal complaints and work related factors among public service computer workers in Kaunas

Objectives:Information technologies have been developing very rapidly, also in the case of occupational activities. Epidemiological studies have shown that employees, who work with computers, are more likely to complain of musculoskeletal disorders (MSD). The aim of this study was to evaluate associations between neck MSD and individual and work related factors. Materials and Methods: The investigation which consisted of two parts - a questionnaire study (using Nordic Musculoskeletal questionnaire and Copenhagen Psychosocial Questionnaire) and a direct observation (to evaluate ergonomic work environment using RULA method) was carried out in three randomly selected public sector companies of Kaunas. The study population consisted of 513 public service office workers. Results: The survey showed that neck MSDs were very common in the investigated population. The prevalence rate amounted to 65.7%. According to our survey neck MSDs were significantly associated with older age, bigger work experience, high quantitative and cognitive job demands, working for longer than 2 h without taking a break as well as with higher ergonomic risk score. The fully adjusted model working for longer than 2 h without taking a break had the strongest associations with neck complaints. Conclusion: It was confirmed, that neck MSDs were significantly associated with individual factors as well as conditions of work, therefore, preventive acions against neck complaints should be oriented at psychosocial and ergonomic work environment as well as at individual factors

Validity of rating scale measures of voice quality

The validity of perceptual measures of vocal quality has been neglected in studies of voice, which focus more commonly on rater reliability. Validity depends in part on reliability, because an unreliable test does not measure what it is intended to measure. However, traditional measures of rating reliability only partially represent interrater agreement, because they cannot reflect variations or patterns of agreement for specific voice samples. In this paper the likelihood that two raters would agree in their ratings of a single voice is examined, for each voice in five previously gathered data sets. Results do not support the continued assumption that traditional rating procedures produce useful indices of listeners' perceptions. Listeners agreed very poorly in the midrange of scales for breathiness and roughness, and mean ratings in the midrange of such scales did not represent the extent to which a voice possesses a quality, but served only to indicate that listeners disagreed. Techniques like analysis by synthesis or judgment of similarity avoid decomposing quality into constituent dimensions, and do not require a listener to compare an external stimulus to an unstable internal representation, thus decreasing the error in measures of quality. Modeling individual differences in perception can increase the variance accounted for in models of quality, further reducing the error in perceptual measures. Thus such techniques may provide valid alternatives to current approaches

Cluster Hybrid Monte Carlo Simulation Algorithms

We show that addition of Metropolis single spin-flips to the Wolff cluster flipping Monte Carlo procedure leads to a dramatic {\bf increase} in performance for the spin-1/2 Ising model. We also show that adding Wolff cluster flipping to the Metropolis or heat bath algorithms in systems where just cluster flipping is not immediately obvious (such as the spin-3/2 Ising model) can substantially {\bf reduce} the statistical errors of the simulations. A further advantage of these methods is that systematic errors introduced by the use of imperfect random number generation may be largely healed by hybridizing single spin-flips with cluster flipping.Comment: 16 pages, 10 figure

A Burgessian critique of nominalistic tendencies in contemporary mathematics and its historiography

We analyze the developments in mathematical rigor from the viewpoint of a Burgessian critique of nominalistic reconstructions. We apply such a critique to the reconstruction of infinitesimal analysis accomplished through the efforts of Cantor, Dedekind, and Weierstrass; to the reconstruction of Cauchy's foundational work associated with the work of Boyer and Grabiner; and to Bishop's constructivist reconstruction of classical analysis. We examine the effects of a nominalist disposition on historiography, teaching, and research.Comment: 57 pages; 3 figures. Corrected misprint

Point Source Polarimetry with the Gemini Planet Imager: Sensitivity Characterization with T5.5 Dwarf Companion HD 19467 B

Detecting polarized light from self-luminous exoplanets has the potential to provide key information about rotation, surface gravity, cloud grain size, and cloud coverage. While field brown dwarfs with detected polarized emission are common, no exoplanet or substellar companion has yet been detected in polarized light. With the advent of high contrast imaging spectro-polarimeters such as GPI and SPHERE, such a detection may now be possible with careful treatment of instrumental polarization. In this paper, we present 28 minutes of H-band GPI polarimetric observations of the benchmark T5.5 companion HD 19467 B. We detect no polarization signal from the target, and place an upper limit on the degree of linear polarization of p_(CL99.73%) ⩽ 2.4%. We discuss our results in the context of T dwarf cloud models and photometric variability

Defining malnutrition: a plea to rethink

In a recent consensus report in Clinical Nutrition the undernourished category of malnutrition was proposed to be defined and diagnosed on the basis of a low BMI or unintentional weight loss combined with low BMI or FFMI with certain cut off points. The definition was endorsed by ESPEN despite recent endorsement of a very different definition. The approach aims to assess whether nutritional intake is sufficient but is imprecise because a low BMI does not always indicate malnutrition and individuals with increasing BMI's may have decreasing FFM's. The pathophysiology of individuals, considered to be malnourished in rich countries and in areas with endemic malnutrition, results predominantly from deficient nutrition combined with infection/inflammation. Both elements jointly determine body composition and function and consequently outcome of disease, trauma or treatment. When following the consensus statement only an imprecise estimate is acquired of nutritional intake without knowing the impact of inflammation. Most importantly, functional abilities are not assessed. Consequently it will remain uncertain how well the individual can overcome stressful events, what the causes are of dysfunction, how to set priorities for treatment and how to predict the effect of nutritional support. We therefore advise to consider the pathophysiology of malnourished individuals leading to inclusion of the following elements in the definition of malnutrition: a disordered nutritional state resulting from a combination of inflammation and a negative nutrient balance, leading to changes in body composition, function and outcome. A precise diagnosis of malnutrition should be based on assessment of these element

Genetically Determined Plasma Lipid Levels and Risk of Diabetic Retinopathy: A Mendelian Randomization Study.

Results from observational studies examining dyslipidemia as a risk factor for diabetic retinopathy (DR) have been inconsistent. We evaluated the causal relationship between plasma lipids and DR using a Mendelian randomization approach. We pooled genome-wide association studies summary statistics from 18 studies for two DR phenotypes: any DR (N = 2,969 case and 4,096 control subjects) and severe DR (N = 1,277 case and 3,980 control subjects). Previously identified lipid-associated single nucleotide polymorphisms served as instrumental variables. Meta-analysis to combine the Mendelian randomization estimates from different cohorts was conducted. There was no statistically significant change in odds ratios of having any DR or severe DR for any of the lipid fractions in the primary analysis that used single nucleotide polymorphisms that did not have a pleiotropic effect on another lipid fraction. Similarly, there was no significant association in the Caucasian and Chinese subgroup analyses. This study did not show evidence of a causal role of the four lipid fractions on DR. However, the study had limited power to detect odds ratios less than 1.23 per SD in genetically induced increase in plasma lipid levels, thus we cannot exclude that causal relationships with more modest effect sizes exist