The origin of some Manganese oxide ores: with special reference to the deposits of Sinai

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Wigner Distribution Function Approach to Dissipative Problems in Quantum Mechanics with emphasis on Decoherence and Measurement Theory

We first review the usefulness of the Wigner distribution functions (WDF), associated with Lindblad and pre-master equations, for analyzing a host of problems in Quantum Optics where dissipation plays a major role, an arena where weak coupling and long-time approximations are valid. However, we also show their limitations for the discussion of decoherence, which is generally a short-time phenomenon with decay rates typically much smaller than typical dissipative decay rates. We discuss two approaches to the problem both of which use a quantum Langevin equation (QLE) as a starting-point: (a) use of a reduced WDF but in the context of an exact master equation (b) use of a WDF for the complete system corresponding to entanglement at all times

Exposure to violence and PTSD symptoms among Somali women

Posttraumatic stress disorder (PTSD) symptoms, exposure to traumatic stressors, and health care utilization were examined in 84 women attending a primary health care clinic in Mogadishu, Somalia. The Somalia-Posttraumatic Diagnostic Scale was used in this active warzone to measure symptoms. Nearly all women reported high levels of confrontations with violence; half described being exposed to a potentially traumatizing event. Nearly one third had significant PTSD symptoms. Compared to those who did not, women who reported exposure to a traumatic stressor reported more confrontations with violence (7.1 vs. 3.3; p < . 001), health complaints (3.8 vs. 2.9; p = .03), and nearly 3 times as much (p = .03) health service utilization. A potentially traumatizing event was found to be a simplified proxy for assessing mental health distress in women attending a primary health care facility in highly insecure, unpredictable, resource-limited settings

Assessment of the Potential Impact and Cost-effectiveness of Self-Testing for HIV in Low-Income Countries.

Studies have demonstrated that self-testing for human immunodeficiency virus (HIV) is highly acceptable among individuals and could allow cost savings, compared with provider-delivered HIV testing and counseling (PHTC), although the longer-term population-level effects are uncertain. We evaluated the cost-effectiveness of introducing self-testing in 2015 over a 20-year time frame in a country such as Zimbabwe

Quantum measurement and decoherence

Distribution functions defined in accord with the quantum theory of measurement are combined with results obtained from the quantum Langevin equation to discuss decoherence in quantum Brownian motion. Closed form expressions for wave packet spreading and the attenuation of coherence of a pair of wave packets are obtained. The results are exact within the context of linear passive dissipation. It is shown that, contrary to widely accepted current belief, decoherence can occur at high temperature in the absence of dissipation. Expressions for the decoherence time with and without dissipation are obtained that differ from those appearing in earlier discussions

Nuclear-spin relaxation of 207^{207}Pb in ferroelectric powders

Motivated by a recent proposal by O. P. Sushkov and co-workers to search for a P,T-violating Schiff moment of the $^{207}$Pb nucleus in a ferroelectric solid, we have carried out a high-field nuclear magnetic resonance study of the longitudinal and transverse spin relaxation of the lead nuclei from room temperature down to 10 K for powder samples of lead titanate (PT), lead zirconium titanate (PZT), and a PT monocrystal. For all powder samples and independently of temperature, transverse relaxation times were found to be $T_2\approx 1.5$ms, while the longitudinal relaxation times exhibited a temperature dependence, with $T_1$ of over an hour at the lowest temperatures, decreasing to $T_1\approx 7$s at room temperature. At high temperatures, the observed behavior is consistent with a two-phonon Raman process, while in the low temperature limit, the relaxation appears to be dominated by a single-phonon (direct) process involving magnetic impurities. This is the first study of temperature-dependent nuclear-spin relaxation in PT and PZT ferroelectrics at such low temperatures. We discuss the implications of the results for the Schiff-moment search.Comment: 6 pages, 4 figure

N-terminal pro-B-type natriuretic peptide and the prediction of primary cardiovascular events: results from 15-year follow-up of WOSCOPS

&lt;b&gt;Aims:&lt;/b&gt;To test whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) was independently associated with, and improved the prediction of, cardiovascular disease (CVD) in a primary prevention cohort. &lt;b&gt;Methods and results:&lt;/b&gt; In the West of Scotland Coronary Prevention Study (WOSCOPS), a cohort of middle-aged men with hypercholesterolaemia at a moderate risk of CVD, we related the baseline NT-proBNP (geometric mean 28 pg/mL) in 4801 men to the risk of CVD over 15 years during which 1690 experienced CVD events. Taking into account the competing risk of non-CVD death, NT-proBNP was associated with an increased risk of all CVD [HR: 1.17 (95% CI: 1.11–1.23) per standard deviation increase in log NT-proBNP] after adjustment for classical and clinical cardiovascular risk factors plus C-reactive protein. N-terminal pro-B-type natriuretic peptide was more strongly related to the risk of fatal [HR: 1.34 (95% CI: 1.19–1.52)] than non-fatal CVD [HR: 1.17 (95% CI: 1.10–1.24)] (P= 0.022). The addition of NT-proBNP to traditional risk factors improved the C-index (+0.013; P &lt; 0.001). The continuous net reclassification index improved with the addition of NT-proBNP by 19.8% (95% CI: 13.6–25.9%) compared with 9.8% (95% CI: 4.2–15.6%) with the addition of C-reactive protein. N-terminal pro-B-type natriuretic peptide correctly reclassified 14.7% of events, whereas C-reactive protein correctly reclassified 3.4% of events. Results were similar in the 4128 men without evidence of angina, nitrate prescription, minor ECG abnormalities, or prior cerebrovascular disease. &lt;b&gt;Conclusion:&lt;/b&gt; N-terminal pro-B-type natriuretic peptide predicts CVD events in men without clinical evidence of CHD, angina, or history of stroke, and appears related more strongly to the risk for fatal events. N-terminal pro-B-type natriuretic peptide also provides moderate risk discrimination, in excess of that provided by the measurement of C-reactive protein

The Rotating Quantum Vacuum

We derive conditions for rotating particle detectors to respond in a variety of bounded spacetimes and compare the results with the folklore that particle detectors do not respond in the vacuum state appropriate to their motion. Applications involving possible violations of the second law of thermodynamics are briefly addressed.Comment: Plain TeX, 10 pages (to appear in PRD

Thermodynamics of phantom black holes in Einstein-Maxwell-Dilaton theory

A thermodynamic analysis of the black hole solutions coming from the Einstein-Maxwell-Dilaton theory (EMD) in 4D is done. By consider the canonical and grand-canonical ensemble, we apply standard method as well as a recent method known as Geometrothermodynamics (GTD). We are particularly interested in the characteristics of the so called phantom black hole solutions. We will analyze the thermodynamics of these solutions, the points of phase transition and their extremal limit. Also the thermodynamic stability is analyzed. We obtain a mismatch of the between the results of the GTD method when compared with the ones obtained by the specific heat, revealing a weakness of the method, as well as possible limitations of its applicability to very pathological thermodynamic systems. We also found that normal and phantom solutions are locally and globally unstable, unless for certain values of the coupled constant of the EMD action. We also shown that the anti-Reissner-Nordstrom solution does not posses extremal limit nor phase transition points, contrary to the Reissner-Nordstrom case.Comment: 23 pages, version accepted for publication in Physical Review

Decoherence of electron beams by electromagnetic field fluctuations

Electromagnetic field fluctuations are responsible for the destruction of electron coherence (dephasing) in solids and in vacuum electron beam interference. The vacuum fluctuations are modified by conductors and dielectrics, as in the Casimir effect, and hence, bodies in the vicinity of the beams can influence the beam coherence. We calculate the quenching of interference of two beams moving in vacuum parallel to a thick plate with permittivity $\epsilon(\omega)=\epsilon_{0}+i 4\pi\sigma/\omega$. In case of an ideal conductor or dielectric $(|\epsilon|=\infty)$ the dephasing is suppressed when the beams are close to the surface of the plate, because the random tangential electric field $E_{t}$, responsible for dephasing, is zero at the surface. The situation is changed dramatically when $\epsilon_{0}$ or $\sigma$ are finite. In this case there exists a layer near the surface, where the fluctuations of $E_{t}$ are strong due to evanescent near fields. The thickness of this near - field layer is of the order of the wavelength in the dielectric or the skin depth in the conductor, corresponding to a frequency which is the inverse electron time of flight from the emitter to the detector. When the beams are within this layer their dephasing is enhanced and for slow enough electrons can be even stronger than far from the surface