Andreev reflection from non-centrosymmetric superconductors and Majorana bound state generation in half-metallic ferromagnets

We study Andreev reflection at an interface between a half metal and a superconductor with spin-orbit interaction. While the absence of minority carriers in the half metal makes singlet Andreev reflection impossible, the spin-orbit interaction gives rise to triplet Andreev reflection, i.e., the reflection of a majority electron into a majority hole or vice versa. As an application of our calculation, we consider a thin half metal film or wire laterally attached to a superconducting contact. If the half metal is disorder free, an excitation gap is opened that is proportional to the spin-orbit interaction strength in the superconductor. For electrons with energy below this gap a lateral half-metal--superconductor contact becomes a perfect triplet Andreev reflector. We show that the system supports localized Majorana end states in this limit.Comment: 14 pages, 3 figure

Understanding the dynamical structure of pulsating stars. HARPS spectroscopy of the delta Scuti stars rho Pup and DX Cet

High-resolution spectroscopy is a powerful tool to study the dynamical structure of pulsating stars atmosphere. We aim at comparing the line asymmetry and velocity of the two delta Sct stars rho Pup and DX Cet with previous spectroscopic data obtained on classical Cepheids and beta Cep stars. We obtained, analysed and discuss HARPS high-resolution spectra of rho Pup and DX Cet. We derived the same physical quantities as used in previous studies, which are the first-moment radial velocities and the bi-Gaussian spectral line asymmetries. The identification of f=7.098 (1/d) as a fundamental radial mode and the very accurate Hipparcos parallax promote rho Pup as the best standard candle to test the period-luminosity relations of delta Sct stars. The action of small-amplitude nonradial modes can be seen as well-defined cycle-to-cycle variations in the radial velocity measurements of rho Pup. Using the spectral-line asymmetry method, we also found the centre-of-mass velocities of rho Pup and DX Cet, V_gamma = 47.49 +/- 0.07 km/s and V_gamma = 25.75 +/- 0.06 km/s, respectively. By comparing our results with previous HARPS observations of classical Cepheids and beta Cep stars, we confirm the linear relation between the atmospheric velocity gradient and the amplitude of the radial velocity curve, but only for amplitudes larger than 22.5 km/s. For lower values of the velocity amplitude (i.e., < 22.5 km/s), our data on rho Pup seem to indicate that the velocity gradient is null, but this result needs to be confirmed with additional data. We derived the Baade-Wesselink projection factor p = 1.36 +/- 0.02 for rho Pup and p = 1.39 +/- 0.02 for DX Cet. We successfully extended the period-projection factor relation from classical Cepheids to delta Scuti stars.Comment: Accepted for publication in A&A (in press

Local equilibrium in heavy-ion collisions: microscopic analysis of a central cell versus infinite matter

REVTEX, 27 pages incl. 10 figures and 3 tables; Phys. Rev. C (in press) Journal-ref: Phys.Rev. C62 (2000) 064906. We study the local equilibrium in the central V = 125 fm3 cell in heavy-ion collisions at energies from 10.7 A GeV (AGS) to 160 A GeV (SPS) calculated in the microscopic transport model. In the present paper the hadron yields and energy spectra in the cell are compared with those of infinite nuclear matter, as calculated within the same model. The agreement between the spectra in the two systems is established for times t >= 10 fm/c in the central cell. The cell results do not deviate noticeably from the infinite matter calculations with rising incident energy, in contrast to the apparent discrepancy with predictions of the statistical model (SM) of an ideal hadron gas. The entropy of this state is found to be very close to the maximum entropy, while hadron abundances and energy spectra differ significantly from those of the SM

An Optimized Data Management Model for Maternal Mortality in Bayelsa State

Maternal Mortality Rate (MMR) is the quantity of maternal deaths in a given duration per 100,000 of reproductive aged (15-49) women. This amounts to both the obstetric risk and the rate of recurrence at which women are unprotected to this risk. In Bayelsa State, the maternal mortality has high rates. The driving reasons for death are related with hypertensive disorder, severe bleeding, infection and other complications of delivery that could be avoided. This research aims to develop a maternal mortality system using Data mining techniques; estimation of maternal mortality rate in Otuasega Cottage Hospital in Ogbia Local Government Area in Bayelsa State was carried out by analyzing the causes of death during pregnancy; Naive Bayes was used in Bayes Server to classify Hypertensive diseases into preeclampsia and gestational, identifying the symptoms and risk factors. Among other causes of maternal death evaluated, Hypertensive disease was the highest cause of maternal death in Bayelsa State between 2012 to 2018. We developed a Bayesian maternal mortality estimation model, that catches increasing speeds and deceleration in the rate of progress in the maternal death rate. Result shows that the trend was as low as 2 maternal deaths in every 202 live births in 2012 but increased to 12 per 210 live births in 2016. The maternal mortality rate continued its upward trend and increased to 14 deaths per 172 live births in the year 2018. Maternal mortality rate which was very low have increased significantly, and most death were caused by Hypertensive, followed by bleeding, complications and little of infections. Keywords: Naïve Bayes, Bayesian Estimation Model, Maternal Mortality DOI: 10.7176/CEIS/10-5-02 Publication date:June 30th 201

Isothermal remanent magnetization of Greenland ice: Preliminary results

The magnetic mineral content of wind“transported dust should reflect atmospheric transport dynamics and conditions in its source areas, and could thus be used as an environmental proxy. To test the feasibility of determining the magnetic mineral content in polar ice, isothermal remanent magnetization (IRM) was measured on a small suite of Greenland ice samples of Holocene (interglacial) and Last Glacial Maximum (LGM) age. Although the extremely low dust concentrations limit weak field (susceptibility) measurements, all samples contained an easily measurable concentration of magnetic minerals that can be estimated using IRM intensity provided that special precautions are used. IRM experiments at liquid nitrogen temperatures indicate ice magnetic properties which are consistent with that expected from varying concentrations of magnetite or maghemite. Interestingly, the Holocene ice samples tend to have higher magnetic concentrations, despite having much lower total polar dust contents, than the few LGM ice samples tested thus far

24 hour-ambulatory blood pressure and heart rate profiles in diagnosing orthostatic hypotension in Parkinson’s disease and Multiple System Atrophy

Background:24-hour ambulatory blood pressure and heart rate monitoring (24hr-ABPM) can provide vital information on circadian blood pressure (BP) profiles, which are commonly abnormal in Parkinson’s disease with and without autonomic failure (PD+AF and PD) and multiple system atrophy (MSA). 24hr-ABPM has not been directly compared between these disorders regarding cardiovascular autonomic function. We aim to determine the usefulness of 24hr-ABPM with diary compared to Head-up Tilting (HUT) in diagnosing orthostatic hypotension (OH) in these patients. Methods: 74 patients (23 MSA,18 PD+AF,33 PD) underwent cardiovascular autonomic screening followed by 24hr-ABPM with diary. Standing tests were included during 24hr-ABPM. The sensitivity and specificity in detecting OH from the 24hr-ABPM standing test were compared with HUT. Results: There was no difference in OH during HUT between MSA and PD+AF (p>0.05). MSA and PD+AF had a higher proportion of abnormal BP circadian rhythms compared to PD (p0.05). Patients were divided into groups with (OH+) and without OH (OH-) on HUT. Using the standing test during 24hr-ABPM, a SBP fall of >20 mmHg showed a sensitivity and specificity of 82% and 100 % (AUC 0.91, 95% CI 0.84-0.98) in differentiating OH+ from OH-, respectively. Conclusions:PD+AF and MSA patients had similar circadian BP patterns suggesting that autonomic dysfunction influences abnormal BP circadian patterns similarly in these disorders. The higher sensitivity and specificity in detecting OH using a SBP fall of >20 mmHg compared to a DBP fall of >10 mmHg during standing test supports its usefulness to assess autonomic function in MSA and PD

Ultrathin Metallic Coatings Can Induce Quantum Levitation between Nanosurfaces

There is an attractive Casimir-Lifshitz force between two silica surfaces in a liquid (bromobenze or toluene). We demonstrate that adding an ultrathin (5-50{\AA}) metallic nanocoating to one of the surfaces results in repulsive Casimir-Lifshitz forces above a critical separation. The onset of such quantum levitation comes at decreasing separations as the film thickness decreases. Remarkably the effect of retardation can turn attraction into repulsion. From that we explain how an ultrathin metallic coating may prevent nanoelectromechanical systems from crashing together.Comment: 4 pages, 5 figure

Retardation turns the van der Waals attraction into Casimir repulsion already at 3 nm

Casimir forces between surfaces immersed in bromobenzene have recently been measured by Munday et al. Attractive Casimir forces were found between gold surfaces. The forces were repulsive between gold and silica surfaces. We show the repulsion is due to retardation effects. The van der Waals interaction is attractive at all separations. The retardation driven repulsion sets in already at around 3 nm. To our knowledge retardation effects have never been found at such a small distance before. Retardation effects are usually associated with large distances

Equilibrium and nonequilibrium effects in nucleus nucleus collisions

Abstract: Local thermal and chemical equilibration is studied for central AqA collisions at 10.7 160 AGeV in the Ultrarelativis- . tic Quantum Molecular Dynamics model UrQMD . The UrQMD model exhibits strong deviations from local equilibrium at the high density hadron string phase formed during the early stage of the collision. Equilibration of the hadron resonance matter is established in the central cell of volume Vs125 fm3 at later stages, tG10 fmrc, of the resulting quasi-isentropic expansion. The thermodynamical functions in the cell and their time evolution are presented. Deviations of the UrQMD quasi-equilibrium state from the statistical mechanics equilibrium are found. They increase with energy per baryon and lead to a strong enhancement of the pion number density as compared to statistical mechanics estimates at SPS energies. PACS: 25.75.-q; 24.10.Lx; 24.10.Pa; 64.30.q