Magnetic Structure of Rapidly Rotating FK Comae-Type Coronae

We present a three-dimensional simulation of the corona of an FK Com-type rapidly rotating G giant using a magnetohydrodynamic model that was originally developed for the solar corona in order to capture the more realistic, non-potential coronal structure. We drive the simulation with surface maps for the radial magnetic field obtained from a stellar dynamo model of the FK Com system. This enables us to obtain the coronal structure for different field topologies representing different periods of time. We find that the corona of such an FK Com-like star, including the large scale coronal loops, is dominated by a strong toroidal component of the magnetic field. This is a result of part of the field being dragged by the radial outflow, while the other part remains attached to the rapidly rotating stellar surface. This tangling of the magnetic field,in addition to a reduction in the radial flow component, leads to a flattening of the gas density profile with distance in the inner part of the corona. The three-dimensional simulation provides a global view of the coronal structure. Some aspects of the results, such as the toroidal wrapping of the magnetic field, should also be applicable to coronae on fast rotators in general, which our study shows can be considerably different from the well-studied and well-observed solar corona. Studying the global structure of such coronae should also lead to a better understanding of their related stellar processes, such as flares and coronal mass ejections, and in particular, should lead to an improved understanding of mass and angular momentum loss from such systems.Comment: Accepted to ApJ, 10 pages, 6 figure

Preliminary studies on using LAB strains isolated from spontaneous sauerkraut fermentation in combination with mineral salt, herbs and spices in sauerkraut and sauerkraut juice fermentations

The use of mineral salt, herbs and spices in combination with isolated lactic acid bacteria strains in sauerkraut fermentation was studied. Mineral salt differs from ordinary salt because NaCl is partially replaced by KCl. The mineral salt contains 28% KCl and 57% NaCl. The final NaCl content in the sliced white cabbage mixture was 0.5%. In approximately 20 hours the pH dropped to the desired level. All the pressed sauerkraut juices had a good microbiological quality. The sensory quality of all pressed juices was found to be either good or acceptable

First-principles calculation of positron annihilation characteristics at metal vacancies

Annihilation characteristics for positrons trapped at metal vacancies are calculated from first principles. The calculations are based on different implementations of the two-component density-functional theory, and different numerical methods to solve the ensuing Kohn-Sham equations have been employed. The convergence of the positron annihilation characteristics calculated within different schemes is discussed, and the positron lifetimes obtained are compared with experiment.Peer reviewe

Vacancy-formation energies for fcc and bcc transition metals

We have performed first-principles total-energy calculations for vacancy formation energies in six bcc (V, Cr, Nb, Mo, Ta, W) and six fcc (Ni, Cu, Pd, Ag, Pt, Au) transition metals within the local-density approximation of the density-functional theory. The calculations are done using the full-potential linear-muffin-tin-orbital method employing the supercell technique. The calculated vacancy formation energies are in good agreement with experiments especially for the fcc metals, but in the case of V and Cr the calculated values are significantly larger than the experimental ones.Peer reviewe

Stellar activity as noise in exoplanet detection I. Methods and application to solar-like stars and activity cycles

The detection of exoplanets using any method is prone to confusion due to the intrinsic variability of the host star. We investigate the effect of cool starspots on the detectability of the exoplanets around solar-like stars using the radial velocity method. For investigating this activity-caused "jitter" we calculate synthetic spectra using radiative transfer, known stellar atomic and molecular lines, different surface spot configurations, and an added planetary signal. Here, the methods are described in detail, tested and compared to previously published studies. The methods are also applied to investigate the activity jitter in old and young solar-like stars, and over a solar-like activity cycles. We find that the mean full jitter amplitude obtained from the spot surfaces mimicking the solar activity varies during the cycle approximately between 1 m/s and 9 m/s. With a realistic observing frequency a Neptune mass planet on a one year orbit can be reliably recovered. On the other hand, the recovery of an Earth mass planet on a similar orbit is not feasible with high significance. The methods developed in this study have a great potential for doing statistical studies of planet detectability, and also for investigating the effect of stellar activity on recovered planetary parameters.Comment: Accepted to MNRA

Prospective association between tobacco smoking and death by suicide : a competing risks hazard analysis in a large twin cohort with 35-year follow-up

Background. The relationship between smoking and suicide remains controversial. Method. A total of 16 282 twin pairs born before 1958 in Finland and alive in 1974 were queried with detailed health and smoking questionnaires in 1975 and 1981, with response rates of 89% and 84%. Smoking status and dose, marital, employment, and socio-economic status, and indicators of psychiatric and somatic illness were assessed at both time points. Emergent psychiatric and medical illness and vital status, including suicide determined by forensic autopsy, were evaluated over 35-year follow-up through government registries. The association between smoking and suicide was determined in competing risks hazard models. In twin pairs discordant for smoking and suicide, the prospective association between smoking and suicide was determined using a matched case-control design. Results. Smokers had a higher cumulative suicide incidence than former or never smokers. Heavy smokers had significantly higher suicide risk [hazard ratio (HR) 3.47, 95% confidence interval (CI) 2.31-5.22] than light smokers (HR 2.30, 95% CI 1.61-3.23) (p = 0.017). Compared with never smokers, smokers, but not former smokers, had increased suicide risk (HR 2.56, 95% CI 1.43-4.59), adjusting for depressive symptoms, alcohol and sedative-hypnotic use, and excluding those who developed serious somatic or psychiatric illness. In twin pairs discordant for smoking and suicide, suicide was more likely in smokers [odds ratio (OR) 6.0, 95% CI 2.06-23.8]. Conclusions. Adults who smoked tobacco were more likely to die by suicide, with a large, dose-dependent effect. This effect remained after consideration of many known predictors of suicide and shared familial effects, consistent with the hypothesis that exposure to tobacco smoke increases the risk of suicide.Peer reviewe

First-principles calculation of positron lifetimes and affinities in perfect and imperfect transition-metal carbides and nitrides

First-principles electronic structure and positron-state calculations for transition-metal carbides and nitrides are performed. Perfect NaCl structures as well as structures with metal or carbon/nitrogen vacancies are considered. The positron affinities and lifetimes are determined. The trends are discussed and the results are compared with recent positron lifetime measurements for group-IV and -V refractory metal carbides. The present analysis suggests, contradictory to an earlier interpretation, that positrons are trapped and annihilated at both carbon and metal vacancies. The concentration of metal vacancies detected by positron annihilation methods is probably very low, below the sensitivity limit of other experimental methods.Peer reviewe

Explaining job satisfaction and job control: a survey among finnish psychiatrists

Background: Job satisfaction has a major impact on mental health and job performance. Additionally, expected work satisfaction may influence choice of specialization within medicine. Methods: A postal survey was conducted in 2009 among the members (N=1398) of Finnish Psychiatric Association. Out of the members 1132 were still working-aged. All in all 64.8% (N=738) of the working-aged members returned the survey. Only psychiatrists and residents were included in the final cohort of the study (N=665). Factors associated to work satisfaction were studied and a principal component analysis was conducted on factors reported to disturb working. The correlations of factors scores with job satisfaction and job-control were analyzed. Spearman correlation coefficients were calculated between factor scores and work satisfaction. Results: Most respondents (73.8%) were satisfied with their work. Job satisfaction showed a negative correlation with increase in pace of work (rho=-0.24, p&lt;0.001). Job control correlated positively with job satisfaction (rho=0.46, p&lt;0.001). &quot;Working conditions&quot; factor explained 28.6%, &quot;leadership&quot; 8.8%, &quot;failure without support&quot; 7.8%, fear at work 6.5% and &quot;patient records&quot; factors 5.9% of the variation of perceived harmful factors at work. &quot;Working conditions&quot; and &quot;leadership&quot; factors showed the strongest and most significant negative correlations with job satisfaction (rho= -0.45, p&lt;0.001, rho=-0.32, p&lt;0.001, respectively. &quot;Working conditions&quot; associated strongly and significantly with job control (rho=-0.57, p&lt;0.001). Conclusion: Job satisfaction may be better than expected among psychiatrists considering the findings of prevalence estimates of burnout in various other studies. However, employers should put emphasis on matching employers and type of work to promote well-being of their employees.</p

9286 Stars: An Agglomeration of Stellar Polarization Catalogs

This is a revision. The revisions are minor. The new version of the catalog should be used in preference to the old. The most serious error in the older version was that $\theta_diff$ was incorrect, being sometimes far too large, for Reiz and Franco entries; the correct values are all zero for that reference. We present an agglomeration of stellar polarization catalogs with results for 9286 stars. We have endeavored to eliminate errors, provide accurate (arcsecond) positions, sensibly weight multiple observations of the same star, and provide reasonable distances. This catalog is included as an ASCII file (catalog.txt) in the source of this submission.Comment: The most serious error in the older version was that $\theta_diff$ was incorrect, being sometimes far too large, for Reiz and Franco entries; the correct values are all zero for that reference. 11 pages, no figures. Accepted for Astronomical Journal. Catalog also available as an ASCII file by anonymous FTP from ftp://vermi.berkeley.edu/pub/polcat/p14.ou

Value Efficiency Analysis for Incorporating Preference Information in Data Envelopment Analysis

We develop a procedure and the requisite theory for incorporating preference information in a novel way in the efficiency analysis of Decision Making Units. The efficiency of Decision Making Units is defined in the spirit of Data Envelopment Analysis (DEA), complemented with Decision Maker's preference information concerning the desirable structure of inputs and outputs. Our procedure begins by aiding the Decision Maker in searching for the most preferred combination of inputs and outputs of Decision Making Units (for short, Most Preferred Solution) which are efficient in DEA. Then, assuming that the Decision Maker's Most Preferred Solution maximizes his/her underlying (unknown) value function at the moment when the search is terminated, we approximate the indifference contour of the value function at this point with its possible tangent hyperplanes. Value Efficiency scores are then calculated for each Decision Making Unit comparing the inefficient units to units having the same value as the Most Preferred Solution. The resulting Value Efficiency scores are optimistic approximations of the true scores. The procedure and the resulting efficiency scores are immediately applicable to solving practical problems