Modelling the components of binaries in Hyades: The dependence of the mixing-length parameter on stellar mass

We present our findings based on a detailed analysis for the binaries of the Hyades, in which the masses of the components are well known. We fit the models of components of a binary system to the observations so as to give the observed total V and B-V of that system and the observed slope of the main-sequence in the corresponding parts. According to our findings, there is a very definite relationship between the mixing-length parameter and the stellar mass. The fitting formula for this relationship can be given as $alpha = 9.19 (M/M_sun-0.74)^{0.053}-6.65$, which is valid for stellar masses greater than 0.77 M_sun. While no strict information is gathered for the chemical composition of the cluster, as a result of degeneracy in the colour-magnitude diagram, by adopting Z=0.033 and using models for the components of 70 Tau and theta^2 Tau we find the hydrogen abundance to be X=0.676 and the age to be 670 Myr. If we assume that Z=0.024, then X=0.718 and the age is 720 Myr. Our findings concerning the mixing length parameter are valid for both sets of the solution. For both components of the active binary system V818 Tau, the differences between radii of the models with Z=0.024 and the observed radii are only about 4 percent. More generally, the effective temperatures of the models of low mass stars in the binary systems studied are in good agreement with those determined by spectroscopic methods.Comment: 11 pages, 7 figures, accepted for publication in MNRA

Quantum Group Covariance and the Braided Structure of Deformed Oscillators

The connection between braided Hopf algebra structure and the quantum group covariance of deformed oscillators is constructed explicitly. In this context we provide deformations of the Hopf algebra of functions on SU(1,1). Quantum subgroups and their representations are also discussed.Comment: 12 pages, to be published in JM

Foreign Direct Investment and Inequality in Productivity across Countries

Using data for 93 countries for a period from 1970 to 2000, this paper examines the effects of foreign direct investment (FDI) on cross-country differences in productivity. We construct a spatial Gini coefficient of labor productivity across countries, and weighted indices of FDI and gross domestic investment (GDI). We then examine their time series properties to explore the relations of FDI and GDI with productivity. Although we find little evidence of FDI flows – which have increased manifold in last three decades – reducing inequality in productivity for the entire sample, our analysis shows that these three variables are cointegrated for developed, high and middle income developing countries, indicating existence of a long-run equilibrium relationships between FDI, GDI and productivity. FDI seems to reduce inequality in productivity among high and middle income developing countries while it widens productivity gaps among developed countries in the long-run though these effects are statistically significant only for high income developing countries. In middle income developing countries, higher GDI seems to have significant effect in reducing productivity differences. Granger causality tests further suggest that FDI causes productivity differences among petroleum exporting countries. Furthermore, GDI granger causes FDI in high income countries and productivity differences Granger cause FDI into the middle income developing countries.

Convex Hulls under Uncertainty

We study the convex-hull problem in a probabilistic setting, motivated by the need to handle data uncertainty inherent in many applications, including sensor databases, location-based services and computer vision. In our framework, the uncertainty of each input site is described by a probability distribution over a finite number of possible locations including a \emph{null} location to account for non-existence of the point. Our results include both exact and approximation algorithms for computing the probability of a query point lying inside the convex hull of the input, time-space tradeoffs for the membership queries, a connection between Tukey depth and membership queries, as well as a new notion of \some-hull that may be a useful representation of uncertain hulls

The contrasting oceanography of the Rhodes Gyre and the Central Black Sea

The Rhodes Gyre, a prominent feature of the oceanography of the eastern Mediterranean, is modelled as a vertical, continuous flow, cylindrical reactor illuminated during the day at its upper end. If the Gyre is supposed to be in a steady state whilst the concentrations, C, of a chemical are being measured, the nett rate of formation or consumption of the chemical is given by -w d C/d z + u d C/d r, where w is the upward velocity of the water in the vertical, z , direction and u is the velocity of the water in the radial, r, direction. The behaviour of w and u is analysed to show that the Gyre may be used as a field laboratory in which rates of chemical change may be derived from depth profiles together with values of the surface velocities of the Gyre waters. In contrast, the central Black Sea is modelled as an ideal, strongly stratified sea in which the nett rates of formation or consumption of chemicals under steady state conditions are given by Ds d2C/ds 2, where s is the water density and Ds is an eddy diffusion coefficient. Computations reveal that, given better knowledge of its eddy diffusion coefficients, the Black Sea can also be treated as a field laboratory where rates of reaction mediated by bacteria may be derived from depth profiles

On Geodesically Convex Formulations for the Brascamp-Lieb Constant

We consider two non-convex formulations for computing the optimal constant in the Brascamp-Lieb inequality corresponding to a given datum and show that they are geodesically log-concave on the manifold of positive definite matrices endowed with the Riemannian metric corresponding to the Hessian of the log-determinant function. The first formulation is present in the work of Lieb [Lieb, 1990] and the second is new and inspired by the work of Bennett et al. [Bennett et al., 2008]. Recent work of Garg et al. [Ankit Garg et al., 2017] also implies a geodesically log-concave formulation of the Brascamp-Lieb constant through a reduction to the operator scaling problem. However, the dimension of the arising optimization problem in their reduction depends exponentially on the number of bits needed to describe the Brascamp-Lieb datum. The formulations presented here have dimensions that are polynomial in the bit complexity of the input datum

Effect of different levels of royal jelly on biochemical parameters of swimmers

This study aims to investigate the effects of different levels of royal jelly supplementation on biochemical parameters in swimmers. Randomly selected 40 male swimmers aged 18 to 25 years attending the same trainings were recruited. Swimmers were assigned to 4 groups each with 10 subjects. Varying amounts of royal jelly (2, 1 g and 500 mg) were given to the 1st, 2nd and 3rd groups and placebo (corn starch) to the 4th group. Participants were trained by swimming totally 20 km in 2 h on 5 days a week for 4 weeks. Resting blood samples were taken before royal jelly administration and after 30 days of application. Then biochemical analyses were performed. Different levels of royal jelly were found to be ineffective on glucose, total cholesterol, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, lactate dehydrogenase (LDH), creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels of the swimmers. Blood urea nitrogen (BUN) and creatinine levels increased after the training program, and BUN level was higher in the group receiving 500 mg royal jelly than those in the other groups. The increment in creatinine levels was higher in those groups receiving higher amounts of royal jelly after the training. A supplementation of 500 mg, 1 and 2 g/day of royal jelly throughout the 30 day-exercise program was not significantly effective in the swimmers. Also, due to its high amino acid content, BUN and creatinine levels tended to increase.Key words: Royal jelly, swimming, exercise, biochemical parameters, ergogenic aids