Three-dimensional black holes with scalar hair coupled to a Maxwell-like electrodynamics

By consideration of a Einstein-dilaton non-linear charged gravitating system, it has been shown that this theory is confronted with the problem of indeterminacy. It means that the number of independent differential equations is one less than the number of unknowns. To overcome this problem, the power-law and exponential ansatz functions have been used, separately. Through solving the field equations, in the presence of a Coulomb-like electric field, it has been found that this theory includes two novel classes of charged black holes (BHs) with unusual asymptotic behavior, for each ansatz. It has been found that, under some circumstances, both of the ansatz functions lead to the same results. The novel exact solutions show BHs with one horizon, two horizons and without horizon. Using a Smarr-type mass formula validity of the first law of BH thermodynamics (FLT) has been proved, after calculating the thermodynamic and conserved quantities. Making use of thermodynamical and geometrical approaches, thermal stability of the BHs has been analyzed. Results of the aforementioned methods have been compared by use of the plots.Comment: 18 pages with 6 figures. Accepted by MPL

Bioaccumulation of heavy metals in eight fish species of the Khur-e Khuran International Wetland in the Persian Gulf, Iran

Heavy metals are among the most toxic pollutants in aquatic ecosystems. This study was conducted to evaluate the concentration of heavy metals viz. lead, cadmium, chromium, zinc, cobalt, and copper in eight commercial fishes of Khur-e Khuran international wetland (KIW), Iran. The results showed that the highest concentration of heavy metals attributed to Zn as 176.5 µg g-1 dry weight in Platycephalus indicus and the lowest to Pb as 0.12 µg g-1 dry weight in Sillago sihama. Average concentrations of heavy metals in eight examined fish species were 29.15, 49.73, 1.39, 0.45, 1.43 and 1.56 µg g-1 dry weight for Cu, Zn, Cd, Pb, Co and Cr, respectively. The results also show that measured values of most heavy metals in some examined fishes of KIW were higher than those maximum permissible limit (MPL) according to international standards. The high concentrations of some metals in some examined fishes of KIW may be due to industrial and residential activities in adjacent coast i.e. in mainland and Qeshm Island, and marine traffi

Effects of Environmental Factors on the Growth, Optical Density and Biomass of the Green Algae Chlorella Vulgaris in Outdoor Conditions

Effect of environmental factors on the growth of the Chlorella vulgaris was studied. C. vulgaris was  cultivated in sterilized natural seawater enriched with F/2-Si medium. Then grow in bucket, tub and photobioreactor (PBR) in outdoor condition. The daily routine work consisted of culture checkups of optical density, biomass gains, atmosphere lux, culture lux, atmosphere temperature and culture temperature  were recorded. The highest biomass yields were (3.0 μg/ml-1) in December and (2.01 μg/ml-1) in November in PBR. The highest deviation was in atmosphere lux in time 8:30 (± 117.7) and lowest  deviation was in atmosphere temperature in time 15:00 (± 1.0499). Optical density (OD) indicated that the best growth of C. vulgaris in outdoor condition was obtained in 650 lux and also it increased with increasing amount of lux. Tub report of C. vulgaris showed different growing behaviors at the various concentration of light and at the different temperatures. Algal production in outdoor PBR is relatively inexpensive, but is only suitable for a few, fast-growing specie. Finally, this fact is noteworthy that in outdoor conditions, temperature and light have important role in growth of C. vulgaris in present study.  ©JASEMKeywords: Chlorella vulgaris, Biomass, Photobioreactor, Growth

A Regularized Interior-Point Method for Constrained Linear Least Squares

RÉSUMÉ : Nous proposons une méthode de points intérieurs non réalisable pour le problème aux moindres carrés linéaire avec contraintes basée sur la régularisation primale-duale de problèmes quadratiques convexes de Friedlander et Orban (2012). À chaque itération, la méthode effectue une factorisation LDLT creuse d’une matrice symétrique et quasi définie. Cette matrice est uniformément bornée et non singulière. Nous établissons des conditions sous lesquelles la méthode produit une solution du problème original. La régularisation nous permet d’éliminer l’hypothèse que les gradients actifs sont linéairement indépendants. Bien que l’implémentation proposée ici repose sur une factorisation, elle ouvre la voie à une implémentation itérative dans laquelle on résout un problème aux moindres carrés régularisé sans contraintes de façon inexacte à chaque itération. Nous illustrons notre approche sur plusieurs applications qui mettent en évidence ses avantages.----------ABSTRACT : We propose an infeasible interior-point algorithm for constrained linear least-squares problems based on the primal-dual regularization of convex programs of Friedlander and Orban (2012). At each iteration, the sparse LDLT factorization of a symmetric quasi-definite matrix is computed. This coefficient matrix is shown to be uniformly bounded and nonsingular. We establish conditions under which a solution of the original problem is recovered. The regularization allows us to dispense with the assumption that the active gradients are linearly independent. Although the implementation described here is factorization based, it paves the way for a matrix-free implementation in which a regularized unconstrained linear least-squares problem is solved at each iteration. We report on computational experience and illustrate the potential advantages of our approach

Factor structure and invariance of the pain catastrophizing scale in patients with chronic pain and their spouses

PURPOSE: This study was designed to investigate the equivalency and factor structure of the patients and significant others' version of pain catastrophizing scales in patients with chronic pain and their spouses who are not in pain. METHOD: Participants were 142 married couples in which 1 spouse reported chronic musculoskeletal pain. Confirmatory factor analyses were used to compare 4 models of pain catastrophizing, and to examine the invariance of the factor structure of the PCS-Patient version and the PCS-Significant other version in patients with chronic pain and their spouses. RESULTS: The results indicated that the 2-factor oblique model provided an adequate fit to the data of both patients with chronic pain and their spouses who are not in pain. Moreover, it was found that when gender was controlled, the hypothesized factor structures of the PCS-patient version and the PCS-Significant other version were invariant. Indeed, it was revealed that the PCS-Patient version and the PCS-Significant other version measure the same factors in couples in which 1 of them have a chronic pain condition. CONCLUSIONS: The findings of the current study showed that the 2-factor oblique model is the best fit in both samples (i.e., patients with chronic pain and their spouses). Therefore, it can be suggested that these versions can be used among patients and their spouses and the findings regarding them can be compared. (PsycInfo Database Record (c) 2020 APA, all rights reserved)

The effects of froth depth and impeller speed on gas dispersion properties and metallurgical performance of an industrial self-aerated flotation machine

In self-aerated flotation machines, the gas rate depends on operational variables (e.g. froth depth and impeller speed), pulp properties (e.g. solid content and viscosity), and reagent addition (e.g. type and concentration of frother). The gas rate has a strong correlation with the flotation performance by influencing the gas dispersion properties and froth retention time. A factorial experimental design was used to study how the gas dispersion properties, the froth retention time, and the flotation performance respond to changes in froth depth and impeller speed (as the most common operational variables). An in-depth understanding of the effects of impeller speed and froth depth on the gas dispersion properties, especially the bubble surface area flux and froth retention time, is necessary to improve operating strategies for self-aerated flotation machines. All experiments were carried out in a 50 m(3) self-aerated flotation cell in an iron ore processing plant. The results showed that the froth depth affected the metallurgical performance mostly via changing the froth retention time. The impeller speed had two important impacts on the metallurgical performance via varying both the froth retention time and the bubble surface area flux in the froth and pulp zones, respectively. The interaction effects of the froth depth and impeller speed were also established. This allowed us to develop a strategy for operating self-aerated flotation machines based on varying the froth depth and impeller speed with regard to the cell duty