An Exact Solution for Static Scalar Fields Coupled to Gravity in (2+1)(2+1)-Dimensions

We obtain an exact solution for the Einstein's equations with cosmological constant coupled to a scalar, static particle in static, "spherically" symmetric background in 2+1 dimensions.Comment: 9 pages. Replaced by a revised versio

Gravitational Collapse of Inhomogeneous Dust in (2+1) Dimensions

We examine the gravitational collapse of spherically symmetric inhomogeneous dust in (2+1) dimensions, with cosmological constant. We obtain the analytical expressions for the interior metric. We match the solution to a vacuum exterior. We discuss the nature of the singularity formed by analyzing the outgoing radial null geodesics. We examine the formation of trapped surfaces during the collapse.Comment: Accepted for publication in CQ

Разработка математической модели узла гидрофторирования производства гексафторида урана

Cadmium poses a major environmental and human health threat because of its constant release through anthropogenic activities. A need, therefore, exists for cost-effective remediation procedures. Phytoremediation, the use of plants to extract contaminants from soils and groundwater, has revealed great potential. However, it is limited by the fact that plants need time, nutrient supply and, moreover, have a limited metal uptake capacity. Synthetic chelators have shown positive effects in enhancing heavy metal extraction through phytoremediation, but they have also revealed a vast number of negative side-effects. The objective of this research was to investigate the use of humic acids as an alternative to synthetic chelators. Humic acids were applied to a cadmium-contaminated soil at various dosages, and the uptake of cadmium into Nicotiana tabacum SR-1 was determined in relation to the amounts of total and bioavailable cadmium in the soil. It was found that the theoretical bioavailability of cadmium, as determined by diethylenetriaminepentaacetic acid (DTPA) extraction, did not change, but its plant uptake was enhanced significantly, in some cases up to 65%. Humic acids added at a rate of 2 gkg(exp -1) soil increased the cadmium concentration in the shoots from 30.9 to 39.9 mg kg(exp -1). A possible reason for this enhancement is the decrease in pH, resulting in higher cadmium availability. Another possibility taken into account is that plants may take up cadmium complexes with humic acid fragments, which result from microbiological degradation or, self-dissociation

Validation of Pre-Adolescent Decision-Making Competence in Turkish students

The objective of this study was to adapt the Pre-Adolescent Decision-Making Competence Test to Turkish, which was originally developed in English by Weller, Levin, Rose and Bossard (2012) for assessing decision-making competence of children between the ages of 9 and 14. For this purpose; a) the test and instructions were translated into Turkish, b) the Turkish test was administered to a group of 398 students as a pilot, c) retest was administered to a group of 97 students, and finally, d) a group of 382 students was subject to a norm study. The Confirmatory Factor Analysis model created by the data of the pilot administration was well adapted, and one-factor model was verified for construct validity. As the construct of the test was altered, a Confirmatory Factor Analysis was performed on the data obtained from the norm study. A construct similar to that acquired from the data of the first test administration and the results obtained have even relatively better fit indices. Although the reliability values were less than what was expected, Cronbach's Alpha coefficient of internal consistency was similar to the results obtained from the original test

Phytosiderophore release does not relate well with zinc efficiency in different bread wheat genotypes

Using six bread wheat genotypes (Triticum aestivum L. cvs. Dagdas-94, Gerek-79, BDME-10, SBVD 1-21, SBVD 2-22 and Partizanka Niska) and one durum wheat genotype (Triticum durum L. cv. Kunduru-1149) experiments were carried out to study the relationship between the rate of phytosiderophore release and susceptibility of genotypes to zinc (Zn) deficiency during 15 days of growth in nutrient solution with (1 µM Zn) and without Zn supply. Among the genotypes, Dagdas-94 and Gerek-79 are Zn efficient, while the others are highly susceptible to Zn deficiency, when grown on severely Zn deficient calcareous soils in Turkey. Similar to the field observations, visual Zn deficiency symptoms, such as whitish-brown lesions on leaf blades occurred first and severely in durum wheat Kunduru- 1149 and bread wheats Partizanka Niska, BDME-10, SBVD 1-21 and SBVD 2-22. Visual Zn deficiency symptoms were less severe in the bread wheats Gerek-79 and particularly Dagdas-94. These genotypic differences in susceptibility to Zn deficiency were not related to the concentrations of Zn in shoots or roots. All bread wheat genotypes contained similar Zn concentration in the dry matter. In all genotypes supplied adequately with Zn, the rate of phytosiderophore release was very low and did not exceed 0.5 µmol/48 plants/3 h. However, under Zn deficiency the release of phytosiderophores increased in all bread wheat genotypes, but not in the durum wheat genotype. The corresponding rates of phytosiderophore release in Zn deficient durum wheat genotype were 1.2 µmol and in Zn deficient bread wheat genotypes ranged between 8.6 µmol for Partizanka Niska to 17.4 µmol for SBVD 2-22. In Dagdas-94, the most Zn efficient genotype, the highest rate of phytosiderophore release was 14.8 µmol. The results indicate that the release rate of phytosiderophores does not relate well with the susceptibility of bread wheat genotypes to Zn deficiency. Root uptake and root-to-shoot transport of Zn and particularly internal utilization of Zn may be more important mechanisms involved in expression of Zn efficiency in bread wheat genotypes than release of phytosiderophores.This study was supported by the NATO Scientific framework of the Science for Stability Programme