Independent sets of some graphs associated to commutative rings

Let $G=(V,E)$ be a simple graph. A set $S\subseteq V$ is independent set of $G$, if no two vertices of $S$ are adjacent. The independence number $\alpha(G)$ is the size of a maximum independent set in the graph. %An independent set with cardinality Let $R$ be a commutative ring with nonzero identity and $I$ an ideal of $R$. The zero-divisor graph of $R$, denoted by $\Gamma(R)$, is an undirected graph whose vertices are the nonzero zero-divisors of $R$ and two distinct vertices $x$ and $y$ are adjacent if and only if $xy = 0$. Also the ideal-based zero-divisor graph of $R$, denoted by $\Gamma_I(R)$, is the graph which vertices are the set {x\in R\backslash I | xy\in I \quad for some \quad y\in R\backslash I\} and two distinct vertices $x$ and $y$ are adjacent if and only if $xy \in I$. In this paper we study the independent sets and the independence number of $\Gamma(R)$ and $\Gamma_I(R)$.Comment: 27 pages. 22 figure

Diptheria vaccine awareness survey among the general populace of Kaduna State

Aim: The aim of the study is to find the knowledge of Kaduna state populace on diphtheria vaccine which is the most effective way of tackling the disease as the Diphtheria antitoxin is not readily available for use in the country. Method: A survey conducted with a designed questionnaire at a confidence level of 95%, confidence interval of 12.5 showed Kaduna State populace’s responses on diphtheria, its vaccine and booster doses, the questionnaire was self administered and responses were collated using simple descriptive statistics. Results: A total number of 64 people responded; majority (37 of 64) were from the child bearing age fifty six, 56(88%), fifty nine, 59 (92%) were vaccinated against diphtheria but only eighteen, 18 (28%) knew about its booster doses. Twenty eight, 28 (45%) took their children for vaccine but only fourteen, 14 (11%) ever took them to receive the booster dose from among the respondents. Conclusion: Kaduna state residents have generally inconsequential awareness on diphtheria, its prevention and management. Key words: Diphtheria toxin; Diphtheria toxoid; Vaccine; Knowledge; Populac

Structure of Rat Kidneys Following Microwave Accelerated Fixation

In contrast to fixation of tissue in externally heated fixative, microwave-irradiation can generate uniform internal heat, which is of utmost importance for successful fixation of biological tissue. To evaluate the effectiveness of microwave-accelerated chemical fixation, we compared the structure of rat kidney fixed by a conventional method and a microwave-accelerated method, by scanning and transmission electron microscopy. Following perfusion, rat kidney pieces 1-2 mm in size were irradiated in Karnovsky\u27s fixative in a domestic Amana microwave oven, till the temperature of the fixative reached 45-50°C. For conventional fixation, tissue pieces were fixed overnight at room temperature in the same fixative. Both types of samples were processed further for electron microscopy using identical protocols. The microwave fixed samples showed excellent preservation of structure comparable to the samples fixed by the conventional method. Glomeruli and the renal tubules showed normal morphology with no cellular swelling. The cytoplasm and nuclear matrix of the epithelial cells was uniformly dense. Other fixation sensitive organelles like mitochondria and Golgi apparatus showed superior preservation with continuous membranes. These results demonstrate that microwave accelerated chemical fixation results in excellent preservation of tissue structure, reduces processing time significantly and is therefore a practical alternative to conventional protocols

Tolerance to freezing stress in Cicer accessions under controlled and field conditions

Freezing tolerance was determined in 5 annual wild Cicer and 225 Cicer arietinum L. accessions, grown both in field and controlled conditions. In controlled conditions, the temperature was decreased 5°C daily to achieve -20°C. Field trial was conducted at Urmia, Iran. In general, 'kabuli' chickpeas were more susceptible to freezing stress than 'desi' chickpeas. Some 'kabuli' types such as FLIP 93-261C and x03TH21 which presented high freezing tolerance during early seedling stage, withstood -15.6°Cwithout snow cover. Based on severity score data, the highest freezing tolerance sources were all accessions of Cicer echinospermum and Cicer reticulatum and 15 lines from C. arietinum germplasm. The results obtained in controlled conditions were approximately confirmed in the field conditions. The most resistant genotypes to freezing stress were wild accessions of ILWC 81, ILWC 106, ILWC 139, ILWC 181, ILWC 235, and cultivated lines, Sel 96 TH 11404, Sel 96 TH 11439, Sel 96 TH 11488, Sel 98 TH 11518, x03TH21 and FLIP 93-261C. Our results indicated the possibility of autumn sowing of chickpea in the high plateaus of Iran

Satellite TVRO system reception under tropical weather conditions effects

TVRO systems suffers from the tropical weather conditions effects. This paper evaluate the system based on its effects of that conditions. This paper presents a Satellite TVRO system reception with regard to various weather conditions effects such as day time, night time as well as clear sky and rain sky conditions have been highlighted. The Geo arc that has been derived from such system represent the application of TVRO. The TVRO structures a Geo-arc formation and formulation in terms of satellite signals losses

"Test me and treat me" - attitudes to vitamin D deficiency and supplementation: a qualitative study

© 2015 BMJ Open, "Test me and treat me"-attitudes to vitamin D deficiency and supplementation: a qualitative study. This manuscript version is made available under the Creative Commons Attribution Licens

Voltage Stability Analysis of Grid-Connected Wind Farms with FACTS: Static and Dynamic Analysis

Recently, analysis of some major blackouts and failures of power system shows that voltage instability problem has been one of the main reasons of these disturbances and networks collapse. In this paper, a systematic approach to voltage stability analysis using various techniques for the IEEE 14-bus case study, is presented. Static analysis is used to analyze the voltage stability of the system under study, whilst the dynamic analysis is used to evaluate the performance of compensators. The static techniques used are Power Flow, V–P curve analysis, and Q–V modal analysis. In this study, Flexible Alternating Current Transmission system (FACTS) devices- namely, Static Synchronous Compensators (STATCOMs) and Static Var Compensators (SVCs) - are used as reactive power compensators, taking into account maintaining the violated voltage magnitudes of the weak buses within the acceptable limits defined in ANSI C84.1. Simulation results validate that both the STATCOMs and the SVCs can be effectively used to enhance the static voltage stability and increasing network loadability margin. Additionally, based on the dynamic analysis results, it has been shown that STATCOMs have superior performance, in dynamic voltage stability enhancement, compared to SVCs