Groups with star free commuting graphs

Let $G$ be a group and $Z(G)$ be its center. We associate a commuting graph ${\Gamma}(G)$, whose vertex set is $G\setminus Z(G)$ and two distinct vertices are adjacent if they commute. We say that ${\Gamma}(G)$ is strong $k$ star free if the $k$ star graph is not a subgraph of ${\Gamma}(G)$. In this paper, we characterize all strong $5$ star free commuting graphs. As a byproduct, we classify all strong claw-free graphs. Also, we prove that the set of all non-abelian groups whose commuting graph is strong $k$ star free is finite.Comment: 12 pages, 4 figure

On the spectrum of generalized H-join operation constrained by indexing maps -- I

Fix $m \in \mathbb N$. A new generalization of the $H$-join operation of a family of graphs $\{G_1, G_2, \dots, G_k\}$ constrained by indexing maps $I_1,I_2,\dots,I_k$ is introduced as $H_m$-join of graphs, where the maps $I_i:V(G_i)$ to $[m]$. Various spectra, including adjacency, Laplacian, and signless Laplacian spectra, of any graph $G$, which is a $H_m$-join of graphs is obtained by introducing the concept of $E$-main eigenvalues. More precisely, we deduce that in the case of adjacency spectra, there is an associated matrix $E_i$ of the graph $G_i$ such that a $E_i$-non-main eigenvalue of multiplicity $m_i$ of $A(G_i)$ carry forward as an eigenvalue for $A(G)$ with the same multiplicity $m_i$, while an $E_i$-main eigenvalue of multiplicity $m_i$ carry forward as an eigenvalue of $G$ with multiplicity at least $m_i - m$. As a corollary, the universal adjacency spectra of some families of graphs is obtained by realizing them as $H_m$-joins of graphs. As an application, infinite families of cospectral families of graphs are found

A REVIEW ON NATURAL COMPOSITES

Natural fibers have attracted the interest to engineers, researchers, professionals and scientists all over the world as an alternative reinforcement, because of its superior properties such as high specific strength, low weight, low cost, fairly good mechanical properties, non abrasive, eco-friendly and bio-degradable characteristics. A brief review has been carried out to make use of the natural fibers (such as abaca, jute, cotton, coir, Glass fiber etc) abundantly available in India. This paper presents a review on the mechanical properties of Abaca, Jute, Glass fibre

A study on the efficacy and adverse effects of methotrexate in psoriasis patients in a tertiary care centre

Background: Psoriasis is a common, chronic and recurrent inflammatory disease of the skin. Methotrexate has been used in patient with psoriasis, a folic acid antagonist interfering with purine pathway and the mechanism of action in psoriasis is immune modulation and anti-inflammation. So, this study aims at monitoring the efficacy and adverse effects of methotrexate in south Indian patients with psoriasis attending a tertiary care hospital.Methods: It is a prospective, observational study conducted for a period of one year in subjects of either sex having psoriasis. Methotrexate was initiated in a single weekly oral dose of 5mg to 25mg. The efficacy was evaluated using psoriasis Area and Severity Index (PASI) score in all patients before starting methotrexate therapy and the end of first month, third month and sixth month of therapy. Adverse reaction was monitored.Results: All 40 psoriasis patients after treatment with methotrexate therapy showed improved  skin lesions by falling PASI scoring at the end of first, third and sixth month of treatment. None of the patients in our study had pulmonary toxicity, life threatening adverse effects which required hospitalization.Conclusions: Use of methotrexate in the treatment of psoriasis in this study was found to be safe and highly efficacious and caused minimal adverse effects and it was well tolerated

Source localization in shallow ocean using a vertical array of acoustic vector sensors

This paper introduces a new approach to 3D localisation of a narrowband acoustic source in a shallow ocean using acoustic vector sensors (AVS). Assuming a horizontally stratified and range-independent model of the ocean, it is shown that the azimuth of the source can be determined from the estimates of the horizontal components of the acoustic intensity vector obtained from the measurements of an AVS. The range and depth of the source could then be estimated through a 2D search to match the computed complex acoustic intensity vector expressed as a function of these parameters with its estimate obtained from the AVS measurements. However the search in range is computationally intensive as the range parameter is unbounded. We propose an alternative approach employing a vertical array of AVS, based on eigen-decomposition of the spatial correlation matrix of the data vector, leading to a closed form solution for the range parameter. The source depth is then estimated through a 1D search of this bounded parameter

Effectiveness of taichi exercises on stress among college students at selected colleges, Salem

A Study was conducted to Evaluate the Effectiveness of Taichi Exercises on stress among college students at Selected colleges, Salem. The design adopted was true-experimental pre-test post-test control group design. Setting of the study was Vinayaka Mission Kirubananda Variyar College of Engineering (Experimental group) and Sri Annapoorna College of Engineering (Control Group). The screening was done with the use of Perceived Stress Scale (PSS). Then the subjects were separated based on their stress level. 60 samples were drawn through simple random sampling technique (Lottery method without replacement).Level of stress was assessed by four point rating scale through structured self-administered questionnaire. Taichi Exercises was administered for 21 consecutive days. Then Post-test was done. The data gathered were analysed by descriptive and inferential statistical method. The findings revealed that during pre-test, all 30 (100%), of the samples had moderate stress in Experimental and control group. During post-test, in experimental group, 10(33.33%) and 20(66.67%) of the college students had mild and moderate stress, whereas in control group, all 30(100%) of the samples had moderate stress. The mean difference in the level of stress between pre test and post test of experimental group was 24.4 and the estimated paired ‘t’ value 18.29 was most significantly higher than table value 2.05 at p≤ 0.05 level. Hence H1 was retained. The post test mean difference in the level of stress between the experimental and control group was 23.1 and the estimated ‘t’ value 8.39 was most significantly higher than table value 2.06 at p≤ 0.05 level. Hence H2 was retained, which shows that the Taichi Exercises was effective in reducing the stress among college students. There was no significant association (p≤0.05) between the stress among college students in experimental group and control group. Hence H3 was rejected. The study concluded that Taichi Exercises was effective and innovative therapeutic approach, and a cost effective technique in establishing, maintaining and promoting a good sense of psychological wellbeing among students

A Study on Clinical Profile of Rodenticide Poisoning at Government Stanley Hospital, Chennai - 600 001

INTRODUCTION: Rodenticide toxicity is one of the common modes of poisoning encountered in our part of the country. It is cheap and easily available in the market, in various forms such as powder, cake, paste etc. The rodenticides manufactured by standard companies has a fixed concentration of chemical, whereas the locally made rodenticides do not have such fixed concentration. Rodenticide toxicity can range from asymptomatic presentation to life threatening complications and death, based on the amount and type of rodenticide ingested. As compared to older and conventional rodenticides, the newer and modern rodenticides are more toxic to human beings. There are case studies and case reports that highlight the toxic effects of various types of rodenticides in human beings. This study is about the clinical profile and the outcome of patients with rodenticide poisoning. AIMS AND OBJECTIVES: 1. To study the clinical profile of patients admitted with rodenticide poisoning at IMCU, Govt. Stanley hospital, Chennai. 2. To assess the morbidity, mortality and clinical outcome of those patients. MATERIALS AND METHODS: Place of Study: This study has been carried out at the toxicology unit of Intensive Medical Care Unit and Medical wards of Govt. Stanley hospital, Chennai. Study Period: One year (From November 2011 to November 2012). Study Design: This is a Retrospective and Prospective observational study. Inclusion Criteria: 1. Any patient admitted with rodenticide intake, 2. Age of the patients > 13 years. Exclusion Criteria: 1. Mixed poisons, 2. Chronic liver disease, 3. Alcohol intake within 24 hours before admission, 4. Patients on drugs like anticoagulants, antiplatelets, 5. Patients with bleeding disorders, 6. Acute diarrhoeal disease, 7. Patients with known coronary artery disease RESULTS: The total number of patients included in the study was 421. But only 303 patient’s data was finally included for the analysis. The remaining 118 patients did not give consent, absconded or were discharged prematurely before the completion of investigations and were excluded from the study. The remaining 303 patients’ data were taken for final analysis. CONCLUSION: Rodenticide poisoning, though commonly remarked as ‘rat never dies’; can be fatal to humans when the specific ingredient is consumed in a lethal dose. Although there are ample studies about individual types of rodenticide, to our best of knowledge, we could not find any other study in the literature that compares the various types. Having said that, we must say the comparative study has yielded few striking facts. • Zinc phosphide is the most prevalent poison in our study, but their mortality and morbidity rate is very low • Super warfarin poisoning, the second common rodenticide in ourstudy, produced significant derangement in coagulation parameters, but failed to manifest clinically. (In short, it is rather benign) • Yellow phosphorous, although leastcommon in our study, had a significant impact on the patient’s outcome. The mortality rate is a whopping 50% among the consumed. Rodenticide poisoning, though encountered every day, had so many nuances and intricacies, which became apparent to us after analysing their clinical profile. Indeed, it is a very satisfying experience in a common poison