Microprocessor-based simulation of sampled data systems with/without a hold device using a set of sample-and-hold functions and Dirac delta functions

In the present work, Dirac delta function (DF) set and sample-and-hold functions (SHF) set are used for microprocessor-based simulation of discrete time as well as sample-and-hold systems. Such simulations are useful for identification of control systems with known input and output sequence. The presented method utilizes operational matrices of different orders in the DF and SHF domain to develop different operational transfer functions. A few open-loop as well as closed-loop systems have been studied and the simulation results obtained are compared with exact solutions derived with the help of z-transform analysis. Experiments have also been carried out to establish the validity of the proposal.     

External and Internal Irreversibility

The article attempts to clarify the meaning of internal and external irreversibility using the example of a heat engine. It has been proved that the efficiency of an internally reversible but externally irreversible engine is almost 50% of the efficiency of a totally reversible engine.     

Copper and ceruloplasmin levels in relation to total thiols and GST in type 2 diabetes mellitus patients

Presence of oxidative stress in type 2 diabetes mellitus (DM) is well proved. Current study was undertaken to know the relation between fasting plasma glucose (FPG) and copper along with antioxidants like total thiols and ceruloplasmin, and antioxidant enzyme glutathione S transferase (GST). The study group consisted of a total of 201 subjects which included nondiabetic healthy control subjects (n = 78) and diabetic patients (n = 123). Plasma total thiols, GST, copper and ceruloplasmin levels were measured all the subjects using spectrophotometric methods and FPG levels were determined in clinical chemistry analyzer Hitachi 912. There was significant increase in FPG (P<0.001) and copper (P<0.001) and decrease in ceruloplasmin (P<0.001) and protein thiols (P<0.001) in type 2 DM cases compared to healthy controls. There was no significant change in GST between type 2 DM cases and controls. There was significant negative correlation of FPG with antioxidants like ceruloplasmin (r = −0.420, P<0.001) and total thiols (r = −0.565, P<0.001). Protein thiols correlated positively with ceruloplasmin (r = 0.364, P<0.001). Our study indicates possible increase in copper mediated generation of ROS leading to increased consumption of available antioxidants in the body.     

Socio-Economic Profile of Shopkeepers in Embedded Markets: Social and Cultural Perspectives From a Hundred Years of Bengali Literary Works

Retailing, in the context of developing economies, has been claimed to be a social practice. A review of fictional literature from the ethno-linguistic region of Bengal may enhance our understanding of the social and cultural history of independent retailing. The evidence from social sciences shows that most retail markets in the economically less developed countries function in similar ways. Such a similarity in social structures may be explained using the concept of embeddedness. This article identifies the history of socio-economic roles of rural unorganised retailers in the embedded markets of developing economies through the discourse analysis of Bengali fictional literature.     

Academics’ perspectives of the teaching and development of generic employability skills in science curricula

ABSTRACT

Graduate employability is a key issue for higher education as new graduates face a highly competitive and rapidly changing employment sector. To maximise their likelihood of employment, graduates need to be able to demonstrate the skills and attributes most valued by employers. Employers, however, have long criticised the ability of graduates to contribute effectively to the workplace, especially due to a perceived lack of generic employability skills. This indicates a possible mismatch between the skills required by employers and those possessed by graduate applicants. This study addresses a gap in the scholarly literature regarding employability skills – the perspectives of science academics at an Australian and UK university regarding the promotion of generic employability skills in the subjects they teach. More specifically, this article discusses academics’ perspectives regarding: (a) which of the targeted generic skills were developed and assessed through their science units, and (b) the approaches used to promote the targeted skills and any associated challenges in employing those approaches. The discussion explores how shifting from traditional transmissive pedagogies to more problem-based approaches and embedding reflection into pedagogy and assessment practices would contribute to promoting the skills employers increasingly demand from science graduates.     

A geometric view of the mean of a set of numbers

The sample mean is sometimes depicted as a fulcrum placed under the Dot plot. We provide an alternative geometric visualization of the sample mean using the empirical cumulative distribution function or the cumulative histogram data.     

How Should We Measure Psychological Resilience in Sport Performers?

Psychological resilience is important in sport because athletes must constantly withstand a wide range of pressures to attain and sustain high performance. To advance psychologists’ understanding of this area, there exists an urgent need to develop a sport-specific measure of resilience. The purpose of this article is to review psychometric issues in resilience research and to discuss the implications for sport psychology. Drawing on the wider general psychology literature to inform the discussion, the narrative is divided into three main sections relating to resilience and its assessment: adversity, positive adaptation, and protective factors. The first section reviews the different ways that adversity has been measured and considers the potential problems of using items with varying degrees of controllability and risk. The second section discusses the different approaches to assessing positive adaptation and examines the issue of circularity pervasive in resilience research. The final section explores the various issues related to the assessment of protective factors drawing directly from current measures of resilience in other psychology sub-disciplines. The commentary concludes with key recommendations for sport psychology researchers seeking to develop a measure of psychological resilience in athletes.     

Wallace and natural selection, 1858

In the nineteenth century, Alfred Russel Wallace was generally acknowledged as one of the founders of evolutionary theory. But, during the twentieth century, his contributions came to be neglected as Darwin worship often replaced cogent historical assessment. This is a story worth studying. It shows how scientific advances are often simultaneously made by many different individuals working independently; these advances are as much products of their intellectual context as they are of individual genius or inspiration. The story also shows the power of social background and privilege within science (how Darwin managed to avoid being pre-empted by Wallace), how scientists compete for priority, and how future generations co-opt history to suit their own purposes.     

Hypogonadotropic Hypogonadism and Gynaecomastia in the Young Adult: A Case Series

We present three cases who presented to our Endocrinology OPD a few days apart with the common complaints of no or minimal development of secondary sexual characteristics. Although they had similar problems, investigations revealed a spectrum of different clinical, biochemical and genetic abnormalities. All the patients had otherwise normal anterior pituitary hormone secretion and sellar anatomy. One had a short Y chromosome, one was a Klinefelter syndrome and the other had no chromosomal abnormality. These findings along with absence of any detectable abnormality on pituitary imaging helped us diagnose these cases as Idiopathic hypogonadotropic hypogonadism. Treatment with testosterone showed marked improvement at 1 year follow up.