Pulse-width-modulated speed control of d.c. motors

This paper deals with the analytical and experimental investigations of an open-loop pulse-width-modulated d.c. motor speed control system. The analysis is carried out by two different approaches, circuit approach and the lattice function approach. From the circuit approach, the relationship between the current-ripple-factor and the pulse width is obtained. The lattice function approach yields the relationship between pulse width and the speed variation. There is good correlation between the experimental and theoretical results.     

Circadian Rhythm of Serum Cortisol in Female Patients with Fibromyalgia Syndrome

Fibromyalgia syndrome (FMS) patients have disturbed sleep patterns which may lead to altered circadian rhythm in serum cortisol secretion. The aim of this study was to assess circadian changes, if any, in serum cortisol levels in female patients with FMS. Cortisol levels were estimated every 6 h during 24 h period; in 40 female patients satisfying ACR criteria for FMS (Age 36.4 ± 9.9), and 40 healthy females without FMS (Age 33.8 ± 11.1). A significant difference in the night time serum cortisol level was observed among the patients and control groups (patients, 12.9 ± 9.7 controls 5.8 ± 3.0; p < 0.01). However, no significant difference was found in serum cortisol levels in patients and control groups in the morning (patients, 28.4 ± 13.2 controls, 27.6 ± 14.5; p > 0.05), afternoon (patients, 14.4 ± 5.6 controls, 14.0 ± 6.6; p > 0.05) and evening hours (patients, 10.9 ± 5.8 controls, 8.9 ± 3.6; p > 0.05). It could be concluded that there is an abnormality in circadian secretion of cortisol in female FMS patients.     

A tribute to ‘unsung teachers’: teachers’ influences on students enrolling in STEM programs with the intent of entering STEM careers

This narrative inquiry examines teachers’ influences on undergraduate and graduate students who enrolled in STEM programs and intended to enter STEM careers. Three National Science Foundation (NSF) scholarship grants sat in the backdrop. Narrative exemplars were crafted using the interpretative tools of broadening, burrowing, storying and restorying, fictionalisation and serial interpretation. Three diverse students’ narratives constituted the science education cases: one from teacher education, another arising from cyber technology and a third involving cyber security. The influence of the university students’ former teachers cohered around five themes: 1) same program-different narratives, 2) in loco parentis, 3) counter stories, 4) learning in small moments, and 5) the importance of the liberal arts in STEM education. The students’ narratives form instructive models for their siblings and other students pursuing STEM degrees and careers. Most importantly, the multiperspectival stories of experiences capture the far-reaching impact of ‘unsung teachers’ whose long-term influence is greatly underestimated by the public.     

Role of bilirubin, vitamin C and ceruloplasmin as antioxidants in coronary artery disease [CAD]

A study has been carried out on 250 CAD patients to see how the serum levels of three antioxidants i.e., Vitamin C, Bilirubin and Ceruloplasmin are related to the CAD risk factors and characteristics in these patients. The number of severe category CAD patients declined by 7–18% with increasing serum levels of the three antioxidants and, triple vessel disease declined by 14–20%. A decline of 39% in Myocardial Infarction (MI) occurred with increasing serum Ceruloplasmin. Serum Ceruloplasmin was significantly lower in the MI group compared to the non MI group CAD patients. There was a steady and a significant decline in the mean values of serum levels of cholesterol, Triglyceride, VLDL cholesterol along with BMI with increasing serum level. The study indicates that with increasing serum levels of the three antioxidants studied, the % MI along with % Triple vessel disease and severity of CAD goes down suggesting that the modifiable risk factors have to be suitably modified in order to maintain a reasonably high level of these antioxidants, as the risk factors are inversely related to the serum antioxidant levels.     

Negotiating meanings of gender justice: Critical reflections on dialogs and debates in a non-governmental organization (NGO)

In this paper, we reflect upon how dialogs and debates in a non-governmental organization (NGO) – CARE India in the context of a girls’ education project shaped staff members’ understandings of gender justice. As CARE India staff shared their experiences in the field, in the organization, and in domestic spaces during gender training sessions and other forums, their different politics in these spaces shaped how they translated global discourses of gender justice to produce fluid, contested, and contextual understandings. While these dialogs included the voices of diverse social actors in identifying the capabilities needed for gender justice in education, they were often reframed by local NGO actors.     

Effects of the COVID-19 pandemic on caregiver mental health and the child caregiving environment in a low-resource,rural context

Early child development has been influenced directly and indirectly by the COVID-19 pandemic, and these effects are exacerbated in contexts of poverty. This study estimates effects of the pandemic and subsequent population lockdowns on mental health, caregiving practices, and freedom of movement among female caregivers of children 6–27 months (50% female), in rural Bangladesh. A cohort (N = 517) was assessed before and during the pandemic (May–June, 2019 and July–September, 2020). Caregivers who experienced more food insecurity and financial loss during the pandemic reported larger increases in depressive symptoms (0.26 SD, 95% CI 0.08–0.44; 0.21 SD, 0.04–0.40) compared to less affected caregivers. Stimulating caregiving and freedom of movement results were inconsistent. Increases in depressive symptoms during the pandemic may have consequences for child development.