The spread of private tutoring in English in developing societies: exploring students’ perceptions     

M. Obaidul Hamid  Asaduzzaman Khan  M. Monjurul Islam 《Discourse: Studies in the Cultural Politics of Education》2018,39(6):868-886

ABSTRACT

Although research on private tutoring has gained visibility in recent years, private tutoring in English (PT-E) has not received notable attention. This paper examines students’ perceptions of PT-E in Bangladesh in terms of its necessity and helpfulness, peer pressure in PT-E participation and ethicality of PT-E practice and government intervention. Our analysis of survey data (N?=?572) leads to characterising PT-E and explaining the reasons for its popularity. As a popular learning space beyond formal schooling, PT-E is available in various forms and quality catering to the purchasing power of different social groups. We argue that students may resort to PT-E not because of its proven effectiveness but because of their declining faith in school English teaching. The paper contributes to our understanding of the complex interactions between the curricular (school) and non-curricular (PT-E) settings and family socioeconomic resources in the teaching of English as a globally desired language.  相似文献   

The Effects of Enrolling in Oversubscribed Prekindergarten Programs Through Third Grade     

Christina Weiland  Rebecca Unterman  Anna Shapiro  Sara Staszak  Shana Rochester  Eleanor Martin 《Child development》2020,91(5):1401-1422

This study leverages naturally occurring lotteries for oversubscribed Boston Public Schools prekindergarten program sites between 2007 and 2011, for 3,182 children (M = 4.5 years old) to estimate the impacts of winning a first choice lottery and enrolling in Boston prekindergarten versus losing a first choice lottery and not enrolling on children’s enrollment and persistence in district schools, grade retention, special education placement, and third-grade test scores. There are large effects on enrollment and persistence, but no effects on other examined outcomes for this subsample. Importantly, children who competed for oversubscribed seats were not representative of all appliers and almost all control-group children attended center-based preschool. Findings contribute to the larger evidence base and raise important considerations for future prekindergarten lottery-based studies.  相似文献   

The Designing Matrix: A Systemic Tool for Understanding the Visions and Images of New Educational Systems     

Badrul H. Khan 《Performance Improvement》1997,36(2):32-36

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Analysis and experimental investigation into a finite time current observer based adaptive backstepping control of buck converters     

Tousif Khan Nizami  Arghya Chakravarty  Chitralekha Mahanta 《Journal of The Franklin Institute》2018,355(12):4996-5017

In this paper, the issue of output voltage regulation in buck type dc-dc converters is addressed using a current sensorless control technique. The proposed strategy integrates a finite time current observer with an adaptive backstepping control scheme to yield a cost-effective and robust control mechanism. The overall controller stability in the sense of Lyapunov is proved. Applicability of the proposed control is verified experimentally on a buck converter in the laboratory. The control scheme is implemented on dSPACE DS1103 platform based on DSP TM320F240 processor. To examine the efficacy of the proposed method, the buck converter is subjected to a wide change in input voltage, load resistance and reference voltage. For comparison purpose, a conventional adaptive backstepping control scheme is evaluated under identical conditions of experimental study to examine the merit of the proposed control. The results obtained reveal that the proposed control is prompt in rejecting perturbations and achieves a smooth, reliable and satisfactory output voltage regulation with faithful and time bound estimation of inductor current. Thereby, this investigation demonstrates the validity of the proposed control in maintaining a stringent output voltage regulation in buck converters.  相似文献   

Probing the mechanical properties of brain cancer cells using a microfluidic cell squeezer device     

Z. S. Khan  S. A. Vanapalli 《Biomicrofluidics》2013,7(1)

Despite being invasive within surrounding brain tissues and the central nervous system, little is known about the mechanical properties of brain tumor cells in comparison with benign cells. Here, we present the first measurements of the peak pressure drop due to the passage of benign and cancerous brain cells through confined microchannels in a “microfluidic cell squeezer” device, as well as the elongation, speed, and entry time of the cells in confined channels. We find that cancerous and benign brain cells cannot be differentiated based on speeds or elongation. We have found that the entry time into a narrow constriction is a more sensitive indicator of the differences between malignant and healthy glial cells than pressure drops. Importantly, we also find that brain tumor cells take a longer time to squeeze through a constriction and migrate more slowly than benign cells in two dimensional wound healing assays. Based on these observations, we arrive at the surprising conclusion that the prevailing notion of extraneural cancer cells being more mechanically compliant than benign cells may not apply to brain cancer cells.  相似文献   

Hematological Parameters and RBC TBARS Level of Q 10 Supplemented Tribal Sickle Cell Patients: A Hospital Based Study     

A. S. Thakur  G. P. Littaru  S. Moesgaard  C. Dan sindberg  Y. Khan  C. M. Singh 《Indian journal of clinical biochemistry : IJCB》2013,28(2):185-188

The study has been undertaken as number of sickle cell patients in Chhattisgarh tribal population is 23.7 %. The Co enzyme Q10 is a strong antioxidant and energy producing compound. The patients were divided into three groups group A homozygous (SS), group B heterozygous (AS) and group C controls for TBARS study. The age group is 10–55 years and 200 mg of CoQ10 was given to A and B groups. The hematological parameters, C reactive protein as well as RBC TBARS level were performed by usual and standard techniques. The results were obtained as 25.37 % increased RBC level in group A and 23.24 % in group B. The increased hemoglobin level was observed as 16.73 % in group A and 10.7 % in group B. In case of WBC it was observed increased 24.38 % in group A and 12.0 % in group B. C-reactive protein was observed 7.8 times decreased in group A and 1.54 times in group B. The RBC TBARS level was also found decreased 48 % in group A and 51 % in group B as compared to group C. During the supplementation of coenzyme Q10 the pain caused by vaso-occlusive events has reduced. This significant increase in hematological parameters as well as decreased C-reactive protein and TBARS level suggest that the Q10 should be included in the diet of sickle cell patients.  相似文献   

A framework for web-based learning     

Badrul H. Khan 《TechTrends》2000,44(3):51-51

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Effects of audiotutorial and conventional instructional techniques on cognitive achievements     

Abdul G. Khan 《科学教学研究杂志》1980,17(1):47-53

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Glial cells: The other cells of the nervous system     

Yasmin Khan  Medha S. Rajadhyaksha 《Resonance》2002,7(6):6-13

Neuroscientists have believed for a long time that glial cells are supportive elements of the nervous system and have little role in neuronal function. Despite outnumbering neurons tenfold in the Central Nervous System (CNS), and contributing to more than half the brain volume, not much attention was paid to these cells. Recently, glial cells have been found to be far more active participants in CNS function. A set of glial cells, the oligodendrocytes, has attracted attention as their precursors have been found to be extremely plastic. Though these precursor cells are initially committed to form oligodendrocytes alone, they can also be induced to form astrocytes and neurons. Such examples of transdetermination are opening up new lines of research with immense clinical implications. In this part of the series we review some aspects of oligodendrocyte structure and function.  相似文献   

Gender and Education for All: Progress and problems in achieving gender equity     

Grace Chisamya  Joan DeJaeghere  Nancy Kendall  Marufa Aziz Khan 《International Journal of Educational Development》2012

The paper explores the effects of rapid increases in gender parity in primary schooling in Bangladesh and Malawi on gender inequities in schools and communities. Based on an analysis of comparative case studies of marginalized communities, we argue that educational initiatives focused on achieving gender parity provide limited evidence that girls’ educational experiences modeled significantly different gender norms than in communities, or that by being educated, girls experienced a transformation of the inequitable gender relations they faced in society. The data illustrate persistent gender discrimination related to educational attainment and learning, and gender-based violence in schools. These patterns of gendered discrimination and violence largely mirrored those that girls and boys experienced in their homes and communities, raising important questions about the transformational capacity of current gender parity and schooling models.  相似文献