Design and simulation of strained-Si/strained-SiGe dual channel hetero-structure MOSFETs

With a unified physics-based model linking MOSFET performance to carrier mobility and drive current, it is shown that nearly continuous carrier mobility increase has been achieved by introduction of process-induced and global-induced strain, which has been responsible for increase in device performance commensurately with scaling. Strained silicon-germanium technology is a hot research area, explored by many different research groups for present and future CMOS technology, due to its high hole mobility and easy process integration with silicon. Several heterostructure architectures for strained Si/SiGe have been shown in the literature. A dual channel heterostructure consisting of strained Si/Si1-xGex on a relaxed SiGe buffer provides a platform for fabricating MOS transistors with high drive currents, resulting from high carrier mobility and carrier velocity, due to presence of compressively strained silicon germanium layer. This works reports the design, modeling and simulation of NMOS and PMOS transistors with a tensile strained Si channel layer and compressively strained SiGe channel layer for a 65 nm logic technology node. Since most of the recent work on development of strained Si/SiGe has been experimental in nature, developments of compact models are necessary to predict the device behavior. A unified modeling approach consisting of different physics-based models has been formulated in this work and their ability to predict the device behavior has been investigated. In addition to this, quantum mechanical simulations were performed in order to investigate and model the device behavior. High p/n-channel drive currents of 0.43 and 0.98 mA/Gm, respectively, are reported in this work. However with improved performance, ~ 10% electrostatic degradation was observed in PMOS due to buried channel device

Childhood obesity and socio-economic class

Background: Childhood obesity has reached epidemic levels in developed countries. Overweight and obesity in childhood are known to have significant impact on both physical and psychological health. The mechanism of obesity development is not fully understood and it is believed to be a disorder with multiple causes. There are supporting evidence that excessive sugar intake by soft drink, increased portion size and steady decline in physical activity have been playing major role in the rising rates of obesity all around the world. The aim of this study was to compare the obesity status of children (5-18 years) from the upper and middle socio-economic class.Methods: 400 children (200 boys and 200 girls) in the age group of 5-18 years from upper and middle socio-economic status (According to the modified version of Kuppuswamy’s socio-economic status scale) were selected as subjects for this study. Weight and height were measured in minimum acceptable standard clothing without shoes and socks and BMI was calculated. Because there are changes in body weight and height with age, BMI levels among children and teens need to be expressed relative to other children of the same age and sex. Number of children in each BMI-for-age-percentile-range were calculated. By using chi–square test an association of overweight/obesity with socio-economic class was studied in children.Results: The prevalence of overweight/obesity was more in upper socio-economic class boys in comparison with middle socio-economic class boys, more girls from upper socio-economic class were overweight/obese in comparison with middle socio-economic class girls and more girls were obese in comparison to boys from upper socio-economic class.Conclusions: The primary prevention could be the key plan for controlling the current epidemic of obesity and these strategies seem to be more effective in children than in adults

Management of sobbing tot in a pediatric dental office: A review

The most common way by which child expresses fear and anxiety is by crying at dental office. Proper knowledge and understanding are required to deliver effective dental treatment to a child by the application of various behavioral management techniques. Treating a crying child is one of the most demanding and tiring situations encountered in dentistry. Behavior management in a crying child is a continuum interaction with the child, directed toward communication and education in an endeavor, to allay anxiety and fear and to promote understanding of good oral health and the process by which it is achieved. This article was aimed to review the various reasons for stimulation of cry of the child in the dental office and behavior techniques employed by the dentist for proper management of the child

Perceptions of Medical Students on Research Curriculum: A Cross-sectional Study

Introduction: Medical colleges promote research by incorporating it into the curriculum, which enables students to acknowledge it as a career prospect. The aim of the study was to assess the perceptions of medical students on research curriculum. Methods: This cross-sectional study was conducted among 544 medical students (interns and post-graduates) at AIIMS Rishikesh in 2020. Data was collected thorough online self-administered questionnaire. A comparison between groups was made using the Mann-Whitney test or chi-square test p < 0.05 was considered statistically significant. Results: Out of 544 participants, 218 (40.1%) responded with complete data. The total median score for the self-perceived ability of study participants regarding performing the research tasks differed significantly between interns and post-graduates [29.5 (24.0–34.2) vs 33 (25.2–39.7), p = 0.03]. They suggested that mandatory research projects, workshops, and training should be included in the curriculum. Conclusion: Feedback from medical students regarding the need for guided research projects, hands-on training, and inclusion of research methodology as a course in UG curriculum and provision of support in the form of incentives, academic credits, and motivation are well noted and guide the resource faculties to modify their teaching and student support programs

Predicting the impact of climate change on range and genetic diversity patterns of the endangered endemic Nilgiri tahr (Nilgiritragus hylocrius) in the western Ghats, India

[Context] Climate change is considered an important factor affecting the distribution and genetic diversity of species. While many studies have described the influence of climate change on population structure at various scales, little is known about the genetic consequences of a changing climate on endemic species.[Objectives] To assess possible changes in the distribution and genetic structure of the endangered Nilgiri tahr (Nilgiritragus hylocrius), which is endemic to the Western Ghats in India, under climate change and human disturbances.[Methods] We integrated tahr occurrence and nuclear DNA data with environmental geo-datasets to project the response of tahr populations to future climate change with respect to its distribution, genetic diversity and population structure. We screened the environmental variables using MaxEnt to identify a manageable set of predictors to be used in an ensemble approach, based on ten species distribution modelling techniques, to quantify the current tahr distribution. We then projected the distribution and genetic structure under two climate change scenarios.[Results] We found that suitable habitat for tahr (9,605 km2) is determined predominantly by a combination of climatic, human disturbance and topographic factors that result in a highly fragmented habitat throughout its distribution range in the Western Ghats. Under the severe high emissions RCP8.5 scenario tahr populations may lose more than half of their available habitat (55.5%) by 2070. Application of spatial Bayesian clustering suggests that their current genetic structure comprise four genetic clusters, with three of them reflecting a clear geographic structure. However, under climate change, two of these clusters may be lost, and in the future a homogenization of the genetic background of the remaining populations may arise due to prevalence of one gene pool cluster in the remaining populations.[Conclusions] Our interdisciplinary approach that combines niche modelling and genetic data identified the climate refugia (i.e., the remaining stable habitats that overlap with the current suitable areas), where the tahr populations would be restricted to small, isolated and fragmented areas. Essential factors to avert local extinctions of vulnerable tahr populations are a reduction of human disturbances, dispersal of tahr between fragmented populations, and the availability of corridors.This research was supported by the Department of Biotechnology, Ministry of Science and Technology, Government of India, and by a German Research Foundation (DFG) fellowship awarded to RK (project number 273837911).Peer reviewe

Tigers of Sundarbans in India: Is the Population a Separate Conservation Unit?

The Sundarbans tiger inhabits a unique mangrove habitat and are morphologically distinct from the recognized tiger subspecies in terms of skull morphometrics and body size. Thus, there is an urgent need to assess their ecological and genetic distinctiveness and determine if Sundarbans tigers should be defined and managed as separate conservation unit. We utilized nine microsatellites and 3 kb from four mitochondrial DNA (mtDNA) genes to estimate genetic variability, population structure, demographic parameters and visualize historic and contemporary connectivity among tiger populations from Sundarbans and mainland India. We also evaluated the traits that determine exchangeability or adaptive differences among tiger populations. Data from both markers suggest that Sundarbans tiger is not a separate tiger subspecies and should be regarded as Bengal tiger (P. t. tigris) subspecies. Maximum likelihood phylogenetic analyses of the mtDNA data revealed reciprocal monophyly. Genetic differentiation was found stronger for mtDNA than nuclear DNA. Microsatellite markers indicated low genetic variation in Sundarbans tigers (He= 0.58) as compared to other mainland populations, such as northern and Peninsular (Hebetween 0.67- 0.70). Molecular data supports migration between mainland and Sundarbans populations until very recent times. We attribute this reduction in gene flow to accelerated fragmentation and habitat alteration in the landscape over the past few centuries. Demographic analyses suggest that Sundarbans tigers have diverged recently from peninsular tiger population within last 2000 years. Sundarbans tigers are the most divergent group of Bengal tigers, and ecologically non-exchangeable with other tiger populations, and thus should be managed as a separate "evolutionarily significant unit" (ESU) following the adaptive evolutionary conservation (AEC) concept.Wildlife Institute of India, Dehra Dun (India)

Electrophotographic-model-based halftoning and analysis of clustered-dot halftoning with direct binary search

Most halftoning algorithms assume there is no interaction between neighboring dots or if there is, it is additive. Without accounting for dot-gain effect, the printed image will not have the appearance predicted by the halftoning algorithm. Thus, there is need to embed a printer model in the halftoning algorithm which can predict such deviations and develop a halftone accordingly. The direct binary search (DBS) algorithm employs a search heuristic to minimize the mean squared perceptually filtered error between the halftone and continuous-tone original images. We incorporate a measurement-based stochastic model for dot interactions of an electro-photographic printer within the iterative DBS binary halftoning algorithm. The stochastic model developed is based on microscopic absorptance and variance measurements. We present an efficient strategy to estimate the impact of 5×5 neighborhood pixels on the central pixel absorptance. By including the impact of 5×5 neighborhood pixels, the average relative error between the predicted tone and tone observed is reduced from around 23% to 4%. Also, the experimental results show that electro-photography-model based halftoning reduces the mottle and banding artifacts. We also embed our printer model in stochastic clustered-dot halftoning algorithm CLU-DBS. The method CLU-DBS uses different filters in the initialization and update phases, in comparison to the same filters used in both the phases in the conventional DBS method. In this work, we derive a closed form expression for cost metric that is minimized in the CLU-DBS framework. This cost metric analysis not only provides us in-depth understanding of stochastic clustered-dot halftoning but also simplifies and speeds up the screen design algorithm and it also enables us to embed our printer model to generate visually pleasing stochastic clustered-dot textures