Hydrogen refinement during solid phase epitaxy of buried amorphous silicon layers

The effect of hydrogen on the kinetics of solid phase epitaxy (SPE) have been studied in buried amorphous Si layers. The crystallization rate of the front amorphous/crystalline (a/c) interface is monitored with time resolved reflectivity.Secondary ion mass spectrometry(SIMS) is used to examine H implanted profiles at selected stages of the anneals. The H retardation of the SPE rate is determined up to a H concentration of 2.3×10²⁰ cm¯³ where the SPE rate decreases by 80%. Numerical simulations are performed to model the H diffusion, the moving a/c interfaces and the refinement of the H profile at these interfaces. Despite the high H concentration involved, a simple Fickian diffusion model results in good agreement with the SIMS data. The segregation coefficient is estimated to be 0.07 at 575 °C. A significant fraction of the H escapes from the a-Si layer during SPE especially once the two a/c interfaces meet which is signified by the lack of H-related voids after a subsequent high temperature anneal.This research was supported by a grant from the Australian Research Council

Christian affiliation, Christian practice, and attitudes to religious diversity : a quantitative analysis among 13- to 15-year-old female students in the UK

Within the context of the “Young People’s Attitudes to Religious Diversity” project at the Warwick Religions and Education Research Unit, this study examines the association between self-assigned Christian affiliation, self-reported Christian practice, and attitudes towards religious diversity among a sample of 5,748 13- to 15-year-old female students attending schools in England, Northern Ireland, Scotland, and Wales. The two hypotheses being tested are that, among female students, nominal Christians do not differ in their attitudes towards religious diversity from unaffiliated students and that church attendance leads to less tolerance of other religious groups. The data partly support the first hypothesis but not the second. Churchgoing Christian female students are more interested in and more tolerant of other religious groups. The data also draw attention to the perceived importance of religious education in schools for shaping views on religion and on religious diversity among unaffiliated students, nominal Christians, and practising Christians. Both the Christian churches and religious education in school seem to have an important part to play in nurturing a tolerant and inclusive religiously diverse society in the UK

Factors underpinning student perceptions of laboratory experiences

Background Survey data gathered as part of the Advancing Science by Enhancing Learning in the Laboratory (ASELL) project and its predecessors have been used previously to draw correlations between student perceptions of different aspects of laboratory-based activities and their perceived overall learning experience (Barrie, Bucat, Buntine, Burke da Silva, Crisp, George, Jamie, Kable, Lim, Pyke, Read, Sharma and Yeung, 2015). However, typical past analyses have involved the application of scoring techniques to ordered categorical response data, conflating student dependent and student independent contributions to student responses. Rasch modeling techniques provide an opportunity to control for the biases of individual students, revealing the more sample independent correlations in student perceptions which can be used to inform teaching practice. Particularly, the Linear Logistic Test Model (Fischer, 1995) is capable of expressing sample independent measures for each survey item as a linear combination of more basic factors of the experience. Aims The aim of this research was to derive a Linear Logistic Test Model for the ASELL Student Learning Experience (ASLE) survey, expressing “overall learning experience” as a linear combination of more basic factors of the learning experience. Methods A data set of 128,881 individual data points provided by over 9000 students in response to the ASLE survey, gathered from 29 practical activities run from 2011 to 2015 was input into a Rasch model, extracting student independent measures of quality for each experiment. These student independent measures were subjected to factor analysis, subsequently converting the results into a Linder Logistic Test Model of the ASLE survey data. Number of factors extracted was determined by balancing the parsimony of the model with the proportion of observed data variance explained, using the corrected Akaike Information Criterion (Burnham & Anderson, 2004). Results The final Linear Logistic Test Model reveals six major identifiable contributors to the laboratory learning experience. In descending order of impact on responses, these factors are the perceived connection to lecture theory, the quality of instructional material provided, understanding of theory through collaboration with others, the development of data interpretation skills, independent learning and the reliance on or appreciation for the demonstrator. A large component of “overall learning experience” appears to be due to aspects not addressed by ASLE survey items. The model yields equations for facets of the laboratory learning experience targeted by the ASLE survey, such as the equation for “overall learning experience” below (Equation 1). δ_(14 (overall learning experience)) = [■(-2@2@0@1@1@2@5)]⋅[■(〖 η〗_(theory focus)@〖 η〗_instructions@η_(collaborative understanding)@η_(data interpretation)@η_(independent learning)@η_demonstrators@η_(unexplained overall) )] (1) Similar equations are also obtained for other items of the survey, revealing models for fostering aspects of the experience such as student interest, increased understanding and development of technical skills. Conclusions Equations comprising the Linear logistic Test Model have a range of pedagogical implications for the structure of laboratory learning activities. Notably, increased understanding appears to be irrelevant to perceived “overall learning experience”, raising questions as to the consequential validity of using student response data to drive design of learning activities. A general theme of conflict between student preferences and attainment of learning objectives is recognized. References Barrie, S. C., R. B. Bucat, M. A. Buntine, K. Burke da Silva, G. T. Crisp, A. V. George, I. M. Jamie, S. H. Kable, K. F. Lim, S. M. Pyke, J. R. Read, M. D. Sharma & A. Yeung (2015). Development, Evaluation and Use of a Student Experience Survey in Undergraduate Science Laboratories: The Advancing Science by Enhancing Learning in the Laboratory Student Laboratory Learning Experience Survey. International Journal of Science Education, 37(11), 1795-1814. Burnham, K. P. & Anderson, D. R. (2004). Multimodel Inference: Understanding AIC and BIC in Model Selection. Sociological Methods & Research, 33(2), 261-304. Fischer, G. H. (1995). The linear logistic test model. Rasch models (pp. 131-155): Springer

Linear Estimation of Location and Scale Parameters Using Partial Maxima

Consider an i.i.d. sample X^*_1,X^*_2,...,X^*_n from a location-scale family, and assume that the only available observations consist of the partial maxima (or minima)sequence, X^*_{1:1},X^*_{2:2},...,X^*_{n:n}, where X^*_{j:j}=max{X^*_1,...,X^*_j}. This kind of truncation appears in several circumstances, including best performances in athletics events. In the case of partial maxima, the form of the BLUEs (best linear unbiased estimators) is quite similar to the form of the well-known Lloyd's (1952, Least-squares estimation of location and scale parameters using order statistics, Biometrika, vol. 39, pp. 88-95) BLUEs, based on (the sufficient sample of) order statistics, but, in contrast to the classical case, their consistency is no longer obvious. The present paper is mainly concerned with the scale parameter, showing that the variance of the partial maxima BLUE is at most of order O(1/log n), for a wide class of distributions.Comment: This article is devoted to the memory of my six-years-old, little daughter, Dionyssia, who leaved us on August 25, 2010, at Cephalonia isl. (26 pages, to appear in Metrika

The Impact of Rurality and Disadvantage on the Diagnostic Interval for Breast Cancer in a Large Population-Based Study of 3202 Women in Queensland, Australia.

Delays in diagnosing breast cancer (BC) can lead to poorer outcomes. We investigated factors related to the diagnostic interval in a population-based cohort of 3202 women diagnosed with BC in Queensland, Australia. Interviews ascertained method of detection and dates of medical/procedural appointments, and clinical information was obtained from medical records. Time intervals were calculated from self-recognition of symptoms (symptom-detected) or mammogram (screen-detected) to diagnosis (diagnostic interval (DI)). The cohort included 1560 women with symptom-detected and 1642 with screen-detected BC. Symptom-detected women had higher odds of DI of >60 days if they were Indigenous (OR = 3.12, 95% CI = 1.40, 6.98); lived in outer regional (OR = 1.50, 95% CI = 1.09, 2.06) or remote locations (OR = 2.46, 95% CI = 1.39, 4.38); or presented with a "non-lump" symptom (OR = 1.84, 95% CI = 1.43, 2.36). For screen-detected BC, women who were Indigenous (OR = 2.36, 95% CI = 1.03, 5.80); lived in remote locations (OR = 2.35, 95% CI = 1.24, 4.44); or disadvantaged areas (OR = 1.69, 95% CI = 1.17, 2.43) and attended a public screening facility (OR = 2.10, 95% CI = 1.40, 3.17) had higher odds of DI > 30 days. Our study indicates a disadvantage in terms of DI for rural, disadvantaged and Indigenous women. Difficulties in accessing primary care and diagnostic services are evident. There is a need to identify and implement an efficient and effective model of care to minimize avoidable longer diagnostic intervals

A prognostic survival model for women diagnosed with invasive breast cancer in Queensland, Australia.

PURPOSE: Prognostic models can help inform patients on the future course of their cancer and assist the decision making of clinicians and patients in respect to management and treatment of the cancer. In contrast to previous studies considering survival following treatment, this study aimed to develop a prognostic model to quantify breast cancer-specific survival at the time of diagnosis. METHODS: A large (n = 3323), population-based prospective cohort of women were diagnosed with invasive breast cancer in Queensland, Australia between 2010 and 2013, and followed up to December 2018. Data were collected through a validated semi-structured telephone interview and a self-administered questionnaire, along with data linkage to the Queensland Cancer Register and additional extraction from medical records. Flexible parametric survival models, with multiple imputation to deal with missing data, were used. RESULTS: Key factors identified as being predictive of poorer survival included more advanced stage at diagnosis, higher tumour grade, "triple negative" breast cancers, and being symptom-detected rather than screen detected. The Harrell's C-statistic for the final predictive model was 0.84 (95% CI 0.82, 0.87), while the area under the ROC curve for 5-year mortality was 0.87. The final model explained about 36% of the variation in survival, with stage at diagnosis alone explaining 26% of the variation. CONCLUSIONS: In addition to confirming the prognostic importance of stage, grade and clinical subtype, these results highlighted the independent survival benefit of breast cancers diagnosed through screening, although lead and length time bias should be considered. Understanding what additional factors contribute to the substantial unexplained variation in survival outcomes remains an important objective

The effects of central cholecystokinin receptor blockade on hypothalamic-pituitary-adrenal and symptomatic responses to overnight withdrawal from alprazolam

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142739/1/Abelson-Nesse-alprazolam-BioPsych-1995.pd

Novedades floristicas para el n de Marruecos

Se han seleccionado 29 novedades comarcales para el Catálogo de la flora del N de Marruecos, entre las especies recolectadas para el programa Semclimed en el país magrebí, durante la segunda parte de la campaña del mes de mayo de 2007. Estas campañas estaban orientadas a la recolección de semillas y la localización de poblaciones de especies raras y endémicas para el nuevo banco de germoplasma del Institut ScientiK que de la Universidad Mohamed V de Rabat, SEMCLIMED (Interreg IIIB Medocc-2005-05-4.1-E-110. Los recientes trabajos realizados en la catalogación de la flora del N de Marruecos permiten, a su vez, valorar el interés corológico de estas recolecciones

Monitoring temporal change in riparian vegetation of Great Basin National Park

Disturbance in riparian areas of semiarid ecosystems involves complex interactions of pulsed hydrologic flows, herbivory, fire, climatic effects, and anthropogenic influences. We resampled riparian vegetation within ten 10-m × 100-m plots that were initially sampled in 1992 in 4 watersheds of the Snake Range, east central Nevada. Our finding of significantly lower coverage of grasses, forbs, and shrubs within plots in 2001 compared with 1992 was not consistent with the management decision to remove livestock grazing from the watersheds in 1999. Change over time in cover of life-forms or bare ground was not predicted by scat counts within plots in 2001. Cover results were also not well explained by variability between the 2 sampling periods in either density of native herbivores or annual precipitation. In contrast, Engelmann spruce (Picea engelmannii) exhibited reduced abundance at all but the highest-elevation plot in which it occurred in 1992, and the magnitude of change in abundance was strongly predicted by plot elevation. Abundance of white fir (Abies concolor) individuals increased while aspen (Populus tremuloides) individuals decreased at 4 of 5 sites where they were sympatric, and changes in abundance in the 2 species were negatively correlated across those sites. Utility of monitoring data to detect change over time and contribute to adaptive management will vary with sample size, observer bias, use of repeatable or published methods, and precision of measurements, among other factors