Strain-induced modifications of the band structure of InxGa1-xP–In0.5Al0.5P multiple quantum wells

Includes bibliographical references.The effect of strain on the band structure of InxGa1-xP-In0.5Al0.5P multiple quantum wells (MQW's) has been investigated from high-pressure and low-temperature photoluminescence measurements. The biaxial strain in the wells was varied between +0.6% compressive to -0.85% tensile strain by changing the well composition x from 0.57 to 0.37. Strain increases the valence band offsets in either tensile or compressively strained structures. Whereas relatively insensitive to tensile strain, the valence band offsets showed a strong dependence on the magnitude of the compressive strain. Good agreement is found between the measured valence band offsets and those predicted by the model solid theory, except for the largest compressively strained MQW's, for which the model calculations underestimate the measured valence band offset. Strain and the associated variations in composition also modified the separation among the well states associated with Γ1c, L1c, and X1c. From these results, the bandgaps of each conduction band extrema were calculated in InxGa1-xP for 0.37 < x < 0.57 and compared with the predictions of the model solid theory.This work was supported by the National Science Foundation under Grant DMR 9321422 and Grant ECS-9502888, and by the AFOSR under Contract F49620-93-1-0021

Contributing to accurate high pressure viscosity measurements: Vibrating wire viscometer and falling body viscometer techniques

Producción CientíficaTwo new techniques for measuring viscosities at high pressure have been implemented at the TERMOCAL laboratory in order to obtain accurate values of thermophysical properties such as viscosity, especially at high pressures. A vibrating-wire viscometer has been developed to accurately measure viscosities over the working ranges T = (283.15 to 423.15) K and p = (0.1 to 140) MPa. The setup of the equipment includes calibration with toluene and its validation with n-dodecane. A falling body viscometer able to measure viscosities at T = (253.15 to 523.15) K and p = (0.1 to 140) MPa is also presented in this work. Results of calibration with toluene and its verification with n-heptane and n-dodecane are reported. The detailed uncertainty budgets for both techniques are included in this work. Moreover, the paper studies the compatibility of the results obtained using both techniques according to their corresponding uncertainties in order to obtain reliable data. New viscosity measurements of 1,2,4-trimethylbenzene and 2,2,4-trimethylpentane have been performed and included in the paper.2017-12-29Ministerio de Educación (Spanish Government) for his FPU scholarship for doctoral studiesConsejería de Educación de la JCyL for project VA295U1

The newcastle 85+ study

Funding Information: Funding: The Newcastle 85+ study was jointly funded by the Medical Research Council and Biotechnology and Biomedical Science Research Council (G0500997), now part of UK Research and Innovation (UKRI) in addition to the Newcastle Healthcare Charity. The following waves were funded by the Dunhill Medical Trust (R124/0509), Newcastle University, UK Medical Research Council and the British Heart Foundation. Overall, the project was supported by National Institute for Health Research Newcastle Biomedical Research Centre based at Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University. This particular analysis (vitamin D and telomere length) received no additional external funding. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.(1) Introduction: vitamin D may maintain the telomere length, either directly or via the inflammation effect and/or modulating the rate of cell proliferation. Whilst results from crosssectional studies investigating the association between 25(OH)D concentration and telomere length have been mixed, there is a dearth of data from prospective studies which have assessed these associations. This study aimed to examine the association between 25(OH)D concentration in plasma and telomere length in blood cells in very-old adults (≥85 years old) at baseline, 18 months and 36 months by controlling for related lifestyle factors. (2) Methodology: our prospective cohort study comprised 775 participants from the Newcastle 85+ Study who had 25(OH)D measurements at baseline. Plasma 25(OH)D was stratified as 50 nmol/L (high). Peripheral blood mononuclear cell telomere length was measured by quantitative real-time polymerase chain reaction at baseline, 18 and 36 months from baseline. (3) Results: a positive significant association was found between 25(OH)D concentration and telomere length amongst very-old participants at baseline (95% CI = 12.0–110.3, B = 61.2 ± 5.0, p = 0.015). This association was negative at 18 months (95% CI = −59.9–−7.5, B = −33.7 ± 13.3, p = 0.012) but was non-significant at 36 months. (4) Conclusion: Circulating 25(OH)D concentration shows inconsistent relationships with telomere length over time in very-old (85+ year old) adults.publishersversionpublishe

Effect of indirect Γ-L and Γ-X transfer on the carrier dynamics of InGaP/InAlP multiple quantum wells

Includes bibliographical references (page 104).Indirect Γ-L scattering within the well, and real space carrier transfer to the barrier X1c states are shown to significantly affect the carrier dynamics in In0.48Ga0.52P/In0.5Al0.5P multiple quantum wells. When carriers transfer to the indirect states occurs, the carrier dynamics is modified by the slow return of the carriers from the low mobility states to the well. As a result, the absorption recovery time increases by almost an order of magnitude. Carrier transfer to the indirect states also increases the carrier lifetime to values characteristic of indirect recombination.This work is supported by the National Science Foundation through Grant Nos. DMR 9321422, ECS-9502888, EEC-9015128, the Colorado Advanced Technology Institute, Grant No. 0594.75.0738, and by AFOSR contract F49620-93-1-0021

Advancing the Entry-Level Practitioner: A Curricular Model of the Professional Occupational Therapy Doctoral Degree

The recent growth of entry-level occupational therapy doctoral (EL-OTD) programs has been met with mixed opinions from both occupational therapy educators and practitioners. These opinions occasionally have been accompanied by uncertainty about the specific curricular components that differentiate the EL-OTD from the entry-level master’s degree. In an effort to address this uncertainty, the purpose of this article is to present one example of an EL-OTD curricular model and describe its distinct educational components. This curricular model integrates recommendations for doctoral education originally proposed by Case-Smith et al. (2014) and is characterized by the following three components: 1) Advanced Coursework; 2) the Doctoral Capstone Project; and 3) the Doctoral Capstone Experience. We share the lessons learned after matriculating three cohorts of EL-OTD students and describe influences from the field of implementation science that have informed the development of our curriculum

Factores sociodemográficos y adecuación de la atención prenatal asociada a la mortalidad perinatal en gestantes colombianas

el adecuado seguimiento clínico y el cumplimiento de los requerimientos nutricionales, son aspectos esenciales para el adecuado desarrollo fetal y la culminación exitosa del embarazo. El objetivo de este estudio fue determinar la asociación entre los factores sociodemográficos y el seguimiento prenatal asociados a la mortalidad perinatal en gestantes de Colombia.An adequate monitoring and the compliance of the nutritional requirements are essential for fetal development and successful control of pregnancy outcomes. This study aimed to determine the association between sociodemographic factors and the pre-birth monitoring associated with

Picosecond absorption dynamics of photoexcited InGaP epitaxial films

Includes bibliographical references (page 92).The absorption recovery of a photoexcited InGaP epitaxial film 0.4 µm thick was investigated using the pump-probe laser technique and found to have a time constant of 55 ps at room temperature. Measurements done in the temperature range of 300-50 K show the decay of the photoexcited carrier distribution to be dominated by ambipolar diffusion and surface recombination. The measured absorption recovery time constant corresponds to an ambipolar diffusion coefficient D > 2.8 cm2/s and a surface recombination velocity of S > 4 × 105 cm/s at room temperature.This work was supported by the National Science Foundation grant (USA/Argentina) INT 8802563, the Air Force Office of Scientific Research (contract 89-0513), and the Center for Optoelectronic Computing Systems, sponsored by the National Science Foundation/Engineering Research Center grant ECD 9015128 and by the Colorado Advanced Technology Institute, an agency of the State of Colorado. C. S. Menoni acknowledges the support of the National Science Foundation grant ECS 9008899 and the CSU Faculty Research Grant

L1 transfer in the acquisition of manner and path in Spanish by native speakers of English

In this article the authors argue that L1 transfer from English is not only important in the early stages of L2 acquisition of Spanish, but remains influential in later stages if there is not enough positive evidence for the learners to progress in their development (Lefebvre, White, & Jourdan, 2006). The findings are based on analyses of path and manner of movement in stories told by British students of Spanish (N = 68) of three different proficiency levels. Verbs that conflate motion and path, on the one hand, are mastered early, possibly because the existence of Latinate path verbs, such as enter and ascend in English, facilitate their early acquisition by British learners of Spanish. Contrary to the findings of Cadierno (2004) and Cadierno and Ruiz (2006), the encoding of manner, in particular in boundary crossing contexts, seems to pose enormous difficulties, even among students who had been abroad on a placement in a Spanish-speaking country prior to the data collection. An analysis of the frequency of manner verbs in Spanish corpora shows that one of the key reasons why students struggle with manner is that manner verbs are so infrequent in Spanish. The authors claim that scarce positive evidence in the language exposed to and little or no negative evidence are responsible for the long-lasting effect of transfer on the expression of manner

Construction of the secondary care administrative records frailty (SCARF) index and validation on older women with operable invasive breast cancer in England and Wales:a cohort study

OBJECTIVES: Studies that use national datasets to evaluate the management of older women with breast cancer are often constrained by a lack of information on patient fitness. This study constructed a frailty index for use with secondary care administrative records and evaluated its ability to improve models of treatment patterns and overall survival in women with breast cancer. DESIGN: Retrospective cohort study. PARTICIPANTS: Women aged ≥50 years with oestrogen receptor (ER) positive early invasive breast cancer diagnosed between 2014 and 2017 in England. METHODS: The secondary care administrative records frailty (SCARF) index was based on the cumulative deficit model of frailty, using International Statistical Classification of Diseases, Injuries and Causes of Death, 10th revision codes to define a set of deficits. The index was applied to administrative records that were linked to national cancer registry datasets. The ability of the SCARF index to improve the performance of regression models to explain observed variation in the rate of surgery and overall survival was evaluated using Harrell's c-statistic and decision curve analysis. External validation was performed on a dataset of similar women diagnosed in Wales. RESULTS: The SCARF index captured 32 deficits that cover functional impairment, geriatric syndromes, problems with nutrition, cognition and mood, and medical comorbidities. In the English dataset (n=67 925), the prevalence of frailty in women aged 50-69, 70-79 and ≥80 years was 15%, 28% and 47%, respectively. Adding a frailty measure to regression models containing age, tumour characteristics and comorbidity improved their ability to: (1) discriminate between whether a woman was likely to have surgery and (2) predict overall survival. Similar results were obtained when the models were applied to the Welsh cohort (n=4 230). CONCLUSION: The SCARF index provides a simple and consistent method to identify frailty in population level data and could help describe differences in breast cancer treatments and outcomes