1,136 research outputs found

    Strain in wet thermally oxidized square and circular mesas

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    In this paper, we report the observation, through optical microscopy, of drumhead-like patterns in square and circular mesas which have been wet thermally oxidized to completion. Micro-Raman spectroscopy measurements are used to show that these patterns roughly correspond to variations in strain induced in surrounding semiconductor layers by the oxidation process. In addition, the patterns have a specific orientation with respect to the crystallographic axes of the semiconductor. A crystallographic dependence of the oxidation process itself is demonstrated and used to explain the orientation of the drumhead patterns

    Effect of cylindrical geometry on the wet thermal oxidation of AlAs

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    We have investigated the wet thermal oxidation of AlAs in cylindrical geometry, a typical configuration for vertical-cavity surface-emitting lasers. Through both experiment and theoretical calculations, we demonstrate a significantly different time dependence for circular mesas from what has been reported in the literature both in studies of stripes and in a study of circular mesas. We attribute this different time dependence to the effect of geometry on the oxidation

    Vegetable Forcing in Ohio

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    L'impacte dels mexicans en el creixement econòmic del Texas del sud, 1848-1930

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    Borderlands Research in Spanish, Mexican, and Texas Archives

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    Dr. Armando Alonzo will speak to UTRGV students in Dr. Jamie Starling’s HIST 6325: Seminar in Borderlands History course as well as students from HIST 3300, HIST 3333, and HIST 4399. Interested faculty are also invited to attend. Dr. Alonzo’s presentation will focus on researching the South Texas Borderlands in Spanish, Mexican, and Texas archives as well as the challenges of studying the region’s earlier Spanish colonial era and Native American history. A native of the Rio Grande Valley, Dr. Alonzo received his M.A. degree in history in 1983 from what was then the University of Texas – Pan American, where he wrote his thesis on “A History of the Mexicans in the Lower Rio Grande Valley of Texas: Their Role in Land Development and Commercial Agriculture, 1900-1930.” Dr. Alonzo earned a Ph.D. in History from Indiana University in 1991 with a dissertation that focused on “Tejano Rancheros and Changes in Land Tenure, Hidalgo County, Texas, 1850-1900.” His book, Tejano Legacy: Rancheros and Settlers in South Texas, 1734-1900 was published by University of New Mexico Press in 1998. The author of numerous peer-reviewed articles and scholarly conference presentations, Dr. Alonzo is currently researching a transnational history of Texas and Northern Mexico between 1700 and 1865.https://scholarworks.utrgv.edu/rdavidson/1010/thumbnail.jp

    Why Settle the Lands of the Seno Mexicano?

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    Natriuretic peptides and cardiovascular damage in the metabolic syndrome. Molecular mechanisms and clinical implications

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    Natriuretic peptides are endogenous antagonists of vasoconstrictor and salt- and water-retaining systems in the body's defence against blood pressure elevation and plasma volume expansion, through direct vasodilator, diuretic and natriuretic properties. In addition, natriuretic peptides may play a role in the modulation of the molecular mechanisms involved in metabolic regulation and cardiovascular remodelling. The metabolic syndrome is characterized by visceral obesity, hyperlipidaemia, vascular inflammation and hypertension, which are linked by peripheral insulin resistance. Increased visceral adiposity may contribute to the reduction in the circulating levels of natriuretic peptides. The dysregulation of neurohormonal systems, including the renin-angiotensin and the natriuretic peptide systems, may in turn contribute to the development of insulin resistance in dysmetabolic patients. In obese subjects with the metabolic syndrome, reduced levels of natriuretic peptides may be involved in the development of hypertension, vascular inflammation and cardio vascular remodelling, and this may predispose to the development of cardiovascular disease. The present review summarizes the regulation and function of the natriuretic peptide system in obese patients with the metabolic syndrome and the involvement of altered bioactive levels of natriuretic peptides in the pathophysiology of cardiovascular disease in patients with metabolic abnormalities

    All-Optical Reinforcement Learning in Solitonic X-Junctions

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    L'etologia ha dimostrato che gruppi di animali o colonie possono eseguire calcoli complessi distribuendo semplici processi decisionali ai membri del gruppo. Ad esempio, le colonie di formiche possono ottimizzare le traiettorie verso il cibo eseguendo sia un rinforzo (o una cancellazione) delle tracce di feromone sia spostarsi da una traiettoria ad un'altra con feromone piĂą forte. Questa procedura delle formiche possono essere implementati in un hardware fotonico per riprodurre l'elaborazione del segnale stigmergico. Presentiamo qui innovative giunzioni a X completamente integrate realizzate utilizzando guide d'onda solitoniche in grado di fornire entrambi i processi decisionali delle formiche. Le giunzioni a X proposte possono passare da comportamenti simmetrici (50/50) ad asimmetrici (80/20) utilizzando feedback ottici, cancellando i canali di uscita inutilizzati o rinforzando quelli usati.Ethology has shown that animal groups or colonies can perform complex calculation distributing simple decision-making processes to the group members. For example ant colonies can optimize the trajectories towards the food by performing both a reinforcement (or a cancellation) of the pheromone traces and a switch from one path to another with stronger pheromone. Such ant's processes can be implemented in a photonic hardware to reproduce stigmergic signal processing. We present innovative, completely integrated X-junctions realized using solitonic waveguides which can provide both ant's decision-making processes. The proposed X-junctions can switch from symmetric (50/50) to asymmetric behaviors (80/20) using optical feedbacks, vanishing unused output channels or reinforcing the used ones

    Do Employees From Less-Healthy Communities Use More Care and Cost More? Seeking to Establish a Business Case for Investment in Community Health.

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    INTRODUCTION: Few studies have examined the impact of community health on employers. We explored whether employed adults and their adult dependents living in less-healthy communities in the greater Philadelphia region used more care and incurred higher costs to employers than employees from healthier communities. METHODS: We used a multi-employer database to identify adult employees and dependents with continuous employment and mapped them to 31 zip code regions. We calculated community health scores at the regional level, by using metrics similar to the Robert Wood Johnson Foundation (RWJF) County Health Rankings but with local data. We used descriptive analyses and multilevel linear modeling to explore relationships between community health and 3 outcome variables: emergency department (ED) use, hospital use, and paid claims. Business leaders reviewed findings and offered insights on preparedness to invest in community health improvement. RESULTS: Poorer community health was associated with high use of ED services, after controlling for age and sex. After including a summary measure of racial composition at the zip code region level, the relationship between community health and ED use became nonsignificant. No significant relationships between community health and hospitalizations or paid claims were identified. Business leaders expressed interest in further understanding health needs of communities where their employees live. CONCLUSION: The health of communities in which adult employees and dependents live was associated with ED use, but similar relationships were not seen for hospitalizations or paid claims. This finding suggests a need for more primary care access. Despite limited quantitative evidence, business leaders expressed interest in guidance on investing in community health improvement
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