Four- and five-layer silicon-clad dielectric waveguides

Computer modeling studies conducted on four-layer silicon-clad dielectric waveguides indicate that the attenuation (alpha) and mode index (beta/K) behave as exponentially damped sinusoids as the silicon thickness is increased. The observed effect can be explained quite simply as a periodic coupling between the guided modes of the lossless structure and the lossy modes supported by the high-refractive index silicon. The attenuation and mode index are significantly altered by conductivity changes in the silicon; an amplitude modulator and an intensity modulator were proposed using these results. Predicted high attenuations in the device may be reduced significantly with a silicon dioxide buffer layer between the semiconductor and the polystyrene guide. Experimental confirmation of the predicted characteristics is still necessary. A number of thin-silicon film waveguides have been RF sputtered but attenuation measurements to verify the damped oscillatory behavior are forthcoming. Conductivity variations of the silicon should demonstrate the modulation capabilities

Investigation of semiconductor clad optical waveguides

The properties of semiconductor-clad optical waveguides based on glass substrates were investigated. Computer modeling studies on four-layer silicon-clad planar dielectric waveguides indicated that the attenuation and mode index should behave as exponentially damped sinusoids as the silicon thickness is decreased below one micrometer. This effect can be explained as a periodic coupling between the guided modes of the lossless structure and the lossy modes supported by the high refractive index silicon. The computer studies also show that both the attenuation and mode index of the propagating mode are significantly altered by conductivity charges in the silicon. Silicon claddings were RF sputtered onto AgNO3-NaNO3 ion exchanged waveguides and preliminary measurements of attenuation were made. An expression was developed which predicts the attenuation of the silicon clad waveguide from the attenuation and phase characteristics of a silicon waveguide. Several applications of these clad waveguides are suggested and methods for increasing the photo response of the RF sputtered silicon films are described

Where Is the CommUNITY? A Qualitative Case Study of a School Closure in an Urban School District

Family and community engagement are a proven strategy for strengthening schools. Across the United States, parents and community members have pressed school boards and district leadership for more transparency and broader participation in decisions about school turnaround. The purpose of this qualitative case study is to understand the decision-making process for the school closure of Rocky Mountain High School, a neighborhood school in an Urban School District in the Rocky Mountain West and the impact it had on the community. To better understand this dilemma, a case study method was used to identify real-life perspectives of community members associated with school closures and their beliefs of how their community has been affected socially, emotionally, and financially by the closing of a neighborhood school. Because school closures happen more often in neighborhoods where the majority of residents are people of color, a critical race perspective was cross referenced to examine school closures as a matter of space in educational reforms. The findings to the central research question for this study: How do school closings affect lower socioeconomic urban communities in which they serve? yielded five themes: (a) The Community believed a singular focus on data (standardized test scores) was used to justify the school closure; (b) The Community believed historical racialized methods were used to establish the Pebbles community and ultimately used to close Rocky Mountain High School; (c) The Community believed money, power, and influence dictated the outcome; (d) The Community believed the process was manufactured; and (e) The Community did not believe their voice mattered in the process. The collected data highlighted how a particular school closure was decided, how the decision was reached, and the outcomes of the decision. In addition, the overview of the process revealed community perceptions that believe their voice was limited in scope

Investigation of direct integrated optics modulators

Direct optical modulation techniques applicable to integrated optical data preprocessors were studied. Emphasis was placed on the analysis and fabrication of a field effect type modulator. A series of computer modeling studies were performed to determine the effects of semiconductor cladding on the fields of propagating waves in planar dielectric waveguides. These studies predicted that changes in the propagation characteristics of waveguides clad with silicon and gallium arsenide could be made large enough to be useful in modulators. These effects are dependent on the complex permittivity and thickness of the cladding. Since the conductivity of the cladding can be changed by the photon generation of hole-electron pairs, incoherent light may be used as the input to modulate a coherent light beam. Waveguides were fabricated and silicon claddings were applied to verify the theoretical predictions

Investigation of semiconductor clad optical waveguides

Glass waveguides are studied because of the ease and economy of fabricating devices in glass. All calculations are based on the assumption of a glass guide and substrate, but the effects being studied will occur on other materials if the proper refractive indices are used in the calculations

A Comparative Study Teaching Chemistry Using the 5E Learning Cycle and Traditional Teaching with a Large English Language Learner Population in a Middle School Setting

For decades science educators and educational institutions have been concerned with the status of science content being taught in K-12 schools and the delivery of the content. Thus, educational reformers in the United States continue to strive to solve the problem on how to best teach science for optimal success in learning. The constructivist movement has been at the forefront of this effort. With mandatory testing nationwide and an increase in science, technology, engineering, and mathematics (STEM) jobs with little workforce to fulfill these needs, the question of what to teach and how to teach science remains a concern among educators and all stakeholders. The purpose of this research was to determine if students’ chemistry knowledge and interest can be increased by using the 5E learning cycle in a middle school with a high population of English language learners. The participants were eighth-grade middle school students in a large metropolitan area. Students participated in a month-long chemistry unit. The study was a quantitative, quasi-experimental design with a control group using a traditional lecture-style teaching strategy and an experimental group using the 5E learning cycle. Students completed a pre-and post-student attitude in science surveys, a pretest/posttest for each mini-unit taught, and completed daily exit tickets using the Expert Science Teaching Educational Evaluation Model (ESTEEM) instrument to measure daily student outcomes in main idea, student inquiry, and relevancy. Analysis of the data showed that there was no statistical difference between the two groups overall, and all students experienced a gain in content knowledge overall. All students demonstrated a statistically significant difference in their interest in science class, activities in science class, and outside of school. Data also showed that scores in writing the main idea and writing inquiry questions about the content increased over time

Mivacurium Sensitivity at the Adductor Pollicis and Hand Grip Muscles: Differences Between Males and Females

Background: Males lose more handgrip strength (HGS) than females when adductor pollicis (AP) TOF ratio decreases. The reason is unclear. Objectives: The primary aim of this study was to explore gender-related differences in neuromuscular sensitivity to mivacurium. As a secondary aim, clearance of mivacurium was determined. Methods: In 10 healthy males and 10 healthy females, constant-rate infusions of mivacurium were administered to obtain three different levels of stable neuromuscular block (normalized acceleromyography AP TOF ratio 80, 60, and 40%) in each study subject. Arterial blood samples were collected to determine mivacurium plasma concentrations. The HGS was measured every five minutes. A Hill equation was fitted to data on mivacurium concentration versus normalized AP TOF ratio and HGS to determine drug concentrations associated with 50% maximum effect (C50 AP TOF ratio and C50 HGS). Differences within and between genders were tested with the parametric t-test. Clearance of mivacurium was calculated at each block level as the ratio between drug infusion  rate and concentration. Gender-related differences in relationships between AP TOF ratio and HGS, mivacurium infusion rates, and mivacurium plasma concentrations were determined with linear mixed-models. Results: The C50 AP TOF ratio was significantly greater than C50HGSin males, yet not in females. Mivacurium infusion rates, needed to maintain stable neuromuscular blocks, were significantly greater in males, while clearance was similar between genders. Males lost significantly more HGS with decreasing AP TOF ratio than females, both in absolute (kg) and relative (percentage of baseline) terms. Conclusions: In males, yet not in females, the AP was significantly less sensitive to the effect of mivacurium than the muscles involved in the handgrip function. Thisfindingexplainswhyhandgripstrength decreasesmorein males than females with decreasing AP TOF ratio during the mivacurium block

Parental Expectations and Prosocial Behavior of Adolescents From Low-Income Backgrounds: A Cross-Cultural Comparison Between Three Countries¿Argentina, Colombia, and Spain

Parental expectations are influenced by cultural models, which in turn are subject to a great influence from historically fluctuating features of the socioeconomic background. Parental expectations seem to be linked to children¿s social and emotional development in terms of empathy and prosocial behavior. The current study aims to (a) compare low-income adolescents¿ perceptions of parental expectations of prosocial and antisocial behavior across three Latin countries (Argentina, Colombia, and Spain), (b) compare the empathy and prosocial behavior between the three countries, (c) compare the prosocial behavior between the three countries, and (d) study the effect of perceived parental expectations and empathy on the prosocial behavior of adolescents in all three of the countries studied in this research. The sample was made up of 446 Argentinean adolescents, 474 Colombian adolescents, and 632 Spanish adolescents. The Expected Parental Reactions Scale, Interpersonal Reactivity Index, and Prosocial Behavior Questionnaire were used to measure the variables included in this study. Results reveal considerable differences between children¿s perceptions of parental expectations in different countries. Results also show the existence of significant differences between male and female adolescents. In all three countries, girls score more highly than boys in prosocial behavior and empathy. Furthermore, we find that low-income Argentinean adolescents score more highly than Spanish and Colombian adolescents in prosocial behavior measures. Finally, expected parental reactions toward prosocial behavior and empathy seem to have an influence on the adolescents¿ development of prosocial behavior in all three countries

Response of variable impedance stripline to pulse excitation

We describe a simple method to predict the transient response of variable impedance stripline to pulse excitation. The method uses a finite difference based, quasi-static impedance formulation to calculate the reflection coefficient at each point along the direction of pulse propagation and the subsequent short pulse behavior of a variable impedance structure. A Fortran computer program is written to determine the quasi-static impedance. Excellent agreement of better than 1% between the finite difference impedance predictions and experimental results is noted. A second computer program is written utilizing previous results but essentially incorporating reflection and transmission from several discontinuities to analyze the transient response of the structure. This transient analysis yields good agreement between predictions and results obtained by means of time domain reflectometry

DIVISION II COLLEGE BASKETBALL ATTENDANCE: WHY MEN’S OVER WOMEN’S?

The survey reflects how attendance at Angelo State University Men’s Basketball games differed from attendance at Angelo State University Women’s Basketball games for the past season.The survey reflects how attendance at Angelo State University Men’s Basketball games differed from attendance at Angelo State University Women’s Basketball games for the past season. This survey included various factors used to determine why more individuals chose to attend the Men’s Basketball games than the Women’s. These factors include: (a) Interest level in game (b) Game intensity level (c) Cost of tickets (d) Time of day/week game is held (e) Involvement/connection with the entire team/individual player/coach(es) and (f) Persuasion from family/peers The results of the survey demonstrate the major factors and the most influential factors as to why individuals, mainly ages 18 years to over 70 years, chose to attend more Angelo State University Men’s Basketball games than Women’s