Improving the perceptual quality of ideal binary masked speech

It is known that applying a time-frequency binary mask to very noisy speech can improve its intelligibility but results in poor perceptual quality. In this paper we propose a new approach to applying a binary mask that combines the intelligibility gains of conventional binary masking with the perceptual quality gains of a classical speech enhancer. The binary mask is not applied directly as a time-frequency gain as in most previous studies. Instead, the mask is used to supply prior information to a classical speech enhancer about the probability of speech presence in different time-frequency regions. Using an oracle ideal binary mask, we show that the proposed method results in a higher predicted quality than other methods of applying a binary mask whilst preserving the improvements in predicted intelligibility

Effectiveness of student response systems in terms of learning environment, attitudes and achievement

In order to investigate the effectiveness of using Student Response Systems (SRS) among grade 7 and 8 science students in New York, the How Do You Feel About This Class? (HDYFATC) questionnaire was administered to 1097 students (532 students did use SRS and 565 students who did not use SRS). Data analyses attested to the sound factorial validity and internal consistency reliability of the HDYFATC, as well as its ability to differentiate between the perceptions of students in different classrooms. Very large differences between users and non-users of SRS, ranging from 1.17 to 2.45 standard deviations for various learning environment scales, attitudes and achievement, supported the efficacy of using SRS

Neonatal cerebrovascular autoregulation.

Cerebrovascular pressure autoregulation is the physiologic mechanism that holds cerebral blood flow (CBF) relatively constant across changes in cerebral perfusion pressure (CPP). Cerebral vasoreactivity refers to the vasoconstriction and vasodilation that occur during fluctuations in arterial blood pressure (ABP) to maintain autoregulation. These are vital protective mechanisms of the brain. Impairments in pressure autoregulation increase the risk of brain injury and persistent neurologic disability. Autoregulation may be impaired during various neonatal disease states including prematurity, hypoxic-ischemic encephalopathy (HIE), intraventricular hemorrhage, congenital cardiac disease, and infants requiring extracorporeal membrane oxygenation (ECMO). Because infants are exquisitely sensitive to changes in cerebral blood flow (CBF), both hypoperfusion and hyperperfusion can cause significant neurologic injury. We will review neonatal pressure autoregulation and autoregulation monitoring techniques with a focus on brain protection. Current clinical therapies have failed to fully prevent permanent brain injuries in neonates. Adjuvant treatments that support and optimize autoregulation may improve neurologic outcomes

Evaluation of anthropometry activities for high school science: student outcomes and classroom environment

The study involved the evaluation of anthropometric activities for high school science. The activities actively engaged students in the process of gathering, processing and analyzing data derived from human body measurements, with students using their prior knowledge acquired in science, mathematics and computer classes to interpret this information. Quantitative (survey) and qualitative (interview) methods were used to provide answers to the research questions. The quantitative portion of the study involved students' achievement, students' attitudes to science and students' perceptions of the classroom learning environment. A pretest/posttest design was used with achievement outcomes, however, only a single assessment of student attitudes and classroom environment was made. The sample size used to gather data on students' attitudes to science and students' perceptions of the leaming environment was 726 students. Five hundred and ninety-eight (598) students tools the biology test. However, analyses were restricted to the subsample of 158 students who had experienced the anthropometric laboratory activity. Twenty-four students (24) were interviewed for the qualitative part of the study. Data generated from the interviews were used to complement information provided in the surveys. The main purpose of this research was to evaluate these student-centered activities in terms of students' achievement, students' attitudes and students' perceptions of the science classroom environment. Other aims included: to validate generally-applicable measures of classroom learning environments and students' attitudes to science; to investigate gender differences in students' achievement, attitudes and perceptions of classroom environment; and to investigate associations between the classroom learning environment and the student outcomes of performance and attitudes.Some of the important findings of this study included: 1. In reference to the survey instruments, the item analyses supported the internal consistency reliability and ability to differentiate between classrooms of the learning environment questionnaire and the analyses of attitude data supported the factorial validity, internal consistency reliability and discriminant validity of the attitude questionnaire. 2. Substantial differences between the pretest and posttest scores for the achievement measures in Biology and anthropometric activities were found. These findings were supported by statistically significant t-test scores and effect sizes. 3. There was a positive influence of using anthropometric activities on both students' attitudes and their perceptions of the classroom learning environment. The findings based on qualitative information (interviews, which involved twenty-four students) were consistent with patterns emerging from our quantitative information (surveys, which involved 760 students) and they supported the effectiveness of the anthropometric activities. 4. The analysis of gender differences in students' achievement, attitudes and perceptions of classroom environment revealed that boys have more positive attitudes to science than girls do and is in agreement with past studies. However, females' students demonstrated more favorable perceptions of the learning environment than mates, primarily with Student Cohesiveness and Rule Clarity. 5. The association between student attitudes and their perception of the leaming environment indicated that students' attitudes to science are most likely to be positive in laboratory classes where student perceive a strong integration between the concepts and principles covered in theory classes and in laboratory classes. These findings are consistent with results in other countries.6. The association between achievement and student perceptions of their learning environment, suggest that integration of theoretical concepts with laboratory activities (Integration), a cohesive student group (Student Cohesiveness) and using appropriate laboratory materials and equipment (Material Environment) are likely to lead to student achievement. This finding replicates the results of previous studies. 7. I found stronger outcome-environment associations for attitudes than for achievement. This finding is consistent with results from past research. The contributions and significance of this study can be summarized as follows: 1. One of the key components of this study was the development and implementation of the innovative anthropometric laboratory activity, which was especially designed for this research. 2. Another contribution of this study is to the field of integrated curriculum instruction. While most instructional curricular activities are subject specific, this study is interdisciplinary in nature because it effectively links concepts and skills from science, mathematics, statistics, and technology (graphing calculators and computers). 3. A unique feature of this research is that it had an evaluation component involving student performance, student attitudes, and the nature of the classroom learning environment. Therefore, the study contributes to the field of learning environment research by adding another study to the limited research that has employed the classroom environment as a criterion of effectiveness in evaluating educational innovations. The study has the potential to help other science teachers to apply these ideas in their classrooms