Students' and teachers' perceptions of effective teaching and learning in the middle level science classroom: the effects on student achievement

The major purpose of the study was to examine the relationship between teacherstudent interpersonal behaviour in the middle level of schooling with the students' academic achievement in science as determined by the term grade (typically issued after a six or nine week grading period). The study also provided validation data for the Questionnaire on Teacher Interactions (QTI) survey instrument with a large American sample of students and teachers drawn from randomly selected the State of Ohio schools. The QTI was designed to elicit students' and teachers' perspectives of effective teaching and learning in classrooms. Numerous studies, here and abroad, during the last five years and have caused awareness that students' perceptions of their school experience are a significant influence on how and what students learn in the classroom. Few studies have been conducted on the topic of student perceptions in comparison to their respective teachers' perceptions in science or how this variance might influence student achievement. The focus of the present study was to compare the perceptions of students and their teachers regarding effective teaching and learning, while concurrently noting students' achievement in science. This study presumed that there was a definite disparity between what teachers perceive to be effective teaching and learning in comparison to what students perceive. The intention of the study was to identify some of the factors associated with any disparity. The hypothesis for the study, simply stated, was that student achievement, according to student's accumulative grade, would reflect a variance in perception with that of their science teacher.Restated, the student's perception of effective teaching and learning could demonstrate to be a strong indicator of academic success or failure, depending upon the extent of difference with their respective teachers'. The research design of the study was based on the survey research method incorporating: 1) student and teacher questionnaires; 2) student and teacher interviews and; 3) students' science achievement, as measured in a teacher-issued grade. A probability sample of 433 middle school students was surveyed using the 48-item short form of the Australian version of the QTI (Wubbels, 1993). This sample comprised 21 middle level science classes, ranging from grade 5 through grade 9. Twelve cooperating science teachers associated with the teaching of science to these students were also surveyed using Questionnaire on Teacher Interaction (QTI). In addition, random interviews were conducted using interview logs with 6 teachers and 6 students selected from a convenience sample of those also responding to the questionnaire. Another major component of the research design was the term grade recorded by the cooperating science teacher, as a means of gauging "student academic achievement". All student and teacher questionnaire data were statistically analysed using Microsoft Excel 2000 and the Statistical Package for Social Science (SPSS) for Windows 1999. The analysis was according to the proper categories in the QTI based on leadership, helpful/friendly, understanding, student responsibility and freedom, uncertain, and dissatisfied, admonishing and strict behaviour established in the QTI.The use of both qualitative and quantitative data collection methods from a range of data sources provided a means of triangulation to strengthen the validity of the findings, which thus afforded a means of comparing data consistency and cross validation for the purpose of improving the rigour of the research design. As a means of collecting empirical data, schools were randomly chosen (probability sample) from the 20001-2002 Ohio Educational Directory, a directory produced by the Ohio Department of Education. Thirty-three schools were drawn. Between October 20002 and January 2003, each school was sent two letters inviting their participation in the study; one letter was sent to the on-site principal and one to the "head science teacher". Five weeks from the date the original letter was sent out to those not responding. Eventually, twenty-one classes returned their surveys for analysis. The Questionnaire of Teacher Interaction (QTI) was chosen due to its record of validity and its ease of administering. The qualitative data were tallied and recorded. The quantitative data analysis was completed using both manual and computerised methods to address the objectives of this study

Testing of Milliwatt Power Source Components

A milliwatt power source (MPS) has been developed to satisfy the requirements of several potential solar system exploration missions. The MPS is a small power source consisting of three major components: a space qualified heat source (RHU), a thermopile (thermoelectric converter or TEC) and a container to direct the RHU heat to the TEC. Thermopiles from Hi-Z Technology, Inc. of San Diego and the Institute of Thermoelectricity of Chernivtsi Ukraine suitable for the MPS were tested and shown to perform as expected, producing 40 mW of power with a temperature difference of about 170°C. Such thermopiles were successfully life tested for up to a year. A MPS container designed and built by Swales Aerospace was tested with both a TEC simulator and actual TEC. The Swales unit, tested under dynamic vacuum, provided less temperature difference than anticipated, such that the TEC produced 20 mW of power with heat input equivalent to a RHU

The anatomical and functional benefit of bevacizumab in the treatment of macular edema associated with Purtscher-like retinopathy

We read the article by Miguel et al1 regarding Purtscher’s and Purtscher-like retinopathies with great interest. As the authors well describe, ‘Purtscher-like retinopathy’ is diagnosed in patients with fundus findings similar to Purtscher’s retinopathy, without a history of trauma but with known systemic associations.1 Current proposed mechanisms for the underlying pathogenesis include leukocyte aggregation by activated complement factor 5 (C5a).2 As noted by the authors’ systematic review, there is currently no established treatment for Purtscher-like retinopathy, although the literature consists of several case reports of treatment with corticosteroids, without certainty as to effect on the clinical course.1 Herein, we report for the first time a case of Purtscher-like retinopathy treated successfully with intravitreal bevacizumab injection

An efficient data Parallelization of the Radix-23 (Carbon) FFT on GPU/CPU

Solving Complex Problem that is coupled with intensive workloads; necessities the access to a massively parallel computational power. Up to date, Graphic Processing Units (GPUs) are the only architecture that could handle the most complex computationally intensive workloads. In the light of this rapid-growing advancement in computational technologies, this paper will propose a high-performance parallel radix-23 FFT suitable for such GPU and CPU systems. The proposed algorithm could reduce the computational complexity by a factor that tends to reach pr if implemented in parallel (pr is the number of cores/threads) plus the combination phase to complete the required FFT

International multi-center study of iatrogenic retinal tears in pars plana vitrectomy

AIM: To study and compare the effect of different surgical settings on the development of iatrogenic retinal tears (IRT) in conventional (20-gauge) and microincisional vitrectomy. METHODS: An international retrospective comparative study of 394 patients who had simple vitrectomy at three tertiary centers. Surgeries were performed by four retina surgeons using different viewing systems. Two groups of eyes were compared: microincisional vitrectomy (327 eyes) and conventional (67 eyes) vitrectomy. An iatrogenic tear was defined as the occurrence of one or more peripheral retinal tears during surgery or at any visit in the first 6wk postoperatively. RESULTS: Mean age was 67+/-12y and 55% were female. Iatrogenic tears occurred in 11/394 (2.8%) of eyes. The rate of tears was similar among different surgeons and viewing systems (P=0.93 and P=0.76, respectively). Surgical indication, preexisting pseudophakia/aphakia, induction of posterior vitreous detachment (PVD) during surgery, and the use triamcinolone acetonide didn\u27t significantly affect the rate of tears (P \u3e 0.1 for all factors). A higher rate of tears was found in the conventional group compared to the microincisional group (respectively, 7.5%, 1.8%, P=0.02). CONCLUSION: The rate of IRT in vitrectomy is not significantly affected by surgical indication, preexisting PVD or pseudophakia, or use of triamcinolone or different viewing systems but is significantly higher in conventional vitrectomy. Microincisional platforms improve the safety of vitrectomy regardless of the viewing system used

Divisia Second Moments: An Application of Stochastic Index Number Theory

W. A. Barnett originated the Divisia monetary aggregates, using Diewert's results on superlative index numbers and Barnett's derivation of the user cost of monetary asset services. The resulting Divisia index can be interpreted as a first moment aggregating over growth rates with expenditure shares serving as probabilities. But Theil showed that there are analogous higher order Divisia moments providing distributional information. In this paper we use the Divisia second moments to investigate distributional information in the monetary aggregate growth rates and to measure aggregation error in the Divisia first moments

Divisia Second Moments

W. A. Barnett originated the Divisia monetary aggregates, using Diewert's results on superlative index numbers and Barnett's derivation of the user cost of monetary asset services. The resulting Divisia index can be interpreted as a first moment aggregating over growth rates with expenditure shares serving as probabilities. But Theil showed that there are analogous higher order Divisia moments providing distributional information. In this paper we use the Divisia second moments to investigate distributional information in the monetary aggregate growth rates

Divisia Second Moments: An Application of Stochastic Index Number Theory

W. A. Barnett originated the Divisia monetary aggregates, using Diewert's results on superlative index numbers and Barnett's derivation of the user cost of monetary asset services. The resulting Divisia index can be interpreted as a first moment aggregating over growth rates with expenditure shares serving as probabilities. But Theil showed that there are analogous higher order Divisia moments providing distributional information. In this paper we use the Divisia second moments to investigate distributional information in the monetary aggregate growth rates and to measure aggregation error in the Divisia first moments

Miniaturized Radioisotope Solid State Power Sources

Abstract. Electrical power requirements for the next generation of deep space missions cover a wide range from the kilowatt to the milliwatt. Several of these missions call for the development of compact, low weight, long life, rugged power sources capable of delivering a few milliwatts up to a couple of watts while operating in harsh environments. Advanced solid state thermoelectric microdevices combined with radioisotope heat sources and energy storage devices such as capacitors are ideally suited for these applications. By making use of macroscopic film technology, microgenerators operating across relatively small temperature differences can be conceptualized for a variety of high heat flux or low heat flux heat source configurations. Moreover, by shrinking the size of the thermoelements and increasing their number to several thousands in a single structure, these devices can generate high voltages even at low power outputs that are more compatible with electronic components. Because the miniaturization of state-of-the-art thermoelectric module technology based on Bi 2 Te 3 alloys is limited due to mechanical and manufacturing constraints, we are developing novel microdevices using integrated-circuit type fabrication processes, electrochemical deposition techniques and high thermal conductivity substrate materials. One power source concept is based on several thermoelectric microgenerator modules that are tightly integrated with a 1.1W Radioisotope Heater Unit. Such a system could deliver up to 50mW of electrical power in a small lightweight package of approximately 50 to 60g and 30cm 3 . An even higher degree of miniaturization and high specific power values (mW/mm 3 ) can be obtained when considering the potential use of radioisotope materials for an alpha-voltaic or a hybrid thermoelectric/alpha-voltaic power source. Some of the technical challenges associated with these concepts are discussed in this paper