Compilation of Class Size Findings: Grade Level, School, and District.

ERIC Educational Resources Information Center

Miller-Whitehead, Marie

This study provides an overview of class size research, examples of various class size and pupil-teacher-ratio (PTR) configurations commonly used by practitioners, and the most recent findings of scientifically controlled experimental Tennessee STAR studies. The learning environment is hierarchical in nature, with student-level data influenced by…

An Examination of Teachers' Perceptions and Practice when Teaching Large and Reduced-Size Classes: Do Teachers Really Teach Them in the Same Way?

ERIC Educational Resources Information Center

Harfitt, Gary James

2012-01-01

Class size research suggests that teachers do not vary their teaching strategies when moving from large to smaller classes. This study draws on interviews and classroom observations of three experienced English language teachers working with large and reduced-size classes in Hong Kong secondary schools. Findings from the study point to subtle…

Focus on California's Class-Size Reduction: Smaller Classes Aim To Launch Early Literacy.

ERIC Educational Resources Information Center

McRobbie, Joan

Smaller class sizes in California were viewed as a way to improve K-3 education, especially in the area of literacy. The urgency to act prompted state leaders to adopt class-size reduction (CSR) without knowing for sure that it would work and without establishing a formal procedure for evaluating the program. This report looks at past research on…

Another Look at the Glass and Smith Study on Class Size

ERIC Educational Resources Information Center

Phelps, James L.

2011-01-01

One of the most influential studies affecting educational policy is Glass and Smith's 1978 study, "Meta-Analysis of Research on the Relationship of Class-Size and Achievement." Since its publication, educational policymakers have referenced it frequently as the justification for reducing class size. While teachers and the public had long believed…

Class Size and Academic Achievement in Introductory Political Science Courses

ERIC Educational Resources Information Center

Towner, Terri L.

2016-01-01

Research on the influence of class size on student academic achievement is important for university instructors, administrators, and students. The article examines the influence of class size--a small section versus a large section--in introductory political science courses on student grades in two comparable semesters. It is expected that…

Class Size Revisited: Glass and Smith in Perspective.

ERIC Educational Resources Information Center

Hess, Fritz

Gene V. Glass and Mary Lee Smith claim in their report, "Meta-Analysis of Research on the Relationship of Class-Size and Achievement" (ED 168 129), that their integration of data from 80 previous studies through complex regression analysis techniques revealed a "clear and strong relationship" between decreases in class size and increases in…

How Class Size Makes a Difference. Research & Development.

ERIC Educational Resources Information Center

Egelson, Paula; Harman, Patrick; Hood, Art; Achilles, C. M.

Landmark studies in the late 1970s and 1980s, including Tennessee's Project STAR (Student Teacher Achievement Ratio), raised the nation's awareness that reduced class size does have a positive impact on students' academic achievement. This report provides a sketch of class-size reduction's history in a prefatory overview. Chapter 1 describes…

Effects of Class Size and Attendance Policy on University Classroom Interaction in Taiwan

ERIC Educational Resources Information Center

Bai, Yin; Chang, Te-Sheng

2016-01-01

Classroom interaction experience is one of the main parts of students' learning lives. However, surprisingly little research has investigated students' perceptions of classroom interaction with different attendance policies across different class sizes in the higher education system. To elucidate the effects of class size and attendance policy on…

The Opportunity Cost of Smaller Classes: A State-By-State Spending Analysis. Schools in Crisis: Making Ends Meet

ERIC Educational Resources Information Center

Roza, Marguerite; Ouijdani, Monica

2012-01-01

Two seemingly different threads are in play on the issue of class size. The first is manifested in media reports that tell readers that class sizes are rising to concerning levels. The second thread appears in the work of some researchers and education leaders and suggests that repurposing class-size reduction funds to pay for other reforms may…

What We Have Learned about Class Size Reduction in California. Capstone Report.

ERIC Educational Resources Information Center

Bohrnstedt, George W., Ed.; Stecher, Brian M., Ed.

This final report on the California Class Size Reduction (CSR) initiative summarizes findings from three earlier reports dating back to 1997. Chapter 1 recaps the history of California's CSR initiative and includes a discussion of what state leaders' expectations were when CSR was passed. The chapter also describes research on class-size reduction…

Class Size Effects on Reading Achievement Using PIRLS Data: Evidence from Greece

ERIC Educational Resources Information Center

Konstantopoulos, Spyros; Traynor, Anne

2014-01-01

Background/Context: The effects of class size on student achievement have gained considerable attention in education research and policy, especially over the last 30 years. Perhaps the best evidence about the effects of class size thus far has been produced from analyses of Project STAR data, a large-scale experiment where students and teachers…

The Effects of Class Size on Student Achievement in Intermediate Level Elementary Students

ERIC Educational Resources Information Center

McInerney, Melissa

2014-01-01

Class size and student achievement have been debated for decades. The vast amount of research on this topic is either conflicting or inconclusive. There are large and small scale studies that support both sides of this dilemma (Achilles, Nye, Boyd-Zaharias, Fulton, & Cain, 1994; Glass & Smith, 1979; Slavin, 1989). Class size reduction is a…

What the Research Tells Us: Class Size Reduction. Information Capsule. Volume 1001

ERIC Educational Resources Information Center

Romanik, Dale

2010-01-01

This Information Capsule examines the background and history in addition to research findings pertaining to class size reduction (CSR). This Capsule concludes that although educational researchers have not definitively agreed upon the effectiveness of CSR, given its almost universal public appeal, there is little doubt it is here to stay in some…

The Class Size Question: A Study at Different Levels of Analysis. ACER Research Monograph No. 26.

ERIC Educational Resources Information Center

Larkin, Anthony I.; Keeves, John P.

The purpose of this investigation was to examine the ways in which class size affected other facets of the educational environment of the classroom. The study focused on the commonly found positive relationship between class size and achievement. The most plausible explanation of the evidence seems to involve the effects of grouping more able…

Class Size Reduction and Urban Students. ERIC Digest.

ERIC Educational Resources Information Center

Schwartz, Wendy

Researchers have long investigated whether smaller classes improve student achievement. Their conclusions suggest that class size reduction (CSR) can result in greater in-depth coverage of subject matter by teachers, enhanced learning and stronger engagement by students, more personalized teacher-student relationships, and safer schools with fewer…

Making Class Size Work in the Middle Grades

ERIC Educational Resources Information Center

Tienken, C. H.; Achilles, C. M.

2006-01-01

Most research on the positive effects of class-size reduction (CSR) has occurred in the elementary level (Word, Johnston, Bain, Fulton, Zaharias, Lintz, Achilles, Folger, & Breda, 1990; Molnar, Smith, Zahorik, Palmer, Halbach, & Ehrle, 1999). Is CSR an important variable in improving education in the middle grades? Can small classes be…

The Non-Cognitive Returns to Class Size

ERIC Educational Resources Information Center

Dee, Thomas S.; West, Martin R.

2011-01-01

The authors use nationally representative survey data and a research design that relies on contemporaneous within-student and within-teacher comparisons across two academic subjects to estimate how class size affects certain non-cognitive skills in middle school. Their results indicate that smaller eighth-grade classes are associated with…

Class Size: Teachers' Perspectives

ERIC Educational Resources Information Center

Watson, Kevin; Handal, Boris; Maher, Marguerite

2016-01-01

A consistent body of research shows that large classes have been perceived by teachers as an obstacle to deliver quality teaching. This large-scale study sought to investigate further those differential effects by asking 1,119 teachers from 321 K-12 schools in New South Wales (Australia) their perceptions of ideal class size for a variety of…

The Effects of Instructor Participation and Class Size on Student Participation in an Online Class Discussion Forum

ERIC Educational Resources Information Center

Parks-Stamm, Elizabeth J.; Zafonte, Maria; Palenque, Stephanie M.

2017-01-01

Student participation in online discussion forums is associated with positive outcomes for student achievement and satisfaction, but research findings on the impact of class size and instructors' participation on student participation have been mixed. The present study analyzed the frequency of instructor and student posts in asynchronous…

Three Essays on the Economics of Education: Class-Size Reduction, Teacher Labor Markets, and Teacher Effectiveness

ERIC Educational Resources Information Center

Dieterle, Steven

2012-01-01

Prior research has established the potential for achievement gains from attending smaller classes. However, large statewide class-size reduction (CSR) policies have not been found to consistently realize such gains. A leading explanation for the disappointing performance of CSR policies is that schools are forced to hire additional teachers of…

Class Size: Can School Districts Capitalize on the Benefits of Smaller Classes?

ERIC Educational Resources Information Center

Hertling, Elizabeth; Leonard, Courtney; Lumsden, Linda; Smith, Stuart C.

2000-01-01

This report is intended to help policymakers understand the benefits of class-size reduction (CSR). It assesses the costs of CSR, considers some research-based alternatives, and explores strategies that will help educators realize the benefits of CSR when it is implemented. It examines how CSR enhances student achievement, such as when the…

Experimental Estimates of the Impacts of Class Size on Test Scores: Robustness and Heterogeneity

ERIC Educational Resources Information Center

Ding, Weili; Lehrer, Steven F.

2011-01-01

Proponents of class size reductions (CSRs) draw heavily on the results from Project Student/Teacher Achievement Ratio to support their initiatives. Adding to the political appeal of these initiative are reports that minority and economically disadvantaged students received the largest benefits from smaller classes. We extend this research in two…

Social class and family size as determinants of attributed machismo, femininity, and family planning: a field study in two South American communities.

PubMed

Nicassio, P M

1977-12-01

A study was conducted to determine the way in which stereotypes of machismo and femininity are associated with family size and perceptions of family planning. A total of 144 adults, male and female, from a lower class and an upper middle class urban area in Colombia were asked to respond to photographs of Colombian families varying in size and state of completeness. The study illustrated the critical role of sex-role identity and sex-role organization as variables having an effect on fertility. The lower-class respondents described parents in the photographs as significantly more macho or feminine because of their children than the upper-middle-class subjects did. Future research should attempt to measure when this drive to sex-role identity is strongest, i.e., when men and women are most driven to reproduce in order to "prove" themselves. Both lower- and upper-middle-class male groups considered male dominance in marriage to be directly linked with family size. Perceptions of the use of family planning decreased linearly with family size for both social groups, although the lower-class females attributed more family planning to spouses of large families than upper-middle-class females. It is suggested that further research deal with the ways in which constructs of machismo and male dominance vary between the sexes and among socioeconomic groups and the ways in which they impact on fertility.

Class-Size Reduction: Using What's Been Learned To Inform Educational Decisions. The Informed Educator Series.

ERIC Educational Resources Information Center

Boniface, Russell; Protheroe, Nancy

Class-size reduction (CSR) has been a complex and contentious issue for the last quarter century. Although the small-class concept was adopted because it appealed to common sense, research over time has revealed a mix of confounding variables, instead of a definitive conclusion. Some CSR efforts, such as Tennessee's Project STAR and Wisconsin's…

Capitalizing on Small Class Size. ERIC Digest Number 136.

ERIC Educational Resources Information Center

O'Connell, Jessica; Smith, Stuart C.

This Digest examines school districts' efforts to reap the greatest benefit from smaller classes. Although the report discusses teaching strategies that are most effective in small classes, research has shown that teachers do not significantly change their teaching practices when they move from larger to smaller classes. Smaller classes mean…

Small is Beautiful When...

ERIC Educational Resources Information Center

Dixon, Annabelle

1980-01-01

The author, Deputy Head of Chalk Dell Infant School in Hertford, England, reviews research on the effects of class size and analyzes her own experience with a class of 33 and a class of 23 students. (Editor/SJL)

Financing Class Size Reduction

ERIC Educational Resources Information Center

Achilles, C. M.

2005-01-01

Class size reduction has been shown to, among other things, improve academic achievement for all students and particularly for low-income and minority students. With the No Child Left Behind Act's heavy emphasis on scientifically based research, adequate yearly progress, and disaggregated results, one wonders why all children aren't enrolled in…

What Have Researchers Learned from Project STAR?

ERIC Educational Resources Information Center

Schanzenbach, Diane Whitmore

2007-01-01

Project STAR (Student/Teacher Achievement Ratio) was a large-scale randomized trial of reduced class sizes in kindergarten through the third grade. Because of the scope of the experiment, it has been used in many policy discussions. For example, the California statewide class-size-reduction policy was justified, in part, by the successes of…

Class Size Reduction in a Large Urban School District: A Mixed Methodology Evaluation Research Study.

ERIC Educational Resources Information Center

Munoz, Marco A.

This study evaluated the Class Size Reduction (CSR) program in 34 elementary schools in Kentucky's Jefferson County Public Schools. The CSR program is a federal initiative to help elementary schools improve student learning by hiring additional teachers. Qualitative data were collected using unstructured interviews, site observations, and document…

Reducing Class Size: What Do We Know?

ERIC Educational Resources Information Center

Bascia, Nina

2010-01-01

This report provides an overview of findings from the research on primary class size reduction as a strategy to improve student learning. Its purpose is to provide a comprehensive and balanced picture of a very popular educational reform strategy that has often been seen as a "quick fix" for improving students' opportunities to learn in…

The Effects of Class Size on Students' Academic Achievement

ERIC Educational Resources Information Center

Wilson, Claire

2011-01-01

The purpose of this quantitative correlational research was to study the relationship between class size and students' academic achievement. Citywide language arts and math test scores for third and fifth grade students in four New York City public schools were examined using a variety of variables including (a) gender, (b) ethnicity, (c) grade…

Relationship of Class-Size to Classroom Processes, Teacher Satisfaction and Pupil Affect: A Meta-Analysis.

ERIC Educational Resources Information Center

Smith, Mary Lee; Glass, Gene V.

Using data from previously completed research, the authors of this report attempted to examine the relationship between class size and measures of outcomes such as student attitudes and behavior, classroom processes and learning environment, and teacher satisfaction. The authors report that statistical integration of the existing research…

Research on Group Learning and Cognitive Science: A Study of Motivation, Knowledge, and Self-Regulation in a Large Lecture College Algebra Class

ERIC Educational Resources Information Center

Miller, David; Schraeder, Matthew

2015-01-01

At a research University near the east coast, researchers restructured a College Algebra course by formatting the course into two large lectures a week, an active recitation size laboratory class once a week, and an extra day devoted to active group work called Supplemental Practice (SP). SP was added as an extra day of class where the SP leader…

A Practical Method of Policy Analysis by Estimating Effect Size

ERIC Educational Resources Information Center

Phelps, James L.

2011-01-01

The previous articles on class size and other productivity research paint a complex and confusing picture of the relationship between policy variables and student achievement. Missing is a conceptual scheme capable of combining the seemingly unrelated research and dissimilar estimates of effect size into a unified structure for policy analysis and…

Why Does Rebalancing Class-Unbalanced Data Improve AUC for Linear Discriminant Analysis?

PubMed

Xue, Jing-Hao; Hall, Peter

2015-05-01

Many established classifiers fail to identify the minority class when it is much smaller than the majority class. To tackle this problem, researchers often first rebalance the class sizes in the training dataset, through oversampling the minority class or undersampling the majority class, and then use the rebalanced data to train the classifiers. This leads to interesting empirical patterns. In particular, using the rebalanced training data can often improve the area under the receiver operating characteristic curve (AUC) for the original, unbalanced test data. The AUC is a widely-used quantitative measure of classification performance, but the property that it increases with rebalancing has, as yet, no theoretical explanation. In this note, using Gaussian-based linear discriminant analysis (LDA) as the classifier, we demonstrate that, at least for LDA, there is an intrinsic, positive relationship between the rebalancing of class sizes and the improvement of AUC. We show that the largest improvement of AUC is achieved, asymptotically, when the two classes are fully rebalanced to be of equal sizes.

Class Size and Student Outcomes: Research and Policy Implications

ERIC Educational Resources Information Center

Chingos, Matthew M.

2013-01-01

Schools across the United States are facing budgetary pressures on a scale not seen in generations. Times of fiscal exigency force policymakers and education practitioners to pay more attention to the return on various categories of public investment in education. The sizes of the classes in which students are educated are often a focus of these…

A Comparison of QEIA and Non-QEIA Schools: Implications of Class Size Reduction

ERIC Educational Resources Information Center

Platt, Louise Carolyn Sater

2013-01-01

The purpose of this research study is to compare student achievement changes between matched QEIA and non-QEIA schools in an effort to infer effects of the most significant feature of QEIA funding, class size reduction. The study addressed the critical question--are there demonstrated, significant differences in student achievement gains between…

Capitalizando en los cursos pequenos (Capitalizing on Small Class Size). ERIC Digest.

ERIC Educational Resources Information Center

O'Connell, Jessica; Smith, Stuart C.

This digest in Spanish examines school districts' efforts to reap the greatest benefit from smaller classes. Although the report discusses teaching strategies that are most effective in small classes, research has shown that teachers do not significantly change their teaching practices when they move from larger to smaller classes. Although…

Empirical study of seven data mining algorithms on different characteristics of datasets for biomedical classification applications.

PubMed

Zhang, Yiyan; Xin, Yi; Li, Qin; Ma, Jianshe; Li, Shuai; Lv, Xiaodan; Lv, Weiqi

2017-11-02

Various kinds of data mining algorithms are continuously raised with the development of related disciplines. The applicable scopes and their performances of these algorithms are different. Hence, finding a suitable algorithm for a dataset is becoming an important emphasis for biomedical researchers to solve practical problems promptly. In this paper, seven kinds of sophisticated active algorithms, namely, C4.5, support vector machine, AdaBoost, k-nearest neighbor, naïve Bayes, random forest, and logistic regression, were selected as the research objects. The seven algorithms were applied to the 12 top-click UCI public datasets with the task of classification, and their performances were compared through induction and analysis. The sample size, number of attributes, number of missing values, and the sample size of each class, correlation coefficients between variables, class entropy of task variable, and the ratio of the sample size of the largest class to the least class were calculated to character the 12 research datasets. The two ensemble algorithms reach high accuracy of classification on most datasets. Moreover, random forest performs better than AdaBoost on the unbalanced dataset of the multi-class task. Simple algorithms, such as the naïve Bayes and logistic regression model are suitable for a small dataset with high correlation between the task and other non-task attribute variables. K-nearest neighbor and C4.5 decision tree algorithms perform well on binary- and multi-class task datasets. Support vector machine is more adept on the balanced small dataset of the binary-class task. No algorithm can maintain the best performance in all datasets. The applicability of the seven data mining algorithms on the datasets with different characteristics was summarized to provide a reference for biomedical researchers or beginners in different fields.

Class Size and Teacher Load in High School English. New York State English Council Monography No. 8.

ERIC Educational Resources Information Center

Wade, Durlyn E.

To determine the class size and teaching load of secondary teachers of English in New York state, the Research Committee of the State English Council mailed 1,093 questionnaires to chairmen of English Departments in the state's registered public and private secondary schools. The 694 usable replies--representing 4,410 full-time English…

An Analysis of the Perceptions and Resources of Large University Classes

ERIC Educational Resources Information Center

Cash, Ceilidh Barlow; Letargo, Jessa; Graether, Steffen P.; Jacobs, Shoshanah R.

2017-01-01

Large class learning is a reality that is not exclusive to the first-year experience at midsized, comprehensive universities; upper-year courses have similarly high enrollment, with many class sizes greater than 200 students. Research into the efficacy and deficiencies of large undergraduate classes has been ongoing for more than 100 years, with…

A Review of Research on Project STAR and Path Ahead

ERIC Educational Resources Information Center

Sohn, Kitae

2016-01-01

Understanding the effects of class size reduction (CSR) has been an enduring issue in education. For the past 3 decades, Project STAR has stimulated research and policy discussions regarding the effects of CSR on a variety of outcomes. Schanzenbach (2007) reviewed STAR studies and concluded that small classes improved student academic outcomes.…

Class Extraction and Classification Accuracy in Latent Class Models

ERIC Educational Resources Information Center

Wu, Qiong

2009-01-01

Despite the increasing popularity of latent class models (LCM) in educational research, methodological studies have not yet accumulated much information on the appropriate application of this modeling technique, especially with regard to requirement on sample size and number of indicators. This dissertation study represented an initial attempt to…

Enhancement of students’ creative thinking skills on mixture separation topic using project based student worksheet

NASA Astrophysics Data System (ADS)

Nurisalfah, R.; Fadiawati, N.; Jalmo, T.

2018-05-01

The aim of this study is to describe the effectiveness of project based student worksheet in improving students' creative thinking skills. The research method is using quasi experiment with the matching only pre-test post-test control group design. The population in this research is all students of class VII SMP N 2 Belitang Madang Raya with class VII1 as control class and class VII4 as experiment class. The sample of this research is obtaining by purposive sampling technique. The effectiveness of project based student worksheet is based on significant post-test differences between the control class and the experiment class as well as the effect size. The results show that the using of project based student worksheet is effective in improving students' creative thinking skills on mixture separation topic.

Big Class Size Challenges: Teaching Reading in Primary Classes in Kampala, Uganda's Central Municipality

ERIC Educational Resources Information Center

Kewaza, Samuel; Welch, Myrtle I.

2013-01-01

Research on reading has established that reading is a pivotal discipline and early literacy development dictates later reading success. Therefore, the purpose of this study is to investigate challenges encountered with reading pedagogy, teaching materials, and teachers' attitudes towards teaching reading in crowded primary classes in Kampala,…

What the Research Says about Class Size, Professional Development, and Recruitment, Induction, and Retention of Highly Qualified Teachers: A Compendium of the Evidence on Title II, Part A, Program-Funded Strategies

ERIC Educational Resources Information Center

Krasnoff, Basha

2015-01-01

States and districts have the flexibility to creatively use Title II, Part A funds to address teacher quality issues. Currently, three strategies predominate--class size reduction, professional development, and recruitment, induction, and retention of highly qualified teachers. Each strategy is implemented with the intention of improving teaching…

Examining the Effect of Class Size on Classroom Engagement and Teacher-Pupil Interaction: Differences in Relation to Pupil Prior Attainment and Primary vs. Secondary Schools

ERIC Educational Resources Information Center

Blatchford, Peter; Bassett, Paul; Brown, Penelope

2011-01-01

It is widely recognized that we need to know more about effects of class size on classroom interactions and pupil behavior. This paper extends research by comparing effects on pupil classroom engagement and teacher-pupil interaction, and examining if effects vary by pupil attainment level and between primary and secondary schools. Systematic…

Rethinking police training policies: large class sizes increase risk of police sexual misconduct.

PubMed

Reingle Gonzalez, Jennifer M; Bishopp, Stephen A; Jetelina, Katelyn K

2016-09-01

The limited research on police sexual misconduct (PSM), a common form of police misconduct, suggests that no evidence-based strategies for prevention are available for use by police departments. To identify new avenues for prevention, we critically evaluated 'front-end' police recruiting, screening, hiring and training procedures. Internal Affairs records were linked with administrative reports and police academy graduation data for officers accused of sexual assault or misconduct between 1994 and 2014. Logistic and proportional hazards regression methods were used to identify predictors of discharge for sustained allegations of PSM and time to discharge, respectively. Officer's graduating class size was positively associated with odds of discharge for PSM. For every one-officer increase in class size, the rate of discharge for PSM increased by 9% [hazard ratio (HR) = 1.09, P < 0.01]. For particularly large classes (>35 graduates), discharge rates were at least four times greater than smaller classes (HR = 4.43, P < 0.05). Large class sizes and more annual graduates increase rates of PSM. Officer recruitment strategies or training quality may be compromised during periods of intensive hiring. Trainee to instructor ratios or maximum class sizes may be instituted by academies to ensure that all police trainees receive the required supervision, one-on-one training, feedback and attention necessary to maximize public safety. © The Author 2015. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Market Size and Innovation: Effects of Medicare Part D on Pharmaceutical Research and Development

PubMed Central

Sood, Neeraj

2012-01-01

Recent evidence suggests that Medicare Part D increased prescription drug use among seniors, and increased pharmaceutical firms’ revenues from sales. Previous studies also indicate that increases in market size induce pharmaceutical innovation. This paper assesses the impact of the Medicare Part D legislation on pharmaceutical research and development (R&D), using time-series data on the number of drugs entering preclinical and clinical development by therapeutic class and phase. We find that the passage and implementation of Medicare Part D is associated with significant increases in pharmaceutical R&D for therapeutic classes with higher Medicare market share. PMID:23869113

Reliability and agreement in student ratings of the class environment.

PubMed

Nelson, Peter M; Christ, Theodore J

2016-09-01

The current study estimated the reliability and agreement of student ratings of the classroom environment obtained using the Responsive Environmental Assessment for Classroom Teaching (REACT; Christ, Nelson, & Demers, 2012; Nelson, Demers, & Christ, 2014). Coefficient alpha, class-level reliability, and class agreement indices were evaluated as each index provides important information for different interpretations and uses of student rating scale data. Data for 84 classes across 29 teachers in a suburban middle school were sampled to derive reliability and agreement indices for the REACT subscales across 4 class sizes: 25, 20, 15, and 10. All participating teachers were White and a larger number of 6th-grade classes were included (42%) relative to 7th- (33%) or 8th- (23%) grade classes. Teachers were responsible for a variety of content areas, including language arts (26%), science (26%), math (20%), social studies (19%), communications (6%), and Spanish (3%). Coefficient alpha estimates were generally high across all subscales and class sizes (α = .70-.95); class-mean estimates were greatly impacted by the number of students sampled from each class, with class-level reliability values generally falling below .70 when class size was reduced from 25 to 20. Further, within-class student agreement varied widely across the REACT subscales (mean agreement = .41-.80). Although coefficient alpha and test-retest reliability are commonly reported in research with student rating scales, class-level reliability and agreement are not. The observed differences across coefficient alpha, class-level reliability, and agreement indices provide evidence for evaluating students' ratings of the class environment according to their intended use (e.g., differentiating between classes, class-level instructional decisions). (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Democracy and Higher Education: The Nature of the Relationship

ERIC Educational Resources Information Center

Holland, Lauren

2009-01-01

This study examines the pedagogical conditions that contribute to political learning in American National Government courses, using data from classes taught at universities and colleges in Utah. The purpose of this research is to assess the relative effect of course content, classroom climate, textbook, institutional ranking and class size on…

Reclaiming Assessment through Accountability that Is "Just Right"

ERIC Educational Resources Information Center

Graue, Elizabeth; Johnson, Erica

2011-01-01

Background: This article builds on three years of qualitative research on Wisconsin's Student Achievement Guarantee in Education (SAGE) program, a class size reduction policy in Wisconsin. Objective: In this article, we take a practice-oriented perspective on assessment, examining how assessments in schools that participated in a class size…

Meta-analysis: An Approach to the Synthesis of Research Results.

ERIC Educational Resources Information Center

Glass, Gene V.

1982-01-01

Discusses three general characteristics and four criticisms of meta-analysis (statistical analysis of the summary findings of many research studies). Illustrates application of meta-analysis on research studies relating to school class size and achievement and inquiry teaching of biology. (JN)

The Effectiveness of learning materials based on multiple intelligence on the understanding of global warming

NASA Astrophysics Data System (ADS)

Liliawati, W.; Purwanto; Zulfikar, A.; Kamal, R. N.

2018-05-01

This study aims to examine the effectiveness of the use of teaching materials based on multiple intelligences on the understanding of high school students’ material on the theme of global warming. The research method used is static-group pretest-posttest design. Participants of the study were 60 high school students of XI class in one of the high schools in Bandung. Participants were divided into two classes of 30 students each for the experimental class and control class. The experimental class uses compound-based teaching materials while the experimental class does not use a compound intelligence-based teaching material. The instrument used is a test of understanding of the concept of global warming with multiple choices form amounted to 15 questions and 5 essay items. The test is given before and after it is applied to both classes. Data analysis using N-gain and effect size. The results obtained that the N-gain for both classes is in the medium category and the effectiveness of the use of teaching materials based on the results of effect-size test results obtained in the high category.

A mechanistic assessment of seasonal microhabitat selection by drift-feeding rainbow trout Oncorhynchus mykiss in a southwestern headwater stream

USGS Publications Warehouse

Kalb, Bradley W.; Huntsman, Brock M.; Caldwell, Colleen A.; Bozek, Michael A.

2018-01-01

The positioning of fishes within a riverscape is dependent on the proximity of complementary habitats. In this study, foraging and non-foraging habitat were quantified monthly over an entire year for a rainbow trout (Oncorhynchus mykiss) population in an isolated, headwater stream in southcentral New Mexico. The stream follows a seasonal thermal and hydrologic pattern typical for a Southwestern stream and was deemed suitable for re-introduction of the native and close relative, Rio Grande cutthroat trout (O. clarkii virginalis). However, uncertainty associated with limited habitat needed to be resolved if repatriation of the native fish was to be successful. Habitat was evaluated using resource selection functions with a mechanistic drift-foraging model to explain trout distributions. Macroinvertebrate drift was strongly season- and temperature-dependent (lower in winter and spring, higher in summer and fall). Models identified stream depth as the most limiting factor for habitat selection across seasons and size-classes. Additionally, positions closer to cover were selected during the winter by smaller size-classes (0, 1, 2), while net energy intake was important during the spring for most size-classes (0, 1, 2, 3). Drift-foraging models identified that 81% of observed trout selected positions that could meet maintenance levels throughout the year. Moreover, 40% of selected habitats could sustain maximum growth. Stream positions occupied by rainbow trout were more energetically profitable than random sites regardless of season or size-class. Larger size-classes (3, 4+) were energetically more limited throughout the year than were smaller size-classes. This research suggests that habitat in the form of deep pools is of paramount importance for rainbow trout or native cutthroat trout.

Environmental characteristics and student physical activity in PE class: findings from two large urban areas of Texas.

PubMed

Skala, Katherine A; Springer, Andrew E; Sharma, Shreela V; Hoelscher, Deanna M; Kelder, Steven H

2012-05-01

Physical education (PE) classes provide opportunities for children to be active. This study examined the associations between specific environmental characteristics (teacher characteristics; class size, duration and location; and lesson context) and elementary school-aged children's moderate-to-vigorous activity (MVPA) during PE. Environmental characteristics and student activity levels were measured in 211 third-, fourth-, and fifth-grade PE classes in 74 Texas public schools using SOFIT direct observation. Students engaged in less than half their PE class time in MVPA (38%), while approximately 25% of class time was spent in classroom management. Percent time in MVPA was significantly higher in outdoor classes compared with indoors (41.4% vs. 36.1%, P = .037). Larger (P = .044) and longer (P = .001) classes were negatively associated with percentage of MVPA and positively correlated with time spent in management (P < .001). Findings suggest that children's activity may be influenced by environmental factors such as class size, location, and lesson contexts. These findings hold important policy implications for PE class organization and the need for strategies that maximize children's MVPA. Further research is needed to test the causal association of these factors with student MVPA.

Assessing Facilitator Performance as an Influence on Student Satisfaction

ERIC Educational Resources Information Center

Dunlap, Scotty; May, David

2011-01-01

Growth in class size within the online environment has resulted in a facilitator model in which an instructor teaches the class with the assistance of facilitators who interact with students in smaller groups. This research sought to determine the effectiveness of a structured performance evaluation for facilitators and the correlation to student…

SYNTHESIS AND APPLICATION OF A NEW CLASS OF STABILIZED NANOSCALE IRON PARTICLES FOR RAPID DESTRUCTION OF CHLORINATED HYDROCARBONS IN SOIL AND GROUNDWATER

EPA Science Inventory

In accord with the research objectives, this project achieved the following major results:

1. Developed a new method for synthesizing a new class of starch- or carboxymethyl cellulose stabilized ZVI nanoparticles of controllable size and transportability. ...

2. Comparative Evaluation of Online and In-Class Student Team Presentations

   ERIC Educational Resources Information Center

   Braun, Michael

   2017-01-01

   Student team presentations are commonly utilised in tertiary science courses to help students develop skills in communication, teamwork and literature research, but they are subject to constraints arising from class size, available time, and limited facilities. In an alternative approach, student teams present online using a variety of tools, such…

3. New Concepts and Perspectives on Micro-Rotorcraft and Small Autonomous Rotary-Wing Vehicles

   NASA Technical Reports Server (NTRS)

   Young, Larry A.; Aiken, E. W.; Johnson, J. L.; Demblewski, R.; Andrews, J.; Aiken, Irwin W. (Technical Monitor)

   2001-01-01

   A key part of the strategic vision for rotorcraft research as identified by senior technologists within the Army/NASA Rotorcraft Division at NASA Ames Research Center is the development and use of small autonomous rotorcraft. Small autonomous rotorcraft are defined for the purposes of this paper to be a class of vehicles that range in size from rotary-wing micro air vehicles (MAVs) to larger, more conventionally sized, rotorcraft uninhabited aerial vehicles (UAVs) - i.e. vehicle gross weights ranging from hundreds of grams to thousands of kilograms. The development of small autonomous rotorcraft represents both a technology challenge and a potential new vehicle class that will have substantial societal impact for: national security, personal transport, planetary science, and public service.

Do School Facilities Affect Academic Outcomes?

ERIC Educational Resources Information Center

Schneider, Mark

This review explores which facility attributes affect academic outcomes the most and in what manner and degree. The research is examined in six categories: indoor air quality, ventilation, and thermal comfort; lighting; acoustics; building age and quality; school size; and class size. The review concludes that school facilities affect learning.…

Will Parents and Teachers Get on the Bandwagon To Reduce Class Size?

ERIC Educational Resources Information Center

Johnson, Jean

2002-01-01

Presents several questions and answers about small high schools based on Public Agenda (a nonprofit research organization in New York City) survey of 920 public high school teachers and 801 parents of students enrolled in public high schools. Discusses community issues related to reducing school size. (PKP)

Class-Size Effects in Secondary School

ERIC Educational Resources Information Center

Krassel, Karl Fritjof; Heinesen, Eskil

2014-01-01

We analyze class-size effects on academic achievement in secondary school in Denmark exploiting an institutional setting where pupils cannot predict class size prior to enrollment, and where post-enrollment responses aimed at affecting realized class size are unlikely. We identify class-size effects combining a regression discontinuity design with…

Class Enumeration and Parameter Recovery of Growth Mixture Modeling and Second-Order Growth Mixture Modeling in the Presence of Measurement Noninvariance between Latent Classes

PubMed Central

Kim, Eun Sook; Wang, Yan

2017-01-01

Population heterogeneity in growth trajectories can be detected with growth mixture modeling (GMM). It is common that researchers compute composite scores of repeated measures and use them as multiple indicators of growth factors (baseline performance and growth) assuming measurement invariance between latent classes. Considering that the assumption of measurement invariance does not always hold, we investigate the impact of measurement noninvariance on class enumeration and parameter recovery in GMM through a Monte Carlo simulation study (Study 1). In Study 2, we examine the class enumeration and parameter recovery of the second-order growth mixture modeling (SOGMM) that incorporates measurement models at the first order level. Thus, SOGMM estimates growth trajectory parameters with reliable sources of variance, that is, common factor variance of repeated measures and allows heterogeneity in measurement parameters between latent classes. The class enumeration rates are examined with information criteria such as AIC, BIC, sample-size adjusted BIC, and hierarchical BIC under various simulation conditions. The results of Study 1 showed that the parameter estimates of baseline performance and growth factor means were biased to the degree of measurement noninvariance even when the correct number of latent classes was extracted. In Study 2, the class enumeration accuracy of SOGMM depended on information criteria, class separation, and sample size. The estimates of baseline performance and growth factor mean differences between classes were generally unbiased but the size of measurement noninvariance was underestimated. Overall, SOGMM is advantageous in that it yields unbiased estimates of growth trajectory parameters and more accurate class enumeration compared to GMM by incorporating measurement models. PMID:28928691

Pharmacy Residency School-wide Match Rates and Modifiable Predictors in ACPE-accredited Colleges and Schools of Pharmacy

PubMed Central

Whittaker, Alana; Shan, Guogen

2017-01-01

Objective. To analyze the modifiable predictors of institution-wide residency match rates. Methods. This was a retrospective analysis of colleges and schools of pharmacy data and school-wide PGY-1 pharmacy residency match rates for 2013 through 2015. Independent variables included NAPLEX passing rates, history of ACPE probation, NIH funding, academic health center affiliation, dual-degree availability, program length, admit-to-applicant ratio, class size, tuition, student-driven research, clinically focused academic tracks, residency affiliation, U.S. News & World Report rankings, and minority enrollment. Results. In a repeated measures model, predictors of match results were NAPLEX pass rate, class size, academic health center affiliation, admit-to-applicant ratio, U.S. News & World Report rankings, and minority enrollment. Conclusion. Indicators of student achievement, college/school reputation, affiliations, and class demographics were significant predictors of institution-wide residency match rates. Further research is needed to understand how changes in these factors may influence overall match rates. PMID:29367773

Pharmacy Residency School-wide Match Rates and Modifiable Predictors in ACPE-accredited Colleges and Schools of Pharmacy.

PubMed

Whittaker, Alana; Smith, Katherine P; Shan, Guogen

2017-12-01

Objective. To analyze the modifiable predictors of institution-wide residency match rates. Methods. This was a retrospective analysis of colleges and schools of pharmacy data and school-wide PGY-1 pharmacy residency match rates for 2013 through 2015. Independent variables included NAPLEX passing rates, history of ACPE probation, NIH funding, academic health center affiliation, dual-degree availability, program length, admit-to-applicant ratio, class size, tuition, student-driven research, clinically focused academic tracks, residency affiliation, U.S. News & World Report rankings, and minority enrollment. Results. In a repeated measures model, predictors of match results were NAPLEX pass rate, class size, academic health center affiliation, admit-to-applicant ratio, U.S. News & World Report rankings, and minority enrollment. Conclusion. Indicators of student achievement, college/school reputation, affiliations, and class demographics were significant predictors of institution-wide residency match rates. Further research is needed to understand how changes in these factors may influence overall match rates.

An Analysis of the Perceptions and Resources of Large University Classes

PubMed Central

Cash, Ceilidh Barlow; Letargo, Jessa; Graether, Steffen P.; Jacobs, Shoshanah R.

2017-01-01

Large class learning is a reality that is not exclusive to the first-year experience at midsized, comprehensive universities; upper-year courses have similarly high enrollment, with many class sizes greater than 200 students. Research into the efficacy and deficiencies of large undergraduate classes has been ongoing for more than 100 years, with most research associating large classes with weak student engagement, decreased depth of learning, and ineffective interactions. This study used a multidimensional research approach to survey student and instructor perceptions of large biology classes and to characterize the courses offered by a department according to resources and course structure using a categorical principal components analysis. Both student and instructor survey results indicated that a large class begins around 240 students. Large classes were identified as impersonal and classified using extrinsic qualifiers; however, students did identify techniques that made the classes feel smaller. In addition to the qualitative survey, we also attempted to quantify courses by collecting data from course outlines and analyzed the data using categorical principal component analysis. The analysis maps institutional change in resource allocation and teaching structure from 2010 through 2014 and validates the use of categorical principal components analysis in educational research. We examine what perceptions and factors are involved in a large class that is perceived to feel small. Our analysis suggests that it is not the addition of resources or difference in the lecturing method, but it is the instructor that determines whether a large class can feel small. PMID:28495937

Influence of Group Size on Students' Participation in Online Discussion Forums

ERIC Educational Resources Information Center

Kim, Jungjoo

2013-01-01

This study attempts to examine how students participate and interact in different discussion modules organized with different group size in an online environment. It adopts a case study methodology where full semester online course with two small-group and three class-wide discussion forums was examined. The researcher counted the number of…

The Determinants of Parental Effort in Education Production: Do Parents Respond to Changes in Class Size?

ERIC Educational Resources Information Center

Bonesronning, Hans

2004-01-01

The present paper supplements the traditional class size literature by exploring the causal relationship between class size and parental effort in education production. Class size variation that is exogenous to parental effort comes from interaction between enrollment and a maximum class size rule of 30 students in the lower secondary school in…

Enhancing Teaching Effectiveness Using Experiential Techniques: Model Development and Empirical Evaluation.

ERIC Educational Resources Information Center

Wagner, Richard J.; And Others

In U.S. colleges and universities, much attention has been focused on the need to improve teaching quality and to involve students in the learning process. At the same time, many faculty members are faced with growing class sizes and with time pressures due to research demands. One useful technique is to divide the class into small groups and…

Ethnicity, Gender, Social Class and Achievement Gaps at Age 16: Intersectionality and "Getting It" for the White Working Class

ERIC Educational Resources Information Center

Strand, Steve

2014-01-01

Perhaps the most prevailing inequalities in educational achievement in England are those associated with socio-economic status (SES), ethnicity and gender. However, little research has sought to compare the relative size of these gaps or to explore interactions between these factors. This paper analyses the educational achievement at age 11, 14…

76 FR 27306 - Endangered Species; File No. 15661

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-11

... conduct research on sea turtles to characterize population structure, size class composition, foraging ecology, and migration patterns for green and hawksbill sea turtles in the Northern Mariana Islands with...

Use of alligator hole abundance and occupancy rate as indicators for restoration of a human-altered wetland

USGS Publications Warehouse

Fujisaki, Ikuko; Mazzotti, Frank J.; Hart, Kristen M.; Rice, Kenneth G.; Ogurcak, Danielle; Rochford, Michael; Jeffery, Brian M.; Brandt, Laura A.; Cherkiss, Michael S.

2012-01-01

Use of indicator species as a measure of ecosystem conditions is an established science application in environmental management. Because of its role in shaping wetland systems, the American alligator (Alligator mississippiensis) is one of the ecological indicators for wetland restoration in south Florida, USA. We conducted landscape-level aerial surveys of alligator holes in two different habitats in a wetland where anthropogenic modification of surface hydrology has altered the natural system. Alligator holes were scarcer in an area where modified hydrology caused draining and frequent dry-downs compared to another area that maintains a functional wetland system. Lower abundance of alligator holes indicates lack of alligator activities, lower overall species diversity, and lack of dry-season aquatic refugia for other organisms. The occupancy rate of alligator holes was lower than the current restoration target for the Everglades, and was variable by size class with large size-class alligators predominantly occupying alligator holes. This may indicate unequal size-class distribution, different habitat selection by size classes, or possibly a lack of recruitment. Our study provides pre-restoration baseline information about one indicator species for the Everglades. Success of the restoration can be assessed via effective synthesis of information derived by collective research efforts on the entire suite of selected ecological indicators.

Meteor research program

NASA Technical Reports Server (NTRS)

Southworth, R. B.; Mccrosky, R. E.

1970-01-01

An overview of research on radio and radar meteors accomplished during the past decade is presented, and the work of the past year is highlighted. Velocity distribution and mass flux data are obtained for meteors in the range 10 to 0.0001 g, the size believed to be the principal hazard to space missions. The physical characteristics of mass, structure and density, luminosity, and ablation are briefly described, and the formulation of a theory for interactions of ionization and excitation during collision of atomic particles is mentioned. Five classes of meteoroids are identified, including the two of iron and stone meteorites. Stream meteors associated with known comets are Classes A or C, and parent comets of Class B streams are not observed. Class A meteoroids are identified with the core of a cometary nucleus, Class C with less dense surface of the nucleus after sublimation of ices, and Class B with less dense cores of smaller cometary nuclei. Atmospheric meteor phenomena associated with winds and gravity waves, density and temperature, atomic oxygen, and meteor rate changes are mentioned.

Striving to Involve Undergraduates in Economic Research at Wellesley College

ERIC Educational Resources Information Center

Butcher, Kristin F.; Weerapana, Akila

2017-01-01

One of the key advantages of attending a small liberal arts college is the opportunity to engage in research; at research universities, these opportunities are often given to graduate students. Further, smaller class sizes make it possible to personalize instruction to showcase how the tools students learn in their courses are used to answer…

Multi-Positioning Mathematics Class Size: Teachers' Views

ERIC Educational Resources Information Center

Handal, Boris; Watson, Kevin; Maher, Marguerite

2015-01-01

This paper explores mathematics teachers' perceptions about class size and the impact class size has on teaching and learning in secondary mathematics classrooms. It seeks to understand teachers' views about optimal class sizes and their thoughts about the education variables that influence these views. The paper draws on questionnaire responses…

Do Reductions in Class Size Raise Students' Test Scores? Evidence from Population Variation in Minnesota's Elementary Schools

ERIC Educational Resources Information Center

Cho, Hyunkuk; Glewwe, Paul; Whitler, Melissa

2012-01-01

Many U.S. states and cities spend substantial funds to reduce class size, especially in elementary (primary) school. Estimating the impact of class size on learning is complicated, since children in small and large classes differ in many observed and unobserved ways. This paper uses a method of Hoxby (2000) to assess the impact of class size on…

Do Class Size Effects Differ across Grades?

ERIC Educational Resources Information Center

Nandrup, Anne Brink

2016-01-01

This paper contributes to the class size literature by analysing whether short-run class size effects are constant across grade levels in compulsory school. Results are based on administrative data on all pupils enrolled in Danish public schools. Identification is based on a government-imposed class size cap that creates exogenous variation in…

The Synergy of Class Size Reduction and Classroom Quality

ERIC Educational Resources Information Center

Graue, Elizabeth; Rauscher, Erica; Sherfinski, Melissa

2009-01-01

A contextual approach to understanding class size reduction includes attention to both educational inputs and processes. Based on our study of a class size reduction program in Wisconsin we explore the following question: How do class size reduction and classroom quality interact to produce learning opportunities in early elementary classrooms? To…

Adopting a Blended Learning Approach: Challenges Encountered and Lessons Learned in an Action Research Study

ERIC Educational Resources Information Center

Kenney, Jane; Newcombe, Ellen

2011-01-01

Adopting a new teaching approach is often a daunting task especially if one is an early adopter in a limited-resource environment. This article describes the challenges encountered and the strategies used in pilot testing a blended instructional method in a large size class within the college of education at a medium-sized university. The main…

Does Big-Fish-Little-Pond Effect Always Exist? Investigation of Goal Orientations as Moderators in the Hong Kong Context

ERIC Educational Resources Information Center

Cheng, Rebecca Wing-yi; McInerney, Dennis M.; Mok, Magdalena Mo Ching

2014-01-01

The big-fish-little-pond effect (BFLPE) posits that students with the same ability will have higher academic self-concepts when they are in low-ability classes than in high-ability classes. Our research puts the BFLPE under scrutiny by examining goal orientations as the moderators that may affect the size of the BFLPE. We collected data on…

Putting Institutional Research to Work in the Smaller College.

ERIC Educational Resources Information Center

Stivers, Earl R.

The aims of institutional research should be to: (1) provide a basis for future planning, e.g., enrollment projections and criteria for accepting applications, (2) determine the effectiveness of space utilization, such as use of each instructional room, free hours of each, comparisons of class sizes with designed room capacities, discovery of…

Class Size Effects on Fourth-Grade Mathematics Achievement: Evidence from TIMSS 2011

ERIC Educational Resources Information Center

Li, Wei; Konstantopoulos, Spyros

2016-01-01

Class size reduction policies have been widely implemented around the world in recent years. However, findings about the effects of class size on student achievement have been mixed. This study examines class size effects on fourth-grade mathematics achievement in 14 European countries using data from TIMSS (Trends in International Mathematics and…

Primary Class Size Reduction: How Policy Space, Physical Space, and Spatiality Shape What Happens in Real Schools

ERIC Educational Resources Information Center

Bascia, Nina; Faubert, Brenton

2012-01-01

This article reviews the literature base on class size reduction and proposes a new analytic framework that we believe provides practically useful explanations of how primary class size reduction works. It presents descriptions of classroom practice and grounded explanations for how class size reduction affects educational core activities by…

Class Size Effects on Mathematics Achievement in Cyprus: Evidence from TIMSS

ERIC Educational Resources Information Center

Konstantopoulos, Spyros; Shen, Ting

2016-01-01

Class size reduction has been viewed as one school mechanism that can improve student achievement. Nonetheless, the literature has reported mixed findings about class size effects. We used 4th- and 8th-grade data from TIMSS 2003 and 2007 to examine the association between class size and mathematics achievement in public schools in Cyprus. We…

Class-Size Policy: The STAR Experiment and Related Class-Size Studies. NCPEA Policy Brief. Volume 1, Number 2

ERIC Educational Resources Information Center

Achilles, Charles M.

2012-01-01

This brief summarizes findings on class size from over 25 years of work on the Tennessee Student Teacher Achievement Ratio (STAR) randomized, longitudinal experiment, and other Class-Size Reduction (CSR) studies throughout the United States, Australia, Hong Kong, Sweden, Great Britain, and elsewhere. The brief concludes with recommendations. The…

The Use of Growth Mixture Modeling for Studying Resilience to Major Life Stressors in Adulthood and Old Age: Lessons for Class Size and Identification and Model Selection.

PubMed

Infurna, Frank J; Grimm, Kevin J

2017-12-15

Growth mixture modeling (GMM) combines latent growth curve and mixture modeling approaches and is typically used to identify discrete trajectories following major life stressors (MLS). However, GMM is often applied to data that does not meet the statistical assumptions of the model (e.g., within-class normality) and researchers often do not test additional model constraints (e.g., homogeneity of variance across classes), which can lead to incorrect conclusions regarding the number and nature of the trajectories. We evaluate how these methodological assumptions influence trajectory size and identification in the study of resilience to MLS. We use data on changes in subjective well-being and depressive symptoms following spousal loss from the HILDA and HRS. Findings drastically differ when constraining the variances to be homogenous versus heterogeneous across trajectories, with overextraction being more common when constraining the variances to be homogeneous across trajectories. In instances, when the data are non-normally distributed, assuming normally distributed data increases the extraction of latent classes. Our findings showcase that the assumptions typically underlying GMM are not tenable, influencing trajectory size and identification and most importantly, misinforming conceptual models of resilience. The discussion focuses on how GMM can be leveraged to effectively examine trajectories of adaptation following MLS and avenues for future research. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

College Climate and Teacher-Trainee's Academic Work in Selected Colleges of Education in the Ashanti Region of Ghana

ERIC Educational Resources Information Center

Adjei, Augustine; Dontoh, Samuel; Baafi-Frimpong, Stephen

2017-01-01

The study aimed at investigating the extent to which College climate (Leadership roles/practices and Class size) impact on academic work of Teacher-trainees. A survey research design was used for the study because it involved a study of relatively large population who were purposively and randomly selected. A sample size of 322 out of the…

The Kinematic Analysis of Flat Leverage Mechanism of the Third Class

NASA Astrophysics Data System (ADS)

Zhauyt, A.; Mamatova, G.; Abdugaliyeva, G.; Alipov, K.; Sakenova, A.; Alimbetov, A.

2017-10-01

It is necessary to make link mechanisms calculation to the strength at designing of flat link mechanisms of high class after definition of block diagrams and link linear sizes i.e. it is rationally to choose their forms and to determine the section sizes. The algorithm of the definition of dimension of link mechanism lengths of high classes (MHC) and their metric parameters at successive approach is offered in this work. It this paper educational and research software named GIM is presented. This software has been developed with the aim of approaching the difficulties students usually encounter when facing up to kinematic analysis of mechanisms. A deep understanding of the kinematic analysis is necessary to go a step further into design and synthesis of mechanisms. In order to support and complement the theoretical lectures, GIM software is used during the practical exercises, serving as an educational complementary tool reinforcing the knowledge acquired by the students.

Effect of roasting degree on the antioxidant activity of different Arabica coffee quality classes.

PubMed

Odžaković, Božana; Džinić, Natalija; Kukrić, Zoran; Grujić, Slavica

2016-01-01

Coffee is one of the most widely consumed beverages in the world, because of its unique sensory properties and physiological properties. Coffee beverages represent a significant source of antioxidants in the consumers' diet and contribute significantly to their daily intake. The aim of this research was to investigate the effect of different roasting degrees on the content of biologically active compounds and antioxidant activity in different quality classes of Arabica coffee. Samples of green Arabica coffee (Rio Minas) of two quality classes from two production batches were used for the research. Roasting was carried out at temperatures of 167, 175 and 171°C. The total phenol content (TPC), total flavonoid content (TFC), flavonol content (FC) and antioxidant activity (DPPH, ABTS) in the coffee extracts was determined. This research shows that TPC was significantly higher (P < 0.05) in green coffee compared to TPC in roasted coffee, and TPC decreases as the roasting temperature increases. TFC and FC were significantly lower (P < 0.05) in green coffee than in roasted coffee. Differences in TPC between the 1st and 2nd classes of Arabica coffee were not significant (P > 0.05), while differences in TFC were significant (P < 0.05) only for green coffee from the second production batch and differences in FC were significant (P < 0.05) for green coffee and for coffee roasted at 175°C. Roasting temperatures have different influences the antioxidant activity (DPPH, ABTS) of coffee and the highest antioxidant activity was determined in coffee roasted at 171°C. An exception was 1st class Arabica coffee roasted at 167°C (ABTS). All samples of 1st class Arabica coffee had higher antioxidant activity (DPPH, ABTS) compared to 2nd class Arabica. This research shows that the bioactive compounds content and antioxidant activity of different quality classes of Arabica coffee are dependent on the degree of roasting. TPC decreases when the roasting temperature increases, while TFC and FC also increase. These results indicate that the antioxidant activity of coffee depends on a variety of bioactive components in coffee beans. Antioxidant activity largely depends on the class of coffee. The coffee samples of 1stclass quality (maximum 8 black beans/300 g from the sample and large bean size) had higher antioxidant activity compared to samples of 2nd quality class (maximum 19 black beans/300 g in the sample and medium-sized beans).

Does Class Size Make a Difference?

ERIC Educational Resources Information Center

Glass, Gene V.; Down, A. Graham

1979-01-01

Argues that study findings indicate that lowered class size increases student achievement and improves school attitudes. Counter argument indicates there is little educational payoff and great monetary expense in small reductions in class size. (RH)

Medium- and Heavy-Duty Vehicle Duty Cycles for Electric Powertrains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Kenneth; Bennion, Kevin; Miller, Eric

2016-03-02

NREL's Fleet Test and Evaluation group has extensive in-use vehicle data demonstrating the importance of understanding the vocational duty cycle for appropriate sizing of electric vehicle (EV) and power electronics components for medium- and heavy-duty EV applications. This presentation includes an overview of recent EV fleet evaluation projects that have valuable in-use data that can be leveraged for sub-system research, analysis, and validation. Peak power and power distribution data from in-field EVs are presented for four different vocations, including class 3 delivery vans, class 6 delivery trucks, class 8 transit buses, and class 8 port drayage trucks, demonstrating the impactsmore » of duty cycle on performance requirements.« less

Public School Education: The Case for Reduced Class Size. Why the Present Class Size is Not Working and What Can We Do about It?

ERIC Educational Resources Information Center

Graham, Evol

2009-01-01

By reducing class size we will close the achievement gap in public school education, caused by prior neglect especially since the civil rights era of the sixties. Additional, highly qualified and specialized teachers will more effectively manage a smaller class size and serve more individual student needs in the crucial early grades, where a solid…

Beyond eruptive scenarios: assessing tephra fallout hazard from Neapolitan volcanoes.

PubMed

Sandri, Laura; Costa, Antonio; Selva, Jacopo; Tonini, Roberto; Macedonio, Giovanni; Folch, Arnau; Sulpizio, Roberto

2016-04-12

Assessment of volcanic hazards is necessary for risk mitigation. Typically, hazard assessment is based on one or a few, subjectively chosen representative eruptive scenarios, which use a specific combination of eruptive sizes and intensities to represent a particular size class of eruption. While such eruptive scenarios use a range of representative members to capture a range of eruptive sizes and intensities in order to reflect a wider size class, a scenario approach neglects to account for the intrinsic variability of volcanic eruptions, and implicitly assumes that inter-class size variability (i.e. size difference between different eruptive size classes) dominates over intra-class size variability (i.e. size difference within an eruptive size class), the latter of which is treated as negligible. So far, no quantitative study has been undertaken to verify such an assumption. Here, we adopt a novel Probabilistic Volcanic Hazard Analysis (PVHA) strategy, which accounts for intrinsic eruptive variabilities, to quantify the tephra fallout hazard in the Campania area. We compare the results of the new probabilistic approach with the classical scenario approach. The results allow for determining whether a simplified scenario approach can be considered valid, and for quantifying the bias which arises when full variability is not accounted for.

Summary of an Analysis of Pupil-Teacher Ratio and Class Size: Differences That Make a Difference and Its Implications on Staffing for Class-Size Reduction.

ERIC Educational Resources Information Center

Sharp, Mark A.

The purpose of this paper was to share findings from an earlier study and to provide a framework for administrators to use in the implementation of class-size reduction (CSR) in their buildings. The study examined actual and average class size (CS), pupil-teacher ratios (PTR), and their differences. A primary goal was to clarify the ramifications…

Class Size and Student Diversity: Two Sides of the Same Coin. Teacher Voice

ERIC Educational Resources Information Center

Froese-Germain, Bernie; Riel, Rick; McGahey, Bob

2012-01-01

Among Canadian teacher unions, discussions of class size are increasingly being informed by the importance of considering the diversity of student needs within the classroom (often referred to as class composition). For teachers, both class size and diversity matter. Teachers consistently adapt their teaching to address the individual needs of the…

Class Size Reduction: Implementation and Solutions.

ERIC Educational Resources Information Center

Krieger, Jean

This is a report of a study designed to discover the nature of interactions between teachers and students in regular-size classes (25 or more students) and small-size classes (fewer than 18 students). It also describes the efforts of one public school to maintain smaller classes. A review of the literature and observations of 11 primary classrooms…

Additional Evidence on the Relationship between Class Size and Student Performance

ERIC Educational Resources Information Center

Arias, J. J.; Walker, Douglas M.

2004-01-01

Much of the economic education literature suggests that the principles of economics class size does not significantly affect student performance. However, study methods have varied in terms of the aggregation level (student or class), the measure of performance (TUCE or course letter grade), and the class size measure (e.g., students who completed…

Student evaluations of teaching: teaching quantitative courses can be hazardous to one’s career

PubMed Central

Smibert, Dylan

2017-01-01

Anonymous student evaluations of teaching (SETs) are used by colleges and universities to measure teaching effectiveness and to make decisions about faculty hiring, firing, re-appointment, promotion, tenure, and merit pay. Although numerous studies have found that SETs correlate with various teaching effectiveness irrelevant factors (TEIFs) such as subject, class size, and grading standards, it has been argued that such correlations are small and do not undermine the validity of SETs as measures of professors’ teaching effectiveness. However, previous research has generally used inappropriate parametric statistics and effect sizes to examine and to evaluate the significance of TEIFs on personnel decisions. Accordingly, we examined the influence of quantitative vs. non-quantitative courses on SET ratings and SET based personnel decisions using 14,872 publicly posted class evaluations where each evaluation represents a summary of SET ratings provided by individual students responding in each class. In total, 325,538 individual student evaluations from a US mid-size university contributed to theses class evaluations. The results demonstrate that class subject (math vs. English) is strongly associated with SET ratings, has a substantial impact on professors being labeled satisfactory vs. unsatisfactory and excellent vs. non-excellent, and the impact varies substantially depending on the criteria used to classify professors as satisfactory vs. unsatisfactory. Professors teaching quantitative courses are far more likely not to receive tenure, promotion, and/or merit pay when their performance is evaluated against common standards. PMID:28503380

Student evaluations of teaching: teaching quantitative courses can be hazardous to one's career.

PubMed

Uttl, Bob; Smibert, Dylan

2017-01-01

Anonymous student evaluations of teaching (SETs) are used by colleges and universities to measure teaching effectiveness and to make decisions about faculty hiring, firing, re-appointment, promotion, tenure, and merit pay. Although numerous studies have found that SETs correlate with various teaching effectiveness irrelevant factors (TEIFs) such as subject, class size, and grading standards, it has been argued that such correlations are small and do not undermine the validity of SETs as measures of professors' teaching effectiveness. However, previous research has generally used inappropriate parametric statistics and effect sizes to examine and to evaluate the significance of TEIFs on personnel decisions. Accordingly, we examined the influence of quantitative vs. non-quantitative courses on SET ratings and SET based personnel decisions using 14,872 publicly posted class evaluations where each evaluation represents a summary of SET ratings provided by individual students responding in each class. In total, 325,538 individual student evaluations from a US mid-size university contributed to theses class evaluations. The results demonstrate that class subject (math vs. English) is strongly associated with SET ratings, has a substantial impact on professors being labeled satisfactory vs. unsatisfactory and excellent vs. non-excellent, and the impact varies substantially depending on the criteria used to classify professors as satisfactory vs. unsatisfactory. Professors teaching quantitative courses are far more likely not to receive tenure, promotion, and/or merit pay when their performance is evaluated against common standards.

77 FR 13097 - Endangered Species; File Nos. 15661, 10027, and 15685

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-05

... population structure, size class composition, foraging ecology, and migration patterns for green and... of green and hawksbill sea turtles focusing on distribution and abundance, ecology, health, and... and population structure, foraging ecology, habitat use, and movements. Researchers may capture...

Class Size Effects on Student Achievement: Heterogeneity across Abilities and Fields

ERIC Educational Resources Information Center

De Paola, Maria; Ponzo, Michela; Scoppa, Vincenzo

2013-01-01

In this paper, we analyze class size effects on college students exploiting data from a project offering special remedial courses in mathematics and language skills to freshmen enrolled at an Italian medium-sized public university. To estimate the effects of class size, we exploit the fact that students and teachers are virtually randomly assigned…

Beyond eruptive scenarios: assessing tephra fallout hazard from Neapolitan volcanoes

PubMed Central

Sandri, Laura; Costa, Antonio; Selva, Jacopo; Tonini, Roberto; Macedonio, Giovanni; Folch, Arnau; Sulpizio, Roberto

2016-01-01

Assessment of volcanic hazards is necessary for risk mitigation. Typically, hazard assessment is based on one or a few, subjectively chosen representative eruptive scenarios, which use a specific combination of eruptive sizes and intensities to represent a particular size class of eruption. While such eruptive scenarios use a range of representative members to capture a range of eruptive sizes and intensities in order to reflect a wider size class, a scenario approach neglects to account for the intrinsic variability of volcanic eruptions, and implicitly assumes that inter-class size variability (i.e. size difference between different eruptive size classes) dominates over intra-class size variability (i.e. size difference within an eruptive size class), the latter of which is treated as negligible. So far, no quantitative study has been undertaken to verify such an assumption. Here, we adopt a novel Probabilistic Volcanic Hazard Analysis (PVHA) strategy, which accounts for intrinsic eruptive variabilities, to quantify the tephra fallout hazard in the Campania area. We compare the results of the new probabilistic approach with the classical scenario approach. The results allow for determining whether a simplified scenario approach can be considered valid, and for quantifying the bias which arises when full variability is not accounted for. PMID:27067389

Small Class Size and Its Effects.

ERIC Educational Resources Information Center

Biddle, Bruce J.; Berliner, David C.

2002-01-01

Describes several prominent early grades small-class-size projects and their effects on student achievement: Indiana's Project Prime Time, Tennessee's Project STAR (Student/Teacher Achievement Ratio), Wisconsin's SAGE (Student Achievement Guarantee in Education) Program, and the California class-size-reduction program. Lists several conclusions,…

Cost-Effectiveness of Four Educational Interventions.

ERIC Educational Resources Information Center

Levin, Henry M.; And Others

This study employs meta-analysis and cost-effectiveness instruments to evaluate and compare cross-age tutoring, computer assistance, class size reductions, and instructional time increases for their utility in improving elementary school reading and math scores. Using intervention effect studies as replication models, researchers first estimate…

Class Size Reduction in California: Summary of the 1998-99 Evaluation Findings.

ERIC Educational Resources Information Center

Stecher, Brian M.; Bohrnstedt, George W.

This report discusses the results of the third year--1998-99--of California's Class Size Reduction (CSR) program. Assessments of the program show that CSR was almost fully implemented by 1998-99, with over 92 percent of students in K-3 in classes of 20 or fewer students. Those K-3 classes that had not been reduced in size were concentrated in…

OligoIS: Scalable Instance Selection for Class-Imbalanced Data Sets.

PubMed

García-Pedrajas, Nicolás; Perez-Rodríguez, Javier; de Haro-García, Aida

2013-02-01

In current research, an enormous amount of information is constantly being produced, which poses a challenge for data mining algorithms. Many of the problems in extremely active research areas, such as bioinformatics, security and intrusion detection, or text mining, share the following two features: large data sets and class-imbalanced distribution of samples. Although many methods have been proposed for dealing with class-imbalanced data sets, most of these methods are not scalable to the very large data sets common to those research fields. In this paper, we propose a new approach to dealing with the class-imbalance problem that is scalable to data sets with many millions of instances and hundreds of features. This proposal is based on the divide-and-conquer principle combined with application of the selection process to balanced subsets of the whole data set. This divide-and-conquer principle allows the execution of the algorithm in linear time. Furthermore, the proposed method is easy to implement using a parallel environment and can work without loading the whole data set into memory. Using 40 class-imbalanced medium-sized data sets, we will demonstrate our method's ability to improve the results of state-of-the-art instance selection methods for class-imbalanced data sets. Using three very large data sets, we will show the scalability of our proposal to millions of instances and hundreds of features.

Significance of microhabitat heterogeneity in the spatial pattern and size-class structure of Anastatica hierochuntica L.

NASA Astrophysics Data System (ADS)

Hegazy, Ahmad K.; Kabiel, Hanan F.

2007-05-01

Anastatica hierochuntica L. (Brassicaceae) is a desert monocarpic annual species characterized by a topochory/ombrohydrochory type of seed dispersal. The hygrochastic nature of the dry skeletons (dead individuals) permits controlling seed dispersal by rain events. The amount of dispersed seeds is proportional to the intensity of rainfall. When light showers occur, seeds are released and remain in the site. Seeds dispersed in the vicinity of the mother or source plant (primary type of seed dispersal) resulted in clumped pattern and complicated interrelationships among size-classes of the population. Following heavy rainfall, most seeds are released and transported into small patches and shallow depressions which collect runoff water. The dead A. hierochuntica skeletons demonstrate site-dependent size-class structure, spatial pattern and spatial interrelationships in different microhabitats. Four microhabitat types have been sampled: runnels, patches and simple and compound depressions in two sites (gravel and sand). Ripley's K-function was used to analyze the spatial pattern in populations of A. hierochuntica skeletons in the study microhabitats. Clumped patterns were observed in nearly all of the study microhabitats. Populations of A. hierochuntica in the sand site were more productive than in the gravel site and usually had more individuals in the larger size-classes. In the compound-depression microhabitat, the degree of clumping decreased from the core zone to the intermediate zone then shifted into overdispersed pattern in the outer zone. At the within size-class level, the clumped pattern dominated in small size classes but shifted into random and overdispersed patterns in the larger size classes. Aggregation between small and large size-classes was not well-defined but large individuals were found closer to the smaller individuals than to those of their own class. In relation to the phytomass and the size-class structure, the outer zone of the simple depression and the outer and intermediate zones of the compound depression microhabitats were the most productive sites.

76 FR 59116 - Procurement List; Additions

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-23

... NSN: AF110--Shirt, Class A/Primary Duty, USAF, Men's, Long Sleeve, Dark Navy Blue, Numerous Sizes. NSN: AF111--Shirt, Class A/Primary Duty, USAF, Women's, Long Sleeve, Dark Navy Blue, Numerous Sizes. NSN: AF120--Shirt, Class A/Primary Duty, USAF, Men's, Short Sleeve, Dark Navy Blue, Numerous Sizes. NSN...

Class Size, Academic Achievement and Public Policy.

ERIC Educational Resources Information Center

Ziegler, Suzanne

1997-01-01

This report addresses some of the concerns surrounding smaller classes and looks at whether reduced class sizes result in higher achievement levels, and concludes that it in fact does increase student achievement, so long as classes do not exceed 17 students. But many critics question whether the high cost of reducing classes to 17 or fewer…

Analysis of spatial distribution of land cover maps accuracy

NASA Astrophysics Data System (ADS)

Khatami, R.; Mountrakis, G.; Stehman, S. V.

2017-12-01

Land cover maps have become one of the most important products of remote sensing science. However, classification errors will exist in any classified map and affect the reliability of subsequent map usage. Moreover, classification accuracy often varies over different regions of a classified map. These variations of accuracy will affect the reliability of subsequent analyses of different regions based on the classified maps. The traditional approach of map accuracy assessment based on an error matrix does not capture the spatial variation in classification accuracy. Here, per-pixel accuracy prediction methods are proposed based on interpolating accuracy values from a test sample to produce wall-to-wall accuracy maps. Different accuracy prediction methods were developed based on four factors: predictive domain (spatial versus spectral), interpolation function (constant, linear, Gaussian, and logistic), incorporation of class information (interpolating each class separately versus grouping them together), and sample size. Incorporation of spectral domain as explanatory feature spaces of classification accuracy interpolation was done for the first time in this research. Performance of the prediction methods was evaluated using 26 test blocks, with 10 km × 10 km dimensions, dispersed throughout the United States. The performance of the predictions was evaluated using the area under the curve (AUC) of the receiver operating characteristic. Relative to existing accuracy prediction methods, our proposed methods resulted in improvements of AUC of 0.15 or greater. Evaluation of the four factors comprising the accuracy prediction methods demonstrated that: i) interpolations should be done separately for each class instead of grouping all classes together; ii) if an all-classes approach is used, the spectral domain will result in substantially greater AUC than the spatial domain; iii) for the smaller sample size and per-class predictions, the spectral and spatial domain yielded similar AUC; iv) for the larger sample size (i.e., very dense spatial sample) and per-class predictions, the spatial domain yielded larger AUC; v) increasing the sample size improved accuracy predictions with a greater benefit accruing to the spatial domain; and vi) the function used for interpolation had the smallest effect on AUC.

[Nitrogen Fraction Distributions and Impacts on Soil Nitrogen Mineralization in Different Vegetation Restorations of Karst Rocky Desertification].

PubMed

Hu, Ning; Ma, Zhi-min; Lan, Jia-cheng; Wu, Yu-chun; Chen, Gao-qi; Fu, Wa-li; Wen, Zhi-lin; Wang, Wen-jing

2015-09-01

In order to illuminate the impact on soil nitrogen accumulation and supply in karst rocky desertification area, the distribution characteristics of soil nitrogen pool for each class of soil aggregates and the relationship between aggregates nitrogen pool and soil nitrogen mineralization were analyzed in this study. The results showed that the content of total nitrogen, light fraction nitrogen, available nitrogen and mineral nitrogen in soil aggregates had an increasing tendency along with the descending of aggregate-size, and the highest content was occurred in < 0. 25 mm. The content of nitrogen fractions for all aggregate-classes followed in the order of abandoned land < grass land < brush land < brush-arbor land < arbor land in different sample plots. Artificial forest lands had more effects on the improvement of the soil nitrogen than honeysuckle land. In this study it also showed the nitrogen stockpiling quantity of each aggregate-size class was differed in all aggregate-size classes, in which the content of nitrogen fraction in 5-10 mm and 2-5 mm classes of soil aggregate-size were the highest. And it meant that soil nutrient mainly was stored in large size aggregates. Large size aggregates were significant to the storage of soil nutrient. For each class of soil aggregate-size, the contribution of the nitrogen stockpiling quantity of 0. 25-1 mm class to soil net nitrogen mineralization quantity was the biggest, and following >5mm and 2-5 mm classes, and the others were the smallest. With the positive vegetation succession, the weight percentage of > 5 mm aggregate-size classes was improved and the nitrogen storage of macro-aggregates also was increased. Accordingly, the capacity of soil supply mineral nitrogen and storage organic nitrogen were intensified.

Embodiment of social roles and thinness as a form of capital: A qualitative approach towards understanding female obesity disparities in Chile.

PubMed

Robinovich, Jossiana; Ossa, Ximena; Baeza, Bernardita; Krumeich, Anja; van der Borne, Bart

2018-03-01

Obesity in Chile disproportionately affects women of low socioeconomic status (SES). Research has shown that ideals of body size and differences in perceived social pressure for being slim across socioeconomic strata contribute to the social stratification of body size among women in modern societies. Thinness is most valued by high SES women, following western standards of ideal body size. Aiming to understand the link between ideals of body size and SES, this qualitative study explored how 36 Chilean women construct their bodily ideals according to their social position. A purposive sample of women with different profiles with regard to educational attainment, nutritional status and body size (dis)satisfaction was defined, aiming to cover a diverse spectrum of bodily perceptions. Data were collected through semi-structured interviews and approached through a thematic and narrative analysis. Drawing on Bourdieu's concepts of habitus, field, capital and embodiment of the social context, this study explains how ideals of body size and appearance are strongly linked to class-dependent gender roles and social roles. The existing gender and class inequalities in the Chilean social structure have been literally embodied by these women through a 'gendered class habitus'. Compliance with the thin ideal confers women different degrees of power according to their social position in different fields, such as in marriage and on the labour market, which turns thinness into an embodied form of capital. The societal dynamic behind obesity rates cannot be disregarded when approaching possible solutions. Promoting obesity-related lifestyle modification at an individual level might appear an over-simplistic and individualistic approach to a complex social issue. Context-oriented interventions that take cultural constructions of gender and social class into account might yield better results in the long term, while advocating for a more equitable society and social justice as a public health concern. Copyright © 2018 Elsevier Ltd. All rights reserved.

A Machine Learning and Cross-Validation Approach for the Discrimination of Vegetation Physiognomic Types Using Satellite Based Multispectral and Multitemporal Data.

PubMed

Sharma, Ram C; Hara, Keitarou; Hirayama, Hidetake

2017-01-01

This paper presents the performance and evaluation of a number of machine learning classifiers for the discrimination between the vegetation physiognomic classes using the satellite based time-series of the surface reflectance data. Discrimination of six vegetation physiognomic classes, Evergreen Coniferous Forest, Evergreen Broadleaf Forest, Deciduous Coniferous Forest, Deciduous Broadleaf Forest, Shrubs, and Herbs, was dealt with in the research. Rich-feature data were prepared from time-series of the satellite data for the discrimination and cross-validation of the vegetation physiognomic types using machine learning approach. A set of machine learning experiments comprised of a number of supervised classifiers with different model parameters was conducted to assess how the discrimination of vegetation physiognomic classes varies with classifiers, input features, and ground truth data size. The performance of each experiment was evaluated by using the 10-fold cross-validation method. Experiment using the Random Forests classifier provided highest overall accuracy (0.81) and kappa coefficient (0.78). However, accuracy metrics did not vary much with experiments. Accuracy metrics were found to be very sensitive to input features and size of ground truth data. The results obtained in the research are expected to be useful for improving the vegetation physiognomic mapping in Japan.

Cognitive Invariants of Geographic Event Conceptualization: What Matters and What Refines?

NASA Astrophysics Data System (ADS)

Klippel, Alexander; Li, Rui; Hardisty, Frank; Weaver, Chris

Behavioral experiments addressing the conceptualization of geographic events are few and far between. Our research seeks to address this deficiency by developing an experimental framework on the conceptualization of movement patterns. In this paper, we report on a critical experiment that is designed to shed light on the question of cognitively salient invariants in such conceptualization. Invariants have been identified as being critical to human information processing, particularly for the processing of dynamic information. In our experiment, we systematically address cognitive invariants of one class of geographic events: single entity movement patterns. To this end, we designed 72 animated icons that depict the movement patterns of hurricanes around two invariants: size difference and topological equivalence class movement patterns endpoints. While the endpoint hypothesis, put forth by Regier (2007), claims a particular focus of human cognition to ending relations of events, other research suggests that simplicity principles guide categorization and, additionally, that static information is easier to process than dynamic information. Our experiments show a clear picture: Size matters. Nonetheless, we also find categorization behaviors consistent with experiments in both the spatial and temporal domain, namely that topology refines these behaviors and that topological equivalence classes are categorized consistently. These results are critical steppingstones in validating spatial formalism from a cognitive perspective and cognitively grounding work on ontologies.

Measuring case-mix complexity of tertiary care hospitals using DRGs.

PubMed

Park, Hayoung; Shin, Youngsoo

2004-02-01

The objectives of the study were to develop a model that measures and evaluates case-mix complexity of tertiary care hospitals, and to examine the characteristics of such a model. Physician panels defined three classes of case complexity and assigned disease categories represented by Adjacent Diagnosis Related Groups (ADRGs) to one of three case complexity classes. Three types of scores, indicating proportions of inpatients in each case complexity class standardized by the proportions at the national level, were defined to measure the case-mix complexity of a hospital. Discharge information for about 10% of inpatient episodes at 85 hospitals with bed size larger than 400 and their input structure and research and education activity were used to evaluate the case-mix complexity model. Results show its power to predict hospitals with the expected functions of tertiary care hospitals, i.e. resource intensive care, expensive input structure, and high levels of research and education activities.

A Meta-Analysis of Class Sizes and Ratios in Early Childhood Education Programs: Are Thresholds of Quality Associated with Greater Impacts on Cognitive, Achievement, and Socioemotional Outcomes?

ERIC Educational Resources Information Center

Bowne, Jocelyn Bonnes; Magnuson, Katherine A.; Schindler, Holly S.; Duncan, Greg J.; Yoshikawa, Hirokazu

2017-01-01

This study uses data from a comprehensive database of U.S. early childhood education program evaluations published between 1960 and 2007 to evaluate the relationship between class size, child-teacher ratio, and program effect sizes for cognitive, achievement, and socioemotional outcomes. Both class size and child-teacher ratio showed nonlinear…

Class Size: A Battle between Accountability and Quality Instruction

ERIC Educational Resources Information Center

Januszka, Cynthia; Dixon-Krauss, Lisbeth

2008-01-01

A substantial amount of controversy surrounds the issue of class size in public schools. Parents and teachers are on one side, touting the benefits of smaller class sizes (e.g., increased academic achievement, greater student-teacher interaction, utilization of more innovative teaching strategies, and a decrease in discipline problems). On the…

Class Size Reduction and Academic Achievement of Low-Socioeconomic Students

ERIC Educational Resources Information Center

Rollins, Sarah E.

2013-01-01

Concern about the academic and social well-being of public education in the United States has been at the forefront of education reform. Increased class sizes, amended curriculum standards, and accountability standards have guided the way toward ways to reduce class sizes to meet the demands put upon educators. This study investigated the…

The Effects of Videoconferencing, Class Size, and Learner Characteristics on Training Outcomes

ERIC Educational Resources Information Center

Brown, Kenneth G.; Rietz, Thomas A.; Sugrue, Brenda

2005-01-01

We examined direct and interaction effects of learners' characteristics (cognitive ability, prior knowledge, prior experience, and motivation to learn) and classroom characteristics (videoconferencing and class size) on learning from a 16-week course. A 2x2 quasi-experimental design varied the class size between large (approximately 60 students)…

Biomass and productivity of three phytoplankton size classes in San Francisco Bay.

USGS Publications Warehouse

Cole, B.E.; Cloern, J.E.; Alpine, A.E.

1986-01-01

The 5-22 mu m size accounted for 40-50% of annual production in each embayment, but production by phytoplanton >22 mu m ranged from 26% in the S reach to 54% of total phytoplankton production in the landward embayment of the N reach. A productivity index is derived that predicts daily productivity for each size class as a function of ambient irradiance and integrated chlorophyll a in the photic zone. For the whole phytoplankton community and for each size class, this index was constant at approx= 0.76 g C m-2 (g chlorophyll a Einstein)-1. The annual means of maximum carbon assimilation numbers were usually similar for the three size classes. Spatial and temporal variations in size-fractionated productivity are primarily due to differences in biomass rather than size-dependent carbon assimilation rates. -from Authors

Classification of video sequences into chosen generalized use classes of target size and lighting level.

PubMed

Leszczuk, Mikołaj; Dudek, Łukasz; Witkowski, Marcin

The VQiPS (Video Quality in Public Safety) Working Group, supported by the U.S. Department of Homeland Security, has been developing a user guide for public safety video applications. According to VQiPS, five parameters have particular importance influencing the ability to achieve a recognition task. They are: usage time-frame, discrimination level, target size, lighting level, and level of motion. These parameters form what are referred to as Generalized Use Classes (GUCs). The aim of our research was to develop algorithms that would automatically assist classification of input sequences into one of the GUCs. Target size and lighting level parameters were approached. The experiment described reveals the experts' ambiguity and hesitation during the manual target size determination process. However, the automatic methods developed for target size classification make it possible to determine GUC parameters with 70 % compliance to the end-users' opinion. Lighting levels of the entire sequence can be classified with an efficiency reaching 93 %. To make the algorithms available for use, a test application has been developed. It is able to process video files and display classification results, the user interface being very simple and requiring only minimal user interaction.

The effects of overwinter flowson the spring condition of rainbow and brown trout size classes in the Green River downstream of Flaming Gorge Dam, Utah.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magnusson, A. K.; LaGory, K. E.; Hayse, J. W.

2010-06-25

Flaming Gorge Dam, a hydroelectric facility operated by the Bureau of Reclamation (Reclamation), is located on the Green River in Daggett County, northeastern Utah. Until recently, and since the early 1990s, single daily peak releases or steady flows have been the operational pattern of the dam during the winter period. However, releases from Flaming Gorge Reservoir followed a double-peak pattern (two daily flow peaks) during the winters of 2006-2007 and 2008-2009. Because there is little recent long-term history of double-peaking at Flaming Gorge Dam, the potential effects of double-peaking operations on trout body condition in the dam's tailwater are notmore » known. A study plan was developed that identified research activities to evaluate potential effects from winter double-peaking operations (Hayse et al. 2009). Along with other tasks, the study plan identified the need to conduct a statistical analysis of historical trout condition and macroinvertebrate abundance to evaluate the potential effects of hydropower operations. The results from analyses based on the combined size classes of trout (85-630 mm) were presented in Magnusson et al. (2008). The results of this earlier analysis suggested possible relationships between trout condition and flow, but concern that some of the relationships resulted from size-based effects (e.g., apparent changes in condition may have been related to concomitant changes in size distribution, because small trout may have responded differently to flow than large trout) prompted additional analysis of within-size class relationships. This report presents the results of analyses of three different size classes of trout (small: 200-299 mm, medium: 300-399 mm, and large: {ge}400 mm body length). We analyzed historical data to (1) describe temporal patterns and relationships among flows, benthic macroinvertebrate abundance, and condition of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in the tailwaters of Flaming Gorge Dam, and to (2) evaluate the relative importance of the effects of flow (i.e., flow volumes and flow variability), trout abundance (catch per unit effort [CPUE]), and benthic macroinvertebrate abundance on trout condition for different size classes of trout.« less

Exploring the full natural variability of eruption sizes within probabilistic hazard assessment of tephra dispersal

NASA Astrophysics Data System (ADS)

Selva, Jacopo; Sandri, Laura; Costa, Antonio; Tonini, Roberto; Folch, Arnau; Macedonio, Giovanni

2014-05-01

The intrinsic uncertainty and variability associated to the size of next eruption strongly affects short to long-term tephra hazard assessment. Often, emergency plans are established accounting for the effects of one or a few representative scenarios (meant as a specific combination of eruptive size and vent position), selected with subjective criteria. On the other hand, probabilistic hazard assessments (PHA) consistently explore the natural variability of such scenarios. PHA for tephra dispersal needs the definition of eruptive scenarios (usually by grouping possible eruption sizes and vent positions in classes) with associated probabilities, a meteorological dataset covering a representative time period, and a tephra dispersal model. PHA results from combining simulations considering different volcanological and meteorological conditions through a weight given by their specific probability of occurrence. However, volcanological parameters, such as erupted mass, eruption column height and duration, bulk granulometry, fraction of aggregates, typically encompass a wide range of values. Because of such a variability, single representative scenarios or size classes cannot be adequately defined using single values for the volcanological inputs. Here we propose a method that accounts for this within-size-class variability in the framework of Event Trees. The variability of each parameter is modeled with specific Probability Density Functions, and meteorological and volcanological inputs are chosen by using a stratified sampling method. This procedure allows avoiding the bias introduced by selecting single representative scenarios and thus neglecting most of the intrinsic eruptive variability. When considering within-size-class variability, attention must be paid to appropriately weight events falling within the same size class. While a uniform weight to all the events belonging to a size class is the most straightforward idea, this implies a strong dependence on the thresholds dividing classes: under this choice, the largest event of a size class has a much larger weight than the smallest event of the subsequent size class. In order to overcome this problem, in this study, we propose an innovative solution able to smoothly link the weight variability within each size class to the variability among the size classes through a common power law, and, simultaneously, respect the probability of different size classes conditional to the occurrence of an eruption. Embedding this procedure into the Bayesian Event Tree scheme enables for tephra fall PHA, quantified through hazard curves and maps representing readable results applicable in planning risk mitigation actions, and for the quantification of its epistemic uncertainties. As examples, we analyze long-term tephra fall PHA at Vesuvius and Campi Flegrei. We integrate two tephra dispersal models (the analytical HAZMAP and the numerical FALL3D) into BET_VH. The ECMWF reanalysis dataset are used for exploring different meteorological conditions. The results obtained clearly show that PHA accounting for the whole natural variability significantly differs from that based on a representative scenarios, as in volcanic hazard common practice.

Working with Large Class Size: Dispositions of Early Childhood Teachers in India

ERIC Educational Resources Information Center

Gupta, Amita

2004-01-01

Using sociocultural-historical constructivism, and post-colonial theory, the author conducted a study to examine, through the perceptions of teachers, school principals, and teacher educators, the relationship between the preparation and practice of early childhood teachers in private schools in New Delhi, India. The research questions…

GENETIC DIVERSITY AMONG POPULATIONS AND SIZE CLASSES OF BUCKEYES (AESCULUS: HIPPOCASTANACEAE) EXAMINED WITH MULTILOCUS VNTR PROBES. (R826602)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

The Impact of Brain-Based Strategies: One School's Perspective

ERIC Educational Resources Information Center

Hodges, Jane Allen

2013-01-01

Research has shown student inattention, off-task behaviors, and lack of listening skills in the classroom can impact progress in reading, math, and language development. Lack of verbal interaction in home environments, variations in learning and teaching modalities, and larger class sizes contribute to the difficulties students have in developing…

76 FR 27372 - Small Business Size Standards: Waiver of the Nonmanufacturer Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-11

... market research using the Dynamic Small Business Search (DSBS) database and no small business... no small business manufacturers or processors available to participate in the Federal market. In order to be considered available to participate in the Federal market for a class of products, a small...

The Relationship between Preschool Programming and School Readiness for Rural Children Entering Kindergarten

ERIC Educational Resources Information Center

Conway, Donna M.

2010-01-01

Children in the researcher's rural school district have limited opportunities for a high quality preschool programming that prepares them for school readiness. Quality preschool programming is defined as teachers with proper qualifications and training, small class size, stimulating curriculum, and parent involvement. The theoretical foundation…

The CEIC Review, 2001. A Catalyst for Merging Research, Policy, and Practice.

ERIC Educational Resources Information Center

Hartman, Bonnie, Ed.; Rohland, Mark, Ed.

2001-01-01

These three volumes contain articles related to (1) improving educational productivity (lessons from economics); (2) school-to-work (STW); and (3) reduced class size, offering recommendations from national invitational conferences. Topics include making schools work; tax revolts and school performance; market pressure and the impact on…

Polymorphic mountain whitefish (Prosopium williamsoni) in a coastal riverscape: size class assemblages, distribution, and habitat associations

USGS Publications Warehouse

Starr, James C.; Torgersen, Christian E.

2015-01-01

We compared the assemblage structure, spatial distributions, and habitat associations of mountain whitefish (Prosopium williamsoni) morphotypes and size classes. We hypothesised that morphotypes would have different spatial distributions and would be associated with different habitat features based on feeding behaviour and diet. Spatially continuous sampling was conducted over a broad extent (29 km) in the Calawah River, WA (USA). Whitefish were enumerated via snorkelling in three size classes: small (10–29 cm), medium (30–49 cm), and large (≥50 cm). We identified morphotypes based on head and snout morphology: a pinocchio form that had an elongated snout and a normal form with a blunted snout. Large size classes of both morphotypes were distributed downstream of small and medium size classes, and normal whitefish were distributed downstream of pinocchio whitefish. Ordination of whitefish assemblages with nonmetric multidimensional scaling revealed that normal whitefish size classes were associated with higher gradient and depth, whereas pinocchio whitefish size classes were positively associated with pool area, distance upstream, and depth. Reach-scale generalised additive models indicated that normal whitefish relative density was associated with larger substrate size in downstream reaches (R2 = 0.64), and pinocchio whitefish were associated with greater stream depth in the reaches farther upstream (R2 = 0.87). These results suggest broad-scale spatial segregation (1–10 km), particularly between larger and more phenotypically extreme individuals. These results provide the first perspective on spatial distributions and habitat relationships of polymorphic mountain whitefish.

Class Size Reduction in Practice: Investigating the Influence of the Elementary School Principal

ERIC Educational Resources Information Center

Burch, Patricia; Theoharis, George; Rauscher, Erica

2010-01-01

Class size reduction (CSR) has emerged as a very popular, if not highly controversial, policy approach for reducing the achievement gap. This article reports on findings from an implementation study of class size reduction policy in Wisconsin entitled the Student Achievement Guarantee in Education (SAGE). Drawing on case studies of nine schools,…

Teacher/Student Interactions in Public Elementary Schools When Class Size is a Factor.

ERIC Educational Resources Information Center

Krieger, Jean D.

This report describes a study designed to discover the nature of teacher-student interactions in regular-size classes with 25 or more students and small-size classes with fewer than 18 students. Eleven public-school primary classrooms were observed, and the interactions between the teachers and students were studied. Verbal and nonverbal…

Serendipitous Policy Implications from Class-Size-Initiated Inquiry: IAQ?

ERIC Educational Resources Information Center

Achilles, C. M.; Prout, Jean; Finn, J. D.; Bobbett, Gordon C.

The level of carbon dioxide in a classroom can have a significant negative effect on teaching and learning. Carbon dioxide (CO2) level is affected by class size and time of day. Six urban schools were studied to characterize the effects of these three factors on different class sizes. Carbon monoxide, CO2, temperature, and relative humidity…

The Cost of Class Size Reduction: Advice for Policymakers. RAND Graduate School Dissertation.

ERIC Educational Resources Information Center

Reichardt, Robert E.

This dissertation provides information to state-level policymakers that will help them avoid two implementation problems seen in the past in California's class-size-reduction (CSR) reform. The first problem was that flat, per student reimbursement did not adequately cover costs in districts with larger pre-CSR class-sizes or smaller schools. The…

Size Matters. The Relevance and Hicksian Surplus of Preferred College Class Size

ERIC Educational Resources Information Center

Mandel, Philipp; Susmuth, Bernd

2011-01-01

The contribution of this paper is twofold. First, we examine the impact of class size on student evaluations of instructor performance using a sample of approximately 1400 economics classes held at the University of Munich from Fall 1998 to Summer 2007. We offer confirmatory evidence for the recent finding of a large, highly significant, and…

Class Size and Language Learning in Hong Kong: The Students' Perspective

ERIC Educational Resources Information Center

Harfitt, Gary James

2012-01-01

Background: There is currently ongoing debate in Hong Kong between the teachers' union and the Government on the reduction of large class size (typically more than 40 students) in secondary schools and whether smaller class sizes might facilitate improvements in teaching and learning. In fact, many Hong Kong secondary schools have already started…

Does Class Size in First Grade Relate to Children's Academic and Social Performance or Observed Classroom Processes?

ERIC Educational Resources Information Center

Allhusen, Virginia; Belsky, Jay; Booth-LaForce, Cathryn L.; Bradley, Robert; Brownwell, Celia A; Burchinal, Margaret; Campbell, Susan B.; Clarke-Stewart, K. Alison; Cox, Martha; Friedman, Sarah L.; Hirsh-Pasek, Kathryn; Houts, Renate M.; Huston, Aletha; Jaeger, Elizabeth; Johnson, Deborah J.; Kelly, Jean F.; Knoke, Bonnie; Marshall, Nancy; McCartney, Kathleen; Morrison, Frederick J.; O'Brien, Marion; Tresch Owen, Margaret; Payne, Chris; Phillips, Deborah; Pianta, Robert; Randolph, Suzanne M.; Robeson, Wendy W.; Spieker, Susan; Lowe Vandell, Deborah; Weinraub, Marsha

2004-01-01

This study evaluated the extent to which first-grade class size predicted child outcomes and observed classroom processes for 651 children (in separate classrooms). Analyses examined observed child-adult ratios and teacher-reported class sizes. Smaller classrooms showed higher quality instructional and emotional support, although children were…

Class Size and Student Evaluations in Sweden

ERIC Educational Resources Information Center

Westerlund, Joakim

2008-01-01

This paper examines the effect of class size on student evaluations of the quality of an introductory mathematics course at Lund University in Sweden. In contrast to much other studies, we find a large negative, and statistically significant, effect of class size on the quality of the course. This result appears to be quite robust, as almost all…

The Effects of Class Size in Online College Courses: Experimental Evidence. CEPA Working Paper No. 15-14

ERIC Educational Resources Information Center

Bettinger, Eric; Doss, Christopher; Loeb, Susanna; Taylor, Eric

2015-01-01

Class size is a first-order consideration in the study of education production and education costs. How larger or smaller classes affect student outcomes is especially relevant to the growth and design of online classes. We study a field experiment in which college students were quasi-randomly assigned to either a large or a small class. All…

45 CFR 1306.32 - Center-based program option.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Center-based program option. (a) Class size. (1) Head Start classes must be staffed by a teacher and an aide or two teachers and, whenever possible, a volunteer. (2) Grantees must determine their class size based on the predominant age of the children who will participate in the class and whether or not a...

Modified centroid for estimating sand, silt, and clay from soil texture class

USDA-ARS?s Scientific Manuscript database

Models that require inputs of soil particle size commonly use soil texture class for input; however, texture classes do not represent the continuum of soil size fractions. Soil texture class and clay percentage are collected as a standard practice for many land management agencies (e.g., NRCS, BLM, ...

Special Education Program Standards Study. Commonwealth of Virginia. Final Technical Report.

ERIC Educational Resources Information Center

Keith, Timothy Z.; And Others

This federally funded study investigated Virginia special education program standards, focusing on local applications of the standards for class size and class mix and the effect of varying class size and class mix on student outcomes. The study concentrated on students with educable mental retardation, severe emotional disturbance, and specific…

The False Promise of Class-Size Reduction

ERIC Educational Resources Information Center

Chingos, Matthew M.

2011-01-01

Class-size reduction, or CSR, is enormously popular with parents, teachers, and the public in general. Many parents believe that their children will benefit from more individualized attention in a smaller class and many teachers find smaller classes easier to manage. The pupil-teacher ratio is an easy statistic for the public to monitor as a…

46 CFR 56.30-10 - Flanged joints (modifies 104.5.1(a)).

Code of Federal Regulations, 2013 CFR

2013-10-01

... addition of a strength fillet weld of the size as shown, may be used in Class I systems not exceeding 750... buttwelding flanges must be provided. For Class II piping systems, the size of the strength fillet may be... void spaces is desirable. For systems of Class II, the size of the strength fillet may be limited to a...

46 CFR 56.30-10 - Flanged joints (modifies 104.5.1(a)).

Code of Federal Regulations, 2014 CFR

2014-10-01

... addition of a strength fillet weld of the size as shown, may be used in Class I systems not exceeding 750... buttwelding flanges must be provided. For Class II piping systems, the size of the strength fillet may be... void spaces is desirable. For systems of Class II, the size of the strength fillet may be limited to a...

46 CFR 56.30-10 - Flanged joints (modifies 104.5.1(a)).

Code of Federal Regulations, 2012 CFR

2012-10-01

... addition of a strength fillet weld of the size as shown, may be used in Class I systems not exceeding 750... buttwelding flanges must be provided. For Class II piping systems, the size of the strength fillet may be... void spaces is desirable. For systems of Class II, the size of the strength fillet may be limited to a...

Teacher Aides, Class Size and Academic Achievement: A Preliminary Evaluation of Indiana's Prime Time.

ERIC Educational Resources Information Center

Lapsley, Daniel K.; Daytner, Katrina M.; Kelly, Ken; Maxwell, Scott E.

This large-scale evaluation of Indiana's Prime Time, a funding mechanism designed to reduce class size or pupil-teacher ratio (PTR) in grades K-3 examined the academic performance of nearly 11,000 randomly selected third graders on the state mandated standardized achievement test as a function of class size, PTR, and presence of an instructional…

The Impact of a Universal Class-Size Reduction Policy: Evidence from Florida's Statewide Mandate

ERIC Educational Resources Information Center

Chingos, Matthew M.

2012-01-01

Class-size reduction (CSR) mandates presuppose that resources provided to reduce class size will have a larger impact on student outcomes than resources that districts can spend as they see fit. I estimate the impact of Florida's statewide CSR policy by comparing the deviations from prior achievement trends in districts that were required to…

Class Size and Sorting in Market Equilibrium: Theory and Evidence. NBER Working Paper No. 13303

ERIC Educational Resources Information Center

Urquiola, Miguel; Verhoogen, Eric

2007-01-01

This paper examines how schools choose class size and how households sort in response to those choices. Focusing on the highly liberalized Chilean education market, we develop a model in which schools are heterogeneous in an underlying productivity parameter, class size is a component of school quality, households are heterogeneous in income and…

Reducing Class Size: A Smart Way To Improve America's Urban Schools. Second Edition.

ERIC Educational Resources Information Center

Naik, Manish; Casserly, Michael; Uro, Gabriela

The Council of the Great City Schools, a coalition of the largest urban public schools in the United States, surveyed its membership to determine how they were using federal class size reduction funds in the 2000-2001 school year. Thirty-six major urban school systems responded. Results indicate that the federal class size reduction program is…

Microcystin distribution in physical size class separations of natural plankton communities

USGS Publications Warehouse

Graham, J.L.; Jones, J.R.

2007-01-01

Phytoplankton communities in 30 northern Missouri and Iowa lakes were physically separated into 5 size classes (>100 ??m, 53-100 ??m, 35-53 ??m, 10-35 ??m, 1-10 ??m) during 15-21 August 2004 to determine the distribution of microcystin (MC) in size fractionated lake samples and assess how net collections influence estimates of MC concentration. MC was detected in whole water (total) from 83% of takes sampled, and total MC values ranged from 0.1-7.0 ??g/L (mean = 0.8 ??g/L). On average, MC in the > 100 ??m size class comprised ???40% of total MC, while other individual size classes contributed 9-20% to total MC. MC values decreased with size class and were significantly greater in the >100 ??m size class (mean = 0.5 ??g /L) than the 35-53 ??m (mean = 0.1 ??g/L), 10-35 ??m (mean = 0.0 ??g/L), and 1-10 ??m (mean = 0.0 ??g/L) size classes (p < 0.01). MC values in nets with 100-??m, 53-??m, 35-??m, and 10-??m mesh were cumulatively summed to simulate the potential bias of measuring MC with various size plankton nets. On average, a 100-??m net underestimated total MC by 51%, compared to 37% for a 53-??m net, 28% for a 35-??m net, and 17% for a 10-??m net. While plankton nets consistently underestimated total MC, concentration of algae with net sieves allowed detection of MC at low levels (???0.01 ??/L); 93% of lakes had detectable levels of MC in concentrated samples. Thus, small mesh plankton nets are an option for documenting MC occurrence, but whole water samples should be collected to characterize total MC concentrations. ?? Copyright by the North American Lake Management Society 2007.

Are wildlife detector dogs or people better at finding Desert Tortoises (Gopherus agassizii)?

USGS Publications Warehouse

Nussear, K.E.; Esque, T.C.; Heaton, J.S.; Cablk, Mary E.; Drake, K.K.; Valentin, C.; Yee, J.L.; Medica, P.A.

2008-01-01

Our ability to study threatened and endangered species depends on locating them readily in the field. Recent studies highlight the effectiveness of trained detector dogs to locate wildlife during field surveys, including Desert Tortoises in a semi-natural setting. Desert Tortoises (Gopherus agassizii) are cryptic and difficult to detect during surveys, especially the smaller size classes. We conducted comparative surveys to determine whether human or detector dog teams were more effective at locating Desert Tortoises in the wild. We compared detectability of Desert Tortoises and the costs to deploy human and dog search teams. Detectability of tortoises was not statistically different for either team, and was estimated to be approximately 70% (SE = 5%). Dogs found a greater proportion of tortoises located in vegetation than did humans. The dog teams finished surveys 2.5 hours faster than the humans on average each day. The human team cost was approximately $3,000 less per square kilometer sampled. Dog teams provided a quick and effective method for surveying for adult Desert Tortoises; however, we were unable to determine-their effectiveness at locating smaller size classes. Detection of smaller size classes during surveys would improve management of the species and should be addressed by future research using Desert Tortoise detector dogs.

Sensitivity of the simulation of tropical cyclone size to microphysics schemes

NASA Astrophysics Data System (ADS)

Chan, Kelvin T. F.; Chan, Johnny C. L.

2016-09-01

The sensitivity of the simulation of tropical cyclone (TC) size to microphysics schemes is studied using the Advanced Hurricane Weather Research and Forecasting Model (WRF). Six TCs during the 2013 western North Pacific typhoon season and three mainstream microphysics schemes-Ferrier (FER), WRF Single-Moment 5-class (WSM5) and WRF Single-Moment 6-class (WSM6)-are investigated. The results consistently show that the simulated TC track is not sensitive to the choice of microphysics scheme in the early simulation, especially in the open ocean. However, the sensitivity is much greater for TC intensity and inner-core size. The TC intensity and size simulated using the WSM5 and WSM6 schemes are respectively higher and larger than those using the FER scheme in general, which likely results from more diabatic heating being generated outside the eyewall in rainbands. More diabatic heating in rainbands gives higher inflow in the lower troposphere and higher outflow in the upper troposphere, with higher upward motion outside the eyewall. The lower-tropospheric inflow would transport absolute angular momentum inward to spin up tangential wind predominantly near the eyewall, leading to the increment in TC intensity and size (the inner-core size, especially). In addition, the inclusion of graupel microphysics processes (as in WSM6) may not have a significant impact on the simulation of TC track, intensity and size.

Social Class and Income Inequality in the United States: Ownership, Authority, and Personal Income Distribution from 1980 to 2010

PubMed Central

Wodtke, Geoffrey T.

2016-01-01

This study outlines a theory of social class based on workplace ownership and authority relations, and it investigates the link between social class and growth in personal income inequality since the 1980s. Inequality trends are governed by changes in between-class income differences, changes in the relative size of different classes, and changes in within-class income dispersion. Data from the General Social Survey are used to investigate each of these changes in turn and to evaluate their impact on growth in inequality at the population level. Results indicate that between-class income differences grew by about 60 percent since the 1980s and that the relative size of different classes remained fairly stable. A formal decomposition analysis indicates that changes in the relative size of different social classes had a small dampening effect and that growth in between-class income differences had a large inflationary effect on trends in personal income inequality. PMID:27087695

Social Class and Income Inequality in the United States: Ownership, Authority, and Personal Income Distribution from 1980 to 2010.

PubMed

Wodtke, Geoffrey T

2016-03-01

This study outlines a theory of social class based on workplace ownership and authority relations, and it investigates the link between social class and growth in personal income inequality since the 1980s. Inequality trends are governed by changes in between-class income differences, changes in the relative size of different classes, and changes in within-class income dispersion. Data from the General Social Survey are used to investigate each of these changes in turn and to evaluate their impact on growth in inequality at the population level. Results indicate that between-class income differences grew by about 60% since the 1980s and that the relative size of different classes remained fairly stable. A formal decomposition analysis indicates that changes in the relative size of different social classes had a small dampening effect and that growth in between-class income differences had a large inflationary effect on trends in personal income inequality.

Effects of Locus of Control, Academic Self-Efficacy, and Tutoring on Academic Performance

ERIC Educational Resources Information Center

Drago, Anthony; Rheinheimer, David C.; Detweiler, Thomas N.

2018-01-01

This study investigated the connection between locus of control (LOC), academic self-efficacy (ASE), and academic performance, and whether these variables are affected by tutoring. Additional variables of interest, including gender, students' Pell Grant status, ethnicity, and class size, were also considered for the research models. The population…

Meta-Analysis at Middle Age: A Personal History

ERIC Educational Resources Information Center

Glass, Gene V.

2015-01-01

The 40-year history of meta-analysis is traced from the vantage point of one of its originators. Research syntheses leading to the first examples of meta-analysis are identified. Early meta-analyses of the literature on psychotherapy outcomes and school class size are recounted. The influence on the development of meta-analysis of several…

EXTRACELLULAR ENZYME ACTIVITY IN A RIVER-BAY-SHELF TRANSECT: VARIATIONS IN POLYSACCHARIDE HYDROLYSIS RATES WITH SUBSTRATE AND SIZE CLASS. (R825159)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

A Qualitative Investigation of Student Outcomes in a Residential Learning Community

ERIC Educational Resources Information Center

Blackhurst, Anne E.; Akey, Lynn D.; Bobilya, Andrew J.

2003-01-01

Researchers conducted a qualitative study of students' in- and out-of-class experiences in a residential learning community at a mid-sized public institution. Focus group interviews were conducted to explore (a) the outcomes of learning community membership from participants' point of view and (b) the connections between participants' reported…

The Value of Oral Feedback in the Context of Capstone Projects in Design Education

ERIC Educational Resources Information Center

Karlsen, Kristine Hoeg

2017-01-01

Research frequently reports student dissatisfaction with feedback in higher education. Large class sizes and modularization challenge teachers in providing useful feedback. Most of these studies have investigated student perceptions of written feedback in coursework, and few attempts have been made considering feedback in face-to-face contexts…

Implications of "Dimensions of Quality" in a Market Environment. HEA Research Series

ERIC Educational Resources Information Center

Gibbs, Graham

2012-01-01

Do prospective students get the information they need to assess what can be gained from attending a particular higher education institution? Professor Gibbs' highly influential 2010 report, "Dimensions of Quality", found that student outcomes can be affected by the way that institutions choose to use available resources; class size, the…

A Standardized Mean Difference Effect Size for Multiple Baseline Designs across Individuals

ERIC Educational Resources Information Center

Hedges, Larry V.; Pustejovsky, James E.; Shadish, William R.

2013-01-01

Single-case designs are a class of research methods for evaluating treatment effects by measuring outcomes repeatedly over time while systematically introducing different condition (e.g., treatment and control) to the same individual. The designs are used across fields such as behavior analysis, clinical psychology, special education, and…

Finding the Right Mix: Teaching Methods as Predictors for Student Progress on Learning Objectives

ERIC Educational Resources Information Center

Glover, Jacob I.

2012-01-01

This study extends existing student ratings research by exploring how teaching methods, individually and collectively, influence a minimum standard of student achievement on learning objectives and how class size impacts this influence. Twenty teaching methods were used to predict substantial or exceptional progress on each of 12 learning…

Flow Injection Analysis and Liquid Chromatography for Multifunctional Chemical Analysis (MCA) Systems

ERIC Educational Resources Information Center

Mayo, Ana V.; Loegel, Thomas N.; Bretz, Stacey Lowery; Danielson, Neil D.

2013-01-01

The large class sizes of first-year chemistry labs makes it challenging to provide students with hands-on access to instrumentation because the number of students typically far exceeds the number of research-grade instruments available to collect data. Multifunctional chemical analysis (MCA) systems provide a viable alternative for large-scale…

Thin-plate spline analysis of craniofacial growth in Class I and Class II subjects.

PubMed

Franchi, Lorenzo; Baccetti, Tiziano; Stahl, Franka; McNamara, James A

2007-07-01

To compare the craniofacial growth characteristics of untreated subjects with Class II division 1 malocclusion with those of subjects with normal (Class I) occlusion from the prepubertal through the postpubertal stages of development. The Class II division 1 sample consisted of 17 subjects (11 boys and six girls). The Class I sample also consisted of 17 subjects (13 boys and four girls). Three craniofacial regions (cranial base, maxilla, and mandible) were analyzed on the lateral cephalograms of the subjects in both groups by means of thin-plate spline analysis at T1 (prepubertal) and T2 (postpubertal). Both cross-sectional and longitudinal comparisons were performed on both size and shape differences between the two groups. The results showed an increased cranial base angulation as a morphological feature of Class II malocclusion at the prepubertal developmental phase. Maxillary changes in either shape or size were not significant. Subjects with Class II malocclusion exhibited a significant deficiency in the size of the mandible at the completion of active craniofacial growth as compared with Class I subjects. A significant deficiency in the size of the mandible became apparent in Class II subjects during the circumpubertal period and it was still present at the completion of active craniofacial growth.

Protograph LDPC Codes Over Burst Erasure Channels

NASA Technical Reports Server (NTRS)

Divsalar, Dariush; Dolinar, Sam; Jones, Christopher

2006-01-01

In this paper we design high rate protograph based LDPC codes suitable for binary erasure channels. To simplify the encoder and decoder implementation for high data rate transmission, the structure of codes are based on protographs and circulants. These LDPC codes can improve data link and network layer protocols in support of communication networks. Two classes of codes were designed. One class is designed for large block sizes with an iterative decoding threshold that approaches capacity of binary erasure channels. The other class is designed for short block sizes based on maximizing minimum stopping set size. For high code rates and short blocks the second class outperforms the first class.

Class-Size Reduction Program Evaluation, 2001-02. A Report to the North Carolina Department of Public Instruction.

ERIC Educational Resources Information Center

Speas, Carol

In 2001-2002, 23 schools in the Wake County Public School System (WCPSS), North Carolina, were provided with 40 teacher positions through the Class Size Reduction Program (CSR). Achievement results for students in reduced class sizes were compared with those of similar students in other CSR schools who did not choose the same grade for the project…

Early Elementary Class-Size Reduction: A Neo-Institutional Analysis of the Social, Political, and Economic Influences on State-Level Policymaking.

ERIC Educational Resources Information Center

Mitchell, Ross E.

This paper examines the social, political, and economic factors that influenced the adoption and diffusion of early-elementary school class-size-reduction policies at the state level. It applies a neo-institutional framework to explain the rapid spread of class-size reduction policies throughout many state legislatures and boards of education. It…

77 FR 10724 - Western Pacific Pelagic Fisheries; American Samoa Longline Limited Entry Program

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-23

... size class falls below the maximum allowed. Six permits are available, as follows: Four in Class A (vessels less than or equal to 40 ft in overall length); and Two in Class D (over 70 ft in overall length... the highest priority to the applicant (for any vessel size class) with the earliest documented...

Effectiveness of the Size Matters Handwriting Program.

PubMed

Pfeiffer, Beth; Rai, Gillian; Murray, Tammy; Brusilovskiy, Eugene

2015-04-01

The purpose of the research was to study changes in handwriting legibility among kindergarten, first- and second-grade students in response to the Size Matters curricular-based handwriting program. A two-group pre-post-test design was implemented at two public schools with half of the classrooms assigned to receive the Size Matters program and the other continuing to receive standard instruction. All participants completed two standardized handwriting measures at pre-test and after 40 instructional sessions were completed with the classes receiving the handwriting program. Results identified significant changes in legibility in the handwriting intervention group for all three grades when compared with the standard instruction group. The results of this study support the use of a curricular-embedded handwriting program and provide the foundation for future research examining the impact of handwriting legibility on learning outcomes.

Single-case synthesis tools II: Comparing quantitative outcome measures.

PubMed

Zimmerman, Kathleen N; Pustejovsky, James E; Ledford, Jennifer R; Barton, Erin E; Severini, Katherine E; Lloyd, Blair P

2018-03-07

Varying methods for evaluating the outcomes of single case research designs (SCD) are currently used in reviews and meta-analyses of interventions. Quantitative effect size measures are often presented alongside visual analysis conclusions. Six measures across two classes-overlap measures (percentage non-overlapping data, improvement rate difference, and Tau) and parametric within-case effect sizes (standardized mean difference and log response ratio [increasing and decreasing])-were compared to determine if choice of synthesis method within and across classes impacts conclusions regarding effectiveness. The effectiveness of sensory-based interventions (SBI), a commonly used class of treatments for young children, was evaluated. Separately from evaluations of rigor and quality, authors evaluated behavior change between baseline and SBI conditions. SBI were unlikely to result in positive behavior change across all measures except IRD. However, subgroup analyses resulted in variable conclusions, indicating that the choice of measures for SCD meta-analyses can impact conclusions. Suggestions for using the log response ratio in SCD meta-analyses and considerations for understanding variability in SCD meta-analysis conclusions are discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Portable radiography: a reality and necessity for ISS and explorer-class missions.

PubMed

Lerner, David J; Parmet, Allen J

2015-02-01

On ISS missions and explorer class missions, unexpected medical and surgical emergencies could be disastrous. Lack of ability to rapidly assess and make critical decisions affects mission capability. Current imaging modalities on ISS consist only of ultrasound. There are many acute diagnoses which ultrasound alone cannot diagnose. Portable X-Ray imaging (radiography) technology has advanced far enough to where it is now small enough, cheap enough, and accurate enough to give diagnostic quality images sent wirelessly to the onboard computer and on Earth for interpretation while fitting in something the size of a briefcase. Although further research is warranted, Portable Radiography is an important addition to have on ISS and future Explorer Class Missions while maintaining a very small footprint.

The Implication of Large Class Size in the Teaching and Learning of Business Education in Tertiary Institution in Ekiti State

ERIC Educational Resources Information Center

Ayeni, Olapade Grace; Olowe, Modupe Oluwatoyin

2016-01-01

Large class size is one of the problems in the educational sector that developing nations have been grappling with. Nigeria as a developing nation is no exception. The purpose of this study is to provide views of both lecturers and students on large class size and how it affects teaching and learning in tertiary institutions in Ekiti State of…

Environmental influences and ontogenetic differences in vertical habitat use of black marlin (Istiompax indica) in the southwestern Pacific

PubMed Central

Tracey, Sean R.; Pepperell, Julian G.; Domeier, Michael L.; Bennett, Michael B.

2017-01-01

The black marlin (Istiompax indica) is a highly migratory billfish that occupies waters throughout the tropical and subtropical Indo-Pacific. To characterize the vertical habitat use of I. indica, we examined the temperature-depth profiles collected using 102 pop-up satellite archival tags deployed off the east coast of Australia. Modelling of environmental variables revealed location, sea-surface height deviation, mixed layer depth and dissolved oxygen to all be significant predictors of vertical habitat use. Distinct differences in diel movements were observed between the size classes, with larger size classes of marlin (greater than 50 kg) undertaking predictable bounce-diving activity during daylight hours, while diving behaviour of the smallest size class occurred randomly during both day and night. Overall, larger size classes of I. indica were found to use an increased thermal range and spend more time in waters below 150 m than fish of smaller size classes. The differences in the diving behaviour among size classes were suggested to reflect ontogenetic differences in foraging behaviour or physiology. The findings of this study demonstrate, for the first time to our knowledge, ontogenetic differences in vertical habitat in a species of billfish, and further the understanding of pelagic fish ecophysiology in the presence of global environmental change. PMID:29291060

Variations in tooth size and arch dimensions in Malay schoolchildren.

PubMed

Hussein, Khalid W; Rajion, Zainul A; Hassan, Rozita; Noor, Siti Noor Fazliah Mohd

2009-11-01

To compare the mesio-distal tooth sizes and dental arch dimensions in Malay boys and girls with Class I, Class II and Class III malocclusions. The dental casts of 150 subjects (78 boys, 72 girls), between 12 and 16 years of age, with Class I, Class II and Class III malocclusions were used. Each group consisted of 50 subjects. An electronic digital caliper was used to measure the mesio-distal tooth sizes of the upper and lower permanent teeth (first molar to first molar), the intercanine and intermolar widths. The arch lengths and arch perimeters were measured with AutoCAD software (Autodesk Inc., San Rafael, CA, U.S.A.). The mesio-distal dimensions of the upper lateral incisors and canines in the Class I malocclusion group were significantly smaller than the corresponding teeth in the Class III and Class II groups, respectively. The lower canines and first molars were significantly smaller in the Class I group than the corresponding teeth in the Class II group. The lower intercanine width was significantly smaller in the Class II group as compared with the Class I group, and the upper intermolar width was significantly larger in Class III group as compared with the Class II group. There were no significant differences in the arch perimeters or arch lengths. The boys had significantly wider teeth than the girls, except for the left lower second premolar. The boys also had larger upper and lower intermolar widths and lower intercanine width than the girls. Small, but statistically significant, differences in tooth sizes are not necessarily accompanied by significant arch width, arch length or arch perimeter differences. Generally, boys have wider teeth, larger lower intercanine width and upper and lower intermolar widths than girls.

Differentiated Instruction: Understanding the Personal Factors and Organizational Conditions that Facilitate Differentiated Instruction in Elementary Mathematics Classrooms

ERIC Educational Resources Information Center

Abbati, Diana Guglielmo

2012-01-01

Differentiated instruction is a widely held practice used by teachers to provide diverse learners with complex learning opportunities in the area of mathematics. Research on differentiated instruction shows a multitude of factors that support high quality instruction in mixed-ability elementary classrooms. These factors include small-class size,…

Evaluating Differences in Landscape Interpretation between Webcam and Field-Based Experiences

ERIC Educational Resources Information Center

Kolivras, Korine N.; Luebbering, Candice R.; Resler, Lynn M.

2012-01-01

Field trips have become less common due to issues including budget constraints and large class sizes. Research suggests that virtual field trips can substitute for field visits, but the role of webcams has not been evaluated. To investigate the potential for webcams to substitute for field trips, participants viewed urban and physical landscapes…

Renewable Fuels and Lubricants Laboratory | Transportation Research | NREL

Science.gov Websites

delivery vans to full-size buses and Class 8 tractors. Heavy-Duty and Light-Duty Engine Dynamometer Test Cells The ReFUEL Laboratory features two engine dynamometer test cells-one for heavy-duty (up to 600 hp the Heavy-Duty Federal Test Procedures (HD-FTP), are highly standardized, and results can be readily

Big Ideas behind Daily 5 and CAFE

ERIC Educational Resources Information Center

Boushey, Gail; Moser, Joan

2012-01-01

The Daily 5 and CAFE were born out of The Sister's research and observations of instructional mentors, their intense desire to be able to deliver highly intentional, focused instruction to small groups and individuals while the rest of the class was engaged in truly authentic reading and writing, and their understanding that a one size fits all…

Inquiry Learning: Level, Discipline, Class Size, What Matters?

ERIC Educational Resources Information Center

Vajoczki, Susan; Watt, Susan; Vine, Michelle M.; Liao, Xueqing

2011-01-01

Inquiry learning is a pedagogical approach that focuses on the processes and skills required to conduct research. It is a pedagogical approach that has been demonstrated to have positive learning outcomes. McMaster University has been committed to this form of learning for more than ten years in three of the faculties on campus (i.e., Humanities,…

Use of Facebook Group as Blended Learning and Learning Management System in Writing

ERIC Educational Resources Information Center

Tananuraksakul, Noparat

2014-01-01

In this paper, I will report qualitative research findings on how undergraduate students at a small-sized university in Thailand perceive Facebook group usage in a writing class. The findings suggest that the Facebook group can be used as blended learning (a hybrid instructional model) and learning management system (posting announcements and…

ePortfolios and Audience: Teaching a Critical Twenty-First Century Skill

ERIC Educational Resources Information Center

Gallagher, Chris W.; Poklop, Laurie L.

2014-01-01

This article reports on a three-year investigation into how and to what extent ePortfolios sponsor teacher and student learning about audience in first-year writing classes at a mid-sized research university. Through interviews with students and instructors and detailed analysis of students' ePortfolios, we found that, more often than not, the…

School Staffs Grew in New York Despite Falling Enrollment. Research Bulletin, No. 4

ERIC Educational Resources Information Center

McMahon, E.J.

2010-01-01

New York State educators are warning that proposed cuts in state aid to public schools next year could force more than 14,000 teacher layoffs. Officials of the state's largest teachers' union claim aid cuts will "devastate" education, leading to a "drastic" reduction of programs and "much larger class sizes." But…

Patching the Leaky STEM Pipeline: Identifying Institutional Factors That Influence a STEM Qualified Female Undergraduate s Choice of Institution

NASA Astrophysics Data System (ADS)

Hurlock, Ashley J.

Despite increased female participation in the workforce and females earning more undergraduate degrees than men over the past decade, women are still awarded fewer undergraduate degrees than men and hold less than 25% of jobs in the areas of science, technology, engineering and math, or STEM (Beede, et al., 2011). Research shows that females may be leaking from the STEM pipeline because they are not choosing to attend institutions that fulfill their interdisciplinary and non-academic interests or have learning environments that are supportive of their needs. The purpose of this quantitative, cross-sectional survey study, conducted at one non-research intensive university, was to identify institutional factors most pertinent to the decision to attend a non-research intensive university by a "STEM qualified" female undergraduate student. 23 of 45 factors were reported as positively influencing their decision regardless of major. The top six factors for both groups were: average class size, campus environment, a visit to campus, university population size, and major/department offered. The seven factors ranked statistically significantly different between STEM and non-STEM majors were undergraduate research opportunities, faculty reputation, graduate/professional school admission, academic support/tutoring, graduate program available, intramural sports, and off-campus housing. Only two of 17 factors negatively influenced STEM majors who were accepted to a research intensive university: the research intensive university's size and average class sizes were undesirable compared to their current institution. STEM qualified females weighed the importance of non-academic factors as high, or higher, than critical academic factors. STEM qualified females are also choosing to attend the non-research intensive university for a variety of reasons and not simply because another institution did not offer certain academic factors. Future studies should expanded to include other non-research intensive universities, research intensive universities, and high schools in order to further understand the impact that certain factors have on female choice of institution. The authors strongly feel that if institutions which provide a more supportive environment for female undergraduates create successful recruitment initiatives, their female students may be more likely to persist as STEM majors. This could potentially patch one of the substantial leaks in the STEM pipeline for women.

The Impact of a Universal Class-Size Reduction Policy: Evidence from Florida's Statewide Mandate. Program on Education Policy and Governance Working Papers Series. PEPG 10-03

ERIC Educational Resources Information Center

Chingos, Matthew M.

2010-01-01

Class-size reduction (CSR) mandates presuppose that resources provided to reduce class size will have a larger impact on student outcomes than resources that districts can spend as they see fit. I estimate the impact of Florida's statewide CSR policy by comparing the deviations from prior achievement trends in districts that were required to…

An Analysis of the Effects of Class Size on Student Achievement in Selected Middle Schools in the Sandhills Region of North Carolina

ERIC Educational Resources Information Center

Maples, Jeffrey B.

2009-01-01

The purpose of this study was to analyze the effects of class size and student achievement in mathematics and reading. The study focused on grades 6 through 8 and used the results of the North Carolina EOG tests in mathematics and reading for the academic year 2006-2007. This study examined the effects of class size and student achievement in…

Longitudinal Effects of Class Size Reductions on Attainment: Results from Hong Kong Primary Classrooms

ERIC Educational Resources Information Center

Galton, Maurice; Pell, Tony

2012-01-01

In a four-year study of the effect of class size on pupil outcomes in a sample of 36 primary schools in Hong Kong, it has been found that there are few positive differences in attainment between classes set at less than 25 pupils and those of normal size averaging 38. Three cohorts of pupils were studied. In Cohort 1 pupils spent 3 years in small…

Online stable isotope analysis of dissolved organic carbon size classes using size exclusion chromatography coupled to an isotope ratio mass spectrometer.

PubMed

Malik, Ashish; Scheibe, Andrea; LokaBharathi, P A; Gleixner, Gerd

2012-09-18

Stable isotopic content of dissolved organic carbon (δ(13)C-DOC) provides valuable information on its origin and fate. In an attempt to get additional insights into DOC cycling, we developed a method for δ(13)C measurement of DOC size classes by coupling high-performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) to online isotope ratio mass spectrometry (IRMS). This represents a significant methodological contribution to DOC research. The interface was evaluated using various organic compounds, thoroughly tested with soil-water from a C3-C4 vegetation change experiment, and also applied to riverine and marine DOC. δ(13)C analysis of standard compounds resulted in excellent analytical precision (≤0.3‰). Chromatography resolved soil DOC into 3 fractions: high molecular weight (HMW; 0.4-10 kDa), low molecular weight (LMW; 50-400 Da), and retained (R) fraction. Sample reproducibility for measurement of δ(13)C-DOC size classes was ±0.25‰ for HMW fraction, ± 0.54‰ for LMW fraction, and ±1.3‰ for R fraction. The greater variance in δ(13)C values of the latter fractions was due to their lower concentrations. The limit of quantification (SD ≤0.6‰) for each size fraction measured as a peak is 200 ng C (2 mg C/L). δ(13)C-DOC values obtained in SEC mode correlated significantly with those obtained without column in the μEA mode (p < 0.001, intercept 0.17‰), which rules out SEC-associated isotopic effects or DOC loss. In the vegetation change experiment, fractions revealed a clear trend in plant contribution to DOC; those in deeper soils and smaller size fractions had less plant material. It was also demonstrated that the technique can be successfully applied to marine and riverine DOC without further sample pretreatment.

Simulations and experiments on gas adsorption in novel microporous polymers

NASA Astrophysics Data System (ADS)

Larsen, Gregory Steven

Microporous materials represent a fascinating class of materials with a broad range of applications. The work presented here focuses on the use of a novel class of microporous material known as polymers of intrinsic micrioporosity, or PIMs, for use in gas separation and storage technologies. The aim of this research is to develop a detailed understanding of the relationship between the monomeric structure and the adsorptive performance of PIMs. First, a generalizable structure generation technique was developed such that simulation samples of PIM-1 recreated experimental densities, scattering, surface areas, pore size distributions, and adsorption isotherms. After validation, the simulations were applied as virtual experiments on several new PIMs with the intent to screen their capabilities as adsorbent materials and elucidate design principles for linear PIMs. The simulations are useful in understanding the unique properties such as pore size distribution and scattering observed experimentally.

Class Size Effects on Literacy Skills and Literacy Interest in First Grade: A Large-Scale Investigation

ERIC Educational Resources Information Center

Ecalle, Jean; Magnan, Annie; Gibert, Fabienne

2006-01-01

This article examines the impact of class size on literacy skills and on literacy interest in beginning readers from zones with specific educational needs in France. The data came from an experiment involving first graders in which teachers and pupils were randomly assigned to the different class types (small classes of 10-12 pupils vs. regular…

Connecting in Class? College Class Size and Inequality in Academic Social Capital

ERIC Educational Resources Information Center

Beattie, Irenee R.; Thiele, Megan

2016-01-01

College students who interact with professors and peers about academic matters have better college outcomes. Although institutional factors influence engagement, prior scholarship has not systematically examined whether class sizes affect students' academic interactions, nor whether race or first-generation status moderate such effects. We…

The Allocation of Teachers in Schools--An Alternative to the Class Size Dialogue.

ERIC Educational Resources Information Center

Loader, David N.

1978-01-01

This article looks beyond class size to such specifics as teachers' load, subject electives available, subject load, and different class groupings in developing a flow chart that gives added understanding and control over the variables relating to the deployment of teachers. (Author/IRT)

All We Need Is a Little Class.

ERIC Educational Resources Information Center

Krieger, Jean D.

This study was designed to discover the nature of interactions between effective teachers in regular-sized classes with 25 or more students and small-size classes with fewer than 18 students. Eleven public school primary classrooms were observed, and the interactions between the teacher and students were studied. Verbal and nonverbal interactions…

Predicting the Unpredictable: 75 Years of Experimental Evidence

NASA Astrophysics Data System (ADS)

Radin, Dean I.

2011-11-01

From time immemorial, people have reported foreknowledge of future events. To determine whether such experiences are best understood via conventional explanations, or whether a retrocausal phenomenon might be involved in some instances, researchers have conducted hundreds of controlled laboratory experiments over the past 75 years. These studies fall into four general classes, and each class has generated repeatable evidence consistent with retrocausation. The statistical results for a class of forced-choice studies is associated with odds against chance of about 1024; for a class of free-response studies, odds about 1020; for psychophysiological-based studies, odds about 1017; and for implicit decision studies, odds about 1010. Effect sizes observed in the latter three classes are nearly identical, indicating replication of similar underlying effects. These effects are also in close agreement with the average effect size across 25,000 conventional social psychology experiments conducted over the last century, suggesting that retrocausal phenomena may not be especially unique, at least not in terms of the magnitude of effect. Bayesian analyses of the most recent classes of experiments confirm that the evidence is strongly in favor of a genuine effect, with Bayes Factors ranging from 13,669 to 1 for implicit decision experiments, to 2.9×1013 to 1 for psychophysiological designs. For the two most recent classes of studies examining retrocausal effects via unconscious physiological or behavioral measures, 85 of 101 studies (84%) reported by 25 different laboratories from the United States, Italy, Spain, Holland, Austria, Sweden, England, Scotland, Iran, Japan, and Australia, have produced results in the direction predicted by a retrocausal effect (odds against chance = 1.3×1012, via a sign test). Assessment of the methodologies used in these studies has not identified plausible conventional alternatives for the observed outcomes, suggesting the existence of a genuine retrocausal phenomenon.

HPLC method development for evolving applications in the pharmaceutical industry and nanoscale chemistry

NASA Astrophysics Data System (ADS)

Castiglione, Steven Louis

As scientific research trends towards trace levels and smaller architectures, the analytical chemist is often faced with the challenge of quantitating said species in a variety of matricies. The challenge is heightened when the analytes prove to be potentially toxic or possess physical or chemical properties that make traditional analytical methods problematic. In such cases, the successful development of an acceptable quantitative method plays a critical role in the ability to further develop the species under study. This is particularly true for pharmaceutical impurities and nanoparticles (NP). The first portion of the research focuses on the development of a part-per-billion level HPLC method for a substituted phenazine-class pharmaceutical impurity. The development of this method was required due to the need for a rapid methodology to quantitatively determine levels of a potentially toxic phenazine moiety in order to ensure patient safety. As the synthetic pathway for the active ingredient was continuously refined to produce progressively lower amounts of the phenazine impurity, the approach for increasingly sensitive quantitative methods was required. The approaches evolved across four discrete methods, each employing a unique scheme for analyte detection. All developed methods were evaluated with regards to accuracy, precision and linear adherence as well as ancillary benefits and detriments -- e.g., one method in this evolution demonstrated the ability to resolve and detect other species from the phenazine class. The second portion of the research focuses on the development of an HPLC method for the quantitative determination of NP size distributions. The current methodology for the determination of NP sizes employs tunneling electron microscopy (TEM), which requires sample drying without particle size alteration and which, in many cases, may prove infeasible due to cost or availability. The feasibility of an HPLC method for NP size characterizations evolved across three methods, each employing a different approach for size resolution. These methods were evaluated primarily for sensitivity, which proved to be a substantial hurdle to further development, but does not appear to deter future research efforts.

Dynamic relationships between body size, species richness, abundance, and energy use in a shallow marine epibenthic faunal community

PubMed Central

Labra, Fabio A; Hernández-Miranda, Eduardo; Quiñones, Renato A

2015-01-01

We study the temporal variation in the empirical relationships among body size (S), species richness (R), and abundance (A) in a shallow marine epibenthic faunal community in Coliumo Bay, Chile. We also extend previous analyses by calculating individual energy use (E) and test whether its bivariate and trivariate relationships with S and R are in agreement with expectations derived from the energetic equivalence rule. Carnivorous and scavenger species representing over 95% of sample abundance and biomass were studied. For each individual, body size (g) was measured and E was estimated following published allometric relationships. Data for each sample were tabulated into exponential body size bins, comparing species-averaged values with individual-based estimates which allow species to potentially occupy multiple size classes. For individual-based data, both the number of individuals and species across body size classes are fit by a Weibull function rather than by a power law scaling. Species richness is also a power law of the number of individuals. Energy use shows a piecewise scaling relationship with body size, with energetic equivalence holding true only for size classes above the modal abundance class. Species-based data showed either weak linear or no significant patterns, likely due to the decrease in the number of data points across body size classes. Hence, for individual-based size spectra, the SRA relationship seems to be general despite seasonal forcing and strong disturbances in Coliumo Bay. The unimodal abundance distribution results in a piecewise energy scaling relationship, with small individuals showing a positive scaling and large individuals showing energetic equivalence. Hence, strict energetic equivalence should not be expected for unimodal abundance distributions. On the other hand, while species-based data do not show unimodal SRA relationships, energy use across body size classes did not show significant trends, supporting energetic equivalence. PMID:25691966

A standardized mean difference effect size for multiple baseline designs across individuals.

PubMed

Hedges, Larry V; Pustejovsky, James E; Shadish, William R

2013-12-01

Single-case designs are a class of research methods for evaluating treatment effects by measuring outcomes repeatedly over time while systematically introducing different condition (e.g., treatment and control) to the same individual. The designs are used across fields such as behavior analysis, clinical psychology, special education, and medicine. Emerging standards for single-case designs have focused attention on methods for summarizing and meta-analyzing findings and on the need for effect sizes indices that are comparable to those used in between-subjects designs. In the previous work, we discussed how to define and estimate an effect size that is directly comparable to the standardized mean difference often used in between-subjects research based on the data from a particular type of single-case design, the treatment reversal or (AB)(k) design. This paper extends the effect size measure to another type of single-case study, the multiple baseline design. We propose estimation methods for the effect size and its variance, study the estimators using simulation, and demonstrate the approach in two applications. Copyright © 2013 John Wiley & Sons, Ltd.

Class size as related to the use of technology, educational practices, and outcomes in Web-based nursing courses.

PubMed

Burruss, Nancy M; Billings, Diane M; Brownrigg, Vicki; Skiba, Diane J; Connors, Helen R

2009-01-01

With the expanding numbers of nursing students enrolled in Web-based courses and the shortage of faculty, class sizes are increasing. This exploratory descriptive study examined class size in relation to the use of technology and to particular educational practices and outcomes. The sample consisted of undergraduate (n = 265) and graduate (n = 863) students enrolled in fully Web-based nursing courses. The Evaluating Educational Uses of Web-based Courses in Nursing survey (Billings, D., Connors, H., Skiba, D. (2001). Benchmarking best practices in Web-based nursing courses. Advances in Nursing Science, 23, 41--52) and the Social Presence Scale (Gunawardena, C. N., Zittle, F. J. (1997). Social presence as a predictor of satisfaction within a computer-mediated conferencing environment. The American Journal of Distance Education, 11, 9-26.) were used to gather data about the study variables. Class sizes were defined as very small (1 to 10 students), small (11 to 20 students), medium (21 to 30 students), large (31 to 40 students), and very large (41 students and above). Descriptive and inferential statistics were used to analyze the data. There were significant differences by class size in students' perceptions of active participation in learning, student-faculty interaction, peer interaction, and connectedness. Some differences by class size between undergraduate and graduate students were also found, and these require further study.

Size-Energy Relationships in Ecological Communities

PubMed Central

Sewall, Brent J.; Freestone, Amy L.; Hawes, Joseph E.; Andriamanarina, Ernest

2013-01-01

Hypotheses that relate body size to energy use are of particular interest in community ecology and macroecology because of their potential to facilitate quantitative predictions about species interactions and to clarify complex ecological patterns. One prominent size-energy hypothesis, the energetic equivalence hypothesis, proposes that energy use from shared, limiting resources by populations or size classes of foragers will be independent of body size. Alternative hypotheses propose that energy use will increase with body size, decrease with body size, or peak at an intermediate body size. Despite extensive study, however, size-energy hypotheses remain controversial, due to a lack of directly-measured data on energy use, a tendency to confound distinct scaling relationships, and insufficient attention to the ecological contexts in which predicted relationships are likely to occur. Our goal, therefore, was to directly evaluate size-energy hypotheses while clarifying how results would differ with alternate methods and assumptions. We comprehensively tested size-energy hypotheses in a vertebrate frugivore guild in a tropical forest in Madagascar. Our test of size-energy hypotheses, which is the first to examine energy intake directly, was consistent with the energetic equivalence hypothesis. This finding corresponds with predictions of metabolic theory and models of energy distribution in ecological communities, which imply that body size does not confer an advantage in competition for energy among populations or size classes of foragers. This result was robust to different assumptions about energy regulation. Our results from direct energy measurement, however, contrasted with those obtained with conventional methods of indirect inference from size-density relationships, suggesting that size-density relationships do not provide an appropriate proxy for size-energy relationships as has commonly been assumed. Our research also provides insights into mechanisms underlying local size-energy relationships and has important implications for predicting species interactions and for understanding the structure and dynamics of ecological communities. PMID:23950873

Do Class Size Reductions Make a Difference to Classroom Practice? The Case of Hong Kong Primary Schools

ERIC Educational Resources Information Center

Galton, Maurice; Pell, Tony

2012-01-01

This paper describes changes which took place in 37 Hong Kong primary schools where class sizes were reduced from 38 to between 20 and 25. Chinese, English and mathematics classes were observed over three years from Primary 1 (aged 6) to Primary 3. For 75% of observations no child was the focus of the teacher's attention in large classes. Reducing…

Early Implementation of the Class Size Reduction Initiative.

ERIC Educational Resources Information Center

Illig, David C.

A survey of school districts was conducted to determine the initial progress and problems associated with the 1997 Class Size Reduction (CSR) Initiative. Data reveal that most school districts had enough space for smaller classes for at least two grade levels; small school districts were much less likely to report space constraints. The CSR did…

The Relationship of Class Size Effects and Teacher Salary

ERIC Educational Resources Information Center

Peevely, Gary; Hedges, Larry; Nye, Barbara A.

2005-01-01

The effects of class size on academic achievement have been studied for decades. Although the results of small-scale, randomized experiments and large-scale, econometric studies point to positive effects of small classes, some scholars see the evidence as ambiguous. Recent analyses from a 4-year, large-scale, randomized experiment on the effects…

Studying the Relative Strengths of Environmental Factors that Influence Echinoderm Body Size Trends

NASA Astrophysics Data System (ADS)

Low, A.; Randhawa, S.; Heim, N. A.; Payne, J.

2013-12-01

Body size is often a useful metric in observing how a clade responds to environmental changes. Previous research has uncovered how environmental factors such as carbon dioxide and oxygen levels influence body size evolution. However, we wanted to look into how these natural factors interact and which factors seem to have a stronger relative influence on echinoderm body size. We analyzed carbon dioxide levels, a proxy for paleotemperature, oxygen levels, and sea level. Our research process involved measuring and calculating the volume of Phanerozoic echinoderm fossils recorded in the Treatise on Invertebrate Paleontology, plotting their mean volumes over various natural factors, and using statistical tools such as correlation tests and the PaleoTS statistical analysis software to compare the relative strengths of these factors. Furthermore, we divided our data into the following three subsets to uncover more specific relationships: 1) A set that included all data of the phylum Echinodermata 2) A set that focused on the two classes with the most recorded data, Echinoidea and Crinoidea 3) A set that focused on the crinoid specimens that originated in the Paleozoic and in the post-Paleozoic. In the first subset, echinoderms had the strongest correlation with carbon dioxide, a proxy for temperature, and possessed a weaker correlation with oxygen. In the second subset, we discovered that the echinoid data also possessed a strong correlation with carbon dioxide and a weaker correlation with oxygen. For crinoids, we found that the class as a whole showed no strong correlation with any measured environmental factors. However, when we divided the crinoids based on age, we found that both Paleozoic and post-Paleozoic crinoids individually correlated strongly with sea level. However, some uncertainty with this correlation arose as the comparison of the environmental correlate models suggested that an unbiased random walk was the best fit for the data. This stands as a sharp contrast to the strong evidence provided by the appropriate graphs and correlation tests that indicate strong, dominant relationships between body size and environmental factors. Thus, though further research is necessary to settle such uncertainty, we were able to identify, observe, and compare the diversity in body size responses to environmental factors within echinoderms.

Power laws, discontinuities and regional city size distributions

USGS Publications Warehouse

Garmestani, A.S.; Allen, Craig R.; Gallagher, C.M.

2008-01-01

Urban systems are manifestations of human adaptation to the natural environment. City size distributions are the expression of hierarchical processes acting upon urban systems. In this paper, we test the entire city size distributions for the southeastern and southwestern United States (1990), as well as the size classes in these regions for power law behavior. We interpret the differences in the size of the regional city size distributions as the manifestation of variable growth dynamics dependent upon city size. Size classes in the city size distributions are snapshots of stable states within urban systems in flux.

The Effect of Phoneme Awareness Instruction on Students in Small Group and Whole Class Settings

ERIC Educational Resources Information Center

VanBoden, Angelique Fleurette

2011-01-01

Phoneme awareness instruction plays a crucial role in reading acquisition for young children. While this early literacy topic has been studied for over 30 years, and cited by the National Reading Panel Report (2000) as an important area for further research, no reports to date explore the influence of instructional group size on phoneme awareness…

Advances in the Application of Designed Ankyrin Repeat Proteins (DARPins) as Research Tools and Protein Therapeutics.

PubMed

Boersma, Ykelien L

2018-01-01

Nonimmunoglobulin scaffolds have been developed to overcome the limitations of monoclonal antibodies with regard to stability and size. Of these scaffolds, the class of designed ankyrin repeat proteins (DARPins) has advanced the most in biochemical and biomedical applications. This review focuses on the recent progress in DARPin technology, highlighting the scaffold's potential and possibilities.

Making "Right" Choices? An Ethnographic Account of Creativity, Performativity and Personalised Learning Policy, Concepts and Practices

ERIC Educational Resources Information Center

Beach, Dennis; Dovemark, Marianne

2009-01-01

This article uses ethnographic research from two Year 8 classes in two middle-sized secondary schools about a kilometre apart in a Swedish west-coast town to examine how new policies for personalised learning have developed in practice, in the performative cultures of modern schools in a commodity society. One school stands in a predominantly…

Information for forest process models: a review of NRS-FIA vegetation measurements

Treesearch

Charles D. Canham; William H. McWilliams

2012-01-01

The Forest and Analysis Program of the Northern Research Station (NRS-FIA) has re-designed Phase 3 measurements and intensified the sample intensity following a study to balance costs, utility, and sample size. The sampling scheme consists of estimating canopy-cover percent for six vegetation growth habits on 24-foot-radius subplots in four height classes and as an...

Assessing potential health risks to fish and humans using mercury concentrations in inland fish from across western Canada and the United States

USGS Publications Warehouse

Lepak, Jesse M.; Hooten, Mevin B.; Eagles-Smith, Collin A.; Tate, Michael T.; Lutz, Michelle A.; Ackerman, Joshua T.; Willacker, James J.; Jackson, Allyson K.; Evers, David C.; Wiener, James G.; Pritz, Colleen Flanagan; Davis, Jay

2016-01-01

Fish represent high quality protein and nutrient sources, but Hg contamination is ubiquitous in aquatic ecosystems and can pose health risks to fish and their consumers. Potential health risks posed to fish and humans by Hg contamination in fish were assessed in western Canada and the United States. A large compilation of inland fish Hg concentrations was evaluated in terms of potential health risk to the fish themselves, health risk to predatory fish that consume Hg contaminated fish, and to humans that consume Hg contaminated fish. The probability that a fish collected from a given location would exceed a Hg concentration benchmark relevant to a health risk was calculated. These exceedance probabilities and their associated uncertainties were characterized for fish of multiple size classes at multiple health-relevant benchmarks. The approach was novel and allowed for the assessment of the potential for deleterious health effects in fish and humans associated with Hg contamination in fish across this broad study area. Exceedance probabilities were relatively common at low Hg concentration benchmarks, particularly for fish in larger size classes. Specifically, median exceedances for the largest size classes of fish evaluated at the lowest Hg concentration benchmarks were 0.73 (potential health risks to fish themselves), 0.90 (potential health risk to predatory fish that consume Hg contaminated fish), and 0.97 (potential for restricted fish consumption by humans), but diminished to essentially zero at the highest benchmarks and smallest fish size classes. Exceedances of benchmarks are likely to have deleterious health effects on fish and limit recommended amounts of fish humans consume in western Canada and the United States. Results presented here are not intended to subvert or replace local fish Hg data or consumption advice, but provide a basis for identifying areas of potential health risk and developing more focused future research and monitoring efforts.

Factors associated with long-term species composition in dry tropical forests of Central India

NASA Astrophysics Data System (ADS)

Agarwala, M.; DeFries, R. S.; Qureshi, Q.; Jhala, Y. V.

2016-10-01

The long-term future of species composition in forests depends on regeneration. Many factors can affect regeneration, including human use, environmental conditions, and species’ traits. This study examines the influence of these factors in a tropical deciduous forest of Central India, which is heavily used by local, forest-dependent residents for livestock grazing, fuel-wood extraction, construction and other livelihood needs. We measure size-class proportions (the ratio of abundance of a species at a site in a higher size class to total abundance in both lower and higher size classes) for 39 tree species across 20 transects at different intensities of human use. The size-class proportions for medium to large trees and for small to medium-sized trees were negatively associated with species that are used for local construction, while size class proportions for saplings to small trees were positively associated with those species that are fire resistant and negatively associated with livestock density. Results indicate that grazing and fire prevent non-fire resistant species from reaching reproductive age, which can alter the long term composition and future availability of species that are important for local use and ecosystem services. Management efforts to reduce fire and forest grazing could reverse these impacts on long-term forest composition.

A Descriptive Evaluation of the Federal Class-Size Reduction Program: Final Report

ERIC Educational Resources Information Center

Millsap, Mary Ann; Giancola, Jennifer; Smith, W. Carter; Hunt, Dana; Humphrey, Daniel C.; Wechsler, Marjorie E.; Riehl, Lori M.

2004-01-01

The federal Class-Size Reduction (CSR) Program, P.L. 105-277, begun in Fiscal Year 1999, represented a major federal commitment to help school districts hire additional qualified teachers, especially in the early elementary grades, so children would learn in smaller classes. The CSR program also allowed funds to be spent as professional…

Class-Size Effects on Adolescents' Mental Health and Well-Being in Swedish Schools

ERIC Educational Resources Information Center

Jakobsson, Niklas; Persson, Mattias; Svensson, Mikael

2013-01-01

This paper analyzes whether class size has an effect on the prevalence of mental health problems and well-being among adolescents in Swedish schools. We use cross-sectional data collected in year 2008 covering 2755 Swedish adolescents in ninth grade from 40 schools and 159 classes. We utilize different econometric approaches to address potential…

Utilizing Online Education in Florida to Meet Mandated Class Size Limitations

ERIC Educational Resources Information Center

Mattox, Kari Ann

2012-01-01

With the passage of a state constitutional amendment in 2002, Florida school districts faced the challenge of meeting class size mandates in core subjects, such as mathematics, English, and science by the 2010-2011 school year, or face financial penalties. Underpinning the amendment's goals was the argument that smaller classes are more effective…

Class Size Reduction: Lessons Learned from Experience. Policy Brief No. Twenty-Three.

ERIC Educational Resources Information Center

McRobbie, Joan; Finn, Jeremy D.; Harman, Patrick

New federal proposals have fueled national interest in class-size reduction (CSR). However, CSR raises numerous concerns, some of which are addressed in this policy brief. The text draws on the experiences of states and districts that have implemented CSR. The brief addresses the following 15 concerns: Do small classes in and of themselves affect…

Predicting size limit of wild blood python (python brongersmai stull, 1938) harvesting in north sumatera

NASA Astrophysics Data System (ADS)

Mangantar Pardamean Sianturi, Markus; Jumilawaty, Erni; Delvian; Hartanto, Adrian

2018-03-01

Blood python (Python brongersmai Stull, 1938) is one of heavily exploited wildlife in Indonesia. The high demands on its skin trade have made its harvesting regulated under quota-based setting by the government to prevent over-harvesting. To gain understanding on the sustainability of P. brongersmai in the wild, biological characters of wild-caught specimens were studied. Samples were collected from two slaughterhouses from Rantau Prapat and Langkat. Parameters measured were morphological (Snout-vent length (SVL), body mass, abdomen width) and anatomical characters (Fat classes). Total samples of P. brongersmai in this research were 541 with 269 male and 272 female snakes. Female snakes had the highest proportion of individuals with the best quality of abdominal fat reserves (Class 3). Linear models are built and tested for its significance in relation between fat classes as anatomical characters and morphological characters. All tested morphological characters were significant in female snakes. By using linear equation models, we generate size limit to prioritize harvesting in the future. We suggest the use of SVL and stomach width ranging between 139,7 – 141,5 cm and 24,72 – 25,71 cm respectively to achieve sustainability of P. brongersmai in the wild.

Health Science students' evaluation of courses and Instructors: the effect of response rate and class size interaction.

PubMed

Kuwaiti, Ahmed Al

2015-01-01

This study aims at investigating the effect of response rate and class size interaction on students' evaluation of instructors and the courses offered at heath science colleges in Saudi Arabia. A retrospective study design was adapted to ascertain Course Evaluation Surveys (CES) conducted at the health science colleges of the University of Dammam [UOD] in the academic year 2013-2014. Accordingly, the CES data which was downloaded from an exclusive online application 'UDQUEST' which includes 337 different courses and 15,264 surveys were utilized in this study. Two-way analysis of variance was utilized to test whether there is any significant interaction between the class size and the response rate on the students' evaluation of courses and instructors. The study showed that high response rate is required for student evaluation of instructors at Health Science colleges when the class size is small whereas a medium response rate is required for students' evaluation of courses. On the other hand, when the class size is medium, a medium or high response rate is needed for students' evaluation of both instructors and courses. The results of this study recommend that the administrators of the health science colleges to be aware of the interpretation of students' evaluations of courses and instructors. The study also suggests that the interaction between response rate and class size is a very important factor that needs to be taken into consideration while interpreting the findings of the students' evaluation of instructors and courses.

"Mini-array" transcriptional analysis of the Listeria monocytogenes lecithinase operon as a class project: A student investigative molecular biology laboratory experience*.

PubMed

Christensen, Douglas; Jovic, Marko

2006-05-01

This report describes a molecular biotechnology-based laboratory curriculum developed to accompany an undergraduate genetics course. During the course of a semester, students researched the pathogen, developed a research question, designed experiments, and performed transcriptional analysis of a set of genes that confer virulence to the food-borne pathogen, Listeria monocytogenes. Gene fragments were amplified via PCR and utilized in "mini-arrays," a dot-blot-based format suitable for the simultaneous transcriptional analysis of multiple genes. The project provides exposure to a wide range of molecular techniques and can be easily modified for variations in class size. Data are generated at various steps of the process, allowing for student interpretation, troubleshooting, and assessment opportunities. Copyright © 2006 International Union of Biochemistry and Molecular Biology, Inc.

Mapped Plot Patch Size Estimates

Treesearch

Paul C. Van Deusen

2005-01-01

This paper demonstrates that the mapped plot design is relatively easy to analyze and describes existing formulas for mean and variance estimators. New methods are developed for using mapped plots to estimate average patch size of condition classes. The patch size estimators require assumptions about the shape of the condition class, limiting their utility. They may...

The predictors of chemistry achievement of 12th grade students in secondary schools in the United Arab Emirates

NASA Astrophysics Data System (ADS)

Khalaf, Ali Khalfan

2000-10-01

The purpose of this study is to explore variables related to chemistry achievement of 12th grade science students in the United Arab Emirates (UAE). The focus is to identify student, teacher, and school variables that predict chemistry achievement. The analysis sample included 204 males and 252 females in 66 classes in 60 schools from 10 districts or bureaus of education in the UAE. Thirty-two male and 33 female chemistry teachers and 60 school principals were included. The Khalaf Chemistry Achievement Test, GALT, the Student Questionnaire, Teacher Questionnaire, and School Information Questionnaire were administered. Descriptive statistics, correlations, analyses of variance, factor analysis, and stepwise multiple linear regression analyses were done. The results indicate that demographic, home environment, prior knowledge, scholastic ability, attitudes and perceptions related to chemistry and science, and student perception of instructional practices variables correlated with student chemistry achievement. The amount of help teachers received from the supervisor, class size, and courses in geology were teacher variables that correlated with class chemistry achievement. Nine school variables involving school, division, and class sizes correlated with school chemistry achievement. Analyses of variance revealed significant interaction effects: district by school size and district by student gender. In two districts, students in small schools achieved better than those in large schools. Generally female students achieved equal to or better than males. Three factors from the factor analysis: School Size, Prior Student Achievement, and Student Perception of Teacher Effectiveness, correlated with school chemistry achievement. The results of the multiple linear regression indicated that the factors of Prior Student Achievement, Student Perception of Teacher Effectiveness, and Teacher Experience and Expertise accounted for 45% of the variance in school chemistry achievement. Results indicate that the strongest predictors of chemistry achievement are prior achievement in science, Arabic language, and mathematics; student perception of teacher effectiveness; and teacher experience and expertise. Females tend to achieve better in chemistry than males. No nationality differences were found and the relationship of school size to chemistry achievement was inconclusive. Recommendations related to chemistry and science are presented. These include curriculum, school practice, teacher professional development, and future research.

A Comparison of Online, Video Synchronous, and Traditional Learning Modes for an Introductory Undergraduate Physics Course

NASA Astrophysics Data System (ADS)

Faulconer, E. K.; Griffith, J.; Wood, B.; Acharyya, S.; Roberts, D.

2018-05-01

While the equivalence between online and traditional classrooms has been well-researched, very little of this includes college-level introductory Physics. Only one study explored Physics at the whole-class level rather than specific course components such as a single lab or a homework platform. In this work, we compared the failure rate, grade distribution, and withdrawal rates in an introductory undergraduate Physics course across several learning modes including traditional face-to-face instruction, synchronous video instruction, and online classes. Statistically significant differences were found for student failure rates, grade distribution, and withdrawal rates but yielded small effect sizes. Post-hoc pair-wise test was run to determine differences between learning modes. Online students had a significantly lower failure rate than students who took the class via synchronous video classroom. While statistically significant differences were found for grade distributions, the pair-wise comparison yielded no statistically significance differences between learning modes when using the more conservative Bonferroni correction in post-hoc testing. Finally, in this study, student withdrawal rates were lowest for students who took the class in person (in-person classroom and synchronous video classroom) than online. Students that persist in an online introductory Physics class are more likely to achieve an A than in other modes. However, the withdrawal rate is higher from online Physics courses. Further research is warranted to better understand the reasons for higher withdrawal rates in online courses. Finding the root cause to help eliminate differences in student performance across learning modes should remain a high priority for education researchers and the education community as a whole.

Theoretical Studies of the Kinetics of First-Order Phase Transitions.

NASA Astrophysics Data System (ADS)

Zheng, Qiang

This thesis involves theoretical studies of the kinetics of orderings in three classes of systems. The first class involves problems of phase separation in which the order parameter is conserved, such as occurs in the binary alloy Al-Zn. A theory is developed for the late stages of phase separation in the droplet regime for two -dimensional systems, namely, Ostwald ripening in two dimensions. The theory considers droplet correlations, which was neglected before, by a proper treatment of the screening effect of the correlations. This correlation effect is found that it does not alert the scaling features of phase separation, but significantly changes the shape of droplet-size distribution function. Further experiments and computer simulations are needed before this long-time subject may be closed. A second class of problem involves a study of the finite-size effects on domain growth described by the Allen-Cahn dynamics. Based on a theoretical approach of Ohta, Jasnow, and Kawasaki the explicit scaling functions for the scattering intensity for hypercubes and films are obtained. These results are for the cases in which the order-parameter is not conserved, such as in an order-disorder transition in alloys. These studies will be relevant to the experimental and computer simulation research projects currently being carried out in the United States and Europe. The last class of problems involves orderings in strong correlated systems, namely, the growth of Breath Figures. A special feature of this class of problems is that the coalescence effect. A theoretical model is proposed which can handle the two growth mechanisms, the individual droplet growth and coalescence simultaneously. Under certain approximations, the droplet-size distribution function is obtained analytically, and is in qualitative agreement with computer simulations. Our model also suggests that there may be an interesting relationship between the growth of Breath Figures and a geometric structure (ultrametricity) of general complex systems.

The Effectiveness of School-Type Classes Compared to the Traditional Lecture/Tutorial Method for Teaching Quantitative Methods to Business Students.

ERIC Educational Resources Information Center

Goldfinch, Judy

1996-01-01

A study compared the effectiveness of two methods (medium-size class instruction and large lectures with tutorial sessions) for teaching mathematics and statistics to first-year business students. Students and teachers overwhelmingly preferred the medium-size class method, which produced higher exam scores but had no significant effect on…

The Smallest Lunar Grains: Analytical TEM Characterization of the Sub-micron Size Fraction of a Mare Soil

NASA Technical Reports Server (NTRS)

Thompson, M.; Christoffersen, R.

2010-01-01

The chemical composition, mineralogical type, and morphology of lunar regolith grains changes considerably with decreasing size, and below the approx.25 m size range the correlation between these parameters and remotely-sensed lunar surface properties connected to space weathering increases significantly. Although trends for these parameters across grain size intervals greater than 20 m are now well established, the 0 to 20 m size interval remains relatively un-subdivided with respect to variations in grain modal composition, chemistry and microstructure. Of particular interest in this size range are grains in the approximate < 1 m diameter class, whose fundamental properties are now the focus of lunar research pertaining to electrostatic grain transport, dusty plasmas, and lunar dust effects on crew health and exploration systems. In this study we have used analytical transmission electron microscopy (TEM) to characterize the mineralogy, microstructure and major element composition of grains below the 1 m size threshold in lunar soil 10084.

The Future of Small- and Medium-Sized Communities in the Prairie Region.

ERIC Educational Resources Information Center

Wellar, Barry S., Ed.

Four papers are featured. The first is a statistical overview and analysis of past, present and future happenings to small communities in the Region; it focuses on two indicators: (1) population growth or declining community class size and, (2) the changing distribution of commercial outlets by community class size. The other three papers report…

Channel catfish Ictalurus punctatus size and feed conversion ratio

USDA-ARS?s Scientific Manuscript database

Channel catfish, Ictalurus punctatus, of five size-classes were stocked into 20, 0.04-ha earthen ponds at a rate of 14,826 fish/ha. Mean initial weights for each size-class were 0.232, 0.458, 0.678, 0.911, and 1.10 kg/fish. Four ponds were randomly allotted to each treatment. A commercial 28% protei...

Operationally Comparable Effect Sizes for Quantifying Changes in Behavior, with Application to Meta-Analysis of Single-Case Studies

ERIC Educational Resources Information Center

Pustejovsky, James E.

2013-01-01

Single-case designs (SCDs) are a class of research methods for evaluating intervention effects by taking repeated measurements of an outcome over time on a single case, both before and after the deliberate introduction of a treatment. SCDs are used heavily in fields such as special education, school psychology, social work, and applied behavior…

The Effects of Faculty Status, Faculty Gender, Field of Study, and Class Size on the Use of Blogs, Wikis, and Discussion Boards

ERIC Educational Resources Information Center

Yang, Dazhi; Spear, Caile E.

2017-01-01

This study examined faculty's use of time intensive Web 2.0 technologies (blogs, discussion forums, and wikis) in teaching during a university's quest for higher research productivity and higher ranking in the Carnegie Classification. Results show there was a difference in using Web 2.0 technologies in teaching between faculty with different…

An Investigation of Burn-Out Levels of Teachers Working in Elementary and Secondary Educational Institutions and Their Attitudes to Classroom Management

ERIC Educational Resources Information Center

Yavuz, Mustafa

2009-01-01

In the present study, the burn-out levels of teachers working in elementary and secondary educational institutions and their attitudes and beliefs regarding classroom management are investigated with respect to gender, job seniority, class size and the types of schools they have been working in. This is a survey method research and quantitative…

Fuel deposition rates of montane and subalpine conifers in the central Sierra Nevada, California, USA

USGS Publications Warehouse

van Wagtendonk, J.W.; Moore, P.E.

2010-01-01

Fire managers and researchers need information on fuel deposition rates to estimate future changes in fuel bed characteristics, determine when forests transition to another fire behavior fuel model, estimate future changes in fuel bed characteristics, and parameterize and validate ecosystem process models. This information is lacking for many ecosystems including the Sierra Nevada in California, USA. We investigated fuel deposition rates and stand characteristics of seven montane and four subalpine conifers in the Sierra Nevada. We collected foliage, miscellaneous bark and crown fragments, cones, and woody fuel classes from four replicate plots each in four stem diameter size classes for each species, for a total of 176 sampling sites. We used these data to develop predictive equations for each fuel class and diameter size class of each species based on stem and crown characteristics. There were consistent species and diameter class differences in the annual amount of foliage and fragments deposited. Foliage deposition rates ranged from just over 50 g m-2 year-1 in small diameter mountain hemlock stands to ???300 g m-2 year-1 for the three largest diameter classes of giant sequoia. The deposition rate for most woody fuel classes increased from the smallest diameter class stands to the largest diameter class stands. Woody fuel deposition rates varied among species as well. The rates for the smallest woody fuels ranged from 0.8 g m-2 year-1 for small diameter stands of Jeffrey pine to 126.9 g m-2 year-1 for very large diameter stands of mountain hemlock. Crown height and live crown ratio were the best predictors of fuel deposition rates for most fuel classes and species. Both characteristics reflect the amount of crown biomass including foliage and woody fuels. Relationships established in this study allow predictions of fuel loads to be made on a stand basis for each of these species under current and possible future conditions. These predictions can be used to estimate fuel treatment longevity, assist in determining fuel model transitions, and predict future changes in fuel bed characteristics.

Birth order, family size, and intelligence.

PubMed

Belmont, L; Marolla, F A

1973-12-14

The relation of birth order and family size to intellectual performance, as measured by the Raven Progressive Matrices, was examined among nearly all of 400,000 19-year-old males born in the Netherlands in 1944 through 1947. It was found that birth order and family size had independent effects on intellectual performance. Effects of family size were not present in all social classes, but effects of birth order were consistent across social class.

Size-Class Effect Contributes to Tree Species Assembly through Influencing Dispersal in Tropical Forests

PubMed Central

Hu, Yue-Hua; Kitching, Roger L.; Lan, Guo-Yu; Zhang, Jiao-Lin; Sha, Li-Qing; Cao, Min

2014-01-01

We have investigated the processes of community assembly using size classes of trees. Specifically our work examined (1) whether point process models incorporating an effect of size-class produce more realistic summary outcomes than do models without this effect; (2) which of three selected models incorporating, respectively environmental effects, dispersal and the joint-effect of both of these, is most useful in explaining species-area relationships (SARs) and point dispersion patterns. For this evaluation we used tree species data from the 50-ha forest dynamics plot in Barro Colorado Island, Panama and the comparable 20 ha plot at Bubeng, Southwest China. Our results demonstrated that incorporating an size-class effect dramatically improved the SAR estimation at both the plots when the dispersal only model was used. The joint effect model produced similar improvement but only for the 50-ha plot in Panama. The point patterns results were not improved by incorporation of size-class effects using any of the three models. Our results indicate that dispersal is likely to be a key process determining both SARs and point patterns. The environment-only model and joint-effects model were effective at the species level and the community level, respectively. We conclude that it is critical to use multiple summary characteristics when modelling spatial patterns at the species and community levels if a comprehensive understanding of the ecological processes that shape species’ distributions is sought; without this results may have inherent biases. By influencing dispersal, the effect of size-class contributes to species assembly and enhances our understanding of species coexistence. PMID:25251538

Voices from the Field: The Perceptions of Teachers and Principals on the Class Size Reduction Program in a Large Urban School District.

ERIC Educational Resources Information Center

Munoz, Marco A.; Portes, Pedro R.

A class size reduction (CSR) program was implemented in a large low-performing urban elementary school district. The CSR program helps schools improve student learning by hiring additional teachers so that children in the early elementary grades can attend smaller classes. This study used a participant-oriented evaluation model to examine the…

Most microbeads in a preliminary survey of personal care products are smaller than the typical 330µm trawl mesh size used in surface water surveys

NASA Astrophysics Data System (ADS)

Conkle, J. L.; Baez-Del Valle, C.; Turner, J.

2016-02-01

Research on plastic debris in aquatic environments, particularly the ocean, has recently exploded due to our emerging understanding of their ubiquitous presence and organismal effects. One study estimated that hundreds of thousands of tons of plastic float at our ocean surface, while another estimated that up to 12.7 million metric tons enter the ocean in a year. These studies produced reasonable estimates of oceanic loads, but research is needed to understand the sources and properties of plastics, particularly microplastics, entering the environment. In this preliminary study, polyethylene (PE) microbeads from 6 facial scrubs, 4 body washes and 3 toothpaste products were extracted and quantified by mass and particle count for the following size classes: 50, 100, 200, 300, 400, 500 and 1000µm. Within the product classes, roughly half (face scrub, 55% and body wash, 48%) to nearly all (toothpaste, 97%) of PE microbeads on a mass basis were smaller than 300µm in diameter. When examining the size distribution by particle count, the results were even more astounding. Nearly all PE microbeads were smaller than 300µm for face scrub (95%), body wash (97%) and toothpaste (100%). The 300µm particle diameter is significant, as major surveys in the published literature (Eriksen et al., 2014; Law et al, 2014) used 330µm or greater mesh size to sample plastic debris and estimate oceanic plastic loads. Therefore, these published surveys, which are some of our best estimates of plastic debris at the ocean surface, likely underestimate total environmental loads because they may exclude half of the mass and nearly all of the individual PE microbead particles that enter our waste stream and potentially surface waters after the use of personal care products.

Developing an Undergraduate Astronomical Research Program

NASA Astrophysics Data System (ADS)

Genet, R. M.

2007-05-01

Time-series astronomical photometry is an area of scientific research well suited to amateurs and undergraduates, and their backyard and campus observatories. I describe two past one-semester community college research programs, one six year ago and one last fall (2006), as well as a program planned for this coming fall (2007). The 2001 program, a course at Central Arizona College, utilized a robotic telescope at the Fairborn Observatory. Results were presented at the 200th meeting of the American Astronomical Society. This past fall, three students, in a 17-week, one-semester course at Cuesta College, were able to plan a research program, make several thousand CCD photometric observations, reduce and analyze their data, write up their results and, on the last day of class, send their paper off to a refereed journal, the JAAVSO. A course is being offered this coming fall (2007) that will involve about a dozen students (including high school students), several local amateur astronomers, and at least three CCD- equipped semi-automatic telescopes. Potential solutions to "scaling up" challenges created by increased class size are discussed.

40 CFR 144.28 - Requirements for Class I, II, and III wells authorized by rule.

Code of Federal Regulations, 2010 CFR

2010-07-01

... proposed test or measurement to be made; (D) The amount, size, and location (by depth) of casing to be left..., internal pressure, and axial loading; (iv) Hole size; (v) Size and grade of all casing strings; and (vi... Class III wells the owner or operator shall provide to the Director a qualitative analysis and ranges in...

Determining stocking, forest type and stand-size class from forest inventory data

Treesearch

Mark H. Hansen; Jerold T. Hahn

1992-01-01

This paper describes the procedures used by North Central Forest Experiment Station's Forest Inventory and Analysis Work Unit (NCFIA) in determining stocking, forest type, and stand-size class. The stocking procedure assigns a portion of the stocking to individual trees measured on NCFIA 10-point field plots. Stand size and forest type are determined as functions...

Shape Comparison Between 0.4–2.0 and 20–60 lm Cement Particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holzer, L.; Flatt, R; Erdogan, S

Portland cement powder, ground from much larger clinker particles, has a particle size distribution from about 0.1 to 100 {micro}m. An important question is then: does particle shape depend on particle size? For the same cement, X-ray computed tomography has been used to examine the 3-D shape of particles in the 20-60 {micro}m sieve range, and focused ion beam nanotomography has been used to examine the 3-D shape of cement particles found in the 0.4-2.0 {micro}m sieve range. By comparing various kinds of computed particle shape data for each size class, the conclusion is made that, within experimental uncertainty, bothmore » size classes are prolate, but the smaller size class particles, 0.4-2.0 {micro}m, tend to be somewhat more prolate than the 20-60 {micro}m size class. The practical effect of this shape difference on the set-point was assessed using the Virtual Cement and Concrete Testing Laboratory to simulate the hydration of five cement powders. Results indicate that nonspherical aspect ratio is more important in determining the set-point than are the actual shape details.« less

Parenting Stress among Low-Income and Working-Class Fathers: The Role of Employment

PubMed Central

Nomaguchi, Kei; Johnson, Wendi

2014-01-01

Contemporary norms of fatherhood emphasize the dual demands of breadwinning and daily involvement in childcare. Recent qualitative research suggests that working-class fathers find it difficult to meet these demands due to job instability and workplace inflexibility. Yet, little quantitative research has examined how employment characteristics are related to fathers’ parenting stress, in comparison with mothers’. Analyses using data from the Fragile Families and Child Wellbeing Study (N = 3,165) show that unemployment and workplace inflexibility, but not overwork, multiple jobs, odd-jobs, and nonstandard hours, are related to more parenting stress for fathers. Although these two factors are also related to more parenting stress for mothers, nuanced gender differences emerged: these are better predictors than other parental or child characteristics for fathers only, and the effect size of workplace inflexibility is greater for fathers than mothers. In sum, securing a job with flexible schedule is central to reducing fathers’ parenting stress. PMID:27616804

Parenting Stress among Low-Income and Working-Class Fathers: The Role of Employment.

PubMed

Nomaguchi, Kei; Johnson, Wendi

2016-08-01

Contemporary norms of fatherhood emphasize the dual demands of breadwinning and daily involvement in childcare. Recent qualitative research suggests that working-class fathers find it difficult to meet these demands due to job instability and workplace inflexibility. Yet, little quantitative research has examined how employment characteristics are related to fathers' parenting stress, in comparison with mothers'. Analyses using data from the Fragile Families and Child Wellbeing Study ( N = 3,165) show that unemployment and workplace inflexibility, but not overwork, multiple jobs, odd-jobs, and nonstandard hours, are related to more parenting stress for fathers. Although these two factors are also related to more parenting stress for mothers, nuanced gender differences emerged: these are better predictors than other parental or child characteristics for fathers only, and the effect size of workplace inflexibility is greater for fathers than mothers. In sum, securing a job with flexible schedule is central to reducing fathers' parenting stress.

Body Image Disturbance in 1000 Male Appearance and Performance Enhancing Drug Users

PubMed Central

Hildebrandt, Tom; Alfano, Lauren; Langenbucher, James W.

2010-01-01

Body image disturbance (BID) among men has only recently become a phenomenon of clinical significance with noted heterogeneity in the behavioral consequences of these disturbances. The degree of heterogeneity among appearance and performance enhancing drug (APED) users is unknown and an empirically derived framework for studying BID is necessary. 1000 APED users were recruited via the Internet and they completed a comprehensive online assessment APED use patterns, motivations, consequences, and BID. Data were evaluated using latent trait, latent class, and factor mixture models. Model results were validated using a range of covariates including cycle characteristics, age, APED history, and APED risk. A 1-Factor, 4-Class model provided the best fit to the data with Class 1 scoring the highest on all measures of BID and Class 4 the lowest on all measures. Class 2 differed in their preference for being lean over muscular and Class 3 preferred adding mass and size. Each class was associated with unique risks, APED history, and training identity. Not all APED users suffer from significant BID and there are unique profiles for those with elevated BID. Future research on male BID should account for this structure in order to better define relevant diagnostic categories and evaluate the clinical significance of BID. PMID:20110092

CONTINUITY AND CHANGE IN THE AMERICAN CLASS STRUCTURE: WORKPLACE OWNERSHIP AND AUTHORITY RELATIONS FROM 1972 TO 2010

PubMed Central

Wodtke, Geoffrey T.

2016-01-01

This study investigates changes in the American class structure—defined in terms of workplace ownership and authority relations—and trends in status group disparities in class attainment from 1972 to 2010. Although theory and prior research suggest a variety of appreciable changes in class structure and class attainment, data from the General Social Survey indicate that the sizes of different classes remained fairly stable during this time period and that status group disparities in access to ownership and authority persisted largely intact. The 1970s witnessed a decline in the proportion of workers and growth in the proportion of managers and proprietors, but these trends reversed in the 1980s. As a result, by the late 2000s, the ownership and authority structure of the U.S. economy closely resembled that of the early 1970s. Racial and gender disparities in class attainment also did not change significantly over time: blacks and women remained underrepresented (relative to whites and men) in positions of ownership and authority throughout this period. Even after controlling for an extensive set of human capital characteristics, family constraints, and structural economic factors, there is little evidence of status group integration across these key dimensions of economic power. PMID:27134335

CONTINUITY AND CHANGE IN THE AMERICAN CLASS STRUCTURE: WORKPLACE OWNERSHIP AND AUTHORITY RELATIONS FROM 1972 TO 2010.

PubMed

Wodtke, Geoffrey T

2015-12-01

This study investigates changes in the American class structure-defined in terms of workplace ownership and authority relations-and trends in status group disparities in class attainment from 1972 to 2010. Although theory and prior research suggest a variety of appreciable changes in class structure and class attainment, data from the General Social Survey indicate that the sizes of different classes remained fairly stable during this time period and that status group disparities in access to ownership and authority persisted largely intact. The 1970s witnessed a decline in the proportion of workers and growth in the proportion of managers and proprietors, but these trends reversed in the 1980s. As a result, by the late 2000s, the ownership and authority structure of the U.S. economy closely resembled that of the early 1970s. Racial and gender disparities in class attainment also did not change significantly over time: blacks and women remained underrepresented (relative to whites and men) in positions of ownership and authority throughout this period. Even after controlling for an extensive set of human capital characteristics, family constraints, and structural economic factors, there is little evidence of status group integration across these key dimensions of economic power.

Class IA phosphoinositide 3-kinase regulates heart size and physiological cardiac hypertrophy.

PubMed

Luo, Ji; McMullen, Julie R; Sobkiw, Cassandra L; Zhang, Li; Dorfman, Adam L; Sherwood, Megan C; Logsdon, M Nicole; Horner, James W; DePinho, Ronald A; Izumo, Seigo; Cantley, Lewis C

2005-11-01

Class I(A) phosphoinositide 3-kinases (PI3Ks) are activated by growth factor receptors, and they regulate, among other processes, cell growth and organ size. Studies using transgenic mice overexpressing constitutively active and dominant negative forms of the p110alpha catalytic subunit of class I(A) PI3K have implicated the role of this enzyme in regulating heart size and physiological cardiac hypertrophy. To further understand the role of class I(A) PI3K in controlling heart growth and to circumvent potential complications from the overexpression of dominant negative and constitutively active proteins, we generated mice with muscle-specific deletion of the p85alpha regulatory subunit and germ line deletion of the p85beta regulatory subunit of class I(A) PI3K. Here we show that mice with cardiac deletion of both p85 subunits exhibit attenuated Akt signaling in the heart, reduced heart size, and altered cardiac gene expression. Furthermore, exercise-induced cardiac hypertrophy is also attenuated in the p85 knockout hearts. Despite such defects in postnatal developmental growth and physiological hypertrophy, the p85 knockout hearts exhibit normal contractility and myocardial histology. Our results therefore provide strong genetic evidence that class I(A) PI3Ks are critical regulators for the developmental growth and physiological hypertrophy of the heart.

Examining the effect of publishing of bill sizes to reduce information asymmetry on healthcare costs.

PubMed

Wong, C Y; Wu, E; Wong, T Y

2007-01-01

Information asymmetry has been offered as a reason for unnecessarily high costs in certain industries where significant information asymmetry traditionally exists between providers and consumers, such as healthcare. The purpose of this paper is to examine the impact of the introduction of publishing of bill size as a means to reduce healthcare costs. Specifically, we aim to examine if this initiative to decrease information asymmetry on healthcare prices between healthcare providers and patients, and between healthcare providers themselves, will lead to lower prices for patients. Bill size data of 29 commonly occurring diagnosis-related groups (DRGs) for two ward classes (B2 and C) over a 16- month period were studied. Each ward class was studied separately, i.e. involving 58 DRG data sets. The mean bill size data as well as that of 50th and 90th percentile bill sizes were examined. The study involved some 46,000 inpatient episodes which occurred in the five public sector acute general hospitals of Singapore. Mean prices dropped by 4.14 percent and 9.64 percent for B2 and C classes, respectively. 50 out of 58 DRG data sets showed a drop in prices. Bill sizes at the 50th percentile dropped by 7.95 percent and 10.12 percent for B2 and C classes, respectively; while at the 90th percentile, the corresponding figures were decreases of 8.01 percent and 11.4 percent for the two ward classes. The act of publishing bill sizes has led to less information asymmetry among providers, thereby facilitating more competitive behaviour among hospitals and lower bill sizes.

Probability Assessment of Mega-thrust Earthquakes in Global Subduction Zones　-from the View of Slip Deficit-

NASA Astrophysics Data System (ADS)

Ikuta, R.; Mitsui, Y.; Ando, M.

2014-12-01

We studied inter-plate slip history for about 100 years using earthquake catalogs. On assumption that each earthquake has stick-slip patch centered in its centroid, we regard cumulative seismic slips around the centroid as representing the inter-plate dislocation. We evaluated the slips on the stick-slip patches of over-M5-class earthquakes prior to three recent mega-thrust earthquakes, the 2004 Sumatra (Mw9.2), the 2010 Chile (Mw8.8), and the 2011 Tohoku (Mw9.0) around them. Comparing the cumulative seismic slips with the plate convergence, the slips before the mega-thrust events are significantly short in large area corresponding to the size of the mega-thrust events. We also researched cumulative seismic slips after other three mega-thrust earthquakes occurred in this 100 years, the 1952 Kamchatka (Mw9.0), the 1960 Chile (Mw9.5), the 1964 Alaska (Mw9.2). The cumulative slips have been significantly short in and around the focal area after their occurrence. The result should reflect persistency of the strong or/and large inter-plate coupled area capable of mega-thrust earthquakes. We applied the same procedure to global subduction zones to find that 21 regions including the focal area of above mega-thrust earthquakes show slip deficit over large area corresponding to the size of M9-class earthquakes. Considering that at least six M9-class earthquakes occurred in this 100 years and each recurrence interval should be 500-1000 years, it would not be surprised that from five to ten times of the already known regions (30 to 60 regions) are capable of M9 class earthquakes. The 21 regions as expected M9 class focal areas in our study is less than 5 to 10 times of the known 6, some of these regions may be divided into a few M9 class focal area because they extend to much larger area than typical M9 class focal area.

Dispersion and sampling of adult Dermacentor andersoni in rangeland in Western North America.

PubMed

Rochon, K; Scoles, G A; Lysyk, T J

2012-03-01

A fixed precision sampling plan was developed for off-host populations of adult Rocky Mountain wood tick, Dermacentor andersoni (Stiles) based on data collected by dragging at 13 locations in Alberta, Canada; Washington; and Oregon. In total, 222 site-date combinations were sampled. Each site-date combination was considered a sample, and each sample ranged in size from 86 to 250 10 m2 quadrats. Analysis of simulated quadrats ranging in size from 10 to 50 m2 indicated that the most precise sample unit was the 10 m2 quadrat. Samples taken when abundance < 0.04 ticks per 10 m2 were more likely to not depart significantly from statistical randomness than samples taken when abundance was greater. Data were grouped into ten abundance classes and assessed for fit to the Poisson and negative binomial distributions. The Poisson distribution fit only data in abundance classes < 0.02 ticks per 10 m2, while the negative binomial distribution fit data from all abundance classes. A negative binomial distribution with common k = 0.3742 fit data in eight of the 10 abundance classes. Both the Taylor and Iwao mean-variance relationships were fit and used to predict sample sizes for a fixed level of precision. Sample sizes predicted using the Taylor model tended to underestimate actual sample sizes, while sample sizes estimated using the Iwao model tended to overestimate actual sample sizes. Using a negative binomial with common k provided estimates of required sample sizes closest to empirically calculated sample sizes.

Crew behavior and performance in space analog environments

NASA Technical Reports Server (NTRS)

Kanki, Barbara G.

1992-01-01

The objectives and the current status of the Crew Factors research program conducted at NASA-Ames Research Center are reviewed. The principal objectives of the program are to determine the effects of a broad class of input variables on crew performance and to provide guidance with respect to the design and management of crews assigned to future space missions. A wide range of research environments are utilized, including controlled experimental settings, high fidelity full mission simulator facilities, and fully operational field environments. Key group processes are identified, and preliminary data are presented on the effect of crew size, type, and structure on team performance.

Size Class Distribution of Quercus engelmannii (Engelmann Oak) on the Santa Rosa Plateau, Riverside County, California

Treesearch

Earl W. Lathrop; Chris Osborne; Anna Rochester; Kevin Yeung; Samuel Soret; Rochelle Hopper

1991-01-01

Size class distribution of Quercus engelmannii (Engelmann oak) on the Santa Rosa Plateau was studied to understand whether current recruitment of young oaks is sufficient to maintain the population in spite of high natural mortality and impacts of development in some portions of the plateau woodland. Sapling-size oaks (1-10 cm dbh) made up 5.56 pct...

A General Class of Signed Rank Tests for Clustered Data when the Cluster Size is Potentially Informative

PubMed Central

Datta, Somnath; Nevalainen, Jaakko; Oja, Hannu

2012-01-01

SUMMARY Rank based tests are alternatives to likelihood based tests popularized by their relative robustness and underlying elegant mathematical theory. There has been a serge in research activities in this area in recent years since a number of researchers are working to develop and extend rank based procedures to clustered dependent data which include situations with known correlation structures (e.g., as in mixed effects models) as well as more general form of dependence. The purpose of this paper is to test the symmetry of a marginal distribution under clustered data. However, unlike most other papers in the area, we consider the possibility that the cluster size is a random variable whose distribution is dependent on the distribution of the variable of interest within a cluster. This situation typically arises when the clusters are defined in a natural way (e.g., not controlled by the experimenter or statistician) and in which the size of the cluster may carry information about the distribution of data values within a cluster. Under the scenario of an informative cluster size, attempts to use some form of variance adjusted sign or signed rank tests would fail since they would not maintain the correct size under the distribution of marginal symmetry. To overcome this difficulty Datta and Satten (2008; Biometrics, 64, 501–507) proposed a Wilcoxon type signed rank test based on the principle of within cluster resampling. In this paper we study this problem in more generality by introducing a class of valid tests employing a general score function. Asymptotic null distribution of these tests is obtained. A simulation study shows that a more general choice of the score function can sometimes result in greater power than the Datta and Satten test; furthermore, this development offers the user a wider choice. We illustrate our tests using a real data example on spinal cord injury patients. PMID:23074359

A General Class of Signed Rank Tests for Clustered Data when the Cluster Size is Potentially Informative.

PubMed

Datta, Somnath; Nevalainen, Jaakko; Oja, Hannu

2012-09-01

Rank based tests are alternatives to likelihood based tests popularized by their relative robustness and underlying elegant mathematical theory. There has been a serge in research activities in this area in recent years since a number of researchers are working to develop and extend rank based procedures to clustered dependent data which include situations with known correlation structures (e.g., as in mixed effects models) as well as more general form of dependence.The purpose of this paper is to test the symmetry of a marginal distribution under clustered data. However, unlike most other papers in the area, we consider the possibility that the cluster size is a random variable whose distribution is dependent on the distribution of the variable of interest within a cluster. This situation typically arises when the clusters are defined in a natural way (e.g., not controlled by the experimenter or statistician) and in which the size of the cluster may carry information about the distribution of data values within a cluster.Under the scenario of an informative cluster size, attempts to use some form of variance adjusted sign or signed rank tests would fail since they would not maintain the correct size under the distribution of marginal symmetry. To overcome this difficulty Datta and Satten (2008; Biometrics, 64, 501-507) proposed a Wilcoxon type signed rank test based on the principle of within cluster resampling. In this paper we study this problem in more generality by introducing a class of valid tests employing a general score function. Asymptotic null distribution of these tests is obtained. A simulation study shows that a more general choice of the score function can sometimes result in greater power than the Datta and Satten test; furthermore, this development offers the user a wider choice. We illustrate our tests using a real data example on spinal cord injury patients.

[Effects of forest gap size on the growth and form quality of Taxus wallichina var. mairei in Cunninghamia lanceolata forests].

PubMed

Ou, Jian de; Wu, Zhi Zhuang; Luo, Ning

2016-10-01

In order to clarify the effects of forest gap size on the growth and stem form quality of Taxus wallichina var. mairei and effectiveness of the precious timbers cultivation, 25 sample plots in Cunninghamia lanceolata forest gaps were established in Mingxi County, Fujian Province, China to determine the indices of the growth, stem form and branching indices of T. wallichina var. mairei seedlings. The relationships between the gap size and growth, stem form and branching were investigated. The 25 sample plots were located at five microhabitats which were classified based on gap size as follows: Class1, 2, 3, 4 and 5, which had a gap size of 25-50 m 2 , 50-75 m 2 , 75-100 m 2 , 100-125 m 2 and 125-150 m 2 , respectively. The evaluation index system of precious timbers was built by using hierarchical analysis. The 5 classes of forest gaps were evaluated comprehensively by using the multiobjective decision making method. The results showed that gap size significantly affected 11 indices, i.e., height, DBH, crown width, forking rate, stem straightness, stem fullness, taperingness, diameter height ratio, height under living branch, interval between branches, and max-branch base diameter. Class1and 2 both significantly promoted the growth of height, DBH and crown width, and both significantly inhibited forking rate and taperingness, and improved stem straightness. Class2 significantly improved stem fullness and diameter height ratio. Class1and 2 significantly improved height under living branch and reduced max-branch base diameter. Class 1 significantly increased interval between branches. Class1and2 significantly improved the comprehensive evaluation score of precious timbers. This study suggested that controlled cutting intensity could be used to create forest gaps of 25-75 m 2 , which improved the precious timber cultivating process of T. wallichina var. mairei in C. lanceolata forests.

POM Pulses: Characterizing the Physical and Chemical Properties of Particulate Organic Matter (POM) Mobilized by Large Storm Events and its Influence on Receiving Fluvial Systems

NASA Astrophysics Data System (ADS)

Johnson, E. R.; Rowland, R. D.; Protokowicz, J.; Inamdar, S. P.; Kan, J.; Vargas, R.

2016-12-01

Extreme storm events have tremendous erosive energy which is capable of mobilizing vast amounts of material from watershed sources into fluvial systems. This complex mixture of sediment and particulate organic matter (POM) is a nutrient source, and has the potential to impact downstream water quality. The impact of POM on receiving aquatic systems can vary not only by the total amount exported but also by the various sources involved and the particle sizes of POM. This study examines the composition of POM in potential sources and within-event POM by: (1) determining the amount and quality of dissolved organic matter (DOM) that can be leached from coarse, medium and fine particle classes; (2) assessing the C and N content and isotopic character of within-event POM; and (3) coupling physical and chemical properties to evaluate storm event POM influence on stream water. Storm event POM samples and source sediments were collected from a forested headwater catchment (second order stream) in the Piedmont region of Maryland. Samples were sieved into three particle classes - coarse (2mm-1mm), medium (1mm-250µm) and fine (<250µm). Extractions were performed for three particle class sizes and the resulting fluorescent organic matter was analyzed. Carbon (C) and Nitrogen (N) amount, C:N ratio, and isotopic analysis of 13C and 15N were performed on solid state event and source material. Future work will include examination of microbial communities associated with POM particle size classes. Physical size class separation of within-event POM exhibited differences in C:N ratios, δ15N composition, and extracted DOM lability. Smaller size classes exhibited lower C:N ratios, more enriched δ15N and more recalcitrant properties in leached DOM. Source material had varying C:N ratios and contributions to leached DOM. These results indicate that both source and size class strongly influence the POM contribution to fluvial systems during large storm events.

49 CFR 175.704 - Plutonium shipments.

Code of Federal Regulations, 2010 CFR

2010-10-01

... lower cargo compartment in the aft-most location that is possible for cargo of its size and weight, and... aboard an aircraft carrying other cargo required to bear any of the following labels: Class 1 (all Divisions), Class 2 (all Divisions), Class 3, Class 4 (all Divisions), Class 5 (all Divisions), or Class 8...

Harvesting, predation and competition effects on a red coral population

NASA Astrophysics Data System (ADS)

Abbiati, M.; Buffoni, G.; Caforio, G.; Di Cola, G.; Santangelo, G.

A Corallium rubrum population, dwelling in the Ligurian Sea, has been under observation since 1987. Biometric descriptors of colonies (base diameter, weight, number of polyps, number of growth rings) have been recorded and correlated. The population size structure was obtained by distributing the colonies into diameter classes, each size class representing the average annual increment of diameter growth. The population was divided into ten classes, including a recruitment class. This size structure showed a fairly regular trend in the first four classes. The irregularity of survival in the older classes agreed with field observations on harvesting and predation. Demographic parameters such as survival, growth plasticity and natality coefficients were estimated from the experimental data. On this basis a discrete nonlinear model was implemented. The model is based on a kind of density-dependent Leslie matrix, where the feedback term only occurs in survival of the first class; the recruitment function is assumed to be dependent on the total biomass and related to inhibiting effects due to competitive interactions. Stability analysis was applied to steady-state solutions. Numerical simulations of population evolution were carried out under different conditions. The dynamics of settlement and the effects of disturbances such as harvesting, predation and environmental variability were studied.

Small benthic size classes along the N.W. European Continental Margin: spatial and temporal variability in activity and biomass

NASA Astrophysics Data System (ADS)

Pfannkuche, O.; Soltwedel, T.

1998-12-01

In the context of the European OMEX Programme this investigation focused on gradients in the biomass and activity of the small benthic size spectrum along a transect across the Goban Spur from the outer Celtic Sea into Porcupine Abyssal Plain. The effects of food pulses (seasonal, episodic) on this part of the benthic size spectrum were investigated. Sediments sampled during eight expeditions at different seasons covering a range from 200 m to 4800 m water depth were assayed with biochemical bulk measurements: determinations of chloroplastic pigment equivalents (CPE), the sum of chlorophyll a and its breakdown products, provide information concerning the input of phytodetrital matter to the seafloor; phospholipids were analyzed to estimate the total biomass of small benthic organisms (including bacteria, fungi, flagellata, protozoa and small metazoan meiofauna). A new term `small size class biomass' (SSCB) is introduced for the biomass of the smallest size classes of sediment-inhabiting organisms; the reduction of fluorescein-di-acetate (FDA) was determined to evaluate the potential activity of ester-cleaving bacterial exoenzymes in the sediment samples. At all stations benthic biomass was predominantly composed of the small size spectrum (90% on the shelf; 97-98% in the bathyal and abyssal parts of the transect). Small size class biomass (integrated over a 10 cm sediment column) ranged from 8 g C m -2 on the shelf to 2.1 g C m -2 on the adjacent Porcupine Abyssal Plain, exponentially decreasing with increasing water depth. However, a correlation between water depth and SSCB, macrofauna biomass as well as metazoan meiofauna biomass exhibited a significantly flatter slope for the small size classes in comparison to the larger organisms. CPE values indicated a pronounced seasonal cycle on the shelf and upper slope with twin peaks of phytodetrital deposition in mid spring and late summer. The deeper stations seem to receive a single annual flux maximum in late summer. SSCB and heterotrophic activity are significantly correlated to the amount of sediment-bound pigments. Seasonality in pigment concentrations is clearly followed by SSCB and activity. In contrast to macro- and megafauna which integrate over larger periods (months/years), the small benthic size classes, namely bacteria and foraminifera, proved to be the most reactive potential of the benthic communities to any perturbations on short time scales (days/weeks). The small size classes, therefore, occupy a key role in early diagenetic processes.

Quantifying Grain-Size Variability of Metal Pollutants in Road-Deposited Sediments Using the Coefficient of Variation

PubMed Central

Wang, Xiaoxue; Li, Xuyong

2017-01-01

Particle grain size is an important indicator for the variability in physical characteristics and pollutants composition of road-deposited sediments (RDS). Quantitative assessment of the grain-size variability in RDS amount, metal concentration, metal load and GSFLoad is essential to elimination of the uncertainty it causes in estimation of RDS emission load and formulation of control strategies. In this study, grain-size variability was explored and quantified using the coefficient of variation (Cv) of the particle size compositions, metal concentrations, metal loads, and GSFLoad values in RDS. Several trends in grain-size variability of RDS were identified: (i) the medium class (105–450 µm) variability in terms of particle size composition, metal loads, and GSFLoad values in RDS was smaller than the fine (<105 µm) and coarse (450–2000 µm) class; (ii) The grain-size variability in terms of metal concentrations increased as the particle size increased, while the metal concentrations decreased; (iii) When compared to the Lorenz coefficient (Lc), the Cv was similarly effective at describing the grain-size variability, whereas it is simpler to calculate because it did not require the data to be pre-processed. The results of this study will facilitate identification of the uncertainty in modelling RDS caused by grain-size class variability. PMID:28788078

A population model for a long-lived, resprouting chaparral shrub: Adenostoma fasciculatum

USGS Publications Warehouse

Stohlgren, Thomas J.; Rundel, Philip W.

1986-01-01

Extensive stands of Adenostoma fasciculatum H.&A. (chamise) in the chaparral of California are periodically rejuvenated by fire. A population model based on size-specific demographic characteristics (thinning and fire-caused mortality) was developed to generate probable age distributions within size classes and survivorship curves for typical stands. The model was modified to assess the long term effects of different mortality rates on age distributions. Under observed mean mortality rates (28.7%), model output suggests some shrubs can survive more than 23 fires. A 10% increase in mortality rate by size class slightly shortened the survivorship curve, while a 10% decrease in mortality rate by size class greatly elongated the curve. This approach may be applicable to other long-lived plant species with complex life histories.

The effect of sample size and disease prevalence on supervised machine learning of narrative data.

PubMed Central

McKnight, Lawrence K.; Wilcox, Adam; Hripcsak, George

2002-01-01

This paper examines the independent effects of outcome prevalence and training sample sizes on inductive learning performance. We trained 3 inductive learning algorithms (MC4, IB, and Naïve-Bayes) on 60 simulated datasets of parsed radiology text reports labeled with 6 disease states. Data sets were constructed to define positive outcome states at 4 prevalence rates (1, 5, 10, 25, and 50%) in training set sizes of 200 and 2,000 cases. We found that the effect of outcome prevalence is significant when outcome classes drop below 10% of cases. The effect appeared independent of sample size, induction algorithm used, or class label. Work is needed to identify methods of improving classifier performance when output classes are rare. PMID:12463878

Test Operation Procedure (TOP) 01-1-010A Vehicle Test Course Severity (Surface Roughness)

DTIC Science & Technology

2017-12-12

Department of Agriculture (USDA) classifications, respectively. TABLE 10. PARTICLE SIZE CLASSES CLASS SIZE Cobble and Gravel >4.75 mm particle diameter...ABBREVIATIONS. USCS Unified Soil Classification System USDA United States Department of Agriculture UTM Universal Transverse Mercator WNS wave number

Montane conifer fuel dynamics, Yosemite National Park

USGS Publications Warehouse

van Wagtendonk, J.W.; Moore, P.E.

1997-01-01

Litter and woody fuel accumulation rates over 7 years for 7 montane Sierra Nevada conifer species, including giant sequoia, ponderosa pine, sugar pine, Jeffrey pine, incense-cedar and white fir. Data are from four sites per size class per species with four size classes each. Nonspatial, georeferenced.

Louisiana forests: Status and outlook

Treesearch

Paul A. Murphy

1975-01-01

Between 1964 and 1974, forest area in Louisiana declined 9 percent to 14.5 million acres. Softwood volume increased 31 percent to 9 billion cubic feet, and hardwood declined 7 percent to 7.7 billion. All softwood size classes had increases in volume, and all hardwood size classes had decreases.

Migration Patterns, Densities, and Growth of Neritina punctulata Snails in Rio Espiritu Santo and Rio Mameyes, Northeastern Puerto Rico.

Treesearch

MARK PYRON; ALAN P. COVICH

2003-01-01

Snail size-frequency distributions in Rios Espiritu Santo and Mameyes, which drain the Luquillo Experimental Forest, Puerto Rico, showed that Neritina punctulata with shell lengths greater than 30 mm were the most abundant size class at upstream sites. The highest densities for all size classes were at the downstream sites. Growth rates were 0.015 mm/day for a large...

Phosphorus content as a function of soil aggregate size and paddy cultivation in highly weathered soils.

PubMed

Li, Baozhen; Ge, Tida; Xiao, Heai; Zhu, Zhenke; Li, Yong; Shibistova, Olga; Liu, Shoulong; Wu, Jinshui; Inubushi, Kazuyuki; Guggenberger, Georg

2016-04-01

Red soils are the major land resource in subtropical and tropical areas and are characterized by low phosphorus (P) availability. To assess the availability of P for plants and the potential stability of P in soil, two pairs of subtropical red soil samples from a paddy field and an adjacent uncultivated upland were collected from Hunan Province, China. Analysis of total P and Olsen P and sequential extraction was used to determine the inorganic and organic P fractions in different aggregate size classes. Our results showed that the soil under paddy cultivation had lower proportions of small aggregates and higher proportions of large aggregates than those from the uncultivated upland soil. The portion of >2-mm-sized aggregates increased by 31 and 20 % at Taoyuan and Guiyang, respectively. The total P and Olsen P contents were 50-150 and 50-300 % higher, respectively, in the paddy soil than those in the upland soil. Higher inorganic and organic P fractions tended to be enriched in both the smallest and largest aggregate size classes compared to the middle size class (0.02-0.2 mm). Furthermore, the proportion of P fractions was higher in smaller aggregate sizes (<2 mm) than in the higher aggregate sizes (>2 mm). In conclusion, soils under paddy cultivation displayed improved soil aggregate structure, altered distribution patterns of P fractions in different aggregate size classes, and to some extent had enhanced labile P pools.

Meeting the Public Health Challenge of Pain in Later Life: What Role Can Senior Centers Play?

PubMed Central

Tobias, Karen R.; Lama, Sonam D.; Parker, Samantha J.; Henderson, Charles R.; Nickerson, Allison J.; Reid, M.C.

2013-01-01

Background Interest in nonpharmacologic approaches for managing pain continues to grow. Aim To determine the types of pain-relevant programs offered by senior centers and whether the programs varied by clients' race/ethnicity status and center size. Design and methods We conducted a telephone survey. Respondents were presented with a list of 15 programs (plus other) and asked: (1) whether the activity was offered and if so how often; (2) if they believed the programs had value for seniors with pain; and (3) whether the classes were advertised as a means of achieving pain relief. Setting New York City. Participants/Subjects Senior center agency staff, i.e., center directors, activity program coordinators. Results Of 204 center staff contacted, 195 (95.6%) participated. The most common programs offered were movement-based, including exercise (by 91.8% of the centers), dance (72.3%), walking clubs (71.8%), yoga (65.6%), and Tai Chi (53.3%) classes. Creative arts programs were also frequently offered, including music (58.5%) and fine arts (47.7%). Programs such as stress management (27%) and relaxation (26%) classes were less commonly offered. Most respondents identified movement-based programs as helpful for seniors with pain, while few identified creative arts classes as potentially beneficial. The programs/classes offered were infrequently advertised as a means of helping seniors manage pain, and varied by clients' race/ethnicity status and center size. Conclusion Programs that have potential utility for older adults with pain are commonly offered by senior centers. Future research should determine optimal strategies for engaging older adults in these programs in the senior center setting. PMID:24144569

Latent Classes of Substance Use Among American Indian and White Students Living on or Near Reservations, 2009-2013.

PubMed

Stanley, Linda R; Swaim, Randall C

2018-01-01

American Indian adolescents who reside on or near reservations report higher levels of substance use than adolescents in other racial/ethnic groups. Little research has addressed patterns of use, which have important implications for prevention and treatment planning. The objective of our study was to describe substance use among a large, population-based sample of American Indian and white students who lived on or near reservations. We obtained data from 4964 students in grades 7-12 attending 46 schools on or near reservations throughout the United States during 4 academic years (2009-2013). Measures assessed current substance use for alcohol, heavy drinking, marijuana, cigarettes, inhalants, and other drugs. We used latent class analysis to identify patterns of substance use by grade group (grades 7-8 and grades 9-12) and race (American Indian or white). For American Indians in both grade groups, we found 4 classes of substance use (in order of size): (1) nonusers; (2) marijuana and cigarette users; (3) alcohol, marijuana, and cigarette users; and (4) polysubstance users. For white students, we found 2 classes (nonusers and polysubstance users) among younger students and 4 classes (nonusers; alcohol, marijuana, and cigarette users; alcohol and cigarette users; and polysubstance users) among older students. We found significant differences in substance use patterns, especially at younger ages, between reservation American Indian students and white students attending the same schools. Combinations of substances used by American Indian adolescents were most likely to include marijuana, as compared with alcohol for white adolescents. Identifying subpopulations of users allows the design of interventions that will more efficiently and effectively address prevention and treatment needs of groups of individuals than would a one-size-fits-all approach.

Meeting the public health challenge of pain in later life: what role can senior centers play?

PubMed

Tobias, Karen R; Lama, Sonam D; Parker, Samantha J; Henderson, Charles R; Nickerson, Allison J; Reid, M Carrington

2014-12-01

Interest in nonpharmacologic approaches for managing pain continues to grow. The aim of this study was to determine the types of pain-relevant programs offered by senior centers and whether the programs varied by clients' race/ethnicity status and center size. A telephone survey was conducted. Respondents were presented with a list of 15 programs and the option to choose "other" and asked (1) whether the activity was offered and, if so, how often; (2) if they believed the programs had value for seniors with pain; and (3) whether the classes were advertised as a means of achieving pain relief. Of 204 center staff contacted, 195 (95.6%) participated. The most common programs offered were movement-based, including exercise (by 91.8% of the centers), dance (72.3%), walking clubs (71.8%), yoga (65.6%), and Tai Chi (53.3%) classes. Creative arts programs were also frequently offered, including music (58.5%) and fine arts (47.7%). Programs such as stress management (27%) and relaxation (26%) classes were less commonly offered. Most respondents identified movement-based programs as helpful for seniors with pain, but few identified creative arts classes as potentially beneficial. The programs/classes offered were infrequently advertised as a means of helping seniors manage pain and varied by clients' race/ethnicity status and center size. Programs that have potential utility for older adults with pain are commonly offered by senior centers. Future research should determine optimal strategies for engaging older adults in these programs in the senior center setting. Copyright © 2014 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

Transcriptome assembly and candidate genes involved in nutritional programming in the swordtail fish Xiphophorus multilineatus.

PubMed

Lu, Yuan; Klimovich, Charlotte M; Robeson, Kalen Z; Boswell, William; Ríos-Cardenas, Oscar; Walter, Ronald B; Morris, Molly R

2017-01-01

Nutritional programming takes place in early development. Variation in the quality and/or quantity of nutrients in early development can influence long-term health and viability. However, little is known about the mechanisms of nutritional programming. The live-bearing fish Xiphophorus multilineatus has the potential to be a new model for understanding these mechanisms, given prior evidence of nutritional programming influencing behavior and juvenile growth rate. We tested the hypotheses that nutritional programming would influence behaviors involved in energy homeostasis as well gene expression in X. multilineatus. We first examined the influence of both juvenile environment (varied in nutrition and density) and adult environment (varied in nutrition) on behaviors involved in energy acquisition and energy expenditure in adult male X. multilineatus . We also compared the behavioral responses across the genetically influenced size classes of males. Males stop growing at sexual maturity, and the size classes of can be identified based on phenotypes (adult size and pigment patterns). To study the molecular signatures of nutritional programming, we assembled a de novo transcriptome for X. multilineatus using RNA from brain, liver, skin, testis and gonad tissues, and used RNA-Seq to profile gene expression in the brains of males reared in low quality (reduced food, increased density) and high quality (increased food, decreased density) juvenile environments. We found that both the juvenile and adult environments influenced the energy intake behavior, while only the adult environment influenced energy expenditure. In addition, there were significant interactions between the genetically influenced size classes and the environments that influenced energy intake and energy expenditure, with males from one of the four size classes (Y-II) responding in the opposite direction as compared to the other males examined. When we compared the brains of males of the Y-II size class reared in a low quality juvenile environment to males from the same size class reared in high quality juvenile environment, 131 genes were differentially expressed, including metabolism and appetite master regulator agrp gene. Our study provides evidence for nutritional programming in X. multilineatus , with variation across size classes of males in how juvenile environment and adult diet influences behaviors involved in energy homeostasis. In addition, we provide the first transcriptome of X. multilineatus , and identify a group of candidate genes involved in nutritional programming.

Sella size and jaw bases - Is there a correlation???

PubMed

Neha; Mogra, Subraya; Shetty, Vorvady Surendra; Shetty, Siddarth

2016-01-01

Sella turcica is an important cephalometric structure and attempts have been made in the past to correlate its dimensions to the malocclusion. However, no study has so far compared the size of sella to the jaw bases that determine the type of malocclusion. The present study was undertaken to find out any such correlation if it exists. Lateral cephalograms of 110 adults consisting of 40 Class I, 40 Class II, and 30 Class III patients were assessed for the measurement of sella length, width, height, and area. The maxillary length, mandibular ramus height, and body length were also measured. The sella dimensions were compared among three malocclusion types by one-way ANOVA. Pearson correlation was calculated between the jaw size and sella dimensions. Furthermore, the ratio of jaw base lengths and sella area were calculated. Mean sella length, width and area were found to be greatest in Class III, followed by Class I and least in Class II though the results were not statistically significant. 3 out of 4 measured dimensions of sella, correlated significantly with mandibular ramus and body length each. However, only one dimension of sella showed significant correlation with maxilla. The mandibular ramus and body length show a nearly constant ratio to sella area (0.83-0.85, 0.64-0.65, respectively) in all the three malocclusions. Thus, mandible has a definite and better correlation to the size of sella turcica.

California's Class Size Reduction: Implications for Equity, Practice & Implementation.

ERIC Educational Resources Information Center

Wexler, Edward; Izu, JoAnn; Carlos, Lisa; Fuller, Bruce; Hayward, Gerald; Kirst, Mike

When California implemented its class-size reduction (CSR) program in 1996, a number of questions regarding financial burdens, teacher shortages, scarcity of facilities, and collective bargaining were raised. This first-year implementation study aims to provide some contextual information as background for answering questions, to clarify these…

Effects of Class Size on Alternative Educational Outcomes across Disciplines

ERIC Educational Resources Information Center

Cheng, Dorothy A.

2011-01-01

This is the first study to use self-reported ratings of student learning, instructor recommendations, and course recommendations as the outcome measure to estimate class size effects, doing so across 24 disciplines. Fixed-effects models controlling for heterogeneous courses and instructors reveal that increasing enrollment has negative and…

78 FR 42817 - Small Business Size Standards: Waiver of the Nonmanufacturer Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-17

... SMALL BUSINESS ADMINISTRATION Small Business Size Standards: Waiver of the Nonmanufacturer Rule AGENCY: U.S. Small Business Administration. ACTION: Notice of intent to rescind the class waiver of the... Manufacturing. SUMMARY: The U. S. Small Business Administration (SBA) intends to rescind a class waiver of the...

Sizing Up What Matters.

ERIC Educational Resources Information Center

McCluskey, Neal

"Smaller is better" is often the mantra of school leaders with regard to class size, while the benefits of smaller schools are ignored. Benefits of small classes seem obvious--teachers with fewer students could devote more time to each student. Conducted in 1985-89, Tennessee's Project STAR (Student/Teacher Achievement Ratio) found that…

Influences of Teaching Approaches and Class Size on Undergraduate Mathematical Learning

ERIC Educational Resources Information Center

Olson, Jo Clay; Cooper, Sandy; Lougheed, Tom

2011-01-01

An issue for many mathematics departments is the success rate of precalculus students. In an effort to increase the success rate, this quantitative study investigated how class size and teaching approach influenced student achievement and students' attitudes towards learning mathematics. Students' achievement and their attitudes toward learning…

Educational Production and Teacher Preferences

ERIC Educational Resources Information Center

Bosworth, Ryan; Caliendo, Frank

2007-01-01

We develop a simple model of teacher behavior that offers a solution to the ''class size puzzle'' and is useful for analyzing the potential effects of the No Child Left Behind Act. When teachers must allocate limited classroom time between multiple instructional methods, rational teachers may respond to reductions in class size by reallocating…

Empirically derived lifespan polytraumatization typologies: A systematic review.

PubMed

Contractor, Ateka A; Caldas, Stephanie; Fletcher, Shelley; Shea, M Tracie; Armour, Cherie

2018-07-01

Polytraumatization classes based on trauma endorsement patterns relate to distinct clinical outcomes. Person-centered approaches robustly evaluate the nature, and construct validity of polytraumatization classes. Our review examined evidence for the nature and construct validity of lifespan polytraumatization typologies. In September 2016, we searched Pubmed, PSYCINFO, PSYC ARTICLES, Academic Search Complete, PILPTS, Web of Science, CINAHL, Medline, PsycEXTRA, and PBSC. Search terms included "latent profile," "latent class," "latent analysis," "person-centered," "polytrauma," "polyvictimization," "traumatization," "lifetime," "cooccurring," "complex," "typology," "multidimensional," "sequential," "multiple," "subtype," "(re)victimization," "cumulative," "maltreatment," "abuse," and "stressor." Inclusionary criteria included: peer-reviewed; latent class/latent profile analyses (LCA/LPA) of lifespan polytrauma classes; adult samples of size greater than 200; only trauma types as LCA/LPA indicators; mental health correlates of typologies; and individual-level trauma assessment. Of 1,397 articles, nine met inclusion criteria. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, research assistants completed a secondary reference search, and independently extracted data with standardized coding forms. Three-class (n = 5) or four-class (n = 4) solutions were found. Seven studies found a class characterized by higher trauma endorsement (high-trauma). All studies found a class characterized by lower trauma endorsement (low-trauma), and predominance of specific traumas (specific-trauma; e.g., childhood maltreatment). High-trauma versus low-trauma classes and specific-trauma versus low-trauma classes differed on mental health correlates. Evidence supports the prevalence of a high-trauma class experiencing poorer mental health, and the detrimental impact of aggregated interpersonal and other traumas. We highlight the clinical importance of addressing polytraumatization classes, and comprehensively assessing the impact of all traumas. © 2018 Wiley Periodicals, Inc.

Improved Soil Erosion and Sediment Transport in GSSHA

DTIC Science & Technology

2010-08-01

the USLE soil erodibility factor (0-1), soil cropping factor (0-1) and conservation factor (0-1) in the development by Julien (1995). The use of one...factor K represents a departure from Julien (1995), who used all three factors from the Universal Soil Loss Equation ( USLE ). This departure is justi...runoff using a research-quality data set. BACKGROUND: GSSHA simulates overland soil erosion and outputs erosion and deposition for any size class of

Preferential attachment and growth dynamics in complex systems

NASA Astrophysics Data System (ADS)

Yamasaki, Kazuko; Matia, Kaushik; Buldyrev, Sergey V.; Fu, Dongfeng; Pammolli, Fabio; Riccaboni, Massimo; Stanley, H. Eugene

2006-09-01

Complex systems can be characterized by classes of equivalency of their elements defined according to system specific rules. We propose a generalized preferential attachment model to describe the class size distribution. The model postulates preferential growth of the existing classes and the steady influx of new classes. According to the model, the distribution changes from a pure exponential form for zero influx of new classes to a power law with an exponential cut-off form when the influx of new classes is substantial. Predictions of the model are tested through the analysis of a unique industrial database, which covers both elementary units (products) and classes (markets, firms) in a given industry (pharmaceuticals), covering the entire size distribution. The model’s predictions are in good agreement with the data. The paper sheds light on the emergence of the exponent τ≈2 observed as a universal feature of many biological, social and economic problems.

Hierarchical zeolites from class F coal fly ash

NASA Astrophysics Data System (ADS)

Chitta, Pallavi

Fly ash, a coal combustion byproduct is classified as types class C and class F. Class C fly ash is traditionally recycled for concrete applications and Class F fly ash often disposed in landfills. Class F poses an environmental hazard due to disposal and leaching of heavy metals into ground water and is important to be recycled in order to mitigate the environmental challenges. A major recycling option is to reuse the fly ash as a low-cost raw material for the production of crystalline zeolites, which serve as catalysts, detergents and adsorbents in the chemical industry. Most of the prior literature of fly ash conversion to zeolites does not focus on creating high zeolite surface area zeolites specifically with hierarchical pore structure, which are very important properties in developing a heterogeneous catalyst for catalysis applications. This research work aids in the development of an economical process for the synthesis of high surface area hierarchical zeolites from class F coal fly ash. In this work, synthesis of zeolites from fly ash using classic hydrothermal treatment approach and fusion pretreatment approach were examined. The fusion pretreatment method led to higher extent of dissolution of silica from quartz and mullite phases, which in turn led to higher surface area and pore size of the zeolite. A qualitative kinetic model developed here attributes the difference in silica content to Si/Al ratio of the beginning fraction of fly ash. At near ambient crystallization temperatures and longer crystallization times, the zeolite formed is a hierarchical faujasite with high surface area of at least 360 m2/g. This work enables the large scale recycling of class F coal fly ash to produce zeolites and mitigate environmental concerns. Design of experiments was used to predict surface area and pore sizes of zeolites - thus obviating the need for intense experimentation. The hierarchical zeolite catalyst supports tested for CO2 conversion, yielded hydrocarbons up to C9, a performance attesting the hierarchal pore structure. The preliminary techno-economic feasibility assessment demonstrates a net energy saving of 75% and cost saving of 63% compared to the commercial zeolite manufacturing process.

Characterization of swine leukocyte antigen alleles and haplotypes on a novel miniature pig line, Microminipig.

PubMed

Ando, A; Imaeda, N; Ohshima, S; Miyamoto, A; Kaneko, N; Takasu, M; Shiina, T; Kulski, J K; Inoko, H; Kitagawa, H

2014-12-01

Microminipigs are extremely small-sized, novel miniature pigs that were recently developed for medical research. The inbred Microminipigs with defined swine leukocyte antigen (SLA) haplotypes are expected to be useful for allo- and xenotransplantation studies and also for association analyses between SLA haplotypes and immunological traits. To establish SLA-defined Microminipig lines, we characterized the polymorphic SLA alleles for three class I (SLA-1, SLA-2 and SLA-3) and two class II (SLA-DRB1 and SLA-DQB1) genes of 14 parental Microminipigs using a high-resolution nucleotide sequence-based typing method. Eleven class I and II haplotypes, including three recombinant haplotypes, were found in the offspring of the parental Microminipigs. Two class I and class II haplotypes, Hp-31.0 (SLA-1*1502-SLA-3*070102-SLA-2*1601) and Hp-0.37 (SLA-DRB1*0701-SLA-DQB1*0502), are novel and have not so far been reported in other pig breeds. Crossover regions were defined by the analysis of 22 microsatellite markers within the SLA class III region of three recombinant haplotypes. The SLA allele and haplotype information of Microminipigs in this study will be useful to establish SLA homozygous lines including three recombinants for transplantation and immunological studies. © 2014 Stichting International Foundation for Animal Genetics.

Effective, Active Learning Strategies for the Oceanography Classroom

NASA Astrophysics Data System (ADS)

Dmochowski, J. E.; Marinov, I.

2014-12-01

A decline in enrollment in STEM fields at the university level has prompted extensive research on alternative ways of teaching and learning science. Inquiry-based learning as well as the related "flipped" or "active" lectures, and similar teaching methods and philosophies have been proposed as more effective ways to disseminate knowledge in science classes than the traditional lecture. We will provide a synopsis of our experiences in implementing some of these practices into our Introductory Oceanography, Global Climate Change, and Ocean Atmosphere Dynamics undergraduate courses at the University of Pennsylvania, with both smaller and larger enrollments. By implementing tools such as at-home modules; computer labs; incorporation of current research; pre- and post-lecture quizzes; reflective, qualitative writing assignments; peer review; and a variety of in-class learning strategies, we aim to increase the science literacy of the student population and help students gain a more comprehensive knowledge of the topic, enhance their critical thinking skills, and correct misconceptions. While implementing these teaching techniques with college students is not without complications, we argue that a blended class that flexibly and creatively accounts for class size and science level improves the learning experience and the acquired knowledge. We will present examples of student assignments and activities as well as describe the lessons we have learned, and propose ideas for moving forward to best utilize innovative teaching tools in order to increase science literacy in oceanography and other climate-related courses.

Note-taking skills of middle school students with and without learning disabilities.

PubMed

Boyle, Joseph R

2010-01-01

For middle school students with learning disabilities (LD), one major component of learning in content area classes, such as science, involves listening to lectures and recording notes. Lecture learning and note-taking are critical skills for students to succeed in these classes. Despite the importance of note-taking skills, no research has been reported on the problems that school-age students with LD encounter when recording notes during science lectures. Using a sample size of 90 middle school students, the performance of students with LD was compared to students with no learning disabilities (NLD). Results found that students with LD performed significantly worse than students with NLD in terms of the type and amount of notes recorded and test performance.

Emerging roles of engineered nanomaterials in the food industry.

PubMed

Morris, V J

2011-10-01

Nanoscience is the study of phenomena and the manipulation of materials at the atomic or molecular level. Nanotechnology involves the design, production and use of structures through control of the size and shape of the materials at the nanometre scale. Nanotechnology in the food sector is an emerging area with considerable research and potential products. There is particular interest in the definition and regulation of engineered nanomaterials. This term covers three classes of nanomaterials: natural and processed nanostructures in foods; particulate nanomaterials metabolized or excreted on digestion; and particulate nanomaterials not broken down on digestion, which accumulate in the body. This review describes examples of these classes and their likely status in the food industry. Copyright © 2011 Elsevier Ltd. All rights reserved.

The Effect of STEM Learning through the Project of Designing Boat Model toward Student STEM Literacy

NASA Astrophysics Data System (ADS)

Tati, T.; Firman, H.; Riandi, R.

2017-09-01

STEM Learning focusses on development of STEM-literate society, the research about implementation of STEM learning to develope students’ STEM literacy is still limited. This study is aimed to examine the effect of implementation STEM learning through the project of designing boat model on students STEM literacy in energy topic. The method of this study was a quasi-experiment with non-randomized pretest-posttest control group design. There were two classes involved, the experiment class used Project Based Learning with STEM approach and control class used Project-Based Learning without STEM approach. A STEM Literacy test instrument was developed to measure students STEM literacy which consists of science literacy, mathematics literacy, and technology-engineering literacy. The analysis showed that there were significant differences on improvement science literacy, mathematics technology-engineering between experiment class and control class with effect size more than 0.8 (large effect). The difference of improvement of STEM literacy between experiment class and control class is caused by the existence of design engineering activity which required students to apply the knowledge from every field of STEM. The challenge that was faced in STEM learning through design engineering activity was how to give the students practice to integrate STEM field in solving the problems. In additional, most of the students gave positive response toward implementation of STEM learning through design boat model project.

NAS Parallel Benchmarks. 2.4

NASA Technical Reports Server (NTRS)

VanderWijngaart, Rob; Biegel, Bryan A. (Technical Monitor)

2002-01-01

We describe a new problem size, called Class D, for the NAS Parallel Benchmarks (NPB), whose MPI source code implementation is being released as NPB 2.4. A brief rationale is given for how the new class is derived. We also describe the modifications made to the MPI (Message Passing Interface) implementation to allow the new class to be run on systems with 32-bit integers, and with moderate amounts of memory. Finally, we give the verification values for the new problem size.

The effects of host size and temperature on the emergence of Echinoparyphium recurvatum cercariae from Lymnaea peregra under natural light conditions.

PubMed

Morley, N J; Adam, M E; Lewis, J W

2010-09-01

The production of cercariae from their snail host is a fundamental component of transmission success in trematodes. The emergence of Echinoparyphium recurvatum (Trematoda: Echinostomatidae) cercariae from Lymnaea peregra was studied under natural sunlight conditions, using naturally infected snails of different sizes (10-17 mm) within a temperature range of 10-29 degrees C. There was a single photoperiodic circadian cycle of emergence with one peak, which correlated with the maximum diffuse sunlight irradiation. At 21 degrees C the daily number of emerging cercariae increased with increasing host snail size, but variations in cercarial emergence did occur between both individual snails and different days. There was only limited evidence of cyclic emergence patterns over a 3-week period, probably due to extensive snail mortality, particularly those in the larger size classes. Very few cercariae emerged in all snail size classes at the lowest temperature studied (10 degrees C), but at increasingly higher temperatures elevated numbers of cercariae emerged, reaching an optimum between 17 and 25 degrees C. Above this range emergence was reduced. At all temperatures more cercariae emerged from larger snails. Analysis of emergence using the Q10 value, a measure of physiological processes over temperature ranges, showed that between 10 and 21 degrees C (approximately 15 degrees C) Q10 values exceeded 100 for all snail size classes, indicating a substantially greater emergence than would be expected for normal physiological rates. From 14 to 25 degrees C (approximately 20 degrees C) cercarial emergence in most snail size classes showed little change in Q10, although in the smallest size class emergence was still substantially greater than the typical Q10 increase expected over this temperature range. At the highest range of 21-29 degrees C (approximately 25 degrees C), Q10 was much reduced. The importance of these results for cercarial emergence under global climate change is discussed.

Reducing Class Size in New York City: Promise vs. Practice

ERIC Educational Resources Information Center

Farrie, Danielle; Johnson, Monete; Lecker, Wendy; Luhm, Theresa

2016-01-01

In the landmark school funding litigation, "Campaign for Fiscal Equity v. State" ("CFE"), the highest Court in New York recognized that reasonable class sizes are an essential element of a constitutional "sound basic education." In response to the rulings in the case, in 2007, the Legislature adopted a law mandating…

Class Size Reduction or Rapid Formative Assessment?: A Comparison of Cost-Effectiveness

ERIC Educational Resources Information Center

Yeh, Stuart S.

2009-01-01

The cost-effectiveness of class size reduction (CSR) was compared with the cost-effectiveness of rapid formative assessment, a promising alternative for raising student achievement. Drawing upon existing meta-analyses of the effects of student-teacher ratio, evaluations of CSR in Tennessee, California, and Wisconsin, and RAND cost estimates, CSR…

Class Size Reduction: Great Hopes, Great Challenges. Policy Brief.

ERIC Educational Resources Information Center

WestEd, San Francisco, CA.

This policy brief examines the benefits and the challenges that accompany class-size reduction (CSR). It suggests that when designing CSR programs, states should carefully assess specific circumstances in their schools as they adopt or modify CSR efforts to avoid the unintended consequences that some programs have experienced. Some of the…

Smart Class-Size Policies for Lean Times. SREB Policy Brief

ERIC Educational Resources Information Center

Gagne, Jeff

2012-01-01

Most states nationwide have had policies for several decades that limit the number of students assigned to public K-12 classrooms. Southern Regional Education Board (SREB) states, led by Tennessee and Texas, spearheaded this effort in the 1980s, and SREB's own "Legislative Briefings" have marked the growth of class-size policies across…

Forest fragmentation of southern U.S. bottomland hardwoods

Treesearch

Victor A. Rudis

1993-01-01

The magnitude and character of forest fragmentation are evaluated for bottomland hardwoods in the southern United States.Fragment size class is significantly associated with the frequency of bottomland hardwood species, stand size and ownership classes, and land use attributes.Differences in the frequency of indicators of multiple values are apparent. Two diverse...

40 CFR 113.4 - Size classes and associated liability limits for fixed onshore oil storage facilities, 1,000...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Size classes and associated liability... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS LIABILITY LIMITS FOR... privity and knowledge of the owner or operator, the following limits of liability are established for...

Two Universality Classes for the Many-Body Localization Transition

NASA Astrophysics Data System (ADS)

Khemani, Vedika; Sheng, D. N.; Huse, David A.

2017-08-01

We provide a systematic comparison of the many-body localization (MBL) transition in spin chains with nonrandom quasiperiodic versus random fields. We find evidence suggesting that these belong to two separate universality classes: the first dominated by "intrinsic" intrasample randomness, and the second dominated by external intersample quenched randomness. We show that the effects of intersample quenched randomness are strongly growing, but not yet dominant, at the system sizes probed by exact-diagonalization studies on random models. Thus, the observed finite-size critical scaling collapses in such studies appear to be in a preasymptotic regime near the nonrandom universality class, but showing signs of the initial crossover towards the external-randomness-dominated universality class. Our results provide an explanation for why exact-diagonalization studies on random models see an apparent scaling near the transition while also obtaining finite-size scaling exponents that strongly violate Harris-Chayes bounds that apply to disorder-driven transitions. We also show that the MBL phase is more stable for the quasiperiodic model as compared to the random one, and the transition in the quasiperiodic model suffers less from certain finite-size effects.

Annual variation in neustonic micro- and meso-plastic particles and zooplankton in the Bay of Calvi (Mediterranean-Corsica).

PubMed

Collignon, Amandine; Hecq, Jean-Henri; Galgani, François; Collard, France; Goffart, Anne

2014-02-15

The annual variation in neustonic plastic particles and zooplankton was studied in the Bay of Calvi (Corsica) between 30 August 2011 and 7 August 2012. Plastic particles were classified into three size classes, small microplastics (0.2-2mm), large microplastics (2-5mm) and mesoplastics (5-10mm). 74% of the 38 samples contained plastic particles of varying composition: e.g. filaments, polystyrene, thin plastic films. An average concentration of 6.2 particles/100 m(2) was observed. The highest abundance values (69 particles/100 m(2)) observed occurred during periods of low offshore wind conditions. These values rose in the same order of magnitude as in previous studies in the North Western Mediterranean. The relationships between the abundance values of the size classes between zooplankton and plastic particles were then examined. The ratio for the intermediate size class (2-5mm) reached 2.73. This would suggest a potential confusion for predators regarding planktonic prey of this size class. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mixture models for estimating the size of a closed population when capture rates vary among individuals

USGS Publications Warehouse

Dorazio, R.M.; Royle, J. Andrew

2003-01-01

We develop a parameterization of the beta-binomial mixture that provides sensible inferences about the size of a closed population when probabilities of capture or detection vary among individuals. Three classes of mixture models (beta-binomial, logistic-normal, and latent-class) are fitted to recaptures of snowshoe hares for estimating abundance and to counts of bird species for estimating species richness. In both sets of data, rates of detection appear to vary more among individuals (animals or species) than among sampling occasions or locations. The estimates of population size and species richness are sensitive to model-specific assumptions about the latent distribution of individual rates of detection. We demonstrate using simulation experiments that conventional diagnostics for assessing model adequacy, such as deviance, cannot be relied on for selecting classes of mixture models that produce valid inferences about population size. Prior knowledge about sources of individual heterogeneity in detection rates, if available, should be used to help select among classes of mixture models that are to be used for inference.

Three tiers of genome evolution in reptiles

PubMed Central

Organ, Chris L.; Moreno, Ricardo Godínez; Edwards, Scott V.

2008-01-01

Characterization of reptilian genomes is essential for understanding the overall diversity and evolution of amniote genomes, because reptiles, which include birds, constitute a major fraction of the amniote evolutionary tree. To better understand the evolution and diversity of genomic characteristics in Reptilia, we conducted comparative analyses of online sequence data from Alligator mississippiensis (alligator) and Sphenodon punctatus (tuatara) as well as genome size and karyological data from a wide range of reptilian species. At the whole-genome and chromosomal tiers of organization, we find that reptilian genome size distribution is consistent with a model of continuous gradual evolution while genomic compartmentalization, as manifested in the number of microchromosomes and macrochromosomes, appears to have undergone early rapid change. At the sequence level, the third genomic tier, we find that exon size in Alligator is distributed in a pattern matching that of exons in Gallus (chicken), especially in the 101—200 bp size class. A small spike in the fraction of exons in the 301 bp—1 kb size class is also observed for Alligator, but more so for Sphenodon. For introns, we find that members of Reptilia have a larger fraction of introns within the 101 bp–2 kb size class and a lower fraction of introns within the 5–30 kb size class than do mammals. These findings suggest that the mode of reptilian genome evolution varies across three hierarchical levels of the genome, a pattern consistent with a mosaic model of genomic evolution. PMID:21669810

Dust control effectiveness of drywall sanding tools.

PubMed

Young-Corbett, Deborah E; Nussbaum, Maury A

2009-07-01

In this laboratory study, four drywall sanding tools were evaluated in terms of dust generation rates in the respirable and thoracic size classes. In a repeated measures study design, 16 participants performed simulated drywall finishing tasks with each of four tools: (1) ventilated sander, (2) pole sander, (3) block sander, and (4) wet sponge. Dependent variables of interest were thoracic and respirable breathing zone dust concentrations. Analysis by Friedman's Test revealed that the ventilated drywall sanding tool produced significantly less dust, of both size classes, than did the other three tools. The pole and wet sanders produced significantly less dust of both size classes than did the block sander. The block sander, the most commonly used tool in drywall finishing operations, produced significantly more dust of both size classes than did the other three tools. When compared with the block sander, the other tools offer substantial dust reduction. The ventilated tool reduced respirable concentrations by 88% and thoracic concentrations by 85%. The pole sander reduced respirable concentrations by 58% and thoracic by 50%. The wet sander produced reductions of 60% and 47% in the respirable and thoracic classes, respectively. Wet sponge sanders and pole sanders are effective at reducing breathing-zone dust concentrations; however, based on its superior dust control effectiveness, the ventilated sander is the recommended tool for drywall finishing operations.

Scaling of prosocial behavior in cities

NASA Astrophysics Data System (ADS)

Arbesman, Samuel; Christakis, Nicholas A.

2011-06-01

Previous research has examined how various behaviors scale in cities in relation to their population sizes. Behavior related to innovation and productivity has been found to increase per capita as the size of the city increases, a phenomenon known as superlinear scaling. Criminal behavior has also been found to scale superlinearly. Here we examine a variety of prosocial behaviors (e.g., voting and organ donation), which also would be presumed to be categorized into a single class of scaling with population. We find that, unlike productivity and innovation, prosocial behaviors do not scale in a unified manner. We argue how this might be due to the nature of interactions that are distinct for different prosocial behaviors.

Impact of telecommunication technologies on the middle class formation

NASA Astrophysics Data System (ADS)

Khusnullova, A.; Absalyamova, S.; Sakhapov, R.; Mukhametgalieva, Ch

2017-12-01

The article is devoted to the study of the impact of the information economy on the formation of the middle class. The paper identifies factors contributing to the increase in the share of the middle class in the transition to the information economy. The positive synergetic influence of telecommunication technologies on the formation of the middle class is considered through a possibility of using virtual spaces for labor and educational activities, a possibility of obtaining high returns in the form of dividends on intellectual capital, a qualitative change in the structure of needs, an access to new types of information services, etc. Authors develop a complex model of research of the middle class in the information economy, differing from those available using an expanded list of criteria. In addition to such widely used criteria as income level, level of education and self-identification, the criterion "degree of involvement in the information society" was introduced. The study substantiates that the transition to the information economy made an access to information and communication technologies one of the most significant criteria for social differentiation of society. On the basis of the model, an econometric estimate of the middle class has been carried out, which makes it possible to reveal the share of the middle class in modern society, dynamics of its development, as well as multicollinearity between spending on education, the Gini coefficient, access to information and telecommunication technologies and the size of the middle class.

49 CFR 172.446 - CLASS 9 label.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the six white spaces between them. The lower half of the label must be white with the class number “9... 49 Transportation 2 2010-10-01 2010-10-01 false CLASS 9 label. 172.446 Section 172.446... SECURITY PLANS Labeling § 172.446 CLASS 9 label. (a) Except for size and color, the “CLASS 9...

Arabidopsis Class I and Class II TCP Transcription Factors Regulate Jasmonic Acid Metabolism and Leaf Development Antagonistically1[C][W

PubMed Central

Danisman, Selahattin; van der Wal, Froukje; Dhondt, Stijn; Waites, Richard; de Folter, Stefan; Bimbo, Andrea; van Dijk, Aalt DJ; Muino, Jose M.; Cutri, Lucas; Dornelas, Marcelo C.; Angenent, Gerco C.; Immink, Richard G.H.

2012-01-01

TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR1 (TCP) transcription factors control developmental processes in plants. The 24 TCP transcription factors encoded in the Arabidopsis (Arabidopsis thaliana) genome are divided into two classes, class I and class II TCPs, which are proposed to act antagonistically. We performed a detailed phenotypic analysis of the class I tcp20 mutant, showing an increase in leaf pavement cell sizes in 10-d-old seedlings. Subsequently, a glucocorticoid receptor induction assay was performed, aiming to identify potential target genes of the TCP20 protein during leaf development. The LIPOXYGENASE2 (LOX2) and class I TCP9 genes were identified as TCP20 targets, and binding of TCP20 to their regulatory sequences could be confirmed by chromatin immunoprecipitation analyses. LOX2 encodes for a jasmonate biosynthesis gene, which is also targeted by class II TCP proteins that are under the control of the microRNA JAGGED AND WAVY (JAW), although in an antagonistic manner. Mutation of TCP9, the second identified TCP20 target, resulted in increased pavement cell sizes during early leaf developmental stages. Analysis of senescence in the single tcp9 and tcp20 mutants and the tcp9tcp20 double mutants showed an earlier onset of this process in comparison with wild-type control plants in the double mutant only. Both the cell size and senescence phenotypes are opposite to the known class II TCP mutant phenotype in JAW plants. Altogether, these results point to an antagonistic function of class I and class II TCP proteins in the control of leaf development via the jasmonate signaling pathway. PMID:22718775

Active learning increases student performance in science, engineering, and mathematics.

PubMed

Freeman, Scott; Eddy, Sarah L; McDonough, Miles; Smith, Michelle K; Okoroafor, Nnadozie; Jordt, Hannah; Wenderoth, Mary Pat

2014-06-10

To test the hypothesis that lecturing maximizes learning and course performance, we metaanalyzed 225 studies that reported data on examination scores or failure rates when comparing student performance in undergraduate science, technology, engineering, and mathematics (STEM) courses under traditional lecturing versus active learning. The effect sizes indicate that on average, student performance on examinations and concept inventories increased by 0.47 SDs under active learning (n = 158 studies), and that the odds ratio for failing was 1.95 under traditional lecturing (n = 67 studies). These results indicate that average examination scores improved by about 6% in active learning sections, and that students in classes with traditional lecturing were 1.5 times more likely to fail than were students in classes with active learning. Heterogeneity analyses indicated that both results hold across the STEM disciplines, that active learning increases scores on concept inventories more than on course examinations, and that active learning appears effective across all class sizes--although the greatest effects are in small (n ≤ 50) classes. Trim and fill analyses and fail-safe n calculations suggest that the results are not due to publication bias. The results also appear robust to variation in the methodological rigor of the included studies, based on the quality of controls over student quality and instructor identity. This is the largest and most comprehensive metaanalysis of undergraduate STEM education published to date. The results raise questions about the continued use of traditional lecturing as a control in research studies, and support active learning as the preferred, empirically validated teaching practice in regular classrooms.

Tailored Training in Vehicle Maintenance Courses

DTIC Science & Technology

2014-07-01

The use of the MCT was limited to the 91M test class during this research effort. There were no other limitations imposed by unit leaders on the MCT’s... one group size to another. Since previous discussions with unit training managers indicated about 80% of all training was designed to be executed in... designated small training groups of four to five Soldiers, it was decided that individual observers would be assigned to collect data on only one of

A Note on Cluster Effects in Latent Class Analysis

ERIC Educational Resources Information Center

Kaplan, David; Keller, Bryan

2011-01-01

This article examines the effects of clustering in latent class analysis. A comprehensive simulation study is conducted, which begins by specifying a true multilevel latent class model with varying within- and between-cluster sample sizes, varying latent class proportions, and varying intraclass correlations. These models are then estimated under…

Speech Music Discrimination Using Class-Specific Features

DTIC Science & Technology

2004-08-01

Speech Music Discrimination Using Class-Specific Features Thomas Beierholm...between speech and music . Feature extraction is class-specific and can therefore be tailored to each class meaning that segment size, model orders...interest. Some of the applications of audio signal classification are speech/ music classification [1], acoustical environmental classification [2][3

Statistical Analyses of Femur Parameters for Designing Anatomical Plates.

PubMed

Wang, Lin; He, Kunjin; Chen, Zhengming

2016-01-01

Femur parameters are key prerequisites for scientifically designing anatomical plates. Meanwhile, individual differences in femurs present a challenge to design well-fitting anatomical plates. Therefore, to design anatomical plates more scientifically, analyses of femur parameters with statistical methods were performed in this study. The specific steps were as follows. First, taking eight anatomical femur parameters as variables, 100 femur samples were classified into three classes with factor analysis and Q-type cluster analysis. Second, based on the mean parameter values of the three classes of femurs, three sizes of average anatomical plates corresponding to the three classes of femurs were designed. Finally, based on Bayes discriminant analysis, a new femur could be assigned to the proper class. Thereafter, the average anatomical plate suitable for that new femur was selected from the three available sizes of plates. Experimental results showed that the classification of femurs was quite reasonable based on the anatomical aspects of the femurs. For instance, three sizes of condylar buttress plates were designed. Meanwhile, 20 new femurs are judged to which classes the femurs belong. Thereafter, suitable condylar buttress plates were determined and selected.

Energy Current Cumulants in One-Dimensional Systems in Equilibrium

NASA Astrophysics Data System (ADS)

Dhar, Abhishek; Saito, Keiji; Roy, Anjan

2018-06-01

A recent theory based on fluctuating hydrodynamics predicts that one-dimensional interacting systems with particle, momentum, and energy conservation exhibit anomalous transport that falls into two main universality classes. The classification is based on behavior of equilibrium dynamical correlations of the conserved quantities. One class is characterized by sound modes with Kardar-Parisi-Zhang scaling, while the second class has diffusive sound modes. The heat mode follows Lévy statistics, with different exponents for the two classes. Here we consider heat current fluctuations in two specific systems, which are expected to be in the above two universality classes, namely, a hard particle gas with Hamiltonian dynamics and a harmonic chain with momentum conserving stochastic dynamics. Numerical simulations show completely different system-size dependence of current cumulants in these two systems. We explain this numerical observation using a phenomenological model of Lévy walkers with inputs from fluctuating hydrodynamics. This consistently explains the system-size dependence of heat current fluctuations. For the latter system, we derive the cumulant-generating function from a more microscopic theory, which also gives the same system-size dependence of cumulants.

Validation of a side-scan sonar method for quantifying walleye spawning habitat availability in the littoral zone of northern Wisconsin Lakes

USGS Publications Warehouse

Richter, Jacob T.; Sloss, Brian L.; Isermann, Daniel A.

2016-01-01

Previous research has generally ignored the potential effects of spawning habitat availability and quality on recruitment of Walleye Sander vitreus, largely because information on spawning habitat is lacking for many lakes. Furthermore, traditional transect-based methods used to describe habitat are time and labor intensive. Our objectives were to determine if side-scan sonar could be used to accurately classify Walleye spawning habitat in the nearshore littoral zone and provide lakewide estimates of spawning habitat availability similar to estimates obtained from a transect–quadrat-based method. Based on assessments completed on 16 northern Wisconsin lakes, interpretation of side-scan sonar images resulted in correct identification of substrate size-class for 93% (177 of 191) of selected locations and all incorrect classifications were within ± 1 class of the correct substrate size-class. Gravel, cobble, and rubble substrates were incorrectly identified from side-scan images in only two instances (1% misclassification), suggesting that side-scan sonar can be used to accurately identify preferred Walleye spawning substrates. Additionally, we detected no significant differences in estimates of lakewide littoral zone substrate compositions estimated using side-scan sonar and a traditional transect–quadrat-based method. Our results indicate that side-scan sonar offers a practical, accurate, and efficient technique for assessing substrate composition and quantifying potential Walleye spawning habitat in the nearshore littoral zone of north temperate lakes.

Accuracy assessment of percent canopy cover, cover type, and size class

Treesearch

H. T. Schreuder; S. Bain; R. C. Czaplewski

2003-01-01

Truth for vegetation cover percent and type is obtained from very large-scale photography (VLSP), stand structure as measured by size classes, and vegetation types from a combination of VLSP and ground sampling. We recommend using the Kappa statistic with bootstrap confidence intervals for overall accuracy, and similarly bootstrap confidence intervals for percent...

Principals as Middle Managers: School Leadership during the Implementation of Primary Class Size Reduction Policy in Ontario

ERIC Educational Resources Information Center

Flessa, Joseph J.

2012-01-01

Previous work on policy implementation has often suggested that schools leave their "thumbprints" on policies received from above. During the implementation of Primary Class Size Reduction (PCS) Initiative in Ontario, Canada, however, school principals spoke with remarkable uniformity about the ways PCS affected their work. This article…

District Resource Capacity and the Effects of Educational Policy: The Case of Primary Class Size Reduction in Ontario

ERIC Educational Resources Information Center

Mascall, Blair; Leung, Joannie

2012-01-01

In a study of Ontario, Canada's province-wide Primary Class Size Reduction (PCS) Initiative, school districts' ability to direct and support schools was related to their experience with planning and monitoring, interest in innovation, and its human and fiscal resource base. Districts with greater "resource capacity" were able to…

The Causal Effect of Class Size on Academic Achievement: Multivariate Instrumental Variable Estimators with Data Missing at Random

ERIC Educational Resources Information Center

Shin, Yongyun; Raudenbush, Stephen W.

2011-01-01

This article addresses three questions: Does reduced class size cause higher academic achievement in reading, mathematics, listening, and word recognition skills? If it does, how large are these effects? Does the magnitude of such effects vary significantly across schools? The authors analyze data from Tennessee's Student/Teacher Achievement Ratio…

Relationship between Class Size and Students' Opportunity to Learn Writing in Middle School

ERIC Educational Resources Information Center

Tienken, Christopher H.; Achilles, Charles M.

2009-01-01

Class-size reduction (CSR) initiatives have demonstrated positive short- and long-term effects in elementary grades. Less is known about CSR influence on achievement in middle grades. Thus, we conducted a non-experimental, longitudinal, explanatory study of CSR influence on writing achievement of 3 independent cohorts of students (n = 123) in…

An Evaluation of the Federal Class-Size Reduction Program in Wake County, North Carolina--1999-2000.

ERIC Educational Resources Information Center

Scudder, David F.

An empirical evaluation of the federal class-size reduction (CSR) program in Wake County, North Carolina, during the 1999-2000 school year is presented. The qualitative process evaluation showed implementation issues involving the mechanics and the meaning of CSR. Often, schools did not understand where CSR occurred because of changing enrollment…

Learning Approaches and Lecture Attendance of Medical Students

ERIC Educational Resources Information Center

Bates, Madeleine; Curtis, Sally; Dismore, Harriet

2018-01-01

There are arguably many factors that affect the way a student learns. A recent report by the Higher Education Policy Institute (HEPI) and the Higher Education Academy (HEA) on student academic experience in the UK states that class size is an important factor in the quality of the student experience and that smaller class sizes provide greater…

A Plan for the Evaluation of California's Class Size Reduction Initiative.

ERIC Educational Resources Information Center

Kirst, Michael; Bomstedt, George; Stecher, Brian

In July 1996, California began its Class Size Reduction (CSR) Initiative. To gauge the effectiveness of this initiative, an analysis of its objectives and an overview of proposed strategies for evaluating CSR are presented here. An outline of the major challenges that stand between CSR and its mission are provided. These include logistical…

Ontario's Primary Class Size Reduction Initiative: Report on Early Implementation

ERIC Educational Resources Information Center

Bascia, Nina

2010-01-01

Reduction in the size of classes from Kindergarten to Grade 3 was a major Liberal Party campaign promise in Ontario's 2003 provincial election. It was intended to demonstrate a new government's commitment to improving public education. By the 2008-09 school year, the provincial government's goals had been achieved: over 90% of all primary classes…

You Just Feed Them with a Long-Handled Spoon: Families Evaluate Their Experiences in a Class Size Reduction Reform

ERIC Educational Resources Information Center

Graue, M. Elizabeth; Oen, Denise

2009-01-01

Emerging from an evaluation of Wisconsin's Student Achievement Guarantee in Education program (SAGE), a multidimensional program popularly known for its class size reduction component, this article examines SAGE's "lighted schoolhouse" initiative aimed to strengthen links between home and school. Drawing on family focus groups held at…

Study of Cost of Distance Education Institutes with Different Size Classes in India.

ERIC Educational Resources Information Center

Datt, Ruddar

A study of the cost of distance education institutes in India with different size classes involved nine institutions. The sample included 47 percent of total enrollment in distance education institutions in India. The study was restricted to recurring costs and examined the shares of different components of costs and the sources of funding. It…

Using Flexible Busing to Meet Average Class Size Targets

ERIC Educational Resources Information Center

Felt, Andrew J.; Koelemay, Ryan; Richter, Alexander

2008-01-01

This article describes a method of flexible redistricting for K-12 public school districts that allows students from the same geographical region to be bused to different schools, with the goal of meeting average class size (ACS) target ranges. Results of a case study on a geographically large school district comparing this method to a traditional…

Sound Levels in East Texas Schools.

ERIC Educational Resources Information Center

Turner, Aaron Lynn

A survey of sound levels was taken in several Texas schools to determine the amount of noise and sound present by size of class, type of activity, location of building, and the presence of air conditioning and large amounts of glass. The data indicate that class size and relative amounts of glass have no significant bearing on the production of…

The Nevada Class Size Reduction Evaluation Study, 1995.

ERIC Educational Resources Information Center

Nevada State Dept. of Education, Carson City.

A primary purpose for reducing the student-teacher ratio in the early grades is to make students more successful in their later years. This document contains two separate, but interrelated reports that examined two aspects of the 1989 Class Size Reduction (CSR) Act in Nevada. The Act called for a reduction in student-teacher ratios for selected…

40 CFR 113.4 - Size classes and associated liability limits for fixed onshore oil storage facilities, 1,000...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 23 2012-07-01 2012-07-01 false Size classes and associated liability limits for fixed onshore oil storage facilities, 1,000 barrels or less capacity. 113.4 Section 113.4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS LIABILITY LIMITS FOR...

40 CFR 113.4 - Size classes and associated liability limits for fixed onshore oil storage facilities, 1,000...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 22 2014-07-01 2013-07-01 true Size classes and associated liability limits for fixed onshore oil storage facilities, 1,000 barrels or less capacity. 113.4 Section 113.4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS LIABILITY LIMITS FOR...

An Examination of Class Size Reduction on Teaching and Learning Processes: A Theoretical Perspective

ERIC Educational Resources Information Center

Harfitt, Gary James; Tsui, Amy B. M.

2015-01-01

The question of how class size impacts on student learning has been debated for some time, not least because it has substantial financial implications for educational policy. The strength of this debate notwithstanding, results from numerous international studies have been inconclusive. The study from which this paper stems sought to conceptualise…

Examine Middle School Students' Constructivist Environment Perceptions in Turkey: School Location and Class Size

ERIC Educational Resources Information Center

Yigit, Nevzat; Alpaslan, Muhammet Mustafa; Cinemre, Yasin; Balcin, Bilal

2017-01-01

This study aims to examine the middle school students' perceptions of the classroom learning environment in the science course in Turkey in terms of school location and class size. In the study the Assessing of Constructivist Learning Environment (ACLE) questionnaire was utilized to map students' perceptions of the classroom learning environment.…

Working Conditions and Workplace Barriers to Vocal Health in Primary School Teachers.

PubMed

Munier, Caitriona; Farrell, Rory

2016-01-01

The purpose of this study was to identify the working conditions and workplace barriers to vocal health in primary school teachers. The relationship between working conditions and voice is analyzed. This is a survey study in 42 randomized schools from a restricted geographical area. An 85-item questionnaire was administered to 550 primary school teachers in 42 schools in Dublin. It was designed to obtain information on demographics, vocal use patterns, vocal health, work organization, working conditions, and teacher's perceptions of the conditions in teaching that might cause a voice problem. The relationship between voice and overstretched work demands, and voice and class size, was examined. A chi-squared test was run to test the null hypothesis that the variables overstretched work demands and voice and class size and voice are independent. Subjects were given the opportunity to give their opinion on their working conditions and on the availability of advice and support within the workplace. A final question sought their opinion on what should be included in a voice care program. A 55% response rate was obtained (n = 304). It was found with 96.52% confidence that the variables overstretched work demands and voice are related. Likewise, it was found that the variables class size and voice are related with 99.97% confidence. There are workplace barriers to vocal health. The working conditions of primary school teachers need to be fully adapted to promote vocal health. Changes by education and health policy makers are needed to achieve this goal. There is a need for future research which focuses on the working conditions of teachers. Copyright © 2016. Published by Elsevier Inc.

SU-C-304-07: Are Small Field Detector Correction Factors Strongly Dependent On Machine-Specific Characteristics?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mathew, D; Tanny, S; Parsai, E

2015-06-15

Purpose: The current small field dosimetry formalism utilizes quality correction factors to compensate for the difference in detector response relative to dose deposited in water. The correction factors are defined on a machine-specific basis for each beam quality and detector combination. Some research has suggested that the correction factors may only be weakly dependent on machine-to-machine variations, allowing for determinations of class-specific correction factors for various accelerator models. This research examines the differences in small field correction factors for three detectors across two Varian Truebeam accelerators to determine the correction factor dependence on machine-specific characteristics. Methods: Output factors were measuredmore » on two Varian Truebeam accelerators for equivalently tuned 6 MV and 6 FFF beams. Measurements were obtained using a commercial plastic scintillation detector (PSD), two ion chambers, and a diode detector. Measurements were made at a depth of 10 cm with an SSD of 100 cm for jaw-defined field sizes ranging from 3×3 cm{sup 2} to 0.6×0.6 cm{sup 2}, normalized to values at 5×5cm{sup 2}. Correction factors for each field on each machine were calculated as the ratio of the detector response to the PSD response. Percent change of correction factors for the chambers are presented relative to the primary machine. Results: The Exradin A26 demonstrates a difference of 9% for 6×6mm{sup 2} fields in both the 6FFF and 6MV beams. The A16 chamber demonstrates a 5%, and 3% difference in 6FFF and 6MV fields at the same field size respectively. The Edge diode exhibits less than 1.5% difference across both evaluated energies. Field sizes larger than 1.4×1.4cm2 demonstrated less than 1% difference for all detectors. Conclusion: Preliminary results suggest that class-specific correction may not be appropriate for micro-ionization chamber. For diode systems, the correction factor was substantially similar and may be useful for class-specific reference conditions.« less

Low cost forged Y-pattern valves control hot corrosive/erosive gases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaines, A.

The Morgantown Energy Technology Center in Morgantown, West Virginia is a research facility of the US Department of Energy (DOE) that does research on fossil fuels utilization and conversion to provide improved and environmentally acceptable energy sources. One area of investigation in the Morgantown facility is the use of gaseous fuels derived from coal from fluidized-bed and fixed-bed gasification technologies. The corrosive and slightly erosive gases and vapors at about 1000F and from 100 to 300 psi are treated in an experimental desulfurization unit to produce fuel gas with greatly enhanced environmental characteristics. The valves in use were constructed ofmore » Type 347 stainless steel, a stabilized version of 316 SS, and cost about $6000 for the 2'' size and about $4000 for the 1'' size. Despite the high cost, the valve sometimes became difficult or impossible to operate due to metal failures. The Technology Center had a number of new Class 1500 Y-pattern (angle-style) globe valves in inventory. The control valve body and bonnet are forged chrome moly steel (ASTM-H182-F22), the stem assembly is a 13% chrome alloy with an erosion resistant hard faced disc, and the seat ring is a cobalt-base alloy fused in place as an integral part of the body. Stem packing as an either wire inserted molded asbestos or Grafoil flexible graphite. The Y-pattern globe valves in 1 and 2'' sizes, which were judged potentially suitable and on hand, were installed in the experimental desulfization unit as well as in the connecting hot gas piping system to a new coal gasification process. The Class 1500 Y-pattern valves have provided reliable control of the hot corrosive and erosive gas streams with very little maintenance.« less

Obesity and vehicle type as risk factors for injury caused by motor vehicle collision.

PubMed

Donnelly, John P; Griffin, Russell Lee; Sathiakumar, Nalini; McGwin, Gerald

2014-04-01

This study sought to describe variations in the risk of motor vehicle collision (MVC) injury and death by occupant body mass index (BMI) class and vehicle type. We hypothesized that the relationship between BMI and the risk of MVC injury or mortality would be modified by vehicle type. This is a retrospective cohort study of occupants involved in MVCs using data from the Crash Injury Research and Engineering Network and the National Automotive Sampling System Crashworthiness Data System. Occupants were grouped based on vehicle body style (passenger car, sport utility vehicle, or light truck) and vehicle size (compact or normal, corresponding to below- or above-average curb weight). The relationship between occupant BMI class (underweight, normal weight, overweight, or obese) and risk of injury or mortality was examined for each vehicle type. Odds ratios (ORs) adjusted for various occupant and collision characteristics were estimated. Of an estimated 44 million occupants of MVCs sampled from 2000 to 2009, 37.1% sustained an injury. We limited our analysis to injuries achieving an Abbreviated Injury Scale (AIS) score of 2 or more severe, totaling 17 million injuries. Occupants differed substantially in terms of demographic and collision characteristics. After adjustment for confounding factors, we found that obesity was a risk factor for mortality caused by MVC (OR, 1.6; 95% confidence interval [CI], 1.2-2.0). When stratified by vehicle type, we found that obesity was a risk factor for mortality in larger vehicles, including any-sized light trucks (OR, 2.1; 95% CI, 1.3-3.5), normal-sized passenger cars (OR, 1.6; 95% CI, 1.1-2.3), and normal-sized sports utility vehicles or vans (OR, 2.0; 95% CI, 1.0-3.8). Being overweight was a risk factor in any-sized light trucks (OR, 1.5; 95% CI, 1.1-2.1). We identified a significant interaction between occupant BMI class and vehicle type in terms of MVC-related mortality risk. Both factors should be taken into account when considering occupant safety, and additional study is needed to determine underlying causes of the observed relationships. Epidemiologic study, level III.

Origin of Outer Solar System

NASA Technical Reports Server (NTRS)

Holman, Matthew J.; Lindstrom, David (Technical Monitor)

2005-01-01

Our ongoing research program combines extensive deep and wide-field observations using a variety of observational platforms with numerical studies of the dynamics of small bodies in the outer solar system in order to advance the main scientific goals of the community studying the Kuiper belt and the outer solar system. These include: (1) determining the relative populations of the known classes of KBOs as well as other possible classes; ( 2 ) determining the size distributions or luminosity function of the individual populations or the Kuiper belt as a whole; (3) determining the inclinations distributions of these populations; (4) establishing the radial extent of the Kuiper belt; ( 5 ) measuring and relating the physical properties of different types of KBOs to those of other solar system bodies; and, (6) completing our systematic inventory of the satellites of the outer planets.

Review of "The Impact of a Universal Class-Size Reduction Policy: Evidence from Florida's Statewide Mandate"

ERIC Educational Resources Information Center

Finn, Jeremy D.

2010-01-01

In 2002, voters in Florida approved a constitutional amendment limiting class sizes in public schools to 18 students in the elementary grades, 22 students in middle grades, and 25 in high school grades. Analyzing statewide achievement data for school districts from 2004-2006 and for schools in 2007, this study purports to find that "mandated…

Factors in the Determination of Cost Effective Class Sizes. Report No. 009-79.

ERIC Educational Resources Information Center

Woods, Nancy A.

A system to determine cost effectiveness of class size should be based on both budgeted and actual expenditures and credit hours at the individual course section level. These two factors, in combination, are often expressed as cost per credit hour, and this statistic forms the primary means of evaluating planned "inputs" against actual "outputs."…

Understanding the Effect of Response Rate and Class Size Interaction on Students Evaluation of Teaching in a Higher Education

ERIC Educational Resources Information Center

Al Kuwaiti, Ahmed; AlQuraan, Mahmoud; Subbarayalu, Arun Vijay

2016-01-01

Objective: This study aims to investigate the interaction between response rate and class size and its effects on students' evaluation of instructors and the courses offered at a higher education Institution in Saudi Arabia. Study Design: A retrospective study design was chosen. Methods: One thousand four hundred and forty four different courses…

So How Big Is Big? Investigating the Impact of Class Size on Ratings in Student Evaluation

ERIC Educational Resources Information Center

Gannaway, Deanne; Green, Teegan; Mertova, Patricie

2018-01-01

Australian universities have a long history of use of student satisfaction surveys. Their use has expanded and purpose changed over time. The surveys are often viewed as distorted by external influences such as discipline context, class size and year level of participants. This paper reports on the results of a large-scale investigation…

Scaling Up: Faculty Workload, Class Size, and Student Satisfaction in a Distance Learning Course on Geographic Information Science.

ERIC Educational Resources Information Center

Dibiase, David; Rademacher, Henry J.

2005-01-01

This article explores issues of scalability and sustainability in distance learning. The authors kept detailed records of time they spent teaching a course in geographic information science via the World Wide Web over a six-month period, during which class sizes averaged 49 students. The authors also surveyed students' satisfaction with the…

The Impact of California's Class Size Reduction Initiative on Student Achievement: Detailed Findings from Eight School Districts.

ERIC Educational Resources Information Center

Mitchell, Douglas E.; Mitchell, Ross E.

This report presents a comprehensive preliminary analysis of how California's Class Size Reduction (CSR) initiative has impacted student achievement during the first 2 years of implementation. The analysis is based on complete student, classroom, and teacher records from 26,126 students in 1,174 classrooms from 83 schools in 8 Southern California…

Suitability of river delta sediment as proppant, Missouri and Niobrara Rivers, Nebraska and South Dakota, 2015

USGS Publications Warehouse

Zelt, Ronald B.; Hobza, Christopher M.; Burton, Bethany L.; Schaepe, Nathaniel J.; Piatak, Nadine

2017-11-16

Sediment management is a challenge faced by reservoir managers who have several potential options, including dredging, for mitigation of storage capacity lost to sedimentation. As sediment is removed from reservoir storage, potential use of the sediment for socioeconomic or ecological benefit could potentially defray some costs of its removal. Rivers that transport a sandy sediment load will deposit the sand load along a reservoir-headwaters reach where the current of the river slackens progressively as its bed approaches and then descends below the reservoir water level. Given a rare combination of factors, a reservoir deposit of alluvial sand has potential to be suitable for use as proppant for hydraulic fracturing in unconventional oil and gas development. In 2015, the U.S. Geological Survey began a program of researching potential sources of proppant sand from reservoirs, with an initial focus on the Missouri River subbasins that receive sand loads from the Nebraska Sand Hills. This report documents the methods and results of assessments of the suitability of river delta sediment as proppant for a pilot study area in the delta headwaters of Lewis and Clark Lake, Nebraska and South Dakota. Results from surface-geophysical surveys of electrical resistivity guided borings to collect 3.7-meter long cores at 25 sites on delta sandbars using the direct-push method to recover duplicate, 3.8-centimeter-diameter cores in April 2015. In addition, the U.S. Geological Survey collected samples of upstream sand sources in the lower Niobrara River valley.At the laboratory, samples were dried, weighed, washed, dried, and weighed again. Exploratory analysis of natural sand for determining its suitability as a proppant involved application of a modified subset of the standard protocols known as American Petroleum Institute (API) Recommended Practice (RP) 19C. The RP19C methods were not intended for exploration-stage evaluation of raw materials. Results for the washed samples are not directly applicable to evaluations of suitability for use as fracture sand because, except for particle-size distribution, the API-recommended practices for assessing proppant properties (sphericity, roundness, bulk density, and crush resistance) require testing of specific proppant size classes. An optical imaging particle-size analyzer was used to make measurements of particle-size distribution and particle shape. Measured samples were sieved to separate the dominant-size fraction, and the separated subsample was further tested for roundness, sphericity, bulk density, and crush resistance.For the bulk washed samples collected from the Missouri River delta, the geometric mean size averaged 0.27 millimeters (mm), 80 percent of the samples were predominantly sand in the API 40/70 size class, and 17 percent were predominantly sand in the API 70/140 size class. Distributions of geometric mean size among the four sandbar complexes were similar, but samples collected from sandbar complex B were slightly coarser sand than those from the other three complexes. The average geometric mean sizes among the four sandbar complexes ranged only from 0.26 to 0.30 mm. For 22 main-stem sampling locations along the lower Niobrara River, geometric mean size averaged 0.26 mm, an average of 61 percent was sand in the API 40/70 size class, and 28 percent was sand in the API 70/140 size class. Average composition for lower Niobrara River samples was 48 percent medium sand, 37 percent fine sand, and about 7 percent each very fine sand and coarse sand fractions. On average, samples were moderately well sorted.Particle shape and strength were assessed for the dominant-size class of each sample. For proppant strength, crush resistance was tested at a predetermined level of stress (34.5 megapascals [MPa], or 5,000 pounds-force per square inch). To meet the API minimum requirement for proppant, after the crush test not more than 10 percent of the tested sample should be finer than the precrush dominant-size class. For particle shape, all samples surpassed the recommended minimum criteria for sphericity and roundness, with most samples being well-rounded. For proppant strength, of 57 crush-resistance tested Missouri River delta samples of 40/70-sized sand, 23 (40 percent) were interpreted as meeting the minimum criterion at 34.5 MPa, or 5,000 pounds-force per square inch. Of 12 tested samples of 70/140-sized sand, 9 (75 percent) of the Missouri River delta samples had less than 10 percent fines by volume following crush testing, achieving the minimum criterion at 34.5 MPa. Crush resistance for delta samples was strongest at sandbar complex A, where 67 percent of tested samples met the 10-percent fines criterion at the 34.5-MPa threshold. This frequency was higher than was indicated by samples from sandbar complexes B, C, and D that had rates of 50, 46, and 42 percent, respectively. The group of sandbar complex A samples also contained the largest percentages of samples dominated by the API 70/140 size class, which overall had a higher percentage of samples meeting the minimum criterion compared to samples dominated by coarser size classes; however, samples from sandbar complex A that had the API 40/70 size class tested also had a higher rate for meeting the minimum criterion (57 percent) than did samples from sandbar complexes B, C, and D (50, 43, and 40 percent, respectively). For samples collected along the lower Niobrara River, of the 25 tested samples of 40/70-sized sand, 9 samples passed the API minimum criterion at 34.5 MPa, but only 3 samples passed the more-stringent criterion of 8 percent postcrush fines. All four tested samples of 70/140 sand passed the minimum criterion at 34.5 MPa, with postcrush fines percentage of at most 4.1 percent.For two reaches of the lower Niobrara River, where hydraulic sorting was energized artificially by the hydraulic head drop at and immediately downstream from Spencer Dam, suitability of channel deposits for potential use as fracture sand was confirmed by test results. All reach A washed samples were well-rounded and had sphericity scores above 0.65, and samples for 80 percent of sampled locations met the crush-resistance criterion at the 34.5-MPa stress level. A conservative lower-bound estimate of sand volume in the reach A deposits was about 86,000 cubic meters. All reach B samples were well-rounded but sphericity averaged 0.63, a little less than the average for upstream reaches A and SP. All four samples tested passed the crush-resistance test at 34.5 MPa. Of three reach B sandbars, two had no more than 3 percent fines after the crush test, surpassing more stringent criteria for crush resistance that accept a maximum of 6 percent fines following the crush test for the API 70/140 size class.Relative to the crush-resistance test results for the API 40/70 size fraction of two samples of mine output from Loup River settling-basin dredge spoils near Genoa, Nebr., four of five reach A sample locations compared favorably. The four samples had increases in fines composition of 1.6–5.9 percentage points, whereas fines in the two mine-output samples increased by an average 6.8 percentage points.

EP of a Different Class: The Challenges of Testing for MW Missions

DTIC Science & Technology

2012-07-20

that the pumping capacity of the Large Vacuum Test Facility (LVTF) at PEPL (Figure 3) at 520,000 l/s on air makes it most suitable for initial checkout...evaluation of the thruster. NASA Glenn Research Center’s Vacuum Facility 5 (VF5) (Figure 4), with its increased pumping speed of 3,500,000 l/s on air...reader to Dr. Dan Goebel’s IEPC 2011 paper.41 IV. Facility Selection and Preparation Facility Size and Pumping High T/P thruster testing

Back to the Future: Building resilience in Colorado Front Range forests using research findings and a new guide for restoration of ponderosa and dry-mixed conifer landscapes

Treesearch

Sue Miller; Rob Addington; Greg Aplet; Mike Battaglia; Tony Cheng; Jonas Feinstein; Jeff Underhill

2018-01-01

Historically, the ponderosa and dry mixed-conifer forests of the Colorado Front Range were more open and grassy, and trees of all size classes were found in a grouped arrangement with sizable openings between the clumps. As a legacy of fire suppression, today’s forests are denser, with smaller trees. Proactive restoration of this forest type will help to reduce fuel...

Estimating accuracy of land-cover composition from two-stage cluster sampling

USGS Publications Warehouse

Stehman, S.V.; Wickham, J.D.; Fattorini, L.; Wade, T.D.; Baffetta, F.; Smith, J.H.

2009-01-01

Land-cover maps are often used to compute land-cover composition (i.e., the proportion or percent of area covered by each class), for each unit in a spatial partition of the region mapped. We derive design-based estimators of mean deviation (MD), mean absolute deviation (MAD), root mean square error (RMSE), and correlation (CORR) to quantify accuracy of land-cover composition for a general two-stage cluster sampling design, and for the special case of simple random sampling without replacement (SRSWOR) at each stage. The bias of the estimators for the two-stage SRSWOR design is evaluated via a simulation study. The estimators of RMSE and CORR have small bias except when sample size is small and the land-cover class is rare. The estimator of MAD is biased for both rare and common land-cover classes except when sample size is large. A general recommendation is that rare land-cover classes require large sample sizes to ensure that the accuracy estimators have small bias. ?? 2009 Elsevier Inc.

Computational techniques for flows with finite-rate condensation

NASA Technical Reports Server (NTRS)

Candler, Graham V.

1993-01-01

A computational method to simulate the inviscid two-dimensional flow of a two-phase fluid was developed. This computational technique treats the gas phase and each of a prescribed number of particle sizes as separate fluids which are allowed to interact with one another. Thus, each particle-size class is allowed to move through the fluid at its own velocity at each point in the flow field. Mass, momentum, and energy are exchanged between each particle class and the gas phase. It is assumed that the particles do not collide with one another, so that there is no inter-particle exchange of momentum and energy. However, the particles are allowed to grow, and therefore, they may change from one size class to another. Appropriate rates of mass, momentum, and energy exchange between the gas and particle phases and between the different particle classes were developed. A numerical method was developed for use with this equation set. Several test cases were computed and show qualitative agreement with previous calculations.

The Influence of pH on Prokaryotic Cell Size and Temperature

NASA Astrophysics Data System (ADS)

Sundararajan, D.; Gutierrez, F.; Heim, N. A.; Payne, J.

2015-12-01

The pH of a habitat is essential to an organism's growth and success in its environment. Although most organisms maintain a neutral internal pH, their environmental pH can vary greatly. However, little research has been done concerning an organism's environmental pH across a wide range of taxa. We studied pH tolerance in prokaryotes and its relationship with biovolume, taxonomic classification, and ideal temperature. We had three hypotheses: pH and temperature are not correlated; pH tolerance is similar within taxonomic groups; and extremophiles have small cell sizes. To test these hypotheses, we used pH, size, and taxonomic data from The Prokaryotes. We found that the mean optimum external pH was neutral for prokaryotes as a whole and when divided by domain, phylum, and class. Using ANOVA to test for pH within and among group variances, we found that variation of pH in domains, phyla, classes, and families was greater than between them. pH and size did not show much of a correlation, except that the largest and smallest sized prokaryotes had nearly neutral pH. This seems significant because extremophiles need to divert more of their energy from growth to maintain a neutral internal pH. Acidophiles showed a larger range of optimum pH values than alkaliphiles. A similar result was seen with the minimum and maximum pH values of acidophiles and alkaliphiles. While acidophiles were spread out and had some alkaline maximum values, alkaliphiles had smaller ranges, and unlike some acidophiles that had pH minimums close to zero, alkaliphile pH maximums did not go beyond a pH of 12. No statistically significant differences were found between sizes of acidophiles and alkaliphiles. However, optimum temperatures of acidophiles and alkaliphiles did have a statistically significant difference. pH and temperature had a negative correlation. Therefore, pH seems to have a correlation with cell size, temperature, and taxonomy to some extent.

No evidence of nonlinear effects of predator density, refuge availability, or body size of prey on prey mortality rates.

PubMed

Simkins, Richard M; Belk, Mark C

2017-08-01

Predator density, refuge availability, and body size of prey can all affect the mortality rate of prey. We assume that more predators will lead to an increase in prey mortality rate, but behavioral interactions between predators and prey, and availability of refuge, may lead to nonlinear effects of increased number of predators on prey mortality rates. We tested for nonlinear effects in prey mortality rates in a mesocosm experiment with different size classes of western mosquitofish ( Gambusia affinis ) as the prey, different numbers of green sunfish ( Lepomis cyanellus ) as the predators, and different levels of refuge. Predator number and size class of prey, but not refuge availability, had significant effects on the mortality rate of prey. Change in mortality rate of prey was linear and equal across the range of predator numbers. Each new predator increased the mortality rate by about 10% overall, and mortality rates were higher for smaller size classes. Predator-prey interactions at the individual level may not scale up to create nonlinearity in prey mortality rates with increasing predator density at the population level.

Signal detection evidence for limited capacity in visual search

PubMed Central

Fencsik, David E.; Flusberg, Stephen J.; Horowitz, Todd S.; Wolfe, Jeremy M.

2014-01-01

The nature of capacity limits (if any) in visual search has been a topic of controversy for decades. In 30 years of work, researchers have attempted to distinguish between two broad classes of visual search models. Attention-limited models have proposed two stages of perceptual processing: an unlimited-capacity preattentive stage, and a limited-capacity selective attention stage. Conversely, noise-limited models have proposed a single, unlimited-capacity perceptual processing stage, with decision processes influenced only by stochastic noise. Here, we use signal detection methods to test a strong prediction of attention-limited models. In standard attention-limited models, performance of some searches (feature searches) should only be limited by a preattentive stage. Other search tasks (e.g., spatial configuration search for a “2” among “5”s) should be additionally limited by an attentional bottleneck. We equated average accuracies for a feature and a spatial configuration search over set sizes of 1–8 for briefly presented stimuli. The strong prediction of attention-limited models is that, given overall equivalence in performance, accuracy should be better on the spatial configuration search than on the feature search for set size 1, and worse for set size 8. We confirm this crossover interaction and show that it is problematic for at least one class of one-stage decision models. PMID:21901574

Disadvantaged Students in the Early Grades: Will Smaller Classes Help Them?

ERIC Educational Resources Information Center

Vaag Iversen, Jon Marius; Bonesrønning, Hans

2013-01-01

This paper uses data from the Norwegian elementary school to test whether students from disadvantaged backgrounds benefit from smaller classes. The data cover one cohort of fourth graders who have been treated in small versus large classes for a period of three years. The Norwegian class size rule of maximum 28 students is used to generate…

78 FR 62785 - Self-Regulatory Organizations; Topaz Exchange, LLC; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-22

... will automatically remove a market maker's quotes in all series of an options class when certain... on a class-by-class basis. These parameters are available for market maker quotes in single options... contracts executed by the market maker in an options class; (2) the percentage of the total size of the...

Intrinsic classes in the Union of European Football Associations soccer team ranking

NASA Astrophysics Data System (ADS)

Ausloos, Marcel

2014-11-01

A strong structural regularity of classes is found in soccer teams ranked by the Union of European Football Associations (UEFA) for the time interval 2009-2014. It concerns 424 to 453 teams according to the 5 competition seasons. The analysis is based on the rank-size theory considerations, the size being the UEFA coefficient at the end of a season. Three classes emerge: (i) the few "top" teams, (ii) 300 teams, (iii) the rest of the involved teams (about 150) in the tail of the distribution. There are marked empirical laws describing each class. A 3-parameter Lavalette function is used to describe the concave curving as the rank increases, and to distinguish the the tail from the central behavior.

Effect of lecture instruction on student performance on qualitative questions

NASA Astrophysics Data System (ADS)

Heron, Paula R. L.

2015-06-01

The impact of lecture instruction on student conceptual understanding in physics has been the subject of research for several decades. Most studies have reported disappointingly small improvements in student performance on conceptual questions despite direct instruction on the relevant topics. These results have spurred a number of attempts to improve learning in physics courses through new curricula and instructional techniques. This paper contributes to the research base through a retrospective analysis of 20 randomly selected qualitative questions on topics in kinematics, dynamics, electrostatics, waves, and physical optics that have been given in introductory calculus-based physics at the University of Washington over a period of 15 years. In some classes, questions were administered after relevant lecture instruction had been completed; in others, it had yet to begin. Simple statistical tests indicate that the average performance of the "after lecture" classes was significantly better than that of the "before lecture" classes for 11 questions, significantly worse for two questions, and indistinguishable for the remaining seven. However, the classes had not been randomly assigned to be tested before or after lecture instruction. Multiple linear regression was therefore conducted with variables (such as class size) that could plausibly lead to systematic differences in performance and thus obscure (or artificially enhance) the effect of lecture instruction. The regression models support the results of the simple tests for all but four questions. In those cases, the effect of lecture instruction was reduced to a nonsignificant level, or increased to a significant, negative level when other variables were considered. Thus the results provide robust evidence that instruction in lecture can increase student ability to give correct answers to conceptual questions but does not necessarily do so; in some cases it can even lead to a decrease.

Teaching (an introduction to!) fractals and rainfall features in kinder garden

NASA Astrophysics Data System (ADS)

Gires, Auguste; Villepoux, Mélanie; Rouellé, Valérie

2014-05-01

Why trying to teach fractals or rainfall drop size distribution to 3 to 5 year old children? Because it can easily be done in a (rather!) fun way, enabling children to grasp some complex notions and more generally get familiarized with science. This paper presents the outputs of a collaboration between a researcher and two kinder garden teachers which resulted in activities dealing with fractals and rainfall that were implemented in their class. Fractals are geometrical objects that exhibit a similar structure at all scales. A classical natural example is a fern leaf around which an activity was developed and implemented with children aged 3-4. The first step consisted in trying to make them feel the fractal nature of the fern leaf, i.e. a whole leaf is made of smaller leafs which are also made of even smaller leafs exhibiting similar shapes. Four activities were specifically designed for this. In the second step the fractal nature of the fern leaf was used to enable the class to draw a large leaf in a collaborative way. More precisely, each child draw a leaf and they were all assembled to draw a greater one. A similar activity but this time with geometrical shapes based on triangles was implemented with kids aged 4-5. The output was a great Sierpinski triangle. Rain drops typically exhibit sizes ranging from 0.2 to 5 mm (in terms of equivolumic diameter), and scientists uses disdrometers to analyse this distribution. An activity that consisted in developing and testing two disdrometers was implemented in a class with children aged 5-6. The disdrometers consisted of a plate with a thin layer of either flour or oil. The features of the two devices were initially compared with the help of artificial drops generated by the children with a pipette. Then the disdrometers were briefly (few seconds) put under the rain. In order to help children notice the wide variety of drop sizes they were asked to draw what they saw. Finally an activity based on times series of rainy and non-rainy days (recorded by the class) whose aim is to the show the fractal nature of rainfall and to introduce the notion of random models will briefly be discussed. Authors acknowledged the North-West Europe Interreg IV RainGain project (raingain.eu) and the Climate KIC Blue Green Dream project (bgd.org.uk) for funding the underlying research associated with these activities.

Teachers and Group Size as Variables in Stimulating Oral Language Development with Grade One Disadvantaged Children. IMRID, Volume III, No. 1.

ERIC Educational Resources Information Center

Dunn, Lloyd M.; And Others

The purpose of this study was to evaluate both the relative effectiveness of different instructional personnel and the effect of differences in group size upon oral language acquisition for educationally disadvantaged first grade children. Involved in the treatment program were 23 classes in eight schools, all serving lower class areas of a…

Estimating live fuels for shrubs and herbs with BIOPAK.

Treesearch

Joseph E. Means; Olga N Krankina; Hao Jiang; Hongyan Li

1996-01-01

This paper describes use of BIOPAK to calculate size classes of live fuels for shrubs and herbs. A library of equations to estimate such fuels in the Pacific Northwest and northern Rocky Mountains is presented and used in an example. These methods can be used in other regions if the user first enters fuel size-class equations for a given region into a new library by...

A Study on the Learning Processes in Discrimination Shift Learning of Children with Mental Retardation: From the Point of Developmental View of "Logical Manipulation by Classification."

ERIC Educational Resources Information Center

Kanno, Atsushi

1989-01-01

The study was designed to investigate the learning processes in discrimination shift learning, in terms of developmental views of "logical manipulation by classification." Tasks comparing sizes of intradimensional value-classes and comparing sizes of interdimensional value-classes were devised in order to measure subjects' levels of…

Assessing Juvenile Salmonid Passage Through Culverts: Field Research in Support of Protocol Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Greg D.; Evans, Nathan R.; Pearson, Walter H.

2001-10-30

The primary goal of our research this spring/ summer was to refine techniques and examine scenarios under which a standardized protocol could be applied to assess juvenile coho salmon (O. kisutch) passage through road culverts. Field evaluations focused on capture-mark- recapture methods that allowed analysis of fish movement patterns, estimates of culvert passability, and potential identification of cues inducing these movements. At this stage, 0+ age coho salmon fry 30 mm to 65 mm long (fork length) were the species and age class of interest. Ultimately, the protocol will provide rapid, statistically rigorous methods for trained personnel to perform standardizedmore » biological assessments of culvert passability to a number of juvenile salmon species. Questions to be addressed by the research include the following: ? Do hydraulic structures such as culverts restrict habitat for juvenile salmonids? ? How do existing culverts and retrofits perform relative to juvenile salmonid passage? ? Do some culvert characteristics and hydraulic conditions provide better passage than others? ? Does the culvert represent a barrier to certain size classes of fish? Recommendations addressed issues of study site selection, initial capture, marking, recapture/observations, and estimating movement.« less

Land-cover classification in a moist tropical region of Brazil with Landsat TM imagery.

PubMed

Li, Guiying; Lu, Dengsheng; Moran, Emilio; Hetrick, Scott

2011-01-01

This research aims to improve land-cover classification accuracy in a moist tropical region in Brazil by examining the use of different remote sensing-derived variables and classification algorithms. Different scenarios based on Landsat Thematic Mapper (TM) spectral data and derived vegetation indices and textural images, and different classification algorithms - maximum likelihood classification (MLC), artificial neural network (ANN), classification tree analysis (CTA), and object-based classification (OBC), were explored. The results indicated that a combination of vegetation indices as extra bands into Landsat TM multispectral bands did not improve the overall classification performance, but the combination of textural images was valuable for improving vegetation classification accuracy. In particular, the combination of both vegetation indices and textural images into TM multispectral bands improved overall classification accuracy by 5.6% and kappa coefficient by 6.25%. Comparison of the different classification algorithms indicated that CTA and ANN have poor classification performance in this research, but OBC improved primary forest and pasture classification accuracies. This research indicates that use of textural images or use of OBC are especially valuable for improving the vegetation classes such as upland and liana forest classes having complex stand structures and having relatively large patch sizes.

Land-cover classification in a moist tropical region of Brazil with Landsat TM imagery

PubMed Central

LI, GUIYING; LU, DENGSHENG; MORAN, EMILIO; HETRICK, SCOTT

2011-01-01

This research aims to improve land-cover classification accuracy in a moist tropical region in Brazil by examining the use of different remote sensing-derived variables and classification algorithms. Different scenarios based on Landsat Thematic Mapper (TM) spectral data and derived vegetation indices and textural images, and different classification algorithms – maximum likelihood classification (MLC), artificial neural network (ANN), classification tree analysis (CTA), and object-based classification (OBC), were explored. The results indicated that a combination of vegetation indices as extra bands into Landsat TM multispectral bands did not improve the overall classification performance, but the combination of textural images was valuable for improving vegetation classification accuracy. In particular, the combination of both vegetation indices and textural images into TM multispectral bands improved overall classification accuracy by 5.6% and kappa coefficient by 6.25%. Comparison of the different classification algorithms indicated that CTA and ANN have poor classification performance in this research, but OBC improved primary forest and pasture classification accuracies. This research indicates that use of textural images or use of OBC are especially valuable for improving the vegetation classes such as upland and liana forest classes having complex stand structures and having relatively large patch sizes. PMID:22368311

Multidisciplinary Design Techniques Applied to Conceptual Aerospace Vehicle Design. Ph.D. Thesis Final Technical Report

NASA Technical Reports Server (NTRS)

Olds, John Robert; Walberg, Gerald D.

1993-01-01

Multidisciplinary design optimization (MDO) is an emerging discipline within aerospace engineering. Its goal is to bring structure and efficiency to the complex design process associated with advanced aerospace launch vehicles. Aerospace vehicles generally require input from a variety of traditional aerospace disciplines - aerodynamics, structures, performance, etc. As such, traditional optimization methods cannot always be applied. Several multidisciplinary techniques and methods were proposed as potentially applicable to this class of design problem. Among the candidate options are calculus-based (or gradient-based) optimization schemes and parametric schemes based on design of experiments theory. A brief overview of several applicable multidisciplinary design optimization methods is included. Methods from the calculus-based class and the parametric class are reviewed, but the research application reported focuses on methods from the parametric class. A vehicle of current interest was chosen as a test application for this research. The rocket-based combined-cycle (RBCC) single-stage-to-orbit (SSTO) launch vehicle combines elements of rocket and airbreathing propulsion in an attempt to produce an attractive option for launching medium sized payloads into low earth orbit. The RBCC SSTO presents a particularly difficult problem for traditional one-variable-at-a-time optimization methods because of the lack of an adequate experience base and the highly coupled nature of the design variables. MDO, however, with it's structured approach to design, is well suited to this problem. The result of the application of Taguchi methods, central composite designs, and response surface methods to the design optimization of the RBCC SSTO are presented. Attention is given to the aspect of Taguchi methods that attempts to locate a 'robust' design - that is, a design that is least sensitive to uncontrollable influences on the design. Near-optimum minimum dry weight solutions are determined for the vehicle. A summary and evaluation of the various parametric MDO methods employed in the research are included. Recommendations for additional research are provided.

Using Mobile Phone Technology in EFL Classes

ERIC Educational Resources Information Center

Sad, Süleyman Nihat

2008-01-01

Teachers of English as a foreign language (EFL) who want to develop successful lessons face numerous challenges, including large class sizes and inadequate instructional materials and technological support. Another problem is unmotivated students who refuse to participate in class activities. According to Harmer (2007), uncooperative and…

Shotgun mitogenomics across body size classes in a local assemblage of tropical Diptera: Phylogeny, species diversity and mitochondrial abundance spectrum.

PubMed

Choo, Le Qin; Crampton-Platt, Alex; Vogler, Alfried P

2017-10-01

Mitochondrial genomes can be assembled readily from shotgun-sequenced DNA mixtures of mass-trapped arthropods ("mitochondrial metagenomics"), speeding up the taxonomic characterization. Bulk sequencing was conducted on some 800 individuals of Diptera obtained by canopy fogging of a single tree in Borneo dominated by small (<1.5 mm) individuals. Specimens were split into five body size classes for DNA extraction, to equalize read numbers across specimens and to study how body size, a key ecological trait, interacts with species and phylogenetic diversity. Genome assembly produced 304 orthologous mitochondrial contigs presumed to each represent a different species. The small-bodied fraction was the by far most species-rich (187 contigs). Identification of contigs was through phylogenetic analysis together with 56 reference mitogenomes, which placed most of the Bornean community into seven clades of small-bodied species, indicating phylogenetic conservation of body size. Mapping of shotgun reads against the mitogenomes showed wide ranges of read abundances within each size class. Ranked read abundance plots were largely log-linear, indicating a uniformly filled abundance spectrum, especially for small-bodied species. Small-bodied species differed greatly from other size classes in neutral metacommunity parameters, exhibiting greater levels of immigration, besides greater total community size. We suggest that the established uses of mitochondrial metagenomics for analysis of species and phylogenetic diversity can be extended to parameterize recent theories of community ecology and biodiversity, and by focusing on the number mitochondria, rather than individuals, a new theoretical framework for analysis of mitochondrial abundance spectra can be developed that incorporates metabolic activity approximated by the count of mitochondria. © 2017 John Wiley & Sons Ltd.

Grain growth in Class I protostar Per-emb-50: a dust continuum analysis with NOEMA & SMA .

NASA Astrophysics Data System (ADS)

Agurto-Gangas, C.; Pineda, J. E.; Testi, L.; Caselli, P.; Szucs, L.; Tazzari, M.; Dunham, M.; Stephens, I. W.; Miotello, A.

A good understanding of when dust grains grow from sub-micrometer to millimeter sizes occurs is crucial for models of planet formation. This provides the first step towards the production of pebbles and planetesimals in protoplanetary disks. Thanks to detailed studies of the spectral index in Class II disks, it is well established that Class II objects have already dust grains of millimetres sizes, however, it is not clear when in the star formation process this grain growth occurs. Here, we present interferometric data from NOEMA at 3 mm and SMA at 1.3 mm of the Class I protostar, Per-emb-50, to determine the flux density spectral index at mm-wavelengths of the unresolved disk and the surrounding envelope. We find a spectral index in the unresolved disk 30% smaller than the envelope, alpha env=2.18, comparable to values obtained toward Class 0 sources.

Spatial patterns of giant sequoia (Sequoiadendron giganteum) in two sequoia groves in Sequoia National Park, California

USGS Publications Warehouse

Stohlgren, Thomas J.

1993-01-01

Although Muir Grove and Castle Creek Grove are similar in area, elevation, and number of giant sequoias, various spatial pattern analysis techniques showed that they had dissimilar spatial patterns for similar-sized trees. Two-dimensional and transect two-term local quadrat variance techniques detected general trends in the spatial patterns of different-sized trees, detected multiple-scale patterns within individual size classes, and provided information on the scale and intensity of patches of individual size classes of trees in Muir and Castle Creek groves. In Muir Grove, midsized sequoias (1.5 to 2.4 m DBH classes) had major pattern scales 350–450 m in diameter, whereas the same-sized trees in Castle Creek Grove had pattern scales >1000 m in diameter. Many size classes of trees had minor patches superimposed on larger scale patterns in both groves. There may be different recruitment patterns in core (i.e., central) areas compared with peripheral areas of sequoia groves; core areas of both groves had more small live sequoias and dead sequoias than peripheral areas of the groves. Higher densities of sequoias and, perhaps, more rapid turnover of individuals in core areas may indicate (i) differences in disturbance histories and favorability of microsites in the core and peripheral areas of groves; (ii) different responses to disturbance due to shifts in the species composition of the stand and thus, the relative influences of intra- to inter-specific competition; or (iii) slower growth or lower survivorship rates in marginal habitat (i.e., peripheral areas).

Population biology of the mangrove crab Ucides cordatus (Decapoda: Ucididae) in an estuary from semiarid northeastern Brazil.

PubMed

Leite, Marcos de Miranda Leão; Rezende, Carla Ferreira; Silva, José Roberto Feitosa

2013-12-01

The mangrove crab Ucides cordatus is an important resource of estuarine regions along the Brazilian coast. U. cordatus is distributed from Florida, U.S.A., to the coast of Santa Catarina, Brazil. The species plays an important role in processing leaf litter in the mangroves, which optimizes the processes of energy transfer and nutrient cycling, and is considered a keystone species in the ecosystem. Population declines have been reported in different parts of the Brazilian coast. In the present study we evaluated aspects of the population structure, sex ratio and size at morphological sexual maturity. We analyzed 977 specimens collected monthly over 24 months (2010-2012), in a mangrove of the Jaguaribe River, in the municipality of Aracati on the East coast of Ceará state, Northeastern Brazil. The study area has a mild semiarid tropical climate, with mean temperatures between 26 and 28 degrees C. The area is located within the eco-region of the semiarid Northeast coast, where mangroves occur in small areas and estuaries are affected by mesomareal regimes. The population structure was evaluated by the frequency distribution of size classes in each month, and the overall sex ratio was analyzed using the chi-square test. Size at morphological sexual maturity was estimated based on the allometry of the cheliped of the males and the abdomen width of the females, using the program REGRANS. The size-frequency distribution was unimodal in both sexes. The overall sex ratio (M:F) (1:0.6) was significantly different from 1:1. Analysis of the sex ratio by size class showed that the proportion of males increased significantly from size class 55-60 mm upward, and this pattern persisted in the larger size classes. In the smaller size classes the sex ratio did not differ from 1:1. The size at morphological sexual maturity was estimated at a carapace width (CW) of 52 mm and 45 mm for males and females, respectively. Analysis of the population parameters indicated that the population of U. cordatus in the Jaguaribe River mangrove is stable. However, constant monitoring of the population is required to detect any changes in the population attributes that may affect this stability.

Comparison of using single- or multi-polarimetric TerraSAR-X images for segmentation and classification of man-made maritime objects

NASA Astrophysics Data System (ADS)

Teutsch, Michael; Saur, Günter

2011-11-01

Spaceborne SAR imagery offers high capability for wide-ranging maritime surveillance especially in situations, where AIS (Automatic Identification System) data is not available. Therefore, maritime objects have to be detected and optional information such as size, orientation, or object/ship class is desired. In recent research work, we proposed a SAR processing chain consisting of pre-processing, detection, segmentation, and classification for single-polarimetric (HH) TerraSAR-X StripMap images to finally assign detection hypotheses to class "clutter", "non-ship", "unstructured ship", or "ship structure 1" (bulk carrier appearance) respectively "ship structure 2" (oil tanker appearance). In this work, we extend the existing processing chain and are now able to handle full-polarimetric (HH, HV, VH, VV) TerraSAR-X data. With the possibility of better noise suppression using the different polarizations, we slightly improve both the segmentation and the classification process. In several experiments we demonstrate the potential benefit for segmentation and classification. Precision of size and orientation estimation as well as correct classification rates are calculated individually for single- and quad-polarization and compared to each other.

Exploratory analysis of osteoarthritis progression among medication users: data from the Osteoarthritis Initiative.

PubMed

Driban, Jeffrey B; Lo, Grace H; Eaton, Charles B; Lapane, Kate L; Nevitt, Michael; Harvey, William F; McCulloch, Charles E; McAlindon, Timothy E

2016-12-01

We conducted an exploratory analysis of osteoarthritis progression among medication users in the Osteoarthritis Initiative to identify interventions or pathways that may be associated with disease modification and therefore of interest for future clinical trials. We used participants from the Osteoarthritis Initiative with annual medication inventory data between the baseline and 36-month follow-up visit ( n = 2938). Consistent medication users were defined for each medication classification as a participant reporting at all four annual visits that they were regularly using an oral prescription medication at the time of the visit. The exploratory analysis focused on medication classes with 40 or more users. The primary outcome measures were medial tibiofemoral joint space width change and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) knee pain score change (12-36-month visits). Within each knee, we explored eight comparisons between users and matched or unmatched nonusers (defined two ways). An effect size of each comparison was calculated. Medication classes had potential signals if (a) both knees had less progression among users compared with nonusers, or (b) there was less progression based on structure and symptoms in one knee. We screened 28 medication classes. Six medication classes had signals for fewer structural changes and better knee pain changes: alpha-adrenergic blockers, antilipemic (excluding statins and fibric acid), anticoagulants, selective serotonin reuptake inhibitors, antihistamines, and antineoplastic agents. Four medication classes had signals for structural changes alone: anti-estrogen (median effect size = 0.28; range = -0.41-0.64), angiotensin-converting enzyme inhibitors (median effect size = 0.13; range = -0.08-0.28), beta-adrenergic blockers (median effect size = 0.09; range = 0.01-0.30), and thyroid agents (median effect size = 0.04; range = -0.05-0.14). Thiazide diuretics had evidence for symptom modification (median effect size = -0.12; range = -0.24-0.04). Users of neurovascular, antilipemic, or hormonal interventions may have less disease progression compared with nonusers.

Transitions in Smokers' Social Networks After Quit Attempts: A Latent Transition Analysis.

PubMed

Bray, Bethany C; Smith, Rachel A; Piper, Megan E; Roberts, Linda J; Baker, Timothy B

2016-12-01

Smokers' social networks vary in size, composition, and amount of exposure to smoking. The extent to which smokers' social networks change after a quit attempt is unknown, as is the relation between quitting success and later network changes. Unique types of social networks for 691 smokers enrolled in a smoking-cessation trial were identified based on network size, new network members, members' smoking habits, within network smoking, smoking buddies, and romantic partners' smoking. Latent transition analysis was used to identify the network classes and to predict transitions in class membership across 3 years from biochemically assessed smoking abstinence. Five network classes were identified: Immersed (large network, extensive smoking exposure including smoking buddies), Low Smoking Exposure (large network, minimal smoking exposure), Smoking Partner (small network, smoking exposure primarily from partner), Isolated (small network, minimal smoking exposure), and Distant Smoking Exposure (small network, considerable nonpartner smoking exposure). Abstinence at years 1 and 2 was associated with shifts in participants' social networks to less contact with smokers and larger networks in years 2 and 3. In the years following a smoking-cessation attempt, smokers' social networks changed, and abstinence status predicted these changes. Networks defined by high levels of exposure to smokers were especially associated with continued smoking. Abstinence, however, predicted transitions to larger social networks comprising less smoking exposure. These results support treatments that aim to reduce exposure to smoking cues and smokers, including partners who smoke. Prior research has shown that social network features predict the likelihood of subsequent smoking cessation. The current research illustrates how successful quitting predicts social network change over 3 years following a quit attempt. Specifically, abstinence predicts transitions to networks that are larger and afford less exposure to smokers. This suggests that quitting smoking may expand a person's social milieu rather than narrow it. This effect, plus reduced exposure to smokers, may help sustain abstinence. © The Author 2016. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

AN ASSESSMENT OF TYPEWRITING SKILLS IN THE SECONDARY SCHOOLS OF THE STATE OF UTAH IN RELATION TO JOB ENTRY REQUIREMENTS.

ERIC Educational Resources Information Center

PEHRSON, PATSY MAY

THE PURPOSE OF THIS STUDY WAS TO DETERMINE HOW MANY SEMESTERS OF TYPEWRITING SHOULD BE OFFERED TO AN ABLE STUDENT TO ATTAIN EMPLOYABLE SKILL. THE INFLUENCE OF THE FOLLOWING FACTORS ON TYPEWRITING ACHIEVEMENT WAS STUDIED--(1) STUDENT GRADE LEVEL, (2) CLASS SIZE, (3) SCHOOL SIZE, (4) LENGTH OF CLASS PERIOD, (5) USE OF MANUAL OR ELECTRIC TYPEWRITERS,…

Stocking, Forest Type, and Stand Size Class - The Southern Forest Inventory and Analysis Unit's Calculation of Three Important Stand Descriptors

Treesearch

Dennis M. May

1990-01-01

The procedures by which the Southern Forest Inventory and Analysis unit calculates stocking from tree data collected on inventory sample plots are described in this report. Stocking is then used to ascertain two other important stand descriptors: forest type and stand size class. Inventory data for three plots from the recently completed 1989 Tennessee survey are used...

Class-Size Reduction Program Evaluation, 2000-2001. A Report to the North Carolina Department of Public Instruction.

ERIC Educational Resources Information Center

Speas, Carol

This study examined the impact of the second year of the federal class-size reduction (CSR) program in the Wake County Public School System (WCPSS), North Carolina. The 23 participating schools in the WCPSS had from 22% to 51% of their students receiving free or reduced-price lunches. In the second year, the CSR program was expanded from grades 1…

Nevada's Class-Size Reduction Program. Nevada Revised Statutes 388.700-388.730: "Program To Reduce the Pupil-Teacher Ratio." Background Paper 97-7.

ERIC Educational Resources Information Center

Sturm, H. Pepper

In 1989, the Nevada Legislature enacted the Class-Size Reduction (CSR) Act. The measure was designed to reduce the pupil-teacher ratio in the public schools, particularly in the earliest grades. The program was scheduled to proceed in several phases. The first step reduced the student-teacher ratio in selected kindergartens and first grade classes…

Abundance and Size Distribution of Cavity Trees in Second-Growth and Old-Growth Central Hardwood Forests

Treesearch

Zhaofei Fan; Stephen R. Shifley; Martin A. Spetich; Frank R. Thompson III; David R. Larsen

2005-01-01

In central hardwood forests, mean cavity-tree abundance increases with increasing standsize class (seedling/sapling, pole, sawtimber, old-growth). However, within a size class, the number of cavity trees is highly variable among 0.1-ha inventory plots. Plots in young stands are most likely to have no cavity trees, but some plots may have more than 50 cavity trees/ha....

Abundance and size distribution of cavity trees in second-growth and old-growth central hardwood forests

Treesearch

Zhaofei Fan; Stephen R. Shifley; Martin A. Spetich; Frank R. Thompson; David R. Larsen

2005-01-01

In central hardwood forests, mean cavity-tree abundance increases with increasing standsize class (seedling/sapling, pole, sawtimber, old-growth). However, within a size class, the number of cavity trees is highly variable among 0.1-ha inventory plots. Plots in young stands are most likely to have no cavity trees, but some plots may have more than 50 cavity trees/ha....

Estimating the quadratic mean diameters of fine woody debris in forests of the United States

Treesearch

Christopher W. Woodall; Vicente J. Monleon

2010-01-01

Most fine woody debris (FWD) line-intersect sampling protocols and associated estimators require an approximation of the quadratic mean diameter (QMD) of each individual FWD size class. There is a lack of empirically derived QMDs by FWD size class and species/forest type across the U.S. The objective of this study is to evaluate a technique known as the graphical...

The effect of class size in grades K-3 on adult earnings, employment, and disability status: evidence from a multi-center randomized controlled trial.

PubMed

Wilde, Elizabeth Ty; Finn, Jeremy; Johnson, Gretchen; Muennig, Peter

2011-11-01

Early education interventions have been forwarded as a means for reducing social disparities in income and health in adulthood. We explore whether a successful early education intervention, which occurred between 1985 and 1989, improved the employment rates, earnings and health of blacks relative to whites through 2008. We used data from Project STAR (Student Teacher Achievement Ratio), a four-year multi-center randomized controlled trial of reduced class sizes in Tennessee involving 11,601 students. Students were initially randomized within 79 schools to classes with 22-25 or 13-17 students. We linked subject records to Social Security Administration (SSA) earnings and disability data collected between 1997 and 2008-when the majority of subjects were between the ages of 18 and 28. We focused our analysis on annual, rather than cumulative, measures of earnings and employment because educational attainment after high school might reduce earnings through age 23. We considered three or more years of statistically significant positive (or negative) annual impacts to be a meaningful effect. Project STAR improved cognition and high school graduation rates. These benefits were primarily realized among low-income and minority students. These early education benefits did not translate into reduced disability claims in adulthood for treated subjects. However, exposure to small class size increased employment for blacks, and increased earnings for black males (p<0.05). Exposure to small classes also led to an increase in earnings for white males. However, white females exposed to small classes experienced a net decline in earnings and employment across the later years of follow up (p<0.05), offsetting any gains by white males. Exposure to small class size in grades K-3 appears to improve earnings and employment for black males and earnings for white males, while reducing employment and earnings among white females.

Nanotoxicology and nanotechnology: new findings from the NIEHS and Superfund Research Program scientific community.

PubMed

Carlin, Danielle J

2014-01-01

Nanomaterials are characterized by their small size (i.e., nanometer scale) and can be engineered from nearly any chemical substance, creating materials that differ in composition, particle size, shape, and surface coatings. These materials are often seen as a "double-edged sword" by having properties that make them potentially beneficial in product development, drug delivery, and remediation of hazardous substances, but these same properties may result in interaction with biological systems and potential effects in the environment. The National Institute of Environmental Health Sciences (NIEHS) is interested in both the potential risks associated with exposure to these materials, while harnessing the power of engineered nanomaterials to improve public health. This presentation will consist of discussion of nanoparticle studies by NIEHS researchers and the extramural community and its efforts to develop cross-agency initiatives to solve the many vexing issues associated with nanomaterials. For example, researchers from the NIEHS National Toxicology Program (NTP) are evaluating a number of nanomaterial classes in comprehensive toxicology studies. NIEHS also has an extensive extramural research grant portfolio consisting of the Nano Grand Opportunities (Nano GO) Program and NIEHS Centers for Nanotechnology Health Implications Research (NCNHIR) Consortium consisting of U19 and U01 Cooperative Centers. Furthermore, the NIEHS Superfund Research Program (SRP), which supports a network of university (P42, R01), small business (SBIR/STTR), and training grants (R25), provides funding to grantees evaluating the toxicology of nanomaterials, developing new or improved nanotechnologies to monitor and remediate hazardous substances, and training professionals in the use of these of materials. The NIEHS's Worker Education Branch also offers educational materials for training workers on risks of nanotechnology in laboratories, manufacturing facilities, at hazardous waste cleanup sites, and during emergency responses. In conclusion, this presentation will stimulate dialogue regarding the need for more research on these complex materials and serve as a resource about the wide variety of ongoing studies on nanomaterials at NIEHS that will contribute to the determination of risk associated with this class of compounds.

Matrix models for size-structured populations: unrealistic fast growth or simply diffusion?

PubMed

Picard, Nicolas; Liang, Jingjing

2014-01-01

Matrix population models are widely used to study population dynamics but have been criticized because their outputs are sensitive to the dimension of the matrix (or, equivalently, to the class width). This sensitivity is concerning for the population growth rate (λ) because this is an intrinsic characteristic of the population that should not depend on the model specification. It has been suggested that the sensitivity of λ to matrix dimension was linked to the existence of fast pathways (i.e. the fraction of individuals that systematically move up a class), whose proportion increases when class width increases. We showed that for matrix population models with growth transition only from class i to class i + 1, λ was independent of the class width when the mortality and the recruitment rates were constant, irrespective of the growth rate. We also showed that if there were indeed fast pathways, there were also in about the same proportion slow pathways (i.e. the fraction of individuals that systematically remained in the same class), and that they jointly act as a diffusion process (where diffusion here is the movement in size of an individual whose size increments are random according to a normal distribution with mean zero). For 53 tree species from a tropical rain forest in the Central African Republic, the diffusion resulting from common matrix dimensions was much stronger than would be realistic. Yet, the sensitivity of λ to matrix dimension for a class width in the range 1-10 cm was small, much smaller than the sampling uncertainty on the value of λ. Moreover, λ could either increase or decrease when class width increased depending on the species. Overall, even if the class width should be kept small enough to limit diffusion, it had little impact on the estimate of λ for tree species.

Temperature-Correlated Changes in Phytoplankton Community Structure Are Restricted to Polar Waters.

PubMed

Ward, Ben A

2015-01-01

Globally distributed observations of size-fractionated chlorophyll a and temperature were used to incorporate temperature dependence into an existing semi-empirical model of phytoplankton community size structure. The additional temperature-dependent term significantly increased the model's ability to both reproduce and predict observations of chlorophyll a size-fractionation at temperatures below 2°C. The most notable improvements were in the smallest (picoplankton) size-class, for which overall model fit was more than doubled, and predictive skill was increased by approximately 40%. The model was subsequently applied to generate global maps for three phytoplankton size classes, on the basis of satellite-derived estimates of surface chlorophyll a and sea surface temperature. Polar waters were associated with marked decline in the chlorophyll a biomass of the smallest cells, relative to lower latitude waters of equivalent total chlorophyll a. In the same regions a complementary increase was seen in the chlorophyll a biomass of larger size classes. These findings suggest that a warming and stratifying ocean will see a poleward expansion of the habitat range of the smallest phytoplankton, with the possible displacement of some larger groups that currently dominate. There was no evidence of a strong temperature dependence in tropical or sub-tropical regions, suggesting that future direct temperature effects on community structure at lower latitudes may be small.

Effects of structural marsh management and salinity on invertebrate prey of waterbirds in marsh ponds during winter on the Gulf Coast Chenier Plain

USGS Publications Warehouse

Bolduc, F.; Afton, A.D.

2003-01-01

Aquatic invertebrates are important food resources for wintering waterbirds, and prey selection generally is limited by prey size. Aquatic invertebrate communities are influenced by sediments and hydrologic characteristics of wetlands, which were affected by structural marsh management (levees, water-control structures and impoundments; SMM) and salinity on the Gulf Coast Chenier Plain of North America. Based on previous research, we tested general predictions that SMM reduces biomass of infaunal invertebrates and increases that of epifaunal invertebrates and those that tolerate low levels of dissolved oxygen (O2) and salinity. We also tested the general prediction that invertebrate biomass in freshwater, oligohaline, and mesohaline marshes are similar, except for taxa adapted to specific ranges of salinity. Finally, we investigated relationships among invertebrate biomass and sizes, sediment and hydrologic variables, and marsh types. Accordingly, we measured biomass of common invertebrate by three size classes (63 to 199 ??m, 200 to 999 ??m, and ???1000 ??m), sediment variables (carbon content, C:N ratio, hardness, particle size, and O, penetration), and hydrologic variables (salinity, water depth,temperature, 02, and turbidity) in ponds of impounded freshwater (IF), oligohaline (IO), mesohaline (IM), and unimpounded mesohaline (UM) marshes during winters 1997-1998 to 1999-2000 on Rockefeller State Wildlife Refuge, near Grand Chenier, Louisiana, USA. As predicted, an a priori multivariate analysis of variance (MANOVA) contrast indicated that biomass of an infaunal class of invertebrates (Nematoda, 63 to 199 ??m) was greater in UM marsh ponds than in those of IM marshes, and biomass of an epifaunal class of invertebrates (Ostracoda, 200 to 999 ??m) was greater in IM marsh ponds than in those of UM marshes. The observed reduction in Nematoda due to SMM also was consistent with the prediction that SMM reduces invertebrates that do not tolerate low salinity. Furthermore, as predicted, an a priori MANOVA contrast indicated that biomass of a single invertebrate class adapted to low salinity (Oligochaeta, 200 to 999 ??m) was greater in ponds of IF marshes than in those of IO and IM marshes. A canonical correspondence analysis indicated that variation in salinity and O2 penetration best explained differences among sites that maximized biomass of the common invertebrate classes. Salinity was positively correlated with the silt-clay fraction, O2, and O2 penetration, and negatively correlated with water depth, sediment hardness, carbon, and C:N. Nematoda, Foraminifera, and Copepoda generally were associated with UM marsh ponds and high salinity, whereas other invertebrate classes were distributed among impounded marsh ponds and associated with lower salinity. Our results suggest that SMM and salinity have relatively small effects on invertebrate prey of wintering waterbirds in marsh ponds because they affect biomass of Nematoda and Oligochaeta, and few waterbirds consume these invertebrates. ?? 2003, The Society of Wetland Scientists.

How long does a mindfulness-based stress reduction program need to be? A review of class contact hours and effect sizes for psychological distress.

PubMed

Carmody, James; Baer, Ruth A

2009-06-01

The mindfulness-based stress reduction (MBSR) program was designed to be long enough for participants to grasp the principles of self-regulation through mindfulness and develop skill and autonomy in mindfulness practice. It traditionally consists of 26 hours of session time including eight classes of 2-1/2 hours and an all-day class. The circumstances of some groups exclude them from participating in this standard form and a number of trials have evaluated programs with abbreviated class time. If lower program time demands can lead to similar outcomes in psychological functioning, it would support their utility in these settings and might lead to greater participation. However, the effect of variation in class hours on outcomes has not been systematically studied. To obtain preliminary information related to this question we examined effect sizes for psychological outcome variables in published studies of MBSR, some of which had adapted the standard number of class hours. The correlation between mean effect size and number of in-class hours was nonsignificant for both clinical and nonclinical samples and suggests that adaptations that include less class time may be worthwhile for populations for whom reduction of psychological distress is an important goal and for whom longer time commitment may be a barrier to their ability or willingness to participate. However, the standard MBSR format has accrued the most empirical support for its efficacy and session time may be important to the development of other kinds of program outcomes. The result points to the importance of empirical studies systematically examining this question. Copyright 2009 Wiley Periodicals, Inc.

Multilevel latent class casemix modelling: a novel approach to accommodate patient casemix.

PubMed

Gilthorpe, Mark S; Harrison, Wendy J; Downing, Amy; Forman, David; West, Robert M

2011-03-01

Using routinely collected patient data we explore the utility of multilevel latent class (MLLC) models to adjust for patient casemix and rank Trust performance. We contrast this with ranks derived from Trust standardised mortality ratios (SMRs). Patients with colorectal cancer diagnosed between 1998 and 2004 and resident in Northern and Yorkshire regions were identified from the cancer registry database (n = 24,640). Patient age, sex, stage-at-diagnosis (Dukes), and Trust of diagnosis/treatment were extracted. Socioeconomic background was derived using the Townsend Index. Outcome was survival at 3 years after diagnosis. MLLC-modelled and SMR-generated Trust ranks were compared. Patients were assigned to two classes of similar size: one with reasonable prognosis (63.0% died within 3 years), and one with better prognosis (39.3% died within 3 years). In patient class one, all patients diagnosed at stage B or C died within 3 years; in patient class two, all patients diagnosed at stage A, B or C survived. Trusts were assigned two classes with 51.3% and 53.2% of patients respectively dying within 3 years. Differences in the ranked Trust performance between the MLLC model and SMRs were all within estimated 95% CIs. A novel approach to casemix adjustment is illustrated, ranking Trust performance whilst facilitating the evaluation of factors associated with the patient journey (e.g. treatments) and factors associated with the processes of healthcare delivery (e.g. delays). Further research can demonstrate the value of modelling patient pathways and evaluating healthcare processes across provider institutions.

Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud

NASA Astrophysics Data System (ADS)

Sheehan, Patrick D.; Eisner, Josh A.

2017-12-01

Class I protostars are thought to represent an early stage in the lifetime of protoplanetary disks, when they are still embedded in their natal envelope. Here we measure the disk masses of 10 Class I protostars in the Taurus Molecular Cloud to constrain the initial mass budget for forming planets in disks. We use radiative transfer modeling to produce synthetic protostar observations and fit the models to a multi-wavelength data set using a Markov Chain Monte Carlo fitting procedure. We fit these models simultaneously to our new Combined Array for Research in Millimeter-wave Astronomy 1.3 mm observations that are sensitive to the wide range of spatial scales that are expected from protostellar disks and envelopes so as to be able to distinguish each component, as well as broadband spectral energy distributions compiled from the literature. We find a median disk mass of 0.018 {M}ȯ on average, more massive than the Taurus Class II disks, which have median disk mass of ∼ 0.0025 {M}ȯ . This decrease in disk mass can be explained if dust grains have grown by a factor of 75 in grain size, indicating that by the Class II stage, at a few Myr, a significant amount of dust grain processing has occurred. However, there is evidence that significant dust processing has occurred even during the Class I stage, so it is likely that the initial mass budget is higher than the value quoted here.

Aggregate distribution and associated organic carbon influenced by cover crops

NASA Astrophysics Data System (ADS)

Barquero, Irene; García-González, Irene; Benito, Marta; Gabriel, Jose Luis; Quemada, Miguel; Hontoria, Chiquinquirá

2013-04-01

Replacing fallow with cover crops during the non-cropping period seems to be a good alternative to diminish soil degradation by enhancing soil aggregation and increasing organic carbon. The aim of this study was to analyze the effect of replacing fallow by different winter cover crops (CC) on the aggregate distribution and C associated of an Haplic Calcisol. The study area was located in Central Spain, under semi-arid Mediterranean climate. A 4-year field trial was conducted using Barley (Hordeum vulgare L.) and Vetch (Vicia sativa L.) as CC during the intercropping period of maize (Zea mays L.) under irrigation. All treatments were equally irrigated and fertilized. Maize was directly sown over CC residues previously killed in early spring. Composite samples were collected at 0-5 and 5-20 cm depths in each treatment on autumn of 2010. Soil samples were separated by wet sieving into four aggregate-size classes: large macroaggregates ( >2000 µm); small macroaggregates (250-2000 µm); microaggregates (53-250 µm); and < 53 µm (silt + clay size). Organic carbon associated to each aggregate-size class was measured by Walkley-Black Method. Our preliminary results showed that the aggregate-size distribution was dominated by microaggregates (48-53%) and the <53 µm fraction (40-44%) resulting in a low mean weight diameter (MWD). Both cover crops increased aggregate size resulting in a higher MWD (0.28 mm) in comparison with fallow (0.20 mm) in the 0-5 cm layer. Barley showed a higher MWD than fallow also in 5-20 cm layer. Organic carbon concentrations in aggregate-size classes at top layer followed the order: large macroaggregates > small macroaggregates > microaggregates > silt + clay size. Treatments did not influence C concentration in aggregate-size classes. In conclusion, cover crops improved soil structure increasing the proportion of macroaggregates and MWD being Barley more effective than Vetch at subsurface layer.

Moving toward change: Institutionalizing reform through implementation of the Learning Assistant model and Open Source Tutorials

NASA Astrophysics Data System (ADS)

Goertzen, Renee Michelle; Brewe, Eric; Kramer, Laird H.; Wells, Leanne; Jones, David

2011-12-01

Florida International University has undergone a reform in the introductory physics classes by focusing on the laboratory component of these classes. We present results from the secondary implementation of two research-based instructional strategies: the implementation of the Learning Assistant model as developed by the University of Colorado at Boulder and the Open Source Tutorial curriculum developed at the University of Maryland, College Park. We examine the results of the Force Concept Inventory (FCI) for introductory students over five years (n=872) and find that the mean raw gain of students in transformed lab sections was 0.243, while the mean raw gain of the traditional labs was 0.159, with a Cohen’s d effect size of 0.59. Average raw gains on the FCI were 0.243 for Hispanic students and 0.213 for women in the transformed labs, indicating that these reforms are not widening the gaps between underrepresented student groups and majority groups. Our results illustrate how research-based instructional strategies can be successfully implemented in a physics department with minimal department engagement and in a sustainable manner.

Fishing and temperature effects on the size structure of exploited fish stocks.

PubMed

Tu, Chen-Yi; Chen, Kuan-Ting; Hsieh, Chih-Hao

2018-05-08

Size structure of fish stock plays an important role in maintaining sustainability of the population. Size distribution of an exploited stock is predicted to shift toward small individuals caused by size-selective fishing and/or warming; however, their relative contribution remains relatively unexplored. In addition, existing analyses on size structure have focused on univariate size-based indicators (SBIs), such as mean length, evenness of size classes, or the upper 95-percentile of the length frequency distribution; these approaches may not capture full information of size structure. To bridge the gap, we used the variation partitioning approach to examine how the size structure (composition of size classes) responded to fishing, warming and the interaction. We analyzed 28 exploited stocks in the West US, Alaska and North Sea. Our result shows fishing has the most prominent effect on the size structure of the exploited stocks. In addition, the fish stocks experienced higher variability in fishing is more responsive to the temperature effect in their size structure, suggesting that fishing may elevate the sensitivity of exploited stocks in responding to environmental effects. The variation partitioning approach provides complementary information to univariate SBIs in analyzing size structure.

Achievement Flourishes in Larger Classes: Secondary School Students in Most Countries Achieved Better Literacy in Larger Classes

ERIC Educational Resources Information Center

Alharbi, Abeer A.; Stoet, Gijsbert

2017-01-01

There is no consensus among academics about whether children benefit from smaller classes. We analysed the data from the 2012 Programme for International Student Assessment (PISA) to test if smaller classes lead to higher performance. Advantages of using this data set are not only its size (478,120 15-year old students in 63 nations) and…

Patterns of co-occurring addictions, posttraumatic stress disorder, and major depressive disorder in detoxification treatment seekers: Implications for improving detoxification treatment outcomes.

PubMed

Anderson, RaeAnn E; Hruska, Bryce; Boros, Alec P; Richardson, Christopher J; Delahanty, Douglas L

2018-03-01

Poly-substance use and psychiatric comorbidity are common among individuals receiving substance detoxification services. Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are the most common co-occurring psychiatric disorders with substance use disorder (SUD). Current treatment favors a one-size-fits-all approach to treating addiction focusing on one substance or one comorbidity. Research examining patterns of substance use and comorbidities can inform efforts to effectively identify and differentially treat individuals with co-occurring conditions. Using latent class analysis, the current study identified four patterns of PTSD, MDD, and substance use among 375 addiction treatment seekers receiving medically supervised detoxification. The four identified classes were: 1) a PTSD-MDD-Poly SUD class characterized by PTSD and MDD occurring in the context of opioid, cannabis, and tobacco use disorders; 2) an MDD-Poly SUD class characterized by MDD and alcohol, opioid, tobacco, and cannabis use disorders; 3) an alcohol-tobacco class characterized by alcohol and tobacco use disorders; and 4) an opioid-tobacco use disorder class characterized by opioid and tobacco use disorders. The observed classes differed on gender and clinical characteristics including addiction severity, trauma history, and PTSD/MDD symptom severity. The observed classes likely require differing treatment approaches. For example, people in the PTSD-MDD-Poly SUD class would likely benefit from treatment approaches targeting anxiety sensitivity and distress tolerance, while the opioid-tobacco class would benefit from treatments that incorporate motivational interviewing. Appropriate matching of treatment to class could optimize treatment outcomes for polysubstance and comorbid psychiatric treatment seekers. These findings also underscore the importance of well-developed referral networks to optimize outpatient psychotherapy for detoxification treatment-seekers to enhance long-term recovery, particularly those that include transdiagnostic treatment components. Copyright © 2017. Published by Elsevier Inc.

Class Sizes and Dissadvantaged Schools.

ERIC Educational Resources Information Center

Warner, David

1978-01-01

Describes a program in which smaller class groups for socially and culturally deprived children resulted in enhanced social attitudes and more responsive, mature behavior in interaction with both adults and peers. (Author/IRT)

Transitions in Smokers’ Social Networks After Quit Attempts: A Latent Transition Analysis

PubMed Central

Smith, Rachel A.; Piper, Megan E.; Roberts, Linda J.; Baker, Timothy B.

2016-01-01

Introduction: Smokers’ social networks vary in size, composition, and amount of exposure to smoking. The extent to which smokers’ social networks change after a quit attempt is unknown, as is the relation between quitting success and later network changes. Methods: Unique types of social networks for 691 smokers enrolled in a smoking-cessation trial were identified based on network size, new network members, members’ smoking habits, within network smoking, smoking buddies, and romantic partners’ smoking. Latent transition analysis was used to identify the network classes and to predict transitions in class membership across 3 years from biochemically assessed smoking abstinence. Results: Five network classes were identified: Immersed (large network, extensive smoking exposure including smoking buddies), Low Smoking Exposure (large network, minimal smoking exposure), Smoking Partner (small network, smoking exposure primarily from partner), Isolated (small network, minimal smoking exposure), and Distant Smoking Exposure (small network, considerable nonpartner smoking exposure). Abstinence at years 1 and 2 was associated with shifts in participants’ social networks to less contact with smokers and larger networks in years 2 and 3. Conclusions: In the years following a smoking-cessation attempt, smokers’ social networks changed, and abstinence status predicted these changes. Networks defined by high levels of exposure to smokers were especially associated with continued smoking. Abstinence, however, predicted transitions to larger social networks comprising less smoking exposure. These results support treatments that aim to reduce exposure to smoking cues and smokers, including partners who smoke. Implications: Prior research has shown that social network features predict the likelihood of subsequent smoking cessation. The current research illustrates how successful quitting predicts social network change over 3 years following a quit attempt. Specifically, abstinence predicts transitions to networks that are larger and afford less exposure to smokers. This suggests that quitting smoking may expand a person’s social milieu rather than narrow it. This effect, plus reduced exposure to smokers, may help sustain abstinence. PMID:27613925

What Doesn't Work for Whom? Exploring Heterogeneity in Responsiveness to the Family Check-Up in Early Childhood Using a Mixture Model Approach.

PubMed

Pelham, William E; Dishion, Thomas J; Tein, Jenn-Yun; Shaw, Daniel S; Wilson, Melvin N

2017-11-01

This study applied latent class analysis to a family-centered prevention trial in early childhood to identify subgroups of families with differential responsiveness to the Family Check-Up (FCU) intervention. The sample included 731 families with 2-year-olds randomized to the FCU or control condition and followed through age 5 with yearly follow-up assessments. A two-step mixture model was used to examine whether specific constellations of family characteristics at age 2 (baseline) were related to intervention response across ages 3, 4, and 5. The first step empirically identified latent classes of families based on several family risk and adjustment variables selected on the basis of previous research. The second step modeled the effect of the FCU on longitudinal change in children's problem behavior in each of the empirically derived latent classes. Results suggested a five-class solution, where a significant intervention effect of moderate to large size was observed in one of the five classes-the class characterized by child neglect, legal problems, and parental mental health issues. Pairwise comparisons revealed that the intervention effect was significantly greater in this class of families than in two other classes that were generally less at risk for the development of child disruptive behavior problems, albeit still low-income. Thus, findings suggest that (a) the FCU is most successful in reducing child problem behavior in more highly distressed, low-income families, and (b) the FCU may have little impact for relatively low-risk, low-income families. Future directions include the development of a brief screening process that can triage low-income families into groups that should be targeted for intervention, redirected to other services, monitored prospectively, or left alone.

Cosmic evolution of non-topological solitons, paper 1

NASA Technical Reports Server (NTRS)

Frieman, Joshua A.; Olinto, Angela V.; Gleiser, Marcelo; Alcock, Charles

1989-01-01

Nontopological solitons are stable field configurations which may be formed in a primordial phase transition. Their cosmic evolution is studied, and the possibility that such objects could contribute significantly to the energy density of the Universe is examined. As the Universe cools, initially all but the largest lumps evaporate into free particles; those which survive may subsequently enter a brief accretion phase before they freeze out at a final size. Although the minimum critical charges which survive depend on particle masses and couplings, researchers develop an analysis which applies to a wide class of models. In most cases, solitons of moderate size survive the evaporation process only if there is a significant charge asymmetry or if they form at a temperature well below their binding energy per charge.

Measurement of variation in soil solute tracer concentration across a range of effective pore sizes

USGS Publications Warehouse

Harvey, Judson W.

1993-01-01

Solute transport concepts in soil are based on speculation that solutes are distributed nonuniformly within large and small pores. Solute concentrations have not previously been measured across a range of pore sizes and examined in relation to soil hydrological properties. For this study, modified pressure cells were used to measure variation in concentration of a solute tracer across a range of pore sizes. Intact cores were removed from the site of a field tracer experiment, and soil water was eluted from 10 or more discrete classes of pore size. Simultaneous changes in water content and unsaturated hydraulic conductivity were determined on cores using standard pressure cell techniques. Bromide tracer concentration varied by as much as 100% across the range of pore sizes sampled. Immediately following application of the bromide tracer on field plots, bromide was most concentrated in the largest pores; concentrations were lower in pores of progressively smaller sizes. After 27 days, bromide was most dilute in the largest pores and concentrations were higher in the smaller pores. A sharp, threefold decrease in specific water capacity during elution indicated separation of two major pore size classes at a pressure of 47 cm H2O and a corresponding effective pore diameter of 70 μm. Variation in tracer concentration, on the other hand, was spread across the entire range of pore sizes investigated in this study. A two-porosity characterization of the transport domain, based on water retention criteria, only broadly characterized the pattern of variation in tracer concentration across pore size classes during transport through a macroporous soil.

The Evolution of Qualitative and Quantitative Research Classes when Delivered via Distance Education.

ERIC Educational Resources Information Center

Hecht, Jeffrey B.; Klass, Patricia H.

This study examined whether new streamed Internet audio and video technology could be used for primary instruction in off-campus research classes. Several different off-campus student cohorts at Illinois State university enrolled in both a fall semester qualitative research methods class and a spring semester quantitative research methods class.…

Nanodiamonds: The ways forward

NASA Astrophysics Data System (ADS)

Tamburri, Emanuela; Orlanducci, Silvia; Reina, Giacomo; Lavecchia, Teresa; Angjellari, Mariglen; Rossi, Marco; Terranova, Maria Letizia

2015-06-01

We present here a short overview of the main classes of methods used to generate diamond nanostructures. The described methodologies, namely the CVD techniques, the explosive reactions, the laser-induced processes and the plasma treatments, offer the feasibility to produce nanosized diamonds in forms of powders or films, to modulate size, shape and structure of individual nanograins or of nanodiamond aggregates, to build complex architectures. A proper design and a subsequent controlled production of diamond structures at the nanoscale are strict requirements for the transition from fundamental material research to real-world applications.

The relationship of blue crab (Callinectes sapidus) size class and molt stage to disease acquisition and intensity of Hematodinium perezi infections.

PubMed

Lycett, Kristen A; Chung, J Sook; Pitula, Joseph S

2018-01-01

In the blue crab, Callinectes sapidus, early studies suggested a relationship between smaller crabs, which molt more frequently, and higher rates of infection by the dinoflagellate parasite, Hematodinium perezi. In order to better explore the influence of size and molting on infections, blue crabs were collected from the Maryland coastal bays and screened for the presence of H. perezi in hemolymph samples using a quantitative PCR assay. Molt stage was determined by a radioimmunoassay which measured ecdysteroid concentrations in blue crab hemolymph. Differences were seen in infection prevalence between size classes, with the medium size class (crabs 61 to 90 mm carapace width) and juvenile crabs (≤ 30 mm carapace width) having the highest infection prevalence at 47.2% and 46.7%, respectively. All size classes were susceptible to infection, although fall months favored disease acquisition by juveniles, whereas mid-sized animals (31-90 mm carapace width) acquired infection predominantly in summer. Disease intensity was also most pronounced in the summer, with blue crabs > 61 mm being primary sources of proliferation. Molt status appeared to be influenced by infection, with infected crabs having significantly lower concentrations of ecdysteroids than uninfected crabs in the spring and the fall. We hypothesize that infection by H. perezi may increase molt intervals, with a delay in the spring molt cycle as an evolutionary adaptation functioning to coincide with increased host metabolism, providing optimal conditions for H. perezi propagation. Regardless of season, postmolt crabs harbored significantly higher proportions of moderate and heavy infections, suggesting that the process of ecdysis, and the postmolt recovery period, has a positive effect on parasite proliferation.

School Facility Recommendations for Class Size Reduction.

ERIC Educational Resources Information Center

Evans, Ann M.

The California Department of Education encourages its school districts to make every effort to reduce classroom size and maintain the physical size of 960 square feet for elementary schools and 1,350 square feet for kindergartens. This report examines the Code of Regulations relative to classroom size in elementary, kindergarten, and special…

The influence of a yoga exercise program for young adults with intellectual disabilities.

PubMed

Hawkins, Brent L; Stegall, Joanna B; Weber, Madalyn F; Ryan, Joseph B

2012-07-01

Individuals with intellectual disabilities (ID) have an increased risk of obesity and are significantly less likely to engage in physical activity compared to their nondisabled peers. A growing body of research supports the physical and mental health benefits of yoga. While the benefits of yoga have been studied across a host of populations with varying ages and physical disabilities, no studies could be identified investigating the benefits of yoga for young adults with ID. This study investigated the impact of participating in yoga classes on the amount of exercise behavior and perception of physical exertion when compared to non-structured exercise sessions between two young adults with ID in a post-secondary education setting. A single subject multiple baseline research design was implemented across two young adults with mild ID to determine the effects of a yoga exercise class on frequency of exercise behavior and perception of physical exertion when compared to non-structured exercise sessions. Partial interval recording, the Eston-Parfitt curvilinear rating of perceived exertion scale, and the physical activity enjoyment scale were implemented to collect data on dependent variables and consumer satisfaction during each non-structured exercise session and each yoga class. indicated that percentage of exercise behavior and perceived exertion levels during yoga group exercise sharply increased with large effect sizes when compared to non-structured exercise sessions.

Research-Based Assessment of Students' Beliefs about Experimental Physics: When is Gender a Factor?

NASA Astrophysics Data System (ADS)

Wilcox, Bethany R.; Lewandowski, H. J.

2016-12-01

The existence of gender differences in student performance on conceptual assessments and their responses to attitudinal assessments has been repeatedly demonstrated. This difference is often present in students' preinstruction responses and persists in their postinstruction responses. However, one area in which the presence of gender differences has not been extensively explored is undergraduate laboratory courses. For example, one of the few laboratory focused research-based assessments, the Colorado Learning Attitudes about Science Survey for Experimental Physics (E-CLASS), has not been tested for the existence of gender differences in students' responses. Here, we utilize a national data set of responses to the E-CLASS to determine if they demonstrate significant gender differences. We also investigate how these differences vary along multiple student and course demographic slices, including course level (first-year vs beyond-first-year) and major (physics vs nonphysics). We observe a gender gap in pre- and postinstruction E-CLASS scores in the aggregate data both for the overall score and for most items individually. However, for some subpopulations (e.g., beyond-first-year students) the size or even existence of the gender gap depends on another dimension (e.g., student major). We also find that for all groups the gap in postinstruction scores vanishes or is greatly reduced when controlling for preinstruction scores, course level, and student major.

Crown-root morphology of lower incisors in patients with class III malocclusion.

PubMed

Wang, Bo; Shen, Guofang; Fang, Bing; Zhang, Li

2012-07-01

The purpose of this study was to investigate the crown-root morphology of lower incisors in patients with class III malocclusion using cone-beam computed tomography. Cone-beam computed tomography images were analyzed from 53 adult class I patients (group 1), 37 preadolescent class III patients (group 2), and 66 adult class III patients (group 3) comprising 3 divisions (divisions 1, 2, and 3 corresponded to mild, moderate, and severe class III malocclusions). The size and crown-root angulations of lower incisors in different groups and divisions were statistically appraised with group 1 used as the control group. No significant differences were found for the size of lower incisors among different groups and divisions (P > 0.05). Compared with group 1, the crown-root angulations of lower incisors in groups 2 and 3 were significantly larger (P < 0.01), and among 3 divisions, the lower incisors of division 3 rather than divisions 2 and 3 exhibited larger crown-root angulations (P < 0.01). Attention should be paid to the enlarged crown-root angulations of lower incisors in class III patients during orthodontic and orthognathic treatment, especially in severe ones.

Digital image processing of nanometer-size metal particles on amorphous substrates

NASA Technical Reports Server (NTRS)

Soria, F.; Artal, P.; Bescos, J.; Heinemann, K.

1989-01-01

The task of differentiating very small metal aggregates supported on amorphous films from the phase contrast image features inherently stemming from the support is extremely difficult in the nanometer particle size range. Digital image processing was employed to overcome some of the ambiguities in evaluating such micrographs. It was demonstrated that such processing allowed positive particle detection and a limited degree of statistical size analysis even for micrographs where by bare eye examination the distribution between particles and erroneous substrate features would seem highly ambiguous. The smallest size class detected for Pd/C samples peaks at 0.8 nm. This size class was found in various samples prepared under different evaporation conditions and it is concluded that these particles consist of 'a magic number' of 13 atoms and have cubooctahedral or icosahedral crystal structure.

Student Achievement in Large-Lecture Remedial Math Classes

ERIC Educational Resources Information Center

Monte, Brent M.

2011-01-01

Due to the increase in students seeking remedial math classes at the community college level, coupled with declining revenues to the community colleges and a lack of classroom availability, the need to consider increasing class size has become a relevant and timely issue. This study is a mixed-method, quasi-experimental study testing effects of…

76 FR 32257 - Small Business Size Standards; Waiver of the Nonmanufacturer Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-03

... AGENCY: U.S. Small Business Administration. ACTION: Notice of proposed retraction of a Class Waiver from...: The U.S. Small Business Administration (SBA) is proposing the retraction of a class waiver from the... retraction of the class waiver from the Nonmanufacturer Rule for PSC 9130 (Liquid Propellants--Petroleum Base...

Teaching Large Classes in Higher Education. How To Maintain Quality with Reduced Resources.

ERIC Educational Resources Information Center

Gibbs, Graham, Ed.; Jenkins, Alan, Ed.

This publication seeks to give practical assistance to teachers and administrators responsible for teaching large classes at collges and universities in the United Kingdom. Areas covered include class size, problems related to learning and teaching, teaching strategies in specific disciplines, field study experience and other subjects. The 12…

Intensive Education: How It Affects Teachers' and Students' Work Conditions.

ERIC Educational Resources Information Center

Fallon, Karin

This qualitative study of a high school using intensive education shows how teaching and learning were improved when teachers taught and students attended one class daily for 6 weeks. Intensive education is an alternative scheduling and organizational format that reduces class size and extends class length by having teachers and students in one…

Tattoo inks in general usage contain nanoparticles.

PubMed

Høgsberg, T; Loeschner, K; Löf, D; Serup, J

2011-12-01

To our knowledge tattooing has never been thought of as a method of introducing nanoparticles (NPs) into the human body by the intradermal route, and as such it has never been a topic of research in nanotoxicology. The content of NPs in tattoo inks is unknown. To classify the particle sizes in tattoo inks in general usage. The particle size was measured by laser diffraction, electron microscopy and X-ray diffraction. The size of the pigments could be divided into three main classes. The black pigments were the smallest, the white pigments the largest and the coloured pigments had a size in between the two. The vast majority of the tested tattoo inks contained significant amounts of NPs except for the white pigments. The black pigments were almost pure NPs, i.e. particles with at least one dimension <100 nm. The finding of NPs in tattoo inks in general usage is new and may contribute to the understanding of tattoo ink kinetics. How the body responds to NP tattoo pigments should be examined further. © 2011 The Authors. BJD © 2011 British Association of Dermatologists.

Size-dependent selective mechanisms on males and females and the evolution of sexual size dimorphism in frogs.

PubMed

Nali, Renato C; Zamudio, Kelly R; Haddad, Célio F B; Prado, Cynthia P A

2014-12-01

Sexual size dimorphism (SSD) varies in animals from male biased to female biased. The evolution of SSD is potentially influenced by a number of factors, such as territoriality, fecundity, and temporal breeding patterns (explosive vs. prolonged). In general, frogs show female-biased SSD with broad variance among species. Using comparative methods, we examine how different selective forces affect male and female sizes, and we test hypotheses about size-dependent mechanisms shaping SSD in frogs. Male size was weakly associated with SSD in all size classes, and we found no significant association among SSD, male size, temporal breeding pattern, and male territoriality. In contrast, female size best explained SSD variation across all size classes but especially for small-bodied species. We found a stronger evolutionary association between female body size and fecundity, and this fecundity advantage was highest in explosively breeding species. Our data indicate that the fecundity advantage associated with female body size may not be linear, such that intermediate and large females benefit less with body size increases. Therefore, size-dependent selection in females associated with fecundity and breeding patterns is an important mechanism driving SSD evolution in frogs. Our study underscores the fact that lineage-specific ecology and behavior should be incorporated in comparative analyses of animal SSD.

Ultrasonic device for real-time sewage velocity and suspended particles concentration measurements.

PubMed

Abda, F; Azbaid, A; Ensminger, D; Fischer, S; François, P; Schmitt, P; Pallarès, A

2009-01-01

In the frame of a technological research and innovation network in water and environment technologies (RITEAU, Réseau de Recherche et d'Innovation Technologique Eau et Environnement), our research group, in collaboration with industrial partners and other research institutions, has been in charge of the development of a suitable flowmeter: an ultrasonic device measuring simultaneously the water flow and the concentration of size classes of suspended particles. Working on the pulsed ultrasound principle, our multi-frequency device (1 to 14 MHz) allows flow velocity and water height measurement and estimation of suspended solids concentration. Velocity measurements rely on the coherent Doppler principle. A self developed frequency estimator, so called Spectral Identification method, was used and compared to the classical Pulse-Pair method. Several measurements campaigns on one wastewater collector of the French city of Strasbourg gave very satisfactory results and showed smaller standard deviation values for the Doppler frequency extracted by the Spectral Identification method. A specific algorithm was also developed for the water height measurements. It relies on the water surface acoustic impedance rupture and its peak localisation and behaviour in the collected backscattering data. This algorithm was positively tested on long time measurements on the same wastewater collector. A large part of the article is devoted to the measurements of the suspended solids concentrations. Our data analysis consists in the adaptation of the well described acoustic behaviour of sand to the behaviour of wastewater particles. Both acoustic attenuation and acoustic backscattering data over multiple frequencies are analyzed for the extrapolation of size classes and respective concentrations. Under dry weather conditions, the massic backscattering coefficient and the overall size distribution showed similar evolution whatever the measurement site was and were suggesting a global wastewater particles behaviour. By comparison to sampling data, our data analysis lead to the characterization of two particle groups: the ones occurring during rain events and the ones typical of wastewater under dry weather conditions. Even with already encouraging results on the several weeks of data recorded on several wastewater collectors, the validation of our data inversion method is still under progress.

An expert system based software sizing tool, phase 2

NASA Technical Reports Server (NTRS)

Friedlander, David

1990-01-01

A software tool was developed for predicting the size of a future computer program at an early stage in its development. The system is intended to enable a user who is not expert in Software Engineering to estimate software size in lines of source code with an accuracy similar to that of an expert, based on the program's functional specifications. The project was planned as a knowledge based system with a field prototype as the goal of Phase 2 and a commercial system planned for Phase 3. The researchers used techniques from Artificial Intelligence and knowledge from human experts and existing software from NASA's COSMIC database. They devised a classification scheme for the software specifications, and a small set of generic software components that represent complexity and apply to large classes of programs. The specifications are converted to generic components by a set of rules and the generic components are input to a nonlinear sizing function which makes the final prediction. The system developed for this project predicted code sizes from the database with a bias factor of 1.06 and a fluctuation factor of 1.77, an accuracy similar to that of human experts but without their significant optimistic bias.

Predicting the recruitment of established regeneration into the sapling size class following partial cutting in the Acadian Forest Region: Using long-term observations to assess the performance of FVS-NE

Treesearch

David Ray; Chad Keyser; Robert Seymour; John Brissette

2008-01-01

Forest managers are increasingly called upon to provide long-term predictions of forest development. The dynamics of regeneration establishment, survival and subsequent recruitment of established seedlings to larger size classes is a critical component of these forecasts, yet remains a weak link in available models. To test the reliability of FVS-NE for simulating...

Integrated argument-based inquiry with multiple representation approach to promote scientific argumentation skill

NASA Astrophysics Data System (ADS)

Suminar, Iin; Muslim, Liliawati, Winny

2017-05-01

The purpose of this research was to identify student's written argument embedded in scientific inqury investigation and argumentation skill using integrated argument-based inquiry with multiple representation approach. This research was using quasi experimental method with the nonequivalent pretest-posttest control group design. Sample ot this research was 10th grade students at one of High School in Bandung using two classes, they were 26 students of experiment class and 26 students of control class. Experiment class using integrated argument-based inquiry with multiple representation approach, while control class using argument-based inquiry. This study was using argumentation worksheet and argumentation test. Argumentation worksheet encouraged students to formulate research questions, design experiment, observe experiment and explain the data as evidence, construct claim, warrant, embedded multiple modus representation and reflection. Argumentation testinclude problem which asks students to explain evidence, warrants, and backings support of each claim. The result of this research show experiment class students's argumentation skill performed better than control class students that of experiment class was 0.47 and control class was 0.31. The results of unequal variance t-test for independent means show that students'sargumentationskill of experiment class performed better significantly than students'sargumentationskill of control class.

Plant-mediated effects on extracellular enzyme activities in distinct soil aggregate size classes in field

NASA Astrophysics Data System (ADS)

Kumar, Amit; Dorodnikov, Maxim; Splettstößer, Thomas; Kuzyakov, Yakov; Pausch, Johanna

2017-04-01

Soil aggregation and microbial activities within the aggregates are important factors regulating soil carbon (C) turnover. A reliable and sensitive proxy for microbial activity is activity of extracellular enzymes (EEA). In the present study, effects of soil aggregates on EEA were investigated under three maize plant densities (Low, Normal, and High). Bulk soil was fractionated into three aggregate size classes (>2000 µm large macroaggregates; 2000-250 µm small macroaggregates; <250 µm microaggregates) by optimal-moisture sieving. Microbial biomass and EEA (β-1,4-glucosidase (BG), β-1,4-N-acetylglucosaminidase (NAG), L-leucine aminopeptidase (LAP) and acid phosphatase (acP)) catalyzing soil organic matter (SOM) decomposition were measured in rooted soil of maize and soil from bare fallow. Microbial biomass C (Cmic) decreased with decreasing aggregate size classes. Potential and specific EEA (per unit of Cmic) increased from macro- to microaggregates. In comparison with bare fallow soil, specific EEA of microaggregates in rooted soil was higher by up to 73%, 31%, 26%, and 92% for BG, NAG, acP and LAP, respectively. Moreover, high plant density decreased macroaggregates by 9% compared to bare fallow. Enhanced EEA in three aggregate size classes demonstrated activation of microorganisms by roots. Strong EEA in microaggregates can be explained by microaggregates' localization within the soil. Originally adhering to surfaces of macroaggregates, microaggregates were preferentially exposed to C substrates and nutrients, thereby promoting microbial activity.

Population biology and feeding habits of the nephropid lobster Metanephrops thomsoni (Bate, 1888) in the East China Sea.

PubMed

Choi, Jung Hwa; Kim, Jung Nyun; Kim, Mi Hyang; Chang, Dae Soo; Yoo, Joon Taek; Kim, Jin Koo

2008-07-01

Population biology and feeding habits of the nephropidlobsterMetanephrops thomsoni (Bate) was studied from a field survey sampled with bottom trawls in the East China Sea. The female/male ratio was 1.06:1. Three size-class groups were discriminated for both sexes, which may correspond to one to three year-old cohorts. The average stage fecundity was 471 in each brood. Larger than two-year-size-class females are multi broods during the breeding season. Gut analysis showed that this lobster is a common camivore and mainly consume crustaceans and fishes, regardless of sex and carapace length size.

Relating physico-chemical properties of frozen green peas (Pisum sativum L.) to sensory quality.

PubMed

Nleya, Kathleen M; Minnaar, Amanda; de Kock, Henriëtte L

2014-03-30

The acceptability of frozen green peas depends on their sensory quality. There is a need to relate physico-chemical parameters to sensory quality. In this research, six brands of frozen green peas representing product sold for retail and caterer's markets were purchased and subjected to descriptive sensory evaluation and physico-chemical analyses (including dry matter content, alcohol insoluble solids content, starch content, °Brix, residual peroxidase activity, size sorting, hardness using texture analysis and colour measurements) to assess and explain product quality. The sensory quality of frozen green peas, particularly texture properties, were well explained using physico-chemical methods of analysis notably alcohol insoluble solids, starch content, hardness and °Brix. Generally, retail class peas were of superior sensory quality to caterer's class peas although one caterer's brand was comparable to the retail brands. Retail class peas were sweeter, smaller, greener, more moist and more tender than the caterer's peas. Retail class peas also had higher °Brix, a(*) , hue and chroma values; lower starch, alcohol insoluble solids, dry matter content and hardness measured. The sensory quality of frozen green peas can be partially predicted by measuring physico-chemical parameters particularly °Brix and to a lesser extent hardness by texture analyser, alcohol insoluble solids, dry matter and starch content. © 2013 Society of Chemical Industry.

Accelerating the development of formal thinking in middle and high school students

NASA Astrophysics Data System (ADS)

Adey, Philip; Shayer, Michael

In an attempt to accelerate the development of formal operations in average young adolescents, intervention lessons relating to all formal schemata were designed in the context of school science courses. Over a period of two years, up to 30 intervention lessons were given by science teachers to their classes in eight schools. Boys who started the program aged 12+ showed a pre-posttest effect size on Piagetian tests of 0.89 SD compared with control classes. In terms of British norms for the development of operational thinking this was a mean change from the 51st to the 74th percentile. Neither the middle school students nor the 12+ girls showed greater gain than the controls. Gains were shown by girls in one 11+ class and in the two 11+ laboratory classes. In the laboratory school students given intervention lessons by the researchers maintained their gains over controls in formal operations at a delayed posttest one year after cessation of the program. There was no effect on tests of science achievement during the intervention. It was argued that the interventions needed to be accompanied by in-service training designed to enable teachers to change their teaching style in line with their students' increased operational thinking capacity.

75 FR 28077 - Small Business Size Standards: Waiver of the Nonmanufacturer Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-19

... class waiver of the Nonmanufacturer Rule for Improved Outer Tactical Vests and related accessories under... Class Waiver for Improved Outer Tactical Vests, PSC 8470, NAICS code 339113, Federal Register Notice...

[Plant signaling peptides. Cysteine-rich peptides].

PubMed

Ostrowski, Maciej; Kowalczyk, Stanisław

2015-01-01

Recent bioinformatic and genetic analyses of several model plant genomes have revealed the existence of a highly abundant group of signaling peptides that are defined as cysteine-rich peptides (CRPs). CRPs are usually in size between 50 and 90 amino acid residues, they are positively charged, and they contain 4-16 cysteine residues that are important for the correct conformational folding. Despite the structural differences among CRP classes, members from each class have striking similarities in their molecular properties and function. The present review presents the recent progress in research on signaling peptides from several families including: EPF/EPFL, SP11/SCR, PrsS, RALF, LURE, and some other peptides belonging to CRP group. There is convincing evidence indicating multiple roles for these CRPs as signaling molecules during the plant life cycle, ranging from stomata development and patterning, self-incompatibility, pollen tube growth and guidance, reproductive processes, and nodule formation.

Combining unique properties of dendrimers and magnetic nanoparticles towards cancer theranostics.

PubMed

Chandra, Sudeshna; Nigam, Saumya; Bahadur, Dhirendra

2014-01-01

Magnetic nanoparticles (MNPs) are a well explored class of nanomaterials, known for their high magnetization and biocompatibility thus finding their way in several biomedical applications viz., drug delivery, magnetic resonance imaging contrast agent, immunoassay, detoxification of biological fluids and cell separation, biosensing and hyperthermia. On other hand, dendrimers are a class of hyperbranched, mostly symmetrical polymers that originate from a central core with repetitive branching units, called monomers, thus forming a globular structure. Due to their structural properties and controlled size, dendrimers have emerged as an attractive material for biomedical applications particularly as carriers for therapeutic cargo. Of late, researchers have started attempting to combine the unique features of dendrimer chemistry with the versatile magnetic nanoparticles to provide a facile platform for enhanced therapeutics and biomedical applications. This review intends to present the advances made towards fabrication of dendrimer based magnetic nanoparticles with varied surface architecture and their contribution towards theranostics, particularly for cancer.

The utilization of the seven principles for good practices of full-time and adjunct faculty in teaching health & science in community colleges

NASA Astrophysics Data System (ADS)

Musaitif, Linda M.

Purpose. The purpose of this study was to determine the degree to which undergraduate full-time and adjunct faculty members in the health and science programs at community colleges in Southern California utilize the seven principles of good practice as measured by the Faculty Inventory of the Seven Principles for Good Practice in Undergraduate Education. A second purpose was to compare degree of utilization for gender and class size. Methodology. This is a quantitative study wherein there exists a systematic and mathematical assessment of data gathered through the use of a Likert scale survey to process and determine the mathematical model of the use of the principles by the target population of both full-time and adjunct faculty of health/science programs of community colleges in Southern California. Findings. Examination of the data revealed that both full-time and adjunct faculty members of Southern California community colleges perceive themselves a high degree of utilization of the seven principles of good practice. There was no statistically significant data to suggest a discrepancy between full-time and adjunct professors' perceptions among the utilization of the seven principles. Overall, male faculty members perceived themselves as utilizing the principles to a greater degree than female faculty. Data suggest that faculty with class size 60 or larger showed to utilize the seven principles more frequently than the professors with smaller class sizes. Conclusions. Full-time and adjunct professors of the health and sciences in Southern California community colleges perceive themselves as utilizing the seven principles of good practice to a high degree. Recommendations. This study suggests many recommendations for future research, including the degree to which negative economic factors such as budget cuts and demands affect the utilization of the seven principles. Also recommended is a study comparing students' perceptions of faculty's utilization of the seven principles of good practice in the classroom with faculty's self-perception.

Supply and Demand for Radiation Oncology in the United States: Updated Projections for 2015 to 2025

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Hubert Y.; Haffty, Bruce G.; Falit, Benjamin P.

Purpose: Prior studies have forecasted demand for radiation therapy to grow 10 times faster than the supply between 2010 and 2020. We updated these projections for 2015 to 2025 to determine whether this imbalance persists and to assess the accuracy of prior projections. Methods and Materials: The demand for radiation therapy between 2015 and 2025 was estimated by combining current radiation utilization rates determined by the Surveillance, Epidemiology, and End Results data with population projections provided by the US Census Bureau. The supply of radiation oncologists was forecast by using workforce demographics and full-time equivalent (FTE) status provided by themore » American Society for Radiation Oncology (ASTRO), current resident class sizes, and expected survival per life tables from the US Centers for Disease Control. Results: Between 2015 and 2025, the annual total number of patients receiving radiation therapy during their initial treatment course is expected to increase by 19%, from 490,000 to 580,000. Assuming a graduating resident class size of 200, the number of FTE physicians is expected to increase by 27%, from 3903 to 4965. In comparison with prior projections, the new projected demand for radiation therapy in 2020 dropped by 24,000 cases (a 4% relative decline). This decrease is attributable to an overall reduction in the use of radiation to treat cancer, from 28% of all newly diagnosed cancers in the prior projections down to 26% for the new projections. By contrast, the new projected supply of radiation oncologists in 2020 increased by 275 FTEs in comparison with the prior projection for 2020 (a 7% relative increase), attributable to rising residency class sizes. Conclusion: The supply of radiation oncologists is expected to grow more quickly than the demand for radiation therapy from 2015 to 2025. Further research is needed to determine whether this is an appropriate correction or will result in excess capacity.« less

A quantitative life history of endangered humpback chub that spawn in the Little Colorado River: variation in movement, growth, and survival

USGS Publications Warehouse

Yackulic, Charles B.; Yard, Michael D.; Korman, Josh; Van Haverbeke, David R.

2014-01-01

While the ecology and evolution of partial migratory systems (defined broadly to include skip spawning) have been well studied, we are only beginning to understand how partial migratory populations are responding to ongoing environmental change. Environmental change can lead to differences in the fitness of residents and migrants, which could eventually lead to changes in the frequency of the strategies in the overall population. Here, we address questions concerning the life history of the endangered Gila cypha (humpback chub) in the regulated Colorado River and the unregulated tributary and primary spawning area, the Little Colorado River. We develop eight multistate models for the population based on three movement hypotheses, in which states are defined in terms of fish size classes and river locations. We fit these models to mark–recapture data collected in 2009–2012. We compare survival and growth estimates between the Colorado River and Little Colorado River and calculate abundances for all size classes. The best model supports the hypotheses that larger adults spawn more frequently than smaller adults, that there are residents in the spawning grounds, and that juveniles move out of the Little Colorado River in large numbers during the monsoon season (July–September). Monthly survival rates for G. cypha in the Colorado River are higher than in the Little Colorado River in all size classes; however, growth is slower. While the hypothetical life histories of life-long residents in the Little Colorado River and partial migrants spending most of its time in the Colorado River are very different, they lead to roughly similar fitness expectations when we used expected number of spawns as a proxy. However, more research is needed because our study period covers a period of years when conditions in the Colorado River for G. cypha are likely to have been better than has been typical over the last few decades.

Purification and Characterization of Enzymes from Yeast: An Extended Undergraduate Laboratory Sequence for Large Classes

ERIC Educational Resources Information Center

Johanson, Kelly E.; Watt, Terry J.; McIntyre, Neil R.; Thompson, Marleesa

2013-01-01

Providing a project-based experience in an undergraduate biochemistry laboratory class can be complex with large class sizes and limited resources. We have designed a 6-week curriculum during which students purify and characterize the enzymes invertase and phosphatase from bakers yeast. Purification is performed in two stages via ethanol…

Student Response Systems and Facilitating the Large Lecture Basic Communication Course: Assessing Engagement and Learning

ERIC Educational Resources Information Center

Denker, Katherine J.

2013-01-01

Instructors of large lecture classes face a variety of challenges, including student engagement and participation. With budget cuts and increasing class sizes, more schools may turn to large lecture/lab formats for the basic communication course (Stanley & Porter, 2002); instructors must understand how these classes engage students. One viable…

Evaluating the Benefits of Providing Archived Online Lectures to In-Class Math Students

ERIC Educational Resources Information Center

Cascaval, Radu C.; Fogler, Kethera A.; Abrams, Gene D.; Durham, Robert L.

2008-01-01

The present study examines the impact of a novel online video lecture archiving system on in-class students enrolled in traditional math courses at a mid-sized, primarily undergraduate, university in the West. The archiving system allows in-class students web access to complete video recordings of the actual classroom lectures, and sometimes of…

Taphonomic Analysis of Rodentia and Lagomorpha Bone Gnawing Based Upon Incisor Size.

PubMed

Pokines, James T; Sussman, Rachel; Gough, Megan; Ralston, Claira; McLeod, Elizabeth; Brun, Karen; Kearns, Aisling; Moore, Tara L

2017-01-01

Rodent and lagomorph species have a worldwide distribution and have the potential to alter remains from forensic cases by gnawing soft tissue and bones and through dispersal. The present research compiled metric data on the incisors widths of all rodent and lagomorph species whose ranges include Massachusetts, U.S.A., to compare their sizes to gnawing damage found on 17 cases of human remains from the Office of the Chief Medical Examiner, Boston, MA. Data on gnawing maximum striation widths also were collected from live laboratory, zoo, and wild specimens. Gnawing damage on the forensic cases could be attributed only to a particular size class of rodent or lagomorph, and identification to a particular species based on gnawing damage alone may be possible only in relatively rare cases. Multiple species examined here have broad distribution ranges, so their taphonomic alterations may impact bones from forensic cases throughout large portions of North America. © 2016 American Academy of Forensic Sciences.

Scaling, clustering and avalanches for steel beads in an external magnetic field

NASA Astrophysics Data System (ADS)

Marquinez, Alyse; Thvedt, Ingrid; Lehman, S. Y.; Jacobs, D. T.

2011-03-01

We investigated avalanches using uniform 3mm steel spheres (``beads'') dropped onto a conical bead pile within a uniform magnetic field. The bead pile is built by pouring beads onto a circular base where the bottom layer of beads had been glued randomly. Beads are then individually dropped from a fixed height after which the pile is massed. This process is repeated for thousands of bead drops. By measuring the number of avalanches of a given size that occurred during the experiment, the resulting avalanche size distribution was compared to a power law description as predicted by self-organized criticality. As the magnetic field intensity increased, the beads clustered to give a larger angle of repose and we measured the change in the avalanche size distribution. The moments of the distribution give a sensitive test of mean-field theory as the universality class for these bead piles. We acknowledge support from Research Corporation and NSF-REU grant DMR 0649112.

Coarsening dynamics in condensing zero-range processes and size-biased birth death chains

NASA Astrophysics Data System (ADS)

Jatuviriyapornchai, Watthanan; Grosskinsky, Stefan

2016-05-01

Zero-range processes with decreasing jump rates are well known to exhibit a condensation transition under certain conditions on the jump rates, and the dynamics of this transition continues to be a subject of current research interest. Starting from homogeneous initial conditions, the time evolution of the condensed phase exhibits an interesting coarsening phenomenon of mass transport between cluster sites characterized by a power law. We revisit the approach in Godrèche (2003 J. Phys. A: Math. Gen. 36 6313) to derive effective single site dynamics which form a nonlinear birth death chain describing the coarsening behavior. We extend these results to a larger class of parameter values, and introduce a size-biased version of the single site process, which provides an effective tool to analyze the dynamics of the condensed phase without finite size effects and is the main novelty of this paper. Our results are based on a few heuristic assumptions and exact computations, and are corroborated by detailed simulation data.

Development of population structure and spatial distribution patterns of a restored forest during 17-year succession (1993-2010) in Pingshuo opencast mine spoil, China.

PubMed

Zhao, Zhongqiu; Wang, Lianhua; Bai, Zhongke; Pan, Ziguan; Wang, Yun

2015-07-01

Afforestation of native tree species is often recommended for ecological restoration in mining areas, but the understanding of the ecological processes of restored vegetation is quite limited. In order to provide insight of the ecological processes of restored vegetation, in this study, we investigate the development of the population structure and spatial distribution patterns of restored Robinia pseudoacacia (ROPS) and Pinus tabuliformis (PITA) mixed forests during the 17 years of the mine spoil period of the Pingshuo opencast mine, Shanxi Province, China. After a 17-year succession, apart from the two planted species, Ulmus pumila (ULPU), as an invasive species, settled in the plot along with a large number of small diameter at breast height (DBH) size. In total, there are 10,062 living individual plants, much more than that at the plantation (5105), and ROPS had become the dominant species with a section area with a breast height of 9.40 m(2) hm(-2) and a mean DBH of 6.72 cm, much higher than both PITA and ULPU. The DBH size classes of all the total species showed inverted J-shaped distributions, which may have been a result of the large number of small regenerated ULPU trees. The DBH size classes of both ROPS and PITA showed peak-type structures with individuals mainly gathering in the moderate DBH size class, indicating a relatively healthy DBH size class structure. Meanwhile, invasive ULPU were distributed in a clear L shape, concentrating on the small DBH size class, indicating a relatively low survival rate for adult trees. Both ROPS and PITA species survival in the plantation showed uniform and aggregated distribution at small scales and random with scales increasing. ULPU showed a strong aggregation at small scales as well as random with scales increasing. Both the population structure and spatial distribution indicated that ROPS dominates and will continue to dominate the community in the future succession, which should be continuously monitored.

Variation in size frequency distribution of coral populations under different fishing pressures in two contrasting locations in the Indian Ocean.

PubMed

Grimsditch, G; Pisapia, C; Huck, M; Karisa, J; Obura, D; Sweet, M

2017-10-01

This study aimed to assess how the size-frequency distributions of coral genera varied between reefs under different fishing pressures in two contrasting Indian Ocean locations (the Maldives and East Africa). Using generalized linear mixed models, we were able to demonstrate that complex interactions occurred between coral genera, coral size class and fishing pressure. In both locations, we found Acropora coral species to be more abundant in non-fished compared to fished sites (a pattern which was consistent for nearly all the assessed size classes). Coral genera classified as 'stress tolerant' showed a contrasting pattern i.e. were higher in abundance in fished compared to non-fished sites. Site specific variations were also observed. For example, Maldivian reefs exhibited a significantly higher abundance in all size classes of 'competitive' corals compared to East Africa. This possibly indicates that East African reefs have already been subjected to higher levels of stress and are therefore less suitable environments for 'competitive' corals. This study also highlights the potential structure and composition of reefs under future degradation scenarios, for example with a loss of Acropora corals and an increase in dominance of 'stress tolerant' and 'generalist' coral genera. Copyright © 2017. Published by Elsevier Ltd.

Size of nesting female Broad-snouted Caimans (Caiman latirostris Daudin 1802).

PubMed

Leiva, P M L; Simoncini, M S; Portelinha, T C G; Larriera, A; Piña, C I

2018-03-12

The southern distribution of the Broad-snouted Caiman (Caiman latirostris Daudin 1802) in Argentina occurs in Santa Fe Province, where its population has been under management by "Proyecto Yacaré" since 1990. From 1997 to 2016, we captured 77 nesting female Broad-snouted Caimans in Santa Fe Province. Our results suggest that previously defined size classes for Broad-snouted Caiman do not adequately describe the reproductively mature female segment of the population. Here we propose to change size ranges for general size classes for Broad-snouted Caiman. In addition, we have observed that reintroduced reproductive females by Proyecto Yacaré represent about 32% of captured females. These results indicate that reintroduced females by the management program are surviving and reproducing in the wild at least up to 20 years.

Support Vector Data Description Model to Map Specific Land Cover with Optimal Parameters Determined from a Window-Based Validation Set.

PubMed

Zhang, Jinshui; Yuan, Zhoumiqi; Shuai, Guanyuan; Pan, Yaozhong; Zhu, Xiufang

2017-04-26

This paper developed an approach, the window-based validation set for support vector data description (WVS-SVDD), to determine optimal parameters for support vector data description (SVDD) model to map specific land cover by integrating training and window-based validation sets. Compared to the conventional approach where the validation set included target and outlier pixels selected visually and randomly, the validation set derived from WVS-SVDD constructed a tightened hypersphere because of the compact constraint by the outlier pixels which were located neighboring to the target class in the spectral feature space. The overall accuracies for wheat and bare land achieved were as high as 89.25% and 83.65%, respectively. However, target class was underestimated because the validation set covers only a small fraction of the heterogeneous spectra of the target class. The different window sizes were then tested to acquire more wheat pixels for validation set. The results showed that classification accuracy increased with the increasing window size and the overall accuracies were higher than 88% at all window size scales. Moreover, WVS-SVDD showed much less sensitivity to the untrained classes than the multi-class support vector machine (SVM) method. Therefore, the developed method showed its merits using the optimal parameters, tradeoff coefficient ( C ) and kernel width ( s ), in mapping homogeneous specific land cover.

Using Facebook to Supplement Participant Pools for Class Research Projects: Should We Like It?

ERIC Educational Resources Information Center

Sciutto, Mark J.

2015-01-01

In-class research projects are a valuable way of providing research experience for undergraduate students in psychology. This article evaluates the use of online social networks to supplement sample recruitment for in-class research projects. Specifically, this article presents a systematic analysis of seven student research projects that…

Biochemical distributions (amino acids, neutral sugars, and lignin phenols) among size-classes of modern marine sediments from the Washington coast

NASA Astrophysics Data System (ADS)

Keil, Richard G.; Tsamakis, Elizabeth; Giddings, J. Calvin; Hedges, John I.

1998-04-01

In order to examine relationships of organic matter source, composition, and diagenesis with particle size and mineralogy in modern marine depositional regimes, sediments from the continental shelf and slope along the Northwest Pacific rim (Washington coast, USA) were sorted into hydrodynamic size fractions (sand: >250, 63-250 μm; silt: 35-63, 17-35, 8-17, 3-8 μm; and clay-sized: 1-3, 0.5-1, <0.5 μm). The size fractions were then density fractionated to separate distinct organic debris from mineral-associated organic matter, and the various separates were analyzed for their amino acid, aldose, and lignin compositions. The composition of organic matter in the separates changes markedly as a function of particle size and density. Large compositional differences were observed between the clay-sized fractions (dominated mineralogically by smectites), the sand-sized mineral-associated isolates (quartz-rich), and floated coarse organic matter (dominated by vascular plant debris). Organic matter intimately associated with the clay-sized fractions shows the most extensive diagenetic alteration, as reflected in high abundances of nonprotein amino acids (especially β-alanine), elevated lignin phenol acid/aldehyde ratios, and high relative concentrations of the deoxyhexoses fucose and rhamnose. Organic matter in the silt fractions, though degraded, is not as diagenetically altered as in the clay fractions. Enrichment of pollen grains in the silt-size material is reflected by high cinnamic acid to ferulic acid lignin phenol ratios. The highest pollen biochemical signal is observed in the silt fractions of the deepest station (1835 m), where pollen abundances are also highest. Organic matter tightly bound in the silt and sand-sized fractions are enriched in aldoses and show indications of enhanced microbial biomass as reflected by high weight percentages of ribose. Distinct organic debris was composed of relatively unaltered vascular plant remains as reflected by high lignin phenol yields and low acid/aldehyde ratios. Clay-size fractions are enriched in nitrogenous components, as reflected by elevated yields of total and basic amino acids (especially lysine). Silt- and sand-size fractions rich in quartz and albite show slightly higher yields of neutral amino acids. Consistent trends across all size classes and among the different depositional settings illustrates that only a small portion of the organic matter is present as distinct organic debris (e.g. pollen, vascular plant tissues, etc.), but that this debris can be isolated in specific size classes. The data for surface-associated organic matter are consistent with, but not conclusive of, selective partitioning of some organic matter to specific mineral surfaces. The dominant size class-specific trends in organic matter composition are due to changes in both source and diagenetic alteration.

Multilevel latent class casemix modelling: a novel approach to accommodate patient casemix

PubMed Central

2011-01-01

Background Using routinely collected patient data we explore the utility of multilevel latent class (MLLC) models to adjust for patient casemix and rank Trust performance. We contrast this with ranks derived from Trust standardised mortality ratios (SMRs). Methods Patients with colorectal cancer diagnosed between 1998 and 2004 and resident in Northern and Yorkshire regions were identified from the cancer registry database (n = 24,640). Patient age, sex, stage-at-diagnosis (Dukes), and Trust of diagnosis/treatment were extracted. Socioeconomic background was derived using the Townsend Index. Outcome was survival at 3 years after diagnosis. MLLC-modelled and SMR-generated Trust ranks were compared. Results Patients were assigned to two classes of similar size: one with reasonable prognosis (63.0% died within 3 years), and one with better prognosis (39.3% died within 3 years). In patient class one, all patients diagnosed at stage B or C died within 3 years; in patient class two, all patients diagnosed at stage A, B or C survived. Trusts were assigned two classes with 51.3% and 53.2% of patients respectively dying within 3 years. Differences in the ranked Trust performance between the MLLC model and SMRs were all within estimated 95% CIs. Conclusions A novel approach to casemix adjustment is illustrated, ranking Trust performance whilst facilitating the evaluation of factors associated with the patient journey (e.g. treatments) and factors associated with the processes of healthcare delivery (e.g. delays). Further research can demonstrate the value of modelling patient pathways and evaluating healthcare processes across provider institutions. PMID:21362172

Science Illiteracy: Breaking the Cycle

NASA Astrophysics Data System (ADS)

Lebofsky, L. A.; Lebofsky, N. R.

2003-12-01

At the University of Arizona, as at many state universities and colleges, the introductory science classes for non-science majors may be the only science classes that future K--8 teachers will take. The design of the UA's General Education program requires all future non-science certified teachers to take the General Education science classes. These classes are therefore an ideal venue for the training of the state's future teachers. Many students, often including future teachers, are ill-prepared for college, i.e., they lack basic science content knowledge, basic mathematics skills, and reading and writing skills. They also lack basic critical thinking skills and study skills. It is within this context that our future teachers are trained. How do we break the cycle of science illiteracy? There is no simple solution, and certainly not a one-size-fits-all panacea that complements every professor's style of instruction. However, there are several programs at the University of Arizona, and also principles that I apply in my own classes, that may be adaptable in other classrooms. Assessment of K--12 students' learning supports the use of inquiry-based science instruction. This approach can be incorporated in college classes. Modeling proven and productive teaching methods for the future teachers provides far more than ``just the facts,'' and all students gain from the inquiry approach. Providing authentic research opportunities employs an inquiry-based approach. Reading (outside the textbook) and writing provide feedback to students with poor writing and critical thinking skills. Using peer tutors and an instant messaging hot line gives experience to the tutors and offers "comfortable" assistance to students.

Microstructural indicators of convection: insights from the Little Minch Sill Complex, Scotland

NASA Astrophysics Data System (ADS)

Nicoli, Gautier; Holness, Marian; Neufeld, Jerome; Farr, Robert

2017-04-01

The fluid dynamic behaviour of crystal-bearing magmas is a key parameter to understand the formation of magmatic bodies. There are two opposite views on the subject: Some argue that solidification in intrusive bodies is affected by convection whereas others claim solidification happens in a static environment. A consensus on the question may be reached by carefully studying the grain size distribution in the settled accumulations of cargo crystals. In the absence of significant crystal growth or particle coarsening by agglomeration, settling of a polydisperse crystal load will always result in a fining-upwards sequence in static magmas as well as in convecting environments. If we assume the particle concentration is always sufficiently low to prevent hindered settling, gravitational settling in a static magma leads to the settling of individual crystals at a constant rate determined by their Stokes' velocity. Each size class is deposited at a constant rate, until all the grains of that size class have fallen out of suspension, leading to a well-stratified sequence and the complete disappearance of progressively smaller size classes upwards in the accumulation. In contrast, in a vigorously convecting magma crystals settle when they enter the stagnant basal boundary layer. In a system containing a polydisperse crystal population most of the bigger particles are removed rapidly from the bulk magma, leading to the creation of a fining-upwards sequence on the floor. However, in detail the structure of this fining-upwards sequence is critically different from that created by settling from a stagnant magma, with the gradual phasing out of each size class instead of the abrupt termination of size classes seen in static systems. This provides us with the opportunity to distinguish between settling from static or convecting magma using the spatial variation of grain size in settled accumulations. We focus on the Little Minch Sill Complex in Scotland, which formed from olivine-phyric magma and is characterised by both composite and single-injection bodies with significant accumulation of olivine on their lower margins. Comparison of the fining-upwards sequences in the picrodolerite/crinanite unit of the composite Shiant Isles Main Sill,and related single-injection sills on the Trotternish Peninsula, Skye, illustrate the ability of this method to distinguish between convecting and non-convecting magma bodies.

The size-reactivity continuum of major bioelements in the ocean.

PubMed

Benner, Ronald; Amon, Rainer M W

2015-01-01

Most of the carbon fixed in primary production is rapidly cycled and remineralized, leaving behind various forms of organic carbon that contribute to a vast reservoir of nonliving organic matter in seawater. Most of this carbon resides in dissolved molecules of varying bioavailability and reactivity, and aspects of the cycling of this carbon remain an enigma. The size-reactivity continuum model provides a conceptual framework for understanding the mechanisms governing the formation and mineralization of this carbon. In the seawater bioassay experiments that served as the original basis for this model, investigators observed that larger size classes of organic matter were more bioavailable and more rapidly remineralized by microbes than were smaller size classes. Studies of the chemical composition and radiocarbon content of marine organic matter have further indicated that the complexity and age of organic matter increase with decreasing molecular size. Biodegradation processes appear to shape the size distribution of organic matter and the nature of the small dissolved molecules that persist in the ocean.

Tooth size discrepancies in Class II division 1 and Class III malocclusion requiring surgical-orthodontic or orthodontic treatment.

PubMed

McSwiney, Timothy P; Millett, Declan T; McIntyre, Grant T; Barry, Mark K; Cronin, Michael S

2014-06-01

To compare mean anterior (AR) and mean overall (OR) tooth size ratios, prevalence of clinically significant tooth size discrepancies (TSDs) and correlation between AR and OR in subjects with Class II division 1 and Class III malocclusion treated by surgical-orthodontic or orthodontic means. Retrospective, cross-sectional. State-funded and private clinics. From pre-treatment cohorts of 770 surgical and 610 non-surgical subjects, Class II division 1 and Class III malocclusion groups were identified with 60 surgical and 60 non-surgical subjects, comprising 30 males and 30 females, in each. AR and OR were calculated by landmarking digital models. Differences in AR and OR and their relationship were analysed using two-way analysis of variance (ANOVA) and a correlation coefficient, respectively. The proportions of the surgical and non-surgical groups with a TSD were assessed using logistic regression. Intra-examiner reproducibility involved re-landmarking 30 randomly selected image sets and differences in ARs and ORs were compared using a paired t-test. Random error was assessed using the intraclass correlation coefficient (ICC). Analyses were performed using SAS (SAS Institute Inc., Cary, NC, USA) at the 5% level of significance. There were no statistically significant differences associated with the measurement of either the mean AR (P = 0·913) or the mean OR (P = 0·874). ICC values were very high (AR = 0·95; OR = 0·90). Differences existed between both Class II and Class III surgical (AR: P<0·001; OR: P<0·001) and non-surgical groups (AR: P = 0·012; OR: P = 0·003). The AR and OR relationship was strong (correlation coefficient = 0·72). The highest percentage of clinically significant TSDs was seen in the AR of both Class II and Class III surgical groups (23·3%). In the cohort examined: AR and OR differed significantly for malocclusion groups. The prevalence of clinically significant TSDs did not differ significantly between surgical and non-surgical groups although the highest percentage of clinically significant TSDs was recorded for AR in Class II and Class III surgical cases. AR and OR were closely related. © 2014 British Orthodontic Society.

Naming, the Formation of Stimulus Classes, and Applied Behavior Analysis.

ERIC Educational Resources Information Center

Stromer, Robert; And Others

1996-01-01

This review of research discusses how children with autism may acquire equivalence classes after learning to supply a common oral name to each stimulus in a potential class. A proposed methodology for researching referent naming and class formation, analysis of stimulus classes, and generalization is offered. (CR)

Collection of small-size diffraction radiation oscillators

NASA Astrophysics Data System (ADS)

Shestopalov, Victor P.; Skrynnik, Boris K.

1995-10-01

The systematic research and engineering efforts for new class of vacuum tube devices such as diffraction radiation generators are in progress in the IRE of the National Academy of Sciences of Ukraine. For its operation DRG is based on excitation of open resonator (OR) by the Smith-Pursell radiation initiated when electron flow is rectinearly moving near diffracted grating (DG) arranged on one of the OR mirrors. By now a collection of small-sized highly stable through all mm band DRG, packetized in optimum magnet systems with air clearance of 32 mm is available. The supply power is less then 500 W. The magnetic field for accompanying of electron flow is 0,4-0,7 T. The mass of optimum magnet syustem of rare- earth elements is about 2-8 kg. The device is cooling by the water system.

Literacy Gaps by Educational Attainment: A Cross-National Analysis.

PubMed

Park, Hyunjoon; Kyei, Pearl

2011-03-01

Existing cross-national research on educational attainment does not fully address whether the same level of educational attainment generates the same level of literacy skills in different countries. We analyze literacy skills data for young adults from 19 countries in the 1994-1998 International Adult Literacy Survey and find that in all countries, individuals with a higher level of educational attainment tend to have greater literacy skills. However, there is substantial variation across countries in the size of literacy gaps by levels of educational attainment. In particular, young adults in the United States show the largest literacy gaps. Using two-level hierarchical linear models, we find that cross-national differences in the literacy gap between more- and less-educated individuals are systematically linked to the degree of between-school inequality in school resources (instructional materials, class size, teachers' experience and certification).

Universality in a Neutral Evolution Model

NASA Astrophysics Data System (ADS)

King, Dawn; Scott, Adam; Maric, Nevena; Bahar, Sonya

2013-03-01

Agent-based models are ideal for investigating the complex problems of biodiversity and speciation because they allow for complex interactions between individuals and between individuals and the environment. Presented here is a ``null'' model that investigates three mating types - assortative, bacterial, and random - in phenotype space, as a function of the percentage of random death δ. Previous work has shown phase transition behavior in an assortative mating model with variable fitness landscapes as the maximum mutation size (μ) was varied (Dees and Bahar, 2010). Similarly, this behavior was recently presented in the work of Scott et al. (submitted), on a completely neutral landscape, for bacterial-like fission as well as for assortative mating. Here, in order to achieve an appropriate ``null'' hypothesis, the random death process was changed so each individual, in each generation, has the same probability of death. Results show a continuous nonequilibrium phase transition for the order parameters of the population size and the number of clusters (analogue of species) as δ is varied for three different mutation sizes of the system. The system shows increasing robustness as μ increases. Universality classes and percolation properties of this system are also explored. This research was supported by funding from: University of Missouri Research Board and James S. McDonnell Foundation

Effectiveness of discovery learning model on mathematical problem solving

NASA Astrophysics Data System (ADS)

Herdiana, Yunita; Wahyudin, Sispiyati, Ririn

2017-08-01

This research is aimed to describe the effectiveness of discovery learning model on mathematical problem solving. This research investigate the students' problem solving competency before and after learned by using discovery learning model. The population used in this research was student in grade VII in one of junior high school in West Bandung Regency. From nine classes, class VII B were randomly selected as the sample of experiment class, and class VII C as control class, which consist of 35 students every class. The method in this research was quasi experiment. The instrument in this research is pre-test, worksheet and post-test about problem solving of mathematics. Based on the research, it can be conclude that the qualification of problem solving competency of students who gets discovery learning model on level 80%, including in medium category and it show that discovery learning model effective to improve mathematical problem solving.

Determining the Population Size of Pond Phytoplankton.

ERIC Educational Resources Information Center

Hummer, Paul J.

1980-01-01

Discusses methods for determining the population size of pond phytoplankton, including water sampling techniques, laboratory analysis of samples, and additional studies worthy of investigation in class or as individual projects. (CS)

Population structure, density and food sources of Terebralia palustris (Potamididae: Gastropoda) in a low intertidal Avicennia marina mangrove stand (Inhaca Island, Mozambique)

NASA Astrophysics Data System (ADS)

Penha-Lopes, Gil; Bouillon, Steven; Mangion, Perrine; Macia, Adriano; Paula, José

2009-09-01

Population structure and distribution of Terebralia palustris were compared with the environmental parameters within microhabitats in a monospecific stand of Avicennia marina in southern Mozambique. Stable carbon and nitrogen isotope analyses of T. palustris and potential food sources (leaves, pneumatophore epiphytes, and surface sediments) were examined to establish the feeding preferences of T. palustris. Stable isotope signatures of individuals of different size classes and from different microhabitats were compared with local food sources. Samples of surface sediments 2.5-10 m apart showed some variation (-21.2‰ to -23.0‰) in δ13C, probably due to different contributions from seagrasses, microalgae and mangrove leaves, while δ15N values varied between 8.7‰ and 15.8‰, indicating that there is a very high variability within a small-scale microcosm. Stable isotope signatures differed significantly between the T. palustris size classes and between individuals of the same size class, collected in different microhabitats. Results also suggested that smaller individuals feed on sediment, selecting mainly benthic microalgae, while larger individuals feed on sediment, epiphytes and mangrove leaves. Correlations were found between environmental parameters and gastropod population structure and distribution vs. the feeding preferences of individuals of different size classes and in different microhabitats. While organic content and the abundance of leaves were parameters that correlated best with the total density of gastropods (>85%), the abundance of pneumatophores and leaves, as well as grain size, correlated better with the gastropod size distribution (>65%). Young individuals (height < 3 cm) occur predominantly in microhabitats characterized by a low density of leaf litter and pneumatophores, reduced organic matter and larger grain size, these being characteristic of lower intertidal open areas that favour benthic microalgal growth. With increasing shell height, T. palustris individuals start occupying microhabitats nearer the mangrove trees characterized by large densities of pneumatophores and litter, as well as sediments of smaller grain size, leading to higher organic matter availability in the sediment.

Large-scale changes in bloater growth and condition in Lake Huron

USGS Publications Warehouse

Prichard, Carson G.; Roseman, Edward F.; Keeler, Kevin M.; O'Brien, Timothy P.; Riley, Stephen C.

2016-01-01

Native Bloaters Coregonus hoyi have exhibited multiple strong year-classes since 2005 and now are the most abundant benthopelagic offshore prey fish in Lake Huron, following the crash of nonnative AlewivesAlosa pseudoharengus and substantial declines in nonnative Rainbow Smelt Osmerus mordax. Despite recent recoveries in Bloater abundance, marketable-size (>229 mm) Bloaters remain scarce. We used annual survey data to assess temporal and spatial dynamics of Bloater body condition and lengths at age in the main basin of Lake Huron from 1973 to 2014. Basinwide lengths at age were modeled by cohort for the 1973–2003 year-classes using a von Bertalanffy growth model with time-varying Brody growth coefficient (k) and asymptotic length () parameters. Median Bloater weights at selected lengths were estimated to assess changes in condition by modeling weight–length relations with an allometric growth model that allowed growth parameters to vary spatially and temporally. Estimated Bloater lengths at age declined 14–24% among ages 4–8 for all year-classes between 1973 and 2004. Estimates of  declined from a peak of 394 mm (1973 year-class) to a minimum of 238 mm (1998 year-class). Observed mean lengths at age in 2014 were at all-time lows, suggesting that year-classes comprising the current Bloater population would have to follow growth trajectories unlike those characterizing the 1973–2003 year-classes to attain marketable size. Furthermore, estimated weights of 250-mm Bloaters (i.e., a large, commercially valuable size-class) declined 17% among all regions from 1976 to 2007. Decreases in body condition of large Bloaters are associated with lower lipid content and may be linked to marked declines in abundance of the amphipodsDiporeia spp. in Lake Huron. We hypothesize that since at least 1976, large Bloaters have become more negatively buoyant and may have incurred an increasingly greater metabolic cost performing diel vertical migrations to prey upon the opossum shrimp Mysis diluviana and zooplankton.

A National Study Assessing the Teaching and Learning of Introductory Astronomy; Part I: The Effect of Interactive Instruction

NASA Astrophysics Data System (ADS)

Rudolph, Alexander; Prather, E. E.; Brissenden, G.; Schlingman, W. M.; CATS

2009-01-01

We present the results of a national study on the teaching and learning of astronomy taught in general education, non-science major, introductory astronomy courses (Astro 101). Nearly 4000 students enrolled in 69 sections of Astro 101 taught at 30 institutions around the United States completed (pre- and post-instruction) the Light and Spectroscopy Concept Inventory (LSCI) from Fall 2006 to Fall 2007. The classes varied in size from very small (N<10) to large (N 180) and were from all types of institutions, including both 2-year and 4-year colleges and universities. To study how the instruction in different classrooms affected student learning, we developed and administered an Interactivity Assessment Instrument (IAI). This short survey, completed by instructors, allowed us to estimate the fraction of total classroom time that was dedicated to the use of interactive learning strategies. Pre-instruction LSCI scores were clustered around 25% (24±2%), independent of class size and institution type; however, the normalized gains for these classes varied from about (-)0.07-0.50. These two results suggest that the differences in gain were due to instruction in the classroom, not the size of class or type of institution. Interactivity Assessment Scores (IAS's) ranged from 0%-50%, showing that our IAI was able to distinguish between classes with higher and lower levels of interactive instruction. A comparison of class-averaged gain score to IAS showed that higher interactivity classes (IAS > 25%) were the only instructional environments capable of reaching the highest gains ( > 0.30). However, the range of gains seen for the higher interactivity classes was quite wide, suggesting that the use of interactive learning strategies is not sufficient by itself to achieve high student gains. We acknowledge the NSF for funding under Award No. 0715517, a CCLI Phase III Grant for the Collaboration of Astronomy Teaching Scholars (CATS) Program.

Teething Problems in the Academy: Negotiating the Transition to Large-Class Teaching in the Discipline of History

ERIC Educational Resources Information Center

Keirle, Philip A.; Morgan, Ruth A.

2011-01-01

In this paper we provide a template for transitioning from tutorial to larger-class teaching environments in the discipline of history. We commence by recognising a number of recent trends in tertiary education in Australian universities that have made this transition to larger class sizes an imperative for many academics: increased student…

Financial implications of increasing medical school class size: does tuition cover cost?

PubMed

Schieffler, Danny A; Azevedo, Benjamin M; Culbertson, Richard A; Kahn, Marc J

2012-01-01

In 2006, the Association of American Medical Colleges (AAMC) issued a recommendation that medical schools increase the supply of physicians by 30% to meet the patient needs of the new millennium. To provide financial analysis of the cost of increasing class size. To determine the financial consequences of increasing medical student enrollment and in the absence of nationally published cost data for medical schools, adjusted secondary revenue data was analyzed using AAMC and Liaison Committee on Medical Education (LCME) financial data from 2009. Linear regression analysis was used to determine average fixed costs and variable cost per student in USD. In USD, $62,877 represents the best point estimate of the annual variable cost of educating a medical student. Comparing this cost to current tuitions and fees of LCME-accredited medical schools suggests that revenues other than tuition are needed to cover increases in class size. Tuition and fees revenue from increasing enrollment will not increase overall revenue to medical schools.

Effects of Soybean Seed Size on Weed Competition

USDA-ARS?s Scientific Manuscript database

Organic soybean producers must rely on various, nonherbicidal tactics for weed management. Increased soybean seed size may be one method to increase the competitiveness of the soybean canopy. Soybean varieties Hutcheson, NC-Roy, and NC-Raleigh were separated into four or five seed size classes. Seed...

A study on the impact of prioritising emergency department arrivals on the patient waiting time.

PubMed

Van Bockstal, Ellen; Maenhout, Broos

2018-05-03

In the past decade, the crowding of the emergency department has gained considerable attention of researchers as the number of medical service providers is typically insufficient to fulfil the demand for emergency care. In this paper, we solve the stochastic emergency department workforce planning problem and consider the planning of nurses and physicians simultaneously for a real-life case study in Belgium. We study the patient arrival pattern of the emergency department in depth and consider different patient acuity classes by disaggregating the arrival pattern. We determine the personnel staffing requirements and the design of the shifts based on the patient arrival rates per acuity class such that the resource staffing cost and the weighted patient waiting time are minimised. In order to solve this multi-objective optimisation problem, we construct a Pareto set of optimal solutions via the -constraints method. For a particular staffing composition, the proposed model minimises the patient waiting time subject to upper bounds on the staffing size using the Sample Average Approximation Method. In our computational experiments, we discern the impact of prioritising the emergency department arrivals. Triaging results in lower patient waiting times for higher priority acuity classes and to a higher waiting time for the lowest priority class, which does not require immediate care. Moreover, we perform a sensitivity analysis to verify the impact of the arrival and service pattern characteristics, the prioritisation weights between different acuity classes and the incorporated shift flexibility in the model.

Negotiating the Paris Agreement with the C-Learn Climate Simulator in an Interdisciplinary Undergraduate Climate Change Course

NASA Astrophysics Data System (ADS)

Straub, K. H.

2016-12-01

I teach an interdisciplinary course on modern climate change that attracts students from a variety of academic backgrounds. The class size is typically 20-25 students. The final exercise of the semester is an in-class simulation of the Paris Agreement negotiations, which integrates all of the topics the students have studied throughout the semester (science, politics, skeptic arguments, ethics, economics, etc.). For this exercise, we use the free online C-Learn climate simulator (https://www.climateinteractive.org/tools/c-learn/), but with several modifications from the suggested negotiation methodology. All but two students were assigned an individual country to represent within the larger groups "Developed," (e.g., US, EU, Australia), "Developing A" (e.g., China, India, Indonesia), and "Developing B" (e.g., Maldives, Haiti, Botswana). The remaining two students were assigned the roles of "Exxon Mobil" and "Greenpeace," to represent external lobbyists. Prior to the in-class negotiation, students completed an assignment on their individual role that required them to research their country's actual INDC and the projected impacts of a 2 degree C rise in average global temperature, as well as create "behavior rules" for their country to follow during the simulation. Lobbyists were given modified assignments. To make the simulation more complex and realistic, I assigned each actor an initial sum of money and created rules about the cost of emissions reductions. The goal of the simulation was to create an affordable timeline of emissions that kept the global temperature rise to less than 2 degrees C. Suggested emissions timelines were entered into the C-Learn online simulator during the activity to check progress toward the goal. Student feedback about the simulation was very positive. I had planned only one class period for the negotiations but students were so engaged that they asked for it to be extended into a second period. This exercise could easily be adapted to smaller or larger class sizes, and modified based on the knowledge base and experience level of the students.

Synopsis of Guidelines for the Clinical Management of Cerebral Cavernous Malformations: Consensus Recommendations Based on Systematic Literature Review by the Angioma Alliance Scientific Advisory Board Clinical Experts Panel

PubMed Central

Al-Shahi Salman, Rustam; A. Awad, Issam; Dahlem, Kristen; Flemming, Kelly; Hart, Blaine; Kim, Helen; Jusue-Torres, Ignacio; Kondziolka, Douglas; Lee, Cornelia; Morrison, Leslie; Rigamonti, Daniele; Rebeiz, Tania; Tournier-Lasserve, Elisabeth; Waggoner, Darrel; Whitehead, Kevin

2017-01-01

Abstract BACKGROUND: Despite many publications about cerebral cavernous malformations (CCMs), controversy remains regarding diagnostic and management strategies. OBJECTIVE: To develop guidelines for CCM management. METHODS: The Angioma Alliance (www.angioma.org), the patient support group in the United States advocating on behalf of patients and research in CCM, convened a multidisciplinary writing group comprising expert CCM clinicians to help summarize the existing literature related to the clinical care of CCM, focusing on 5 topics: (1) epidemiology and natural history, (2) genetic testing and counseling, (3) diagnostic criteria and radiology standards, (4) neurosurgical considerations, and (5) neurological considerations. The group reviewed literature, rated evidence, developed recommendations, and established consensus, controversies, and knowledge gaps according to a prespecified protocol. RESULTS: Of 1270 publications published between January 1, 1983 and September 31, 2014, we selected 98 based on methodological criteria, and identified 38 additional recent or relevant publications. Topic authors used these publications to summarize current knowledge and arrive at 23 consensus management recommendations, which we rated by class (size of effect) and level (estimate of certainty) according to the American Heart Association/American Stroke Association criteria. No recommendation was level A (because of the absence of randomized controlled trials), 11 (48%) were level B, and 12 (52%) were level C. Recommendations were class I in 8 (35%), class II in 10 (43%), and class III in 5 (22%). CONCLUSION: Current evidence supports recommendations for the management of CCM, but their generally low levels and classes mandate further research to better inform clinical practice and update these recommendations. The complete recommendations document, including the criteria for selecting reference citations, a more detailed justification of the respective recommendations, and a summary of controversies and knowledge gaps, was similarly peer reviewed and is available on line www.angioma.org/CCMGuidelines. PMID:28387823

Effect of particle size distribution on 3D packings of spherical particles

NASA Astrophysics Data System (ADS)

Taiebat, Mahdi; Mutabaruka, Patrick; Pellenq, Roland; Radjai, Farhang

2017-06-01

We use molecular dynamics simulations of frictionless spherical particles to investigate a class of polydisperse granular materials in which the particle size distribution is uniform in particle volumes. The particles are assembled in a box by uniaxial compaction under the action of a constant stress. Due to the absence of friction and the nature of size distribution, the generated packings have the highest packing fraction at a given size span, defined as the ratio α of the largest size to the smallest size. We find that, up to α = 5, the packing fraction is a nearly linear function of α. While the coordination number is nearly constant due to the isostatic nature of the packings, we show that the connectivity of the particles evolves with α. In particular, the proportion of particles with 4 contacts represents the largest proportion of particles mostly of small size. We argue that this particular class of particles occurs as a result of the high stability of local configurations in which a small particle is stuck by four larger particles.

Evaluating the Effectiveness of Lecture Capture: Lessons Learned from an Undergraduate Political Research Class

ERIC Educational Resources Information Center

Roberts, James C.

2015-01-01

This article presents the results of a 4-year quasi-experimental study of the effectiveness of lecture capture in an undergraduate political research class. Students self-enrolled in either a traditional in-class lecture-discussion section or a fully online section of a required political research course. The class sessions from the in-class…

Development and Modification of a Response Class via Positive and Negative Reinforcement: A Translational Approach

ERIC Educational Resources Information Center

Mendres, Amber E.; Borrero, John C.

2010-01-01

When responses function to produce the same reinforcer, a response class exists. Researchers have examined response classes in applied settings; however, the challenges associated with conducting applied research on response class development have recently necessitated the development of an analogue response class model. To date, little research…

Size-resolved ultrafine particle composition analysis 1. Atlanta

NASA Astrophysics Data System (ADS)

Rhoads, K. P.; Phares, D. J.; Wexler, A. S.; Johnston, M. V.

2003-04-01

During August 1999 as part of the Southern Oxidants Study Supersite Experiment, our group collected size-resolved measurements of the chemical composition of single ambient aerosol particles with a unique real-time laser desorption/ionization mass spectrometry technique. The rapid single-particle mass spectrometry instrument is capable of analyzing "ultrafine" particles with aerodynamic diameters ranging from 0.01 to 1.5 μm. Under the heaviest loading observed in Atlanta, particles were analyzed at a rate of roughly one per second in sizes ranging from 0.1 to 0.2 μm. Nearly 16,000 individual spectra were recorded over the course of the month during both daytime and nighttime sampling periods. Evaluation of the data indicates that the composition of the ultrafine (less than 100 nm) particles is dominated by carbon-containing compounds. Larger particles show varied compositions but typically appeared to have organic carbon characteristics mixed with an inorganic component (e.g., crustal materials, metals, etc.). During the experiment, 70 composition classes were identified. In this paper we report the average spectra and correlations with various meteorological parameters for all major compound classes and a number of minor ones. The major composition classes are identified from the primary peaks in their spectra as organic carbon (about 74% of the particles), potassium (8%), iron (3%), calcium (2%), nitrate (2%), elemental carbon (1.5%), and sodium (1%). Many of these compound classes appeared in repeatable size ranges and quadrants of the wind rose, indicating emission from specific sources.

Carbon Storage in Soil Size Fractions Under Two Cacao Agroforestry Systems in Bahia, Brazil

NASA Astrophysics Data System (ADS)

Gama-Rodrigues, Emanuela F.; Ramachandran Nair, P. K.; Nair, Vimala D.; Gama-Rodrigues, Antonio C.; Baligar, Virupax C.; Machado, Regina C. R.

2010-02-01

Shaded perennial agroforestry systems contain relatively high quantities of soil carbon (C) resulting from continuous deposition of plant residues; however, the extent to which the C is sequestered in soil will depend on the extent of physical protection of soil organic C (SOC). The main objective of this study was to characterize SOC storage in relation to soil fraction-size classes in cacao ( Theobroma cacao L.) agroforestry systems (AFSs). Two shaded cacao systems and an adjacent natural forest in reddish-yellow Oxisols in Bahia, Brazil were selected. Soil samples were collected from four depth classes to 1 m depth and separated by wet-sieving into three fraction-size classes (>250 μm, 250-53 μm, and <53 μm)—corresponding to macroaggregate, microaggregate, and silt-and-clay size fractions—and analyzed for C content. The total SOC stock did not vary among systems (mean: 302 Mg/ha). On average, 72% of SOC was in macroaggregate-size, 20% in microaggregate-size, and 8% in silt-and-clay size fractions in soil. Sonication of aggregates showed that occlusion of C in soil aggregates could be a major mechanism of C protection in these soils. Considering the low level of soil disturbances in cacao AFSs, the C contained in the macroaggregate fraction might become stabilized in the soil. The study shows the role of cacao AFSs in mitigating greenhouse gas (GHG) emission through accumulation and retention of high amounts of organic C in the soils and suggests the potential benefit of this environmental service to the nearly 6 million cacao farmers worldwide.

Carbon storage in soil size fractions under two cacao agroforestry systems in Bahia, Brazil.

PubMed

Gama-Rodrigues, Emanuela F; Ramachandran Nair, P K; Nair, Vimala D; Gama-Rodrigues, Antonio C; Baligar, Virupax C; Machado, Regina C R

2010-02-01

Shaded perennial agroforestry systems contain relatively high quantities of soil carbon (C) resulting from continuous deposition of plant residues; however, the extent to which the C is sequestered in soil will depend on the extent of physical protection of soil organic C (SOC). The main objective of this study was to characterize SOC storage in relation to soil fraction-size classes in cacao (Theobroma cacao L.) agroforestry systems (AFSs). Two shaded cacao systems and an adjacent natural forest in reddish-yellow Oxisols in Bahia, Brazil were selected. Soil samples were collected from four depth classes to 1 m depth and separated by wet-sieving into three fraction-size classes (>250 microm, 250-53 microm, and <53 microm)-corresponding to macroaggregate, microaggregate, and silt-and-clay size fractions-and analyzed for C content. The total SOC stock did not vary among systems (mean: 302 Mg/ha). On average, 72% of SOC was in macroaggregate-size, 20% in microaggregate-size, and 8% in silt-and-clay size fractions in soil. Sonication of aggregates showed that occlusion of C in soil aggregates could be a major mechanism of C protection in these soils. Considering the low level of soil disturbances in cacao AFSs, the C contained in the macroaggregate fraction might become stabilized in the soil. The study shows the role of cacao AFSs in mitigating greenhouse gas (GHG) emission through accumulation and retention of high amounts of organic C in the soils and suggests the potential benefit of this environmental service to the nearly 6 million cacao farmers worldwide.

Characterization of suspended particles in Everglades wetlands

USGS Publications Warehouse

Noe, G.B.; Harvey, J.W.; Saiers, J.E.

2007-01-01

We report the concentration, phosphorus (P) and nitrogen (N) content, and size and chemical fractionation of fine suspended particles (0.2-100 ??m) and colloids (3 kilodalton [kDa]-0.1 ??m) in the surface water of Everglades wetlands along regional and P-enrichment gradients. Total suspended sediment concentrations ranged from 0.7 to 2.7 mg L-1. Total particulate P concentrations increased from 0.05 ??mol L-1 to 0.31 ??mol L -1 along the P-enrichment gradient. Particles contained from 20% to 43% of total P but <12% of total N in surface water. Dissolved (<0.2 ??m) organic N contained about 90% of total N, with the 3-100-kDa colloidal size class containing the most N of any size class. The 0.45-2.7-??m size fraction held the most particulate P at all sites, whereas particulate N was most abundant in the 2.7-10-??m size class at most sites. Standard chemical fractionation of particles identified acid-hydrolyzable P as the most abundant species of particulate P, with little reactive or refractory organic P. Sequential chemical extraction revealed that about 65% of total particulate P was microbial, while about 25% was associated with humic and fulvic organic matter. The size and chemical fractionation information suggested that P-rich particles mostly consisted of suspended bacteria. Suspended particles in Everglades wetlands were small in size and had low concentrations, yet they stored a large proportion of surface-water P in intermediately reactive forms, but they held little N. ?? 2007, by the American Society of Limnology and Oceanography, Inc.

LandEx - Fast, FOSS-Based Application for Query and Retrieval of Land Cover Patterns

NASA Astrophysics Data System (ADS)

Netzel, P.; Stepinski, T.

2012-12-01

The amount of satellite-based spatial data is continuously increasing making a development of efficient data search tools a priority. The bulk of existing research on searching satellite-gathered data concentrates on images and is based on the concept of Content-Based Image Retrieval (CBIR); however, available solutions are not efficient and robust enough to be put to use as deployable web-based search tools. Here we report on development of a practical, deployable tool that searches classified, rather than raw image. LandEx (Landscape Explorer) is a GeoWeb-based tool for Content-Based Pattern Retrieval (CBPR) contained within the National Land Cover Dataset 2006 (NLCD2006). The USGS-developed NLCD2006 is derived from Landsat multispectral images; it covers the entire conterminous U.S. with the resolution of 30 meters/pixel and it depicts 16 land cover classes. The size of NLCD2006 is about 10 Gpixels (161,000 x 100,000 pixels). LandEx is a multi-tier GeoWeb application based on Open Source Software. Main components are: GeoExt/OpenLayers (user interface), GeoServer (OGC WMS, WCS and WPS server), and GRASS (calculation engine). LandEx performs search using query-by-example approach: user selects a reference scene (exhibiting a chosen pattern of land cover classes) and the tool produces, in real time, a map indicating a degree of similarity between the reference pattern and all local patterns across the U.S. Scene pattern is encapsulated by a 2D histogram of classes and sizes of single-class clumps. Pattern similarity is based on the notion of mutual information. The resultant similarity map can be viewed and navigated in a web browser, or it can download as a GeoTiff file for more in-depth analysis. The LandEx is available at http://sil.uc.edu

The effect of an enriched learning community on success and retention in chemistry courses

NASA Astrophysics Data System (ADS)

Willoughby, Lois Jane

Since the mid-1990s, the United States has experienced a shortage of scientists and engineers, declining numbers of students choosing these fields as majors, and low student success and retention rates in these disciplines. Learning theorists, educational researchers, and practitioners believe that learning environments can be created so that an improvement in the numbers of students who complete courses successfully could be attained (Astin, 1993; Magolda & Terenzini, n.d.; O'Banion, 1997). Learning communities do this by providing high expectations, academic and social support, feedback during the entire educational process, and involvement with faculty, other students, and the institution (Ketcheson & Levine, 1999). A program evaluation of an existing learning community of science, mathematics, and engineering majors was conducted to determine the extent to which the program met its goals and was effective from faculty and student perspectives. The program provided laptop computers, peer tutors, supplemental instruction with and without computer software, small class size, opportunities for contact with specialists in selected career fields, a resource library, and Peer-Led Team Learning. During the two years the project has existed, success, retention, and next-course continuation rates were higher than in traditional courses. Faculty and student interviews indicated there were many affective accomplishments as well. Success and retention rates for one learning community class ( n = 27) and one traditional class (n = 61) in chemistry were collected and compared using Pearson chi square procedures ( p = .05). No statistically significant difference was found between the two groups. Data from an open-ended student survey about how specific elements of their course experiences contributed to success and persistence were analyzed by coding the responses and comparing the learning community and traditional classes. Substantial differences were found in their perceptions about the lecture, the lab, other supports used for the course, contact with other students, helping them reach their potential, and their recommendation about the course to others. Because of the limitation of small sample size, these differences are reported in descriptive terms.

Plankton copper requirements and uptake in the subarctic Northeast Pacific Ocean

NASA Astrophysics Data System (ADS)

Semeniuk, David M.; Cullen, Jay T.; Johnson, W. Keith; Gagnon, Katie; Ruth, Thomas J.; Maldonado, Maria T.

2009-07-01

We undertook the first measurements of metabolic Cu requirements (net Cu:C assimilation ratios) and steady-state Cu uptake rates (ρCu ss) of natural plankton assemblages in the northeast subarctic Pacific using the short-lived radioisotope 67Cu. Size-fractionated net Cu:C assimilation ratios varied ˜3 fold (1.35-4.21 μmol Cu mol C -1) among the stations along Line P, from high Fe coastal waters to the Fe-limited open ocean. The variability in Cu:C was comparable to biogenic Fe:C ratios in this region. As previously observed for Fe uptake, the bacterial size class accounted for half of the total particulate ρCu ss. Interestingly, carbon biomass-normalized rates of Fe uptake from the siderophore desferrioxamine B (DFB) (ρFe DFB; a physiological proxy for Fe-limitation) by the >20 μm size class were positively correlated with the intracellular net Cu:C assimilation ratios in this size class, suggesting that intracellular Cu requirements for large phytoplankton respond to increased Fe-limitation. At Fe-limited Ocean Station Papa (OSP), we performed short-term Cu uptake (ρCu L) assays to determine the relative bioavailability of Cu bound to natural and synthetic ligands. Like the volumetric ρCu ss measured along Line P, the bacterial size class was responsible for at least 50% of the total ρCu L. Uptake rates of Cu from the various organic complexes suggest that Cu uptake was controlled by the oxidation state of the metal and by the metal:ligand concentration ratio, rather than the concentration of inorganic species of Cu in solution. Collectively, these data suggest that Cu likely plays an important role in the physiology of natural plankton communities beyond the toxicological effects studied previously.

Analytical design equations for self-tuned Class-E power amplifier.

PubMed

Hu, Zhe; Troyk, Philip

2011-01-01

For many emerging neural prosthesis designs that are powered by inductive coupling, their small physical size requires large current in the extracorporeal transmitter coil, and the Class-E power amplifier topology is often used for the transmitter design. Tuning of Class-E circuits for efficient operation is difficult and a self-tuned circuit can facilitate the tuning. The coil current is sensed and used to tune the switching of the transistor switch in the Class-E circuit in order to maintain its high-efficiency operation. Although mathematically complex, the analysis and design procedure for the self-tuned Class-E circuit can be simplified due to the current feedback control, which makes the phase angle between the switching pulse and the coil current predetermined. In this paper explicit analytical design equations are derived and a detailed design procedure is presented and compared with the conventional Class-E design approaches.

Construction and reconstruction concept in mathematics instruction

NASA Astrophysics Data System (ADS)

Mumu, Jeinne; Charitas Indra Prahmana, Rully; Tanujaya, Benidiktus

2017-12-01

The purpose of this paper is to describe two learning activities undertaken by lecturers, so that students can understand a mathematical concept. The mathematical concept studied in this research is the Vector Space in Linear Algebra instruction. Classroom Action Research used as a research method with pre-service mathematics teacher at University of Papua as the research subject. Student participants are divided into two parallel classes, 24 students in regular class, and remedial class consist of 18 students. Both approaches, construct and reconstruction concept, are implemented on both classes. The result shows that concept construction can only be done in regular class while in remedial class, learning with concept construction approach is not able to increase students' understanding on the concept taught. Understanding the concept of a student in a remedial class can only be carried out using the concept reconstruction approach.

Glycogen content in hepatocytes is related with their size in normal rat liver but not in cirrhotic one.

PubMed

Bezborodkina, Natalia N; Chestnova, Anna Yu; Vorobev, Mikhail L; Kudryavtsev, Boris N

2016-04-01

Hepatocytes differ from one another by the degree of the ploidy, size, position in the liver lobule, and level of the DNA-synthetic processes. It is believed, that the cell size exerts substantial influence on the metabolism of the hepatocytes and the glycogen content in them. The aim of the present study was to test this hypothesis. Dry weight of hepatocytes, their ploidy and glycogen content were determined in the normal and the cirrhotic rat liver. Liver cirrhosis in rats was produced by chronic inhalation of CCl4 vapours in the course of 6 months. A combined cytophotometric method was used. Dry weight of the cell, its glycogen and DNA content were successively measured on a mapped preparation. Hepatocytes of each ploidy class in the normal and the cirrhotic rat liver accumulated glycogen at the same rate. In the normal liver, there was a distinct correlation between the size of hepatocytes and glycogen content in them. This correlation was observed in each ploidy class, and was especially pronounced in the class of mononucleate tetraploid hepatocytes. In the cirrhotic liver, there was no correlation between the size of the cells and their glycogen content. The impairment of liver lobular structure probably explains the observed lack of correlation between hepatocyte size and their glycogen content in the cirrhotic liver. © 2016 International Society for Advancement of Cytometry. © 2016 International Society for Advancement of Cytometry.

Redefining Authentic Research Experiences in Introductory Biology Laboratories and Barriers to Their Implementation

PubMed Central

Spell, Rachelle M.; Guinan, Judith A.; Miller, Kristen R.; Beck, Christopher W.

2014-01-01

Incorporating authentic research experiences in introductory biology laboratory classes would greatly expand the number of students exposed to the excitement of discovery and the rigor of the scientific process. However, the essential components of an authentic research experience and the barriers to their implementation in laboratory classes are poorly defined. To guide future reform efforts in this area, we conducted a national survey of biology faculty members to determine 1) their definitions of authentic research experiences in laboratory classes, 2) the extent of authentic research experiences currently experienced in their laboratory classes, and 3) the barriers that prevent incorporation of authentic research experiences into these classes. Strikingly, the definitions of authentic research experiences differ among faculty members and tend to emphasize either the scientific process or the discovery of previously unknown data. The low level of authentic research experiences in introductory biology labs suggests that more development and support is needed to increase undergraduate exposure to research experiences. Faculty members did not cite several barriers commonly assumed to impair pedagogical reform; however, their responses suggest that expanded support for development of research experiences in laboratory classes could address the most common barrier. PMID:24591509

Redefining authentic research experiences in introductory biology laboratories and barriers to their implementation.

PubMed

Spell, Rachelle M; Guinan, Judith A; Miller, Kristen R; Beck, Christopher W

2014-01-01

Incorporating authentic research experiences in introductory biology laboratory classes would greatly expand the number of students exposed to the excitement of discovery and the rigor of the scientific process. However, the essential components of an authentic research experience and the barriers to their implementation in laboratory classes are poorly defined. To guide future reform efforts in this area, we conducted a national survey of biology faculty members to determine 1) their definitions of authentic research experiences in laboratory classes, 2) the extent of authentic research experiences currently experienced in their laboratory classes, and 3) the barriers that prevent incorporation of authentic research experiences into these classes. Strikingly, the definitions of authentic research experiences differ among faculty members and tend to emphasize either the scientific process or the discovery of previously unknown data. The low level of authentic research experiences in introductory biology labs suggests that more development and support is needed to increase undergraduate exposure to research experiences. Faculty members did not cite several barriers commonly assumed to impair pedagogical reform; however, their responses suggest that expanded support for development of research experiences in laboratory classes could address the most common barrier.

Sublethal foot-predation on Donacidae (Mollusca: Bivalvia)

NASA Astrophysics Data System (ADS)

Salas, Carmen; Tirado, Cristina; Manjón-Cabeza, Maria Eugenia

2001-08-01

The incidence of foot nipping was studied on the Donax spp. of the littoral of Málaga (Southern Spain, 2875 specimens collected from February 1990 to January 1991) and of Ré island (French Atlantic coast, 262 specimens of Donax vittatus (Da Costa, 1778) collected in May 1996). In Málaga, Donax trunculus L., 1758 was the species most regularly nipped (18% of individuals), with peaks in summer (25% in August and 48% in September) and winter (34% in December). In Ré island, 27% of the specimens showed a nipped foot. Logistic regression shows that in D. trunculus length is the variable that most influences the probability of foot nipping, followed by weight and chlorophyll a. However, the difference in length between damaged and undamaged individuals was not significant (U-Mann-Whitney test). The size class frequency and the values of Ivlev's index show that the small size classes were avoided, while for the other size classes predation remained balanced throughout the year. Therefore, the avoidance of the small size classes makes length the most influential variable. The logistic regression indicated a coefficient B=-0.03 for weight. This implies a slightly negative influence on the probability of foot nipping. However, without the data of September, there is a positive correlation ( r=0.76, p<0.01) between the monthly percentages of predation and the flesh dry weight of a standard individual (25 mm long). The peak in September could be due to the recruitment peak of bivalves, which may have attracted more predators to the area, and/or to the recruitment of predators such as crabs to the swash zone. Logistic regression and test of comparison of percentages indicate that there was not any influence of the sex of an animal on the probability of foot nipping. Only in February was a significantly higher percentage ( p<0.05) of females nipped (44.44%) than the total of females in the sample (20.20%). The biomass (as flesh dry weight) of D. trunculus lost by foot nipping amounts to more than 20% in most of the size classes. There was an increase from the small sizes to the largest ones, in which it reaches 37%, with a positive correlation ( r=0.84; p<0.005) between size class and loss of biomass. Possible predators responsible for the foot nipping are crabs. Crab species usually found together with the donacids were Portumnus latipes (Pennant, 1777) Liocarcinus vernalis (Risso, 1816) and Atelecyclus undecimdentatus (Herbst, 1783). In aquarium experiments, they demonstrated an ability to nip the foot of clams. Portumnus latipes was the most active foot nipper, but left alive all the damaged clams. Therefore, we conclude that crabs are the most likely foot-nipping predators in the field.

Global change technology architecture trade study

NASA Technical Reports Server (NTRS)

Garrett, L. Bernard (Editor); Hypes, Warren D. (Editor); Wright, Robert L. (Editor)

1991-01-01

Described here is an architecture trade study conducted by the Langley Research Center to develop a representative mix of advanced space science instrumentation, spacecraft, and mission orbits to assist in the technology selection processes. The analyses concentrated on the highest priority classes of global change measurements which are the global climate changes. Issues addressed in the tradeoffs includes assessments of the economics of scale of large platforms with multiple instruments relative to smaller spacecraft; the influences of current and possible future launch vehicles on payload sizes, and on-orbit assembly decisions; and the respective roles of low-Earth versus geostationary Earth orbiting systems.

Cost-Driven Design of a Large Scale X-Plane

NASA Technical Reports Server (NTRS)

Welstead, Jason R.; Frederic, Peter C.; Frederick, Michael A.; Jacobson, Steven R.; Berton, Jeffrey J.

2017-01-01

A conceptual design process focused on the development of a low-cost, large scale X-plane was developed as part of an internal research and development effort. One of the concepts considered for this process was the double-bubble configuration recently developed as an advanced single-aisle class commercial transport similar in size to a Boeing 737-800 or Airbus A320. The study objective was to reduce the contractor cost from contract award to first test flight to less than $100 million, and having the first flight within three years of contract award. Methods and strategies for reduced cost are discussed.

Office of the Secretary of Defense Research, Development Test and Evaluation, Development and Test Evaluation, Defense, Director of Operational Test and Evaluation Defense, FY 1994 Budget Estimates, Justification of Estimates Submitted to Congress April 1993

DTIC Science & Technology

1993-04-01

separation capability. o Demonstrate advanced KKVs in the 6-20 KG weight class. o Test planning for SRAM/LEAP and PATRIOT/LEAP integrated technology...packaging techniques to reduce satellite size, weight , power, and total system costs. Further development of these technologies are absolutely 4...1993 o Developed a master plan with a delivery schedule for each light- weight subassembly in the sensor integration payload. o Finalized a contract for

Multiphase chemistry in a microphysical radiation fog model—A numerical study

NASA Astrophysics Data System (ADS)

Bott, Andreas; Carmichael, Gregory R.

A microphysical radiation fog model is coupled with a detailed chemistry module to simulate chemical reactions in the gas phase and in fog water during a radiation fog event. In the chemical part of the model the microphysical particle spectrum is subdivided into three size classes corresponding to non-activated aerosol particles, small and large fog droplets. Chemical reactions in the liquid phase are separately calculated in the small and in the large droplet size class. The impact of the chemical constitution of activated aerosols on fogwater chemistry is considered in the model simulations. The mass transfer of chemical species between the gas phase and the two liquid phases is treated in detail by solving the corresponding coupled differential equation system. The model also accounts for concentration changes of gas-phase and aqueous-phase chemical species which are induced by turbulence, gravitational settling and by evaporation/condensation processes. Numerical results demonstrate that fogwater chemistry is strongly controlled by dynamic processes, i.e. the vertical growth of the fog, turbulent mixing processes and the gravitational settling of the particles. The concentrations of aqueous-phase chemical species are different in the two droplet size classes. Reactands with lower water solubility are mainly found in the large droplet size class because the characteristic time for their mass transfer from the gas phase into the liquid phase is essentially longer than the characteristic time for the formation of large fog droplets. Species with high water solubility are rapidly transferred into the small fog droplets and are then washed out by wet deposition before these particles grow further to form large droplets. Thus, the concentrations of the major ions (NO 3-, NH 4+) are much higher in small than in large droplets, yielding distinctly lower pH values of the small particles. In the present study the reaction of sulfur with H 2O 2 and the Fe(III)-catalysed autoxidation of S(IV) are the major S(VI) producing mechanisms in fog water. Most of the time the sulfur oxidation rates are higher in the large than in the small droplets. Fogwater deposition by gravitational settling occurs mainly in the large droplet size class. However, since in the small droplets the concentrations of chemical species with very good water solubility are relatively high, in both droplet size classes the total wet deposition of these reactands is of the same order of magnitude.

Preliminary design of nine high speed civil transports

NASA Technical Reports Server (NTRS)

Sandlin, Doral; Vantriet, Robert; Soban, Dani; Hoang, TY

1992-01-01

Sixty senior design students at Cal Poly, SLO have completed a year-long project to design the next generation of High Speed Civil Transports (HSCT). The design process was divided up into three distinct phases. The first third of the project was devoted entirely to research into the special problems associated with an HSCT. These included economic viability, airport compatibility, high speed aerodynamics, sonic boom minimization, environmental impact, and structures and materials. The result of this research was the development of nine separate Requests for Proposal (RFP) that outlined reasonable yet challenging design criteria for the aircraft. All were designed to be technically feasible in the year 2015. The next phase of the project divided the sixty students into nine design groups. Each group, with its own RFP, completed a Class 1 preliminary design of an HSCT. The nine configurations varied from conventional double deltas to variable geometry wings to a pivoting oblique wing design. The final phase of the project included a more detailed Class 2 sizing as well as performance and stability and control analysis. Cal Poly, San Luis Obispo presents nine unique solutions to the same problem: that of designing an economically viable, environmentally acceptable, safe and comfortable supersonic transport.

Diagnostic accuracy of different display types in detection of recurrent caries under restorations by using CBCT.

PubMed

Baltacıoĝlu, İsmail H; Eren, Hakan; Yavuz, Yasemin; Kamburoğlu, Kıvanç

To assess the in vitro diagnostic ability of CBCT images using seven different display types in the detection of recurrent caries. Our study comprised 128 extracted human premolar and molar teeth. 8 groups each containing 16 teeth were obtained as follows: (1) Black Class I (Occlusal) amalgam filling without caries; (2) Black Class I (Occlusal) composite filling without caries; (3) Black Class II (Proximal) amalgam filling without caries; (4) Black Class II (Proximal) composite filling without caries; (5) Black Class I (Occlusal) amalgam filling with caries; (6) Black Class I (Occlusal) composite filling with caries; (7) Black Class II (Proximal) amalgam filling with caries; and (8) Black Class II (Proximal) composite filling with caries. Teeth were imaged using 100 × 90 mm field of view at three different voxel sizes of a CBCT unit (Planmeca ProMax(®) 3D ProFace™; Planmeca, Helsinki, Finland). CBCT TIFF images were opened and viewed using custom-designed software for computers on different display types. Intra- and interobserver agreements were calculated. The highest area under the receiver operating characteristic curve (Az) values for each image type, observer, reading and restoration were compared using z-tests against Az = 0.5. The significance level was set at p = 0.05. We found poor and moderate agreements. In general, Az values were found when software and medical diagnostic monitor were utilized. For Observer 2, Az values were statistically significantly higher when software was used on medical monitor [p = 0.036, p = 0.015 and p = 0.002, for normal-resolution mode (0.200 mm(3) voxel size), high-resolution mode (0.150 mm(3) voxel size) and low-resolution mode (0.400 mm(3) voxel size), respectively]. No statistically significant differences were found among other display types for all modes (p > 0.05). In general, no difference was found among 3 different voxel sizes (p > 0.05). In general, higher Az values were obtained for composite restorations than for amalgam restorations for all observers. For Observer 1, Az values for composite restorations were statistically significantly higher than those of amalgam restorations for MacBook and iPhone (Apple Inc., Cupertino, CA) assessments (p = 0.002 and p = 0.048, respectively). Higher Az values were observed with medical monitors when used with dedicated software compared to other display types which performed similarly in the diagnosis of recurrent caries under restorations. In addition, observers performed better in detection of recurrent caries when assessing composite restorations than amalgams.

Diagnostic accuracy of different display types in detection of recurrent caries under restorations by using CBCT

PubMed Central

Baltacıoĝlu, İsmail H; Eren, Hakan; Yavuz, Yasemin

2016-01-01

Objectives: To assess the in vitro diagnostic ability of CBCT images using seven different display types in the detection of recurrent caries. Methods: Our study comprised 128 extracted human premolar and molar teeth. 8 groups each containing 16 teeth were obtained as follows: (1) Black Class I (Occlusal) amalgam filling without caries; (2) Black Class I (Occlusal) composite filling without caries; (3) Black Class II (Proximal) amalgam filling without caries; (4) Black Class II (Proximal) composite filling without caries; (5) Black Class I (Occlusal) amalgam filling with caries; (6) Black Class I (Occlusal) composite filling with caries; (7) Black Class II (Proximal) amalgam filling with caries; and (8) Black Class II (Proximal) composite filling with caries. Teeth were imaged using 100 × 90 mm field of view at three different voxel sizes of a CBCT unit (Planmeca ProMax® 3D ProFace™; Planmeca, Helsinki, Finland). CBCT TIFF images were opened and viewed using custom-designed software for computers on different display types. Intra- and interobserver agreements were calculated. The highest area under the receiver operating characteristic curve (Az) values for each image type, observer, reading and restoration were compared using z-tests against Az = 0.5. The significance level was set at p = 0.05. Results: We found poor and moderate agreements. In general, Az values were found when software and medical diagnostic monitor were utilized. For Observer 2, Az values were statistically significantly higher when software was used on medical monitor [p = 0.036, p = 0.015 and p = 0.002, for normal-resolution mode (0.200 mm3 voxel size), high-resolution mode (0.150 mm3 voxel size) and low-resolution mode (0.400 mm3 voxel size), respectively]. No statistically significant differences were found among other display types for all modes (p > 0.05). In general, no difference was found among 3 different voxel sizes (p > 0.05). In general, higher Az values were obtained for composite restorations than for amalgam restorations for all observers. For Observer 1, Az values for composite restorations were statistically significantly higher than those of amalgam restorations for MacBook and iPhone (Apple Inc., Cupertino, CA) assessments (p = 0.002 and p = 0.048, respectively). Conclusions: Higher Az values were observed with medical monitors when used with dedicated software compared to other display types which performed similarly in the diagnosis of recurrent caries under restorations. In addition, observers performed better in detection of recurrent caries when assessing composite restorations than amalgams. PMID:27319604

The effectivenes of science domain-based science learning integrated with local potency

NASA Astrophysics Data System (ADS)

Kurniawati, Arifah Putri; Prasetyo, Zuhdan Kun; Wilujeng, Insih; Suryadarma, I. Gusti Putu

2017-08-01

This research aimed to determine the significant effect of science domain-based science learning integrated with local potency toward science process skills. The research method used was a quasi-experimental design with nonequivalent control group design. The population of this research was all students of class VII SMP Negeri 1 Muntilan. The sample of this research was selected through cluster random sampling, namely class VII B as an experiment class (24 students) and class VII C as a control class (24 students). This research used a test instrument that was adapted from Agus Dwianto's research. The aspect of science process skills in this research was observation, classification, interpretation and communication. The analysis of data used the one factor anova at 0,05 significance level and normalized gain score. The significance level result of science process skills with one factor anova is 0,000. It shows that the significance level < alpha (0,05). It means that there was significant effect of science domain-based science learning integrated with local potency toward science learning process skills. The results of analysis show that the normalized gain score are 0,29 (low category) in control class and 0,67 (medium category) in experiment class.

The prevalence of domestic violence within different socio-economic classes in Central Trinidad.

PubMed

Nagassar, R P; Rawlins, J M; Sampson, N R; Zackerali, J; Chankadyal, K; Ramasir, C; Boodram, R

2010-01-01

Domestic violence is a medical and social issue that often leads to negative consequences for society. This paper examines the association between the prevalence of domestic violence in relation to the different socio-economic classes in Central Trinidad. The paper also explores the major perceived causes of physical abuse in Central Trinidad. Participants were selected using a two-stage stratified sampling method within the Couva district. Households, each contributing one participant, were stratified into different socioeconomic classes (SES Class) and each stratum size (or its share in the sample) was determined by the portion of its size in the sampling frame to the total sample; then its members were randomly selected. The sampling method attempted to balance and then minimize racial, age, cultural biases and confounding factors. The participant chosen had to be older than 16-years of age, female and a resident of the household. If more than one female was at home, the most senior was interviewed. The study found a statistically significant relationship between verbal abuse (p = 0.0017), physical abuse (p = 0.0012) and financial abuse (p = 0.001) and socio-economic class. For all the socio-economic classes considered, the highest prevalence of domestic violence occurred amongst the working class and lower middle socio-economic classes. The most prominent reasons cited for the physical violence was drug and alcohol abuse (37%) and communication differences (16.3%). These were the other two main perceived causes of the violence. The power of the study was 0.78 and the all strata prevalence of domestic violence was 41%. Domestic violence was reported within all socio-economic class groupings but it was most prevalent within the working class and lower middle socio-economic classes. The major perceived cause of domestic violence was alcohol/drug abuse.

Inter-class competition in stage-structured populations: effects of adult density on life-history traits of adult and juvenile common lizards.

PubMed

San-Jose, Luis M; Peñalver-Alcázar, Miguel; Huyghe, Katleen; Breedveld, Merel C; Fitze, Patrick S

2016-12-01

Ecological and evolutionary processes in natural populations are largely influenced by the population's stage-structure. Commonly, different classes have different competitive abilities, e.g., due to differences in body size, suggesting that inter-class competition may be important and largely asymmetric. However, experimental evidence states that inter-class competition, which is important, is rare and restricted to marine fish. Here, we manipulated the adult density in six semi-natural populations of the European common lizard, Zootoca vivipara, while holding juvenile density constant. Adult density affected juveniles, but not adults, in line with inter-class competition. High adult density led to lower juvenile survival and growth before hibernation. In contrast, juvenile survival after hibernation was higher in populations with high adult density, pointing to relaxed inter-class competition. As a result, annual survival was not affected by adult density, showing that differences in pre- and post-hibernation survival balanced each other out. The intensity of inter-class competition affected reproduction, performance, and body size in juveniles. Path analyses unravelled direct treatment effects on early growth (pre-hibernation) and no direct treatment effects on the parameters measured after hibernation. This points to allometry of treatment-induced differences in early growth, and it suggests that inter-class competition mainly affects the early growth of the competitively inferior class and thereby their future performance and reproduction. These results are in contrast with previous findings and, together with results in marine fish, suggest that the strength and direction of density dependence may depend on the degree of inter-class competition, and thus on the availability of resources used by the competing classes.

Estimates of downed woody debris decay class transitions for forests across the eastern United States

Treesearch

Matthew B. Russell; Christopher W. Woodall; Shawn Fraver; Anthony W. D' Amato

2013-01-01

Large-scale inventories of downed woody debris (DWD; downed dead wood of a minimum size) often record decay status by assigning pieces to classes of decay according to their visual/structural attributes (e.g., presence of branches, log shape, and texture and color of wood). DWD decay classes are not only essential for estimating current DWD biomass and carbon stocks,...

A numerical rating system for crown classes of southern hardwoods

Treesearch

James S. Meadows; E.C. Burkhardt; Robert L. Johnson; John D. Hodges

2001-01-01

A numerical rating system to delineate crown classes of southern hardwoods is described. The system is based on four criteria: (1) amount of direct sunlight from above, (2) amount of direct sunlight from the sides, (3) crown balance, and (4) relative crown size. The total point value assigned places the tree within one of the four crown classes. The rating system can...

Active Learning and Just-in-Time Teaching in a Material and Energy Balances Course

ERIC Educational Resources Information Center

Liberatore, Matthew W.

2013-01-01

The delivery of a material and energy balances course is enhanced through a series of in-class and out-of-class exercises. An active learning classroom is achieved, even at class sizes over 150 students, using multiple instructors in a single classroom, problem solving in teams, problems based on YouTube videos, and just-in-time teaching. To avoid…

[Diet composition and ontogenetic variation in feeding habits of Cleithenes herzensteini in central Yellow Sea].

PubMed

Zhang, Bo

2007-08-01

In the bottom trawl surveys in central Yellow Sea from January 2004 to October 2005, 622 samples of plaice Cleithenes herzensteini were collected, and their stomach contents were analyzed. The results indicated that the prey items of the plaice included 11 groups or 38 prey species, but only Crustacea and Lamellibranchia were the most important prey groups, accounting for 99% of the total food composition by percentage of index of relative importance. Euphausia pacific, Crangon affinis and Tellinidae were the dominant prey species. Comparing with the 1980s, the feeding activity of plaice declined significantly, and the diet composition changed. Fishes were no longer the dominant prey, and the proportion of anchovy in the diet decreased. Cluster analysis and two-way contingency table analysis were used to study the ontogenetic variations in the feeding habits of plaice, and the results showed that the feeding activity of plaice did not vary significantly among 7 size classes within the size between 51 mm and 370 mm, but ontogenetic variations were found in the diet composition. In the size class < 119 mm, the diet mainly included Euphausiacea and Decapoda. In the diets of fish with the size between 120 mm and 199 mm, the proportion of Lamellibranchia and fishes increased markedly. In the size class > 200 mm, plaice mainly fed on Decapoda and fishes.