WorldWideScience

Sample records for reported effect size

  1. Interpreting and Reporting Effect Sizes in Research Investigations.

    Science.gov (United States)

    Tapia, Martha; Marsh, George E., II

    Since 1994, the American Psychological Association (APA) has advocated the inclusion of effect size indices in reporting research to elucidate the statistical significance of studies based on sample size. In 2001, the fifth edition of the APA "Publication Manual" stressed the importance of including an index of effect size to clarify…

  2. Reporting effect sizes as a supplement to statistical significance ...

    African Journals Online (AJOL)

    The purpose of the article is to review the statistical significance reporting practices in reading instruction studies and to provide guidelines for when to calculate and report effect sizes in educational research. A review of six readily accessible (online) and accredited journals publishing research on reading instruction ...

  3. Reporting and Interpreting Effect Size in Quantitative Agricultural Education Research

    Science.gov (United States)

    Kotrlik, Joe W.; Williams, Heather A.; Jabor, M. Khata

    2011-01-01

    The Journal of Agricultural Education (JAE) requires authors to follow the guidelines stated in the Publication Manual of the American Psychological Association [APA] (2009) in preparing research manuscripts, and to utilize accepted research and statistical methods in conducting quantitative research studies. The APA recommends the reporting of…

  4. A descriptive study of effect-size reporting in research reviews.

    Science.gov (United States)

    Floyd, Judith A

    2017-06-01

    To describe effect-size reporting in research reviews completed in support of evidence-based practice in nursing. Many research reviews report nurses' critical appraisal of level, quality and overall strength of evidence available to address clinical questions. Several studies of research-review quality suggest effect-size information would be useful to include in these reviews, but none focused on reviewers' attention to effect sizes. Descriptive. One hundred and four reviews indexed in CINAHL as systematic reviews and published from July 2012-February 2014 were examined. Papers were required to be peer-reviewed, written in English, contain an abstract and have at least one nurse author. Reviews were excluded if they did not use critical appraisal methods to address evidence of correlation, prediction or effectiveness. Data from remaining papers (N = 73) were extracted by three or more independent coders using a structured coding form and detailed codebook. Data were stored, viewed and analysed using Microsoft Office Excel ® spreadsheet functions. Sixteen percent (n = 12) of the sample contained effect-size information. Of the 12, six included all the effect-size information recommended by APA guidelines. Independent of completeness of reporting, seven contained discussion of effect sizes in the paper, but none included effect-size information in abstracts. Research reviews available to practicing nurses often fail to include information needed to accurately assess how much improvement may result from implementation of evidence-based policies, programs, protocols or practices. Manuscript reviewers are urged to hold authors to APA standards for reporting/discussing effect-size information in both primary research reports and research reviews. © 2016 John Wiley & Sons Ltd.

  5. The Impact of APA and AERA Guidelines on Effect Size Reporting

    Science.gov (United States)

    Peng, Chao-Ying Joanne; Chen, Li-Ting; Chiang, Hsu-Min; Chiang, Yi-Chen

    2013-01-01

    Given the long history of effect size (ES) indices (Olejnik and Algina, "Contemporary Educational Psychology," 25, 241-286 2000) and various attempts by APA and AERA to encourage the reporting and interpretation of ES to supplement findings from inferential statistical analyses, it is essential to document the impact of APA and AERA standards on…

  6. The effect of journal impact factor, reporting conflicts, and reporting funding sources, on standardized effect sizes in back pain trials: a systematic review and meta-regression.

    Science.gov (United States)

    Froud, Robert; Bjørkli, Tom; Bright, Philip; Rajendran, Dévan; Buchbinder, Rachelle; Underwood, Martin; Evans, David; Eldridge, Sandra

    2015-11-30

    Low back pain is a common and costly health complaint for which there are several moderately effective treatments. In some fields there is evidence that funder and financial conflicts are associated with trial outcomes. It is not clear whether effect sizes in back pain trials relate to journal impact factor, reporting conflicts of interest, or reporting funding. We performed a systematic review of English-language papers reporting randomised controlled trials of treatments for non-specific low back pain, published between 2006-2012. We modelled the relationship using 5-year journal impact factor, and categories of reported of conflicts of interest, and categories of reported funding (reported none and reported some, compared to not reporting these) using meta-regression, adjusting for sample size, and publication year. We also considered whether impact factor could be predicted by the direction of outcome, or trial sample size. We could abstract data to calculate effect size in 99 of 146 trials that met our inclusion criteria. Effect size is not associated with impact factor, reporting of funding source, or reporting of conflicts of interest. However, explicitly reporting 'no trial funding' is strongly associated with larger absolute values of effect size (adjusted β=1.02 (95 % CI 0.44 to 1.59), P=0.001). Impact factor increases by 0.008 (0.004 to 0.012) per unit increase in trial sample size (Psources of funding, and conflicts of interest reflects positively on research and publisher conduct in the field. Strong evidence of a large association between absolute magnitude of effect size and explicit reporting of 'no funding' suggests authors of unfunded trials are likely to report larger effect sizes, notwithstanding direction. This could relate in part to quality, resources, and/or how pragmatic a trial is.

  7. Meta-Analysis of Effect Sizes Reported at Multiple Time Points Using General Linear Mixed Model

    Science.gov (United States)

    Musekiwa, Alfred; Manda, Samuel O. M.; Mwambi, Henry G.; Chen, Ding-Geng

    2016-01-01

    Meta-analysis of longitudinal studies combines effect sizes measured at pre-determined time points. The most common approach involves performing separate univariate meta-analyses at individual time points. This simplistic approach ignores dependence between longitudinal effect sizes, which might result in less precise parameter estimates. In this paper, we show how to conduct a meta-analysis of longitudinal effect sizes where we contrast different covariance structures for dependence between effect sizes, both within and between studies. We propose new combinations of covariance structures for the dependence between effect size and utilize a practical example involving meta-analysis of 17 trials comparing postoperative treatments for a type of cancer, where survival is measured at 6, 12, 18 and 24 months post randomization. Although the results from this particular data set show the benefit of accounting for within-study serial correlation between effect sizes, simulations are required to confirm these results. PMID:27798661

  8. Failure to Report Effect Sizes: The Handling of Quantitative Results in Published Health Education and Behavior Research.

    Science.gov (United States)

    Barry, Adam E; Szucs, Leigh E; Reyes, Jovanni V; Ji, Qian; Wilson, Kelly L; Thompson, Bruce

    2016-10-01

    Given the American Psychological Association's strong recommendation to always report effect sizes in research, scholars have a responsibility to provide complete information regarding their findings. The purposes of this study were to (a) determine the frequencies with which different effect sizes were reported in published, peer-reviewed articles in health education, promotion, and behavior journals and (b) discuss implications for reporting effect size in social science research. Across a 4-year time period (2010-2013), 1,950 peer-reviewed published articles were examined from the following six health education and behavior journals: American Journal of Health Behavior, American Journal of Health Promotion, Health Education & Behavior, Health Education Research, Journal of American College Health, and Journal of School Health Quantitative features from eligible manuscripts were documented using Qualtrics online survey software. Of the 1,245 articles in the final sample that reported quantitative data analyses, approximately 47.9% (n = 597) of the articles reported an effect size. While 16 unique types of effect size were reported across all included journals, many of the effect sizes were reported with little frequency across most journals. Overall, odds ratio/adjusted odds ratio (n = 340, 50.1%), Pearson r/r(2) (n = 162, 23.8%), and eta squared/partial eta squared (n = 46, 7.2%) accounted for the most frequently used effect size. Quality research practice requires both testing statistical significance and reporting effect size. However, our study shows that a substantial portion of published literature in health education and behavior lacks consistent reporting of effect size. © 2016 Society for Public Health Education.

  9. Exploiting finite-size-effects to simulate full QCD with light quarks - a progress report

    International Nuclear Information System (INIS)

    Orth, B.; Eicker, N.; Lippert, Th.; Schilling, K.; Schroers, W.; Sroczynski, Z.

    2002-01-01

    We present a report on the status of the GRAL project (Going Realistic And Light), which aims at simulating full QCD with two dynamical Wilson quarks below the vector meson decay threshold, m ps /m v < 0.5, making use of finite-size-scaling techniques

  10. Effect of specimen size on the fracture toughness of Type 304 stainless steel. Interim report

    International Nuclear Information System (INIS)

    Mills, W.J.

    1982-02-01

    The effect of specimen size on the elastic-plastic fracture toughness behavior of Type 304 stainless steel was characterized by the multiple-specimen J-R curve technique at 427 0 C. Fracture tests were performed on five compact specimen sizes: 2.5T (thickness = 63.5 mm), 2.5T (thickness = 14.7 mm), 1T (thickness = 25.4 mm), 1T (thickness = 14.7 mm), and 0.577 (thickness = 14.7 mm). In comparison with the 63.5-mm thick 2.5T specimen results, the smaller specimens exhibited higher J/sub Ic values and lower R-curve slopes (dJ/da). However, the differences in J/sub Ic/ and dJ/da were not statistically significant for the 2.5T and 1T specimens, which suggests that size effects for 1T and larger specimens are relatively small or nonexistant. On the other hand, there was a statistical difference between the 0.577T and 2.5T J/sub Ic/ values

  11. A Primer on Basic Effect Size Concepts.

    Science.gov (United States)

    Elmore, Patricia B.; Rotou, Ourania

    The increased interest in reporting effect sizes means that it is necessary to consider what should be included in a primer on effect sizes. A review of papers on effect sizes and commonly repeated statistical analyses suggests that it is important to discuss effect sizes relative to bivariate correlation, t-tests, analysis of variance/covariance,…

  12. Effect Sizes in Gifted Education Research

    Science.gov (United States)

    Gentry, Marcia; Peters, Scott J.

    2009-01-01

    Recent calls for reporting and interpreting effect sizes have been numerous, with the 5th edition of the "Publication Manual of the American Psychological Association" (2001) calling for the inclusion of effect sizes to interpret quantitative findings. Many top journals have required that effect sizes accompany claims of statistical significance.…

  13. Size effects in electrochemistry

    International Nuclear Information System (INIS)

    Petrii, Oleg A; Tsirlina, Galina A

    2001-01-01

    General characteristics of size-dependent phenomena in electrochemical systems are given. Primary attention is paid to methodical achievements of nanoelectrochemistry, which is a line of research created over the last 15 years. The development of the main concepts of electrochemistry initiated by the stream of nanoscopic information is considered. The prospects for local studies of processes on charged interfaces, elementary steps of these processes and application of nanoelectrodes and related systems in interdisciplinary fields are discussed. The bibliography includes 198 references.

  14. The effect of reported high-velocity small raindrops on inferred drop size distributions and derived power laws

    Directory of Open Access Journals (Sweden)

    H. Leijnse

    2010-07-01

    Full Text Available It has recently been shown that at high rainfall intensities, small raindrops may fall with much larger velocities than would be expected from their diameters. These were argued to be fragments of recently broken-up larger drops. In this paper we quantify the effect of this phenomenon on raindrop size distribution measurements from a Joss-Waldvogel disdrometer, a 2-D Video Distrometer, and a vertically-pointing Doppler radar. Probability distributions of fall velocities have been parameterized, where the parameters are functions of both rainfall intensity and drop size. These parameterizations have been used to correct Joss-Waldvogel disdrometer measurements for this phenomenon. The effect of these corrections on fitted scaled drop size distributions are apparent but not major. Fitted gamma distributions for three different types of rainfall have been used to simulate drop size measurements. The effect of the high-velocity small drops is shown to be minor. Especially for the purpose of remote sensing of rainfall using radar, microwave links, or optical links, the errors caused by using the slightly different retrieval relations will be masked completely by other error sources.

  15. Size effects in shear interfaces

    OpenAIRE

    GARNIER, J

    2001-01-01

    In physical modelling (centrifuge tests, calibration chambers, laboratory tests), the size of the soil particles may not be negligible when compared to the dimensions of the models. Size effects may so disturb the response of the models and the experimental data obtained on these cannot be extended to true scale conditions. Different tests have been performed to study and quantify the size effects that may happen in shear interfaces between soils and structures : modified shear box tests, pul...

  16. Particle size distribution instrument. Topical report 13

    Energy Technology Data Exchange (ETDEWEB)

    Okhuysen, W.; Gassaway, J.D.

    1995-04-01

    The development of an instrument to measure the concentration of particles in gas is described in this report. An in situ instrument was designed and constructed which sizes individual particles and counts the number of occurrences for several size classes. Although this instrument was designed to detect the size distribution of slag and seed particles generated at an experimental coal-fired magnetohydrodynamic power facility, it can be used as a nonintrusive diagnostic tool for other hostile industrial processes involving the formation and growth of particulates. Two of the techniques developed are extensions of the widely used crossed beam velocimeter, providing simultaneous measurement of the size distribution and velocity of articles.

  17. Shift from National Reporting to Reporting in Accordance with International Financial Reporting Standard for Small and Medium-sized Entities and Its Effect on Financial Management – the Case of the Czech Republic

    Directory of Open Access Journals (Sweden)

    Struhařová Kateřina

    2010-12-01

    Full Text Available The aim of this paper is to evaluate the effect of the shift from Financial Reporting under the Czech legislature (CZ GAAP to the International Financial Reporting Standard for financial management in Small and Medium-sized Enterprises (IFRS for SMEs. The reasons for the shift and major differences between CZ GAAP and IFRS for SMEs are mentioned, as well as the changes relevant to the shift. Not only changes in accounting departments are defined but also the changes that affect a company as a whole. Furthermore, information from Financial Reporting used in Financial Management is described. Also, the effect of the changes in Financial Reporting on this information and related modifications affecting Financial Management are evaluated.

  18. Size effects in crystal plasticity

    DEFF Research Database (Denmark)

    Borg, Ulrik

    2007-01-01

    Numerical analyses of plasticity size effects have been carried out for different problems using a developed strain gradient crystal plasticiy theory. The theory employs higher order stresses as work conjugates to slip gradients and uses higher order boundary conditions. Problems on localization...... of plastic flow in a single crystal, grain boundary effects in a bicrystal, and grain size effects in a polycrystal are studied. Single crystals containing micro-scale voids have also been analyzed at different loading conditions with focus on the stress and deformation fields around the voids, on void...... growth and interaction between neighboring voids, and on a comparison between the developed strain gradient crystal plasticity theory and a discrete dislocation plasticity theory. Furthermore, voids and rigid inclusions in isotropic materials have been studied using a strain gradient plasticity theory...

  19. How to Estimate and Interpret Various Effect Sizes

    Science.gov (United States)

    Vacha-Haase, Tammi; Thompson, Bruce

    2004-01-01

    The present article presents a tutorial on how to estimate and interpret various effect sizes. The 5th edition of the Publication Manual of the American Psychological Association (2001) described the failure to report effect sizes as a "defect" (p. 5), and 23 journals have published author guidelines requiring effect size reporting. Although…

  20. Effect size estimates: current use, calculations, and interpretation.

    Science.gov (United States)

    Fritz, Catherine O; Morris, Peter E; Richler, Jennifer J

    2012-02-01

    The Publication Manual of the American Psychological Association (American Psychological Association, 2001, American Psychological Association, 2010) calls for the reporting of effect sizes and their confidence intervals. Estimates of effect size are useful for determining the practical or theoretical importance of an effect, the relative contributions of factors, and the power of an analysis. We surveyed articles published in 2009 and 2010 in the Journal of Experimental Psychology: General, noting the statistical analyses reported and the associated reporting of effect size estimates. Effect sizes were reported for fewer than half of the analyses; no article reported a confidence interval for an effect size. The most often reported analysis was analysis of variance, and almost half of these reports were not accompanied by effect sizes. Partial η2 was the most commonly reported effect size estimate for analysis of variance. For t tests, 2/3 of the articles did not report an associated effect size estimate; Cohen's d was the most often reported. We provide a straightforward guide to understanding, selecting, calculating, and interpreting effect sizes for many types of data and to methods for calculating effect size confidence intervals and power analysis.

  1. Size effects on cavitation instabilities

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2006-01-01

    growth is here analyzed for such cases. A finite strain generalization of a higher order strain gradient plasticity theory is applied for a power-law hardening material, and the numerical analyses are carried out for an axisymmetric unit cell containing a spherical void. In the range of high stress...... triaxiality, where cavitation instabilities are predicted by conventional plasticity theory, such instabilities are also found for the nonlocal theory, but the effects of gradient hardening delay the onset of the instability. Furthermore, in some cases the cavitation stress reaches a maximum and then decays...... as the void grows to a size well above the characteristic material length....

  2. Hit size effectiveness in relation to the microdosimetric site size

    International Nuclear Information System (INIS)

    Varma, M.N.; Wuu, C.S.; Zaider, M.

    1994-01-01

    This paper examines the effect of site size (that is, the diameter of the microdosimetric volume) on the hit size effectiveness function (HSEF), q(y), for several endpoints relevant in radiation protection. A Bayesian and maximum entropy approach is used to solve the integral equations that determine, given microdosimetric spectra and measured initial slopes, the function q(y). All microdosimetric spectra have been calculated de novo. The somewhat surprising conclusion of this analysis is that site size plays only a minor role in selecting the hit size effectiveness function q(y). It thus appears that practical means (e.g. conventional proportional counters) are already at hand to actually implement the HSEF as a radiation protection tool. (Author)

  3. Publication Bias in Psychology: A Diagnosis Based on the Correlation between Effect Size and Sample Size

    Science.gov (United States)

    Kühberger, Anton; Fritz, Astrid; Scherndl, Thomas

    2014-01-01

    Background The p value obtained from a significance test provides no information about the magnitude or importance of the underlying phenomenon. Therefore, additional reporting of effect size is often recommended. Effect sizes are theoretically independent from sample size. Yet this may not hold true empirically: non-independence could indicate publication bias. Methods We investigate whether effect size is independent from sample size in psychological research. We randomly sampled 1,000 psychological articles from all areas of psychological research. We extracted p values, effect sizes, and sample sizes of all empirical papers, and calculated the correlation between effect size and sample size, and investigated the distribution of p values. Results We found a negative correlation of r = −.45 [95% CI: −.53; −.35] between effect size and sample size. In addition, we found an inordinately high number of p values just passing the boundary of significance. Additional data showed that neither implicit nor explicit power analysis could account for this pattern of findings. Conclusion The negative correlation between effect size and samples size, and the biased distribution of p values indicate pervasive publication bias in the entire field of psychology. PMID:25192357

  4. Calculating and reporting effect sizes on scientific papers (1: p < 0.05 limitations in the analysis of mean differences of two groups

    Directory of Open Access Journals (Sweden)

    Helena Espirito Santo

    2015-02-01

    Since p-values from the results of the statistical tests do not indicate the magnitude or importance of a difference, then effect sizes (ES should reported. In fact, ES give meaning to statistical tests; emphasize the power of statistical tests; reduce the risk of interpret mere sampling variation as real relationship; can increase the reporting of “non-significant"results, and allow the accumulation of knowledge from several studies using meta-analysis. Thus, the objectives of this paper are to present the limits of the significance level; describe the foundations of presentation of ES of statistical tests to analyze differences between two groups; present the formulas to calculate directly ES, providing examples of our own previous studies; show how to calculate confidence intervals; provide the conversion formulas for the review of the literature; indicate how to interpret the ES; and show that, although interpretable, the meaning (small, medium or large effect for an arbitrary metric could be inaccurate, requiring that interpretation should be made in the context of the research area and in the context of real world variables.

  5. Size Effects on the Strength of Metals

    DEFF Research Database (Denmark)

    Huang, Xiaoxu

    2014-01-01

    The grain size effect and the specimen size effect on the strength of metals are briefly reviewed with respect to their history and current status of research. It is revealed that the fundamental strengthening mechanisms responsible for these two types of size effect are to increase the resistanc...

  6. Modelling of Size Effect with Regularised Continua

    Directory of Open Access Journals (Sweden)

    H. Askes

    2004-01-01

    Full Text Available A nonlocal damage continuum and a viscoplastic damage continuum are used to model size effects. Three-point bending specimens are analysed, whereby a distinction is made between unnotched specimens, specimens with a constant notch and specimens with a proportionally scaled notch. Numerical finite element simulations have been performed for specimen sizes in a range of 1:64. Size effects are established in terms of nominal strength and compared to existing size effect models from the literature. 

  7. Size effects in manufacturing of metallic components

    DEFF Research Database (Denmark)

    Vollertsen, F; Biermann, D; Hansen, Hans Nørgaard

    2009-01-01

    In manufacturing of metallic components, the size of the part plays an important role for the process behaviour. This is due to so called size effects, which lead to changes in the process behaviour even if the relationship between the main geometrical features is kept constant. The aim...... of this paper is to give a systematic review on Such effects and their potential use or remedy. First, the typology of size effects will be explained, followed by a description of size effects on strength and tribology. The last three sections describe size effects on formability, forming processes and cutting...... processes. (C) 2009 CIRP....

  8. LS1 Report: Full-size security

    CERN Multimedia

    Anaïs Schaeffer

    2014-01-01

    Last week several CERN teams were involved in creating a life-size mock helium leak in Sector 4-5. The goals of the exercise were to measure how quickly the helium cloud spread, the change in temperature and the level of oxygen in various parts of the tunnel at different points in time, as well as to check the effects of the helium on the machine and the infrastructures and, above all, to re-evaluate the safety standards in force in the tunnel.   This photograph of the helium cloud was taken by the firemen during the third leak test. "The safety valves designed to release helium in the event of excess pressure are currently located within a 6-metre "no-stopping area" (3 metres on either side of the valves)," explains Johan Bremer of the TE-CRG group, who was in charge of the exercise. "People working in the tunnel can move through this area but are not authorised to stop. The idea is to avoid anyone being too close to the valves in the event of a l...

  9. On size effects in fracture

    International Nuclear Information System (INIS)

    Sinclair, G.B.

    1985-01-01

    This paper discusses the dependence of fracture stress on size. This conclusion is based on classical energy arguments. For an in-plane scaled specimen pair, the larger the specimen the smaller the fracture stress. In contrast the same theory gives a different dependence for out-of-plane specimen and the dependence involves plane stress, strain, fracture stresses and Poisson's ratio. The objective of this paper is to examine how well these predictions are actually complied with

  10. Do class size effects differ across grades?

    DEFF Research Database (Denmark)

    Nandrup, Anne Brink

    size cap that creates exogenous variation in class sizes. Significant (albeit modest) negative effects of class size increases are found for children on primary school levels. The effects on math abilities are statistically different across primary and secondary school. Larger classes do not affect......This paper contributes to the class size literature by analyzing whether short-run class size effects are constant across grade levels in compulsory school. Results are based on administrative data on all pupils enroled in Danish public schools. Identification is based on a government-imposed class...

  11. Do Class Size Effects Differ across Grades?

    Science.gov (United States)

    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…

  12. Prevention of the Portion Size Effect

    NARCIS (Netherlands)

    I. Versluis (Iris)

    2016-01-01

    markdownabstractAn increase in the portion size leads to an increase in energy intake, a phenomenon which is also referred to as the portion size effect. The increase in portion sizes in recent years is regarded as an important contributor to the increase in the prevalence of obesity. Hence, the aim

  13. BIG SCHOOL - SMALL SCHOOL. STUDIES OF THE EFFECTS OF HIGH SCHOOL SIZE UPON THE BEHAVIOR AND EXPERIENCES OF STUDENTS. FINAL REPORT.

    Science.gov (United States)

    BARKER, ROGER G.; AND OTHERS

    STUDIES WERE MADE IN KANSAS HIGH SCHOOLS TO DETERMINE THE EFFECT OF SCHOOL SIZE UPON THE BEHAVIOR AND EXPERIENCES OF STUDENTS. THE FOLLOWING AREAS WERE CONSIDERED-- THE SCHOOL INVOLVED IN THE STUDY, THE DATA GATHERED FROM RECORDS AND RESEARCH, OUT-OF-SCHOOL ACTIVITIES, AND THE PLACE OF HIGH SCHOOL STUDENTS IN THE TOTAL LIFE OF FOUR SMALL TOWNS.…

  14. An Exploratory Study of the Effect of Screen Size and Resolution on the Legibility of Graphics in Automated Job Performance Aids. Final Report.

    Science.gov (United States)

    Dwyer, Daniel J.

    Designed to assess the effect of alternative display (CRT) screen sizes and resolution levels on user ability to identify and locate printed circuit (PC) board points, this study is the first in a protracted research program on the legibility of graphics in computer-based job aids. Air Force maintenance training pipeline students (35 male and 1…

  15. Size effects in thin films

    CERN Document Server

    Tellier, CR; Siddall, G

    1982-01-01

    A complete and comprehensive study of transport phenomena in thin continuous metal films, this book reviews work carried out on external-surface and grain-boundary electron scattering and proposes new theoretical equations for transport properties of these films. It presents a complete theoretical view of the field, and considers imperfection and impurity effects.

  16. Biofuel manufacturing from woody biomass: effects of sieve size used in biomass size reduction.

    Science.gov (United States)

    Zhang, Meng; Song, Xiaoxu; Deines, T W; Pei, Z J; Wang, Donghai

    2012-01-01

    Size reduction is the first step for manufacturing biofuels from woody biomass. It is usually performed using milling machines and the particle size is controlled by the size of the sieve installed on a milling machine. There are reported studies about the effects of sieve size on energy consumption in milling of woody biomass. These studies show that energy consumption increased dramatically as sieve size became smaller. However, in these studies, the sugar yield (proportional to biofuel yield) in hydrolysis of the milled woody biomass was not measured. The lack of comprehensive studies about the effects of sieve size on energy consumption in biomass milling and sugar yield in hydrolysis process makes it difficult to decide which sieve size should be selected in order to minimize the energy consumption in size reduction and maximize the sugar yield in hydrolysis. The purpose of this paper is to fill this gap in the literature. In this paper, knife milling of poplar wood was conducted using sieves of three sizes (1, 2, and 4 mm). Results show that, as sieve size increased, energy consumption in knife milling decreased and sugar yield in hydrolysis increased in the tested range of particle sizes.

  17. The relationship between UT reported size and actual size of the defects in rotor forgings

    International Nuclear Information System (INIS)

    Seong, Un Hak; Kim, Jeong Tae; Park, Yun Sik

    2003-01-01

    In order to evaluate the reliability of rotor forgings, it is very important to know the actual size of the defects in the rotor forgings. The determination of the defect size requires the accurate non-destructive measurement. However, there may be some differences between the reported size with the ultrasonic non-destructive testing method and the actual size of defects. These differences may be a severe cause of errors in evaluation of rotor forgings. So, the calculated size with 'Master Curve' considering safety factor, which is usually larger than the reported size, has been used in evaluation of rotor forgings. The relation between the EFBH (Equivalent Flat Bottom Hole) size measured by non-destructive method and the actual size by destructive method in many rotors manufactured at Doosan was investigated. In this investigation 'Master Curve' compensating the differences between UT reported size and actual size of defects in our rotor forgings was obtainable. The applicability of this 'Master Curve' as a way of calculating the actual defect size was also investigated. For the evaluation of rotor forgings, it is expected that this 'Master Curve' may be used to determine the accurate actual size of defects.

  18. The relationship between UT reported size and actual size of the defects in rotor forgings

    International Nuclear Information System (INIS)

    Seong, Un Hak; Kim, Jeong Tae; Park, Yun Sik

    2003-01-01

    In order to evaluate the reliability of rotor forgings, it is very important to know the actual size of the defects in the rotor forgings. The determination of the defect size requires the accurate non-destructive measurement. However, there may be some difference between the reported size with ultrasonic non-destructive testing method and the actual size of defects. These differences may be a severe cause of errors in evaluation of rotor forgings. So, the calculated size with 'Master Curve' considering safety factor, which is usually larger than the reported size, has been used in evaluation of rotor forgings. The relation between the EFBH (Equivalent Flat Bottom Hole) size measured by non-destructive method and the actual size by destructive method in many rotors manufactured at Doosan was investigated. In this investigation, 'Master Curve' compensating the differences between UT reported size and actual size of defects in our rotor forgings was obtainable. The applicability of this 'Master Curve' as a way of calculating the actual defect size was also investigated. For the evaluation of rotor forgings, it is expected that this 'Master Curve' may be used to determine the accurate actual size of defects.

  19. EFFECTS OF EFFECTS OF PARTICLE SIZE DISTRIBUTION ...

    African Journals Online (AJOL)

    eobe

    The parameters examined were: moisture content, particle size distribution, total isture content, particle size distribution, total hydrocarbon content, soil pH, available nitrogen, available phosphorus, total heterotrophic bacteria and fungi count. The analysis of the soil characteristics throughout the remediation period showed ...

  20. Structural effect of size on interracial friendship.

    Science.gov (United States)

    Cheng, Siwei; Xie, Yu

    2013-04-30

    Social contexts exert structural effects on individuals' social relationships, including interracial friendships. In this study, we posit that, net of group composition, total context size has a distinct effect on interracial friendship. Under the assumptions of (i) maximization of preference in choosing a friend, (ii) multidimensionality of preference, and (iii) preference for same-race friends, we conducted analyses using microsimulation that yielded three main findings. First, increased context size decreases the likelihood of forming an interracial friendship. Second, the size effect increases with the number of preference dimensions. Third, the size effect is diluted by noise, i.e., the random component affecting friendship formation. Analysis of actual friendship data among 4,745 American high school students yielded results consistent with the main conclusion that increased context size promotes racial segregation and discourages interracial friendship.

  1. Nanocoatings size effect in nanostructured films

    CERN Document Server

    Aliofkhazraei, Mahmood

    2014-01-01

    Size effect in structures has been taken into consideration over the last years. In comparison with coatings with micrometer-ranged thickness, nanostructured coatings usually enjoy better and appropriate properties, such as strength and resistance. These coatings enjoy unique magnetic properties and are used with the aim of producing surfaces resistant against erosion, lubricant system, cutting tools, manufacturing hardened sporadic alloys, being resistant against oxidation and corrosion. This book reviews researches on fabrication and classification of nanostructured coatings with focus on size effect in nanometric scale. Size effect on electrochemical, mechanical and physical properties of nanocoatings are presented.

  2. Effect of display size on visual attention.

    Science.gov (United States)

    Chen, I-Ping; Liao, Chia-Ning; Yeh, Shih-Hao

    2011-06-01

    Attention plays an important role in the design of human-machine interfaces. However, current knowledge about attention is largely based on data obtained when using devices of moderate display size. With advancement in display technology comes the need for understanding attention behavior over a wider range of viewing sizes. The effect of display size on test participants' visual search performance was studied. The participants (N = 12) performed two types of visual search tasks, that is, parallel and serial search, under three display-size conditions (16 degrees, 32 degrees, and 60 degrees). Serial, but not parallel, search was affected by display size. In the serial task, mean reaction time for detecting a target increased with the display size.

  3. Disruption effects on the beam size measurement

    International Nuclear Information System (INIS)

    Raimondi, P.; Decker, F.J.; Chen, P.

    1995-01-01

    At the SLC Final Focus with higher currents and smaller beam sizes, the disruption parameter D y is close to one and so the pinch effect should produce a luminosity enhancement. Since a flat beam-beam function is fit to deflection scan data to measure the beam size, disruption can affect the measurement. Here the authors discuss the quantitative effects of disruption for typical SLC beam parameters. With 3.5 10 10 particles per pulse, bunch length of 0.8 mm and beam sizes of 2.1 μm horizontally and 0.55 μm vertically, the measured vertical size can be as much as 25% bigger than the real one. Furthermore during the collision the spot size actually decrease, producing an enhancement factor H D of about 1.25. This would yield to a true luminosity which is 1.6 times that which is estimated from the beam-beam deflection fit

  4. FIRM SIZE EFFECTS ON TRANSACTION COSTS

    NARCIS (Netherlands)

    NOOTEBOOM, B

    1993-01-01

    Associated with effects of scale, scope, experience and learning there are effects of firm size on transaction costs; in the stages of contact, contract and control. These effects are due to ''threshold costs'' in setting up contacts, contracts and governance schemes, and to differences with respect

  5. Computation of Effect Size for Moderating Effects of Categorical Variables in Multiple Regression

    Science.gov (United States)

    Aguinis, Herman; Pierce, Charles A.

    2006-01-01

    The computation and reporting of effect size estimates is becoming the norm in many journals in psychology and related disciplines. Despite the increased importance of effect sizes, researchers may not report them or may report inaccurate values because of a lack of appropriate computational tools. For instance, Pierce, Block, and Aguinis (2004)…

  6. Development of neural basis for chinese orthographic neighborhood size effect.

    Science.gov (United States)

    Zhao, Jing; Li, Qing-Lin; Ding, Guo-Sheng; Bi, Hong-Yan

    2016-02-01

    The brain activity of orthographic neighborhood size (N size) effect in Chinese character naming has been studied in adults, meanwhile behavioral studies have revealed a developmental trend of Chinese N-size effect in developing readers. However, it is unclear whether and how the neural mechanism of N-size effect changes in Chinese children along with development. Here we address this issue using functional magnetic resonance imaging. Forty-four students from the 3(rd) , 5(th) , and 7(th) grades were scanned during silent naming of Chinese characters. After scanning, all participants took part in an overt naming test outside the scanner, and results of the naming task showed that the 3(rd) graders named characters from large neighborhoods faster than those from small neighborhoods, revealing a facilitatory N-size effect; the 5(th) graders showed null N-size effect while the 7(th) graders showed an inhibitory N-size effect. Neuroimaging results revealed that only the 3(rd) graders exhibited a significant N-size effect in the left middle occipital activity, with greater activation for large N-size characters. Results of 5(th) and 7(th) graders showed significant N-size effects in the left middle frontal gyrus, in which 5(th) graders induced greater activation in large N-size condition than in small N-size condition, while 7(th) graders exhibited an opposite effect which was similar to the adult pattern reported in a previous study. The current findings suggested the transition from broadly tuned to finely tuned orthographic representation with reading development, and the inhibition from neighbors' phonology for higher graders. Hum Brain Mapp 37:632-647, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  7. Measuring wage effects of plant size

    DEFF Research Database (Denmark)

    Albæk, Karsten; Arai, Mahmood; Asplund, Rita

    1998-01-01

    There are large plant size–wage effects in the Nordic countries after taking into account individual and job characteristics as well as systematical sorting of the workers into various plant-sizes. The plant size–wage elasticities we obtain are, in contrast to other dimensions of the wage distrib......–wage elasticity. Our results indicate that using size–class midpoints yields essentially the same results as using exact measures of plant size...

  8. Specimen size effects in Charpy impact testing

    International Nuclear Information System (INIS)

    Alexander, D.J.; Klueh, R.L.

    1989-01-01

    Full-size , half-size, and third-size specimens from several different steels have been tested as part of an ongoing alloy development program. The smaller specimens permit more specimens to be made from small trail heats and are much more efficient for irradiation experiments. The results of several comparisons between the different specimen sizes have shown that the smaller specimens show qualitatively similar behavior to large specimens, although the upper-shelf energy level and ductile-to-ductile transition temperature are reduced. The upper-shelf energy levels from different specimen sizes can be compared by using a simple volume normalization method. The effect of specimen size and geometry on the ductile-to-ductile transition temperature is more difficult to predict, although the available data suggest a simple shift in the transition temperature due to specimen size changes.The relatively shallower notch used in smaller specimens alters the deformation pattern, and permits yielding to spread back to the notched surface as well as through to the back. This reduces the constraint and the peak stresses, and thus the initiation of cleavage is more difficult. A better understanding of the stress and strain distributions is needed. 19 refs., 3 figs., 3 tabs

  9. Portion size and intended consumption. Evidence for a pre-consumption portion size effect in males?

    Science.gov (United States)

    Robinson, Eric; te Raa, Wesselien; Hardman, Charlotte A

    2015-08-01

    Larger portions increase energy intake (the 'portion size effect'); however, the mechanisms behind this effect are unclear. Although pre-meal intentions are thought to be an important determinant of energy intake, little research has examined how much of a meal individuals intend to eat when served standard versus larger portion sizes. Three studies examined the effect of manipulating portion size on intended food consumption. In Studies 1 (spaghetti bolognese) and 2 (curry and rice) male participants were shown an image of either a standard or a larger meal and indicated how much of the meal they intended to consume. In Study 3 male and female participants were served either a standard or a larger portion of ice cream for dessert, they indicated how much they intended to consume and then ate as much of the ice cream as they desired. Regardless of being shown standard or large portion sizes, in Studies 1 and 2 participants reported that they intended to eat the majority of the meal, equating to a large difference in intended energy consumption between portion size conditions (a 'pre-consumption portion size effect'). This finding was replicated in male participants in Study 3, although females intended to eat a smaller proportion of the larger portion of ice cream, compared to the standard portion. Both male and female participants tended to eat in accordance with their pre-meal intentions and a portion size effect on actual consumption was subsequently observed in males, but not in females. The portion size effect may be observed when measuring pre-meal intended consumption in males. Copyright © 2015. Published by Elsevier Ltd.

  10. Disruption effects on the beam size measurement

    Energy Technology Data Exchange (ETDEWEB)

    Raimondi, P.; Decker, F.J.; Chen, P.

    1995-06-01

    At the SLC Final Focus with higher currents and smaller beam sizes, the disruption parameter D{sub y} is close to one and so the pinch effect should produce a luminosity enhancement. Since a flat beam-beam function is fit to deflection scan data to measure the beam size, disruption can affect the measurement. Here the authors discuss the quantitative effects of disruption for typical SLC beam parameters. With 3.5 10{sup 10} particles per pulse, bunch length of 0.8 mm and beam sizes of 2.1 {mu}m horizontally and 0.55 {mu}m vertically, the measured vertical size can be as much as 25% bigger than the real one. Furthermore during the collision the spot size actually decrease, producing an enhancement factor H{sub D} of about 1.25. This would yield to a true luminosity which is 1.6 times that which is estimated from the beam-beam deflection fit.

  11. Introducing the Mean Absolute Deviation "Effect" Size

    Science.gov (United States)

    Gorard, Stephen

    2015-01-01

    This paper revisits the use of effect sizes in the analysis of experimental and similar results, and reminds readers of the relative advantages of the mean absolute deviation as a measure of variation, as opposed to the more complex standard deviation. The mean absolute deviation is easier to use and understand, and more tolerant of extreme…

  12. Size Effect in Tension Perpendicular to Grain

    DEFF Research Database (Denmark)

    Astrup, Thomas; Clorius, Christian Odin; Hoffmeyer, Preben

    2004-01-01

    The strength of wood is reduced when the stressed volume is increased. The phenomenon is termed size effect and is often explained as being stochastic in the sense that the probability of weak locations occurring in the wood increases with increased volume. This paper presents a hypothesis where ...

  13. Size-effects in porous metals

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    The intrinsic size-effect for porous metals is investigated. The analyses are carried out numerically using a finite strain generalization of a higher order strain gradient plasticity model. Results for plane strain growth of cylindrical voids are presented in terms of response curves and curves...

  14. Size-effects in porous metals

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2007-01-01

    The intrinsic size-effect for porous metals is investigated. The analyses are carried out numerically using a finite strain generalization of a higher order strain gradient plasticity model. Results for plane strain growth of cylindrical voids are presented in terms of response curves and curves...

  15. Size effects in lithium ion batteries

    International Nuclear Information System (INIS)

    Yao Hu-Rong; Yin Ya-Xia; Guo Yu-Gao

    2016-01-01

    Size-related properties of novel lithium battery materials, arising from kinetics, thermodynamics, and newly discovered lithium storage mechanisms, are reviewed. Complementary experimental and computational investigations of the use of the size effects to modify electrodes and electrolytes for lithium ion batteries are enumerated and discussed together. Size differences in the materials in lithium ion batteries lead to a variety of exciting phenomena. Smaller-particle materials with highly connective interfaces and reduced diffusion paths exhibit higher rate performance than the corresponding bulk materials. The thermodynamics is also changed by the higher surface energy of smaller particles, affecting, for example, secondary surface reactions, lattice parameter, voltage, and the phase transformation mechanism. Newly discovered lithium storage mechanisms that result in superior storage capacity are also briefly highlighted. (topical review)

  16. Origin of size effect on efficiency of organic photovoltaics

    DEFF Research Database (Denmark)

    Manor, Assaf; Katz, Eugene A.; Tromholt, Thomas

    2011-01-01

    It is widely accepted that efficiency of organic solar cells could be limited by their size. However, the published data on this effect are very limited and none of them includes analysis of light intensity dependence of the key cell parameters. We report such analysis for bulk heterojunction sol...

  17. Normal-sized ovarian papillary serous carcinoma: a case report.

    Science.gov (United States)

    Wu, W C; Lai, C I; Huang, L C; Chiu, T H; Hung, Y C; Chang, W C

    2010-01-01

    A normal-sized ovarian papillary serous carcinoma is rare. We present the case of a 46-year-old woman with progressive abdominal fullness of one week's duration. The medical evaluation revealed abdominal carcinomatosis with normal-sized ovaries and an elevated serum CA-125 level of 147,365.8 U/ml. Cytoreductive surgery (hysterectomy, bilateral salpingo-oophorectomy, omentectomy, lymphadenectomy, infracolic omentectomy, peritoneal biopsy, washing cytology, and appendectomy) was performed. The histologic examination revealed an ovarian serous papillary carcinoma. Adjuvant chemotherapy was administered. The serum CA-125 level decreased after completion of treatment. Normal-sized ovarian serous surface papillary carcinomas should be kept in mind as an origin of disease in patients who have peritoneal carcinomatosis, which sometimes is a diagnostic dilemma of the disease source. We report this case to emphasize the clinical symptoms and importance of the early and accurate diagnosis of a normal-sized ovarian papillary serous carcinoma.

  18. Interviewer Effects on a Network-Size Filter Question

    Directory of Open Access Journals (Sweden)

    Josten Michael

    2016-06-01

    Full Text Available There is evidence that survey interviewers may be tempted to manipulate answers to filter questions in a way that minimizes the number of follow-up questions. This becomes relevant when ego-centered network data are collected. The reported network size has a huge impact on interview duration if multiple questions on each alter are triggered. We analyze interviewer effects on a network-size question in the mixed-mode survey “Panel Study ‘Labour Market and Social Security’” (PASS, where interviewers could skip up to 15 follow-up questions by generating small networks. Applying multilevel models, we find almost no interviewer effects in CATI mode, where interviewers are paid by the hour and frequently supervised. In CAPI, however, where interviewers are paid by case and no close supervision is possible, we find strong interviewer effects on network size. As the area-specific network size is known from telephone mode, where allocation to interviewers is random, interviewer and area effects can be separated. Furthermore, a difference-in-difference analysis reveals the negative effect of introducing the follow-up questions in Wave 3 on CAPI network size. Attempting to explain interviewer effects we neither find significant main effects of experience within a wave, nor significantly different slopes between interviewers.

  19. Size-Effects in Void Growth

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof

    2005-01-01

    The size-effect on ductile void growth in metals is investigated. The analysis is based on unit cell models both of arrays of cylindrical voids under plane strain deformation, as well as arrays of spherical voids using an axisymmetric model. A recent finite strain generalization of two higher order...... strain gradient plasticity models is implemented in a finite element program, which is used to study void growth numerically. The results based on the two models are compared. It is shown how gradient effects suppress void growth on the micron scale when compared to predictions based on conventional...... models. This increased resistance to void growth, due to gradient hardening, is accompanied by an increase in the overall strength for the material. Furthermore, for increasing initial void volume fraction, it is shown that the effect of gradients becomes more important to the overall response but less...

  20. The pack size effect: Influence on consumer perceptions of portion sizes

    NARCIS (Netherlands)

    Hieke, Sophie; Palascha, Aikaterini; Jola, Corinne; Wills, Josephine; Raats, Monique M.

    2016-01-01

    Larger portions as well as larger packs can lead to larger prospective consumption estimates, larger servings and increased consumption, described as 'portion-size effects' and 'pack size effects'. Although related, the effects of pack sizes on portion estimates have received less attention. While

  1. Particle sizing experiments with the laser Doppler velocimeter: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Giel, T.V. Jr.; Son, J.Y.

    1988-06-01

    Measurement techniques for in-situ simultaneous measurements of particle size distributions and particle velocities using the dual beam laser Doppler velocimeter (LV) were analytically and experimentally investigated. This investigation examined the different signal characteristics of the LV for determination of particle size and particle velocity, simultaneously. The different size related signal components were evaluated not only singularly but also as simultaneous measurements to determine which characteristic, or combination of characteristics, provided the best measure of particle size. The evaluation concentrated on the 0.5 to 5 ..mu..m particle size range, in which the LV light scattering characteristics are complex often non-monotonic functions of the particle size as well as functions of index of refraction, the laser light wavelength, laser intensity and polarization, and the location and response characteristics of the detector. Different components of the LV signal were considered, but analysis concentrated on Doppler phase, visibility and scatter-intensity because they show the greatest promise. These signals characteristics were initially defined analytically for numerous optical configurations over the 0.5 to 5 ..mu..m diameter range with 0.1 ..mu..m segmentation, for refractive index values from 1.0 to 3.0 with absorptive (imaginary) components varied form 0 to 1.0. Collector orientation and effective f/No., as well as fringe spacing, beam polarization and wavelength, were varied in this analytical evaluation. 18 refs., 42 figs., 5 tabs.

  2. JAIF report on small- and medium-size LWRs

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    The Ministry of International Trade and Industry has made a report on the results of the study on the utilization of small and medium size LWRs. The Japan Atomic Industrial Forum undertook this research work by the commission of the Ministry. It studied six cases of PWRs and BWRs with thermal output power ranging from 20 MWt to 700 MWt as the hypothetical design for their siting conditions, reactor capacity and the examples of utilization of the corresponding steam output. A large housing estate of 5,000 units, a local core city with population of 100,000, industrial utilization for petrochemical plants and paper and pulp plants and the combined utilization for a factory and a housing estate of 5,000 units were examined. The report said that a city with population of 100,000 would be the best object to supply heat from a nuclear reactor, and it is important to develop the nuclear reactors with 200 MWt capacity. This type is versatile in the siting conditions, and can be constructed near a city, accordingly, it offers the possibility of extensive utilization. The significance of small and medium size LWRs as the alternative energy for oil, the regional development accompanying the use of small and medium size LWRs, the technical development toward scale reduction, easy operation and versatile utilization, the economical evaluation of the utilization models and the tasks for the future are reported. (Kako, I.)

  3. An Effect Size Measure for Raju's Differential Functioning for Items and Tests

    Science.gov (United States)

    Wright, Keith D.; Oshima, T. C.

    2015-01-01

    This study established an effect size measure for differential functioning for items and tests' noncompensatory differential item functioning (NCDIF). The Mantel-Haenszel parameter served as the benchmark for developing NCDIF's effect size measure for reporting moderate and large differential item functioning in test items. The effect size of…

  4. Size effects in ductile cellular solids. Part I : modeling

    NARCIS (Netherlands)

    Onck, P.R.; Andrews, E.W.; Gibson, L.J.

    2001-01-01

    In the mechanical testing of metallic foams, an important issue is the effect of the specimen size, relative to the cell size, on the measured properties. Here we analyze size effects for the modulus and strength of regular, hexagonal honeycombs under uniaxial and shear loadings. Size effects for

  5. Size effects in foams : Experiments and modeling

    NARCIS (Netherlands)

    Tekoglu, C.; Gibson, L. J.; Pardoen, T.; Onck, P. R.

    Mechanical properties of cellular solids depend on the ratio of the sample size to the cell size at length scales where the two are of the same order of magnitude. Considering that the cell size of many cellular solids used in engineering applications is between 1 and 10 mm, it is not uncommon to

  6. Board Size Effects in Closely Held Corporations

    DEFF Research Database (Denmark)

    Bennedsen, Morten; Kongsted, H.C.; Meisner Nielsen, Kasper

    2004-01-01

    of board size by using a new instrument given bythe number of children of the founders of the firms. Our analysis shows thatboard size can be taken as exogenous in the performance equation. Furthermore,based on a flexible model specification we find that there is noempirical evidence of adverse board size...

  7. The P Value Problem in Otolaryngology: Shifting to Effect Sizes and Confidence Intervals.

    Science.gov (United States)

    Vila, Peter M; Townsend, Melanie Elizabeth; Bhatt, Neel K; Kao, W Katherine; Sinha, Parul; Neely, J Gail

    2017-06-01

    There is a lack of reporting effect sizes and confidence intervals in the current biomedical literature. The objective of this article is to present a discussion of the recent paradigm shift encouraging the use of reporting effect sizes and confidence intervals. Although P values help to inform us about whether an effect exists due to chance, effect sizes inform us about the magnitude of the effect (clinical significance), and confidence intervals inform us about the range of plausible estimates for the general population mean (precision). Reporting effect sizes and confidence intervals is a necessary addition to the biomedical literature, and these concepts are reviewed in this article.

  8. Effects of Seed Size on Germination and Early Morphorlogical and ...

    African Journals Online (AJOL)

    Effects of Seed Size on Germination and Early Morphorlogical and Physiological Characteristics of Gmelina Arborea , Roxb. ... African Research Review ... They were grouped into 3 categories as large seed size (LSS), medium seed size ...

  9. Intermediate-Size Inducer Pump design report. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Boardman, T.J.

    1979-06-15

    This report summarizes the mechanical, structural, and hydrodynamic design of the Intermediate-Size Inducer Pump (ISIP). The design was performed under Atomics International's DOE Base Technology Program by the Atomics International and Rocketdyne Divisions of Rockwell International. The pump was designed to utilize the FFTF prototype pump frame as a test vehicle to test the inducer, impeller, and diffuser plus necessary adapter hardware under simulated Large Scale Liquid Metal Fast Breeder Reactor service conditions. The report describes the design requirements including the purpose and objectives, and discusses those design efforts and considerations made to meet the requirements. Included in the report are appendices showing calculative methods and results. Also included are overall assembly and layout drawings plus some details used as illustrations for discussion of the design results and the results of water tests performed on a model of the inducer.

  10. Effects of portion size on chronic energy intake

    Directory of Open Access Journals (Sweden)

    Pentel Paul R

    2007-06-01

    Full Text Available Abstract Background This study experimentally examined the effects of repeated exposure to different meal portion sizes on energy intake. Methods Nineteen employees of a county medical center were given free box lunches for two months, one month each of 1528 and 767 average kcal. Foods were identical in the two conditions, but differed in portion size. Meals averaged 44% calories from fat. Participants self-reported how much of each lunch was eaten. Unannounced 24-hour dietary recalls were also conducted by phone twice per week during each exposure period. Results Mean energy intake at the lunch meal was 332 kcal/day higher in large lunch than in small lunch periods (p Conclusion This study suggests that chronic exposure to large portion size meals can result in sustained increases in energy intake and may contribute to body weight increases over time.

  11. Effect size, confidence intervals and statistical power in psychological research.

    Directory of Open Access Journals (Sweden)

    Téllez A.

    2015-07-01

    Full Text Available Quantitative psychological research is focused on detecting the occurrence of certain population phenomena by analyzing data from a sample, and statistics is a particularly helpful mathematical tool that is used by researchers to evaluate hypotheses and make decisions to accept or reject such hypotheses. In this paper, the various statistical tools in psychological research are reviewed. The limitations of null hypothesis significance testing (NHST and the advantages of using effect size and its respective confidence intervals are explained, as the latter two measurements can provide important information about the results of a study. These measurements also can facilitate data interpretation and easily detect trivial effects, enabling researchers to make decisions in a more clinically relevant fashion. Moreover, it is recommended to establish an appropriate sample size by calculating the optimum statistical power at the moment that the research is designed. Psychological journal editors are encouraged to follow APA recommendations strictly and ask authors of original research studies to report the effect size, its confidence intervals, statistical power and, when required, any measure of clinical significance. Additionally, we must account for the teaching of statistics at the graduate level. At that level, students do not receive sufficient information concerning the importance of using different types of effect sizes and their confidence intervals according to the different types of research designs; instead, most of the information is focused on the various tools of NHST.

  12. Optimizing the maximum reported cluster size in the spatial scan statistic for ordinal data.

    Science.gov (United States)

    Kim, Sehwi; Jung, Inkyung

    2017-01-01

    The spatial scan statistic is an important tool for spatial cluster detection. There have been numerous studies on scanning window shapes. However, little research has been done on the maximum scanning window size or maximum reported cluster size. Recently, Han et al. proposed to use the Gini coefficient to optimize the maximum reported cluster size. However, the method has been developed and evaluated only for the Poisson model. We adopt the Gini coefficient to be applicable to the spatial scan statistic for ordinal data to determine the optimal maximum reported cluster size. Through a simulation study and application to a real data example, we evaluate the performance of the proposed approach. With some sophisticated modification, the Gini coefficient can be effectively employed for the ordinal model. The Gini coefficient most often picked the optimal maximum reported cluster sizes that were the same as or smaller than the true cluster sizes with very high accuracy. It seems that we can obtain a more refined collection of clusters by using the Gini coefficient. The Gini coefficient developed specifically for the ordinal model can be useful for optimizing the maximum reported cluster size for ordinal data and helpful for properly and informatively discovering cluster patterns.

  13. Modelling the effect of size-asymmetric competition on size inequality

    DEFF Research Database (Denmark)

    Rasmussen, Camilla Ruø; Weiner, Jacob

    2017-01-01

    Abstract The concept of size asymmetry in resource competition among plants, in which larger individuals obtain a disproportionate share of contested resources, appears to be very straightforward, but the effects of size asymmetry on growth and size variation among individuals have proved...... to be controversial. It has often been assumed that competition among individual plants in a population has to be size-asymmetric to result in higher size inequality than in the absence of competition, but here we question this inference. Using very simple, individual-based models, we investigate how size symmetry...... of competition affects the development in size inequality between two competing plants and show that increased size inequality due to competition is not always strong evidence for size-asymmetric competition. Even absolute symmetric competition, in which all plants receive the same amount of resources...

  14. [Effect sizes, statistical power and sample sizes in "the Japanese Journal of Psychology"].

    Science.gov (United States)

    Suzukawa, Yumi; Toyoda, Hideki

    2012-04-01

    This study analyzed the statistical power of research studies published in the "Japanese Journal of Psychology" in 2008 and 2009. Sample effect sizes and sample statistical powers were calculated for each statistical test and analyzed with respect to the analytical methods and the fields of the studies. The results show that in the fields like perception, cognition or learning, the effect sizes were relatively large, although the sample sizes were small. At the same time, because of the small sample sizes, some meaningful effects could not be detected. In the other fields, because of the large sample sizes, meaningless effects could be detected. This implies that researchers who could not get large enough effect sizes would use larger samples to obtain significant results.

  15. Strong crystal size effect on deformation twinning

    DEFF Research Database (Denmark)

    Yu, Qian; Shan, Zhi-Wei; Li, Ju

    2010-01-01

    plasticity. Accompanying the transition in deformation mechanism, the maximum flow stress of the submicrometre-sized pillars was observed to saturate at a value close to titanium’s ideal strength9, 10. We develop a ‘stimulated slip’ model to explain the strong size dependence of deformation twinning......Deformation twinning1, 2, 3, 4, 5, 6 in crystals is a highly coherent inelastic shearing process that controls the mechanical behaviour of many materials, but its origin and spatio-temporal features are shrouded in mystery. Using micro-compression and in situ nano-compression experiments, here we...... find that the stress required for deformation twinning increases drastically with decreasing sample size of a titanium alloy single crystal7, 8, until the sample size is reduced to one micrometre, below which the deformation twinning is entirely replaced by less correlated, ordinary dislocation...

  16. Size effect in the strength of concrete structures

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    The fracture mechanics size effect, as opposed to the Weibull statistical size effect, is a .... Solutions for TPB beam and a typical wedge-splitting geometry have been ..... Bazant Z P 1984 Size effect in blunt fracture: Concrete, rock, metal. J. Eng.

  17. The causal effect of board size in the performance of small and medium-sized firms

    DEFF Research Database (Denmark)

    Bennedsen, Morten; Kongsted, Hans Christian; Meisner Nielsen, Kasper

    2008-01-01

    correlation between family size and board size and show this correlation to be driven by firms where the CEO's relatives serve on the board. Second, we find empirical evidence of a small adverse board size effect driven by the minority of small and medium-sized firms that are characterized by having......Empirical studies of large publicly traded firms have shown a robust negative relationship between board size and firm performance. The evidence on small and medium-sized firms is less clear; we show that existing work has been incomplete in analyzing the causal relationship due to weak...... identification strategies. Using a rich data set of almost 7000 closely held corporations we provide a causal analysis of board size effects on firm performance: We use a novel instrument given by the number of children of the chief executive officer (CEO) of the firms. First, we find a strong positive...

  18. Characterization of resonances using finite size effects

    International Nuclear Information System (INIS)

    Pozsgay, B.; Takacs, G.

    2006-01-01

    We develop methods to extract resonance widths from finite volume spectra of (1+1)-dimensional quantum field theories. Our two methods are based on Luscher's description of finite size corrections, and are dubbed the Breit-Wigner and the improved ''mini-Hamiltonian'' method, respectively. We establish a consistent framework for the finite volume description of sufficiently narrow resonances that takes into account the finite size corrections and mass shifts properly. Using predictions from form factor perturbation theory, we test the two methods against finite size data from truncated conformal space approach, and find excellent agreement which confirms both the theoretical framework and the numerical validity of the methods. Although our investigation is carried out in 1+1 dimensions, the extension to physical 3+1 space-time dimensions appears straightforward, given sufficiently accurate finite volume spectra

  19. Causality in Statistical Power: Isomorphic Properties of Measurement, Research Design, Effect Size, and Sample Size

    Directory of Open Access Journals (Sweden)

    R. Eric Heidel

    2016-01-01

    Full Text Available Statistical power is the ability to detect a significant effect, given that the effect actually exists in a population. Like most statistical concepts, statistical power tends to induce cognitive dissonance in hepatology researchers. However, planning for statistical power by an a priori sample size calculation is of paramount importance when designing a research study. There are five specific empirical components that make up an a priori sample size calculation: the scale of measurement of the outcome, the research design, the magnitude of the effect size, the variance of the effect size, and the sample size. A framework grounded in the phenomenon of isomorphism, or interdependencies amongst different constructs with similar forms, will be presented to understand the isomorphic effects of decisions made on each of the five aforementioned components of statistical power.

  20. Effect Size Analyses of Souvenaid in Patients with Alzheimer's Disease.

    Science.gov (United States)

    Cummings, Jeffrey; Scheltens, Philip; McKeith, Ian; Blesa, Rafael; Harrison, John E; Bertolucci, Paulo H F; Rockwood, Kenneth; Wilkinson, David; Wijker, Wouter; Bennett, David A; Shah, Raj C

    2017-01-01

    Souvenaid® (uridine monophosphate, docosahexaenoic acid, eicosapentaenoic acid, choline, phospholipids, folic acid, vitamins B12, B6, C, and E, and selenium), was developed to support the formation and function of neuronal membranes. To determine effect sizes observed in clinical trials of Souvenaid and to calculate the number needed to treat to show benefit or harm. Data from all three reported randomized controlled trials of Souvenaid in Alzheimer's disease (AD) dementia (Souvenir I, Souvenir II, and S-Connect) and an open-label extension study were included in analyses of effect size for cognitive, functional, and behavioral outcomes. Effect size was determined by calculating Cohen's d statistic (or Cramér's V method for nominal data), number needed to treat and number needed to harm. Statistical calculations were performed for the intent-to-treat populations. In patients with mild AD, effect sizes were 0.21 (95% confidence intervals: -0.06, 0.49) for the primary outcome in Souvenir II (neuropsychological test battery memory z-score) and 0.20 (0.10, 0.34) for the co-primary outcome of Souvenir I (Wechsler memory scale delayed recall). No effect was shown on cognition in patients with mild-to-moderate AD (S-Connect). The number needed to treat (6 and 21 for Souvenir I and II, respectively) and high number needed to harm values indicate a favorable harm:benefit ratio for Souvenaid versus control in patients with mild AD. The favorable safety profile and impact on outcome measures converge to corroborate the putative mode of action and demonstrate that Souvenaid can achieve clinically detectable effects in patients with early AD.

  1. Does length or neighborhood size cause the word length effect?

    Science.gov (United States)

    Jalbert, Annie; Neath, Ian; Surprenant, Aimée M

    2011-10-01

    Jalbert, Neath, Bireta, and Surprenant (2011) suggested that past demonstrations of the word length effect, the finding that words with fewer syllables are recalled better than words with more syllables, included a confound: The short words had more orthographic neighbors than the long words. The experiments reported here test two predictions that would follow if neighborhood size is a more important factor than word length. In Experiment 1, we found that concurrent articulation removed the effect of neighborhood size, just as it removes the effect of word length. Experiment 2 demonstrated that this pattern is also found with nonwords. For Experiment 3, we factorially manipulated length and neighborhood size, and found only effects of the latter. These results are problematic for any theory of memory that includes decay offset by rehearsal, but they are consistent with accounts that include a redintegrative stage that is susceptible to disruption by noise. The results also confirm the importance of lexical and linguistic factors on memory tasks thought to tap short-term memory.

  2. Effects of sample size on the second magnetization peak in ...

    Indian Academy of Sciences (India)

    the sample size decreases – a result that could be interpreted as a size effect in the order– disorder vortex matter phase transition. However, local magnetic measurements trace this effect to metastable disordered vortex states, revealing the same order–disorder transition induction in samples of different size. Keywords.

  3. Effectiveness of the Size Matters Handwriting Program.

    Science.gov (United States)

    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.

  4. Simulation of finite size effects of the fiber bundle model

    Science.gov (United States)

    Hao, Da-Peng; Tang, Gang; Xun, Zhi-Peng; Xia, Hui; Han, Kui

    2018-01-01

    In theory, the macroscopic fracture of materials should correspond with the thermodynamic limit of the fiber bundle model. However, the simulation of a fiber bundle model with an infinite size is unrealistic. To study the finite size effects of the fiber bundle model, fiber bundle models of various size are simulated in detail. The effects of system size on the constitutive behavior, critical stress, maximum avalanche size, avalanche size distribution, and increased step number of external load are explored. The simulation results imply that there is no feature size or cut size for macroscopic mechanical and statistical properties of the model. The constitutive curves near the macroscopic failure for various system size can collapse well with a simple scaling relationship. Simultaneously, the introduction of a simple extrapolation method facilitates the acquisition of more accurate simulation results in a large-limit system, which is better for comparison with theoretical results.

  5. What big size you have! Using effect sizes to determine the impact of public health nursing interventions.

    Science.gov (United States)

    Johnson, K E; McMorris, B J; Raynor, L A; Monsen, K A

    2013-01-01

    The Omaha System is a standardized interface terminology that is used extensively by public health nurses in community settings to document interventions and client outcomes. Researchers using Omaha System data to analyze the effectiveness of interventions have typically calculated p-values to determine whether significant client changes occurred between admission and discharge. However, p-values are highly dependent on sample size, making it difficult to distinguish statistically significant changes from clinically meaningful changes. Effect sizes can help identify practical differences but have not yet been applied to Omaha System data. We compared p-values and effect sizes (Cohen's d) for mean differences between admission and discharge for 13 client problems documented in the electronic health records of 1,016 young low-income parents. Client problems were documented anywhere from 6 (Health Care Supervision) to 906 (Caretaking/parenting) times. On a scale from 1 to 5, the mean change needed to yield a large effect size (Cohen's d ≥ 0.80) was approximately 0.60 (range = 0.50 - 1.03) regardless of p-value or sample size (i.e., the number of times a client problem was documented in the electronic health record). Researchers using the Omaha System should report effect sizes to help readers determine which differences are practical and meaningful. Such disclosures will allow for increased recognition of effective interventions.

  6. Effect of Particle Size on Thermal Conductivity of Nanofluid

    Science.gov (United States)

    Chopkar, M.; Sudarshan, S.; Das, P. K.; Manna, I.

    2008-07-01

    Nanofluids, containing nanometric metallic or oxide particles, exhibit extraordinarily high thermal conductivity. It is reported that the identity (composition), amount (volume percent), size, and shape of nanoparticles largely determine the extent of this enhancement. In the present study, we have experimentally investigated the impact of Al2Cu and Ag2Al nanoparticle size and volume fraction on the effective thermal conductivity of water and ethylene glycol based nanofluid prepared by a two-stage process comprising mechanical alloying of appropriate Al-Cu and Al-Ag elemental powder blend followed by dispersing these nanoparticles (1 to 2 vol pct) in water and ethylene glycol with different particle sizes. The thermal conductivity ratio of nanofluid, measured using an indigenously developed thermal comparator device, shows a significant increase of up to 100 pct with only 1.5 vol pct nanoparticles of 30- to 40-nm average diameter. Furthermore, an analytical model shows that the interfacial layer significantly influences the effective thermal conductivity ratio of nanofluid for the comparable amount of nanoparticles.

  7. Size effect in barium titanate powders synthesized by different hydrothermal methods

    International Nuclear Information System (INIS)

    Sun Weian

    2006-01-01

    The size effect in barium titanate (BaTiO 3 ) was investigated both experimentally and theoretically. Tetragonal BaTiO 3 powders with average sizes from 80 to 420 nm were directly prepared by different hydrothermal methods. The tetragonality of the hydrothermal BaTiO 3 decreased with decreasing particle size, which exhibited a dependence on the synthesis method. A phenomenological model for the size effect was proposed to interpret the experimental observations. The influence of the defects, mainly the lattice hydroxyl, on the size effect was investigated to understand the correlation between the size effect and synthesis condition. The permittivities of BaTiO 3 powder at different particle sizes were calculated, which predicted a maximum permittivity of over 16 000 around the room-temperature critical size of ∼70 nm. The prediction was in good accordance with the experimental data reported recently

  8. Effect of meal size and body size on specific dynamic action and gastric processing in decapod crustaceans.

    Science.gov (United States)

    McGaw, Iain J; Curtis, Daniel L

    2013-11-01

    Meal size and animal size are important factors affecting the characteristics of the specific dynamic action (SDA) response across a variety of taxa. The effects of these two variables on the SDA of decapod crustaceans are based on just a couple of articles, and are not wholly consistent with the responses reported for other aquatic ectotherms. Therefore, the effects of meal size and animal size on the characteristics of SDA response were investigated in a variety of decapod crustaceans from different families. A 6 fold increase in meal size (0.5%-3% body mass) resulted a pronounced increase in the duration of increased oxygen consumption, resulting in an increase in the SDA of Callinectes sapidus, Cancer gracilis, Hemigrapsus nudus, Homarus americanus, Pugettia producta and Procambarus clarkii. Unlike many other aquatic ectotherms a substantial increase between meal sizes was required, with meal size close to their upper feeding limit (3% body mass), before changes were evident. In many organisms increases in both duration and scope contribute to the overall SDA, here changes in scope as a function of meal size were weak, suggesting that a similar amount of energy is required to upregulate gastric processes, regardless of meal size. The SDA characteristics were less likely to be influenced by the size of the animal, and there was no difference in the SDA (kJ) as a function of size in H. americanus or Cancer irroratus when analysed as mass specific values. In several fish species characteristics of the SDA response are more closely related to the transit times of food, rather than the size of a meal. To determine if a similar trend occurred in crustaceans, the transit rates of different sized meals were followed through the digestive system using a fluoroscope. Although there was a trend towards larger meals taking longer to pass through the gut, this was only statistically significant for P. clarkii. There were some changes in transit times as a function of animal

  9. Finite size effects of a pion matrix element

    International Nuclear Information System (INIS)

    Guagnelli, M.; Jansen, K.; Palombi, F.; Petronzio, R.; Shindler, A.; Wetzorke, I.

    2004-01-01

    We investigate finite size effects of the pion matrix element of the non-singlet, twist-2 operator corresponding to the average momentum of non-singlet quark densities. Using the quenched approximation, they come out to be surprisingly large when compared to the finite size effects of the pion mass. As a consequence, simulations of corresponding nucleon matrix elements could be affected by finite size effects even stronger which could lead to serious systematic uncertainties in their evaluation

  10. Dispersant Effectiveness, In-Situ Droplet Size Distribution and ...

    Science.gov (United States)

    This report summarizes two projects covered under an Interagency Agreement between the Bureau of Safety and Environmental Enforcement (BSEE) and the U.S. Environmental Protection Agency (EPA) in collaboration with the Bedford Institute of Oceanography, Department of Fisheries and Oceans Canada (BIO DFO), New Jersey Institute of Technology (NJIT) and Dalhousie University. Both projects dovetail together in addressing the ability to differentiate physical from chemical dispersion effectiveness using dispersed oil simulations within a flume tank for improving forensic response monitoring tools. This report is split into separateTasks based upon the two projects funded by BSEE: 1) Dispersant Effectiveness, In-Situ Droplet Size Distribution and Numerical Modeling to Assess Subsurface Dispersant Injection as a Deepwater Blowout Oil Spill Response Option. 2) Evaluation of Oil Fluorescence Characteristics to Improve Forensic Response Tools. This report summarizes 2 collaborative projects funded through an Interagency Agreement with DOI BSEE and a Cooperative Agreement with DFO Canada. BSEE required that the projects be combined into one report as they are both covered under the one Interagency Agreement. Task B (Fluorescence of oils) is an SHC 3.62 FY16 product.

  11. Effect of particle size distribution on sintering of tungsten

    International Nuclear Information System (INIS)

    Patterson, B.R.; Griffin, J.A.

    1984-01-01

    To date, very little is known about the effect of the nature of the particle size distribution on sintering. It is reasonable that there should be an effect of size distribution, and theory and prior experimental work examining the effects of variations in bimodal and continuous distributions have shown marked effects on sintering. Most importantly, even with constant mean particle size, variations in distribution width, or standard deviation, have been shown to produce marked variations in microstructure and sintering rate. In the latter work, in which spherical copper powders were blended to produce lognormal distributions of constant geometric mean particle size by weight frequency, blends with larger values of geometric standard deviation, 1nσ, sintered more rapidly. The goals of the present study were to examine in more detail the effects of variations in the width of lognormal particle size distributions of tungsten powder and determine the effects of 1nσ on the microstructural evolution during sintering

  12. Family size and effective population size in a hatchery stock of coho salmon (Oncorhynchus kisutch)

    Science.gov (United States)

    Simon, R.C.; McIntyre, J.D.; Hemmingsen, A.R.

    1986-01-01

    Means and variances of family size measured in five year-classes of wire-tagged coho salmon (Oncorhynchus kisutch) were linearly related. Population effective size was calculated by using estimated means and variances of family size in a 25-yr data set. Although numbers of age 3 adults returning to the hatchery appeared to be large enough to avoid inbreeding problems (the 25-yr mean exceeded 4500), the numbers actually contributing to the hatchery production may be too low. Several strategies are proposed to correct the problem perceived. Argument is given to support the contention that the problem of effective size is fairly general and is not confined to the present study population.

  13. Size effects in nanoindentation: an experimental and analytical study

    NARCIS (Netherlands)

    Voyiadjis, G.Z.; Peters, Rick

    2009-01-01

    This work addresses the size effect encountered in nanoindentation experiments. It is generally referred to as the indentation size effect (ISE). Classical descriptions of the ISE show a decrease in hardness for increasing indentation depth. Recently new experiments have shown that after the initial

  14. Do Effect-Size Measures Measure up?: A Brief Assessment

    Science.gov (United States)

    Onwuegbuzie, Anthony J.; Levin, Joel R.; Leech, Nancy L.

    2003-01-01

    Because of criticisms leveled at statistical hypothesis testing, some researchers have argued that measures of effect size should replace the significance-testing practice. We contend that although effect-size measures have logical appeal, they are also associated with a number of limitations that may result in problematic interpretations of them…

  15. Generation time and effective population size in Polar Eskimos

    Science.gov (United States)

    Matsumura, Shuichi; Forster, Peter

    2008-01-01

    North Greenland Polar Eskimos are the only hunter–gatherer population, to our knowledge, who can offer precise genealogical records spanning several generations. This is the first report from Eskimos on two key parameters in population genetics, namely, generation time (T) and effective population size (Ne). The average mother–daughter and father–son intervals were 27 and 32 years, respectively, roughly similar to the previously published generation times obtained from recent agricultural societies across the world. To gain an insight for the generation time in our distant ancestors, we calculated maternal generation time for two wild chimpanzee populations. We also provide the first comparison among three distinct approaches (genealogy, variance and life table methods) for calculating Ne, which resulted in slightly differing values for the Eskimos. The ratio of the effective to the census population size is estimated as 0.6–0.7 for autosomal and X-chromosomal DNA, 0.7–0.9 for mitochondrial DNA and 0.5 for Y-chromosomal DNA. A simulation of alleles along the genealogy suggested that Y-chromosomal DNA may drift a little faster than mitochondrial DNA in this population, in contrast to agricultural Icelanders. Our values will be useful not only in prehistoric population inference but also in understanding the shaping of our genome today. PMID:18364314

  16. Hall measurements and grain-size effects in polycrystalline silicon

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Rose, A.; Maruska, H.P.; Eustace, D.J.; Feng, T.

    1980-01-01

    The effects of grain size on Hall measurements in polycrystalline silicon are analyzed and interpreted, with some modifications, using the model proposed by Bube. This modified model predicts that the measured effective Hall voltage is composed of components originating from the bulk and space-charge regions. For materials with large grain sizes, the carrier concentration is independent of the intergrain boundary barrier, whereas the mobility is dependent on it. However, for small grains, both the carrier density and mobility depend on the barrier. These predictions are consistent with experimental results of mm-size Wacker and μm-size neutron-transmutation-doped polycrystalline silicon

  17. The quality of the reported sample size calculations in randomized controlled trials indexed in PubMed.

    Science.gov (United States)

    Lee, Paul H; Tse, Andy C Y

    2017-05-01

    There are limited data on the quality of reporting of information essential for replication of the calculation as well as the accuracy of the sample size calculation. We examine the current quality of reporting of the sample size calculation in randomized controlled trials (RCTs) published in PubMed and to examine the variation in reporting across study design, study characteristics, and journal impact factor. We also reviewed the targeted sample size reported in trial registries. We reviewed and analyzed all RCTs published in December 2014 with journals indexed in PubMed. The 2014 Impact Factors for the journals were used as proxies for their quality. Of the 451 analyzed papers, 58.1% reported an a priori sample size calculation. Nearly all papers provided the level of significance (97.7%) and desired power (96.6%), and most of the papers reported the minimum clinically important effect size (73.3%). The median (inter-quartile range) of the percentage difference of the reported and calculated sample size calculation was 0.0% (IQR -4.6%;3.0%). The accuracy of the reported sample size was better for studies published in journals that endorsed the CONSORT statement and journals with an impact factor. A total of 98 papers had provided targeted sample size on trial registries and about two-third of these papers (n=62) reported sample size calculation, but only 25 (40.3%) had no discrepancy with the reported number in the trial registries. The reporting of the sample size calculation in RCTs published in PubMed-indexed journals and trial registries were poor. The CONSORT statement should be more widely endorsed. Copyright © 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  18. Electrokinetic Flow in Microchannels with Finite Reservoir Size Effects

    International Nuclear Information System (INIS)

    Yan, D; Yang, C; Nguyen, N-T; Huang, X

    2006-01-01

    In electrokinetically-driven microfluidic applications, reservoirs are indispensable and have finite sizes. During operation processes, as the liquid level difference in reservoirs keeps changing as time elapses, the flow characteristics in a microchannel exhibit a combination of the electroosmotic flow and the time-dependent induced backpressure-driven flow. In this work, an assessment of the finite reservoir size effect on electroosmotic flows is presented theoretically and experimentally. A model is developed to describe the timedependent electrokinetic flow with finite reservoir size effects. The theoretical analysis shows that under certain conditions the finite reservoir size effect is significant. The important parameters that describe the effect of finite reservoir size on the flow characteristics are discussed. A new concept denoted as 'effective pumping period' is introduced to characterize the reservoir size effect. The proposed model clearly identifies the mechanisms of the finitereservoir size effects and is further confirmed by using micro-PIV technique. The results of this study can be used for facilitating the design of microfluidic devices

  19. EFFECTS OF ULTRASOUND ON THE MORPHOLOGY, PARTICLE SIZE, CRYSTALLINITY, AND CRYSTALLITE SIZE OF CELLULOSE

    Directory of Open Access Journals (Sweden)

    SUMARI SUMARI

    2014-05-01

    Full Text Available The aim of this study is to optimize ultrasound treatment to produce fragment of cellulose that is low in particles size, crystallite size, and crystallinity. Slurry of 1 % (w/v the cellulose was sonicated at different time periods and temperatures. An ultrasonic reactor was operated at 300 Watts and 28 kHz to cut down the polymer into smaller particles. We proved that ultrasound damages and fragments the cellulose particles into shorter fibers. The fiber lengths were reduced from in the range of 80-120 µm to 30-50 µm due to an hour ultrasonication and became 20-30 µm after 5 hours. It was also found some signs of erosion on the surface and stringy. The acoustic cavitation also generated a decrease in particle size, crystallinity, and crystallite size of the cellulose along with increasing sonication time but it did not change d-spacing. However, the highest reduction of particle size, crystallite size, and crystallinity of the cellulose occurred within the first hour of ultrasonication, after which the efficiency was decreased. The particle diameter, crystallite size, and crystallinity were decreased from 19.88 µm to 15.96 µm, 5.81 Å to 2.98 Å, and 77.7% to 73.9% respectively due to an hour ultrasound treatment at 40 °C. The treatment that was conducted at 40 °C or 60 °C did not give a different effect significantly. Cellulose with a smaller particle and crystallite size as well as a more amorphous shape is preferred for further study.

  20. Size effects in the mechanical behavior of cellular materials

    NARCIS (Netherlands)

    Tekoglu, C; Onck, PR

    Effective mechanical properties of cellular materials depend strongly on the specimen size to the cell size ratio. Experimental studies performed on aluminium foams show that under uniaxial compression, the stiffness of these materials falls below the corresponding bulk value, when the ratio of the

  1. Effects of sample size on the second magnetization peak in ...

    Indian Academy of Sciences (India)

    8+ crystals are observed at low temperatures, above the temperature where the SMP totally disappears. In particular, the onset of the SMP shifts to lower fields as the sample size decreases - a result that could be interpreted as a size effect in ...

  2. The effects of meal size, body size and temperature on gastric evacuation in pikeperch

    DEFF Research Database (Denmark)

    Koed, Anders

    2001-01-01

    Prey size had no effect on the gastric evacuation rate of pikeperch Stizostedion lucioperca. The gastric evacuation was adequately described applying an exponent of 0.5 in the power model. Applying length instead of weight of pikeperch in the gastric evacuation model resulted in a change of estim...

  3. Zn incorporation in CuInSe2: Particle size and strain effects on ...

    Indian Academy of Sciences (India)

    Administrator

    Zn incorporation in CuInSe2: Particle size and strain effects on microstructural ... size as well as tensile strain. The calculated ... X-ray diffraction analysis of CuInSe2 samples reported in figure 2 ... To estimate qualitative information regarding ...

  4. Effects of anion size and concentration on electrolyte invasion into molecular-sized nanopores

    International Nuclear Information System (INIS)

    Liu Ling; Chen Xi; Kim, Taewan; Han Aijie; Qiao Yu

    2010-01-01

    When an electrolyte solution is pressurized into a molecular-sized nanopore, oppositely charged ions are strongly inclined to aggregate, which effectively reduces the ion solubility to zero. Inside the restrictive confinement, a unique quasi-periodic structure is formed where the paired ion couples are periodically separated by a number of water molecules. As the anion size or ion concentration varies, the geometrical characteristics of the confined ion structure would change considerably, leading to a significant variation in the transport pressure. Both experimental and simulation results indicate that, contradictory to the prediction of conventional theory, infiltration pressure decreases as the anions become larger.

  5. EFFECT OF FARM SIZE AND FREQUENCY OF CUTTING ON ...

    African Journals Online (AJOL)

    EFFECT OF FARM SIZE AND FREQUENCY OF CUTTING ON OUTPUT OF ... the use of Ordinary Least Square (OLS) estimation technique was used in analyzing ... frequency of cutting that would produce maximum output of the vegetable as ...

  6. Size effect in tension perpendicular to the grain

    DEFF Research Database (Denmark)

    Pedersen, Martin Bo Uhre; Clorius, Christian Odin; Damkilde, Lars

    1999-01-01

    The strength in tension perpendicular to the grain is known to decrease with an increase in the stressed volume. Usually this size effect is explained on a stochastic basis, that is an explanation relying on an increased probability of encountering a strength reducing flaw when the volume...... of the material under stress is increased. This paper presents a small experimental investigation on specimens with well defined structural orientation of the material. The experiments exhibit a larger size effect than expected and furthermore the data and the nature of the failures encountered suggest...... that the size effect can be explained on a deterministic basis. Arguments for such a simple deterministic explanation of size effect is found in finite element modelling using the orthotropic stiffness characteristics in the transverse plane of wood....

  7. Distinguishing crystallite size effects from those of structural disorder ...

    Indian Academy of Sciences (India)

    Administrator

    Both crystallite size effects and structural disorder contribute to the broadening of lines in .... ple contributions to the peak profiles. ... the fit is then corrected by accounting for sample ... Authors thank the Department of Science and Tech-.

  8. Finite size effects in the intermittency analysis of the fragment-size correlations

    International Nuclear Information System (INIS)

    Bozek, P.; Ploszajczak, M.; Tucholski, A.

    1991-01-01

    An influence of the finite size effect on the fragment-size correlations in the nuclear multifragmentation is studied using the method of scaled factorial moments for a 1 - dim percolation model and for a statistical model of the fragmentation process, which for a certain value of a tuning parameter yields the power-law behaviour of the fragment-size distribution. It is shown that the statistical models of this type contain only repulsive correlations due to the conservation laws. The comparison of the results with those obtained in the non-critical 1 - dim percolation and in the 3 - dim percolation at around the critical point is presented. Correlations in the 1 - dim percolation model are analysed analytically and the mechanism of the attractive correlations in 1 - dim and 3 - dim is identified. (author) 30 refs., 7 figs

  9. Economic Effects of Increased Control Zone Sizes in Conflict Resolution

    Science.gov (United States)

    Datta, Koushik

    1998-01-01

    A methodology for estimating the economic effects of different control zone sizes used in conflict resolutions between aircraft is presented in this paper. The methodology is based on estimating the difference in flight times of aircraft with and without the control zone, and converting the difference into a direct operating cost. Using this methodology the effects of increased lateral and vertical control zone sizes are evaluated.

  10. Effect of particle size on the glass transition.

    Science.gov (United States)

    Larsen, Ryan J; Zukoski, Charles F

    2011-05-01

    The glass transition temperature of a broad class of molecules is shown to depend on molecular size. This dependency results from the size dependence of the pair potential. A generalized equation of state is used to estimate how the volume fraction at the glass transition depends on the size of the molecule, for rigid molecule glass-formers. The model shows that at a given pressure and temperature there is a size-induced glass transition: For molecules larger than a critical size, the volume fraction required to support the effective pressure due to particle attractions is above that which characterizes the glassy state. This observation establishes the boundary between nanoparticles, which exist in liquid form only as dispersions in low molecular weight solvents and large molecules which form liquids that have viscosities below those characterized by the glassy state.

  11. Blouse sizing using self-reported body dimensions

    NARCIS (Netherlands)

    Daanen, Hein A M; Byvoet, Michel B.

    2011-01-01

    Purpose: The challenge for companies selling clothing over the internet is to combine a minimal requested effort of the visitor in entering (body) information with low-percentage no-fit returns. The purpose of this paper is to present a method that converts self-reported information to individual

  12. Atomistic calculation of size effects on elastic coefficients in nanometre-sized tungsten layers and wires

    International Nuclear Information System (INIS)

    Villain, P.; Beauchamp, P.; Badawi, K.F.; Goudeau, P.; Renault, P.-O.

    2004-01-01

    Equilibrium state and elastic coefficients of nanometre-sized single crystal tungsten layers and wires are investigated by atomistic simulations. The variations of the equilibrium distances as a function of the layer thickness or wire cross-section are mainly due to elastic effects of surface tension forces. A strong decrease of the Young's modulus is observed when the transverse dimensions are reduced below 2-3 nm

  13. Long-Term Effects of School Size on Students' Outcomes

    DEFF Research Database (Denmark)

    Humlum, Maria Knoth; Smith, Nina

    We estimate the effect of school size on students' long-term outcomes such as high school completion, being out of the labor market, and earnings at the age of 30. We use rich register data on the entire population of Danish children attending grade 9 in the period 1986-2004. This allows us...... school size and alternative measures of long-term success in the educational system and the labor market. The positive impact of school size seems mainly to be driven by boys, students from families with a low educational level and students attending schools in urban areas....

  14. Object size effects on initial lifting forces under microgravity conditions

    NARCIS (Netherlands)

    Kingma, I.; Savelsbergh, G.J.P.; Toussaint, H.M.

    1999-01-01

    Individuals usually report for two objects of equal mass but different volume that the larger object feels lighter. This so-called size-weight illusion has been investigated for more than a century. The illusion is accompanied by increased forces, used to lift the larger object, resulting in a

  15. Selection dramatically reduces effective population size in HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Mittler John E

    2008-05-01

    Full Text Available Abstract Background In HIV-1 evolution, a 100–100,000 fold discrepancy between census size and effective population size (Ne has been noted. Although it is well known that selection can reduce Ne, high in vivo mutation and recombination rates complicate attempts to quantify the effects of selection on HIV-1 effective size. Results We use the inbreeding coefficient and the variance in allele frequency at a linked neutral locus to estimate the reduction in Ne due to selection in the presence of mutation and recombination. With biologically realistic mutation rates, the reduction in Ne due to selection is determined by the strength of selection, i.e., the stronger the selection, the greater the reduction. However, the dependence of Ne on selection can break down if recombination rates are very high (e.g., r ≥ 0.1. With biologically likely recombination rates, our model suggests that recurrent selective sweeps similar to those observed in vivo can reduce within-host HIV-1 effective population sizes by a factor of 300 or more. Conclusion Although other factors, such as unequal viral reproduction rates and limited migration between tissue compartments contribute to reductions in Ne, our model suggests that recurrent selection plays a significant role in reducing HIV-1 effective population sizes in vivo.

  16. Effect of small mapping population sizes on reliability of quantitative ...

    African Journals Online (AJOL)

    A limitation of quantitative trait loci (QTL) mapping is that accuracy of determining QTL position and effects are largely determined by population size. Despite the importance of this concept, known as the "Beavis effect there has generally been a lack of understanding by molecular geneticists and breeders. One possible ...

  17. Nanometer size field effect transistors for terahertz detectors

    International Nuclear Information System (INIS)

    Knap, W; Rumyantsev, S; Coquillat, D; Dyakonova, N; Teppe, F; Vitiello, M S; Tredicucci, A; Blin, S; Shur, M; Nagatsuma, T

    2013-01-01

    Nanometer size field effect transistors can operate as efficient resonant or broadband terahertz detectors, mixers, phase shifters and frequency multipliers at frequencies far beyond their fundamental cut-off frequency. This work is an overview of some recent results concerning the application of nanometer scale field effect transistors for the detection of terahertz radiation. (paper)

  18. An Introduction to Confidence Intervals for Both Statistical Estimates and Effect Sizes.

    Science.gov (United States)

    Capraro, Mary Margaret

    This paper summarizes methods of estimating confidence intervals, including classical intervals and intervals for effect sizes. The recent American Psychological Association (APA) Task Force on Statistical Inference report suggested that confidence intervals should always be reported, and the fifth edition of the APA "Publication Manual"…

  19. Large size self-assembled quantum rings: quantum size effect and modulation on the surface diffusion.

    Science.gov (United States)

    Tong, Cunzhu; Yoon, Soon Fatt; Wang, Lijun

    2012-09-24

    We demonstrate experimentally the submicron size self-assembled (SA) GaAs quantum rings (QRs) by quantum size effect (QSE). An ultrathin In0.1 Ga0.9As layer with different thickness is deposited on the GaAs to modulate the surface nucleus diffusion barrier, and then the SA QRs are grown. It is found that the density of QRs is affected significantly by the thickness of inserted In0.1 Ga0.9As, and the diffusion barrier modulation reflects mainly on the first five monolayer . The physical mechanism behind is discussed. The further analysis shows that about 160 meV decrease in diffusion barrier can be achieved, which allows the SA QRs with density of as low as one QR per 6 μm2. Finally, the QRs with diameters of 438 nm and outer diameters of 736 nm are fabricated using QSE.

  20. Effect size and statistical power in the rodent fear conditioning literature - A systematic review.

    Science.gov (United States)

    Carneiro, Clarissa F D; Moulin, Thiago C; Macleod, Malcolm R; Amaral, Olavo B

    2018-01-01

    Proposals to increase research reproducibility frequently call for focusing on effect sizes instead of p values, as well as for increasing the statistical power of experiments. However, it is unclear to what extent these two concepts are indeed taken into account in basic biomedical science. To study this in a real-case scenario, we performed a systematic review of effect sizes and statistical power in studies on learning of rodent fear conditioning, a widely used behavioral task to evaluate memory. Our search criteria yielded 410 experiments comparing control and treated groups in 122 articles. Interventions had a mean effect size of 29.5%, and amnesia caused by memory-impairing interventions was nearly always partial. Mean statistical power to detect the average effect size observed in well-powered experiments with significant differences (37.2%) was 65%, and was lower among studies with non-significant results. Only one article reported a sample size calculation, and our estimated sample size to achieve 80% power considering typical effect sizes and variances (15 animals per group) was reached in only 12.2% of experiments. Actual effect sizes correlated with effect size inferences made by readers on the basis of textual descriptions of results only when findings were non-significant, and neither effect size nor power correlated with study quality indicators, number of citations or impact factor of the publishing journal. In summary, effect sizes and statistical power have a wide distribution in the rodent fear conditioning literature, but do not seem to have a large influence on how results are described or cited. Failure to take these concepts into consideration might limit attempts to improve reproducibility in this field of science.

  1. Effect size and statistical power in the rodent fear conditioning literature – A systematic review

    Science.gov (United States)

    Macleod, Malcolm R.

    2018-01-01

    Proposals to increase research reproducibility frequently call for focusing on effect sizes instead of p values, as well as for increasing the statistical power of experiments. However, it is unclear to what extent these two concepts are indeed taken into account in basic biomedical science. To study this in a real-case scenario, we performed a systematic review of effect sizes and statistical power in studies on learning of rodent fear conditioning, a widely used behavioral task to evaluate memory. Our search criteria yielded 410 experiments comparing control and treated groups in 122 articles. Interventions had a mean effect size of 29.5%, and amnesia caused by memory-impairing interventions was nearly always partial. Mean statistical power to detect the average effect size observed in well-powered experiments with significant differences (37.2%) was 65%, and was lower among studies with non-significant results. Only one article reported a sample size calculation, and our estimated sample size to achieve 80% power considering typical effect sizes and variances (15 animals per group) was reached in only 12.2% of experiments. Actual effect sizes correlated with effect size inferences made by readers on the basis of textual descriptions of results only when findings were non-significant, and neither effect size nor power correlated with study quality indicators, number of citations or impact factor of the publishing journal. In summary, effect sizes and statistical power have a wide distribution in the rodent fear conditioning literature, but do not seem to have a large influence on how results are described or cited. Failure to take these concepts into consideration might limit attempts to improve reproducibility in this field of science. PMID:29698451

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

    Science.gov (United States)

    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…

  3. The reported availability of general practitioners and the influence of practice list size.

    OpenAIRE

    Campbell, J L

    1996-01-01

    BACKGROUND: Combined practice list sizes have increased, but larger practice size may be associated with disadvantage to patients. AIM: The aim of the study was to investigate the availability of general practitioners as reported by their patients and the relationship between reported availability and practice list size. METHOD: A one-week questionnaire survey of 8315 patients attending participating practices in West Lothian, Scotland, was conducted. Patients were asked about the arrangement...

  4. Specific cesium activity in freshwater fish and the size effect

    International Nuclear Information System (INIS)

    Kulikov, A.O.; Ryabov, I.N.; USSR Academy of Sciences, Moscow

    1992-01-01

    The specific Cs-137 activity of muscle tissues of silver carp (Hypophthalmichthys molitrix) from the cooling pond of the Chernobyl nuclear power plant caught in 1987 and 1988 increased almost linearly with fish weight ('size effect') in contrast to liver tissue, whose specific activity remained independent of weight. A kinetic model for uptake and excretion was developed to describe the size effect in muscle tissue by introducing a weight-dependent Cs biological half-time to fish. Similar size effects of specific Cs-137 activity were also found for other species of fish from cooling pond, but were primarily attributed to changes in feeding habits with increasing weight of fish rather than to metabolic changes in feeding habits with both of muscle and liver tissue increased with fish weight for those species in contrast to silver carp. (author). 12 refs.; 12 figs.; 1 tab

  5. Study of Cluster-size Effect on Damage Formation

    International Nuclear Information System (INIS)

    Aoki, Takaaki; Seki, Toshio; Nakai, Atsuko; Matsuo, Jiro; Takaoka, Gikan

    2003-01-01

    Computer simulation and experiments were performed in order to understand the effect of cluster size on damage formation. Results of molecular dynamics simulations of cluster impact on solid targets derived the model function, which explains the relationship among cluster size, incident energy and number of displacements. On the other hand, time of flight mass measurement system was installed a cluster irradiation system, so that cluster ion beam which cluster size distribution is well known can be irradiated on the target. The damage properties under various cluster irradiation conditions were examined using RBS. The results from computer simulations and experiments showed good agreements with each other, which suggests that irradiation damage by cluster ion beam can be controlled by selecting cluster size distribution and incident energy

  6. Does neighborhood size really cause the word length effect?

    Science.gov (United States)

    Guitard, Dominic; Saint-Aubin, Jean; Tehan, Gerald; Tolan, Anne

    2018-02-01

    In short-term serial recall, it is well-known that short words are remembered better than long words. This word length effect has been the cornerstone of the working memory model and a benchmark effect that all models of immediate memory should account for. Currently, there is no consensus as to what determines the word length effect. Jalbert and colleagues (Jalbert, Neath, Bireta, & Surprenant, 2011a; Jalbert, Neath, & Surprenant, 2011b) suggested that neighborhood size is one causal factor. In six experiments we systematically examined their suggestion. In Experiment 1, with an immediate serial recall task, multiple word lengths, and a large pool of words controlled for neighborhood size, the typical word length effect was present. In Experiments 2 and 3, with an order reconstruction task and words with either many or few neighbors, we observed the typical word length effect. In Experiment 4 we tested the hypothesis that the previous abolition of the word length effect when neighborhood size was controlled was due to a confounded factor: frequency of orthographic structure. As predicted, we reversed the word length effect when using short words with less frequent orthographic structures than the long words, as was done in both of Jalbert et al.'s studies. In Experiments 5 and 6, we again observed the typical word length effect, even if we controlled for neighborhood size and frequency of orthographic structure. Overall, the results were not consistent with the predictions of Jalbert et al. and clearly showed a large and reliable word length effect after controlling for neighborhood size.

  7. R2 effect-size measures for mediation analysis

    Science.gov (United States)

    Fairchild, Amanda J.; MacKinnon, David P.; Taborga, Marcia P.; Taylor, Aaron B.

    2010-01-01

    R2 effect-size measures are presented to assess variance accounted for in mediation models. The measures offer a means to evaluate both component paths and the overall mediated effect in mediation models. Statistical simulation results indicate acceptable bias across varying parameter and sample-size combinations. The measures are applied to a real-world example using data from a team-based health promotion program to improve the nutrition and exercise habits of firefighters. SAS and SPSS computer code are also provided for researchers to compute the measures in their own data. PMID:19363189

  8. R2 effect-size measures for mediation analysis.

    Science.gov (United States)

    Fairchild, Amanda J; Mackinnon, David P; Taborga, Marcia P; Taylor, Aaron B

    2009-05-01

    R(2) effect-size measures are presented to assess variance accounted for in mediation models. The measures offer a means to evaluate both component paths and the overall mediated effect in mediation models. Statistical simulation results indicate acceptable bias across varying parameter and sample-size combinations. The measures are applied to a real-world example using data from a team-based health promotion program to improve the nutrition and exercise habits of firefighters. SAS and SPSS computer code are also provided for researchers to compute the measures in their own data.

  9. The effect of scaffold pore size in cartilage tissue engineering.

    Science.gov (United States)

    Nava, Michele M; Draghi, Lorenza; Giordano, Carmen; Pietrabissa, Riccardo

    2016-07-26

    The effect of scaffold pore size and interconnectivity is undoubtedly a crucial factor for most tissue engineering applications. The aim of this study was to examine the effect of pore size and porosity on cartilage construct development in different scaffolds seeded with articular chondrocytes. We fabricated poly-L-lactide-co-trimethylene carbonate scaffolds with different pore sizes, using a solvent-casting/particulate-leaching technique. We seeded primary bovine articular chondrocytes on these scaffolds, cultured the constructs for 2 weeks and examined cell proliferation, viability and cell-specific production of cartilaginous extracellular matrix proteins, including GAG and collagen. Cell density significantly increased up to 50% with scaffold pore size and porosity, likely facilitated by cell spreading on the internal surface of bigger pores, and by increased mass transport of gases and nutrients to cells, and catabolite removal from cells, allowed by lower diffusion barriers in scaffolds with a higher porosity. However, both the cell metabolic activity and the synthesis of cartilaginous matrix proteins significantly decreased by up to 40% with pore size. We propose that the association of smaller pore diameters, causing 3-dimensional cell aggregation, to a lower oxygenation caused by a lower porosity, could have been the condition that increased the cell-specific synthesis of cartilaginous matrix proteins in the scaffold with the smallest pores and the lowest porosity among those tested. In the initial steps of in vitro cartilage engineering, the combination of small scaffold pores and low porosity is an effective strategy with regard to the promotion of chondrogenesis.

  10. Atomic size effect on critical cooling rate and glass formation

    International Nuclear Information System (INIS)

    Jalali, Payman; Li Mo

    2005-01-01

    Atomic size effect on critical cooling rate and glass formability in a model binary system is investigated using molecular dynamics simulation. To isolate atomic size effect from the rest of the factors that critically influence the glass formation, a hard sphere model is employed in conjunction with a newly developed densification method. The glass formability is defined as a set of optimal conditions that result in the slowest cooling rate of the glass-forming liquid. Critical cooling rates are identified from extensive molecular dynamics simulations. A kinetic glass-forming diagram is mapped out that marks the boundary between the glass-forming regions and competing crystalline phases in terms of the parameters of the atomic size ratio and alloy concentration. It is found that the potency of the atomic size difference on glass formation is influenced greatly by the competing metastable and equilibrium crystalline phases in the system, and the kinetic processes leading to the formation of these phases. The mechanisms of the atomic size effect on topological instability of crystal packing and glass formation are discussed

  11. Core size effects on safety performances of LMRs

    Energy Technology Data Exchange (ETDEWEB)

    Na, Byung Chan; Hahn, Do Hee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    An oxide fuel small size core (1200 MWt) was analyzed in comparison with a large size core (3600 MWt) in order to evaluate the size effects on transient safety performances of liquid-metal reactors (LMRs). In the first part of the study, main static safety parameters (i.e., Doppler coefficient, sodium void effect, etc.) of the two cores were characterized, and the second part of the study was focused on the dynamic behavior of the cores in two representative transient events: the unprotected loss-of-flow (ULOF) and the unprotected transient overpower (UTOP). Margins to fuel melting and sodium boiling have been evaluated for these representative transients. Results show that the small core has a generally better or equivalent level of safety performances during these events. 6 refs., 4 figs., 2 tabs. (Author)

  12. Core size effects on safety performances of LMRs

    Energy Technology Data Exchange (ETDEWEB)

    Na, Byung Chan; Hahn, Do Hee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    An oxide fuel small size core (1200 MWt) was analyzed in comparison with a large size core (3600 MWt) in order to evaluate the size effects on transient safety performances of liquid-metal reactors (LMRs). In the first part of the study, main static safety parameters (i.e., Doppler coefficient, sodium void effect, etc.) of the two cores were characterized, and the second part of the study was focused on the dynamic behavior of the cores in two representative transient events: the unprotected loss-of-flow (ULOF) and the unprotected transient overpower (UTOP). Margins to fuel melting and sodium boiling have been evaluated for these representative transients. Results show that the small core has a generally better or equivalent level of safety performances during these events. 6 refs., 4 figs., 2 tabs. (Author)

  13. Effect of microfluidization on casein micelle size of bovine milk

    Science.gov (United States)

    Sinaga, H.; Deeth, H.; Bhandari, B.

    2018-02-01

    The properties of milk are likely to be dependent on the casein micelle size, and various processing technologies produce particular change in the average size of casein micelles. The main objective of this study was to manipulate casein micelle size by subjecting milk to microfluidizer. The experiment was performed as a complete block randomised design with three replications. The sample was passed through the microfluidizer at the set pressure of 83, 97, 112 and 126 MPa for one, two, three, four, five and six cycles, except for the 112 MPa. The results showed that microfluidized milk has smaller size by 3% with pressure up to 126 MPa. However, at each pressure, no further reduction was observed after increasing the passed up to 6 cycles. Although the average casein micelle size was similar, elevating pressure resulted in narrower size distribution. In contrast, increasing the number of cycles had little effect on casein micelle distribution. The finding from this study can be applied for future work to characterize the fundamental and functional properties of the treated milk.

  14. A STUDY OF TRANSVERSE AND LONGITUDINAL SIZE EFFECTS IN HIGH-STRENGTH POLYETHYLENE FIBERS

    NARCIS (Netherlands)

    PENNING, JP; DEVRIES, AA; PENNINGS, AJ; HOOGSTRATEN, HW

    The results of an experimental study of the effects of fibre diameter and testing length on the strength of polyethylene fibres prepared by the gel-spinning-hot-drawing process are reported. These size effects have been studied in fibres covering a range of mechanical properties in order to

  15. The Effect of Plot Size on Some Pratylenchus Penetrans ...

    African Journals Online (AJOL)

    Pratylenchus penetrans counts obtained from a rose field, sampled sequentially by decreasing the plot sizes were computed to obtain the respective sample means, variance and k-value of the negative binomial distribution. Plots 21 m x 80 m, 3.6 m x 3.6 m and 0.6 m x 0.6 m were sampled for the nematode. It is reported ...

  16. Statistical Significance and Effect Size: Two Sides of a Coin.

    Science.gov (United States)

    Fan, Xitao

    This paper suggests that statistical significance testing and effect size are two sides of the same coin; they complement each other, but do not substitute for one another. Good research practice requires that both should be taken into consideration to make sound quantitative decisions. A Monte Carlo simulation experiment was conducted, and a…

  17. Adaptive evolution and effective population size in wild house mice

    Czech Academy of Sciences Publication Activity Database

    Phifer-Rixey, M.; Bonhomme, F.; Boursot, P.; Churchill, G. A.; Piálek, Jaroslav; Tucker, P.; Nachman, M.

    2012-01-01

    Roč. 29, č. 10 (2012), s. 2949-2955 ISSN 0737-4038 R&D Projects: GA ČR GA206/08/0640 Institutional support: RVO:68081766 Keywords : substitution * adaptation * evolution * effective population size * house mouse Subject RIV: EG - Zoology Impact factor: 10.353, year: 2012

  18. Effect of limestone particle size on bone quality characteristics of ...

    African Journals Online (AJOL)

    A study was conducted to determine the effect of different limestone particle sizes in layer diets on bone quality characteristics at end-of-lay hens. Calcitic limestone (360 g Ca/kg DM) that is extensively used in commercial poultry diets was obtained from a specific South African source. Limestone particles were graded as ...

  19. Effects of Particle Size Distribution on Bioremediation of Crude Oil ...

    African Journals Online (AJOL)

    Bioremediation has been proven to be the most effective method of cleaning up oil contaminated soils through the application of nutrients and microorganism. ... The parameters examined were: moisture content, particle size distribution, total hydrocarbon content, soil pH, available nitrogen, available phosphorus, total ...

  20. Short communication Effective population size and inbreeding rate ...

    African Journals Online (AJOL)

    201010100

    2013-05-30

    May 30, 2013 ... Understanding and estimating effective population size for practical application in marine species management. Conservation Biology 25 (3), 438-449. Mapiye, C., Chimonyo, M., Muchenje, V., Dzama, K., Marufu, M.C. & Raats, J.G., 2007. Potential for value-addition of Nguni cattle products in the communal ...

  1. The effect of surface albedo and grain size distribution on ...

    African Journals Online (AJOL)

    Sand dams are very useful in arid and semi arid lands (ASALs) as facilities for water storage and conservation. Soils in ASALs are mainly sandy and major water loss is by evaporation and infiltration. This study investigated the effect of sand media characteristics, specifically surface albedo, grain size and stratification on ...

  2. Application of size effect to compressive strength of concrete members

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    (LSM) to obtain parameters for the modified size effect law (MSEL) by Kim and co workers. The results of the ... in tensile failure, because the formation of microcracks in compressive failure is distributed in a wider region ...... Benjamin J R, Cornell C A 1970 Probability, statistics, and decision for civil engineers (New York:.

  3. Effect of directional selection for body size on fluctuating asymmetry ...

    Indian Academy of Sciences (India)

    In this study, we investigated whether stress caused by artificial bidirectional selection for body size has any effect on the levels of FA of different morphological traits in Drosophila ananassae. The realised heritability (h2) was higher in low-line females and high-line males, which suggests an asymmetrical response to ...

  4. Effect of limestone particle size on egg production and eggshell ...

    African Journals Online (AJOL)

    Different limestone particle sizes had no effect on any of the tested egg production and eggshell quality parameters. These results suggested that larger particles limestone are not necessarily essential to provide sufficient Ca2+ to laying hens for egg production and eggshell quality at end-of-lay, provided that the dietary Ca ...

  5. Sampling strategies for estimating brook trout effective population size

    Science.gov (United States)

    Andrew R. Whiteley; Jason A. Coombs; Mark Hudy; Zachary Robinson; Keith H. Nislow; Benjamin H. Letcher

    2012-01-01

    The influence of sampling strategy on estimates of effective population size (Ne) from single-sample genetic methods has not been rigorously examined, though these methods are increasingly used. For headwater salmonids, spatially close kin association among age-0 individuals suggests that sampling strategy (number of individuals and location from...

  6. An Introductory Summary of Various Effect Size Choices.

    Science.gov (United States)

    Cromwell, Susan

    This paper provides a tutorial summary of some of the many effect size choices so that members of the Southwest Educational Research Association would be better able to follow the recommendations of the American Psychological Association (APA) publication manual, the APA Task Force on Statistical Inference, and the publication requirements of some…

  7. Short communication: Effective population size and inbreeding rate ...

    African Journals Online (AJOL)

    Short communication: Effective population size and inbreeding rate of indigenous Nguni cattle under in situ conservation in the low-input communal production ... as not at risk of extinction, while the individual enterprises were classified as being endangered-maintained without the exchange of germ plasm among them.

  8. Finite-size effects for anisotropic bootstrap percolation : Logarithmic corrections

    NARCIS (Netherlands)

    van Enter, Aernout C. D.; Hulshof, Tim

    In this note we analyse an anisotropic, two-dimensional bootstrap percolation model introduced by Gravner and Griffeath. We present upper and lower bounds on the finite-size effects. We discuss the similarities with the semi-oriented model introduced by Duarte.

  9. Finite-size effects for anisotropic bootstrap percolation: logerithmic corrections

    NARCIS (Netherlands)

    Enter, van A.C.D.; Hulshof, T.

    2007-01-01

    In this note we analyse an anisotropic, two-dimensional bootstrap percolation model introduced by Gravner and Griffeath. We present upper and lower bounds on the finite-size effects. We discuss the similarities with the semi-oriented model introduced by Duarte.

  10. Particles size distribution effect on 3D packing of nanoparticles in to a bounded region

    International Nuclear Information System (INIS)

    Farzalipour Tabriz, M.; Salehpoor, P.; Esmaielzadeh Kandjani, A.; Vaezi, M. R.; Sadrnezhaad, S. K.

    2007-01-01

    In this paper, the effects of two different Particle Size Distributions on packing behavior of ideal rigid spherical nanoparticles using a novel packing model based on parallel algorithms have been reported. A mersenne twister algorithm was used to generate pseudo random numbers for the particles initial coordinates. Also, for this purpose a nano sized tetragonal confined container with a square floor (300 * 300 nm) were used in this work. The Andreasen and the Lognormal Particle Size Distributions were chosen to investigate the packing behavior in a 3D bounded region. The effects of particle numbers on packing behavior of these two Particle Size Distributions have been investigated. Also the reproducibility and the distribution of packing factor of these Particle Size Distributions were compared

  11. Synthesis of nanometer-size inorganic materials for the examination of particle size effects on heterogeneous catalysis

    Science.gov (United States)

    Emerson, Sean Christian

    control of gold grain size was gained at the loss of CO activity, which was attributed to the formation of non-removable sodium titanate species. The increased mixing associated with cavitation contributed to the activity loss by partially burying the gold and incorporating more of the sodium titanate species into the catalysts. This work produced the first evidence of hydrodynamic cavitation influencing the gold crystallite size on titania supported gold catalysts and is the only study reporting the control of grain size by simple mechanical adjustment of the experimental parameters. Despite the low activity observed due to sodium titanate, the methodology of adjusting the chemistry of a precipitating system could be used to eliminate such species. The approach of modifying the chemical precipitation kinetics relative to the dynamics of cavitation offers a general scheme for future research on cavitational processing effects.

  12. Radiation inactivation analysis of enzymes. Effect of free radical scavengers on apparent target sizes

    International Nuclear Information System (INIS)

    Eichler, D.C.; Solomonson, L.P.; Barber, M.J.; McCreery, M.J.; Ness, G.C.

    1987-01-01

    In most cases the apparent target size obtained by radiation inactivation analysis corresponds to the subunit size or to the size of a multimeric complex. In this report, we examined whether the larger than expected target sizes of some enzymes could be due to secondary effects of free radicals. To test this proposal we carried out radiation inactivation analysis on Escherichia coli DNA polymerase I, Torula yeast glucose-6-phosphate dehydrogenase, Chlorella vulgaris nitrate reductase, and chicken liver sulfite oxidase in the presence and absence of free radical scavengers (benzoic acid and mannitol). In the presence of free radical scavengers, inactivation curves are shifted toward higher radiation doses. Plots of scavenger concentration versus enzyme activity showed that the protective effect of benzoic acid reached a maximum at 25 mM then declined. Mannitol alone had little effect, but appeared to broaden the maximum protective range of benzoic acid relative to concentration. The apparent target size of the polymerase activity of DNA polymerase I in the presence of free radical scavengers was about 40% of that observed in the absence of these agents. This is considerably less than the minimum polypeptide size and may reflect the actual size of the polymerase functional domain. Similar effects, but of lesser magnitude, were observed for glucose-6-phosphate dehydrogenase, nitrate reductase, and sulfite oxidase. These results suggest that secondary damage due to free radicals generated in the local environment as a result of ionizing radiation can influence the apparent target size obtained by this method

  13. Effect of coal stress on grain size of the gotten

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, W; Tront, A

    1988-09-01

    Presents investigation results on the effect of seam stress and strain state on winning as measured by the grain size of the gotten. The investigations were carried out at the Institute of Mining Mechanization of the Silesian Politechnical where the relations between parameters of seams and cutters and their effect on coal grain size and energy consumption have been studied for several years. The effect was examined on coal samples taken from 4 mines in the Upper Silesian coal basin using a model of the system: seam - cutter. Cubic samples (400x400x400 mm) were tested on the CMG KOMAG test stand equipped with the POS-1 cutting apparatus. Two types of coal were distinguished: that particularly sensitive to increased pressure on seam and that only negligibly susceptible. Corresponding graphs of coal grain size versus vertical pressure are shown. A function has been developed that characterizes this sensitivity depending on a material parameter that can be determined by workability tests. The relationship between coal strength and grain size yield greater than 10 mm in the gotten depending on dynamic crushability of coal is shown in graphs. 6 refs.

  14. The Effect of Size and Ecology on Extinction Susceptibility

    Science.gov (United States)

    Huynh, C.; Yuan, A.; Heim, N.; Payne, J.

    2015-12-01

    Although life on Earth first emerged as prokaryotic organisms, it eventually evolved into billions of different species. However, extinctions on Earth, especially the five mass extinctions, have decimated species. So what leads to a species survival or demise during a mass extinction? Are certain species more susceptible to extinctions based on their size and ecology? For this project, we focused on the data of marine animals. To examine the impact of size and ecology on a species's likelihood of survival, we compared the sizes and ecologies of the survivors and victims of the five mass extinctions. The ecology, or life mode, of a genus consists of the combination of tiering, motility, and feeding mechanism. Tiering refers to the animal's typical location in the water column and sediments, motility refers to its ability to move, and feeding mechanism describes the way the organism eats; together, they describe the animal's behavior. We analyzed the effect of ecology on survival using logistic regression, which compares life mode to the success or failure of a genus during each mass extinction interval. For organism size, we found the extinct organisms' mean size (both volume and length) and compared it with the average size of survivors on a graph. Our results show that while surviving genera of mass extinctions tended to be slightly larger than those that went extinct, there was no significant difference. Even though the Permian (Changhsingian) and Triassic (Rhaetian) extinctions had larger surviving species, likewise the difference was small. Ecology had a more obvious impact on the likelihood of survival; fast-moving, predatory pelagic organisms were the most likely to go extinct, while sedentary, infaunal suspension feeders had the greatest chances of survival. Overall, ecology played a greater role than size in determining the survival of a species. With this information, we can use ecology to predict which species would survive future extinctions.

  15. Size effects of latex nanomaterials on lung inflammation in mice

    International Nuclear Information System (INIS)

    Inoue, Ken-ichiro; Takano, Hirohisa; Yanagisawa, Rie; Koike, Eiko; Shimada, Akinori

    2009-01-01

    Effects of nano-sized materials (nanomaterials) on sensitive population have not been well elucidated. This study examined the effects of pulmonary exposure to (latex) nanomaterials on lung inflammation related to lipopolysaccharide (LPS) or allergen in mice, especially in terms of their size-dependency. In protocol 1, ICR male mice were divided into 8 experimental groups that intratracheally received a single exposure to vehicle, latex nanomaterials (250 μg/animal) with three sizes (25, 50, and 100 nm), LPS (75 μg/animal), or LPS plus latex nanomaterials. In protocol 2, ICR male mice were divided into 8 experimental groups that intratracheally received repeated exposure to vehicle, latex nanomaterials (100 μg/animal), allergen (ovalbumin: OVA; 1 μg/animal), or allergen plus latex nanomaterials. In protocol 1, latex nanomaterials with all sizes exacerbated lung inflammation elicited by LPS, showing an overall trend of amplified lung expressions of proinflammatory cytokines. Furthermore, LPS plus nanomaterials, especially with size less than 50 nm, significantly elevated circulatory levels of fibrinogen, macrophage chemoattractant protein-1, and keratinocyte-derived chemoattractant, and von Willebrand factor as compared with LPS alone. The enhancement tended overall to be greater with the smaller nanomaterials than with the larger ones. In protocol 2, latex nanomaterials with all sizes did not significantly enhance the pathophysiology of allergic asthma, characterized by eosinophilic lung inflammation and Igs production, although latex nanomaterials with less than 50 nm significantly induced/enhanced neutrophilic lung inflammation. These results suggest that latex nanomaterials differentially affect two types of (innate and adaptive immunity-dominant) lung inflammation

  16. Size Effect of Defects on the Mechanical Properties of Graphene

    Science.gov (United States)

    Park, Youngho; Hyun, Sangil

    2018-03-01

    Graphene, a two-dimensional material, has been studied and utilized for its excellent material properties. In reality, achieving a pure single-crystalline structure in graphene is difficult, so usually graphene may have various types of defects in it. Vacancies, Stone-Wales defects, and grain boundaries can drastically change the material properties of graphene. Graphene with vacancy defects has been of interest because it is a two-dimensional analogy of three-dimensional porous materials. It has efficient material properties, and can function as a part of modern devices. The mechanical properties have been studied by using molecular dynamics for either a single vacancy defect with various sizes or multiple vacancy defects with same defect ratios. However, it is not clear which one has more influence on the mechanical properties between the size of the defects and the defect ratio. Therefore, we investigated the hole-size effect on the mechanical properties of single-crystalline graphene at various defect ratios. A void defect with large size can have a rather high tensile modulus with a low fracture strain compared to a void defect with small size. We numerically found that the tensile properties of scattered single vacancies is similar to that of amorphous graphene. We suspect that this is due to the local orbital change of the carbon atoms near the boundary of the void defects, so-called the interfacial phase.

  17. The effect of laser unit on photodynamic therapy spot size.

    Science.gov (United States)

    Ansari-Shahrezaei, Siamak; Binder, Susanne; Stur, Michael

    2011-01-01

    To determine the effect of the laser unit on photodynamic therapy (PDT) spot size. A calibrated Gullstrand-type model eye was used for this study. The axial length of the model eye was set to different values ranging from 22.2 to 27.0 mm, and the actual spot size from the laser console was recorded for treating a spot of 4 mm in the center of the artificial fundus using two different laser units (Coherent Opal laser; Coherent Inc, Santa Clara, California, USA and Zeiss Visulas laser; Carl Zeiss Meditec Inc, Dublin, California, USA) and two indirect contact laser lenses (Volk PDT laser lens and Volk Area Centralis lens; Volk Optical Inc, Mentor, Ohio, USA). From myopia to hyperopia, the total deviation from the intended spot size was -22.5% to -7.5% (Opal laser and PDT laser lens), and -17.5% to +2.5% (Visulas laser and PDT laser lens), -12.5% to +7.5% (Opal laser and Area Centralis lens), and -7.5% to +10% (Visulas laser and Area Centralis lens). The used laser unit has a significant effect on PDT spot size in this model. These findings may be important for optimizing PDT of choroidal neovascular lesions.

  18. Size, Shape and Impurity Effects on Superconducting critical temperature.

    Science.gov (United States)

    Umeda, Masaki; Kato, Masaru; Sato, Osamu

    Bulk superconductors have their own critical temperatures Tc. However, for a nano-structured superconductor, Tc depends on size and shape of the superconductor. Nishizaki showed that the high pressure torsion on bulks of Nb makes Tc higher, because the torsion makes many nano-sized fine grains in the bulks. However the high pressure torsion on bulks of V makes Tc lower, and Nishizaki discussed that the decrease of Tc is caused by impurities in the bulks of V. We studied size, shape, and impurity effects on Tc, by solving the Gor'kov equations, using the finite element method. We found that smaller and narrower superconductors show higher Tc. We found how size and shape affects Tc by studying spacial order parameter distributions and quasi-particle eigen-energies. Also we studied the impurity effects on Tc, and found that Tc decreases with increase of scattering rate by impurities. This work was supported in part of KAKENHI Grant Number JP26400367 and JP16K05460, and program for leading graduate schools of ministry of education, culture, sports, science and technology-Japan.

  19. Finite size effects in neutron star and nuclear matter simulations

    Energy Technology Data Exchange (ETDEWEB)

    Giménez Molinelli, P.A., E-mail: pagm@df.uba.ar; Dorso, C.O.

    2015-01-15

    single structure per cell while the cubic and truncated octahedron show consistent results, with more than one structure per cell. For systems of the size studied in this work these effects are still noticeable, but we find evidence to support that the dependence of the results on the cell geometry becomes smaller as the system size is increased. When the Coulomb interaction is present, the competition between opposing interactions of different range results in a proper, physically meaningful length scale that is independent of the system size and periodic cell of choice. Only under these conditions “finite size effects” will vanish for large enough systems (i.e. cells much larger than this characteristic length). Larger simulations are in order, but our computational capabilities forbid it for the time being.

  20. Does screen size matter for smartphones? Utilitarian and hedonic effects of screen size on smartphone adoption.

    Science.gov (United States)

    Kim, Ki Joon; Sundar, S Shyam

    2014-07-01

    This study explores the psychological effects of screen size on smartphone adoption by proposing an extended Technology Acceptance Model (TAM) that integrates an empirical comparison between large and small screens with perceived control, affective quality, and the original TAM constructs. A structural equation modeling analysis was conducted on data collected from a between-subjects experiment (N=130) in which users performed a web-based task on a smartphone with either a large (5.3 inches) or a small (3.7 inches) screen. Results show that a large screen, compared to a small screen, is likely to lead to higher smartphone adoption by simultaneously promoting both the utilitarian and hedonic qualities of smartphones, which in turn positively influence perceived ease of use of-and attitude toward-the device respectively. Implications and directions for future research are discussed.

  1. Race differences in accuracy of self-reported childhood body size among white and black women

    NARCIS (Netherlands)

    Field, AE; Franko, DL; Striegel-Moore, RH; Schreiber, GB; Crawford, PB; Daniels, [No Value

    Objective: To assess the relation of self-reported current and recalled preadolescent body size to measured BMI (kilograms per meter squared) and interviewer's assessment of body size. 4Research Methods and Procedures: This was a prospective cohort study of 1890 white and black women who were 9 to

  2. Effect of particle size on mixing degree in dispensation.

    Science.gov (United States)

    Nakamura, Hitoshi; Yanagihara, Yoshitsugu; Sekiguchi, Hiroko; Ohtani, Michiteru; Kariya, Satoru; Uchino, Katsuyoshi; Suzuki, Hiroshi; Iga, Tatsuji

    2004-03-01

    By using lactose colored with erythrocin, we examined the effect of particle size on mixing degree during the preparation of triturations with a mortar and pestle. We used powders with different distributions of particle sizes, i.e., powder that passed through 32-mesh but was trapped on a 42-mesh sieve (32/42-mesh powder), powder that passed through a 42-mesh sieve but was trapped on a 60-mesh sieve (42/60-mesh powder), powder that passed through a 60-mesh sieve but was trapped on a 100-mesh sieve (60/100-mesh powder), and powder that passes through a 100-mesh sieve (> 100-mesh powder). The mixing degree of colored powder and non-colored powder whose distribution of particle sizes was the same as that of the colored powder was excellent. The coefficient of variation (CV) value of the mixing degree was 6.08% after 40 rotations when colored powder was mixed with non-colored powder that both passed through a 100-mesh sieve. The CV value of the mixing degree was low in the case of mixing of colored and non-colored powders with different particle size distributions. After mixing, about 50% of 42/60-mesh powder had become smaller particles, whereas the distribution of particle sizes was not influenced by the mixing of 60/100-mesh powder. It was suggested that the mixing degree is affected by distribution of particle sizes. It may be important to determine the mixing degrees for drugs with narrow therapeutic ranges.

  3. Effect of nanofillers' size on surface properties after toothbrush abrasion.

    Science.gov (United States)

    Cavalcante, Larissa M; Masouras, Konstantinos; Watts, David C; Pimenta, Luiz A; Silikas, Nick

    2009-02-01

    To investigate the effect of filler-particle size of experimental and commercial resin composites, undergoing toothbrush abrasion, on three surface properties: surface roughness (SR), surface gloss (G) and color stability (CS). Four model (Ivoclar/Vivadent) and one commercial resin composite (Tokuyama) with varying filler-size from 100-1000 nm were examined. Six discs (10 mm x 2 mm) from each product were prepared and mechanically polished. The samples were then submitted to 20,000 brushing strokes in a toothbrush abrasion machine. SR parameters (Ra, Rt and RSm), G, and CS were measured before and after toothbrush abrasion. Changes in SR and G were analyzed by 2-way ANOVA, with Bonferroni post hoc test. CS values were submitted to one-way ANOVA and Bonferroni post hoc test (alpha=0.05). Initial G values ranged between 73-87 gloss units (GU) and were reduced after toothbrush abrasion to a range of 8-64 GU. Toothbrush abrasion resulted in significant modifications in SR and G amongst the materials tested, attributed to filler sizes. There was statistically significant difference in color (delta E* ranged from 0.38-0.88). Filler size did not affect color stability. Toothbrush abrasion resulted in rougher and matte surfaces for all materials tested. Although the individual differences in surface roughness among filler sizes were not always significant, the correlation showed a trend that larger filler sizes resulted in higher surface roughness after abrasion for the SR parameters Ra and Rt (r = 0.95; r = 0.93, respectively). RSm showed an increase after toothbrush abrasion for all resin composites, however no significant correlation was detected (r = 0.21).There was a significant correlation between G and Ra ratios (r = - 0.95).

  4. Size effect related to damping caused by water submersion

    International Nuclear Information System (INIS)

    Dong, R.G.

    1981-01-01

    An important effect of water submersion on the dynamic response of a structure is the increase in effective damping. The dynamic response of submerged structures is of interest in the nuclear power industry for reasons of operational safety during seismic and other dynamic excitations. In this paper, the added damping contribution that results from the viscosity of water and the dependence of the contribution on structural size are examined. Other factors considered are the applicable range of viscous damping with respect to displacement amplitude and, as far as damping is concerned, how far neighboring members must be from each other to respond as if in open water. An expression is derived for relating the damping value to structural size. Estimated added-damping values for representative fuel elements, fuel bundles, and main steam-pressure-relief-valve lines are given based on our derived expression for added damping

  5. Effective source size as related to 252Cf neutron radiography

    International Nuclear Information System (INIS)

    Wada, Nobuo; Enomoto, Shigemasa; Tachikawa, Noboru; Nojiri, Toshiaki.

    1977-01-01

    The effective source size in 252 Cf thermal neutron radiography, relating to its geometrical unsharpness in image formation, is experimentally studied. A neutron radiographic system consists of a 160 μg 252 Cf neutron source, water moderator and divergent cadmium lined collimator. Thermal neutron image detection is performed with using a LiF scintillator and a high speed X-ray film to employ direct exposure method. The modulation transfer function, used for describing image quality, is derived from radiographic image corresponding to a cadmium plate with sharp edge. The modulation transfer function for the system is expressed by the product of the function for both geometrical and inherent unsharpness, and allows isolation of geometrical unsharpness as related to the effective size of the thermal neutron source. It is found to be 80 -- 90% of the collimator inlet diameter. (auth.)

  6. Effect of eating rate on binge size in Bulimia Nervosa

    Science.gov (United States)

    Kissileff, Harry R; Zimmerli, Ellen J; Torres, Migdalia I; Devlin, Michael J; Walsh, B Timothy

    2008-01-01

    Effect of eating rate on binge size in bulimia nervosa. Bulimia Nervosa (BN) is an eating disorder characterized by recurrent episodes of binge eating. During binge eating episodes, patients often describe the rapid consumption of food, and laboratory studies have shown that during binges patients with BN eat faster than normal controls (NC), but the hypothesis that a rapid rate of eating contributes to the excessive intake of binge meals has not yet been experimentally tested. The aim of this study was to assess the effect of eating rate on binge size in BN, in order to determine whether binge size is mediated, in part, by rate of eating. Thirteen BN and 14 NC subjects were asked to binge eat a yogurt shake that was served at a fast rate (140g/min) on one occasion and at a slow rate (70g/min) on another. NC subjects consumed 169 g more when eating at the fast rate than when eating at the slow rate. In contrast, consumption rates failed to influence binge size in patients with BN (fast: 1205 g; slow: 1195 g). Consequently, there was a significant group by rate interaction. As expected, patients with BN consumed more overall than NC subjects (1200 g vs. 740 g). When instructed to binge in the eating laboratory, patients with BN ate equally large amounts of food at a slow rate as at a fast rate. NC subjects ate less at a slow rate. These findings indicate that in a structured laboratory meal paradigm binge size is not affected by rate of eating. PMID:17996257

  7. Finite size effects on hydrogen bonds in confined water

    International Nuclear Information System (INIS)

    Musat, R.; Renault, J.P.; Le Caer, S.; Pommeret, S.; Candelaresi, M.; Palmer, D.J.; Righini, R.

    2008-01-01

    Femtosecond IR spectroscopy was used to study water confined in 1-50 nm pores. The results show that even large pores induce significant changes (for example excited-state lifetimes) to the hydrogen-bond network, which are independent of pore diameter between 1 and 50 nm. Thus, the changes are not surface-induced but rather finite size effects, and suggest a confinement-induced enhancement of the acidic character of water. (authors)

  8. Significant Effect of Pore Sizes on Energy Storage in Nanoporous Carbon Supercapacitors.

    Science.gov (United States)

    Young, Christine; Lin, Jianjian; Wang, Jie; Ding, Bing; Zhang, Xiaogang; Alshehri, Saad M; Ahamad, Tansir; Salunkhe, Rahul R; Hossain, Shahriar A; Khan, Junayet Hossain; Ide, Yusuke; Kim, Jeonghun; Henzie, Joel; Wu, Kevin C-W; Kobayashi, Naoya; Yamauchi, Yusuke

    2018-04-20

    Mesoporous carbon can be synthesized with good control of surface area, pore-size distribution, and porous architecture. Although the relationship between porosity and supercapacitor performance is well known, there are no thorough reports that compare the performance of numerous types of carbon samples side by side. In this manuscript, we describe the performance of 13 porous carbon samples in supercapacitor devices. We suggest that there is a "critical pore size" at which guest molecules can pass through the pores effectively. In this context, the specific surface area (SSA) and pore-size distribution (PSD) are used to show the point at which the pore size crosses the threshold of critical size. These measurements provide a guide for the development of new kinds of carbon materials for supercapacitor devices. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Influences of population size and density on birthplace effects.

    Science.gov (United States)

    Hancock, David J; Coutinho, Patrícia; Côté, Jean; Mesquita, Isabel

    2018-01-01

    Contextual influences on talent development (e.g., birthplace effects) have become a topic of interest for sport scientists. Birthplace effects occur when being born in a certain city size leads to participation or performance advantages, typically for those born in smaller or mid-sized cities. The purpose of this study was to investigate birthplace effects in Portuguese volleyball players by analysing city size, as well as population density - an important but infrequently used variable. Participants included 4062 volleyball players (M age  = 33), 53.2% of whom were men. Using Portuguese national census data from 1981, we compared participants (within each sex) across five population categories. In addition, we used ANOVAs to study expertise and population density. Results indicated that men and women athletes born in districts of 200,000-399,999 were 2.4 times more likely to attain elite volleyball status, while all other districts decreased the odds of expert development. For men, being born in high-density areas resulted in less chance of achieving expertise, whereas there were no differences for women. The results suggest that athletes' infrastructure and social structure play an important role in talent development, and that these structures are influenced by total population and population density, respectively.

  10. Size effects on magnetoelectric response of multiferroic composite with inhomogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Y.M. [Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Department of Mechanics, Shanghai University, Shanghai 200072 (China); Xu, K.Y., E-mail: kyxu@shu.edu.cn [Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Department of Mechanics, Shanghai University, Shanghai 200072 (China); Chen, T. [Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Department of Mechanics, Shanghai University, Shanghai 200072 (China); Aifantis, E.C. [Laboratory of Mechanics and Materials (LMM), Aristotle University of Thessaloniki, Thessaloniki GR-54124 (Greece); Michigan Technological University, Houghton, MI 49931 (United States); King Abdulaziz University, Jeddah 21589 (Saudi Arabia); School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu, 610031 (China); International Laboratory for Modern Functional Materials, ITMO University, St. Petersburg 191002 (Russian Federation)

    2015-12-01

    This paper investigates the influence of size effects on the magnetoelectric performance of multiferroic composite with inhomogeneities. Based on a simple model of gradient elasticity for multiferroic materials, the governing equations and boundary conditions are obtained from an energy variational principle. The general formulation is applied to consider an anti-plane problem of multiferroic composites with inhomogeneities. This problem is solved analytically and the effective magnetoelectric coefficient is obtained. The influence of the internal length (grain size or particle size) on the effective magnetoelectric coefficients of piezoelectric/piezomagnetic nanoscale fibrous composite is numerically evaluated and analyzed. The results suggest that with the increase of the internal length of piezoelectric matrix (PZT and BaTiO{sub 3}), the magnetoelectric coefficient increases, but the rate of increase is ratcheting downwards. If the internal length of piezoelectric matrix remains unchanged, the magnetoelectric coefficient will decrease with the increase of internal length scale of piezomagnetic nonfiber (CoFe{sub 2}O{sub 3}). In a composite consisiting of a piezomagnetic matrix (CoFe{sub 2}O{sub 3}) reinforced with piezoelectric nanofibers (BaTiO{sub 3}), an increase of the internal length in the piezomagnetic matrix, results to a decrease of the magnetoelectric coefficient, with the rate of decrease diminishing.

  11. Size effects on magnetoelectric response of multiferroic composite with inhomogeneities

    Science.gov (United States)

    Yue, Y. M.; Xu, K. Y.; Chen, T.; Aifantis, E. C.

    2015-12-01

    This paper investigates the influence of size effects on the magnetoelectric performance of multiferroic composite with inhomogeneities. Based on a simple model of gradient elasticity for multiferroic materials, the governing equations and boundary conditions are obtained from an energy variational principle. The general formulation is applied to consider an anti-plane problem of multiferroic composites with inhomogeneities. This problem is solved analytically and the effective magnetoelectric coefficient is obtained. The influence of the internal length (grain size or particle size) on the effective magnetoelectric coefficients of piezoelectric/piezomagnetic nanoscale fibrous composite is numerically evaluated and analyzed. The results suggest that with the increase of the internal length of piezoelectric matrix (PZT and BaTiO3), the magnetoelectric coefficient increases, but the rate of increase is ratcheting downwards. If the internal length of piezoelectric matrix remains unchanged, the magnetoelectric coefficient will decrease with the increase of internal length scale of piezomagnetic nonfiber (CoFe2O3). In a composite consisiting of a piezomagnetic matrix (CoFe2O3) reinforced with piezoelectric nanofibers (BaTiO3), an increase of the internal length in the piezomagnetic matrix, results to a decrease of the magnetoelectric coefficient, with the rate of decrease diminishing.

  12. Blade size and weight effects in shovel design.

    Science.gov (United States)

    Freivalds, A; Kim, Y J

    1990-03-01

    The shovel is a basic tool that has undergone only nominal systematic design changes. Although previous studies found shovel-weight and blade-size effects of shovelling, the exact trade-off between the two has not been quantified. Energy expenditure, heart rate, ratings of perceived exertion and shovelling performance were measured on five subjects using five shovels with varying blade sizes and weights to move sand. Energy expenditure, normalised to subject weight and load handled, varied quadratically with the blade-size/shovel-weight (B/W) ratio. Minimum energy cost was at B/W = 0.0676 m2/kg, which for an average subject and average load would require an acceptable 5.16 kcal/min of energy expenditure. Subjects, through the ratings of perceived exertion, also strongly preferred the lighter shovels without regard to blade size. Too large a blade or too heavy a shovel increased energy expenditure beyond acceptable levels, while too small a blade reduced efficiency of the shovelling.

  13. Size effects on free vibration of heterogeneous beams

    Directory of Open Access Journals (Sweden)

    Hassanati Bahman

    2018-01-01

    Full Text Available In this paper the influence of microstructure on the free vibration of geometrically similar heterogeneous beams with free-free boundary conditions was numerically investigated by detailed finite element analysis (FEA to identify and quantify any effect of beam size on transverse modal frequencies when the microstructural scale is comparable to the overall size. ANSYS Mechanical APDL was used to generate specific unit cells at the microstructural scale comprised of two isotropic materials with different material properties. Unit cell variants containing voids and inclusions were considered. At the macroscopic scale, four beam sizes consisting of one, two, three or four layers of defined unit cells were represented by repeatedly regenerating the unit cell as necessary. In all four beam sizes the aspect ratio was kept constant. Changes to the volume fractions of each material were introduced while keeping the homogenized properties of the beam fixed. The influence of the beam surface morphology on the results was also investigated. The ANSYS results were compared with the analytical results from solution to Timoshenko beam and nonlocal Timoshenko beam as well as numerical results for a Micropolar beam. In nonlocal Timoshenko beams the Eringen’s small length scale coefficients were estimated for some of the studied models. Numerical analyses based on Micropolar theory were carried out to study the modal frequencies and a method was suggested to estimate characteristic length in bending and coupling number via transverse vibration which verifies the use of Micropolar elasticity theory in dynamic analysis.

  14. [The effect of disinfectant soaking on dental gypsum model size].

    Science.gov (United States)

    Zhu, Cao-yun; Xu, Yun-wen; Xu, Kan

    2012-12-01

    To study the influence of disinfectant soaking on the dimensional stability of three kinds of dental gypsum model. Three commonly used gypsums ( type III,IV,Vtype) in clinic were used to make 24 specimens for 50 mm×15 mm×10 mm in size. One hour after release, the specimens were placed for 24 h. A digital caliper was used to measure the size of the gypsum model. Distilled water immersion was as used control, glutaraldehyde disinfectant and Metrix CaviCide disinfectant soaking were used for the experimental group. After soaking for 0.5h, the gypsum models were removed and placed for 0.5 h, 1 h, 2 h, 24 h. The size of the models was measured again using the same method. The data was analyzed with SPSS10.0 software package. The initial gypsum model length was (50.07±0.017) mm, (50.048±0.015) mm and (50.027±0.015) mm. After soaking for different times, the size of the model changed little, and the dimensions changed less than 0.01%. The results show that disinfectant soaking has no significant effect on dental model dimensions.

  15. Effect of geometric base roughness on size segregation

    Directory of Open Access Journals (Sweden)

    Jing L.

    2017-01-01

    Full Text Available The geometric roughness at boundaries has a profound impact on the dynamics of granular flows. For a bumpy base made of fixed particles, two major factors have been separately studied in the literature, namely, the size and spatial distribution of base particles. A recent work (Jing et al. 2016 has proposed a roughness indicator Ra, which combines both factors for any arbitrary bumpy base comprising equally-sized spheres. It is shown in mono-disperse flows that as Ra increases, a transition occurs from slip (Ra 0.62 conditions. This work focuses on such a phase transition in bi-disperse flows, in which Ra can be a function of time. As size segregation takes place, large particles migrate away from the bottom, leading to a variation of size ratio between flow- and base-particles. As a result, base roughness Ra evolves with the progress of segregation. Consistent with the slip/non-slip transition in mono-disperse flows, basal sliding arises at low values of Ra and the development of segregation might be affected; when Ra increases to a certain level (Ra > 0.62, non-slip condition is respected. This work extends the validity of Ra to bi-disperse flows, which can be used to understand the geometric boundary effect during segregation.

  16. Electric field engineering using quantum-size-effect-tuned heterojunctions

    KAUST Repository

    Adinolfi, V.

    2013-07-03

    A quantum junction solar cell architecture was recently reported that employs colloidal quantum dots (CQDs) on each side of the p-n junction. This architecture extends the range of design opportunities for CQD photovoltaics, since the bandgap can be tuned across the light-absorbing semiconductor layer via control over CQD size, employing solution-processed, room-temperature fabricated materials. We exploit this feature by designing and demonstrating a field-enhanced heterojunction architecture. We optimize the electric field profile within the solar cell through bandgap engineering, thereby improving carrier collection and achieving an increased open circuit voltage, resulting in a 12% improvement in power conversion efficiency.

  17. Intraspecific variation in egg size and egg composition in birds: effects on offspring fitness.

    Science.gov (United States)

    Williams, T D

    1994-02-01

    1. There is little unequivocal evidence to date in support of a positive relationship between egg size and offspring fitness in birds. Although 40 studies (of 34 species) have considered the effect of variation in egg size on chick growth and/or survival up to fledgling only 12 studies have controlled for other characters potentially correlated both with egg size and offspring fitness. Of these only two have reported a significant residual effect of egg size on chick growth (in the roseate tern and European blackbird) and three a residual effect on chick survival (all in seabirds: common tern, lesser black-backed gull and kittiwake). 2. More consistent evidence exists, though from fewer studies, for a positive relationship between egg size and offspring fitness early in the chick-rearing period; chick growth and chick survival being dependent on egg size in 8 of 10 studies and 4 of 5 studies respectively. It is suggested that the most important effect of variation in egg size might be in determining the probability of offspring survival in the first few days after hatching. 3. Egg size explains on average 66% of the variation in chick mass at hatching (n = 35 studies) but only 30% of the variation in chick body size (n = 18). When effects of hatching body size are controlled for chick mass remains significantly correlated with egg size, though the reverse is not true. This supports the hypothesis that large eggs give rise to heavier chicks at hatching, i.e., chicks with more nutrient (yolk) reserves, rather than structurally larger chicks. 4. Egg composition increased isometrically with increasing egg size in about half the studies so far reported (n equals approximately 20). However, in seabirds, and some passerines, larger eggs contain disproportionately more albumen, whilst in some waterfowl percentage yolk content increases with increasing egg size. Changes in albumen content largely reflect variation in the water content of eggs, but changes in yolk content

  18. Analyzing ROC curves using the effective set-size model

    Science.gov (United States)

    Samuelson, Frank W.; Abbey, Craig K.; He, Xin

    2018-03-01

    The Effective Set-Size model has been used to describe uncertainty in various signal detection experiments. The model regards images as if they were an effective number (M*) of searchable locations, where the observer treats each location as a location-known-exactly detection task with signals having average detectability d'. The model assumes a rational observer behaves as if he searches an effective number of independent locations and follows signal detection theory at each location. Thus the location-known-exactly detectability (d') and the effective number of independent locations M* fully characterize search performance. In this model the image rating in a single-response task is assumed to be the maximum response that the observer would assign to these many locations. The model has been used by a number of other researchers, and is well corroborated. We examine this model as a way of differentiating imaging tasks that radiologists perform. Tasks involving more searching or location uncertainty may have higher estimated M* values. In this work we applied the Effective Set-Size model to a number of medical imaging data sets. The data sets include radiologists reading screening and diagnostic mammography with and without computer-aided diagnosis (CAD), and breast tomosynthesis. We developed an algorithm to fit the model parameters using two-sample maximum-likelihood ordinal regression, similar to the classic bi-normal model. The resulting model ROC curves are rational and fit the observed data well. We find that the distributions of M* and d' differ significantly among these data sets, and differ between pairs of imaging systems within studies. For example, on average tomosynthesis increased readers' d' values, while CAD reduced the M* parameters. We demonstrate that the model parameters M* and d' are correlated. We conclude that the Effective Set-Size model may be a useful way of differentiating location uncertainty from the diagnostic uncertainty in medical

  19. Group-size effect on scanning behaviour of Maasai Ostrich Struthio ...

    African Journals Online (AJOL)

    Group-size effect on scanning behaviour of Maasai Ostrich Struthio camelus ... minute) among different group sizes in late 2006 in Serengeti National Park, ... be influenced by factors other than group size, such as body size and habitat type.

  20. Size-dependent nonlocal effects in plasmonic semiconductor particles

    DEFF Research Database (Denmark)

    Maack, Johan Rosenkrantz; Mortensen, N. Asger; Wubs, Martijn

    2017-01-01

    Localized surface plasmons (LSP) in semiconductor particles are expected to exhibit spatial nonlocal response effects as the geometry enters the nanometer scale. To investigate these nonlocal effects, we apply the hydrodynamic model to nanospheres of two different semiconductor materials: intrinsic...... InSb and n-doped GaAs. Our results show that the semiconductors indeed display nonlocal effects, and that these effects are even more pronounced than in metals. In a 150 nm InSb particle at 300 K, the LSP frequency is blueshifted 35%, which is orders of magnitude larger than the blueshift in a metal...... particle of the same size. This property, together with their tunability, makes semiconductors a promising platform for experiments in nonlocal effects. Copyright (C)EPLA, 2017...

  1. Beam size effects in the radiative Bhabha scattering

    International Nuclear Information System (INIS)

    Szczekowski, M.

    1990-01-01

    In some electromagnetic processes the measured cross section can be substantially smaller than calculated in standard Quantum Electrodynamics. The process of single bremsstrahlung, e + e - → e + e - γ is an example of such effect. If the size of the effect for large angle γ radiation is similar to its magnitude at low angles, then standard calculations of the radiative Bahbha background to e.g. the reaction used in counting the number of neutrino generations, e + e - → νν-barγ, at LEP energies can be overestimated by 10-20%. 5 refs., 5 figs. (author)

  2. Size effects in PbTiO3 nanocrystals: Effect of particle size on spontaneous polarization and strains

    Science.gov (United States)

    Akdogan, E. K.; Rawn, C. J.; Porter, W. D.; Payzant, E. A.; Safari, A.

    2005-04-01

    The spontaneous polarization (Ps) and spontaneous strains (xi) in mechanically unclamped and surface charge compensated PbTiO3 nanocrystals were determined as a function of particle size in the range <150nm by differential scanning calorimetry and x-ray powder diffraction, respectively. Significant deviations from bulk order parameters (P,xi) have been observed as the particle size decreased below ˜100nm. The critical size (rc) below which the ferroelectric tetragonal phase transforms to the paraelectric cubic phase was determined as ˜15nm. The depression in transition temperature with particle size is 14 °C at 28 nm. No change in the order of m3m →4mm ferrodistortive phase transition is observed. A simple analysis showed that ΔHtr/(kBT )˜103 at 25 °C for r =16nm, indicating that the stabilization of the cubic phase at rc cannot be linked to an instability in dipolar ordering due to thermal agitations. Comparison of the spontaneous volumetric strains with the strain induced by surface stress indicated that the effect of surface stress on ferroelectric phase stability was negligible. Anomalies in electrostrictive properties were determined for r →rc. The observed size dependence of PS is attributed to the reduced extent of long-range dipole-dipole interactions that arise due to the changes in bonding characteristics of ions with decreasing particle size in the perovskite lattice, in conformity with a recent study by Tsunekawa et al. [Phys. Rev. Lett. 85 (16), 4340 (2000)].

  3. [Electronic and structural properties of individual nanometer-size supported metallic clusters]. Final performance report

    Energy Technology Data Exchange (ETDEWEB)

    Reifenberger, R.

    1993-09-01

    This report summarizes the work performed under contract DOE-FCO2-84ER45162. During the past ten years, our study of electron emission from laser-illuminated field emission tips has taken on a broader scope by addressing problems of direct interest to those concerned with the unique physical and chemical properties of nanometer-size clusters. The work performed has demonstrated that much needed data can be obtained on individual nanometer-size clusters supported on a wide-variety of different substrates. The work was performed in collaboration with R.P. Andres in the School of Chemical Engineering at Purdue University. The Multiple Expansion Cluster Source developed by Andres and his students was essential for producing the nanometer-size clusters studied. The following report features a discussion of these results. This report provides a motivation for studying the properties of nanometer-size clusters and summarizes the results obtained.

  4. Finite size effects in simulations of protein aggregation.

    Directory of Open Access Journals (Sweden)

    Amol Pawar

    Full Text Available It is becoming increasingly clear that the soluble protofibrillar species that proceed amyloid fibril formation are associated with a range of neurodegenerative disorders such as Alzheimer's and Parkinson diseases. Computer simulations of the processes that lead to the formation of these oligomeric species are starting to make significant contributions to our understanding of the determinants of protein aggregation. We simulate different systems at constant concentration but with a different number of peptides and we study the how the finite number of proteins affects the underlying free energy of the system and therefore the relative stability of the species involved in the process. If not taken into account, this finite size effect can undermine the validity of theoretical predictions regarding the relative stability of the species involved and the rates of conversion from one to the other. We discuss the reasons that give rise to this finite size effect form both a probabilistic and energy fluctuations point of view and also how this problem can be dealt by a finite size scaling analysis.

  5. Effect of supercritical fluid density on nanoencapsulated drug particle size using the supercritical antisolvent method.

    Science.gov (United States)

    Kalani, Mahshid; Yunus, Robiah

    2012-01-01

    The reported work demonstrates and discusses the effect of supercritical fluid density (pressure and temperature of supercritical fluid carbon dioxide) on particle size and distribution using the supercritical antisolvent (SAS) method in the purpose of drug encapsulation. In this study, paracetamol was encapsulated inside L-polylactic acid, a semicrystalline polymer, with different process parameters, including pressure and temperature, using the SAS process. The morphology and particle size of the prepared nanoparticles were determined by scanning electron microscopy and transmission electron microscopy. The results revealed that increasing temperature enhanced mean particle size due to the plasticizing effect. Furthermore, increasing pressure enhanced molecular interaction and solubility; thus, particle size was reduced. Transmission electron microscopy images defined the internal structure of nanoparticles. Thermal characteristics of nanoparticles were also investigated via differential scanning calorimetry. Furthermore, X-ray diffraction pattern revealed the changes in crystallinity structure during the SAS process. In vitro drug release analysis determined the sustained release of paracetamol in over 4 weeks.

  6. Effects of picture size reduction and blurring on emotional engagement.

    Directory of Open Access Journals (Sweden)

    Andrea De Cesarei

    Full Text Available The activity of basic motivational systems is reflected in emotional responses to arousing stimuli, such as natural pictures. The manipulation of picture properties such as size or detail allows for investigation into the extent to which separate emotional reactions are similarly modulated by perceptual changes, or, rather, may subserve different functions. Pursuing this line of research, the present study examined the effects of two types of perceptual degradation, namely picture size reduction and blurring, on emotional responses. Both manipulations reduced picture relevance and dampened affective modulation of skin conductance, possibly because of a reduced action preparation in response to degraded or remote pictures. However, the affective modulation of the startle reflex did not vary with picture degradation, suggesting that the identification of these degraded affective cues activated the neural circuits mediating appetitive or defensive motivation.

  7. Asteroid collisional history - Effects on sizes and spins

    International Nuclear Information System (INIS)

    Davis, D.R.; Weidenschilling, S.J.; Farinella, P.; Paolicchi, P.; Binzel, R.P.

    1989-01-01

    The effects of asteroid collisional history on sizes and spins of present-day objects are discussed. Collisional evolution studies indicate that collisions have altered the spin-rates of small bodies, but that the largest asteroids may have retained their primordial rotation rates. Most asteroids larger than 100 km diam have probably been shattered, but have gravitationally recaptured their fragments to form a rubble-pile structure. Large angular momentum asteroids appear to have Maclaurian spheroidal or Jacobi-ellipsoid-like shapes; some of them may have fissioned into binaries. An integrated size and spin collisional evolution model is presented, with two critical parameters: one which determines the spin rates for small fragments resulting from a shattering collision, and the other determines the fraction of impact angular momentum that is retained by the target. 36 refs

  8. Fast and accurate determination of modularity and its effect size

    International Nuclear Information System (INIS)

    Treviño, Santiago III; Nyberg, Amy; Bassler, Kevin E; Del Genio, Charo I

    2015-01-01

    We present a fast spectral algorithm for community detection in complex networks. Our method searches for the partition with the maximum value of the modularity via the interplay of several refinement steps that include both agglomeration and division. We validate the accuracy of the algorithm by applying it to several real-world benchmark networks. On all these, our algorithm performs as well or better than any other known polynomial scheme. This allows us to extensively study the modularity distribution in ensembles of Erdős–Rényi networks, producing theoretical predictions for means and variances inclusive of finite-size corrections. Our work provides a way to accurately estimate the effect size of modularity, providing a z-score measure of it and enabling a more informative comparison of networks with different numbers of nodes and links. (paper)

  9. Measures of effect size for chi-squared and likelihood-ratio goodness-of-fit tests.

    Science.gov (United States)

    Johnston, Janis E; Berry, Kenneth J; Mielke, Paul W

    2006-10-01

    A fundamental shift in editorial policy for psychological journals was initiated when the fourth edition of the Publication Manual of the American Psychological Association (1994) placed emphasis on reporting measures of effect size. This paper presents measures of effect size for the chi-squared and the likelihood-ratio goodness-of-fit statistic tests.

  10. Effects of high repetition rate and beam size on hard tissue damage due to subpicosecond laser pulses

    International Nuclear Information System (INIS)

    Kim, Beop-Min; Feit, Michael D.; Rubenchik, Alexander M.; Joslin, Elizabeth J.; Eichler, Juergen; Stoller, Patrick C.; Da Silva, Luiz B.

    2000-01-01

    We report the effects of the repetition rate and the beam size on the threshold for ultrashort laser pulse induced damage in dentin. The observed results are explained as cumulative thermal effects. Our model is consistent with the experimental results and explains the dependence of the threshold on repetition rate, beam size, and exposure time. (c) 2000 American Institute of Physics

  11. Controlling atomistic processes on Pb films via quantum size effects and lattice rotation

    Energy Technology Data Exchange (ETDEWEB)

    Binz, Steven [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    The two main techniques used to record the data in this dissertation were Spot Profile Analysis - Low Energy Electron Diffraction (SPA-LEED) and Scanning Tunneling Microscopy (STM). A specific data analysis technique for LEED data called G(S) curves is described in depth. G(S) curves can provide a great deal of structural information about the surface; including step heights, island size, and island separation. The effects of quantum size effects (QSE) on the diffusion and critical island sizes of Pb and In on Pb films are reported. Pb depositions on the 2D In phases {radical}3 and {radical}31 to see how the phases affect the Pb growth and its strong QSE are reported.

  12. Effect of particle size on degree of inversion in ferrites

    International Nuclear Information System (INIS)

    Siddique, M.; Butt, N.M.

    2012-01-01

    Ferrites with the spinel structure are important materials because of their structural, magnetic and electrical properties. The suitability of these materials depends on both the intrinsic behavior of the material and the effects of the grain size. Moessbauer spectroscopy was employed to investigate the cation distribution and degree of inversion in bulk and nano sized particles of CuFe/sub 2/O/sub 4/, MnFe/sub 2/O/sub 4/ and NiFe/sub 2/O/sub 4/ ferrites. The Moessbauer spectra of all bulk ferrites showed complete magnetic behavior, whereas nanoparticle ferrites showed combination of ferromagnetic and superparamagnetic components. Moreover, the cation distribution in nanoparticle materials was also found to be different to that of their bulk counterparts indicating the particle size dependency. The inversion of Cu and Ni ions in bulk sample was greater than that of nanoparticles; whereas the inversion of Mn ions was less in bulk material as compared to the nanoparticles. Hence the degree of inversion decreased in CuFe/sub 2/O/sub 4/ and NiFe/sub 2/O/sub 4/ samples whereas, it increased in MnFe/sub 2/O/sub 4/ as the particle size decreased and thus showed the anomalous behavior in this case. The nanoparticle samples also showed paramagnetic behaviour due to superparamagnetism and this effect is more prominent in MnFe/sub 2/O/sub 4/. Moessbauer spectra of bulk and nanoparticles CuFe/sub 2/O/sub 4/ is shown. (Orig./A.B.)

  13. The Power of Low Back Pain Trials: A Systematic Review of Power, Sample Size, and Reporting of Sample Size Calculations Over Time, in Trials Published Between 1980 and 2012.

    Science.gov (United States)

    Froud, Robert; Rajendran, Dévan; Patel, Shilpa; Bright, Philip; Bjørkli, Tom; Eldridge, Sandra; Buchbinder, Rachelle; Underwood, Martin

    2017-06-01

    A systematic review of nonspecific low back pain trials published between 1980 and 2012. To explore what proportion of trials have been powered to detect different bands of effect size; whether there is evidence that sample size in low back pain trials has been increasing; what proportion of trial reports include a sample size calculation; and whether likelihood of reporting sample size calculations has increased. Clinical trials should have a sample size sufficient to detect a minimally important difference for a given power and type I error rate. An underpowered trial is one within which probability of type II error is too high. Meta-analyses do not mitigate underpowered trials. Reviewers independently abstracted data on sample size at point of analysis, whether a sample size calculation was reported, and year of publication. Descriptive analyses were used to explore ability to detect effect sizes, and regression analyses to explore the relationship between sample size, or reporting sample size calculations, and time. We included 383 trials. One-third were powered to detect a standardized mean difference of less than 0.5, and 5% were powered to detect less than 0.3. The average sample size was 153 people, which increased only slightly (∼4 people/yr) from 1980 to 2000, and declined slightly (∼4.5 people/yr) from 2005 to 2011 (P pain trials and the reporting of sample size calculations may need to be increased. It may be justifiable to power a trial to detect only large effects in the case of novel interventions. 3.

  14. No Effect of Featural Attention on Body Size Aftereffects

    Directory of Open Access Journals (Sweden)

    Ian David Stephen

    2016-08-01

    Full Text Available Prolonged exposure to images of narrow bodies has been shown to induce a perceptual aftereffect, such that observers’ point of subjective normality (PSN for bodies shifts towards narrower bodies. The converse effect is shown for adaptation to wide bodies. In low-level stimuli, object attention (attention directed to the object and spatial attention (attention directed to the location of the object have been shown to increase the magnitude of visual aftereffects, while object-based attention enhances the adaptation effect in faces. It is not known whether featural attention (attention directed to a specific aspect of the object affects the magnitude of adaptation effects in body stimuli. Here, we manipulate the attention of Caucasian observers to different featural information in body images, by asking them to rate the fatness or sex typicality of male and female bodies manipulated to appear fatter or thinner than average. PSNs for body fatness were taken at baseline and after adaptation, and a change in PSN (ΔPSN was calculated. A body size adaptation effect was found, with observers who viewed fat bodies showing an increased PSN, and those exposed to thin bodies showing a reduced PSN. However, manipulations of featural attention to body fatness or sex typicality produced equivalent results, suggesting that featural attention may not affect the strength of the body size aftereffect.

  15. Finite-size effects on multibody neutrino exchange

    CERN Document Server

    Abada, A; Rodríguez-Quintero, J; Abada, As

    1998-01-01

    The effect of multibody massless neutrino exchanges between neutrons inside a finite-size neutron star is studied. We use an effective Lagrangian, which incorporates the effect of the neutrons on the neutrinos. Following Schwinger, it is shown that the total interaction energy density is computed by comparing the zero point energy of the neutrino sea with and without the star. It has already been shown that in an infinite-size star the total energy due to neutrino exchange vanishes exactly. The opposite claim that massless neutrino exchange would produce a huge energy is due to an improper summation of an infrared-divergent quantity. The same vanishing of the total energy has been proved exactly in the case of a finite star in a one-dimensional toy model. Here we study the three-dimensional case. We first consider the effect of a sharp star border, assumed to be a plane. We find that there is a non- vanishing of the zero point energy density difference between the inside and the outside due to the refraction ...

  16. Size-effect features on the magnetothermopower of bismuth nanowires

    International Nuclear Information System (INIS)

    Condrea, E.; Nicorici, A.

    2011-01-01

    Full text: In this work we have studied the magnetic field dependence of the thermopower (TEP) and resistance of glass-coated Bi wires with diameter (d) from 100 nm to at 1.5 μm below 80 K. Nanowires have anomalously large values of the thermopower (+100 μV K.1) and relatively high effective resistivities, but their frequencies of SdH oscillations remain those of bulk Bi. The TEP stays positive in longitudinal magnetic fields up to 15 T, where the surface scattering of charge carriers is negligible. Our analysis shows that the anomalous thermopower has a diffusion origin and is a consequence of the microstructure rather than the result of the strong scattering of electrons by the wire walls. The intensities of field at which the size-effect features appear on the magnetothermopower curves correspond to a value at which the diameter of the hole cyclotron orbit equals d. Size-effect features were observed only for set of nanowires with d = 100-350 nm, where diffusion TEP is dominant. The contribution of the phonon-drag effect was observed in a wire with diameter larger than 400 nm and becomes dominant at diameter of 1 μm. (authors)

  17. No Effect of Featural Attention on Body Size Aftereffects.

    Science.gov (United States)

    Stephen, Ian D; Bickersteth, Chloe; Mond, Jonathan; Stevenson, Richard J; Brooks, Kevin R

    2016-01-01

    Prolonged exposure to images of narrow bodies has been shown to induce a perceptual aftereffect, such that observers' point of subjective normality (PSN) for bodies shifts toward narrower bodies. The converse effect is shown for adaptation to wide bodies. In low-level stimuli, object attention (attention directed to the object) and spatial attention (attention directed to the location of the object) have been shown to increase the magnitude of visual aftereffects, while object-based attention enhances the adaptation effect in faces. It is not known whether featural attention (attention directed to a specific aspect of the object) affects the magnitude of adaptation effects in body stimuli. Here, we manipulate the attention of Caucasian observers to different featural information in body images, by asking them to rate the fatness or sex typicality of male and female bodies manipulated to appear fatter or thinner than average. PSNs for body fatness were taken at baseline and after adaptation, and a change in PSN (ΔPSN) was calculated. A body size adaptation effect was found, with observers who viewed fat bodies showing an increased PSN, and those exposed to thin bodies showing a reduced PSN. However, manipulations of featural attention to body fatness or sex typicality produced equivalent results, suggesting that featural attention may not affect the strength of the body size aftereffect.

  18. Effect size calculation in meta-analyses of psychotherapy outcome research.

    Science.gov (United States)

    Hoyt, William T; Del Re, A C

    2018-05-01

    Meta-analysis of psychotherapy intervention research normally examines differences between treatment groups and some form of comparison group (e.g., wait list control; alternative treatment group). The effect of treatment is normally quantified as a standardized mean difference (SMD). We describe procedures for computing unbiased estimates of the population SMD from sample data (e.g., group Ms and SDs), and provide guidance about a number of complications that may arise related to effect size computation. These complications include (a) incomplete data in research reports; (b) use of baseline data in computing SMDs and estimating the population standard deviation (σ); (c) combining effect size data from studies using different research designs; and (d) appropriate techniques for analysis of data from studies providing multiple estimates of the effect of interest (i.e., dependent effect sizes). Clinical or Methodological Significance of this article: Meta-analysis is a set of techniques for producing valid summaries of existing research. The initial computational step for meta-analyses of research on intervention outcomes involves computing an effect size quantifying the change attributable to the intervention. We discuss common issues in the computation of effect sizes and provide recommended procedures to address them.

  19. Body Size Predicts Cardiac and Vascular Resistance Effects on Men's and Women's Blood Pressure

    Directory of Open Access Journals (Sweden)

    Joyce M. Evans

    2017-08-01

    Full Text Available Key Points SummaryWe report how blood pressure, cardiac output and vascular resistance are related to height, weight, body surface area (BSA, and body mass index (BMI in healthy young adults at supine rest and standing.Much inter-subject variability in young adult's blood pressure, currently attributed to health status, may actually result from inter-individual body size differences.Each cardiovascular variable is linearly related to height, weight and/or BSA (more than to BMI.When supine, cardiac output is positively related, while vascular resistance is negatively related, to body size. Upon standing, the change in vascular resistance is positively related to size.The height/weight relationships of cardiac output and vascular resistance to body size are responsible for blood pressure relationships to body size.These basic components of blood pressure could help distinguish normal from abnormal blood pressures in young adults by providing a more effective scaling mechanism.Introduction: Effects of body size on inter-subject blood pressure (BP variability are not well established in adults. We hypothesized that relationships linking stroke volume (SV, cardiac output (CO, and total peripheral resistance (TPR with body size would account for a significant fraction of inter-subject BP variability.Methods: Thirty-four young, healthy adults (19 men, 15 women participated in 38 stand tests during which brachial artery BP, heart rate, SV, CO, TPR, and indexes of body size were measured/calculated.Results: Steady state diastolic arterial BP was not significantly correlated with any index of body size when subjects were supine. However, upon standing, the more the subject weighed, or the taller s/he was, the greater the increase in diastolic pressure. Systolic pressure strongly correlated with body weight and height both supine and standing. Diastolic and systolic BP were more strongly related to height, weight and body surface area than to body mass

  20. Polymer-Particle Nanocomposites: Size and Dispersion Effects

    Science.gov (United States)

    Moll, Joseph

    also addresses the interfacial, rigid polymer layer, or 'bound layer' which has long been of interest in polymer nanocomposites and polymer thin films. The divergent properties of the 'bound layer' as compared to the bulk material can have very important effects on properties, including mechanical properties. This is especially true in polymer nanocomposites, where at high weight fractions, 'bound layer' polymer can easily make up 20% or more of total material! Here we quantify this layer of bound polymer as a function of particle size, polymer molecular weight and other variables, primarily using thermogravimetric analysis but also dynamic light scattering and differential scanning calorimetry. We find that as nanoparticles become smaller, the 'bound layer' systematically decreases in thickness. This result is quite relevant to explanations of many polymer nanocomposite properties that depend on size, including mechanical and barrier properties. Many additional important and new results are reported herein. These include the importance of dispersion state in the resulting mechanical properties of polymer-particle nanocomposites, where a systematic study showed an optimal dispersion state of a connected particle network. An additional and unexpected finding in this system was the critical dependence of composite properties on grafted chain length of particles. As the grafted chain length is increased, the strain which leads to yielding in a steady shear experiment is increased in a linear relationship. At very high rates, this yielding process completely switches mechanisms, from yielding of the particle network to yielding of the entangled polymer network! A surprising correlation between the amount of bound polymer in solution and in the bulk was also found and is interpreted herein. Self-assembly was further explored in a range of different systems and it was found that grafted particles and there mimics have vast potential in the creation of a wide array of

  1. The Effect of Family Size on Incentive Effects of Welfare Transfers in Two-Parent Families

    Science.gov (United States)

    Lewin, Alisa C.; Maurin, Eric

    2005-01-01

    Family size is an important determinant of family well-being, and it is a good predictor of poverty. This study examines effects of waiving the 100-hour rule, by family size, and distinguishes between the "work-incentive effects" and the "eligibility effects" of the waiver. The 100-hour rule limits eligibility to aid to…

  2. Size Effect Studies on Tensile Tests for Hot Stamping Steel

    Science.gov (United States)

    Chen, Xiaodu; Li, Yuanyuan; Han, Xianhong; Zhang, Junbo

    2018-02-01

    Tensile tests have been widely used to determine basic mechanical properties of materials. However, the properties measured may be related to geometrical factors of the tested samples especially for high-strength steels; this makes the properties' definitions and comparisons difficult. In this study, a series of tensile tests of ultra-high-strength hot-stamped steel were performed; the geometric shapes and sizes as well as the cutting direction were modified. The results demonstrate that the hot-stamped parts were isotropic and the cutting direction had no effect; the measured strengths were practically unrelated to the specimen geometries, including both size and shape. The elongations were slightly related to sample sizes within the studied range but highly depended on the sample shape, represented by the coefficient K. Such phenomena were analyzed and discussed based on microstructural observations and fracture morphologies. Moreover, two widely used elongation conversion equations, the Oliver formula and Barba's law, were introduced to verify their applicability, and a new interpolating function was developed and compared.

  3. Effect of cuprous oxide with different sizes on thermal and combustion behaviors of unsaturated polyester resin.

    Science.gov (United States)

    Hou, Yanbei; Hu, Weizhao; Gui, Zhou; Hu, Yuan

    2017-07-15

    Cuprous oxide (Cu 2 O) as an effective catalyst has been applied to enhance the fire safety of unsaturated polyester resin (UPR), but the particle size influence on combustion behaviors has not been previously reported. Herein, the UPR/Cu 2 O composites (metal oxide particles with average particle-size of 10, 100, and 200nm) were successfully synthesized by thermosetting process. The effects of Cu 2 O with different sizes on thermostability and combustion behaviors of UPR were characterized by TGA, MCC, TG-IR, FTIR, and SSTF. The results revel that the addition of Cu 2 O contributes to sufficient decomposition of oxygen-containing compounds, which is beneficial to the release of nontoxic compounds. The smallest-sized Cu 2 O performs the excellent catalytic decomposition effect and promotes the complete combustion of UPR, which benefits the enhancement of fire safety. While the other additives retard pyrolysis process and yield more char residue, and thus the flame retardancy of UPR composites was improved. Therefore, catalysis plays a major role for smaller-sized particles during thermal decomposition of matrix, while flame retarded effect became gradual distinctly for the larger-sized additives. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. The effect of nanocrystalline magnetite size on arsenic removal

    Directory of Open Access Journals (Sweden)

    J.T. Mayo et al

    2007-01-01

    Full Text Available Higher environmental standards have made the removal of arsenic from water an important problem for environmental engineering. Iron oxide is a particularly interesting sorbent to consider for this application. Its magnetic properties allow relatively routine dispersal and recovery of the adsorbent into and from groundwater or industrial processing facilities; in addition, iron oxide has strong and specific interactions with both As(III and As(V. Finally, this material can be produced with nanoscale dimensions, which enhance both its capacity and removal. The objective of this study is to evaluate the potential arsenic adsorption by nanoscale iron oxides, specifically magnetite (Fe3O4 nanoparticles. We focus on the effect of Fe3O4 particle size on the adsorption and desorption behavior of As(III and As(V. The results show that the nanoparticle size has a dramatic effect on the adsorption and desorption of arsenic. As particle size is decreased from 300 to 12 nm the adsorption capacities for both As(III and As(V increase nearly 200 times. Interestingly, such an increase is more than expected from simple considerations of surface area and suggests that nanoscale iron oxide materials sorb arsenic through different means than bulk systems. The desorption process, however, exhibits some hysteresis with the effect becoming more pronounced with small nanoparticles. This hysteresis most likely results from a higher arsenic affinity for Fe3O4 nanoparticles. This work suggests that Fe3O4 nanocrystals and magnetic separations offer a promising method for arsenic removal.

  5. The flexoelectric effect associated size dependent pyroelectricity in solid dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Gang, E-mail: baigang@njupt.edu.cn [Jiangsu Provincial Engineering Laboratory for RF Integration and Micropackaging and College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China); Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Liu, Zhiguo [Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Xie, Qiyun; Guo, Yanyan; Li, Wei [Jiangsu Provincial Engineering Laboratory for RF Integration and Micropackaging and College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023 (China); Yan, Xiaobing [College of Electronic and information Engineering, Hebei University, Baoding 071002 (China)

    2015-09-15

    A phenomenological thermodynamic theory is used to investigate the effect of strain gradient on the pyroelectric effect in centrosymmetric dielectric solids. Direct pyroelectricity can exist as external mechanical stress is applied to non-pyroelectric dielectrics with shapes such as truncated pyramids, due to elastic strain gradient induced flexoelectric polarization. Effective pyroelectric coefficient was analyzed in truncated pyramids. It is found to be controlled by size, ambient temperature, stress, and aspect ratio and depends mainly on temperature sensitivity of flexoelectric coefficient (TSFC) and strain gradient of the truncated pyramids dielectric solids. These results show that the pyroelectric property of Ba{sub 0.67}Sr{sub 0.33}TiO{sub 3} above T{sub c} similar to PZT and other lead-based ferroelectrics can be obtained. This feature might widely broaden the selection of materials for infrared detectors with preferable properties.

  6. The flexoelectric effect associated size dependent pyroelectricity in solid dielectrics

    Science.gov (United States)

    Bai, Gang; Liu, Zhiguo; Xie, Qiyun; Guo, Yanyan; Li, Wei; Yan, Xiaobing

    2015-09-01

    A phenomenological thermodynamic theory is used to investigate the effect of strain gradient on the pyroelectric effect in centrosymmetric dielectric solids. Direct pyroelectricity can exist as external mechanical stress is applied to non-pyroelectric dielectrics with shapes such as truncated pyramids, due to elastic strain gradient induced flexoelectric polarization. Effective pyroelectric coefficient was analyzed in truncated pyramids. It is found to be controlled by size, ambient temperature, stress, and aspect ratio and depends mainly on temperature sensitivity of flexoelectric coefficient (TSFC) and strain gradient of the truncated pyramids dielectric solids. These results show that the pyroelectric property of Ba0.67Sr0.33TiO3 above Tc similar to PZT and other lead-based ferroelectrics can be obtained. This feature might widely broaden the selection of materials for infrared detectors with preferable properties.

  7. Empirical assessment of published effect sizes and power in the recent cognitive neuroscience and psychology literature.

    Science.gov (United States)

    Szucs, Denes; Ioannidis, John P A

    2017-03-01

    We have empirically assessed the distribution of published effect sizes and estimated power by analyzing 26,841 statistical records from 3,801 cognitive neuroscience and psychology papers published recently. The reported median effect size was D = 0.93 (interquartile range: 0.64-1.46) for nominally statistically significant results and D = 0.24 (0.11-0.42) for nonsignificant results. Median power to detect small, medium, and large effects was 0.12, 0.44, and 0.73, reflecting no improvement through the past half-century. This is so because sample sizes have remained small. Assuming similar true effect sizes in both disciplines, power was lower in cognitive neuroscience than in psychology. Journal impact factors negatively correlated with power. Assuming a realistic range of prior probabilities for null hypotheses, false report probability is likely to exceed 50% for the whole literature. In light of our findings, the recently reported low replication success in psychology is realistic, and worse performance may be expected for cognitive neuroscience.

  8. Why herd size matters - mitigating the effects of livestock crashes.

    Directory of Open Access Journals (Sweden)

    Marius Warg Næss

    Full Text Available Analysing the effect of pastoral risk management strategies provides insights into a system of subsistence that have persevered in marginal areas for hundreds to thousands of years and may shed light into the future of around 200 million households in the face of climate change. This study investigated the efficiency of herd accumulation as a buffer strategy by analysing changes in livestock holdings during an environmental crisis in the Saami reindeer husbandry in Norway. We found a positive relationship between: (1 pre- and post-collapse herd size; and (2 pre-collapse herd size and the number of animals lost during the collapse, indicating that herd accumulation is an effective but costly strategy. Policies that fail to incorporate the risk-beneficial aspect of herd accumulation will have a limited effect and may indeed fail entirely. In the context of climate change, official policies that incorporate pastoral risk management strategies may be the only solution for ensuring their continued existence.

  9. Pleiotropic Effects of DDT Resistance on Male Size and Behaviour.

    Science.gov (United States)

    Rostant, Wayne G; Bowyer, Jemima; Coupland, Jack; Facey, James; Hosken, David J; Wedell, Nina

    2017-07-01

    Understanding the evolution and spread of insecticide resistance requires knowing the relative fitness of resistant organisms. In the absence of insecticides, resistance is predicted to be costly. The Drosophila melanogaster DDT resistance allele (DDT-R) is associated with a male mating cost. This could be because resistant males are generally smaller, but DDT-R may also alter courtship behaviours. Here we tested for body size and courtship effects of DDT-R on mating success in competitive and non-competitive mating trials respectively. We also assessed relative aggression in resistant and susceptible males because aggression can also influence mating success. While the effect of DDT-R on male size partly contributed to reduced mating success, resistant males also had lower rates of courtship and were less aggressive than susceptible males. These differences contribute to the observed DDT-R mating costs. Additionally, these pleiotropic effects of DDT-R are consistent with the history and spread of resistance alleles in nature.

  10. Effect Sizes for Research Univariate and Multivariate Applications

    CERN Document Server

    Grissom, Robert J

    2011-01-01

    Noted for its comprehensive coverage, this greatly expanded new edition now covers the use of univariate and multivariate effect sizes. Many measures and estimators are reviewed along with their application, interpretation, and limitations. Noted for its practical approach, the book features numerous examples using real data for a variety of variables and designs, to help readers apply the material to their own data. Tips on the use of SPSS, SAS, R, and S-Plus are provided. The book's broad disciplinary appeal results from its inclusion of a variety of examples from psychology, medicine, educa

  11. Finite size effects in quark-gluon plasma formation

    International Nuclear Information System (INIS)

    Gopie, Andy; Ogilvie, Michael C.

    1999-01-01

    Using lattice simulations of quenched QCD we estimate the finite size effects present when a gluon plasma equilibrates in a slab geometry, i.e., finite width but large transverse dimensions. Significant differences are observed in the free energy density for the slab when compared with bulk behavior. A small shift in the critical temperature is also seen. The free energy required to liberate heavy quarks relative to bulk is measured using Polyakov loops; the additional free energy required is on the order of 30 - 40 MeV at 2 - 3 T c

  12. Size effect of glulam beams in tension perpendicular to grain

    DEFF Research Database (Denmark)

    Astrup, Thomas; Clorius, Christian Odin; Damkilde, Lars

    2007-01-01

    The strength of wood is reduced when the stressed volume is increased. The phenomenon is termed size effect and is often explained as being stochastic in the sense that the probability of weak locations occurring in the wood increases with increased volume. This paper presents the hypothesis...... that the lower strength is caused by stress concentrations. The stress concentrations arise from the anisotropic structure of wood, and are therefore deterministic. The hypothesis is substantiated through extensive FEM-calculations and experiments. A reasonable agreement between ultimate stresses determined...

  13. The size effects upon shock plastic compression of nanocrystals

    Science.gov (United States)

    Malygin, G. A.; Klyavin, O. V.

    2017-10-01

    For the first time a theoretical analysis of scale effects upon the shock plastic compression of nanocrystals is implemented in the context of a dislocation kinetic approach based on the equations and relationships of dislocation kinetics. The yield point of crystals τy is established as a quantitative function of their cross-section size D and the rate of shock deformation as τy ɛ2/3 D. This dependence is valid in the case of elastic stress relaxation on account of emission of dislocations from single-pole Frank-Read sources near the crystal surface.

  14. Transport, retention, and size perturbation of graphene oxide in saturated porous media: Effects of input concentration and grain size

    Science.gov (United States)

    Accurately predicting the fate and transport of graphene oxide (GO) in porous media is critical to assess its environmental impact. In this work, sand column experiments were conducted to determine the effect of input concentration and grain size on transport, retention, and size perturbation of GO ...

  15. Size Effects on Deformation and Fracture of Scandium Deuteride Films.

    Energy Technology Data Exchange (ETDEWEB)

    Teresi, C. S. [Univ. of Minnesota, Minneapolis, MN (United States); Hintsala, E. [Univ. of Minnesota, Minneapolis, MN (United States); Hysitron, Inc., Eden Prairie, MN (United States); Adams, David P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Yang, Nancy Y. C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kammler, Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moody, N. R. [Univ. of Minnesota, Minneapolis, MN (United States); Gerberich, W. W. [Univ. of Minnesota, Minneapolis, MN (United States)

    2017-07-01

    Metal hydride films have been observed to crack during production and use, prompting mechanical property studies of scandium deuteride films. The following focuses on elastic modulus, fracture, and size effects observed in the system for future film mechanical behavior modeling efforts. Scandium deuteride films were produced through the deuterium charging of electron beam evaporated scandium films using X-ray diffraction, scanning Auger microscopy, and electron backscatter diffraction to monitor changes in the films before and after charging. Scanning electron microscopy, nanoindentation, and focused ion beam machined micropillar compression tests were used for mechanical characterization of the scandium deuteride films. The micropillars showed a size effect for flow stress, indicating that film thickness is a relevant tuning parameter for film performance, and that fracture was controlled by the presence of grain boundaries. Elastic modulus was determined by both micropillar compression and nanoindentation to be approximately 150 GPa, Fracture studies of bulk film channel cracking as well as compression induced cracks in some of the pillars yielded a fracture toughness around 1.0 MPa-m1/2. Preliminary Weibull distributions of fracture in the micropillars are provided. Despite this relatively low value of fracture toughness, scandium deuteride micropillars can undergo a large degree of plasticity in small volumes and can harden to some degree, demonstrating the ductile and brittle nature of this material

  16. fB from finite size effects in lattice QCD

    International Nuclear Information System (INIS)

    Guagnelli, M.; Palombi, F.; Petronzio, R.; Tantalo, N.

    2003-01-01

    We discuss a novel method to calculate f B on the lattice, introduced in [1], based on the study of the dependence of finite size effects upon the heavy quark mass of flavoured mesons and on a non-perturbative recursive finite size technique. This method avoids the systematic errors related to extrapolations from the static limit or to the tuning of the coefficients of effective Lagrangian and the results admit an extrapolation to the continuum limit. We show the results of a first estimate at finite lattice spacing, but close to the continuum limit, giving f B = 170(11)(5)(22) MeV. We also obtain f B s = 192(9)(5)(24)MeV. The first error is statistical, the second is our estimate of the systematic error from the method and the third the systematic error from the specific approximations adopted in this first exploratory calculation. The method can be generalized to two-scale problems in lattice QCD

  17. Accuracy of various impression materials and methods for two implant systems: An effect size study.

    Science.gov (United States)

    Schmidt, Alexander; Häussling, Teresa; Rehmann, Peter; Schaaf, Heidrun; Wöstmann, Bernd

    2018-04-01

    An accurate impression is required for implant treatment. The aim of this in-vitro study was to determine the effect size of the impression material/method, implant system and implant angulation on impression transfer precision. An upper jaw model with three BEGO and three Straumann implants (angulations 0°, 15°, 20°) in the left and right maxilla was used as a reference model. One polyether (Impregum Penta) and two polyvinyl siloxanes (Flexitime Monophase/Aquasil Ultra Monophase) were examined with two impression techniques (open and closed tray). A total of 60 impressions were made. A coordinate measurement machine was used to measure the target variables for 3D-shift, implant axis inclination and implant axis rotation. All the data were subjected to a four-way ANOVA. The effect size (partial eta-squared [η 2 P ]) was reported. The impression material had a significant influence on the 3D shift and the implant axis inclination deviation (p-values=.000), and both factors had very large effect sizes (3D-shift [η 2 P ]=.599; implant axis inclination [η 2 P ]=.298). Impressions made with polyvinyl siloxane exhibited the highest transfer precision. When the angulation of the implants was larger, more deviations occurred for the implant axis rotational deviation. The implant systems and impression methods showed partially significant variations (p-values=.001-.639) but only very small effect sizes (η 2 P =.001-.031). The impression material had the greatest effect size on accuracy in terms of the 3D shift and the implant axis inclination. For multiunit restorations with disparallel implants, polyvinyl siloxane materials should be considered. In addition, the effect size of a multivariate investigation should be reported. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  18. Equipment size effects on open pit mining performance

    Energy Technology Data Exchange (ETDEWEB)

    A. Bozorgebrahimi; R.A. Hall; M.A. Morin [University of British Columbia, Vancouver, BC (Canada). Mining Engineering Department

    2005-03-01

    This paper discusses the exploitation of economies of scale in open pit mining through the use of increasingly larger equipment. It presents a method adopted to evaluate the impact of increased scale on operational performance factors. The work identifies equipment size sensitive variables (ESSVs) in the mine design process that affect the performance of the production process. Data from a set of case studies show that the ESSV influence extends beyond mine production to encompass milling performance, environmental footprint and community impacts. Some ESSVs (such as reliability, tyre costs and productivity) are shown to be related to the current state of equipment technology and their effects are therefore comparable for different mines. Other ESSVs relate to the mine and deposit characteristics; their effects therefore vary from mine to mine. A detailed analytical approach, developed to model the impact of ESSVs, suggests that for truck/shovel operations, the industry may be approaching a situation of diseconomies of scale.

  19. Cost-effective unilateral climate policy design: Size Matters

    Energy Technology Data Exchange (ETDEWEB)

    Boehringer, Christoph; Fischer, Carolyn; Rosendahl, Knut Einar

    2011-07-01

    Given the bleak prospects for a global agreement on mitigating climate change, pressure for unilateral abatement is increasing. A major challenge is emissions leakage. Border carbon adjustments and output-based allocation of emissions allowances can increase effectiveness of unilateral action but introduce distortions of their own. We assess antileakage measures as a function of abatement coalition size. We first develop a partial equilibrium analytical framework to see how these instruments affect emissions within and outside the coalition. We then employ a computable general equilibrium model of international trade and energy use to assess the strategies as the coalition grows. We find that full border adjustments rank first in global cost-effectiveness, followed by import tariffs and output-based rebates. The differences across measures and their overall appeal decline as the abatement coalition grows. In terms of cost, the coalition countries prefer border carbon adjustments; countries outside the coalition prefer output-based rebates.(Author)

  20. Reported shoes size during GH therapy: is foot overgrowth a myth or reality?

    Science.gov (United States)

    Lago, Débora C F; Coutinho, Cláudia A; Kochi, Cristiane; Longui, Carlos A

    2015-10-01

    To describe population reference values for shoes size, and to identify possible disproportional foot growth during GH therapy. Construction of percentile chart based on 3,651 controls (male: 1,838; female: 1,813). The GH treated group included 13 children with idiopathic short stature (ISS) and 50 children with normal height, but with height prediction below their target height; male: 26 and female: 37 mean ± SD age 13.3 ± 1.9 and 12.9 ± 1.5 years, respectively. GH (0.05 mg/kg/day) was used for 3.2 ± 1.6 years, ranging from 1.0-10.3 years. Height expressed as SDS, target height (TH) SDS, self-reported shoes size and target shoes size (TSS) SDS were recorded. Reference values were established showed as a foot SDS calculator available online at www.clinicalcaselearning.com/v2. Definitive shoes size was attained in controls at mean age of 13y in girls and 14y in boys (average values 37 and 40, respectively). In the study group, shoes size was -0.15 ± 0.9 and -0.02 ± 1.3 SDS, with target feet of 0.08 ± 0.8 and -0.27 ± 0.7 SDS in males and females, respectively. There was a significant positive correlation between shoes size and familial TSS, between shoes size and height and between TSS and TH. There was no correlation between duration of GH treatment and shoes size. Our data suggest that during long-term treatment with GH, patients maintain proportional growth in shoes size and height, and the expected correlation with the familial target. We conclude that there is no excessive increase in the size of foot as estimated by the size of shoes in individuals under long term GH therapy.

  1. Effects of Na and Ca on particle size; Effect of filtering on UV absorbance

    Data.gov (United States)

    U.S. Environmental Protection Agency — Effects of Na and Ca on particle size; Effect of filtering on UV absorbance. This dataset is associated with the following publication: Bouchard, D., C. Knightes, X....

  2. Community Size Effects on Epidemic Spreading in Multiplex Social Networks.

    Directory of Open Access Journals (Sweden)

    Ting Liu

    Full Text Available The dynamical process of epidemic spreading has drawn much attention of the complex network community. In the network paradigm, diseases spread from one person to another through the social ties amongst the population. There are a variety of factors that govern the processes of disease spreading on the networks. A common but not negligible factor is people's reaction to the outbreak of epidemics. Such reaction can be related information dissemination or self-protection. In this work, we explore the interactions between disease spreading and population response in terms of information diffusion and individuals' alertness. We model the system by mapping multiplex networks into two-layer networks and incorporating individuals' risk awareness, on the assumption that their response to the disease spreading depends on the size of the community they belong to. By comparing the final incidence of diseases in multiplex networks, we find that there is considerable mitigation of diseases spreading for full phase of spreading speed when individuals' protection responses are introduced. Interestingly, the degree of community overlap between the two layers is found to be critical factor that affects the final incidence. We also analyze the consequences of the epidemic incidence in communities with different sizes and the impacts of community overlap between two layers. Specifically, as the diseases information makes individuals alert and take measures to prevent the diseases, the effective protection is more striking in small community. These phenomena can be explained by the multiplexity of the networked system and the competition between two spreading processes.

  3. Community Size Effects on Epidemic Spreading in Multiplex Social Networks.

    Science.gov (United States)

    Liu, Ting; Li, Ping; Chen, Yan; Zhang, Jie

    2016-01-01

    The dynamical process of epidemic spreading has drawn much attention of the complex network community. In the network paradigm, diseases spread from one person to another through the social ties amongst the population. There are a variety of factors that govern the processes of disease spreading on the networks. A common but not negligible factor is people's reaction to the outbreak of epidemics. Such reaction can be related information dissemination or self-protection. In this work, we explore the interactions between disease spreading and population response in terms of information diffusion and individuals' alertness. We model the system by mapping multiplex networks into two-layer networks and incorporating individuals' risk awareness, on the assumption that their response to the disease spreading depends on the size of the community they belong to. By comparing the final incidence of diseases in multiplex networks, we find that there is considerable mitigation of diseases spreading for full phase of spreading speed when individuals' protection responses are introduced. Interestingly, the degree of community overlap between the two layers is found to be critical factor that affects the final incidence. We also analyze the consequences of the epidemic incidence in communities with different sizes and the impacts of community overlap between two layers. Specifically, as the diseases information makes individuals alert and take measures to prevent the diseases, the effective protection is more striking in small community. These phenomena can be explained by the multiplexity of the networked system and the competition between two spreading processes.

  4. Effect of head size on 10B dose distribution

    International Nuclear Information System (INIS)

    Gupta, N.; Blue, T.E.; Gahbauer, R.

    1992-01-01

    Boron neutron capture therapy (BNCT) for treatment of brain tumors is based on the utilization of large epithermal-neutron fields. Epithermal neutrons thermalize at depths of ∼2.5 cm inside the head and provide a maximum thermal fluence at deep-seated tumor sites with minimum damage to normal tissue. Brain tissue is a highly scattering medium for epithermal and thermal neutrons; therefore, a broad treatment field enables epithermal neutrons to enter the head over a large area. These neutrons slow down as they undergo scattering collisions and contribute to the thermal-neutron fluence at the tumor location. With the use of large neutron fields, the size of the head affects the thermal-neutron distribution and thereby the 10 B absorbed dose distribution inside the head. In this paper, the authors describe measurements using a boron trifluoride (BF 3 )-filled proportional counter to determine the effect of head size on 10 B absorbed dose distributions for a broad field accelerator epithermal-neutron source

  5. Nosewitness Identification: Effects of Lineup Size and Retention Interval.

    Science.gov (United States)

    Alho, Laura; Soares, Sandra C; Costa, Liliana P; Pinto, Elisa; Ferreira, Jacqueline H T; Sorjonen, Kimmo; Silva, Carlos F; Olsson, Mats J

    2016-01-01

    Although canine identification of body odor (BO) has been widely used as forensic evidence, the concept of nosewitness identification by human observers was only recently put to the test. The results indicated that BOs associated with male characters in authentic crime videos could later be identified in BO lineup tests well above chance. To further evaluate nosewitness memory, we assessed the effects of lineup size (Experiment 1) and retention interval (Experiment 2), using a forced-choice memory test. The results showed that nosewitness identification works for all lineup sizes (3, 5, and 8 BOs), but that larger lineups compromise identification performance in similarity to observations from eye- and earwitness studies. Also in line with previous eye- and earwitness studies, but in disagreement with some studies on odor memory, Experiment 2 showed significant forgetting between shorter retention intervals (15 min) and longer retention intervals (1-week) using lineups of five BOs. Altogether this study shows that identification of BO in a forensic setting is possible and has limits and characteristics in line with witness identification through other sensory modalities.

  6. Heating temperature effect on ferritic grain size of rotor steel

    International Nuclear Information System (INIS)

    Cheremnykh, V.G.; Derevyankin, E.V.; Sakulin, A.A.

    1983-01-01

    The heating temperature effect on ferritic grain size of two steels 13Kh1M1FA and 25Kh1M1FA is evaluated. It is shown that exposure time increase at heating temperatures below 1000 deg C up to 10h changes but slightly the size of the Cr-Mo-V ferritic grain of rotor steel cooled with 25 deg C/h rate. Heating up to 1000 deg C and above leads to substantial ferritic grain growth. The kinetics of ferritic grain growth is determined by the behaviour of phases controlling the austenitic grain growth, such as carbonitrides VCsub(0.14)Nsub(0.78) in 13Kh1M1FA steel and VCsub(0.18)Nsub(0.72) in 25Kh1M1FA steel. Reduction of carbon and alloying elements content in steel composition observed at the liquation over rotor length leads to a certain decrease of ferritic grain resistance to super heating

  7. Artificial fish schools : Collective effects of school size, body size, and body form

    NARCIS (Netherlands)

    Kunz, H.; Hemelrijk, C.K.

    2003-01-01

    Individual-based models of schooling in fish have demonstrated that, via processes of self-organization. artificial fish may school in the absence of a leader or external stimuli, using local information only. We study for the first time how body size and body form of artificial fish affect school

  8. Particle size dependent confinement and lattice strain effects in LiFePO4.

    Science.gov (United States)

    Shahid, Raza; Murugavel, Sevi

    2013-11-21

    We report the intrinsic electronic properties of LiFePO4 (LFP) with different particle sizes measured by broad-band impedance spectroscopy and diffuse reflectance spectroscopy. The electronic properties show typical size-dependent effects with decreasing particle size (up to 150 nm). However, at the nanoscale level, we observed an enhancement in the polaronic conductivity about an order of magnitude. We found that the origin of the enhanced electronic conductivity in LFP is due to the significant lattice strain associated with the reduction of particle size. The observed lattice strain component corresponds to the compressive part which leads to a decrease in the hopping length of the polarons. We reproduce nonlinearities in the transport properties of LFP with particle size, to capture the interplay between confinement and lattice strain, and track the effects of strain on the electron-phonon interactions. These results could explain why nano-sized LFP has a better discharge capacity and higher rate capability than the bulk counterpart. We suggest that these new correlations will bring greater insight and better understanding for the optimization of LFP as a cathode material for advanced lithium ion batteries.

  9. Finite-size effect on optimal efficiency of heat engines.

    Science.gov (United States)

    Tajima, Hiroyasu; Hayashi, Masahito

    2017-07-01

    The optimal efficiency of quantum (or classical) heat engines whose heat baths are n-particle systems is given by the strong large deviation. We give the optimal work extraction process as a concrete energy-preserving unitary time evolution among the heat baths and the work storage. We show that our optimal work extraction turns the disordered energy of the heat baths to the ordered energy of the work storage, by evaluating the ratio of the entropy difference to the energy difference in the heat baths and the work storage, respectively. By comparing the statistical mechanical optimal efficiency with the macroscopic thermodynamic bound, we evaluate the accuracy of the macroscopic thermodynamics with finite-size heat baths from the statistical mechanical viewpoint. We also evaluate the quantum coherence effect on the optimal efficiency of the cycle processes without restricting their cycle time by comparing the classical and quantum optimal efficiencies.

  10. Anharmonic, dimensionality and size effects in phonon transport

    Science.gov (United States)

    Thomas, Iorwerth O.; Srivastava, G. P.

    2017-12-01

    We have developed and employed a numerically efficient semi- ab initio theory, based on density-functional and relaxation-time schemes, to examine anharmonic, dimensionality and size effects in phonon transport in three- and two-dimensional solids of different crystal symmetries. Our method uses third- and fourth-order terms in crystal Hamiltonian expressed in terms of a temperature-dependent Grüneisen’s constant. All input to numerical calculations are generated from phonon calculations based on the density-functional perturbation theory. It is found that four-phonon processes make important and measurable contribution to lattice thermal resistivity above the Debye temperature. From our numerical results for bulk Si, bulk Ge, bulk MoS2 and monolayer MoS2 we find that the sample length dependence of phonon conductivity is significantly stronger in low-dimensional solids.

  11. Finite-size effects on current correlation functions

    Science.gov (United States)

    Chen, Shunda; Zhang, Yong; Wang, Jiao; Zhao, Hong

    2014-02-01

    We study why the calculation of current correlation functions (CCFs) still suffers from finite-size effects even when the periodic boundary condition is taken. Two important one-dimensional, momentum-conserving systems are investigated as examples. Intriguingly, it is found that the state of a system recurs in the sense of microcanonical ensemble average, and such recurrence may result in oscillations in CCFs. Meanwhile, we find that the sound mode collisions induce an extra time decay in a current so that its correlation function decays faster (slower) in a smaller (larger) system. Based on these two unveiled mechanisms, a procedure for correctly evaluating the decay rate of a CCF is proposed, with which our analysis suggests that the global energy CCF decays as ˜t-2/3 in the diatomic hard-core gas model and in a manner close to ˜t-1/2 in the Fermi-Pasta-Ulam-β model.

  12. Effect of particle size on the thermoluminescent response of hydroxyapatite

    International Nuclear Information System (INIS)

    Barrera V, A.; Zarate M, J.; Contreras, M. E.; Rivera M, T.

    2016-10-01

    We present the study of the structural characterization and the thermoluminescent response of the hydroxyapatite as a function of the calcination temperature and the effect of the particle size. For precipitation synthesis, calcium nitrate (Ca(NO_3)_2 and dibasic ammonium phosphate ((NH_4)_2HPO_4) were used as precursors and ammonium hydroxide (NH_4OH) as a ph controlling agent. The characterization of the samples was carried out by the techniques of X-ray diffraction, scanning electron microscopy and infrared spectroscopy. The powders obtained are composed of hydroxyapatite, with a different degree of dehydroxylation. The thermoluminescent characterization indicates that at higher calcination temperature there is a higher thermoluminescent response, the calcined powders at 1300 degrees Celsius show a very well defined brightness curve with a higher intensity, with its maximum intensity located at a temperature of 210 degrees Celsius, which indicates that this material can be used as a dosimeter. (Author)

  13. Indentation size effect and the plastic compressibility of glass

    Energy Technology Data Exchange (ETDEWEB)

    Smedskjaer, Morten M., E-mail: mos@bio.aau.dk [Section of Chemistry, Aalborg University, 9000 Aalborg (Denmark)

    2014-06-23

    Oxide glasses exhibit significant densification under an applied isostatic pressure at the glass transition temperature. The glass compressibility is correlated with the chemical composition and atomic packing density, e.g., borate glasses with planar triangular BO{sub 3} units are more disposed for densification than silicate glasses with tetrahedral units. We here show that there is a direct relation between the plastic compressibility following hot isostatic compression and the extent of the indentation size effect (ISE), which is the decrease of hardness with indentation load exhibited by most materials. This could suggest that the ISE is correlated with indentation-induced shear bands, which should form in greater density when the glass network is more adaptable to volume changes through structural and topological rearrangements under an applied pressure.

  14. Word length, set size, and lexical factors: Re-examining what causes the word length effect.

    Science.gov (United States)

    Guitard, Dominic; Gabel, Andrew J; Saint-Aubin, Jean; Surprenant, Aimée M; Neath, Ian

    2018-04-19

    The word length effect, better recall of lists of short (fewer syllables) than long (more syllables) words has been termed a benchmark effect of working memory. Despite this, experiments on the word length effect can yield quite different results depending on set size and stimulus properties. Seven experiments are reported that address these 2 issues. Experiment 1 replicated the finding of a preserved word length effect under concurrent articulation for large stimulus sets, which contrasts with the abolition of the word length effect by concurrent articulation for small stimulus sets. Experiment 2, however, demonstrated that when the short and long words are equated on more dimensions, concurrent articulation abolishes the word length effect for large stimulus sets. Experiment 3 shows a standard word length effect when output time is equated, but Experiments 4-6 show no word length effect when short and long words are equated on increasingly more dimensions that previous demonstrations have overlooked. Finally, Experiment 7 compared recall of a small and large neighborhood words that were equated on all the dimensions used in Experiment 6 (except for those directly related to neighborhood size) and a neighborhood size effect was still observed. We conclude that lexical factors, rather than word length per se, are better predictors of when the word length effect will occur. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  15. Aerodynamic Ground Effect in Fruitfly Sized Insect Takeoff.

    Directory of Open Access Journals (Sweden)

    Dmitry Kolomenskiy

    Full Text Available Aerodynamic ground effect in flapping-wing insect flight is of importance to comparative morphologies and of interest to the micro-air-vehicle (MAV community. Recent studies, however, show apparently contradictory results of either some significant extra lift or power savings, or zero ground effect. Here we present a numerical study of fruitfly sized insect takeoff with a specific focus on the significance of leg thrust and wing kinematics. Flapping-wing takeoff is studied using numerical modelling and high performance computing. The aerodynamic forces are calculated using a three-dimensional Navier-Stokes solver based on a pseudo-spectral method with volume penalization. It is coupled with a flight dynamics solver that accounts for the body weight, inertia and the leg thrust, while only having two degrees of freedom: the vertical and the longitudinal horizontal displacement. The natural voluntary takeoff of a fruitfly is considered as reference. The parameters of the model are then varied to explore possible effects of interaction between the flapping-wing model and the ground plane. These modified takeoffs include cases with decreased leg thrust parameter, and/or with periodic wing kinematics, constant body pitch angle. The results show that the ground effect during natural voluntary takeoff is negligible. In the modified takeoffs, when the rate of climb is slow, the difference in the aerodynamic forces due to the interaction with the ground is up to 6%. Surprisingly, depending on the kinematics, the difference is either positive or negative, in contrast to the intuition based on the helicopter theory, which suggests positive excess lift. This effect is attributed to unsteady wing-wake interactions. A similar effect is found during hovering.

  16. X-ray tube focal spot sizes: comprehensive studies of their measurement and effect of measured size in angiography

    International Nuclear Information System (INIS)

    Doi, K.; Loo, L.N.; Chan, H.P.

    1982-01-01

    Thirty-two focal spot sizes of four x-ray tubes were measured by the pinhole, star pattern, slit, and root-mean-square (RMS) methods under various exposure conditions. The modulation transfer functions (MTFs) and line spread functions (LSFs) were also determined. The star pattern focal spot sizes agreed with the effective sizes calculated from the frequencies at the first minimum of the MTF within 0.04 mm for large focal spots and within 0.01 mm for small focal spots. The focal spot size determined by the slit method was approximately equal to the width of the LSF at the cutoff level of 0.15 +/- 0.06 of the peak value. The RMS method provided the best correlation between the measured focal spot sizes and the corresponding image distributions of blood vessels. The pinhole and slit methods tended to overestimate the focal spot size, but the star pattern method tended to underestimate it. For approximately 90% of the focal spots, the average of the star and slit (or pinhole) focal spot sizes agreed with the RMS focal spot size within +/- 0.1 mm

  17. Effect of sample size on bias correction performance

    Science.gov (United States)

    Reiter, Philipp; Gutjahr, Oliver; Schefczyk, Lukas; Heinemann, Günther; Casper, Markus C.

    2014-05-01

    The output of climate models often shows a bias when compared to observed data, so that a preprocessing is necessary before using it as climate forcing in impact modeling (e.g. hydrology, species distribution). A common bias correction method is the quantile matching approach, which adapts the cumulative distribution function of the model output to the one of the observed data by means of a transfer function. Especially for precipitation we expect the bias correction performance to strongly depend on sample size, i.e. the length of the period used for calibration of the transfer function. We carry out experiments using the precipitation output of ten regional climate model (RCM) hindcast runs from the EU-ENSEMBLES project and the E-OBS observational dataset for the period 1961 to 2000. The 40 years are split into a 30 year calibration period and a 10 year validation period. In the first step, for each RCM transfer functions are set up cell-by-cell, using the complete 30 year calibration period. The derived transfer functions are applied to the validation period of the respective RCM precipitation output and the mean absolute errors in reference to the observational dataset are calculated. These values are treated as "best fit" for the respective RCM. In the next step, this procedure is redone using subperiods out of the 30 year calibration period. The lengths of these subperiods are reduced from 29 years down to a minimum of 1 year, only considering subperiods of consecutive years. This leads to an increasing number of repetitions for smaller sample sizes (e.g. 2 for a length of 29 years). In the last step, the mean absolute errors are statistically tested against the "best fit" of the respective RCM to compare the performances. In order to analyze if the intensity of the effect of sample size depends on the chosen correction method, four variations of the quantile matching approach (PTF, QUANT/eQM, gQM, GQM) are applied in this study. The experiments are further

  18. Effect Size Analyses of Souvenaid in Patients with Alzheimer?s Disease

    OpenAIRE

    Cummings, Jeffrey; Scheltens, Philip; McKeith, Ian; Blesa, Rafael; Harrison, John E.; Bertolucci, Paulo H.F.; Rockwood, Kenneth; Wilkinson, David; Wijker, Wouter; Bennett, David A.; Shah, Raj C.

    2016-01-01

    Background: Souvenaid? (uridine monophosphate, docosahexaenoic acid, eicosapentaenoic acid, choline, phospholipids, folic acid, vitamins B12, B6, C, and E, and selenium), was developed to support the formation and function of neuronal membranes. Objective: To determine effect sizes observed in clinical trials of Souvenaid and to calculate the number needed to treat to show benefit or harm. Methods: Data from all three reported randomized controlled trials of Souvenaid in Alzheimer?s disease (...

  19. Effects of Social Support Network Size on Mortality Risk: Considerations by Diabetes Status.

    Science.gov (United States)

    Loprinzi, Paul D; Ford, M Allison

    2018-05-01

    Previous work demonstrates that social support is inversely associated with mortality risk. Less research, however, has examined the effects of the size of the social support network on mortality risk among those with and without diabetes, which was the purpose of this study. Data from the 1999-2008 National Health and Nutrition Examination Survey were used, with participants followed through 2011. This study included 1,412 older adults (≥60 years of age) with diabetes and 5,872 older adults without diabetes. The size of the social support network was assessed via self-report and reported as the number of participants' close friends. Among those without diabetes, various levels of social support network size were inversely associated with mortality risk. However, among those with diabetes, only those with a high social support network size (i.e., at least six close friends) had a reduced risk of all-cause mortality. That is, compared to those with zero close friends, those with diabetes who had six or more close friends had a 49% reduced risk of all-cause mortality (hazard ratio 0.51, 95% CI 0.27-0.94). To mitigate mortality risk, a greater social support network size may be needed for those with diabetes.

  20. The use of the effect size in JCR Spanish journals of psychology: from theory to fact.

    Science.gov (United States)

    García García, Juan; Ortega Campos, Elena; De la Fuente Sánchez, Leticia

    2011-11-01

    In 1999, Wilkinson and the Task Force on Statistical Inference published "Statistical Methods and Psychology: Guidelines and Explanation." The authors made several recommendations about how to improve the quality of Psychology research papers. One of these was to report some effect-size index in the results of the research. In 2001, the fifth edition of the Publication Manual of the American Psychological Association included this recommendation. In Spain, in 2003, scientific journals like Psicothema or the International Journal of Clinical and Health Psychology (IJCHP) published editorials and papers expressing the need to calculate the effect size in the research papers. The aim of this study is to determine whether the papers published from 2003 to 2008 in the four Spanish journals indexed in the Journal Citation Reports have reported some effect-size index of their results. The findings indicate that, in general, the followup of the norm has been scanty, though the evolution over the analyzed period is different depending on the journal.

  1. Underestimated effect sizes in GWAS: fundamental limitations of single SNP analysis for dichotomous phenotypes.

    Directory of Open Access Journals (Sweden)

    Sven Stringer

    Full Text Available Complex diseases are often highly heritable. However, for many complex traits only a small proportion of the heritability can be explained by observed genetic variants in traditional genome-wide association (GWA studies. Moreover, for some of those traits few significant SNPs have been identified. Single SNP association methods test for association at a single SNP, ignoring the effect of other SNPs. We show using a simple multi-locus odds model of complex disease that moderate to large effect sizes of causal variants may be estimated as relatively small effect sizes in single SNP association testing. This underestimation effect is most severe for diseases influenced by numerous risk variants. We relate the underestimation effect to the concept of non-collapsibility found in the statistics literature. As described, continuous phenotypes generated with linear genetic models are not affected by this underestimation effect. Since many GWA studies apply single SNP analysis to dichotomous phenotypes, previously reported results potentially underestimate true effect sizes, thereby impeding identification of true effect SNPs. Therefore, when a multi-locus model of disease risk is assumed, a multi SNP analysis may be more appropriate.

  2. Effects of Meaning and Symmetry on Judgments of Size

    DEFF Research Database (Denmark)

    Reber, Rolf; Christensen, Bo T.; Meier, Beat

    2014-01-01

    to be judged as larger than asymmetric numbers (e.g., 43). However, recent research found that symmetric numbers were judged to be smaller than asymmetric numbers. This finding suggests that the mechanisms underlying size judgments may differ in meaningful and meaningless materials. Supporting this notion, we...... showed in Experiment 1 that meaning increased judged size, whereas symmetry decreased judged size. In the next two experiments, we excluded several alternative explanations for the differences in size judgments between meaningful and meaningless materials in earlier studies. This finding contradicts...

  3. Size effects on negative thermal expansion in cubic ScF{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.; Guo, X. G.; Zhang, K. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Tong, P., E-mail: tongpeng@issp.ac.cn; Lin, J. C.; Wang, M.; Wu, Y.; Lin, S.; Xu, W.; Song, W. H. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Huang, P. C. [University of Science and Technology of China, Hefei 230026 (China); High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031 (China); Sun, Y. P., E-mail: ypsun@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2016-07-11

    Scandium trifluoride (ScF{sub 3}), adopting a cubic ReO{sub 3}-type structure at ambient pressure, undergoes a pronounced negative thermal expansion (NTE) over a wide range of temperatures (10 K–1100 K). Here, we report the size effects on the NTE properties of ScF{sub 3}. The magnitude of NTE is reduced with diminishing the crystal size. As revealed by the specific heat measurement, the low-energy phonon vibrations which account for the NTE behavior are stiffened as the crystal size decreases. With decreasing the crystal size, the peaks in high-energy X-ray pair distribution function (PDF) become broad, which cannot be illuminated by local symmetry breaking. Instead, the broadened PDF peaks are strongly indicative of enhanced atomic displacements which are suggested to be responsible for the stiffening of NTE-related lattice vibrations. The present study suggests that the NTE properties of ReO{sub 3}-type and other open-framework materials can be effectively adjusted by controlling the crystal size.

  4. On size-effects in single crystal wedge indentation

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.

    2012-01-01

    constitutive length parameters to model sizeeffects. The problem is studied numerically using a strain gradient crystal visco-plasticity theory formulated along the lines proposed by Fleck andWillis (2009). It is shown how the force-indentation relation is affected due to size-dependence in the material. Size...

  5. Practical implementation of Channelized Hotelling Observers: Effect of ROI size.

    Science.gov (United States)

    Ferrero, Andrea; Favazza, Christopher P; Yu, Lifeng; Leng, Shuai; McCollough, Cynthia H

    2017-03-01

    Fundamental to the development and application of channelized Hotelling observer (CHO) models is the selection of the region of interest (ROI) to evaluate. For assessment of medical imaging systems, reducing the ROI size can be advantageous. Smaller ROIs enable a greater concentration of interrogable objects in a single phantom image, thereby providing more information from a set of images and reducing the overall image acquisition burden. Additionally, smaller ROIs may promote better assessment of clinical patient images as different patient anatomies present different ROI constraints. To this end, we investigated the minimum ROI size that does not compromise the performance of the CHO model. In this study, we evaluated both simulated images and phantom CT images to identify the minimum ROI size that resulted in an accurate figure of merit (FOM) of the CHO's performance. More specifically, the minimum ROI size was evaluated as a function of the following: number of channels, spatial frequency and number of rotations of the Gabor filters, size and contrast of the object, and magnitude of the image noise. Results demonstrate that a minimum ROI size exists below which the CHO's performance is grossly inaccurate. The minimum ROI size is shown to increase with number of channels and be dictated by truncation of lower frequency filters. We developed a model to estimate the minimum ROI size as a parameterized function of the number of orientations and spatial frequencies of the Gabor filters, providing a guide for investigators to appropriately select parameters for model observer studies.

  6. The effect of group size on vigilance in Ruddy Turnstones

    NARCIS (Netherlands)

    Fuller, R.A.; Bearhop, S.; Metcalfe, N.B.; Piersma, T.

    2013-01-01

    Foraging birds can manage time spent vigilant for predators by forming groups of various sizes. However, group size alone will not always reliably determine the optimal level of vigilance. For example, variation in predation risk or food quality between patches may also be influential. In a field

  7. Eliminating high-order scattering effects in optical microbubble sizing.

    Science.gov (United States)

    Qiu, Huihe

    2003-04-01

    Measurements of bubble size and velocity in multiphase flows are important in much research and many industrial applications. It has been found that high-order refractions have great impact on microbubble sizing by use of phase-Doppler anemometry (PDA). The problem has been investigated, and a model of phase-size correlation, which also takes high-order refractions into consideration, is introduced to improve the accuracy of bubble sizing. Hence the model relaxes the assumption of a single-scattering mechanism in a conventional PDA system. The results of simulation based on this new model are compared with those based on a single-scattering-mechanism approach or a first-order approach. An optimization method for accurately sizing air bubbles in water has been suggested.

  8. Latent hardening size effect in small-scale plasticity

    Science.gov (United States)

    Bardella, Lorenzo; Segurado, Javier; Panteghini, Andrea; Llorca, Javier

    2013-07-01

    We aim at understanding the multislip behaviour of metals subject to irreversible deformations at small-scales. By focusing on the simple shear of a constrained single-crystal strip, we show that discrete Dislocation Dynamics (DD) simulations predict a strong latent hardening size effect, with smaller being stronger in the range [1.5 µm, 6 µm] for the strip height. We attempt to represent the DD pseudo-experimental results by developing a flow theory of Strain Gradient Crystal Plasticity (SGCP), involving both energetic and dissipative higher-order terms and, as a main novelty, a strain gradient extension of the conventional latent hardening. In order to discuss the capability of the SGCP theory proposed, we implement it into a Finite Element (FE) code and set its material parameters on the basis of the DD results. The SGCP FE code is specifically developed for the boundary value problem under study so that we can implement a fully implicit (Backward Euler) consistent algorithm. Special emphasis is placed on the discussion of the role of the material length scales involved in the SGCP model, from both the mechanical and numerical points of view.

  9. Latent hardening size effect in small-scale plasticity

    International Nuclear Information System (INIS)

    Bardella, Lorenzo; Panteghini, Andrea; Segurado, Javier; Llorca, Javier

    2013-01-01

    We aim at understanding the multislip behaviour of metals subject to irreversible deformations at small-scales. By focusing on the simple shear of a constrained single-crystal strip, we show that discrete Dislocation Dynamics (DD) simulations predict a strong latent hardening size effect, with smaller being stronger in the range [1.5 µm, 6 µm] for the strip height. We attempt to represent the DD pseudo-experimental results by developing a flow theory of Strain Gradient Crystal Plasticity (SGCP), involving both energetic and dissipative higher-order terms and, as a main novelty, a strain gradient extension of the conventional latent hardening. In order to discuss the capability of the SGCP theory proposed, we implement it into a Finite Element (FE) code and set its material parameters on the basis of the DD results. The SGCP FE code is specifically developed for the boundary value problem under study so that we can implement a fully implicit (Backward Euler) consistent algorithm. Special emphasis is placed on the discussion of the role of the material length scales involved in the SGCP model, from both the mechanical and numerical points of view. (paper)

  10. Droplet size effects on film drainage between droplet and substrate.

    Science.gov (United States)

    Steinhaus, Benjamin; Spicer, Patrick T; Shen, Amy Q

    2006-06-06

    When a droplet approaches a solid surface, the thin liquid film between the droplet and the surface drains until an instability forms and then ruptures. In this study, we utilize microfluidics to investigate the effects of film thickness on the time to film rupture for water droplets in a flowing continuous phase of silicone oil deposited on solid poly(dimethylsiloxane) (PDMS) surfaces. The water droplets ranged in size from millimeters to micrometers, resulting in estimated values of the film thickness at rupture ranging from 600 nm down to 6 nm. The Stefan-Reynolds equation is used to model film drainage beneath both millimeter- and micrometer-scale droplets. For millimeter-scale droplets, the experimental and analytical film rupture times agree well, whereas large differences are observed for micrometer-scale droplets. We speculate that the differences in the micrometer-scale data result from the increases in the local thin film viscosity due to confinement-induced molecular structure changes in the silicone oil. A modified Stefan-Reynolds equation is used to account for the increased thin film viscosity of the micrometer-scale droplet drainage case.

  11. THE EFFECT OF SEDIMENT GRAIN SIZE ON HEAVY METAL CONTENT

    Directory of Open Access Journals (Sweden)

    Svetlana Maslennikova

    2012-06-01

    Full Text Available In the natural surroundings tectonical, climatological, dynamic and physico-chemical conditions of sedimentation are the crucial factors in the process of sediment composition formation. Grain size is one of the most investigated reasons of space and temporary variability in heavy metal concentration. In general, the data on grain size measurement afford to appreciate sorption capacity of sediments and arrange them. The dependence heavy metal content on grain size of sediments has been examined in the enormous amount of research works. The main conclusion is that if grain size decreases, metal content increases.We have carried out sediment grain size measurement of two lakes (Chebachje Lake, Piketnoye Lake located in the South of Western Siberia, Russia. To define grain size of these sediments the sorting of samples collected layer-by-layer has been conducted by nest of sieves (from 43 to 1000 µm. Accomplished examinations allow to state that layer-by-layer grain size measurement of sediments has significant importance in reconstruction of paleoecologic peculiarities and also influences organic and inorganic matter concentrating in the sediments in dynamics

  12. Ultraviolet (UV) disinfection of grey water: particle size effects.

    Science.gov (United States)

    Winward, G P; Avery, L M; Stephenson, T; Jefferson, B

    2008-02-01

    The impact of water quality on the ultraviolet (UV) disinfection of grey water was investigated with reference to urban water reuse. Direct UV disinfection of grey water did not meet the stringent California State Title 22 criteria for unrestricted urban water reuse due to the presence of particulate material ranging from or = 2000 microm in size. Grey water was manipulated by settling to produce fractions of varying particle size distributions and blending was employed post-disinfection to extract particle-associated coliforms (PACs). The efficacy of UV disinfection was found to be linked to the particle size of the grey water fractions. The larger particle size fractions with a mean particle size of 262 microm and above were observed to shield more coliforms from UV light than did the smaller particles with a mean particle size below 119 microm. Up to 70% of total coliforms in the larger particle size fractions were particle-associated following a UV dose (fluence) of 260 mJ.cm(-2) and would remain undetected by standard coliform enumeration techniques. Implications for urban water reuse are discussed and recommendations made for grey water treatment to ensure removal of particle-associated indicator bacteria and pathogens prior to UV disinfection.

  13. Effect Size Measures for Mediation Models: Quantitative Strategies for Communicating Indirect Effects

    Science.gov (United States)

    Preacher, Kristopher J.; Kelley, Ken

    2011-01-01

    The statistical analysis of mediation effects has become an indispensable tool for helping scientists investigate processes thought to be causal. Yet, in spite of many recent advances in the estimation and testing of mediation effects, little attention has been given to methods for communicating effect size and the practical importance of those…

  14. Progress report on irradiation experiment on small size specimens in high temperature flux module

    Energy Technology Data Exchange (ETDEWEB)

    Ramesh, M.; Jacquet, P.; Chaouadi, R.

    2011-02-15

    This report describes the progress made in IFREC/DEMO Research and Development Program during the year 2010 at SCK/CEN. This task is part of demonstrating the possibility to irradiate small specimens in the HFTM modules that will be used in DEMO. Different small specimens of three candidate materials of DEMO fusion reactor will be irradiated with the objective of validating the specimen geometry and size to reliably characterize the mechanical properties of unirradiated and in future of irradiated materials.

  15. Effects of primary and secondary morphological family size in monolingual and bilingual word processing

    NARCIS (Netherlands)

    Mulder, K.; Dijkstra, A.F.J.; Schreuder, R.; Baayen, Harald

    2014-01-01

    This study investigated primary and secondary morphological family size effects in monolingual and bilingual processing, combining experimentation with computational modeling. Family size effects were investigated in an English lexical decision task for Dutch-English bilinguals and English

  16. Effect of size heterogeneity on community identification in complex networks

    Energy Technology Data Exchange (ETDEWEB)

    Danon, L.; Diaz-Guilera, A.; Arenas, A.

    2008-01-01

    Identifying community structure can be a potent tool in the analysis and understanding of the structure of complex networks. Up to now, methods for evaluating the performance of identification algorithms use ad-hoc networks with communities of equal size. We show that inhomogeneities in community sizes can and do affect the performance of algorithms considerably, and propose an alternative method which takes these factors into account. Furthermore, we propose a simple modification of the algorithm proposed by Newman for community detection (Phys. Rev. E 69 066133) which treats communities of different sizes on an equal footing, and show that it outperforms the original algorithm while retaining its speed.

  17. Finite size effects in lattice QCD with dynamical Wilson fermions

    Energy Technology Data Exchange (ETDEWEB)

    Orth, B.

    2004-06-01

    Due to limited computing resources choosing the parameters for a full lattice QCD simulation always amounts to a compromise between the competing objectives of a lattice spacing as small, quarks as light, and a volume as large as possible. Aiming at pushing unquenched simulations with the standard Wilson action towards the computationally expensive regime of small quark masses, the GRAL project addresses the question whether computing time can be saved by sticking to lattices with rather modest numbers of grid sites and extrapolating the finite-volume results to the infinite volume (prior to the usual chiral and continuum extrapolations). In this context we investigate in this work finite-size effects in simulated light hadron masses. Understanding their systematic volume dependence may not only help saving computer time in light quark simulations with the Wilson action, but also guide future simulations with dynamical chiral fermions which for a foreseeable time will be restricted to rather small lattices. We analyze data from hybrid Monte Carlo simulations with the N{sub f} = 2 Wilson action at two values of the coupling parameter, {beta} = 5.6 (lattice spacing {alpha} {approx} 0.08 fm) and {beta} = 5.32144 ({alpha} {approx} 0.13 fm). The larger {beta} corresponds to the coupling used previously by SESAM/T{chi}L. The considered hopping parameters {kappa} = 0.1575, 0.158 (at the larger {beta}) and {kappa} = 0.1665 (at the smaller {beta}) correspond to quark masses of 85, 50 and 36% of the strange quark mass, respectively. At each quark mass we study at least three different lattice extents in the range from L = 10 to L = 24 (0.85-2.04 fm). Estimates of autocorrelation times in the stochastic updating process and of the computational cost of every run are given. For each simulated sea quark mass we calculate quark propagators and hadronic correlation functions in order to extract the pion, rho and nucleon masses as well as the pion decay constant and the quark mass

  18. Effective population size and evolutionary dynamics in outbred ...

    Indian Academy of Sciences (India)

    populations of fruit flies is not primarily driven by new mutations, but rather by changes in the frequency of ..... Drift simulation: The sex ratio, total population size and ...... Gillespie J. H. 1994a Substitution processes in molecular evolution. II.

  19. Electric field engineering using quantum-size-effect-tuned heterojunctions

    KAUST Repository

    Adinolfi, V.; Ning, Z.; Xu, J.; Masala, Silvia; Zhitomirsky, D.; Thon, S. M.; Sargent, E. H.

    2013-01-01

    be tuned across the light-absorbing semiconductor layer via control over CQD size, employing solution-processed, room-temperature fabricated materials. We exploit this feature by designing and demonstrating a field-enhanced heterojunction architecture. We

  20. The effect of meal size on gastric evacuation in whiting

    DEFF Research Database (Denmark)

    Andersen, Niels Gerner

    1998-01-01

    Gastric evacuation experiments were performed on whiting Merlangius merlangus fed discrete meals of different sizes. Herring Clupea harengus, sandeel Ammodytes tobianus, common goby Pomatoschistus microps, and brown shrimp Crangon crangon were tested as prey. A simple power model to describe...

  1. The Effects of Rain Garden Size on Hydrological Performance

    Science.gov (United States)

    Bioretention systems are vegetated depressions designed to accept stormwater runoff from impervious surfaces. Manuals and guidance documents recommend sizing bioretention cells anywhere from 3% to 43% of their associated drainage areas, based on factors including soil type, slop...

  2. Switching-on quantum size effects in silicon nanocrystals.

    Science.gov (United States)

    Sun, Wei; Qian, Chenxi; Wang, Liwei; Wei, Muan; Mastronardi, Melanie L; Casillas, Gilberto; Breu, Josef; Ozin, Geoffrey A

    2015-01-27

    The size-dependence of the absolute luminescence quantum yield of size-separated silicon nanocrystals reveals a "volcano" behavior, which switches on around 5 nm, peaks at near 3.7-3.9 nm, and decreases thereafter. These three regions respectively define: i) the transition from bulk to strongly quantum confined emissive silicon, ii) increasing confinement enhancing radiative recombination, and iii) increasing contributions favoring non-radiative recombination. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Size and liquidity effects in Nigeria: an industrial sector study

    OpenAIRE

    Hearn, Bruce

    2013-01-01

    This study estimates liquidity premiums using the recently developed Liu (2006) measure within a multifactor capital asset pricing model (CAPM) including size premiums and a time varying parameter model for the West African emerging market of Nigeria. The evidence suggests that liquidity factors are relevant only for financial and basic materials sector stocks while size factor is more generally relevant in explaining the cross section of stock returns in the Nigerian domestic equity market....

  4. Measuring the effectiveness of marketing activities use in relation to company size

    Directory of Open Access Journals (Sweden)

    Lucie Sychrová

    2013-01-01

    Full Text Available The aim of this paper is to research the relationship between measurements of effectiveness of marketing activities and company size. An analysis of the economic sources, professional publications, analysis and reports of previous research shows that the concept of measuring of effectiveness is one of the key themes, which economists always pay much attention. It is a criterion that helps to rationally decide on the use limited resources to meet the needs that are not limited. This topic deals with numerous domestic and foreign literatures. The authors are not only different concepts of effectiveness, but also the using terminology. There are multiple definitions of terms “effectiveness” For the same purpose and meaning. The same concept is often defined semantically different. Therefore, every company has a strong interest to be in all their activities more effectively than the competition. Logical response to changes and requirements of nowadays is using a combination of lot of methods to measure marketing effectiveness. Methods used for this article includes two phases. The first it was gained date by primary research, using a structure questionnaire and processed by statistical software SPSS. Research sample consists 115 companies operating in the Czech environment, which was chosen at random. There is investigated the correlation between measuring the effectiveness of marketing activities and company size. The second part investigated the dependence between the choice of metrics used to measure the effectiveness and company size. The results of the research showed that there is no correlation between measuring the effectiveness of marketing activities and company size. The value of Pearson Chi-Square test is greater than 0.05, it is 0.187. We can presume that dependency does not exist or it is small for these. Value of Symmetric measures is 0.432, which means that the intensity tends to be small rather than high.

  5. Using e-mail recruitment and an online questionnaire to establish effect size: A worked example.

    Science.gov (United States)

    Kirkby, Helen M; Wilson, Sue; Calvert, Melanie; Draper, Heather

    2011-06-09

    Sample size calculations require effect size estimations. Sometimes, effect size estimations and standard deviation may not be readily available, particularly if efficacy is unknown because the intervention is new or developing, or the trial targets a new population. In such cases, one way to estimate the effect size is to gather expert opinion. This paper reports the use of a simple strategy to gather expert opinion to estimate a suitable effect size to use in a sample size calculation. Researchers involved in the design and analysis of clinical trials were identified at the University of Birmingham and via the MRC Hubs for Trials Methodology Research. An email invited them to participate.An online questionnaire was developed using the free online tool 'Survey Monkey©'. The questionnaire described an intervention, an electronic participant information sheet (e-PIS), which may increase recruitment rates to a trial. Respondents were asked how much they would need to see recruitment rates increased by, based on 90%. 70%, 50% and 30% baseline rates, (in a hypothetical study) before they would consider using an e-PIS in their research.Analyses comprised simple descriptive statistics. The invitation to participate was sent to 122 people; 7 responded to say they were not involved in trial design and could not complete the questionnaire, 64 attempted it, 26 failed to complete it. Thirty-eight people completed the questionnaire and were included in the analysis (response rate 33%; 38/115). Of those who completed the questionnaire 44.7% (17/38) were at the academic grade of research fellow 26.3% (10/38) senior research fellow, and 28.9% (11/38) professor. Dependent upon the baseline recruitment rates presented in the questionnaire, participants wanted recruitment rate to increase from 6.9% to 28.9% before they would consider using the intervention. This paper has shown that in situations where effect size estimations cannot be collected from previous research, opinions

  6. Influence of size effects on the radiation stability of nanocrystalline materials

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimenko, N. N.; Smirnov, D. I., E-mail: rmta@miee.ru [National Research University of Electronic Technology “MIET” (Russian Federation); Medetov, N. A. [Kostanai Social and Technical University (Kazakhstan); Zaporozhan, O. A. [National Research University of Electronic Technology “MIET” (Russian Federation)

    2014-12-15

    The data reported in publications are analyzed, and on this basis, problems arising in studies of the radiation stability of nanostructures and nanomaterials are formulated. A phenomenological model of the radiation stability of such objects is considered. The model is based on the concept of the behavior of close Frenkel pairs. To test the model proposed in the study, the effect of the size factor on the degree of structural degradation in nanoporous silicon samples when irradiated with phosphorus ions is studied. The effect of elastic strains on the radiation stability of the structures is established.

  7. Anisotropic failure and size effects in periodic honeycomb materials: A gradient-elasticity approach

    Science.gov (United States)

    Réthoré, Julien; Dang, Thi Bach Tuyet; Kaltenbrunner, Christine

    2017-02-01

    This paper proposes a fracture mechanics model for the analysis of crack propagation in periodic honeycomb materials. The model is based on gradient-elasticity which enables us to account for the effect of the material structure at the macroscopic scale. For simulating the propagation of cracks along an arbitrary path, the numerical implementation is elaborated based on an extended finite element method with the required level of continuity. The two main features captured by the model are directionality and size effect. The numerical predictions are consistent with experimental results on honeycomb materials but also with results reported in the literature for microstructurally short cracks in metals.

  8. Crystallite size effects in stacking faulted nickel hydroxide and its electrochemical behaviour

    International Nuclear Information System (INIS)

    Ramesh, T.N.

    2009-01-01

    β-Nickel hydroxide comprises a long range periodic arrangement of atoms with a stacking sequence of AC AC AC-having an ideal composition Ni(OH) 2 . Variation in the preparative conditions can lead to the changes in the stacking sequence (AC AC BA CB AC AC or AC AC AB AC AC). This type of variation in stacking sequence can result in the formation of stacking fault in nickel hydroxide. The stability of the stacking fault depends on the free energy content of the sample. Stacking faults in nickel hydroxide is essential for better electrochemical activity. Also there are reports correlating particle size to the better electrochemical activity. Here we present the effect of crystallite size on the stacking faulted nickel hydroxide samples. The electrochemical performance of stacking faulted nickel hydroxide with small crystallite size exchanges 0.8e/Ni, while the samples with larger crystallite size exchange 0.4e/Ni. Hence a right combination of crystallite size and stacking fault content has to be controlled for good electrochemical activity of nickel hydroxide

  9. Effect of Crushed Glass Cullet Sizes on Physical and Mechanical Properties of Red Clay Bricks

    Directory of Open Access Journals (Sweden)

    Patricia Ponce Peña

    2016-01-01

    Full Text Available This study reports the effect of clear waste glass from bottles added on 20 to 30 wt.% and variable particle size (<500, <300, and <212 μm, into clay mixtures for the handmade brick manufacturing process. The bricks were manufactured with mixtures of clay, crushed glass, and water in different proportions, homogenized, casted in wooden molds, air-dried at room temperature for 72 h, and sintered at 1000°C for 12 h. Total shrinkage, water absorption, compressive strength, microstructure, and phase composition are discussed with respect to glass content and its particle size. The results indicate that increasing the content of glass and decreasing its particle size enhanced significantly the brick properties of water absorption and compressive strength by up to 18.5% and 6.8 MPa, for bricks with 30 wt% and particle size lower than 212 μm. It is proposed that decreasing the glass particle size its surface area increases allowing easier melting of glass by lower energy consumption, reducing porosity and enhancing brick properties.

  10. Family Configuration and Achievement: Effects of Birth Order and Family Size in a Sample of Brothers.

    Science.gov (United States)

    Olneck, Michael R.; Bills, David B.

    1979-01-01

    Birth order effects in brothers were found to derive from difference in family size. Effects for family size were found even with socioeconomic background controlled. Nor were family size effects explained by parental ability. The importance of unmeasured preferences or economic resources that vary across families was suggested. (Author/RD)

  11. The effect of lexical factors on recall from working memory: Generalizing the neighborhood size effect.

    Science.gov (United States)

    Derraugh, Lesley S; Neath, Ian; Surprenant, Aimée M; Beaudry, Olivia; Saint-Aubin, Jean

    2017-03-01

    The word-length effect, the finding that lists of short words are better recalled than lists of long words, is 1 of the 4 benchmark phenomena that guided development of the phonological loop component of working memory. However, previous work has noted a confound in word-length studies: The short words used had more orthographic neighbors (valid words that can be made by changing a single letter in the target word) than long words. The confound is that words with more neighbors are better recalled than otherwise comparable words with fewer neighbors. Two experiments are reported that address criticisms of the neighborhood-size account of the word-length effect by (1) testing 2 new stimulus sets, (2) using open rather than closed pools of words, and (3) using stimuli from a language other than English. In both experiments, words from large neighborhoods were better recalled than words from small neighborhoods. The results add to the growing number of studies demonstrating the substantial contribution of long-term memory to what have traditionally been identified as working memory tasks. The data are more easily explained by models incorporating the concept of redintegration rather than by frameworks such as the phonological loop that posit decay offset by rehearsal. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  12. The effects of fluvial transport on radionuclide concentrations on different particle size classes

    International Nuclear Information System (INIS)

    Dyer, F.J.; Olley, J.M.

    1998-01-01

    This paper reports on the effects of grain abrasion and disaggregation on the distribution of 137 Cs with respect to particle size and the effects this may have on the use of 137 Cs for determining the origin of recent sediment. Cs-137 is a product of above ground nuclear testing and has been deposited on the earth's surface by rainfall. On contact with soil, 137 Cs is strongly adsorbed by soil particles and there is a direct correlation between 137 Cs concentration and decreasing particle size. Rapid adsorption means that 137 Cs is preferentially concentrated in surface soils, and it's subsequent redistribution by physical processes rather than chemical has lead to 137 Cs being widely used to study soil erosion

  13. The Precision of Effect Size Estimation From Published Psychological Research: Surveying Confidence Intervals.

    Science.gov (United States)

    Brand, Andrew; Bradley, Michael T

    2016-02-01

    Confidence interval ( CI) widths were calculated for reported Cohen's d standardized effect sizes and examined in two automated surveys of published psychological literature. The first survey reviewed 1,902 articles from Psychological Science. The second survey reviewed a total of 5,169 articles from across the following four APA journals: Journal of Abnormal Psychology, Journal of Applied Psychology, Journal of Experimental Psychology: Human Perception and Performance, and Developmental Psychology. The median CI width for d was greater than 1 in both surveys. Hence, CI widths were, as Cohen (1994) speculated, embarrassingly large. Additional exploratory analyses revealed that CI widths varied across psychological research areas and that CI widths were not discernably decreasing over time. The theoretical implications of these findings are discussed along with ways of reducing the CI widths and thus improving precision of effect size estimation.

  14. Numerical Evaluation of Size Effect on the Stress-Strain Behaviour of Geotextile-Reinforced Sand

    DEFF Research Database (Denmark)

    Hosseinpour, I.; Mirmoradi, S.H.; Barari, Amin

    2010-01-01

    This paper studies the effect of sample size on the stress-strain behavior and strength characteristics of geotextile reinforced sand using the finite element numerical analysis. The effect of sample size was investigated by studying the effects of varying the number of geotextile layers, the con......This paper studies the effect of sample size on the stress-strain behavior and strength characteristics of geotextile reinforced sand using the finite element numerical analysis. The effect of sample size was investigated by studying the effects of varying the number of geotextile layers...... on the mechanical behavior of reinforced sand decreases with an increase in the sample size....

  15. The effect of size on the oxygen electroreduction activity of mass-selected platinum nanoparticles

    DEFF Research Database (Denmark)

    Pérez Alonso, Francisco; McCarthy, David N; Nierhoff, Anders

    2012-01-01

    A matter of size: The particle size effect on the activity of the oxygen reduction reaction of size-selected platinum clusters was studied. The ORR activity decreased with decreasing Pt nanoparticle size, corresponding to a decrease in the fraction of terraces on the surfaces of the Pt nanopartic...

  16. The Effect of Size on the Oxygen Electroreduction Activity of Mass‐Selected Platinum Nanoparticles

    DEFF Research Database (Denmark)

    Pérez Alonso, Francisco; McCarthy, David Norman; Nierhoff, Anders Ulrik Fregerslev

    2012-01-01

    A matter of size: The particle size effect on the activity of the oxygen reduction reaction of size-selected platinum clusters was studied. The ORR activity decreased with decreasing Pt nanoparticle size, corresponding to a decrease in the fraction of terraces on the surfaces of the Pt nanopartic...

  17. Effects of climate on size structure and functioning of aquatic food webs

    NARCIS (Netherlands)

    Lacerot, G.

    2010-01-01

    In aquatic food webs, the role of body size is notoriously strong. It is also well known that temperature has an effect on body size. For instance, Bergmann’s rule states that body size increases from warm to cold climates. This thesis addresses the question how climate shapes the size structure of

  18. Effect of beamlet step-size on IMRT plan quality

    International Nuclear Information System (INIS)

    Zhang Guowei; Jiang Ziping; Shepard, David; Earl, Matt; Yu, Cedric

    2005-01-01

    We have studied the degree to which beamlet step-size impacts the quality of intensity modulated radiation therapy (IMRT) treatment plans. Treatment planning for IMRT begins with the application of a grid that divides each beam's-eye-view of the target into a number of smaller beamlets (pencil beams) of radiation. The total dose is computed as a weighted sum of the dose delivered by the individual beamlets. The width of each beamlet is set to match the width of the corresponding leaf of the multileaf collimator (MLC). The length of each beamlet (beamlet step-size) is parallel to the direction of leaf travel. The beamlet step-size represents the minimum stepping distance of the leaves of the MLC and is typically predetermined by the treatment planning system. This selection imposes an artificial constraint because the leaves of the MLC and the jaws can both move continuously. Removing the constraint can potentially improve the IMRT plan quality. In this study, the optimized results were achieved using an aperture-based inverse planning technique called direct aperture optimization (DAO). We have tested the relationship between pencil beam step-size and plan quality using the American College of Radiology's IMRT test case. For this case, a series of IMRT treatment plans were produced using beamlet step-sizes of 1, 2, 5, and 10 mm. Continuous improvements were seen with each reduction in beamlet step size. The maximum dose to the planning target volume (PTV) was reduced from 134.7% to 121.5% and the mean dose to the organ at risk (OAR) was reduced from 38.5% to 28.2% as the beamlet step-size was reduced from 10 to 1 mm. The smaller pencil beam sizes also led to steeper dose gradients at the junction between the target and the critical structure with gradients of 6.0, 7.6, 8.7, and 9.1 dose%/mm achieved for beamlet step sizes of 10, 5, 2, and 1 mm, respectively

  19. Effect of silica particle size on macrophage inflammatory responses.

    Directory of Open Access Journals (Sweden)

    Toshimasa Kusaka

    Full Text Available Amorphous silica particles, such as nanoparticles (<100 nm diameter particles, are used in a wide variety of products, including pharmaceuticals, paints, cosmetics, and food. Nevertheless, the immunotoxicity of these particles and the relationship between silica particle size and pro-inflammatory activity are not fully understood. In this study, we addressed the relationship between the size of amorphous silica (particle dose, diameter, number, and surface area and the inflammatory activity (macrophage phagocytosis, inflammasome activation, IL-1β secretion, cell death and lung inflammation. Irrespective of diameter size, silica particles were efficiently internalized by mouse bone marrow-derived macrophages via an actin cytoskeleton-dependent pathway, and induced caspase-1, but not caspase-11, activation. Of note, 30 nm-1000 nm diameter silica particles induced lysosomal destabilization, cell death, and IL-1β secretion at markedly higher levels than did 3000 nm-10000 nm silica particles. Consistent with in vitro results, intra-tracheal administration of 30 nm silica particles into mice caused more severe lung inflammation than that of 3000 nm silica particles, as assessed by measurement of pro-inflammatory cytokines and neutrophil infiltration in bronchoalveolar lavage fluid of mice, and by the micro-computed tomography analysis. Taken together, these results suggest that silica particle size impacts immune responses, with submicron amorphous silica particles inducing higher inflammatory responses than silica particles over 1000 nm in size, which is ascribed not only to their ability to induce caspase-1 activation but also to their cytotoxicity.

  20. Wollastonite Carbonation in Water-Bearing Supercritical CO2: Effects of Particle Size.

    Science.gov (United States)

    Min, Yujia; Li, Qingyun; Voltolini, Marco; Kneafsey, Timothy; Jun, Young-Shin

    2017-11-07

    The performance of geologic CO 2 sequestration (GCS) can be affected by CO 2 mineralization and changes in the permeability of geologic formations resulting from interactions between water-bearing supercritical CO 2 (scCO 2 ) and silicates in reservoir rocks. However, without an understanding of the size effects, the findings in previous studies using nanometer- or micrometer-size particles cannot be applied to the bulk rock in field sites. In this study, we report the effects of particle sizes on the carbonation of wollastonite (CaSiO 3 ) at 60 °C and 100 bar in water-bearing scCO 2 . After normalization by the surface area, the thickness of the reacted wollastonite layer on the surfaces was independent of particle sizes. After 20 h, the reaction was not controlled by the kinetics of surface reactions but by the diffusion of water-bearing scCO 2 across the product layer on wollastonite surfaces. Among the products of reaction, amorphous silica, rather than calcite, covered the wollastonite surface and acted as a diffusion barrier to water-bearing scCO 2 . The product layer was not highly porous, with a specific surface area 10 times smaller than that of the altered amorphous silica formed at the wollastonite surface in aqueous solution. These findings can help us evaluate the impacts of mineral carbonation in water-bearing scCO 2 .

  1. High temporal resolution in situ measurement of the effective particle size characteristics of fluvial suspended sediment.

    Science.gov (United States)

    Williams, N D; Walling, D E; Leeks, G J L

    2007-03-01

    This paper reports the use of a LISST-100 device to monitor the effective particle size characteristics of suspended sediment in situ, and at a quasi-continuous temporal resolution. The study site was located on the River Exe at Thorverton, Devon, UK. This device has not previously been utilized in studies of fluvial suspended sediment at the storm event scale, and existing studies of suspended sediment dynamics have not involved such a high temporal resolution for extended periods. An evaluation of the field performance of the instrument is presented, with respect to innovative data collection and analysis techniques. It was found that trends in the effective particle size distribution (EPSD) and degree of flocculation of suspended sediment at the study site were highly complex, and showed significant short-term variability that has not previously been documented in the fluvial environment. The collection of detailed records of EPSD facilitated interpretation of the dynamic evolution of the size characteristics of suspended sediment, in relation to its likely source and delivery and flocculation mechanisms. The influence of measurement frequency is considered in terms of its implications for future studies of the particle size of fluvial suspended sediment employing in situ data acquisition.

  2. Seed size effects on the response of seedlings of Acacia asak (Forssk.) Willd to water stress

    International Nuclear Information System (INIS)

    El Atta, H.A.; Areef, I.M.; Ahmed, A.I.

    2016-01-01

    Dry tropical forests are characterized by unpredictable spells of drought and climate change. Saudi Arabia mostly falls within the arid zone and some few scattered areas fall in the semiarid zone mainly in the South Western region. Rainfall is sparse and with sporadic distribution. Drought is the most critical factor for restoration of the tree cover. Within a tree, seeds vary in size from large to small seeds. Although several researchers have studied the effect of within species variation in seed size on seedlings growth parameters, however there is a lack of knowledge regarding the effect of seed size on stress tolerance (Khurana and Singh 2000). We assumed that seedlings grown from different seed sizes from the same tree species may influence their response to water stress. Seeds of Acacia asak (Forssk.) Willd. were categorized into large, medium and small seeds on the basis of the seed weight. Seedlings from the three seed sizes were grown in potted soil and subjected to 5 levels of field water capacity (FC) (100, 75, 50, 25 and 15 percent) in the greenhouse. The Objective was to evaluate the response of seedling grown (from different seed sizes) to water stress and to understand the acclimation of seedlings to water stress. Water stress significantly reduced RWC, leaf area, and shoot length, fresh and dry weight. Significant correlations between growth parameters and water stress level were recorded. Seedlings from large seeds were heavier and comparatively less affected by drought compared to seedlings from smaller seeds. In all seedlings root length increased significantly and more biomass was allocated to roots than to shoots. However, at severe water stress (15 percent FC) no significant differences were reported between the three seedling categories. Therefore, raising of seedlings from large seeds is more appropriate for tree restoration programs under drought conditions. (author)

  3. Bottom-up and top-down attentional contributions to the size congruity effect.

    Science.gov (United States)

    Sobel, Kenith V; Puri, Amrita M; Faulkenberry, Thomas J

    2016-07-01

    The size congruity effect refers to the interaction between the numerical and physical (i.e., font) sizes of digits in a numerical (or physical) magnitude selection task. Although various accounts of the size congruity effect have attributed this interaction to either an early representational stage or a late decision stage, only Risko, Maloney, and Fugelsang (Attention, Perception, & Psychophysics, 75, 1137-1147, 2013) have asserted a central role for attention. In the present study, we used a visual search paradigm to further study the role of attention in the size congruity effect. In Experiments 1 and 2, we showed that manipulating top-down attention (via the task instructions) had a significant impact on the size congruity effect. The interaction between numerical and physical size was larger for numerical size comparison (Exp. 1) than for physical size comparison (Exp. 2). In the remaining experiments, we boosted the feature salience by using a unique target color (Exp. 3) or by increasing the display density by using three-digit numerals (Exps. 4 and 5). As expected, a color singleton target abolished the size congruity effect. Searching for three-digit targets based on numerical size (Exp. 4) resulted in a large size congruity effect, but search based on physical size (Exp. 5) abolished the effect. Our results reveal a substantial role for top-down attention in the size congruity effect, which we interpreted as support for a shared-decision account.

  4. Size effect on magnetic ordering in Ce3Al11

    International Nuclear Information System (INIS)

    Wang, C.R.; Chen, Y.Y.; Neeleshwar, S.; Ou, M.N.; Ho, J.C.

    2003-01-01

    To study the size dependence of magnetic ordering, magnetic measurements have been made between 1.8 and 300 K on Ce 3 Al 11 particles having an average particle size of 1400 A. The nanoparticles were single phase as confirmed by X-ray diffraction. At low temperatures a ferromagnetic transition occurs at T C =6.2 K, which is the same as that for the bulk material. On the other hand, the antiferromagnetic transition at T N =3.2 K for the bulk material is not visible down to 1.8 K. Meanwhile, the slightly smaller Curie constant of nanoparticles as compared to that of the bulk indicates a certain degree of demagnetization of Ce ions when the particle size is sufficiently reduced

  5. Effectiveness of strategies to increase the validity of findings from association studies: size vs. replication

    Directory of Open Access Journals (Sweden)

    Kallischnigg Gerd

    2010-05-01

    Full Text Available Abstract Background The capacity of multiple comparisons to produce false positive findings in genetic association studies is abundantly clear. To address this issue, the concept of false positive report probability (FPRP measures "the probability of no true association between a genetic variant and disease given a statistically significant finding". This concept involves the notion of prior probability of an association between a genetic variant and a disease, making it difficult to achieve acceptable levels for the FPRP when the prior probability is low. Increasing the sample size is of limited efficiency to improve the situation. Methods To further clarify this problem, the concept of true report probability (TRP is introduced by analogy to the positive predictive value (PPV of diagnostic testing. The approach is extended to consider the effects of replication studies. The formula for the TRP after k replication studies is mathematically derived and shown to be only dependent on prior probability, alpha, power, and number of replication studies. Results Case-control association studies are used to illustrate the TRP concept for replication strategies. Based on power considerations, a relationship is derived between TRP after k replication studies and sample size of each individual study. That relationship enables study designers optimization of study plans. Further, it is demonstrated that replication is efficient in increasing the TRP even in the case of low prior probability of an association and without requiring very large sample sizes for each individual study. Conclusions True report probability is a comprehensive and straightforward concept for assessing the validity of positive statistical testing results in association studies. By its extension to replication strategies it can be demonstrated in a transparent manner that replication is highly effective in distinguishing spurious from true associations. Based on the generalized TRP

  6. Effects of grain size evolution on mantle dynamics

    Science.gov (United States)

    Schulz, Falko; Tosi, Nicola; Plesa, Ana-Catalina; Breuer, Doris

    2016-04-01

    The rheology of planetary mantle materials is strongly dependent on temperature, pressure, strain-rate, and grain size. In particular, the rheology of olivine, the most abundant mineral of the Earth's upper mantle, has been extensively studied in the laboratory (e.g., Karato and Wu, 1993; Hirth and Kohlstedt, 2003). Two main mechanisms control olivine's deformation: dislocation and diffusion creep. While the former implies a power-law dependence of the viscosity on the strain-rate that leads to a non-Newtonian behaviour, the latter is sensitively dependent on the grain size. The dynamics of planetary interiors is locally controlled by the deformation mechanism that delivers the lowest viscosity. Models of the dynamics and evolution of planetary mantles should thus be capable to self-consistently distinguish which of the two mechanisms dominates at given conditions of temperature, pressure, strain-rate and grain size. As the grain size can affect the viscosity associated with diffusion creep by several orders of magnitude, it can strongly influence the dominant deformation mechanism. The vast majority of numerical, global-scale models of mantle convection, however, are based on the use of a linear diffusion-creep rheology with constant grain-size. Nevertheless, in recent studies, a new equation has been proposed to properly model the time-dependent evolution of the grain size (Austin and Evens, 2007; Rozel et al., 2010). We implemented this equation in our mantle convection code Gaia (Hüttig et al., 2013). In the framework of simple models of stagnant lid convection, we compared simulations based on the fully time-dependent equation of grain-size evolution with simulations based on its steady-state version. In addition, we tested a number of different parameters in order to identify those that affects the grain size to the first order and, in turn, control the conditions at which mantle deformation is dominated by diffusion or dislocation creep. References Austin

  7. Finite size effects for giant magnons on physical strings

    International Nuclear Information System (INIS)

    Minahan, J.A.; Ohlsson Sax, O.

    2008-01-01

    Using finite gap methods, we find the leading order finite size corrections for an arbitrary number of giant magnons on physical strings, where the sum of the momenta is a multiple of 2π. Our results are valid for the Hofman-Maldacena fundamental giant magnons as well as their dyonic generalizations. The energy corrections turn out to be surprisingly simple, especially if all the magnons are fundamental, and at leading order are independent of the magnon flavors. We also show how to use the Bethe ansatz to find finite size corrections for dyonic giant magnons with large R-charges

  8. Effect Size Analyses of Souvenaid in Patients with Alzheimer’s Disease

    Science.gov (United States)

    Cummings, Jeffrey; Scheltens, Philip; McKeith, Ian; Blesa, Rafael; Harrison, John E.; Bertolucci, Paulo H.F.; Rockwood, Kenneth; Wilkinson, David; Wijker, Wouter; Bennett, David A.; Shah, Raj C.

    2016-01-01

    Background: Souvenaid® (uridine monophosphate, docosahexaenoic acid, eicosapentaenoic acid, choline, phospholipids, folic acid, vitamins B12, B6, C, and E, and selenium), was developed to support the formation and function of neuronal membranes. Objective: To determine effect sizes observed in clinical trials of Souvenaid and to calculate the number needed to treat to show benefit or harm. Methods: Data from all three reported randomized controlled trials of Souvenaid in Alzheimer’s disease (AD) dementia (Souvenir I, Souvenir II, and S-Connect) and an open-label extension study were included in analyses of effect size for cognitive, functional, and behavioral outcomes. Effect size was determined by calculating Cohen’s d statistic (or Cramér’s V method for nominal data), number needed to treat and number needed to harm. Statistical calculations were performed for the intent-to-treat populations. Results: In patients with mild AD, effect sizes were 0.21 (95% confidence intervals: –0.06, 0.49) for the primary outcome in Souvenir II (neuropsychological test battery memory z-score) and 0.20 (0.10, 0.34) for the co-primary outcome of Souvenir I (Wechsler memory scale delayed recall). No effect was shown on cognition in patients with mild-to-moderate AD (S-Connect). The number needed to treat (6 and 21 for Souvenir I and II, respectively) and high number needed to harm values indicate a favorable harm:benefit ratio for Souvenaid versus control in patients with mild AD. Conclusions: The favorable safety profile and impact on outcome measures converge to corroborate the putative mode of action and demonstrate that Souvenaid can achieve clinically detectable effects in patients with early AD. PMID:27767993

  9. Intriguing structures and magic sizes of heavy noble metal nanoclusters around size 55 governed by relativistic effect and covalent bonding

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, X. J.; Xue, X. L.; Jia, Yu [International Laboratory for Quantum Functional Materials of Henan and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Guo, Z. X. [International Laboratory for Quantum Functional Materials of Henan and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001 (China); Department of Chemistry and London Centre for Nanotechnology, University College London, London WC1H (United Kingdom); Li, S. F., E-mail: sflizzu@zzu.edu.cn [International Laboratory for Quantum Functional Materials of Henan and School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001 (China); ICQD, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Zhenyu, E-mail: zhangzy@ustc.edu.cn [ICQD, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Gao, Y. F., E-mail: ygao7@utk.edu [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-11-07

    Nanoclusters usually display exotic physical and chemical properties due to their intriguing geometric structures in contrast to their bulk counterparts. By means of first-principles calculations within density functional theory, we find that heavy noble metal Pt{sub N} nanoclusters around the size N = 55 begin to prefer an open configuration, rather than previously reported close-packed icosahedron or core-shell structures. Particularly, for Pt{sub N}, the widely supposed icosahedronal magic cluster is changed to a three-atomic-layered structure with D{sub 6h} symmetry, which can be well addressed by our recently established generalized Wulff construction principle (GWCP). However, the magic number of Pt{sub N} clusters around 55 is shifted to a new odd number of 57. The high symmetric three-layered Pt{sub 57} motif is mainly stabilized by the enhanced covalent bonding contributed by both spin-orbital coupling effect and the open d orbital (5d{sup 9}6s{sup 1}) of Pt, which result in a delicate balance between the enhanced Pt–Pt covalent bonding of the interlayers and negligible d dangling bonds on the cluster edges. These findings about Pt{sub N} clusters are also applicable to Ir{sub N} clusters, but qualitatively different from their earlier neighboring element Os and their later neighboring element Au. The magic numbers for Os and Au are even, being 56 and 58, respectively. The findings of the new odd magic number 57 are the important supplementary of the recently established GWCP.

  10. Duration of Load Effects on Different Sized Timber Beams

    DEFF Research Database (Denmark)

    Andreasen, Lotte; Hoffmeyer, Preben

    1997-01-01

    This is the final report submitted to EC in connection with a project on duration of load. The report contains the results of the experimental work on duration of load for beams and notched beams of LVL and of glulam. The report also contains experimental results from duration of load experiments...

  11. Gravity and Heater Size Effects on Pool Boiling Heat Transfer

    Science.gov (United States)

    Kim, Jungho; Raj, Rishi

    2014-01-01

    The current work is based on observations of boiling heat transfer over a continuous range of gravity levels between 0g to 1.8g and varying heater sizes with a fluorinert as the test liquid (FC-72/n-perfluorohexane). Variable gravity pool boiling heat transfer measurements over a wide range of gravity levels were made during parabolic flight campaigns as well as onboard the International Space Station. For large heaters and-or higher gravity conditions, buoyancy dominated boiling and heat transfer results were heater size independent. The power law coefficient for gravity in the heat transfer equation was found to be a function of wall temperature under these conditions. Under low gravity conditions and-or for smaller heaters, surface tension forces dominated and heat transfer results were heater size dependent. A pool boiling regime map differentiating buoyancy and surface tension dominated regimes was developed along with a unified framework that allowed for scaling of pool boiling over a wide range of gravity levels and heater sizes. The scaling laws developed in this study are expected to allow performance quantification of phase change based technologies under variable gravity environments eventually leading to their implementation in space based applications.

  12. Effects of plot size on forest-type algorithm accuracy

    Science.gov (United States)

    James A. Westfall

    2009-01-01

    The Forest Inventory and Analysis (FIA) program utilizes an algorithm to consistently determine the forest type for forested conditions on sample plots. Forest type is determined from tree size and species information. Thus, the accuracy of results is often dependent on the number of trees present, which is highly correlated with plot area. This research examines the...

  13. Effects of Morphological Family Size for Young Readers

    Science.gov (United States)

    Perdijk, Kors; Schreuder, Robert; Baayen, R. Harald; Verhoeven, Ludo

    2012-01-01

    Dutch children, from the second and fourth grade of primary school, were each given a visual lexical decision test on 210 Dutch monomorphemic words. After removing words not recognized by a majority of the younger group, (lexical) decisions were analysed by mixed-model regression methods to see whether morphological Family Size influenced decision…

  14. Effect of population size on prospect of species survival

    Czech Academy of Sciences Publication Activity Database

    Münzbergová, Zuzana

    2006-01-01

    Roč. 41, - (2006), s. 137-150 ISSN 1211-9520 R&D Projects: GA AV ČR KJB6111303 Institutional research plan: CEZ:AV0Z60050516 Keywords : population * size * survival Subject RIV: EF - Botanics Impact factor: 1.196, year: 2006

  15. Size effect in self consolidating concrete beams with and without ...

    Indian Academy of Sciences (India)

    the decrease in nominal stress of notched beam is more when compared with that ... The differences between HPC and SCC is essentially in the use of special .... elements fail in ductile or plastic manner, while large sized elements of the ...

  16. The Effect of Organizational Size on Sport Centers' Employees Burnout.

    Directory of Open Access Journals (Sweden)

    ATHANASIOS KOUSTELIOS

    2009-01-01

    Full Text Available Organizational size and its relation with burnout were examined among 163 sport centres employees in Greece. Findings showed that there is a significant difference on employees' burnout between small and large sport organizations. Particularly, it was found that employees in small sport organizations experienced lower level of Emotional Exhaustion (p<.05 and higher level of Personal Accomplishment (p<.005.

  17. The effects of gold nanoparticles size and concentration on viscosity ...

    African Journals Online (AJOL)

    This study was carried out to investigate viscosity in relation with the temperature, flow activation energy and dielectric properties for 10, 20 and 50 nm gold nanoparticles size (GNPs) in addition to absorption and fluorescence spectra at different concentrations (0.2 × 10-3 to 1 × 10-2%) in an attempt to cover and understand ...

  18. The Effects of Rain Garden Size on Hydrologic Performance

    Science.gov (United States)

    Rain gardens are vegetated depressions designed to accept stormwater runoff. Manuals and guidance documents recommend sizing rain garden cells from 3% to 43% of the associated drainage area, based on factors including soil type, slope, amount of impervious cover in the drainage ...

  19. Effect of particle size on iron nanoparticle oxidation state

    International Nuclear Information System (INIS)

    Lombardo, Jeffrey J.; Lysaght, Andrew C.; Goberman, Daniel G.; Chiu, Wilson K.S.

    2012-01-01

    Selecting catalyst particles is a very important part of carbon nanotube growth, although the properties of these nanoscale particles are unclear. In this article iron nanoparticles are analyzed through the use of atomic force microscopy and x-ray photoelectron spectroscopy in order to understand how the size affects the chemical composition of nanoparticles and thus their physical structure. Initially, atomic force microscopy was used to confirm the presence of iron particles, and to determine the average size of the particles. Next an analytical model was developed to estimate particle size as a function of deposition time using inputs from atomic force microscopy measurement. X-ray photoelectron spectroscopy analysis was then performed with a focus on the spectra relating to the 2p Fe electrons to study the chemical state of the particles as a function of time. It was shown that as the size of nanoparticles decreased, the oxidation state of the particles changed due to a high proportion of atoms on the surface.

  20. Finite-Size Effects for Some Bootstrap Percolation Models

    NARCIS (Netherlands)

    Enter, A.C.D. van; Adler, Joan; Duarte, J.A.M.S.

    The consequences of Schonmann's new proof that the critical threshold is unity for certain bootstrap percolation models are explored. It is shown that this proof provides an upper bound for the finite-size scaling in these systems. Comparison with data for one case demonstrates that this scaling

  1. Size effect of the elastic modulus of rectangular nanobeams: Surface elasticity effect

    International Nuclear Information System (INIS)

    Yao Hai-Yan; Fan Wen-Liang; Yun Guo-Hong

    2013-01-01

    The size-dependent elastic property of rectangular nanobeams (nanowires or nanoplates) induced by the surface elasticity effect is investigated by using a developed modified core-shell model. The effect of surface elasticity on the elastic modulus of nanobeams can be characterized by two surface related parameters, i.e., inhomogeneous degree constant and surface layer thickness. The analytical results show that the elastic modulus of the rectangular nanobeam exhibits a distinct size effect when its characteristic size reduces below 100 nm. It is also found that the theoretical results calculated by a modified core-shell model have more obvious advantages than those by other models (core-shell model and core-surface model) by comparing them with relevant experimental measurements and computational results, especially when the dimensions of nanostructures reduce to a few tens of nanometers. (condensed matter: structural, mechanical, and thermal properties)

  2. The Role of Social Norms in the Portion Size Effect: Reducing normative relevance reduces the effect of portion size on consumption decisions

    Directory of Open Access Journals (Sweden)

    Iris eVersluis

    2016-05-01

    Full Text Available People typically eat more from large portions of food than from small portions. An explanation that has often been given for this so-called portion size effect is that the portion size acts as a social norm and as such communicates how much is appropriate to eat. In this paper, we tested this explanation by examining whether manipulating the relevance of the portion size as a social norm changes the portion size effect, as assessed by prospective consumption decisions. We conducted one pilot experiment and one full experiment in which participants respectively indicated how much they would eat or serve themselves from a given amount of different foods. In the pilot (N = 63, we manipulated normative relevance by allegedly basing the portion size on the behavior of either students of the own university (in-group or of another university (out-group. In the main experiment (N = 321, we told participants that either a minority or majority of people similar to them approved of the portion size. Results show that in both experiments, participants expected to serve themselves and to eat more from larger than from smaller portions. As expected, however, the portion size effect was less pronounced when the reference portions were allegedly based on the behavior of an out-group (pilot or approved only by a minority (main experiment. These findings suggest that the portion size indeed provides normative information, because participants were less influenced by it if it communicated the behaviors or values of a less relevant social group. In addition, in the main experiment, the relation between portion size and the expected amount served was partially mediated by the amount that was considered appropriate, suggesting that concerns about eating an appropriate amount indeed play a role in the portion size effect. However, since the portion size effect was weakened but not eliminated by the normative relevance manipulations and since mediation was only partial

  3. Self-Reported Penis Size and Experiences with Condoms Among Gay and Bisexual Men

    Science.gov (United States)

    Grov, Christian; Wells, Brooke E.

    2018-01-01

    As researchers and community-based providers continue to encourage latex condom use as a chief strategy to prevent HIV transmission among men who have sex with men, research is needed to better explore the intersecting associations among penis size (length and circumference), condom feel, ease of finding condoms, recent experience of condom failure (breakage and slippage), and unprotected anal sex. Data were taken from a 2010 community-based survey of self-identified gay and bisexual men in New York City (n = 463). More than half (51.4 %) reported penile length as 6–8 in. long (15–20 cm) and 31.5 % reported penile circumference as 4–6 in. around (10–15 cm). Variation in self-reported penile dimensions was significantly associated with men’s attitudes toward the typical/average condom, difficulty finding condoms that fit, and the experience of condom breakage. Men who had engaged in recent unprotected insertive anal intercourse reported significantly higher values for both penile length and circumference, and these men were significantly more likely to report that the average/typical condom was “too tight.” Most men had measured their length (86.2 %) and/or circumference (68.9 %), suggesting that penile measurement might be a common and acceptable practice among gay and bisexual men. As HIV and STI prevention providers continue to serve as leading distributers of free condoms, these findings further highlight the need for condom availability to be in a variety of sizes. Improving condom fit and attitudes toward condoms may also improve condom use and minimize condom slippage and breakage. PMID:22552706

  4. Estimating Divergence Time and Ancestral Effective Population Size of Bornean and Sumatran Orangutan Subspecies Using a Coalescent Hidden Markov Model

    DEFF Research Database (Denmark)

    Mailund, Thomas; Dutheil, Julien; Hobolth, Asger

    2011-01-01

    event has occurred to split them apart. The size of these segments of constant divergence depends on the recombination rate, but also on the speciation time, the effective population size of the ancestral population, as well as demographic effects and selection. Thus, inference of these parameters may......, and the ancestral effective population size. The model is efficient enough to allow inference on whole-genome data sets. We first investigate the power and consistency of the model with coalescent simulations and then apply it to the whole-genome sequences of the two orangutan sub-species, Bornean (P. p. pygmaeus......) and Sumatran (P. p. abelii) orangutans from the Orangutan Genome Project. We estimate the speciation time between the two sub-species to be thousand years ago and the effective population size of the ancestral orangutan species to be , consistent with recent results based on smaller data sets. We also report...

  5. Atherogenic lipoprotein particle size and concentrations and the effect of pravastatin in children with familial hypercholesterolemia

    NARCIS (Netherlands)

    van der Graaf, Anouk; Rodenburg, Jessica; Vissers, Maud N.; Hutten, Barbara A.; Wiegman, Albert; Trip, Mieke D.; Stroes, Erik S. G.; Wijburg, Frits A.; Otvos, James D.; Kastelein, John J. P.

    2008-01-01

    OBJECTIVE: To determine lipoprotein particle concentrations and size in children with familial hypercholesterolemia (FH) and investigate the effect of pravastatin therapy on these measures. STUDY DESIGN: Lipoprotein particle concentrations and sizes were examined by nuclear magnetic resonance (NMR)

  6. Population genomics of eusocial insects: the costs of a vertebrate-like effective population size.

    Science.gov (United States)

    Romiguier, J; Lourenco, J; Gayral, P; Faivre, N; Weinert, L A; Ravel, S; Ballenghien, M; Cahais, V; Bernard, A; Loire, E; Keller, L; Galtier, N

    2014-03-01

    The evolution of reproductive division of labour and social life in social insects has lead to the emergence of several life-history traits and adaptations typical of larger organisms: social insect colonies can reach masses of several kilograms, they start reproducing only when they are several years old, and can live for decades. These features and the monopolization of reproduction by only one or few individuals in a colony should affect molecular evolution by reducing the effective population size. We tested this prediction by analysing genome-wide patterns of coding sequence polymorphism and divergence in eusocial vs. noneusocial insects based on newly generated RNA-seq data. We report very low amounts of genetic polymorphism and an elevated ratio of nonsynonymous to synonymous changes – a marker of the effective population size – in four distinct species of eusocial insects, which were more similar to vertebrates than to solitary insects regarding molecular evolutionary processes. Moreover, the ratio of nonsynonymous to synonymous substitutions was positively correlated with the level of social complexity across ant species. These results are fully consistent with the hypothesis of a reduced effective population size and an increased genetic load in eusocial insects, indicating that the evolution of social life has important consequences at both the genomic and population levels. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  7. Performance Optimization of Irreversible Air Heat Pumps Considering Size Effect

    Science.gov (United States)

    Bi, Yuehong; Chen, Lingen; Ding, Zemin; Sun, Fengrui

    2018-06-01

    Considering the size of an irreversible air heat pump (AHP), heating load density (HLD) is taken as thermodynamic optimization objective by using finite-time thermodynamics. Based on an irreversible AHP with infinite reservoir thermal-capacitance rate model, the expression of HLD of AHP is put forward. The HLD optimization processes are studied analytically and numerically, which consist of two aspects: (1) to choose pressure ratio; (2) to distribute heat-exchanger inventory. Heat reservoir temperatures, heat transfer performance of heat exchangers as well as irreversibility during compression and expansion processes are important factors influencing on the performance of an irreversible AHP, which are characterized with temperature ratio, heat exchanger inventory as well as isentropic efficiencies, respectively. Those impacts of parameters on the maximum HLD are thoroughly studied. The research results show that HLD optimization can make the size of the AHP system smaller and improve the compactness of system.

  8. Dust generation in powders: Effect of particle size distribution

    Directory of Open Access Journals (Sweden)

    Chakravarty Somik

    2017-01-01

    Full Text Available This study explores the relationship between the bulk and grain-scale properties of powders and dust generation. A vortex shaker dustiness tester was used to evaluate 8 calcium carbonate test powders with median particle sizes ranging from 2μm to 136μm. Respirable aerosols released from the powder samples were characterised by their particle number and mass concentrations. All the powder samples were found to release respirable fractions of dust particles which end up decreasing with time. The variation of powder dustiness as a function of the particle size distribution was analysed for the powders, which were classified into three groups based on the fraction of particles within the respirable range. The trends we observe might be due to the interplay of several mechanisms like de-agglomeration and attrition and their relative importance.

  9. An engineering method for estimating notch-size effect in fatigue tests on steel

    Science.gov (United States)

    Kuhn, Paul; Hardrath, Herbert F

    1952-01-01

    Neuber's proposed method of calculating a practical factor of stress concentration for parts containing notches of arbitrary size depends on the knowledge of a "new material constant" which can be established only indirectly. In this paper, the new constant has been evaluated for a large variety of steels from fatigue tests reported in the literature, attention being confined to stresses near the endurance limit. Reasonably satisfactory results were obtained with the assumption that the constant depends only on the tensile strength of the steel. Even in cases where the notches were cracks of which only the depth was known, reasonably satisfactory agreement was found between calculated and experimental factors. It is also shown that the material constant can be used in an empirical formula to estimate the size effect on unnotched specimens tested in bending fatigue.

  10. Curriculum-Based Handwriting Programs: A Systematic Review With Effect Sizes

    Science.gov (United States)

    Engel, Courtney; Lillie, Kristin; Zurawski, Sarah; Travers, Brittany G.

    2018-01-01

    Challenges with handwriting can have a negative impact on academic performance, and these challenges are commonly addressed by occupational therapy practitioners in school settings. This systematic review examined the efficacy of curriculum-based interventions to address children’s handwriting difficulties in the classroom (preschool to second grade). We reviewed and computed effect sizes for 13 studies (11 Level II, 2 Level III) identified through a comprehensive database search. The evidence shows that curriculum-based handwriting interventions resulted in small- to medium-sized improvements in legibility, a commonly reported challenge in this age group. The evidence for whether these interventions improved speed is mixed, and the evidence for whether they improved fluency is insufficient. No clear support was found for one handwriting program over another. These results suggest that curriculum-based interventions can lead to improvements in handwriting legibility, but Level I research is needed to validate the efficacy of these curricula. PMID:29689170

  11. Effects of Mixtures on Liquid and Solid Fragment Size Distributions

    Science.gov (United States)

    2016-05-01

    bins, too few size bins, fixed bin widths, or inadequately- varying bin widths. Overpopulated bins – which typically occur for smaller fragments...2010 C. V. B. Cunningham, The Kuz-Ram Fragmentation Model – 20 Years On, In R. Holmberg et. al., Editors, Proceedings of the 3 rd World ...1992 P. K. Sahoo and T. Riedel, Mean Value Theorems and Functional Equations, World Scientific, 1998 K. A. Sallam, C. Aalburg, G.M. Faeth

  12. Local extinction and recolonization, species effective population size, and modern human origins.

    Science.gov (United States)

    Eller, Elise; Hawks, John; Relethford, John H

    2004-10-01

    A primary objection from a population genetics perspective to a multiregional model of modern human origins is that the model posits a large census size, whereas genetic data suggest a small effective population size. The relationship between census size and effective size is complex, but arguments based on an island model of migration show that if the effective population size reflects the number of breeding individuals and the effects of population subdivision, then an effective population size of 10,000 is inconsistent with the census size of 500,000 to 1,000,000 that has been suggested by archeological evidence. However, these models have ignored the effects of population extinction and recolonization, which increase the expected variance among demes and reduce the inbreeding effective population size. Using models developed for population extinction and recolonization, we show that a large census size consistent with the multiregional model can be reconciled with an effective population size of 10,000, but genetic variation among demes must be high, reflecting low interdeme migration rates and a colonization process that involves a small number of colonists or kin-structured colonization. Ethnographic and archeological evidence is insufficient to determine whether such demographic conditions existed among Pleistocene human populations, and further work needs to be done. More realistic models that incorporate isolation by distance and heterogeneity in extinction rates and effective deme sizes also need to be developed. However, if true, a process of population extinction and recolonization has interesting implications for human demographic history.

  13. The Effect of Masculinity/Femininity and Pupil Size on Rapid, Unconscious Appraisals of Male Facial Attractiveness

    OpenAIRE

    Fitzgerald, Kate

    2007-01-01

    Olsen and Marshuetz (2005) claim that attractiveness is such an important attribute that it can be appraised within 13ms, at an unconscious level. The current study aimed to replicate Olsen and Marshuetz's (2005) findings whilst introducing two previously reported cues of attractiveness as variables; facial masculinity/femininity and pupil size. If Olsen and Marshuetz's (2005) claims were correct, what effect would a variation in the masculinity/femininity or pupil size of a ...

  14. Egg size investment in superb fairy-wrens: helper effects are modulated by climate

    Science.gov (United States)

    Heinsohn, R. G.; Russell, A. F.; Kilner, R. M.

    2016-01-01

    Natural populations might exhibit resilience to changing climatic conditions if they already show adaptive flexibility in their reproductive strategies. In cooperative breeders, theory predicts that mothers with helpers should provide less care when environmental conditions are favourable, but maintain high investment when conditions are challenging. Here, we test for evidence of climate-mediated flexibility in maternal investment in the cooperatively breeding superb fairy-wren Malurus cyaneus. We focus on egg size because in this species egg size influences offspring size, and females reduce egg investment when there are helpers at the nest. We report that females lay larger eggs during dry, hot conditions. However, the effect of temperature is modulated by the presence of helpers: the average egg size of females with helpers is reduced during cooler conditions but increased during hot conditions relative to females without helpers. This appears to reflect plasticity in egg investment rather than among female differences. Analysis of maternal survival suggests that helped females are better able to withstand the costs of breeding in hot conditions than females without helpers. Our study suggests that females can use multiple, independent cues to modulate egg investment flexibly in a variable environment. PMID:27903872

  15. On the gradient plasticity approach to size effects. Pt. 1: reviews

    International Nuclear Information System (INIS)

    Malmberg, T.; Tsagrakis, I.; Eleftheriadis, I.; Aifantis, E.C.; Michigan Technol. Univ., Houghton, MI

    2001-03-01

    The influence of specimen size on the plastic deformation and failure behaviour of some metals and steels is considered. This size dependence issue relates to the question of the transferability of mechanical test results of geometrically similar scaled-down structural models to the full scale structures using similitude laws; but it concerns also the validity of small scale laboratory type test results and their use as a basis for the computational modelling of large scale components. In part I ''reviews'' of this report a restricted review of scaled experiments at room temperature of geometrically similar specimens is given. This refers to the initiation of yielding under non-uniform states of deformation and also to the plastic deformation and fracture of smooth tensile specimens. Among others, non-classical continuum mechanics theories have become a means to interpret size effects. Especially gradient concepts are of interest which enrich the classical plasticity theories by higher order spatial strain gradients. These model extensions implicate additional material parameters which can be associated with internal length scales characteristic for the material. In part I a brief review of several gradient theories of plasticity is also given, including both deformation and flow theories and a comparison of the original ''symmetric stress'' theory with the more recent ''asymmetric stress'' theory is provided. The forthcoming part II ''applications'' exemplifies to what extend strain gradient models can describe the size influence on the deformation behaviour. (orig.) [de

  16. Brain vs behavior: an effect size comparison of neuroimaging and cognitive studies of genetic risk for schizophrenia.

    LENUS (Irish Health Repository)

    Rose, Emma Jane

    2013-05-01

    Genetic variants associated with increased risk for schizophrenia (SZ) are hypothesized to be more penetrant at the level of brain structure and function than at the level of behavior. However, to date the relative sensitivity of imaging vs cognitive measures of these variants has not been quantified. We considered effect sizes associated with cognitive and imaging studies of 9 robust SZ risk genes (DAOA, DISC1, DTNBP1, NRG1, RGS4, NRGN, CACNA1C, TCF4, and ZNF804A) published between January 2005-November 2011. Summary data was used to calculate estimates of effect size for each significant finding. The mean effect size for each study was categorized as small, medium, or large and the relative frequency of each category was compared between modalities and across genes. Random effects meta-analysis was used to consider the impact of experimental methodology on effect size. Imaging studies reported mostly medium or large effects, whereas cognitive investigations commonly reported small effects. Meta-analysis confirmed that imaging studies were associated with larger effects. Effect size estimates were negatively correlated with sample size but did not differ as a function of gene nor imaging modality. These observations support the notion that SZ risk variants show larger effects, and hence greater penetrance, when characterized using indices of brain structure and function than when indexed by cognitive measures. However, it remains to be established whether this holds true for individual risk variants, imaging modalities, or cognitive functions, and how such effects may be mediated by a relationship with sample size and other aspects of experimental variability.

  17. Simple and cost-effective fabrication of size-tunable zinc oxide architectures by multiple size reduction technique

    Directory of Open Access Journals (Sweden)

    Hyeong-Ho Park, Xin Zhang, Seon-Yong Hwang, Sang Hyun Jung, Semin Kang, Hyun-Beom Shin, Ho Kwan Kang, Hyung-Ho Park, Ross H Hill and Chul Ki Ko

    2012-01-01

    Full Text Available We present a simple size reduction technique for fabricating 400 nm zinc oxide (ZnO architectures using a silicon master containing only microscale architectures. In this approach, the overall fabrication, from the master to the molds and the final ZnO architectures, features cost-effective UV photolithography, instead of electron beam lithography or deep-UV photolithography. A photosensitive Zn-containing sol–gel precursor was used to imprint architectures by direct UV-assisted nanoimprint lithography (UV-NIL. The resulting Zn-containing architectures were then converted to ZnO architectures with reduced feature sizes by thermal annealing at 400 °C for 1 h. The imprinted and annealed ZnO architectures were also used as new masters for the size reduction technique. ZnO pillars of 400 nm diameter were obtained from a silicon master with pillars of 1000 nm diameter by simply repeating the size reduction technique. The photosensitivity and contrast of the Zn-containing precursor were measured as 6.5 J cm−2 and 16.5, respectively. Interesting complex ZnO patterns, with both microscale pillars and nanoscale holes, were demonstrated by the combination of dose-controlled UV exposure and a two-step UV-NIL.

  18. Simple and cost-effective fabrication of size-tunable zinc oxide architectures by multiple size reduction technique

    International Nuclear Information System (INIS)

    Park, Hyeong-Ho; Hwang, Seon-Yong; Jung, Sang Hyun; Kang, Semin; Shin, Hyun-Beom; Kang, Ho Kwan; Ko, Chul Ki; Zhang Xin; Hill, Ross H; Park, Hyung-Ho

    2012-01-01

    We present a simple size reduction technique for fabricating 400 nm zinc oxide (ZnO) architectures using a silicon master containing only microscale architectures. In this approach, the overall fabrication, from the master to the molds and the final ZnO architectures, features cost-effective UV photolithography, instead of electron beam lithography or deep-UV photolithography. A photosensitive Zn-containing sol–gel precursor was used to imprint architectures by direct UV-assisted nanoimprint lithography (UV-NIL). The resulting Zn-containing architectures were then converted to ZnO architectures with reduced feature sizes by thermal annealing at 400 °C for 1 h. The imprinted and annealed ZnO architectures were also used as new masters for the size reduction technique. ZnO pillars of 400 nm diameter were obtained from a silicon master with pillars of 1000 nm diameter by simply repeating the size reduction technique. The photosensitivity and contrast of the Zn-containing precursor were measured as 6.5 J cm −2 and 16.5, respectively. Interesting complex ZnO patterns, with both microscale pillars and nanoscale holes, were demonstrated by the combination of dose-controlled UV exposure and a two-step UV-NIL.

  19. International Financial Reporting standard for Small and Medium-sized entities

    Directory of Open Access Journals (Sweden)

    Z Koppeschaar

    2012-12-01

    Full Text Available The International Financial Reporting Standard for Small and Medium-sized entities (IFRS for SMEs was published as a standard by the International Accounting Standards Board (IASB during July 2009. During 2007 South Africa became one of the first countries and the first country in Africa to early accept the proposed accounting standard (exposure draft of an IFRS for SMEs. The accounting standard will probably also be accepted by numerous other countries. The aim of this article is to investigate the applicability of this accounting standard. The results indicated that the IFRS for SMEs remains too comprehensive for the majority of small companies. The IFRS for SMEs does not satisfy the needs of South African users of small company financial statements, and as a result the accounting requirements should be simplified. KEYWORDS: Financial accounting; Financial reporting requirements; IFRS for SMEs; Small companies; Users of financial statements; Small company financial statements.

  20. Standardizing effect size from linear regression models with log-transformed variables for meta-analysis.

    Science.gov (United States)

    Rodríguez-Barranco, Miguel; Tobías, Aurelio; Redondo, Daniel; Molina-Portillo, Elena; Sánchez, María José

    2017-03-17

    Meta-analysis is very useful to summarize the effect of a treatment or a risk factor for a given disease. Often studies report results based on log-transformed variables in order to achieve the principal assumptions of a linear regression model. If this is the case for some, but not all studies, the effects need to be homogenized. We derived a set of formulae to transform absolute changes into relative ones, and vice versa, to allow including all results in a meta-analysis. We applied our procedure to all possible combinations of log-transformed independent or dependent variables. We also evaluated it in a simulation based on two variables either normally or asymmetrically distributed. In all the scenarios, and based on different change criteria, the effect size estimated by the derived set of formulae was equivalent to the real effect size. To avoid biased estimates of the effect, this procedure should be used with caution in the case of independent variables with asymmetric distributions that significantly differ from the normal distribution. We illustrate an application of this procedure by an application to a meta-analysis on the potential effects on neurodevelopment in children exposed to arsenic and manganese. The procedure proposed has been shown to be valid and capable of expressing the effect size of a linear regression model based on different change criteria in the variables. Homogenizing the results from different studies beforehand allows them to be combined in a meta-analysis, independently of whether the transformations had been performed on the dependent and/or independent variables.

  1. Effect of grain size on the high temperature mechanical properties of type 316LN stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. W.; Lee, Y. S.; Ryu, W. S.; Jang, J. S.; Kim, S. H.; Kim, W. G.; Cho, H. D.; Han, C. H

    2001-02-01

    Nitrogen increases the high temeprature mechanical properties and decreases grain size. The effect of nitrogen on the high temperature mechanical properties was investigated in the viewpoint of grain size. Tensile strength increases with the decrease of grain size and agrees with the Hall-Petch relationship. Effect of grain size on the low cycle fatigue life properties were investigated as measuring the fatigue life from the results which had been obtained by the constant strain rate and various strain range. There was no effect on the low cycle fatigue properties by the grain size. The time to rupture decreased with the increase of grain size. The steady state creep rate decreased to a minimum and then increased as the grain size increased. This result agrees with the result predicted from Garofalo equation. The rupture elongation at the intermediate grain size showed a minimum due to the cavity formed easily by carbide precipitates in the grain boundaries.

  2. Effective size of density-dependent two-sex populations: the effect of mating systems.

    Science.gov (United States)

    Myhre, A M; Engen, S; SAEther, B-E

    2017-08-01

    Density dependence in vital rates is a key feature affecting temporal fluctuations of natural populations. This has important implications for the rate of random genetic drift. Mating systems also greatly affect effective population sizes, but knowledge of how mating system and density regulation interact to affect random genetic drift is poor. Using theoretical models and simulations, we compare N e in short-lived, density-dependent animal populations with different mating systems. We study the impact of a fluctuating, density-dependent sex ratio and consider both a stable and a fluctuating environment. We find a negative relationship between annual N e /N and adult population size N due to density dependence, suggesting that loss of genetic variation is reduced at small densities. The magnitude of this decrease was affected by mating system and life history. A male-biased, density-dependent sex ratio reduces the rate of genetic drift compared to an equal, density-independent sex ratio, but a stochastic change towards male bias reduces the N e /N ratio. Environmental stochasticity amplifies temporal fluctuations in population size and is thus vital to consider in estimation of effective population sizes over longer time periods. Our results on the reduced loss of genetic variation at small densities, particularly in polygamous populations, indicate that density regulation may facilitate adaptive evolution at small population sizes. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  3. Surfactant effects in magnetite nanoparticles of controlled size

    International Nuclear Information System (INIS)

    Guardia, P.; Batlle-Brugal, B.; Roca, A.G.; Iglesias, O.; Morales, M.P.; Serna, C.J.; Labarta, A.; Batlle, X.

    2007-01-01

    Magnetite Fe 3 O 4 nanoparticles of controlled size within 6 and 20 nm in diameter were synthesised by thermal decomposition of an iron organic precursor in an organic medium. Particles were coated with oleic acid. For all samples studied, saturation magnetisation M s is size-independent, and reaches a value close to that expected for bulk magnetite, in contrast to results in small particle systems for which M s is usually much smaller due to surface spin disorder. The coercive field for the 6 nm particles is in agreement with coherent rotation, taking the bulk magnetocrystalline anisotropy into account. Both results suggest that the oleic acid molecules covalently bonded to the nanoparticle surface yield a strong reduction in the surface spin disorder. However, although the saturated state may be similar, the approach to saturation is different and, in particular, the high-field differential susceptibility is one order of magnitude larger than in bulk materials. The relevance of these results in biomedical applications is discussed

  4. Effects of microparticle size and Fc density on macrophage phagocytosis.

    Directory of Open Access Journals (Sweden)

    Patricia Pacheco

    Full Text Available Controlled induction of phagocytosis in macrophages offers the ability to therapeutically regulate the immune system as well as improve delivery of chemicals or biologicals for immune processing. Maximizing particle uptake by macrophages through Fc receptor-mediated phagocytosis could lead to new delivery mechanisms in drug or vaccine development. Fc ligand density and particle size were examined independently and in combination in order to optimize and tune the phagocytosis of opsonized microparticles. We show the internalization efficiency of small polystyrene particles (0.5 µm to 2 µm is significantly affected by changes in Fc ligand density, while particles greater than 2 µm show little correlation between internalization and Fc density. We found that while macrophages can efficiently phagocytose a large number of smaller particles, the total volume of phagocytosed particles is maximized through the non-specific uptake of larger microparticles. Therefore, larger microparticles may be more efficient at delivering a greater therapeutic payload to macrophages, but smaller opsonized microparticles can deliver bio-active substances to a greater percentage of the macrophage population. This study is the first to treat as independent variables the physical and biological properties of Fc density and microparticle size that initiate macrophage phagocytosis. Defining the physical and biological parameters that affect phagocytosis efficiency will lead to improved methods of microparticle delivery to macrophages.

  5. What about N? A methodological study of sample-size reporting in focus group studies.

    Science.gov (United States)

    Carlsen, Benedicte; Glenton, Claire

    2011-03-11

    Focus group studies are increasingly published in health related journals, but we know little about how researchers use this method, particularly how they determine the number of focus groups to conduct. The methodological literature commonly advises researchers to follow principles of data saturation, although practical advise on how to do this is lacking. Our objectives were firstly, to describe the current status of sample size in focus group studies reported in health journals. Secondly, to assess whether and how researchers explain the number of focus groups they carry out. We searched PubMed for studies that had used focus groups and that had been published in open access journals during 2008, and extracted data on the number of focus groups and on any explanation authors gave for this number. We also did a qualitative assessment of the papers with regard to how number of groups was explained and discussed. We identified 220 papers published in 117 journals. In these papers insufficient reporting of sample sizes was common. The number of focus groups conducted varied greatly (mean 8.4, median 5, range 1 to 96). Thirty seven (17%) studies attempted to explain the number of groups. Six studies referred to rules of thumb in the literature, three stated that they were unable to organize more groups for practical reasons, while 28 studies stated that they had reached a point of saturation. Among those stating that they had reached a point of saturation, several appeared not to have followed principles from grounded theory where data collection and analysis is an iterative process until saturation is reached. Studies with high numbers of focus groups did not offer explanations for number of groups. Too much data as a study weakness was not an issue discussed in any of the reviewed papers. Based on these findings we suggest that journals adopt more stringent requirements for focus group method reporting. The often poor and inconsistent reporting seen in these

  6. What about N? A methodological study of sample-size reporting in focus group studies

    Directory of Open Access Journals (Sweden)

    Glenton Claire

    2011-03-01

    Full Text Available Abstract Background Focus group studies are increasingly published in health related journals, but we know little about how researchers use this method, particularly how they determine the number of focus groups to conduct. The methodological literature commonly advises researchers to follow principles of data saturation, although practical advise on how to do this is lacking. Our objectives were firstly, to describe the current status of sample size in focus group studies reported in health journals. Secondly, to assess whether and how researchers explain the number of focus groups they carry out. Methods We searched PubMed for studies that had used focus groups and that had been published in open access journals during 2008, and extracted data on the number of focus groups and on any explanation authors gave for this number. We also did a qualitative assessment of the papers with regard to how number of groups was explained and discussed. Results We identified 220 papers published in 117 journals. In these papers insufficient reporting of sample sizes was common. The number of focus groups conducted varied greatly (mean 8.4, median 5, range 1 to 96. Thirty seven (17% studies attempted to explain the number of groups. Six studies referred to rules of thumb in the literature, three stated that they were unable to organize more groups for practical reasons, while 28 studies stated that they had reached a point of saturation. Among those stating that they had reached a point of saturation, several appeared not to have followed principles from grounded theory where data collection and analysis is an iterative process until saturation is reached. Studies with high numbers of focus groups did not offer explanations for number of groups. Too much data as a study weakness was not an issue discussed in any of the reviewed papers. Conclusions Based on these findings we suggest that journals adopt more stringent requirements for focus group method

  7. Nature of size effects in compact models of field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Torkhov, N. A., E-mail: trkf@mail.ru [Tomsk State University, Tomsk 634050 (Russian Federation); Scientific-Research Institute of Semiconductor Devices, Tomsk 634050 (Russian Federation); Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Babak, L. I.; Kokolov, A. A.; Salnikov, A. S.; Dobush, I. M. [Tomsk State University of Control Systems and Radioelectronics, Tomsk 634050 (Russian Federation); Novikov, V. A., E-mail: novikovvadim@mail.ru; Ivonin, I. V. [Tomsk State University, Tomsk 634050 (Russian Federation)

    2016-03-07

    Investigations have shown that in the local approximation (for sizes L < 100 μm), AlGaN/GaN high electron mobility transistor (HEMT) structures satisfy to all properties of chaotic systems and can be described in the language of fractal geometry of fractional dimensions. For such objects, values of their electrophysical characteristics depend on the linear sizes of the examined regions, which explain the presence of the so-called size effects—dependences of the electrophysical and instrumental characteristics on the linear sizes of the active elements of semiconductor devices. In the present work, a relationship has been established for the linear model parameters of the equivalent circuit elements of internal transistors with fractal geometry of the heteroepitaxial structure manifested through a dependence of its relative electrophysical characteristics on the linear sizes of the examined surface areas. For the HEMTs, this implies dependences of their relative static (A/mm, mA/V/mm, Ω/mm, etc.) and microwave characteristics (W/mm) on the width d of the sink-source channel and on the number of sections n that leads to a nonlinear dependence of the retrieved parameter values of equivalent circuit elements of linear internal transistor models on n and d. Thus, it has been demonstrated that the size effects in semiconductors determined by the fractal geometry must be taken into account when investigating the properties of semiconductor objects on the levels less than the local approximation limit and designing and manufacturing field effect transistors. In general, the suggested approach allows a complex of problems to be solved on designing, optimizing, and retrieving the parameters of equivalent circuits of linear and nonlinear models of not only field effect transistors but also any arbitrary semiconductor devices with nonlinear instrumental characteristics.

  8. Effects of oral administration of titanium dioxide fine-sized particles on plasma glucose in mice.

    Science.gov (United States)

    Gu, Ning; Hu, Hailong; Guo, Qian; Jin, Sanli; Wang, Changlin; Oh, Yuri; Feng, Yujie; Wu, Qiong

    2015-12-01

    Titanium dioxide (TiO2) is an authorized additive used as a food colorant, is composed of nano-sized particles (NP) and fine-sized particles (FP). Previous study reported that oral administration of TiO2 NPs triggers an increase in plasma glucose of mice. However, no previous studies have focused on toxic effects of TiO2 FPs on plasma glucose homeostasis following oral administration. In the current study, mice were orally administered TiO2 FPs greater than 100 nm in size (64 mg/kg body weight per day), and effects on plasma glucose levels examined. Our results showed that titanium levels was not changed in mouse blood, livers and pancreases after mice were orally administered TiO2 FPs. Biochemical analyzes showed that plasma glucose and ROS levels were not affected by TiO2 FPs. Histopathological results showed that TiO2 FPs did not induce pathology changes in organs, especially plasma glucose homeostasis regulation organs, such as pancreas and liver. Western blotting showed that oral administration of TiO2 FPs did not induce insulin resistance (IR) in mouse liver. These results showed that, TiO2 FPs cannot be absorbed via oral administration and affect plasma glucose levels in mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Pen size and parity effects on maternal behaviour of Small-Tail Han sheep.

    Science.gov (United States)

    Lv, S-J; Yang, Y; Dwyer, C M; Li, F-K

    2015-07-01

    The aim of this experiment was to study the effects of pen size and parity on maternal behaviour of twin-bearing Small-Tail Han ewes. A total of 24 ewes were allocated to a 2×2 design (six per pen), with parity (primiparous or multiparous) and pen size (large: 6.0×3.0 m; small: 6.0×1.5 m) as main effects at Linyi University, Shandong Province, China. Behaviour was observed from after parturition until weaning. All ewes were observed for 6 h every 5 days from 0700 to1000 h and from 1400 to 1700 h. Continuous focal animal sampling was used to quantify the duration of maternal behaviours: sucking, grooming and following as well as the frequency of udder accepting, udder refusing and low-pitched bleating. Oestradiol and cortisol concentrations in the faeces (collected in the morning every 5 days) were detected using EIA kits. All lambs were weighed 24 h after parturition and again at weaning at 35 days of age. The small pen size significantly reduced following (Pbehaviour in sheep during lactation. The study is also the first to report on the maternal behaviour of Chinese native sheep breeds (Small-Tail Han sheep), with implications for the production of sheep in China.

  10. Statistical properties of four effect-size measures for mediation models.

    Science.gov (United States)

    Miočević, Milica; O'Rourke, Holly P; MacKinnon, David P; Brown, Hendricks C

    2018-02-01

    This project examined the performance of classical and Bayesian estimators of four effect size measures for the indirect effect in a single-mediator model and a two-mediator model. Compared to the proportion and ratio mediation effect sizes, standardized mediation effect-size measures were relatively unbiased and efficient in the single-mediator model and the two-mediator model. Percentile and bias-corrected bootstrap interval estimates of ab/s Y , and ab(s X )/s Y in the single-mediator model outperformed interval estimates of the proportion and ratio effect sizes in terms of power, Type I error rate, coverage, imbalance, and interval width. For the two-mediator model, standardized effect-size measures were superior to the proportion and ratio effect-size measures. Furthermore, it was found that Bayesian point and interval summaries of posterior distributions of standardized effect-size measures reduced excessive relative bias for certain parameter combinations. The standardized effect-size measures are the best effect-size measures for quantifying mediated effects.

  11. Food and disturbance effects on Arctic benthic biomass and production size spectra

    Science.gov (United States)

    Górska, Barbara; Włodarska-Kowalczuk, Maria

    2017-03-01

    Body size is a fundamental biological unit that is closely coupled to key ecological properties and processes. At the community level, changes in size distributions may influence energy transfer pathways in benthic food webs and ecosystem carbon cycling; nevertheless they remain poorly explored in benthic systems, particularly in the polar regions. Here, we present the first assessment of the patterns of benthic biomass size spectra in Arctic coastal sediments and explore the effects of glacial disturbance and food availability on the partitioning of biomass and secondary productivity among size-defined components of benthic communities. The samples were collected in two Arctic fjords off west Spitsbergen (76 and 79°N), at 6 stations that represent three regimes of varying food availability (indicated by chlorophyll a concentration in the sediments) and glacial sedimentation disturbance intensity (indicated by sediment accumulation rates). The organisms were measured using image analysis to assess the biovolume, biomass and the annual production of each individual. The shape of benthic biomass size spectra at most stations was bimodal, with the location of a trough and peaks similar to those previously reported in lower latitudes. In undisturbed sediments macrofauna comprised 89% of the total benthic biomass and 56% of the total production. The lower availability of food resources seemed to suppress the biomass and secondary production across the whole size spectra (a 6-fold decrease in biomass and a 4-fold decrease in production in total) rather than reshape the spectrum. At locations where poor nutritional conditions were coupled with disturbance, the biomass was strongly reduced in selected macrofaunal size classes (class 10 and 11), while meiofaunal biomass and production were much higher, most likely due to a release from macrofaunal predation and competition pressure. As a result, the partitioning of benthic biomass and production shifted towards meiofauna

  12. The Effect of Trade Openness and Income on the Size of a Government

    Directory of Open Access Journals (Sweden)

    Taner TURAN

    2016-02-01

    Full Text Available This paper examines the effect of trade openness and per capita GDP on the size of government for Turkey and South Korea by means of ARDL approach to co-integration. We use different proxies to measure the size of government because not all measures of government size are appropriate to be employed in the estimates. Among the three (four different measures of government size of Korea (Turkey, only one for each country has a co-integrating relationship with openness and per capita GDP. Long run coeffi cients suggest that per capita GDP has a positive and signifi cant effect on the government sizes for Turkey and Korea, implying the validity of the Wagner’s law. However, while openness has a negative effect on government size for Turkey, it has a positive effect for Korea. Our results clearly highlight the importance of choosing an appropriate proxy for government size to reach robust and consistent results.

  13. Effect of Particle Size and Operating Conditions on Pt3Co PEMFC Cathode Catalyst Durability

    Directory of Open Access Journals (Sweden)

    Mallika Gummalla

    2015-05-01

    Full Text Available The initial performance and decay trends of polymer electrolyte membrane fuel cells (PEMFC cathodes with Pt3Co catalysts of three mean particle sizes (4.9 nm, 8.1 nm, and 14.8 nm with identical Pt loadings are compared. Even though the cathode based on 4.9 nm catalyst exhibited the highest initial electrochemical surface area (ECA and mass activity, the cathode based on 8.1 nm catalyst showed better initial performance at high currents. Owing to the low mass activity of the large particles, the initial performance of the 14.8 nm Pt3Co-based electrode was the lowest. The performance decay rate of the electrodes with the smallest Pt3Co particle size was the highest and that of the largest Pt3Co particle size was lowest. Interestingly, with increasing number of decay cycles (0.6 to 1.0 V, 50 mV/s, the relative improvement in performance of the cathode based on 8.1 nm Pt3Co over the 4.9 nm Pt3Co increased, owing to better stability of the 8.1 nm catalyst. The electron microprobe analysis (EMPA of the decayed membrane-electrode assembly (MEA showed that the amount of Co in the membrane was lower for the larger particles, and the platinum loss into the membrane also decreased with increasing particle size. This suggests that the higher initial performance at high currents with 8.1 nm Pt3Co could be due to lower contamination of the ionomer in the electrode. Furthermore, lower loss of Co from the catalyst with increased particle size could be one of the factors contributing to the stability of ECA and mass activity of electrodes with larger cathode catalyst particles. To delineate the impact of particle size and alloy effects, these results are compared with prior work from our research group on size effects of pure platinum catalysts. The impact of PEMFC operating conditions, including upper potential, relative humidity, and temperature on the alloy catalyst decay trends, along with the EMPA analysis of the decayed MEAs, are reported.

  14. Effects of Aperture Size on Q factor and Shielding Effectiveness of a Cubic Resonator

    Directory of Open Access Journals (Sweden)

    S. Parr

    2017-09-01

    Full Text Available The EMC properties of a cubic metallic shield are highly affected by its resonances. At the resonant frequencies, the shielding effectiveness (SE collapses, which results in high field strengths inside the cavity. This can cause failure or even breakdown of electronic devices inside the shield. The resonant behaviour is mainly determined by the quality or Q factor of the shield. In this paper, the effects of the aperture size on the Q factor and the SE of an electrically large, cubic shield are analysed. At first, a method is developed in order to determine the Q factor based on the resonance behaviour of the shield in time domain. Only the first resonance of the shield is considered therefore. The results are evaluated for different aperture diameters and compared with theory for the Q factor. The dominant coupling mechanism of electromagnetic energy into the shield is thus identified. Then the effect of aperture size on the SE is analysed. The excitation of resonances is very probable if the interfering signal is an ultrawideband (UWB pulse, which constitutes a typical intentional electromagnetic interference (IEMI scenario. Therefore, the relation between aperture size and SE is analysed using the theory of the transient SE for a broadband signal with a constant spectral density distribution. The results show, that a worst case aperture size exists, where the SE has its minimum.

  15. New Evidence of the Causal Effect of Family Size on Child Quality in a Developing Country

    Science.gov (United States)

    Ponczek, Vladimir; Souza, Andre Portela

    2012-01-01

    This paper presents new evidence of the causal effect of family size on child quality in a developing-country context. We estimate the impact of family size on child labor and educational outcomes among Brazilian children and young adults by exploring the exogenous variation of family size driven by the presence of twins in the family. Using the…

  16. Grain-size effects on thermal properties of BaTiO3 ceramics

    Indian Academy of Sciences (India)

    Administrator

    decreasing grain size. Furthermore, the Curie temperature shifts to lower temperature with decreasing grain size. Keywords. Nanocrystalline ceramics; thermal properties; size effect. 1. Introduction. BaTiO3 has been widely used in the electronic industry for its high dielectric constant and low losses above room temperature ...

  17. Size and field effect on mesoscopic spin glass

    Energy Technology Data Exchange (ETDEWEB)

    Komatsu, K. [Department of Applied Physics and Physico-Infomatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan)]. E-mail: komatsu@az.appi.keio.ac.jp; Maki, H. [Department of Applied Physics and Physico-Infomatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Taniyama, T. [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Sato, T. [Department of Applied Physics and Physico-Infomatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan)

    2007-03-15

    Spin glass particles were prepared as the mesoscopic system in order to examine the space scale of spin glass domain (droplet). The peak temperature T {sub peak} in the temperature-dependent magnetization is systematically reduced with decreasing average particle size. This is due to the imitation of droplet growth to the particle diameter. The magnetic field H also decreases T {sub peak}, which is caused by the reduction of the barrier height by Zeeman energy. However, there appears different tendency in the relation between H and T {sub peak} below 100 Oe. This indicates the existence of crossover between the two regimes in which the free energy and Zeeman energy govern the droplet excitation.

  18. Uncertainties in effective dose estimates of adult CT head scans: The effect of head size

    International Nuclear Information System (INIS)

    Gregory, Kent J.; Bibbo, Giovanni; Pattison, John E.

    2009-01-01

    Purpose: This study is an extension of a previous study where the uncertainties in effective dose estimates from adult CT head scans were calculated using four CT effective dose estimation methods, three of which were computer programs (CT-EXPO, CTDOSIMETRY, and IMPACTDOSE) and one that involved the dose length product (DLP). However, that study did not include the uncertainty contribution due to variations in head sizes. Methods: The uncertainties due to head size variations were estimated by first using the computer program data to calculate doses to small and large heads. These doses were then compared with doses calculated for the phantom heads used by the computer programs. An uncertainty was then assigned based on the difference between the small and large head doses and the doses of the phantom heads. Results: The uncertainties due to head size variations alone were found to be between 4% and 26% depending on the method used and the patient gender. When these uncertainties were included with the results of the previous study, the overall uncertainties in effective dose estimates (stated at the 95% confidence interval) were 20%-31% (CT-EXPO), 15%-30% (CTDOSIMETRY), 20%-36% (IMPACTDOSE), and 31%-40% (DLP). Conclusions: For the computer programs, the lower overall uncertainties were still achieved when measured values of CT dose index were used rather than tabulated values. For DLP dose estimates, head size variations made the largest (for males) and second largest (for females) contributions to effective dose uncertainty. An improvement in the uncertainty of the DLP method dose estimates will be achieved if head size variation can be taken into account.

  19. Uncertainties in effective dose estimates of adult CT head scans: The effect of head size

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, Kent J.; Bibbo, Giovanni; Pattison, John E. [Department of Medical Physics, Royal Adelaide Hospital, Adelaide, South Australia 5000 (Australia) and School of Electrical and Information Engineering (Applied Physics), University of South Australia, Mawson Lakes, South Australia 5095 (Australia); Division of Medical Imaging, Women' s and Children' s Hospital, North Adelaide, South Australia 5006 (Australia) and School of Electrical and Information Engineering (Applied Physics), University of South Australia, Mawson Lakes, South Australia 5095 (Australia); School of Electrical and Information Engineering (Applied Physics), University of South Australia, Mawson Lakes, South Australia 5095 (Australia)

    2009-09-15

    Purpose: This study is an extension of a previous study where the uncertainties in effective dose estimates from adult CT head scans were calculated using four CT effective dose estimation methods, three of which were computer programs (CT-EXPO, CTDOSIMETRY, and IMPACTDOSE) and one that involved the dose length product (DLP). However, that study did not include the uncertainty contribution due to variations in head sizes. Methods: The uncertainties due to head size variations were estimated by first using the computer program data to calculate doses to small and large heads. These doses were then compared with doses calculated for the phantom heads used by the computer programs. An uncertainty was then assigned based on the difference between the small and large head doses and the doses of the phantom heads. Results: The uncertainties due to head size variations alone were found to be between 4% and 26% depending on the method used and the patient gender. When these uncertainties were included with the results of the previous study, the overall uncertainties in effective dose estimates (stated at the 95% confidence interval) were 20%-31% (CT-EXPO), 15%-30% (CTDOSIMETRY), 20%-36% (IMPACTDOSE), and 31%-40% (DLP). Conclusions: For the computer programs, the lower overall uncertainties were still achieved when measured values of CT dose index were used rather than tabulated values. For DLP dose estimates, head size variations made the largest (for males) and second largest (for females) contributions to effective dose uncertainty. An improvement in the uncertainty of the DLP method dose estimates will be achieved if head size variation can be taken into account.

  20. The effect of changes in humidity on the size of submicron aerosols

    International Nuclear Information System (INIS)

    Phillips, C.R.; Khan, A.

    1987-06-01

    The effect of humidity on inhaled aerosols in the respiratory tract is to cause an increase in particle size of up to several times if the aerosol particle is hygroscopic. The presence of ionizing radiation and air ions (for example, from uranium and radon/thoron) increases the tendency of water vapour to nucleate. The desposition of particles in the lung is enhanced by high charge density (>10 charges/particle). Radon has been reported to play an important role in the formation of sulphate and nitrate particles in the atmosphere. A detailed overview of the effect of humidity on aerosols is presented in the present work. Results of experimental measurements made on NaCl (hygroscopic) and kerosene combustion (hydrophobic) aerosols under ambient and humid conditions are reported. Initial aerosol conditions were 20 degrees C and 35% R.H. Final aerosol conditions were maintained at 37 degrees C and 100% R.H. in order to simulate the conditions inside the respiratory tract. An average growth factor of 1.9 ± 0.4 (standard deviation) was observed for the NaCl aerosol and 1.3 ± 0.2 (standard deviation) for the kerosene aerosol. For the activity size distribution, however, the NaCl aerosols were observed to grow by an average factor of only 1.2 ± 0.1 (standard deviation) whereas the kerosene aerosols grew by a factor of 1.3 ± 0.2 (standard deviation)

  1. Evaluation of the Company Size Effect on Latin American Stock Markets

    Directory of Open Access Journals (Sweden)

    Juan Benjamín Duarte Duarte

    2013-11-01

    Full Text Available This paper assesses the existence of the size effect on the most important stock markets in Latin America (Argentina, Brazil, Chile, Colombia, Mexico and Peru for the period between 2002 and 2012, using the cross-section contrast methodology of the size effect in the CAPM context. Results show that there is reversed effect in some of the Latin American markets.

  2. Effect-Size Measures and Meta-Analytic Thinking in Counseling Psychology Research

    Science.gov (United States)

    Henson, Robin K.

    2006-01-01

    Effect sizes are critical to result interpretation and synthesis across studies. Although statistical significance testing has historically dominated the determination of result importance, modern views emphasize the role of effect sizes and confidence intervals. This article accessibly discusses how to calculate and interpret the effect sizes…

  3. Secular trends in reported portion size of food and beverages consumed by Irish adults.

    Science.gov (United States)

    O'Brien, Sinead A; Livingstone, M Barbara E; McNulty, Breige A; Lyons, Jacqueline; Walton, Janette; Flynn, Albert; Segurado, Ricardo; Dean, Moira; Spence, Michelle; McCaffrey, Tracy A; Pourshahidi, L Kirsty; Nugent, Anne P; Gibney, Eileen R

    2015-04-14

    The present analysis aimed to investigate the changes in the reported portion sizes (PS) of foods and beverages commonly consumed by Irish adults (18-64 years) from the North South Ireland Food Consumption Survey (NSIFCS) (1997-2001) and the National Adult Nutrition Survey (NANS) (2008-10). Food PS, which are defined as the weight of food (g) consumed per eating occasion, were calculated for comparable foods and beverages in two nationally representative cross-sectional Irish food consumption surveys and were published in NSIFCS and NANS. Repeated measure mixed model analysis compared reported food PS at the total population level as well as subdivided by sex, age, BMI and social class. A total of thirteen commonly consumed foods were examined. The analysis demonstrated that PS significantly increased for five foods ('white sliced bread', 'brown/wholemeal breads', 'all meat, cooked', 'poultry, roasted' and 'milk'), significantly decreased for three ('potatoes', 'chips/wedges' and 'ham, sliced') and did not significantly change for five foods ('processed potato products', 'bacon/ham', 'cheese', 'yogurt' and 'butter/spreads') between the NSIFCS and the NANS. The present study demonstrates that there was considerable variation in the trends in reported food PS over this period.

  4. Effects of Sample Size and Dimensionality on the Performance of Four Algorithms for Inference of Association Networks in Metabonomics

    NARCIS (Netherlands)

    Suarez Diez, M.; Saccenti, E.

    2015-01-01

    We investigated the effect of sample size and dimensionality on the performance of four algorithms (ARACNE, CLR, CORR, and PCLRC) when they are used for the inference of metabolite association networks. We report that as many as 100-400 samples may be necessary to obtain stable network estimations,

  5. The effective size of the Icelandic population and the prospects for LD mapping: inference from unphased microsatellite markers

    DEFF Research Database (Denmark)

    Bataillon, Thomas; Mailund, Thomas; Thorlacius, Steinunn

    2006-01-01

    on scaled recombination rates from patterns of LD. Patterns of LD in Iceland suggest a genome-wide scaled recombination rate of ρ* = 200 [130–330] per cM which is equivalent to a long term effective population size of ~5000 in the range of estimates recently reported in three populations using extensive...

  6. Interim design status and operational report for semiremote handling fixtures: size reduction system

    International Nuclear Information System (INIS)

    Ballard, A.S.

    1977-02-01

    Crushing of HTGR fuel elements is accomplished by a three-stage crushing system consisting of two overhead eccentric jaw crushers, a double-roll crusher, and an oversize reduction system to ensure complete reduction to the desired size. The crushing system is mounted in a special framework which enables gravity flow, eliminates material transport, and minimizes material holdup. The system has been designated UNIFRAME because of the integrated nature of the equipment. This report addresses the demonstration of semiremote maintenance of the crusher in a nonradioactive environment. Although the crusher maintenance system has some remote handling capability inherent in its design, the scope of this initial program is limited to the handling of selected components and allows for manual assistance in certain circumstances. This mode of operation is designated semiremote maintenance and is intended as an effort to gather experience

  7. Effect of effective grain size on Charpy impact properties of high-strength bainitic steels

    International Nuclear Information System (INIS)

    Shin, Sang Yong; Han, Seung Youb; Lee, Sung Hak; Hwang, Byoung Chul; Lee, Chang Gil

    2008-01-01

    This study is concerned with the effect of Cu and B addition on microstructure and mechanical properties of high-strength bainitic steels. Six kinds of steels were fabricated by varying alloying elements and hot-rolling conditions, and their microstructures and tensile and Charpy impact properties were investigated. Their effective grain sizes were also characterized by the electron back-scatter diffraction analysis. The tensile test results indicated that the B- or Cu-containing steels had the higher yield and tensile strengths than the B- or Cu-free steels because their volume fractions of bainitic ferrite and martensite were quite high. The B- or Cu-free steels had the higher upper shelf energy than the B- or Cu-containing steels because of their higher volume fraction of granular bainite. In the steel containing 10 ppm B without Cu, the best combination of high strengths, high upper shelf energy, and low energy transition temperature could be obtained by the decrease in the overall effective grain size due to the presence of bainitic ferrite having smaller effective grain size

  8. Effect of particle size on thermal decomposition of alkali metal picrates

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rui; Zhang, Tonglai, E-mail: ztlbit@bit.edu.cn; Yang, Li; Zhou, Zunning

    2014-05-01

    Graphical abstract: The smaller-sized picrate has greater gas emission than do its larger counterpart. The small size effect reduces the thermal decomposition activation energy, accelerates the reaction rate, and promotes the reaction activity. - Highlights: • Picrates were prepared into three micron sizes by microemulsion synthesis. • Thermal decomposition kinetics and thermodynamics were studied by DPTA and DSC. • Smaller-sized picrate has higher activity and faster reaction rate. • Particle size effect on thermal decomposition kinetics and thermodynamics was revealed. - Abstract: Three alkali metal picrates, KPA, RbPA and CsPA, were prepared into three micron sizes by microemulsion synthesis, and their thermal decomposition behaviors were investigated by DPTA at different temperatures and by DSC at different heating rates. The smaller-sized picrate has greater gas emission and smaller kinetic and thermodynamic parameters than do its larger counterpart. It can be attributed to the decreasing particle size which leads to the high surface energy, the fast mass and heat transfer, and the increasing active sites on the reaction interface. The small size effect and surface effect cause the autocatalysis which reduces the activation energy and promotes the reaction activity. The particle size does not affect the reaction mechanism. However, the picrates with different central alkali metals exhibit different reaction mechanisms even though they are of the same size. This is because the central metal determines the bond energy and consequently affects the stability of picrate.

  9. Effect of particle size on thermal decomposition of alkali metal picrates

    International Nuclear Information System (INIS)

    Liu, Rui; Zhang, Tonglai; Yang, Li; Zhou, Zunning

    2014-01-01

    Graphical abstract: The smaller-sized picrate has greater gas emission than do its larger counterpart. The small size effect reduces the thermal decomposition activation energy, accelerates the reaction rate, and promotes the reaction activity. - Highlights: • Picrates were prepared into three micron sizes by microemulsion synthesis. • Thermal decomposition kinetics and thermodynamics were studied by DPTA and DSC. • Smaller-sized picrate has higher activity and faster reaction rate. • Particle size effect on thermal decomposition kinetics and thermodynamics was revealed. - Abstract: Three alkali metal picrates, KPA, RbPA and CsPA, were prepared into three micron sizes by microemulsion synthesis, and their thermal decomposition behaviors were investigated by DPTA at different temperatures and by DSC at different heating rates. The smaller-sized picrate has greater gas emission and smaller kinetic and thermodynamic parameters than do its larger counterpart. It can be attributed to the decreasing particle size which leads to the high surface energy, the fast mass and heat transfer, and the increasing active sites on the reaction interface. The small size effect and surface effect cause the autocatalysis which reduces the activation energy and promotes the reaction activity. The particle size does not affect the reaction mechanism. However, the picrates with different central alkali metals exhibit different reaction mechanisms even though they are of the same size. This is because the central metal determines the bond energy and consequently affects the stability of picrate

  10. Effect Size in Efficacy Trials of Women With Decreased Sexual Desire.

    Science.gov (United States)

    Pyke, Robert E; Clayton, Anita H

    2018-03-22

    Regarding hypoactive sexual desire disorder (HSDD) in women, some reviewers judge the effect size small for medications vs placebo, but substantial for cognitive behavior therapy (CBT) or mindfulness meditation training (MMT) vs wait list. However, we lack comparisons of the effect sizes for the active intervention itself, for the control treatment, and for the differential between the two. For efficacy trials of HSDD in women, compare effect sizes for medications (testosterone/testosterone transdermal system, flibanserin, and bremelanotide) and placebo vs effect sizes for psychotherapy and wait-list control. We conducted a literature search for mean changes and SD on main measures of sexual desire and associated distress in trials of medications, CBT, or MMT. Effect size was used as it measures the magnitude of the intervention without confounding by sample size. Cohen d was used to determine effect sizes. For medications, mean (SD) effect size was 1.0 (0.34); for CBT and MMT, 1.0 (0.36); for placebo, 0.55 (0.16); and for wait list, 0.05 (0.26). Recommendations of psychotherapy over medication for treatment of HSDD are premature and not supported by data on effect sizes. Active participation in treatment conveys considerable non-specific benefits. Caregivers should attend to biological and psychosocial elements, and patient preference, to optimize response. Few clinical trials of psychotherapies were substantial in size or utilized adequate control paradigms. Medications and psychotherapies had similar, large effect sizes. Effect size of placebo was moderate. Effect size of wait-list control was very small, about one quarter that of placebo. Thus, a substantial non-specific therapeutic effect is associated with receiving placebo plus active care and evaluation. The difference in effect size between placebo and wait-list controls distorts the value of the subtraction of effect of the control paradigms to estimate intervention effectiveness. Pyke RE, Clayton AH

  11. Size effects in electrical behavior of high-Tc thin-film bridges

    International Nuclear Information System (INIS)

    Afanasyev, A.S.; Gubankov, V.N.; Divin, Y.Y.

    1991-01-01

    This paper reports on the size effects in electrical characteristics of polycrystalline YBa 2 Cu 3 O 7-x thin-film bridges studied in the temperature range 4-300K. It is shown, that at T > T c the decrease of bridge widths w from 200 to 10 μm leads to the increase of resistance R in several times and to the change in R □ (T) behavior □ from metallic type to activation type. At □ T approx-lt T c the R □ (w) values exponentially increased when the width w was decreased under some definite size L. At T c the index I c (T) ∼ (T - T) α changed from 3 to 1 if bridge width was decreased. Experimental data are discussed within the model, which takes into account large-scale percolation processes in the system of different intergrain Josephson junctions, where characteristic length L 0 of critical subnetwork is much larger than the grain size

  12. Metastable structures and size effects in small group dynamics.

    Science.gov (United States)

    Lauro Grotto, Rosapia; Guazzini, Andrea; Bagnoli, Franco

    2014-01-01

    In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological states that are characterized by a series of features: (1) they emerge as a consequence of the natural tendency of (both conscious and unconscious) emotions to combine into structured group patterns; (2) they have a certain degree of stability in time; (3) they tend to alternate so that the dissolution of one is rapidly followed by the emergence of another; (4) they can be described in qualitative terms according to the nature of the emotional mix that dominates the state, in structural terms by a kind of typical "leadership" pattern, and in "cognitive" terms by a set of implicit expectations that are helpful in explaining the group behavior (i.e., the group behaves "as if" it was assuming that). Here we adopt a formal approach derived from Socio-physics in order to explore some of the structural and dynamic properties of this small group dynamics. We will described data from an analytic DS model simulating small group interactions of agents endowed with a very simplified emotional and cognitive dynamic in order to assess the following main points: (1) are metastable collective states allowed to emerge in the model and if so, under which conditions in the parameter space? (2) can these states be differentiated in structural terms? (3) to what extent are the emergent dynamic features of the systems dependent of the system size? We will finally discuss possible future applications of the quantitative descriptions of the interaction structure in the small group clinical setting.

  13. Metastable structures and size effects in small group dynamics

    Directory of Open Access Journals (Sweden)

    Rosapia eLauro Grotto

    2014-07-01

    Full Text Available In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological states that are characterized by a series of features: 1 they emerge as a consequence of the natural tendency of (both conscious and unconscious emotions to combine into structured group patterns; 2 they have a certain degree of stability in time; 3 they tend to alternate so that the dissolution of one is rapidly followed by the emergence of another; 4 they can be described in qualitative terms according to the nature of the emotional mix that dominates the state, in structural terms by a kind of typical 'leadership’ pattern, and in 'cognitive’ terms by a set of implicit expectations that are helpful in explaining the group behavior (i.e. the group behaves 'as if’ it was assuming that…. Here we adopt a formal approach derived from Socio-physics in order to explore some of the structural and dynamic properties of this small group dynamics. We will described data from an analytic DS model simulating small group interactions of agents endowed with a very simplified emotional and cognitive dynamic in order to assess the following main points: 1 are metastable collective states allowed to emerge in the model and if so, under which conditions in the parameter space? 3 can these states be differentiated in structural terms? 3 to what extent are the emergent dynamic features of the systems dependent of the system size? We will finally discuss possible future applications of the quantitative descriptions of the interaction structure in the small group clinical

  14. Rolling induced size effects in elastic–viscoplastic sheet metals

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2015-01-01

    sheet rolling, where a non-homogeneous material deformation takes place between the rollers. Large strain gradients develop where the rollers first come in contact with the sheet, and a higher order plasticity model is employed to illustrate their influence at small scales. The study reveals...... presented revolves around the rolling induced effect of visco-plasticity (ranging hot and cold rolling) in combination with strain gradient hardening – including both dissipative and energetic contributions. To bring out first order effects on rolling at small scale, the modeling efforts are limited to flat...

  15. Effects of fuel particle size distributions on neutron transport in stochastic media

    International Nuclear Information System (INIS)

    Liang, Chao; Pavlou, Andrew T.; Ji, Wei

    2014-01-01

    Highlights: • Effects of fuel particle size distributions on neutron transport are evaluated. • Neutron channeling is identified as the fundamental reason for the effects. • The effects are noticeable at low packing and low optical thickness systems. • Unit cells of realistic reactor designs are studied for different size particles. • Fuel particle size distribution effects are not negligible in realistic designs. - Abstract: This paper presents a study of the fuel particle size distribution effects on neutron transport in three-dimensional stochastic media. Particle fuel is used in gas-cooled nuclear reactor designs and innovative light water reactor designs loaded with accident tolerant fuel. Due to the design requirements and fuel fabrication limits, the size of fuel particles may not be perfectly constant but instead follows a certain distribution. This brings a fundamental question to the radiation transport computation community: how does the fuel particle size distribution affect the neutron transport in particle fuel systems? To answer this question, size distribution effects and their physical interpretations are investigated by performing a series of neutron transport simulations at different fuel particle size distributions. An eigenvalue problem is simulated in a cylindrical container consisting of fissile fuel particles with five different size distributions: constant, uniform, power, exponential and Gaussian. A total of 15 parametric cases are constructed by altering the fissile particle volume packing fraction and its optical thickness, but keeping the mean chord length of the spherical fuel particle the same at different size distributions. The tallied effective multiplication factor (k eff ) and the spatial distribution of fission power density along axial and radial directions are compared between different size distributions. At low packing fraction and low optical thickness, the size distribution shows a noticeable effect on neutron

  16. Minimizing infarct size. Annual scientific report, 1 Jul 1975--15 Apr 1976

    International Nuclear Information System (INIS)

    Braunwald, E.

    1976-01-01

    Several goals were achieved during this period of 9 months, both in the experimental laboratory and in patients with acute myocardial infarction. (1) A study of the effects of aprotinin administration on myocardial ischemic injury, subsequent necrosis and collateral blood flow following acute coronary artery occlusion was carried out to completion. (2) A study of the effect of cobra venom factor on myocardial necrosis was completed and the factors responsible for its action were examined. (3) A comparison was made of the effects of nitroglycerin and nitroprusside on ischemic injury and regional myocardial blood flow in patients with acute myocardial infarction and in dogs with coronary occlusions. (4) A method of direct measurement of infarct size in the rat was developed. It consists of occlusion of the main left coronary artery and the histologic quantification of the infarct at 48 hours and 3 weeks later by serial histologic sections or alternatively by measuring total left ventricular myocardial creative phosphokinase activity. (5) New electrocardiographic methods have been developed in order to evaluate atraumatically the extent of myocardial infarction in patients. (6) Intravenous injection of (113)mIn-ENTMP and (99m)TcENTMP in dogs following coronary artery occlusion permitted a sequential double labeling of the damaged myocardium. (7) Since hyaluronidase is a very effective drug in reducing myocardial damage both in the experimental animal and in patients with acute myocardial infarction, a study was carried out to ascertain its effects on collateral flow

  17. Size effects in ductile cellular solids. Part II : experimental results

    NARCIS (Netherlands)

    Andrews, E.W.; Gioux, G.; Onck, P.; Gibson, L.J.

    2001-01-01

    There is increasing interest in the use of metallic foams in a variety of applications, including lightweight structural sandwich panels and energy absorption devices. In such applications, the mechanical response of the foams is of critical importance. In this study, we have investigated the effect

  18. Visual Accommodation, the Mandelbaum Effect, and Apparent Size.

    Science.gov (United States)

    1979-11-01

    ametropias are referred to as the anomalo i myoplas. (Leibowitz & Owens, 1975a). Tha QnK £oa. The laser optometer is particularly effective for investigating...the emmetropic observer. The situational ametropias could be considered anomalies, rejecting by fiat the possibility tnat they are a manifestation of an

  19. Effects of nanoscale size dependent parameters on lattice thermal ...

    Indian Academy of Sciences (India)

    diameter dependence also indicates a strong control of surface effect in surface to bulk ratio for the 22 nm wire diameter. ... dimensional systems of variable transverse dimension using a large scale numerical transverse .... include unharmonic interaction (three-phonon Umklapp scattering,τU ), mass difference scat-.

  20. Size and value effects in the Visegrad countries

    Czech Academy of Sciences Publication Activity Database

    Morgese Borys, M.; Zemčík, Petr

    -, č. 391 (2009), s. 1-28 ISSN 1211-3298 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:MSM0021620846 Keywords : regional asset pricing model * book-to- market value effects * Visegrad countries * cost of capital Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp391.pdf

  1. A qualitative test for intrinsic size effect on ferroelectric phase transitions

    OpenAIRE

    Wang, Jin; Tagantsev, Alexander K.; Setter, Nava

    2010-01-01

    The size effect in ferroelectrics is treated as a competition between the geometrical symmetry of the ferroelectric sample and its crystalline symmetry. The manifestation of this competition is shown to be polarization rotation, which is driven by temperature and/or size variations, thus providing a qualitative indication of intrinsic finite size effect on ferroelectrics. The concept is demonstrated in a simple case of PbTiO3 nanowires having their axis parallel to [111]C direction, where the...

  2. Influence of grain size on the extraordinary Hall effect in magnetic granular alloys

    International Nuclear Information System (INIS)

    Granovsky, Alexander B.; Kalitsov, Alan V.; Khanikaev, Alexander B.; Kioussis, Nicholas

    2003-01-01

    A quantum statistical theory of the influence of grain size on the residual extraordinary Hall effect (EHE) in magnetic metal-insulator granular alloys is presented. It is shown that under certain conditions the quasi-classical size-effect (QSE) can lead to similar behaviors of EHE in metal-metal and metal-insulator alloys. The possible dependences of EHE coefficient on the grain size and the role of the QSE in the giant EHE in nanocomposites are discussed

  3. Influence of grain size on the extraordinary Hall effect in magnetic granular alloys

    Energy Technology Data Exchange (ETDEWEB)

    Granovsky, Alexander B. E-mail: granov@magn.ru; Kalitsov, Alan V.; Khanikaev, Alexander B.; Kioussis, Nicholas

    2003-03-01

    A quantum statistical theory of the influence of grain size on the residual extraordinary Hall effect (EHE) in magnetic metal-insulator granular alloys is presented. It is shown that under certain conditions the quasi-classical size-effect (QSE) can lead to similar behaviors of EHE in metal-metal and metal-insulator alloys. The possible dependences of EHE coefficient on the grain size and the role of the QSE in the giant EHE in nanocomposites are discussed.

  4. Size effects in many-valley fluctuations in semiconductors

    International Nuclear Information System (INIS)

    Sokolov, V.N.; Kochelap, V.A.

    1995-08-01

    We present the results of theoretical investigations of nonhomogeneous fluctuations in submicron active regions of many-valley semiconductors with equivalent valleys(Ge, Si-type), where the dimension 2d of the region is comparable to or less than the intervalley diffusion relaxation length L iv . It is shown that for arbitrary orientations of the valley axes (the crystal axes) with respect to lateral sample surfaces, the fluctuation spectra depend on the bias voltage applied to the layer in the region of weak nonheating electric fields. The new physical phenomenon is reported: the fluctuation spectra depend on the sample thickness, with 2d iv the suppression of fluctuations arises for fluctuation frequencies ω -1 iv , τ -1 iv is the characteristic intervalley relaxation time. (author). 43 refs, 5 figs

  5. Debonding failure and size effects in micro reinforced composites

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang; Niordson, Christian Frithiof

    2010-01-01

    -plastic formulation. Bi-axially loaded unit cells are used and failure is modeled using a cohesive zone at the reinforcement interface. During debonding a sudden stress drop in the overall average stress–strain response is observed. Adaptive higher-order boundary conditions are imposed at the reinforcement interface...... for realistically modeling the restrictions on moving dislocations as debonding occurs. It is found that the influence of the imposed higher-order boundary conditions at the interface is minor. If strain-gradient effects are accounted for a void with a smooth shape develops at the reinforcement interface while...... a smaller void having a sharp tip nucleates if strain-gradient effects are excluded. Using orthogonalization of the plastic strain gradient with three corresponding material length scales it is found that, the first length scale dominates the evaluated overall average stress–strain response, the second one...

  6. No Effect of Featural Attention on Body Size Aftereffects

    OpenAIRE

    Stephen, Ian D.; Bickersteth, Chloe; Mond, Jonathan; Stevenson, Richard J.; Brooks, Kevin R.

    2016-01-01

    Prolonged exposure to images of narrow bodies has been shown to induce a perceptual aftereffect, such that observers’ point of subjective normality (PSN) for bodies shifts toward narrower bodies. The converse effect is shown for adaptation to wide bodies. In low-level stimuli, object attention (attention directed to the object) and spatial attention (attention directed to the location of the object) have been shown to increase the magnitude of visual aftereffects, while object-based attention...

  7. Coordinate based random effect size meta-analysis of neuroimaging studies.

    Science.gov (United States)

    Tench, C R; Tanasescu, Radu; Constantinescu, C S; Auer, D P; Cottam, W J

    2017-06-01

    Low power in neuroimaging studies can make them difficult to interpret, and Coordinate based meta-analysis (CBMA) may go some way to mitigating this issue. CBMA has been used in many analyses to detect where published functional MRI or voxel-based morphometry studies testing similar hypotheses report significant summary results (coordinates) consistently. Only the reported coordinates and possibly t statistics are analysed, and statistical significance of clusters is determined by coordinate density. Here a method of performing coordinate based random effect size meta-analysis and meta-regression is introduced. The algorithm (ClusterZ) analyses both coordinates and reported t statistic or Z score, standardised by the number of subjects. Statistical significance is determined not by coordinate density, but by a random effects meta-analyses of reported effects performed cluster-wise using standard statistical methods and taking account of censoring inherent in the published summary results. Type 1 error control is achieved using the false cluster discovery rate (FCDR), which is based on the false discovery rate. This controls both the family wise error rate under the null hypothesis that coordinates are randomly drawn from a standard stereotaxic space, and the proportion of significant clusters that are expected under the null. Such control is necessary to avoid propagating and even amplifying the very issues motivating the meta-analysis in the first place. ClusterZ is demonstrated on both numerically simulated data and on real data from reports of grey matter loss in multiple sclerosis (MS) and syndromes suggestive of MS, and of painful stimulus in healthy controls. The software implementation is available to download and use freely. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Rheology of Colombian coal-water slurry fuels: Effect of particle-size distribution

    Energy Technology Data Exchange (ETDEWEB)

    Pulido, J E; Rojas, C P; Acero, G [Universidad Industrial de Santander, Bucaramanga (Colombia)

    1996-12-31

    Coal-water slurry fuels (CWSF`s) have been prepared and characterized in a research project in Colombia, sponsored by Colciencias and Ecocarbon, in order to evaluate the effects of the different composition variables on the behavior during preparation and pipe line transportation. The authors have previously presented details describing the characteristics of the slurry fuels prepared with five types of Colombian thermal coals and the influence of their chemical composition on the optimum particle-size distribution (PSD) required to prepare highly loaded and workable CWSF`s. The formulation and design of flow systems of suspensions with high solids content, such as the CWSF`s, require a detailed rheological knowledge of the suspension in terms of the governing parameters related to PSD, coal content, surface chemistry of the particles and dispersants used to stabilize the slurries. Important studies on these aspects have been reviewed and carried out experimentally by other authors specially devoted to the correlations between apparent viscosity, solids content and average coal particle-size. One of the targets to obtain an optimum control on the viscosity and flow properties of the CWSF`s must be based in correlating the Theological constants for the prevailing model of viscosity law to the characteristic parameters of the particle-size distribution and to the coal content in the slurry. In spite of the effect of PSD on the rheology of highly-loaded coal slurries have been long recognized as significant, the specific influence of the various PSD`s on the parameters of the Theological model continues to receive attention to further understanding in order to improve the slurry formulations for a specified purpose on preparation and hydraulic handling. This paper reports the results of an experimental technique of examining the various PSD`s on coal slurry fuel rheology, taking special attention for the effect on the parameters of the rheological model.

  9. Predation, scramble competition, and the vigilance group size effect in dark-eyed juncos (Junco hyemalis)

    Science.gov (United States)

    Steven L. Lima; Patrick A. Zollner; Peter A. Bednekoff

    1999-01-01

    In socially feeding birds and mammals, as group size increases, individuals devote less time to scanning their environment and more time to feeding. This vigilance "group size effect" has long been attributed to the anti-predatory benefits of group living, but many investigators have suggested that this effect may be driven by scramble competition for limited...

  10. Effect Size Measures for Differential Item Functioning in a Multidimensional IRT Model

    Science.gov (United States)

    Suh, Youngsuk

    2016-01-01

    This study adapted an effect size measure used for studying differential item functioning (DIF) in unidimensional tests and extended the measure to multidimensional tests. Two effect size measures were considered in a multidimensional item response theory model: signed weighted P-difference and unsigned weighted P-difference. The performance of…

  11. On the origin of the cobalt particle size effects in Fischer−Tropsch catalysis

    NARCIS (Netherlands)

    den Breejen, J.P.|info:eu-repo/dai/nl/304837318; Radstake, P.B.|info:eu-repo/dai/nl/304829587; Bezemer, G.L.; Bitter, J.H.|info:eu-repo/dai/nl/160581435; Froseth, V.; Holmen, A.; de Jong, K.P.|info:eu-repo/dai/nl/06885580X

    2009-01-01

    The effects of metal particle size in catalysis are of prime scientific and industrial importance and call for a better understanding. In this paper the origin of the cobalt particle size effects in Fischer−Tropsch (FT) catalysis was studied. Steady-State Isotopic Transient Kinetic Analysis (SSITKA)

  12. Size and dimensionality effects in superconducting Mo thin films

    International Nuclear Information System (INIS)

    Fabrega, L; Gil, O; Camon, A; Parra-BorderIas, M; Fernandez-MartInez, I; Costa-Kraemer, J L; Briones, F; Sese, J; Gonzalez-Arrabal, R

    2011-01-01

    Molybdenum is a low T c , type I superconductor whose fundamental properties are poorly known. Its importance as an essential constituent of new high performance radiation detectors, the so-called transition edge sensors (TESs) calls for better characterization of this superconductor, especially in thin film form. Here we report on a study of the basic superconducting features of Mo thin films as a function of their thickness. The resistivity is found to rise and the critical temperature decreases on decreasing film thickness, as expected. More relevant, the critical fields along and perpendicular to the film plane are markedly different, thickness dependent and much larger than the thermodynamic critical field of Mo bulk. These results are consistent with a picture of type II 2D superconducting films, and allow estimates of the fundamental superconducting lengths of Mo. The role of morphology in determining the 2D and type II character of the otherwise type I molybdenum is discussed. The possible consequences of this behaviour on the performance of radiation detectors are also addressed.

  13. Addendum to "Finite-size effects on multibody neutrino exchange"

    CERN Document Server

    Abada, A; Rodríguez-Quintero, J

    1999-01-01

    The interaction energy of the neutrons due to massless neutrino exchange in a neutron star has recently been proved, using an effective theory, to be extremely small and infrared-safe. Our comment here is of conceptual order: two approaches to compute the total interaction energy density have recently been proposed. Here, we study the connection between these two approaches. From CP invariance, we argue that the resulting interaction energy has to be even in the parameter $b=-G_F n_n /\\sqrt{2}$, which expresses the static neutrino potential created by a neutron medium of density $n_n$.

  14. Nonlocal plasticity effects on interaction of different size voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Niordson, Christian Frithiof

    2004-01-01

    A nonlocal elastic-plastic material model is used to show that the rate of void growth is significantly reduced when the voids are small enough to be comparable with a characteristic material length. For a very small void in the material between much larger voids the competition between...... dimensional array of spherical voids. It is shown that the high growth rate of very small voids predicted by conventional plasticity theory is not realistic when the effect of a characteristic length, dependent on the dislocation structure, is accounted for. (C) 2003 Elsevier Ltd. All rights reserved....

  15. Preliminary report on the statistical evaluation of sorption data: Sorption as a function of mineralogy, temperature, time, and particle size

    International Nuclear Information System (INIS)

    Beckman, R.; Thomas, K.; Crowe, B.

    1988-05-01

    This report studies the transport of radionuclides from a repository to the environment by dissolution of the stored solid-waste form and subsequent transport in water. The sorption process may retard this movement of radionuclides from the repository to the accessible environment. A measure of this retardation process is the sorption ratio, R/sub D/, where R/sub D/ = (activity in solid phase per unit mass of solid)(activity in solution per unit volume of solution). In this study, predictions of the R/sub D/ values for the elements barium, cerium, cesium, europium, and strontium are developed from linear regression techniques. An R/sub D/ value was obtained for numerous drill core samples. Additional data include the particle size of the rock, temperature condition during the experiment, concentration of the sorbing element, and length of the sorption experiment. Preliminary regression results based on these data show that the temperature and length of the experiment are the most significant factors influencing the R/sub D/ values. Particle size has a slight effect, and based on a small amount of data, it appears that concentration had no effect. The x-ray diffraction data are used to classify the samples by mineralogy, and regression techniques are used to develop estimates of the R/sub D/ values. Zeolite abundance of 10% or more with some addition of clay increases the sorption values significantly. 12 refs., 3 figs., 6 tabs

  16. The finite-size effect in thin liquid crystal systems

    Science.gov (United States)

    Śliwa, I.

    2018-05-01

    Effects of surface ordering in liquid crystal systems confined between cell plates are of great theoretical and experimental interest. Liquid crystals introduced in thin cells are known to be strongly stabilized and ordered by cell plates. We introduce a new theoretical method for analyzing the effect of surfaces on local molecular ordering in thin liquid crystal systems with planar geometry of the smectic layers. Our results show that, due to the interplay between pair long-range intermolecular forces and nonlocal, relatively short-range, surface interactions, both orientational and translational orders of liquid crystal molecules across confining cells are very complex. In particular, it is demonstrated that the SmA, nematic, and isotropic phases can coexist. The phase transitions from SmA to nematic, as well as from nematic to isotropic phases, occur not simultaneously in the whole volume of the system but begin to appear locally in some regions of the LC sample. Phase transition temperatures are demonstrated to be strongly affected by the thickness of the LC system. The dependence of the corresponding shifts of phase transition temperatures on the layer number is shown to exhibit a power law character. This new type of scaling behavior is concerned with the coexistence of local phases in finite systems. The influence of a specific character of interactions of molecules with surfaces and other molecules on values of the resulting critical exponents is also analyzed.

  17. Size effects in electronic and catalytic properties of unsupported palladium nanoparticles in electrooxidation of formic acid.

    Science.gov (United States)

    Zhou, Wei Ping; Lewera, Adam; Larsen, Robert; Masel, Rich I; Bagus, Paul S; Wieckowski, Andrzej

    2006-07-13

    We report a combined X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and chronoamperometry (CA) study of formic acid electrooxidation on unsupported palladium nanoparticle catalysts in the particle size range from 9 to 40 nm. The CV and CA measurements show that the most active catalyst is made of the smallest (9 and 11 nm) Pd nanoparticles. Besides the high reactivity, XPS data show that such nanoparticles display the highest core-level binding energy (BE) shift and the highest valence band (VB) center downshift with respect to the Fermi level. We believe therefore that we found a correlation between formic acid oxidation current and BE and VB center shifts, which, in turn, can directly be related to the electronic structure of palladium nanoparticles of different particle sizes. Clearly, such a trend using unsupported catalysts has never been reported. According to the density functional theory of heterogeneous catalysis, and mechanistic considerations, the observed shifts are caused by a weakening of the bond strength of the COOH intermediate adsorption on the catalyst surface. This, in turn, results in the increase in the formic acid oxidation rate to CO2 (and in the associated oxidation current). Overall, our measurements demonstrate the particle size effect on the electronic properties of palladium that yields different catalytic activity in the HCOOH oxidation reaction. Our work highlights the significance of the core-level binding energy and center of the d-band shifts in electrocatalysis and underlines the value of the theory that connects the center of the d-band shifts to catalytic reactivity.

  18. The effect of grain size and phosphorous-doping of polycrystalline 3C–SiC on infrared reflectance spectra

    International Nuclear Information System (INIS)

    Rooyen, I.J. van; Engelbrecht, J.A.A.; Henry, A.; Janzén, E.; Neethling, J.H.; Rooyen, P.M. van

    2012-01-01

    Highlights: ► IR is investigated as a technique to measure grain size and P-doping of polycrystalline SiC. ► Infrared plasma minima can be used to determine doping levels in 3C–SiC for doping levels greater than 5 × 10 17 cm −3 . ► A linear relationship is found between FWHM and the inverse of grain size of 3C–SiC irrespective of P-doping level. ► It is further found that ω p is not influenced by the grain size. ► P-doping level has no significant effect on the linear relationship between grain size and surface roughness. - Abstract: The effect of P-doping and grain size of polycrystalline 3C–SiC on the infrared reflectance spectra is reported. The relationship between grain size and full width at half maximum (FWHM) suggest that the behavior of the 3C–SiC with the highest phosphorous doping level (of 1.2 × 10 19 at. cm −3 ) is different from those with lower doping levels ( 18 at. cm −3 ). It is also further demonstrated that the plasma resonance frequency (ω p ) is not influenced by the grain size.

  19. The effect of grain size and phosphorous-doping of polycrystalline 3C-SiC on infrared reflectance spectra

    Energy Technology Data Exchange (ETDEWEB)

    Rooyen, I.J. van, E-mail: Isabella.vanRooyen@inl.gov [Fuel Performance and Design Department, Idaho National Laboratory, Idaho Falls, ID 83415-6188 (United States); Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Engelbrecht, J.A.A. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Henry, A.; Janzen, E. [Department of Physics, Chemistry and Biology, Semiconductor Materials, Linkoeping University, Linkoeping 58183 (Sweden); Neethling, J.H. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Rooyen, P.M. van [Philip M van Rooyen Network Consultants, Midlands Estates (South Africa)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer IR is investigated as a technique to measure grain size and P-doping of polycrystalline SiC. Black-Right-Pointing-Pointer Infrared plasma minima can be used to determine doping levels in 3C-SiC for doping levels greater than 5 Multiplication-Sign 10{sup 17} cm{sup -3}. Black-Right-Pointing-Pointer A linear relationship is found between FWHM and the inverse of grain size of 3C-SiC irrespective of P-doping level. Black-Right-Pointing-Pointer It is further found that {omega}{sub p} is not influenced by the grain size. Black-Right-Pointing-Pointer P-doping level has no significant effect on the linear relationship between grain size and surface roughness. - Abstract: The effect of P-doping and grain size of polycrystalline 3C-SiC on the infrared reflectance spectra is reported. The relationship between grain size and full width at half maximum (FWHM) suggest that the behavior of the 3C-SiC with the highest phosphorous doping level (of 1.2 Multiplication-Sign 10{sup 19} at. cm{sup -3}) is different from those with lower doping levels (<6.6 Multiplication-Sign 10{sup 18} at. cm{sup -3}). It is also further demonstrated that the plasma resonance frequency ({omega}{sub p}) is not influenced by the grain size.

  20. Portion size effects on daily energy intake in low-income Hispanic and African American children and their mothers.

    Science.gov (United States)

    Fisher, Jennifer O; Arreola, Angeles; Birch, Leann L; Rolls, Barbara J

    2007-12-01

    Portion size influences children's energy intakes at meals, but effects on daily intake are unknown. Effects of large portions on daily energy intake were tested in 5-y-old Hispanic and African American children from low-income families. Maternal food intake data were collected to evaluate familial susceptibility to portion size. A within-subjects experimental design with reference and large portion sizes was used in a study of 59 low-income Hispanic and African American preschool-aged children and their mothers. The portion size of 3 entrées (lunch, dinner, and breakfast) and an afternoon snack served during a 24-h period were of a reference size in one condition and doubled in the other condition. Portion sizes of other foods and beverages did not vary across conditions. Weighed food intake, anthropometric measures, and self-reported data were obtained. Doubling the portion size of several entrées and a snack served during a 24-h period increased energy intake from those foods by 23% (180 kcal) among children (P kcal) among mothers (P daily intakes among Hispanic and African American children.

  1. The effects of particle size distribution and induced unpinning during grain growth

    International Nuclear Information System (INIS)

    Thompson, G.S.; Rickman, J.M.; Harmer, M.P.; Holm, E.A.

    1996-01-01

    The effect of a second-phase particle size distribution on grain boundary pinning was studied using a Monte Carlo simulation technique. Simulations were run using a constant number density of both whisker and rhombohedral particles, and the effect of size distribution was studied by varying the standard deviation of the distribution around a constant mean particle size. The results of present simulations indicate that, in accordance with the stereological assumption of the topological pinning model, changes in distribution width had no effect on the pinned grain size. The effect of induced unpinning of particles on microstructure was also studied. In contrast to predictions of the topological pinning model, a power law dependence of pinned grain size on particle size was observed at T=0.0. Based on this, a systematic deviation to the stereological predictions of the topological pinning model is observed. The results of simulations at higher temperatures indicate an increasing power law dependence of pinned grain size on particle size, with the slopes of the power law dependencies fitting an Arrhenius relation. The effect of induced unpinning of particles was also studied in order to obtain a correlation between particle/boundary concentration and equilibrium grain size. The results of simulations containing a constant number density of monosized rhombohedral particles suggest a strong power law correlation between the two parameters. copyright 1996 Materials Research Society

  2. The characteristics of Chinese orthographic neighborhood size effect for developing readers.

    Directory of Open Access Journals (Sweden)

    Jing Zhao

    Full Text Available Orthographic neighborhood size (N size effect in Chinese character naming has been studied in adults. In the present study, we aimed to explore the developmental characteristics of Chinese N size effect. One hundred and seventeen students (40 from the 3(rd grade with mean age of 9 years; 40 from the 5(th grade with mean age of 11 years; 37 from the 7(th grade with mean age of 13 years were recruited in the study. A naming task of Chinese characters was adopted to elucidate N-size- effect development. Reaction times and error rates were recorded. Results showed that children in the 3(rd grade named characters from large neighborhoods faster than named those from small neighborhoods, revealing a facilitatory N size effect; the 5(th graders showed null N size effect; while the 7(th graders showed an inhibitory N size effect, with longer reaction times for the characters from large neighborhoods than for those from small neighborhoods. The change from facilitation to inhibition of neighborhood size effect across grades suggested the transition from broadly tuned to finely tuned lexical representation in reading development, and the possible inhibition from higher frequency neighbors for higher graders.

  3. Grain size determination in zirconium alloys. Final report of a co-ordinated research programme, 1989-1992

    International Nuclear Information System (INIS)

    1995-04-01

    A research programme was planned as an exercise to establish procedures and evaluate the success of technology transfer. The first programme under this scheme was proposed by the IAEA on the research topic: grain size determination in zirconium alloys. The host laboratory was Siemens AG Erlangen, in Germany. The programme was supervised by experts selected from participating countries. This report contains the results of the work carried out under this programme. The grain size of Zircaloy, the measurement methods, distribution of grain size in the matrix and dependence of grain size on temperature time of annealing are discussed in this report. The report also includes some information on the organizational arrangements and discusses possibilities for future collaboration. 38 figs, 11 tabs

  4. Design of pressure-sensing diaphragm for MEMS capacitance diaphragm gauge considering size effect

    Science.gov (United States)

    Li, Gang; Li, Detian; Cheng, Yongjun; Sun, Wenjun; Han, Xiaodong; Wang, Chengxiang

    2018-03-01

    MEMS capacitance diaphragm gauge with a full range of (1˜1000) Pa is considered for its wide application prospect. The design of pressure-sensing diaphragm is the key to achieve balanced performance for this kind of gauges. The optimization process of the pressure-sensing diaphragm with island design of a capacitance diaphragm gauge based on MEMS technique has been reported in this work. For micro-components in micro scale range, mechanical properties are very different from that in the macro scale range, so the size effect should not be ignored. The modified strain gradient elasticity theory considering size effect has been applied to determine the bending rigidity of the pressure-sensing diaphragm, which is then used in the numerical model to calculate the deflection-pressure relation of the diaphragm. According to the deflection curves, capacitance variation can be determined by integrating over the radius of the diaphragm. At last, the design of the diaphragm has been optimized based on three parameters: sensitivity, linearity and ground capacitance. With this design, a full range of (1˜1000) Pa can be achieved, meanwhile, balanced sensitivity, resolution and linearity can be kept.

  5. Thermal and particle size distribution effects on the ferromagnetic resonance in magnetic fluids

    International Nuclear Information System (INIS)

    Marin, C.N.

    2006-01-01

    Thermal and particle size distribution effects on the ferromagnetic resonance of magnetic fluids were theoretically investigated, assuming negligible interparticle interactions and neglecting the viscosity of the carrier liquid. The model is based on the usual approach for the ferromagnetic resonance description of single-domain magnetic particle systems, which was amended in order to take into account the finite particle size effect, the particle size distribution and the orientation mobility of the particles within the magnetic fluid. Under these circumstances the shape of the resonance line, the resonance field and the line width are found to be strongly affected by the temperature and by the particle size distribution of magnetic fluids

  6. Influence of the molecular structure on indentation size effect in polymers

    International Nuclear Information System (INIS)

    Han, Chung-Souk

    2010-01-01

    Size dependent deformation of polymers has been observed by various researchers in various experimental settings including micro beam bending, foams and indentation testing. Here in this article the indentation size effect in polymers is examined which manifests itself in increased hardness at decreasing indentation depths. Based on previously suggested rationale of size dependent deformation and depth dependent hardness model the depth dependent hardness of various polymers are analyzed. It is found that polymers containing aromatic rings in their molecular structure exhibit depth dependent hardness above the micron length scale. For polymers not containing aromatic rings polymers the indentation size effect starts at smaller indentation depths if they are present at all.

  7. Testosterone sorption and desorption: Effects of soil particle size

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Yong, E-mail: yqi01@unomaha.edu [Civil Engineering Dept., University of Nebraska-Lincoln at Omaha Campus, Omaha, NE 68182 (United States); Zhang, Tian C. [Civil Engineering Dept., University of Nebraska-Lincoln at Omaha Campus, Omaha, NE 68182 (United States); Ren, Yongzheng [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-08-30

    Graphical abstract: - Highlights: • Smaller soil particles have higher sorption and lower desorption rates. • The sorption capacity ranks as clay > silt > sand. • Small particles like clays have less potential for desorption. • Colloids (clays) have high potential to facilitate the transport of hormones in soil–water environments. - Abstract: Soils contain a wide range of particles of different diameters with different mobility during rainfall events. Effects of soil particles on sorption and desorption behaviors of steroid hormones have not been investigated. In this study, wet sieve washing and repeated sedimentation methods were used to fractionate the soils into five ranges. The sorption and desorption properties and related mechanisms of testosterone in batch reactors filled with fractionated soil particles were evaluated. Results of sorption and desorption kinetics indicate that small soil particles have higher sorption and lower desorption rates than that of big ones. Thermodynamic results show the sorption processes are spontaneous and exothermal. The sorption capacity ranks as clay > silt > sand, depending mainly on specific surface area and surface functional groups. The urea control test shows that hydrogen bonding contributes to testosterone sorption onto clay and silt but not on sand. Desorption tests indicate sorption is 36–65% irreversible from clay to sand. Clays have highest desorption hysteresis among these five soil fractions, indicating small particles like clays have less potential for desorption. The results provide indirect evidence on the colloid (clay)-facilitated transport of hormones (micro-pollutants) in soil environments.

  8. Effects of emulsion droplet sizes on the crystallisation of milk fat.

    Science.gov (United States)

    Truong, Tuyen; Bansal, Nidhi; Sharma, Ranjan; Palmer, Martin; Bhandari, Bhesh

    2014-02-15

    The crystallisation properties of milk fat emulsions containing dairy-based ingredients as functions of emulsion droplet size, cooling rate, and emulsifier type were investigated using a differential scanning calorimeter (DSC). Anhydrous milk fat and its fractions (stearin and olein) were emulsified with whey protein concentrate, sodium caseinate, and Tween80 by homogenisation to produce emulsions in various size ranges (0.13-3.10 μm). Particle size, cooling rate, and types of emulsifier all had an influence on the crystallisation properties of fat in the emulsions. In general, the crystallisation temperature of emulsified fats decreased with decreasing average droplet size and was of an exponent function of size, indicating that the influence of particle size on crystallisation temperature is more pronounced in the sub-micron range. This particle size effect was also verified by electron microscopy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. The Banking Bailout of the Subprime Crisis: Size and Effects

    Directory of Open Access Journals (Sweden)

    Michele Fratianni

    2010-01-01

    Full Text Available This paper examines government policies aimed at rescuing banks from the effects of the great financial crisis of 2007-2009. To delimit the scope of the analysis, we concentrate on the fiscal side of interventions and ignore, by design, the monetary policy reaction to the crisis. The policy response to the subprime crisis started in earnest after Lehman's failure in mid September 2008, accelerated after February 2009, and has become very large by September 2009. Governments have relied on a portfolio of intervention tools, but the biggest commitments and outlays have been in the form of debt and asset guarantees, while purchases of bad assets have been very limited. We employ event study methodology to estimate the benefits of government interventions on banks and their shareholders. Announcements directed at the banking system as a whole (general and at specific banks (specific were priced by the markets as cumulative abnormal rates of return over the selected window periods. General announcements tend to be associated with positive cumulative abnormal returns and specific announcements with negative ones. General announcements exert cross-area spillovers but are perceived by the home-country banks as subsidies boosting the competitive advantage of foreign banks. Specific announcements exert spillovers on other banks. Our results are also sensitive to the information environment. Specific announcements tend to exert a positive impact on rates of return in the pre-crisis sub-period, when announcements are few and markets have relative confidence in the "normal" information flow. The opposite takes place in the turbulent crisis sub-period when announcements are the order of the day and markets mistrust the "normal" information flow. These results appear consistent with the observed reluctance of individual institutions to come forth with requests for public assistance.

  10. Comparison of known food weights with image-based portion-size automated estimation and adolescents' self-reported portion size.

    Science.gov (United States)

    Lee, Christina D; Chae, Junghoon; Schap, TusaRebecca E; Kerr, Deborah A; Delp, Edward J; Ebert, David S; Boushey, Carol J

    2012-03-01

    Diet is a critical element of diabetes self-management. An emerging area of research is the use of images for dietary records using mobile telephones with embedded cameras. These tools are being designed to reduce user burden and to improve accuracy of portion-size estimation through automation. The objectives of this study were to (1) assess the error of automatically determined portion weights compared to known portion weights of foods and (2) to compare the error between automation and human. Adolescents (n = 15) captured images of their eating occasions over a 24 h period. All foods and beverages served were weighed. Adolescents self-reported portion sizes for one meal. Image analysis was used to estimate portion weights. Data analysis compared known weights, automated weights, and self-reported portions. For the 19 foods, the mean ratio of automated weight estimate to known weight ranged from 0.89 to 4.61, and 9 foods were within 0.80 to 1.20. The largest error was for lettuce and the most accurate was strawberry jam. The children were fairly accurate with portion estimates for two foods (sausage links, toast) using one type of estimation aid and two foods (sausage links, scrambled eggs) using another aid. The automated method was fairly accurate for two foods (sausage links, jam); however, the 95% confidence intervals for the automated estimates were consistently narrower than human estimates. The ability of humans to estimate portion sizes of foods remains a problem and a perceived burden. Errors in automated portion-size estimation can be systematically addressed while minimizing the burden on people. Future applications that take over the burden of these processes may translate to better diabetes self-management. © 2012 Diabetes Technology Society.

  11. The effects of seed size on hybrids formed between oilseed rape (Brassica napus and wild brown mustard (B. juncea.

    Directory of Open Access Journals (Sweden)

    Yong-Bo Liu

    Full Text Available Seed size has significant implications in ecology, because of its effects on plant fitness. The hybrid seeds that result from crosses between crops and their wild relatives are often small, and the consequences of this have been poorly investigated. Here we report on plant performance of hybrid and its parental transgenic oilseed rape (Brassica napus and wild B. juncea, all grown from seeds sorted into three seed-size categories.Three seed-size categories were sorted by seed diameter for transgenic B. napus, wild B. juncea and their transgenic and non-transgenic hybrids. The seeds were sown in a field at various plant densities. Globally, small-seeded plants had delayed flowering, lower biomass, fewer flowers and seeds, and a lower thousand-seed weight. The seed-size effect varied among plant types but was not affected by plant density. There was no negative effect of seed size in hybrids, but it was correlated with reduced growth for both parents.Our results imply that the risk of further gene flow would probably not be mitigated by the small size of transgenic hybrid seeds. No fitness cost was detected to be associated with the Bt-transgene in this study.

  12. Surface bond contraction and its effect on the nanometric sized lead zirconate titanate

    International Nuclear Information System (INIS)

    Haitao Huang; Sun, Chang Q.; Hing, Peter

    2000-01-01

    The grain size effect of lead zirconate titanate PbZr 1-x Ti x O 3 (PZT, x≥0.6) caused by surface bond contraction has been investigated by using the Landau-Ginsburg-Devonshire (LGD) phenomenological theory. It has been shown that, due to the surface bond contraction, both the Curie temperature and the spontaneous polarization of tetragonal PZT decrease with decreasing grain size. These effects become more significant when the grain size is in the nanometre range. A dielectric anomaly appears with decreasing grain size, which corresponds to a size dependent phase transformation. The ferroelectric critical size below which a loss of ferroelectricity will happen is estimated from the results obtained. (author). Letter-to-the-editor

  13. Size effects in fcc crystals during the high rate compression test

    International Nuclear Information System (INIS)

    Yaghoobi, Mohammadreza; Voyiadjis, George Z.

    2016-01-01

    The present work studies the different mechanisms of size effects in fcc metallic samples of confined volumes during high rate compression tests using large scale atomistic simulation. Different mechanisms of size effects, including the dislocation starvation, source exhaustion, and dislocation source length effect are investigated for pillars with different sizes. The results show that the controlling mechanisms of size effects depend only on the pillar size and not on the value of applied strain. Dislocation starvation is the governing mechanism for very small pillars, i.e. pillars with diameters less than 30 nm. Increasing the pillar size, the dislocation exhaustion mechanism becomes active and there is no more source-limited activations. Next, the average dislocation source length is obtained and compared for pillars with different sizes. The results show that in the case of high rate deformations, the source length does not depend on the sample size, and the related size effects mechanisms are not active anymore. Also, in the case of high rate deformations, there are no size effects for pristine pillars with the diameters larger than 135 nm. In other words, increasing the strain rate decreases the pillar size at which there is no more size effects in the absence of strain gradient. The governing mechanisms of plastic deformation at high strain rate experiments are also different from those of the quasi-static tests. First, the diameter in which the dislocation nucleation at the free surface becomes the dominant mechanism changes from around 200 nm–30 nm. Next, in the case of the pillars with larger diameters, the plastic deformation is governed by the cross-slip instead of the operation of truncated dislocation sources, which is dominant at slower rates of deformation. In order to study the effects of pillar initial structure on the controlling mechanism of size effects, an initial loading and unloading procedure is conducted on some samples prior to the

  14. NMR Study of Solvation Effect on Geometry of Proton-Bound Homodimers of Increasing Size

    KAUST Repository

    Gurinov, Andrei A.; Denisov, Gleb S.; Borissova, Alexandra O.; Goloveshkin, Alexander S.; Greindl, Julian; Limbach, Hans-Heinrich; Shenderovich, Ilya G.

    2017-01-01

    Hydrogen bond geometries in the proton-bound homodimers of quinoline and acridine derivatives in an aprotic polar solution have been experimentally studied using 1H NMR at 120 K. The reported results show that increase of the dielec-tric permittivity of the medium results in contraction of the N…N distance. The degree of contraction depends on the homodimer's size and its substituent-specific solvation features. Neither of these effects can be reproduced using conven-tional implicit solvent models employed in computational studies. In general, the N…N distance in the homodimers of pyridine, quinoline, and acridine derivatives decreases in the sequence gas phase > solid state > polar solvent.

  15. NMR Study of Solvation Effect on Geometry of Proton-Bound Homodimers of Increasing Size

    KAUST Repository

    Gurinov, Andrei A.

    2017-10-24

    Hydrogen bond geometries in the proton-bound homodimers of quinoline and acridine derivatives in an aprotic polar solution have been experimentally studied using 1H NMR at 120 K. The reported results show that increase of the dielec-tric permittivity of the medium results in contraction of the N…N distance. The degree of contraction depends on the homodimer\\'s size and its substituent-specific solvation features. Neither of these effects can be reproduced using conven-tional implicit solvent models employed in computational studies. In general, the N…N distance in the homodimers of pyridine, quinoline, and acridine derivatives decreases in the sequence gas phase > solid state > polar solvent.

  16. Effect of laser spot size on energy balance in laser induced plasmas

    International Nuclear Information System (INIS)

    Pant, H.C.; Sharma, S.; Bhawalkar, D.D.

    1980-01-01

    The effect of the laser spot size on laser light absorption in laser induced plasmas from solid targets was studied. It was found that at a constant laser intensity on the target, reduction in the laser spot size enhances the net laser energy absorption. It was also observed that the laser light reflection from the target becomes more diffused when the focal spot size is reduced

  17. Children's accuracy of portion size estimation using digital food images: effects of interface design and size of image on computer screen.

    Science.gov (United States)

    Baranowski, Tom; Baranowski, Janice C; Watson, Kathleen B; Martin, Shelby; Beltran, Alicia; Islam, Noemi; Dadabhoy, Hafza; Adame, Su-heyla; Cullen, Karen; Thompson, Debbe; Buday, Richard; Subar, Amy

    2011-03-01

    To test the effect of image size and presence of size cues on the accuracy of portion size estimation by children. Children were randomly assigned to seeing images with or without food size cues (utensils and checked tablecloth) and were presented with sixteen food models (foods commonly eaten by children) in varying portion sizes, one at a time. They estimated each food model's portion size by selecting a digital food image. The same food images were presented in two ways: (i) as small, graduated portion size images all on one screen or (ii) by scrolling across large, graduated portion size images, one per sequential screen. Laboratory-based with computer and food models. Volunteer multi-ethnic sample of 120 children, equally distributed by gender and ages (8 to 13 years) in 2008-2009. Average percentage of correctly classified foods was 60·3 %. There were no differences in accuracy by any design factor or demographic characteristic. Multiple small pictures on the screen at once took half the time to estimate portion size compared with scrolling through large pictures. Larger pictures had more overestimation of size. Multiple images of successively larger portion sizes of a food on one computer screen facilitated quicker portion size responses with no decrease in accuracy. This is the method of choice for portion size estimation on a computer.

  18. Effect Size (Cohen's d of Cognitive Screening Instruments Examined in Pragmatic Diagnostic Accuracy Studies

    Directory of Open Access Journals (Sweden)

    Andrew J. Larner

    2014-07-01

    Full Text Available Background/Aims: Many cognitive screening instruments (CSI are available to clinicians to assess cognitive function. The optimal method comparing the diagnostic utility of such tests is uncertain. The effect size (Cohen's d, calculated as the difference of the means of two groups divided by the weighted pooled standard deviations of these groups, may permit such comparisons. Methods: Datasets from five pragmatic diagnostic accuracy studies, which examined the Mini-Mental State Examination (MMSE, the Mini-Mental Parkinson (MMP, the Six-Item Cognitive Impairment Test (6CIT, the Montreal Cognitive Assessment (MoCA, the Test Your Memory test (TYM, and the Addenbrooke's Cognitive Examination-Revised (ACE-R, were analysed to calculate the effect size (Cohen's d for the diagnosis of dementia versus no dementia and for the diagnosis of mild cognitive impairment versus no dementia (subjective memory impairment. Results: The effect sizes for dementia versus no dementia diagnosis were large for all six CSI examined (range 1.59-1.87. For the diagnosis of mild cognitive impairment versus no dementia, the effect sizes ranged from medium to large (range 0.48-1.45, with MoCA having the largest effect size. Conclusion: The calculation of the effect size (Cohen's d in diagnostic accuracy studies is straightforward. The routine incorporation of effect size calculations into diagnostic accuracy studies merits consideration in order to facilitate the comparison of the relative value of CSI.

  19. The effect of grain size and cement content on index properties of weakly solidified artificial sandstones

    Science.gov (United States)

    Atapour, Hadi; Mortazavi, Ali

    2018-04-01

    The effects of textural characteristics, especially grain size, on index properties of weakly solidified artificial sandstones are studied. For this purpose, a relatively large number of laboratory tests were carried out on artificial sandstones that were produced in the laboratory. The prepared samples represent fifteen sandstone types consisting of five different median grain sizes and three different cement contents. Indices rock properties including effective porosity, bulk density, point load strength index, and Schmidt hammer values (SHVs) were determined. Experimental results showed that the grain size has significant effects on index properties of weakly solidified sandstones. The porosity of samples is inversely related to the grain size and decreases linearly as grain size increases. While a direct relationship was observed between grain size and dry bulk density, as bulk density increased with increasing median grain size. Furthermore, it was observed that the point load strength index and SHV of samples increased as a result of grain size increase. These observations are indirectly related to the porosity decrease as a function of median grain size.

  20. The effect of cage size on reproductive performance and behavior of C57BL/6 mice.

    Science.gov (United States)

    Whitaker, Julia; Moy, Sheryl S; Saville, Benjamin R; Godfrey, Virginia; Nielsen, Judith; Bellinger, Dwight; Bradfield, John

    2007-11-01

    Scientific research has yet to conclusively determine the optimal cage size for mice. The authors examined the effect of cage size on mouse breeding performance and on offspring behavior, which can serve as indications of overall well-being. They housed breeding trios of C57BL/6Tac mice in standard or large individually ventilated cages and measured four reproductive parameters: litter size; litter survival to weaning age; average pup weight at 7, 14 and 21 days; and the number of days between litter births. They investigated the behavior of a subset of male and female pups from parents housed in cages of each size in the elevated plus maze test, the open field assay and the acoustic startle test. Cage size had no significant effect on any of the reproductive parameters measured and few or inconsistent effects on behavior in weaned pups.

  1. Finite size effects and chiral symmetry breaking in quenched three-dimensional QED

    International Nuclear Information System (INIS)

    Hands, S.; Kogut, J.B.

    1990-01-01

    Finite size effects and the chiral condensate are studied in three-dimensional QED by the Lanczos and the conjugate-gradient algorithms. Very substantial finite size effects are observed, but studies on L 3 lattices with L ranging from 8 to 80 indicate the development of a non-vanishing chiral condensate in the continuum limit of the theory. The systematics of the finite size effects and the fermion mass dependence in the conjugate-gradient algorithm are clarified in this extensive study. (orig.)

  2. Phenomenological theory of size effects in ultrafine ferroelectric particles (PbTiO3-type)

    International Nuclear Information System (INIS)

    Jiang, B.; Bursill, L.A.

    1998-01-01

    A new phenomenological model is proposed and discussed to study the size effects on phase transitions in PbTiO 3 -type ferroelectric particles. This model, by taking size effects on the phenomenological Landau-Ginzburg-Devonshire coefficients into consideration, can successfully explain the size effects on Curie temperature, c/a ratio, thermal and dielectric properties of lead-titanate-type ferroelectric particles. Theoretical and experimental results for PbTiO 3 fine particles are also compared and discussed. The relationship between the current model and the model of Zhong et al (Phys. Rev. B 50, 698 (1994)) is also presented. (authors)

  3. Effects of size and defects on the elasticity of silicon nanocantilevers

    NARCIS (Netherlands)

    Sadeghian, H.; Yang, C.K.; Goosen, J.F.L.; Bossche, A.; Staufer, U.; French, P.J.; Van Keulen, F.

    2010-01-01

    The size-dependent elastic behavior of silicon nanocantilevers and nanowires, specifically the effective Young’s modulus, has been determined by experimental measurements and theoretical investigations. The size dependence becomes more significant as the devices scale down from micro- to

  4. Effect of host plant on body size of Frankliniella occidentalis and its correlation with reproductive capacity

    NARCIS (Netherlands)

    Kogel, de W.J.; Bosco, D.; Hoek, van der M.; Mollema, C.

    1999-01-01

    The effect of different host plants on Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) body size was investigated. Thrips from three different populations, from the Netherlands, Italy, and USA, achieved greater body sizes when reared on cucumber than on bean. The same thrips grew

  5. Size effect model for the edge strength of glass with cut and ground edge finishing

    NARCIS (Netherlands)

    Vandebroek, M.; Louter, C.; Caspeele, R.; Ensslen, F.; Belis, J.L.I.F.

    2014-01-01

    The edge strength of glass is influenced by the size of the surface (near the edge) which is subjected to tensile stresses. To quantify this size effect, 8 series of single layer annealed glass beam specimens (as-received glass) were subjected to in-plane four-point bending with linearly increased

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

    Science.gov (United States)

    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…

  7. The Effect of Visual Feedback on Writing Size in Parkinson's Disease

    NARCIS (Netherlands)

    Potgieser, Adriaan R. E.; Roosma, Elizabeth; Beudel, Martijn; de Jong, Bauke M.

    2015-01-01

    Parkinson's disease (PD) leads to impairment in multiple cognitive domains. Micrographia is a relatively early PD sign of visuomotor dysfunction, characterized by a global reduction in writing size and a decrement in size during writing. Here we aimed to investigate the effect of withdrawal of

  8. Effect of particle size of granules on some mechanical properties of ...

    African Journals Online (AJOL)

    Solid dosage forms are invariably multiparticulate systems of heterogenous particle size distribution. The purpose of this study was to investigate the effect of particle size distribution of paracetamol granules on some tablet mechanical properties of paracetamol tablets. Granules were formed by wet massing paracetamol ...

  9. Effects of Group Size on Students Mathematics Achievement in Small Group Settings

    Science.gov (United States)

    Enu, Justice; Danso, Paul Amoah; Awortwe, Peter K.

    2015-01-01

    An ideal group size is hard to obtain in small group settings; hence there are groups with more members than others. The purpose of the study was to find out whether group size has any effects on students' mathematics achievement in small group settings. Two third year classes of the 2011/2012 academic year were selected from two schools in the…

  10. Morphological Family Size effects in L1 and L2 processing: An electrophysiological study

    NARCIS (Netherlands)

    Mulder, K.; Schreuder, R.; Dijkstra, A.F.J.

    2013-01-01

    The present study examined Morphological Family Size effects in first and second language processing. Items with a high or low Dutch (L1) Family Size were contrasted in four experiments involving Dutch–English bilinguals. In two experiments, reaction times (RTs) were collected in English (L2) and

  11. 77 FR 53769 - Receipts-Based, Small Business Size Standard; Confirmation of Effective Date

    Science.gov (United States)

    2012-09-04

    ... Flexibility Act of 1980, as amended. The NRC is increasing its receipts-based, small business size standard from $6.5 million to $7 million to conform to the standard set by the Small Business Administration...-Based, Small Business Size Standard; Confirmation of Effective Date AGENCY: Nuclear Regulatory...

  12. Effects of habitat size and quality on equilibrium density and extinction time of Sorex araneus populations

    NARCIS (Netherlands)

    Klok, C.; Roos, de A.M.

    1998-01-01

    1. The effects of changes in habitat size and quality on the expected population density and the expected time to extinction of Sorex araneus are studied by means of mathematical models that incorporate demographic stochasticity. 2. Habitat size is characterized by the number of territories, while

  13. Paying attention to attention: evidence for an attentional contribution to the size congruity effect.

    Science.gov (United States)

    Risko, Evan F; Maloney, Erin A; Fugelsang, Jonathan A

    2013-08-01

    Understanding the mechanisms supporting our comprehension of magnitude information represents a key goal in cognitive psychology. A major phenomenon employed in the pursuit of this goal has been the physical size congruity effect-namely, the observation that comparing the relative numerical sizes of two numbers is influenced by their relative physical sizes. The standard account of the physical size congruity effect attributes it to the automatic influence of the comparison of irrelevant physical magnitudes on numerical judgments. Here we develop an alternative account of this effect on the basis of the operation of attention in the typical size congruity display and the temporal dynamics of number comparison. We also provide a test of a number of predictions derived from this alternative account by combining a physical size congruity manipulation with a manipulation designed to alter the operation of attention within the typical size congruity display (i.e., a manipulation of the relative onsets of the digits). This test provides evidence consistent with an attentional contribution to the size congruity effect. Implications for our understanding of magnitude and the interactions between attention and magnitude are discussed.

  14. Formation of graphene on BN substrate by vapor deposition method and size effects on its structure

    Science.gov (United States)

    Giang, Nguyen Hoang; Hanh, Tran Thi Thu; Ngoc, Le Nhu; Nga, Nguyen To; Van Hoang, Vo

    2018-04-01

    We report MD simulation of the growth of graphene by the vapor deposition on a two-dimensional hBN substrate. The systems (containing carbon vapor and hBN substrate) are relaxed at high temperature (1500 K), and then it is cooled down to room one (300 K). Carbon atoms interact with the substrate via the Lennard-Jones potential while the interaction between carbon atoms is computed via the Tersoff potential. Depending on the size of the model, different crystalline honeycomb structures have been found. Structural properties of the graphene obtained at 300 K are studied by analyzing radial distribution functions (RDFs), coordination numbers, ring statistics, interatomic distances, bond-angle distributions and 2D visualization of atomic configurations. We find that the models containing various numbers of atoms have a honeycomb structure. Besides, differences in structural properties of graphene formed by the vapor deposition on the substrate and free standing one are found. Moreover, the size effect on the structure is significant.

  15. Effect of film size on drainage of foam and emulsion films

    International Nuclear Information System (INIS)

    Malhotra, A.K.; Wasan, D.T.

    1987-01-01

    All available theoretical analyses for the drainage of thin plane-parallel liquid films, such as those existing between two approaching liquid droplets or bubbles in the coalescence process, predict essentially the same dependence of rate of thinning of the intervening film on its size as is described by the Reynolds equation - that is, drainage time increases with the square of the film radius. Recently, the authors reported experimental data for both foam and emulsion films which showed that the measured drainage times increase with about a 0.8 power of the film radius, a value much smaller than the theoretically predicted value of 2.0. Here they present a hydrodynamic analysis to predict the experimentally observed effect of film size on the kinetics of thinning of emulsion and foam films. They extend the applicability of the Reynolds model by accounting for the flow in the Plateau borders as well as the London-van der Waals forces in the thin film phase. Their theoretical predictions are in good agreement with the experimental data on the dependence of drainage time of both foam and emulsion films on their radii

  16. Project appraisal for small and medium size wind energy installation: The Italian wind energy policy effects

    International Nuclear Information System (INIS)

    Fera, M.; Iannone, R.; Macchiaroli, R.; Miranda, S.; Schiraldi, M.M.

    2014-01-01

    In the last few years, the distributed energy production from small wind turbines (i.e.<200 kWp) has developed into a relevant business opportunity for different investors in Italy. The market, especially in Italy, has rapidly grown, achieving 9 MWp only in 2011, with an increase from 1.5 MW in 2009 to 13.3 MW at the end of 2011. This paper reports the results of a case study on the installation of several small wind turbines. It aims to provide an analysis of the conditions in Italy that make it possible to install these machines and offer a reliable reference for designing, planning, and controlling small wind turbine projects while focusing on the strategic variables of time, cost, and quality used by typical enterprises in the investment projects. The results are relevant to investors as well as engineering, procurement, and construction companies involved in this new sector, which must understand Italy’s renewable energy policy and its effects in practice. Moreover, certain national energy policy conclusions are reported and discussed in this paper. To properly study the sector, the data on time, cost and quality are analysed using typical project management tools. - Highlights: • Focus on the Italian wind energy sector. • Analysis of Italian policy effects. • Focus on small/medium size wind energy machines

  17. Vessel size effect on the characteristic frequency of the free surface fluctuations

    International Nuclear Information System (INIS)

    Nam, Ho Yun; Kim, Min Joon; Kim, Jong Man; Choi, Byoung Hae

    2004-01-01

    Studies of the free surface fluctuations is one of the important topics in a liquid metal nuclear reactor using sodium as the coolant that has a free surface in the upper plenum of the reactor vessel. The main reasons for the study on the free surface fluctuations can be summarized as: 1. to secure the structural integrity of a reactor vessel by considering the thermal stress on the vessel wall induced by the fluctuations of the free surface between the hot sodium and cold cover gas, 2. to prevent the cover gas entrainment at the free surface of the sodium because the entrained gas causes a change in the reactivity and also reduces the heat removal capability in the core. Some experimental studies on the free surface fluctuations have been reported. However, most of them focus on the gas entrainment phenomena and only a few works concern the basic characteristics of the free surface fluctuations. Since the thermal stress on the wall is strongly dependent on the amplitude and frequency of the free surface fluctuations, studies on the amplitudes and frequencies should receive more attention. In Nam, empirical formulae on the amplitudes and frequencies with respect to the geometric and hydraulic parameters were introduced. It is an interesting result, but the experiment was performed within the parameter range near the onset point of the fluctuations. In the real reactor condition, larger sized fluctuations may exist and the formula needs to be modified. In this study, we performed experiments on the free surface fluctuations, especially on larger sized fluctuations and made an analysis of the amplitudes and frequencies. The main focus of this paper is the effect of the vessel size on the characteristic frequencies. It is thought to be helpful for finding the scaling laws, for example, designing a scale-down experiment

  18. The effect of current density and saccharin addition on the grain size of nickel coatings

    Energy Technology Data Exchange (ETDEWEB)

    Uhm, Young Rang; Park, Keun Yung; Son, Kwang Jae; Shim, Young Ho; Choi, Sun Ju [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    Recently, the main advantage of a radioisotope 'fuel' is concentrated, because it is 'burned' at the rate of the isotopes half life. In other words, given a half life of 100 years, a nuclear battery would still produce half of its initial starting power after 100 years. A speck of a radioisotope like nickel 63, for example, contains enough energy to power a nano nuclear battery for decades, and to do so safely. Ni 63, a beta radiation source, is prepared by electrical deposition of radioactive Ni 63 ions on thin non radioactive nickel foil. Ni 63 plating is similar to other electroplating processes that employ soluble metal anodes. It requires the passage of a direct current between two electrodes that are immersed in a conductive, aqueous solution of nickel salts. The charged Ni ions are formed by sulfate, sulfamate, chloride, and a Watts bath. However, the charged Ni 63 ions are formed by dissolving metal Ni 63. To establish the coating condition of Ni 63, non radioactive metal Ni particles were dissolved in an acid solution and electroplated on the Ni sheet. A continuous increase in the grain size versus current density has also been recognized in the direct current electrodeposition of nickel coating. On the other hand, A runa et al. reported that the current density has no significant effect on the grain size of nickel electro deposits. A review of the literature shows that saccharin has often been added to a nickel plating bath since the 1980s to improve the ductility and brightness, and in later periods as a grain refiner agent. In the present paper, not only the preparation of the Ni plating solution prepared by dissolving metal particles but also an optimization of the deposition conditions, such as the influence of current density and saccharin concentration on the grain size, was investigated. The proposed model can also be applied for radioactive Ni 63 electroplating.

  19. The effect of current density and saccharin addition on the grain size of nickel coatings

    International Nuclear Information System (INIS)

    Uhm, Young Rang; Park, Keun Yung; Son, Kwang Jae; Shim, Young Ho; Choi, Sun Ju

    2012-01-01

    Recently, the main advantage of a radioisotope 'fuel' is concentrated, because it is 'burned' at the rate of the isotopes half life. In other words, given a half life of 100 years, a nuclear battery would still produce half of its initial starting power after 100 years. A speck of a radioisotope like nickel 63, for example, contains enough energy to power a nano nuclear battery for decades, and to do so safely. Ni 63, a beta radiation source, is prepared by electrical deposition of radioactive Ni 63 ions on thin non radioactive nickel foil. Ni 63 plating is similar to other electroplating processes that employ soluble metal anodes. It requires the passage of a direct current between two electrodes that are immersed in a conductive, aqueous solution of nickel salts. The charged Ni ions are formed by sulfate, sulfamate, chloride, and a Watts bath. However, the charged Ni 63 ions are formed by dissolving metal Ni 63. To establish the coating condition of Ni 63, non radioactive metal Ni particles were dissolved in an acid solution and electroplated on the Ni sheet. A continuous increase in the grain size versus current density has also been recognized in the direct current electrodeposition of nickel coating. On the other hand, A runa et al. reported that the current density has no significant effect on the grain size of nickel electro deposits. A review of the literature shows that saccharin has often been added to a nickel plating bath since the 1980s to improve the ductility and brightness, and in later periods as a grain refiner agent. In the present paper, not only the preparation of the Ni plating solution prepared by dissolving metal particles but also an optimization of the deposition conditions, such as the influence of current density and saccharin concentration on the grain size, was investigated. The proposed model can also be applied for radioactive Ni 63 electroplating

  20. Covariate adjustments in randomized controlled trials increased study power and reduced biasedness of effect size estimation.

    Science.gov (United States)

    Lee, Paul H

    2016-08-01

    This study aims to show that under several assumptions, in randomized controlled trials (RCTs), unadjusted, crude analysis will underestimate the Cohen's d effect size of the treatment, and an unbiased estimate of effect size can be obtained only by adjusting for all predictors of the outcome. Four simulations were performed to examine the effects of adjustment on the estimated effect size of the treatment and power of the analysis. In addition, we analyzed data from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study (older adults aged 65-94), an RCT with three treatment arms and one control arm. We showed that (1) the number of unadjusted covariates was associated with the effect size of the treatment; (2) the biasedness of effect size estimation was minimized if all covariates were adjusted for; (3) the power of the statistical analysis slightly decreased with the number of adjusted noise variables; and (4) exhaustively searching the covariates and noise variables adjusted for can lead to exaggeration of the true effect size. Analysis of the ACTIVE study data showed that the effect sizes adjusting for covariates of all three treatments were 7.39-24.70% larger than their unadjusted counterparts, whereas the effect size would be elevated by at most 57.92% by exhaustively searching the variables adjusted for. All covariates of the outcome in RCTs should be adjusted for, and if the effect of a particular variable on the outcome is unknown, adjustment will do more good than harm. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Computational analysis of the atomic size effect in bulk metallic glasses and their liquid precursors

    International Nuclear Information System (INIS)

    Kokotin, V.; Hermann, H.

    2008-01-01

    The atomic size effect and its consequences for the ability of multicomponent liquid alloys to form bulk metallic glasses are analyzed in terms of the generalized Bernal's model for liquids, following the hypothesis that maximum density in the liquid state improves the glass-forming ability. The maximum density that can be achieved in the liquid state is studied in the 2(N-1) dimensional parameter space of N-component systems. Computer simulations reveal that the size ratio of largest to smallest atoms are most relevant for achieving the maximum packing for N = 3-5, whereas the number of components plays a minor role. At small size ratio, the maximum packing density can be achieved by different atomic size distributions, whereas for medium size ratios the maximum density is always correlated to a concave size distribution. The relationship of the results to Miracle's efficient cluster packing model is also discussed

  2. Big Money: The Effect of Money Size on Value Perceptions and Saving Motivation.

    Science.gov (United States)

    Peetz, Johanna; Soliman, Monica

    2016-01-28

    Motivated perception has been shown to affect people's estimates of money (e.g., perceiving coins as larger than real size). In the present research, we examine whether simply varying the size of a picture of money can affect its perceived value and subsequent decisions. Participants presented with a picture of money enlarged by 15% perceived the depicted money as more valuable compared with those seeing a real-size picture (Study 1). When told to imagine their own cash and banked money in the depicted form, participants presented with a picture enlarged by 15% felt more subjectively wealthy and reported fewer intentions to conserve their money compared with those seeing a real-size picture of the same money (Study 2). Together, these studies suggest that judgments about money and even attitudes toward personal spending can be influenced by manipulating the size of a picture of money. © The Author(s) 2016.

  3. Maternal effects and the evolution of brain size in birds: overlooked developmental constraints.

    Science.gov (United States)

    Garamszegi, L Z; Biard, C; Eens, M; Møller, A P; Saino, N; Surai, P

    2007-01-01

    A central dogma for the evolution of brain size posits that the maintenance of large brains incurs developmental costs, because they need prolonged periods to grow during the early ontogeny. Such constraints are supported by the interspecific relationship between ontological differences and relative brain size in birds and mammals. Given that mothers can strongly influence the development of the offspring via maternal effects that potentially involve substances essential for growing brains, we argue that such effects may represent an important but overlooked component of developmental constraints on brain size. To demonstrate the importance of maternal effect on the evolution of brains, we investigated the interspecific relationship between relative brain size and maternal effects, as reflected by yolk testosterone, carotenoids, and vitamins A and E in a phylogenetic study of birds. Females of species with relatively large brains invested more in eggs in terms of testosterone and vitamin E than females of species with small brains. The effects of carotenoid and vitamin A levels on the evolution of relative brain size were weaker and non-significant. The association between relative brain size and yolk testosterone was curvilinear, suggesting that very high testosterone levels can be suppressive. However, at least in moderate physiological ranges, the positive relationship between components of maternal effects and relative brain size may imply one aspect of developmental costs of large brains. The relationship between vitamin E and relative brain size was weakened when we controlled for developmental mode, and thus the effect of this antioxidant may be indirect. Testosterone-enhanced neurogenesis and vitamin E-mediated defence against oxidative stress may have key functions when the brain of the embryo develops, with evolutionary consequences for relative brain size.

  4. Athabasca--special report No. 2, sand behavior key to operation size

    Energy Technology Data Exchange (ETDEWEB)

    Daly, W J

    1966-09-01

    Before production of the crude oil from the Athabasca tar sands could be initiated, a feasibility and economic study based on field test work was made. It was concluded that the project was technically feasible and a plant could be constructed for approximately $137 million, but that the engineering design must be preceded by a field test program, laboratory work, and by ground surveys. A test program, using the hot water recovery process and sized to handle 3 tons of sand per hour, was begun in Oct. 1963. As the test program proceeded, the unit was frequently renovated as capacity was increased from 3 tons to finally 10 tons per hour. Included in the tests was the determination of the effect that raw bitumen pools (indicated by the government coring program) would have on production operations. It was determined that no problems would arise from this situation because no such pools could be found and were considered not to be in existence. The test model was successful in clearly illustrating the principles to use in the overall layout, which is approximately 50% complete.

  5. Size effect on deformation twinning in face-centred cubic single crystals: Experiments and modelling

    International Nuclear Information System (INIS)

    Liang, Z.Y.; De Hosson, J.T.M.; Huang, M.X.

    2017-01-01

    In addition to slip by dislocation glide, deformation twinning in small-sized metallic crystals also exhibits size effect, namely the twinning stress increases with decreasing sample size. In order to understand the underpinning mechanisms responsible for such effect, systematic experiments were carried out on the small-sized single-crystalline pillars of a twinning-induced plasticity steel with a face-centred cubic structure. The flow stress increases considerably with decreasing pillar diameter from 3 to 0.5 μm, demonstrating a substantial size effect with a power exponent of 0.43. Detailed microstructural characterization reveals that the plastic deformation of the present pillars is dominant by twinning, primarily via twin growth, indicating that the size effect should be related to deformation twinning instead of slip by dislocation glide. Subsequent modelling works indicate that twinning can be accomplished by the dissociation of the ion-radiation-induced vacancy Frank loops in the damaged subsurface layer of the pillars, and the size effect is attributed to the ion-radiation-induced compressive stress in the subsurface layer, which decreases with pillar diameter.

  6. Numerical study on channel size effect for proton exchange membrane fuel cell with serpentine flow field

    International Nuclear Information System (INIS)

    Wang Xiaodong; Yan Weimon; Duan Yuanyuan; Weng Fangbor; Jung Guobin; Lee Chiyuan

    2010-01-01

    This work numerically investigates the effect of the channel size on the cell performance of proton exchange membrane (PEM) fuel cells with serpentine flow fields using a three-dimensional, two-phase model. The local current densities in the PEM, oxygen mass flow rates and liquid water concentrations at the interface of the cathode gas diffusion layer and catalyst layer were analyzed to understand the channel size effect. The predictions show that smaller channel sizes enhance liquid water removal and increase oxygen transport to the porous layers, which improve cell performance. Additionally, smaller channel sizes also provide more uniform current density distributions in the cell. However, as the channel size decreases, the total pressure drops across the cell increases, which leads to more pump work. With taking into account the pressure losses, the optimal cell performance occurs for a cell with a flow channel cross-sectional area of 0.535 x 0.535 mm 2 .

  7. Estimation of the ancestral effective population sizes of African great apes under different selection regimes.

    Science.gov (United States)

    Schrago, Carlos G

    2014-08-01

    Reliable estimates of ancestral effective population sizes are necessary to unveil the population-level phenomena that shaped the phylogeny and molecular evolution of the African great apes. Although several methods have previously been applied to infer ancestral effective population sizes, an analysis of the influence of the selective regime on the estimates of ancestral demography has not been thoroughly conducted. In this study, three independent data sets under different selective regimes were used were composed to tackle this issue. The results showed that selection had a significant impact on the estimates of ancestral effective population sizes of the African great apes. The inference of the ancestral demography of African great apes was affected by the selection regime. The effects, however, were not homogeneous along the ancestral populations of great apes. The effective population size of the ancestor of humans and chimpanzees was more impacted by the selection regime when compared to the same parameter in the ancestor of humans, chimpanzees and gorillas. Because the selection regime influenced the estimates of ancestral effective population size, it is reasonable to assume that a portion of the discrepancy found in previous studies that inferred the ancestral effective population size may be attributable to the differential action of selection on the genes sampled.

  8. Family size, the physical environment, and socioeconomic effects across the stature distribution.

    Science.gov (United States)

    Carson, Scott Alan

    2012-04-01

    A neglected area in historical stature studies is the relationship between stature and family size. Using robust statistics and a large 19th century data set, this study documents a positive relationship between stature and family size across the stature distribution. The relationship between material inequality and health is the subject of considerable debate, and there was a positive relationship between stature and wealth and an inverse relationship between stature and material inequality. After controlling for family size and wealth variables, the paper reports a positive relationship between the physical environment and stature. Copyright © 2012 Elsevier GmbH. All rights reserved.

  9. Effect of grain size on corrosion of nanocrystalline copper in NaOH solution

    International Nuclear Information System (INIS)

    Luo Wei; Xu Yimin; Wang Qiming; Shi Peizhen; Yan Mi

    2010-01-01

    Research highlights: → Coppers display an active-passive-transpassive behaviour with duplex passive film. → Grain size variation has little effect on the overall corrosion behaviour of Cu. → Little effect on corrosion may be due to duplex passivation in NaOH solution. → Bulk nanocrystalline Cu show bamboo-like flake corrosion structure. - Abstract: Effect of grain size on corrosion of bulk nanocrystalline copper was investigated using potentiodynamic polarization measurements in 0.1 M NaOH solution. Bulk nanocrystalline copper was prepared by inert gas condensation and in situ warm compress (IGCWC) method. The grain sizes of all bulk nanocrystalline samples were determined to be 48, 68 and 92 nm using X-ray diffraction (XRD). Results showed that bulk coppers displayed an active-passive-transpassive behaviour with duplex passive films. From polycrystalline to nanocrystalline, grain size variation showed little effect on the overall corrosion resistance of copper samples.

  10. A Simple Size Effect Model for Tension Perpendicular to the Grain

    DEFF Research Database (Denmark)

    Pedersen, M. U.; Clorius, Christian Odin; Damkilde, Lars

    2003-01-01

    The strength in tension perpendicular to the grain is known to decrease with an increase in the stressed volume. Usually this size effect is explained on a stochastic basis, that is, an explanation relying on the increased probability of encountering a strength reducing flaw when the volume...... of the material under stress is increased. This paper presents an experimental investigation on specimens with a well-defined structural orientation of the material. The experiments exhibit a large size effect and the nature of the failures encountered suggests that the size effect can be explained...... on a deterministic basis. Arguments for such a simple deterministic explanation of size effect is found in finite element modelling, using the orthotropic stiffness characteristics in the transverse plane of wood....

  11. Deconstruction of Vulnerability to Complex Diseases: Enhanced Effect Sizes and Power of Intermediate Phenotypes

    Directory of Open Access Journals (Sweden)

    David Goldman

    2007-01-01

    Full Text Available The deconstruction of vulnerability to complex disease with the help of intermediate phenotypes, including the heritable and disease-associated endophenotypes, is a legacy of Henri Begleiter. Systematic searches for genes influencing complex disorders, including bipolar disorder, have recently been completed using whole genome association (WGA, identifying a series of validated loci. Using this information, it is possible to compare effect sizes of disease loci discovered in very large samples to the effect sizes of replicated functional loci determining intermediate phenotypes that are of essential interest in psychiatric disorders. It is shown that the genes influencing intermediate phenotypes tend to have a larger effect size. Furthermore, the WGA results reveal that the number of loci of large effect size for complex diseases is limited, and yet multiple functional loci have already been identified for intermediate phenotypes relevant to psychiatric diseases, and without the benefit of WGA.

  12. Rate of inbreeding and effective population size in four major South ...

    African Journals Online (AJOL)

    huis

    Keywords: Dairy cattle, genetic diversity, pedigree analysis ... inbreeding and effective population sizes for the four major South African ... breeding programs and therefore L was computed as an average of generation intervals for the four.

  13. Effect of interaction between seed size and sowing depth of cashew ...

    African Journals Online (AJOL)

    Effect of interaction between seed size and sowing depth of cashew Anacardium occidentale (L) on seedlings emergence and height under treatment with organic and inorganic fertilizer in Gidan-Waya, Southern Guinea Savanna, Nigeria.

  14. Effect of particle size and distribution of the sizing agent on the carbon fibers surface and interfacial shear strength (IFSS) of its composites

    International Nuclear Information System (INIS)

    Zhang, R.L.; Liu, Y.; Huang, Y.D.; Liu, L.

    2013-01-01

    Effect of particle size and distribution of the sizing agent on the performance of carbon fiber and carbon fiber composites has been investigated. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to characterize carbon fiber surface topographies. At the same time, the single fiber strength and Weibull distribution were also studied in order to investigate the effect of coatings on the fibers. The interfacial shear strength and hygrothermal aging of the carbon fiber/epoxy resin composites were also measured. The results indicated that the particle size and distribution is important for improving the surface of carbon fibers and its composites performance. Different particle size and distribution of sizing agent has different contribution to the wetting performance of carbon fibers. The fibers sized with P-2 had higher value of IFSS and better hygrothermal aging resistant properties.

  15. Effects of diffraction and target finite size on coherent transition radiation spectra in bunch length measurements

    Energy Technology Data Exchange (ETDEWEB)

    Castellano, M.; Cianchi, A.; Verzilov, V.A. [Istituto Nazionale di Fisica Nucleare, Frascati, RM (Italy). Laboratori Nazionali di Frascati; Orlandi, G. [Istituto Nazionale di Fisica Nucleare, Rome (Italy)]|[Rome Univ., Tor Vergata, Rome (Italy)

    1999-07-01

    Effects of diffraction and the size of the target on TR in the context of CTR-based bunch length measurements are studied on the basis of Kirchhoff diffraction theory. Spectra of TR from the finite-size target for several schemes of measurements are calculated in the far-infrared region showing strong distortion at low frequencies. Influence of the effect on the accuracy of bunch length measurements is estimated.

  16. Bayesian sample size determination for cost-effectiveness studies with censored data.

    Directory of Open Access Journals (Sweden)

    Daniel P Beavers

    Full Text Available Cost-effectiveness models are commonly utilized to determine the combined clinical and economic impact of one treatment compared to another. However, most methods for sample size determination of cost-effectiveness studies assume fully observed costs and effectiveness outcomes, which presents challenges for survival-based studies in which censoring exists. We propose a Bayesian method for the design and analysis of cost-effectiveness data in which costs and effectiveness may be censored, and the sample size is approximated for both power and assurance. We explore two parametric models and demonstrate the flexibility of the approach to accommodate a variety of modifications to study assumptions.

  17. Theory of critical phenomena in finite-size systems scaling and quantum effects

    CERN Document Server

    Brankov, Jordan G; Tonchev, Nicholai S

    2000-01-01

    The aim of this book is to familiarise the reader with the rich collection of ideas, methods and results available in the theory of critical phenomena in systems with confined geometry. The existence of universal features of the finite-size effects arising due to highly correlated classical or quantum fluctuations is explained by the finite-size scaling theory. This theory (1) offers an interpretation of experimental results on finite-size effects in real systems; (2) gives the most reliable tool for extrapolation to the thermodynamic limit of data obtained by computer simulations; (3) reveals

  18. Effect of pore size distribution and flow segregation on dispersion in porous media

    International Nuclear Information System (INIS)

    Carbonell, R.G.

    1978-11-01

    In order to study the effect of the pore size distribution and flow segregation on dispersion in a porous media, the dispersion of solute in an array of parallel pores is considered. Equations are obtained for the dispersion coefficient in laminar and turbulent flow, as a function of the particle Peclet number. The theory fits quite well cumulative experimental data from various researchers in the Peclet number range from 10 -3 to 10 6 . The model also predicts some trends, backed by experimental data, regarding the effect of particle size, particle size distribution and fluid velocity on dispersion

  19. Response trajectories capture the continuous dynamics of the size congruity effect.

    Science.gov (United States)

    Faulkenberry, Thomas J; Cruise, Alexander; Lavro, Dmitri; Shaki, Samuel

    2016-01-01

    In a comparison task involving numbers, the size congruity effect refers to the general finding that responses are usually faster when there is a match between numerical size and physical size (e.g., 2-8) than when there is a mismatch (e.g., 2-8). In the present study, we used computer mouse tracking to test two competing models of the size congruity effect: an early interaction model, where interference occurs at an early representational stage, and a late interaction model, where interference occurs as dynamic competition between response options. In three experiments, we found that the curvature of responses for incongruent trials was greater than for congruent trials. In Experiment 2 we showed that this curvature effect was reliably modulated by the numerical distance between the two stimulus numbers, with large distance pairs exhibiting a larger curvature effect than small distance pairs. In Experiment 3 we demonstrated that the congruity effects persist into response execution. These findings indicate that incongruities between numerical and physical sizes are carried throughout the response process and result from competition between parallel and partially active response options, lending further support to a late interaction model of the size congruity effect. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. A comparative study on the effective thermal conductivity of a single size beryllium pebble bed

    International Nuclear Information System (INIS)

    Abou-Sena, A.; Ying, A.; Abdou, M.

    2004-01-01

    Solid breeder blankets generally use beryllium-helium pebble beds to ensure sufficient tritium breeding. The data of the effective thermal conductivity, k eff , of beryllium pebble beds is important to the design of fusion blankets. It serves as a database for benchmarking the models of pebble beds. The objective of this paper is to review and compare the available data (obtained by several studies) of the effective thermal conductivity of beryllium pebble beds in order to address the current status of these data. Two comparisons are presented: one for the data of k eff versus bed mean temperature and the second one for the data of k eff versus external applied pressures. The data (k eff versus bed temperature) reported by Enoeda et al., Dalle Donne et al., and UCLA, have a similar particle size and packing fraction. Despite their similarity, the standard deviation values of their data are around 32%. Also, the data of the effective thermal conductivity as a function of mechanical pressure have standard deviation values of ∼50%. From the presented comparisons, significant discrepancies among the available data of k eff of the beryllium pebble beds were observed. These discrepancies may be attributed to the apparent differences among available studies, such as experiment technique, packing fraction, particle characteristics, bed dimensions, and temperature range and gradient across the bed. (author)

  1. Beyond size–number trade-offs: clutch size as a maternal effect

    Science.gov (United States)

    Brown, Gregory P.; Shine, Richard

    2009-01-01

    Traditionally, research on life-history traits has viewed the link between clutch size and offspring size as a straightforward linear trade-off; the product of these two components is taken as a measure of maternal reproductive output. Investing more per egg results in fewer but larger eggs and, hence, offspring. This simple size–number trade-off has proved attractive to modellers, but our experimental studies on keelback snakes (Tropidonophis mairii, Colubridae) reveal a more complex relationship between clutch size and offspring size. At constant water availability, the amount of water taken up by a snake egg depends upon the number of adjacent eggs. In turn, water uptake affects hatchling size, and therefore an increase in clutch size directly increases offspring size (and thus fitness under field conditions). This allometric advantage may influence the evolution of reproductive traits such as growth versus reproductive effort, optimal age at female maturation, the body-reserve threshold required to initiate reproduction and nest-site selection (e.g. communal oviposition). The published literature suggests that similar kinds of complex effects of clutch size on offspring viability are widespread in both vertebrates and invertebrates. Our results also challenge conventional experimental methodologies such as split-clutch designs for laboratory incubation studies: by separating an egg from its siblings, we may directly affect offspring size and thus viability. PMID:19324614

  2. THE EVOLUTIONARY GENETICS OF AN ADAPTIVE MATERNAL EFFECT: EGG SIZE PLASTICITY IN A SEED BEETLE.

    Science.gov (United States)

    Fox, Charles W; Czesak, Mary Ellen; Mousseau, Timothy A; Roff, Derek A

    1999-04-01

    In many organisms, a female's environment provides a reliable indicator of the environmental conditions that her progeny will encounter. In such cases, maternal effects may evolve as mechanisms for transgenerational phenotypic plasticity whereby, in response to a predictive environmental cue, a mother can change the type of eggs that she makes or can program a developmental switch in her offspring, which produces offspring prepared for the environmental conditions predicted by the cue. One potentially common mechanism by which females manipulate the phenotype of their progeny is egg size plasticity, in which females vary egg size in response to environmental cues. We describe an experiment in which we quantify genetic variation in egg size and egg size plasticity in a seed beetle, Stator limbatus, and measure the genetic constraints on the evolution of egg size plasticity, quantified as the genetic correlation between the size of eggs laid across host plants. We found that genetic variation is present within populations for the size of eggs laid on seeds of two host plants (Acacia greggii and Cercidium floridum; h 2 ranged between 0.217 and 0.908), and that the heritability of egg size differed between populations and hosts (higher on A. greggii than on C. floridum). We also found that the evolution of egg size plasticity (the maternal effect) is in part constrained by a high genetic correlation across host plants (r G > 0.6). However, the cross-environment genetic correlation is less than 1.0, which indicates that the size of eggs laid on these two hosts can diverge in response to natural selection and that egg size plasticity is thus capable of evolving in response to natural selection. © 1999 The Society for the Study of Evolution.

  3. Effects of Stocking Density or Group Size on Intake, Growth, and Meat Quality of Hanwoo Steers (

    Directory of Open Access Journals (Sweden)

    Sang Moo Lee

    2012-11-01

    Full Text Available This study was conducted to investigate the effects of stocking density or group size on feed intake, daily gain, and carcass characteristics of Hanwoo (Korean indigenous breed steers reared from 7 months to 31 months of age. Thirty Hanwoo steers were divided into four groups with three replicates each (a total of 12 pens. In each group, one (G1, two (G2, three (G3, and four steers (G4 per pen were allocated as treatments. Pen size was 32.0 m2, and therefore Hanwoo steers in G1, G2, G3, and G4 were reared under different space allowances, i.e. 32.0, 16.0, 10.6, and 8.0 m2/steer, respectively. Steers were reared following a conventional beef cattle management method in Korea, and were offered a fixed amount of commercial concentrate with ad libitum forages. Results were subjected to analysis of variance with stocking density as the main effect, and significance was declared at p<0.05. Although total feed intake was not significantly altered, it numerically increased in animals of low stocking density (G1 compared to those subjected to high stocking density treatment (i.e. G4. Feed conversion ratio was higher (p<0.05 in G3 compared to G1 and G2. Animals in G1 (low stocking density grew faster (p<0.05 than those of high stocking density (G3 and G4. Back fat thickness, meat yield index, and meat yield grade were similar among all levels of stocking density. However, longissimus muscle area was larger in G1 and G2 (p<0.01 compared to G3 and G4, and animals in G3 produced smaller carcasses (p<0.05. Carcass quality traits, including marbling score, meat color, fat color, texture, maturity and meat quality grade, as determined by a group of experts, were not significantly different among the treatments. In conclusion, lower stocking density resulted in increased feed efficiency, daily gain, and carcass weight in Hanwoo steers. However it remains unclear whether such differences are the results of stocking density or group size, or a combination of both

  4. Effects of exposure to bodies of different sizes on perception of and satisfaction with own body size: two randomized studies.

    Science.gov (United States)

    Bould, Helen; Carnegie, Rebecca; Allward, Heather; Bacon, Emily; Lambe, Emily; Sapseid, Megan; Button, Katherine S; Lewis, Glyn; Skinner, Andy; Broome, Matthew R; Park, Rebecca; Harmer, Catherine J; Penton-Voak, Ian S; Munafò, Marcus R

    2018-05-01

    Body dissatisfaction is prevalent among women and associated with subsequent obesity and eating disorders. Exposure to images of bodies of different sizes has been suggested to change the perception of 'normal' body size in others. We tested whether exposure to different-sized (otherwise identical) bodies changes perception of own and others' body size, satisfaction with body size and amount of chocolate consumed. In Study 1, 90 18-25-year-old women with normal BMI were randomized into one of three groups to complete a 15 min two-back task using photographs of women either of 'normal weight' (Body Mass Index (BMI) 22-23 kg m -2 ), or altered to appear either under- or over-weight. Study 2 was identical except the 96 participants had high baseline body dissatisfaction and were followed up after 24 h. We also conducted a mega-analysis combining both studies. Participants rated size of others' bodies, own size, and satisfaction with size pre- and post-task. Post-task ratings were compared between groups, adjusting for pre-task ratings. Participants exposed to over- or normal-weight images subsequently perceived others' bodies as smaller, in comparison to those shown underweight bodies ( p  < 0.001). They also perceived their own bodies as smaller (Study 1, p  = 0.073; Study 2, p  = 0.018; mega-analysis, p  = 0.001), and felt more satisfied with their size (Study 1, p  = 0.046; Study 2, p  = 0.004; mega-analysis, p  = 0.006). There were no differences in chocolate consumption. This study suggests that a move towards using images of women with a BMI in the healthy range in the media may help to reduce body dissatisfaction, and the associated risk of eating disorders.

  5. Microindentation deformation of lithium dihydrogen phosphate single crystals: Microhardness measurement and indentation size effect

    Energy Technology Data Exchange (ETDEWEB)

    Iurchenko, Anton [Institute for Single Crystals, National Academy of Sciences of Ukraine, Lenin Avenue 60, 61001 Kharkiv (Ukraine); Borc, Jarosław, E-mail: j.borc@pollub.pl [Department of Applied Physics, Lublin University of Technology, ul. Nadbystrzycka 38, 20-618 Lublin (Poland); Sangwal, Keshra [Department of Applied Physics, Lublin University of Technology, ul. Nadbystrzycka 38, 20-618 Lublin (Poland); Voronov, Alexei [Institute for Single Crystals, National Academy of Sciences of Ukraine, Lenin Avenue 60, 61001 Kharkiv (Ukraine)

    2016-02-15

    The Vickers microhardness H{sub V} of the (110) and (111) as-grown faces of lithium dihydrogen phosphate (LDP) crystals was investigated as a function of applied load P. The microhardness H{sub V} of the two faces increases with load P i.e. reverse indentation size effect (reverse ISE) and the hardness of the (110) face is somewhat lower than that of the (111) face but this difference is not easily recognized for these planes due to large scatter in the data. The origin of observed ISE was analyzed using different approaches. It was found that: (1) Hays–Kendall's and Begley–Hutchinson's relations do not explain the origin of reverse ISE but Meyer's law describes the reverse ISE satisfactorily and its constants provide a link between ISE and formation of radial cracks with applied indentation load P, (2) reverse ISE is associated with tensile surface stresses, (3) despite its failure to explain reverse ISE, Begley–Hutchinson's relation is reliable to obtain load-independent hardness H{sub 0}, is 2337 MPa for LDP, and (4) the value of fracture toughness K{sub C} of LDP crystals lies between 4.7 and 12 MPa m{sup 1/2}. The load-independent hardness H{sub 0} of LDP is higher by a factor of 1.5 than that reported for undoped KDP and ADP crystals whereas its fracture toughness K{sub C} is higher by factor of about 20 than that of undoped KDP crystals. - Highlights: • Vickers indentations on the (110) and (111) faces of LDP crystals were made. • The microhardness H{sub V} was investigated as a function of applied load P. • Reverse indentation size effect was observed. • Fracture toughness K{sub C} from the radial cracks was calculated.

  6. Microindentation deformation of lithium dihydrogen phosphate single crystals: Microhardness measurement and indentation size effect

    International Nuclear Information System (INIS)

    Iurchenko, Anton; Borc, Jarosław; Sangwal, Keshra; Voronov, Alexei

    2016-01-01

    The Vickers microhardness H_V of the (110) and (111) as-grown faces of lithium dihydrogen phosphate (LDP) crystals was investigated as a function of applied load P. The microhardness H_V of the two faces increases with load P i.e. reverse indentation size effect (reverse ISE) and the hardness of the (110) face is somewhat lower than that of the (111) face but this difference is not easily recognized for these planes due to large scatter in the data. The origin of observed ISE was analyzed using different approaches. It was found that: (1) Hays–Kendall's and Begley–Hutchinson's relations do not explain the origin of reverse ISE but Meyer's law describes the reverse ISE satisfactorily and its constants provide a link between ISE and formation of radial cracks with applied indentation load P, (2) reverse ISE is associated with tensile surface stresses, (3) despite its failure to explain reverse ISE, Begley–Hutchinson's relation is reliable to obtain load-independent hardness H_0, is 2337 MPa for LDP, and (4) the value of fracture toughness K_C of LDP crystals lies between 4.7 and 12 MPa m"1"/"2. The load-independent hardness H_0 of LDP is higher by a factor of 1.5 than that reported for undoped KDP and ADP crystals whereas its fracture toughness K_C is higher by factor of about 20 than that of undoped KDP crystals. - Highlights: • Vickers indentations on the (110) and (111) faces of LDP crystals were made. • The microhardness H_V was investigated as a function of applied load P. • Reverse indentation size effect was observed. • Fracture toughness K_C from the radial cracks was calculated.

  7. Undersampling power-law size distributions: effect on the assessment of extreme natural hazards

    Science.gov (United States)

    Geist, Eric L.; Parsons, Thomas E.

    2014-01-01

    The effect of undersampling on estimating the size of extreme natural hazards from historical data is examined. Tests using synthetic catalogs indicate that the tail of an empirical size distribution sampled from a pure Pareto probability distribution can range from having one-to-several unusually large events to appearing depleted, relative to the parent distribution. Both of these effects are artifacts caused by limited catalog length. It is more difficult to diagnose the artificially depleted empirical distributions, since one expects that a pure Pareto distribution is physically limited in some way. Using maximum likelihood methods and the method of moments, we estimate the power-law exponent and the corner size parameter of tapered Pareto distributions for several natural hazard examples: tsunamis, floods, and earthquakes. Each of these examples has varying catalog lengths and measurement thresholds, relative to the largest event sizes. In many cases where there are only several orders of magnitude between the measurement threshold and the largest events, joint two-parameter estimation techniques are necessary to account for estimation dependence between the power-law scaling exponent and the corner size parameter. Results indicate that whereas the corner size parameter of a tapered Pareto distribution can be estimated, its upper confidence bound cannot be determined and the estimate itself is often unstable with time. Correspondingly, one cannot statistically reject a pure Pareto null hypothesis using natural hazard catalog data. Although physical limits to the hazard source size and by attenuation mechanisms from source to site constrain the maximum hazard size, historical data alone often cannot reliably determine the corner size parameter. Probabilistic assessments incorporating theoretical constraints on source size and propagation effects are preferred over deterministic assessments of extreme natural hazards based on historic data.

  8. Standardized Effect Size Measures for Mediation Analysis in Cluster-Randomized Trials

    Science.gov (United States)

    Stapleton, Laura M.; Pituch, Keenan A.; Dion, Eric

    2015-01-01

    This article presents 3 standardized effect size measures to use when sharing results of an analysis of mediation of treatment effects for cluster-randomized trials. The authors discuss 3 examples of mediation analysis (upper-level mediation, cross-level mediation, and cross-level mediation with a contextual effect) with demonstration of the…

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

    Science.gov (United States)

    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…

  10. On the Da Vinci size effect in tensile strengths of nanowires: A molecular dynamics study

    Science.gov (United States)

    Zhao, Ziyu; Liu, Jinxing; Soh, Ai Kah

    2018-01-01

    In recent decades, size effects caused by grain size, strain gradient, typical defects etc., have been widely investigated. Nevertheless, the dependence of tensile strength on the specimen length, addressed by Da Vinci around 500 hundred years ago, has received rather limited attention, even though it is one unavoidable question to answer if people attempt to bring materials' amazing nano-scale strengths up to macro-level. Therefore, we make efforts to study tensile behaviors of copper nanowires with a common cross-section and various lengths by employing the molecular dynamics simulations. Surprisingly, a strong size effect of Da Vinci type indeed arises. We have shown the influences of lattice orientation, temperature and prescribed notch on such a Da Vinci size effect. Two different theoretical explanations are briefly proposed for a qualitative understanding. Finally, a simple scaling rule is summarized to cover the tendencies observed.

  11. On the Da Vinci size effect in tensile strengths of nanowires: A molecular dynamics study

    Directory of Open Access Journals (Sweden)

    Ziyu Zhao

    2018-01-01

    Full Text Available In recent decades, size effects caused by grain size, strain gradient, typical defects etc., have been widely investigated. Nevertheless, the dependence of tensile strength on the specimen length, addressed by Da Vinci around 500 hundred years ago, has received rather limited attention, even though it is one unavoidable question to answer if people attempt to bring materials’ amazing nano-scale strengths up to macro-level. Therefore, we make efforts to study tensile behaviors of copper nanowires with a common cross-section and various lengths by employing the molecular dynamics simulations. Surprisingly, a strong size effect of Da Vinci type indeed arises. We have shown the influences of lattice orientation, temperature and prescribed notch on such a Da Vinci size effect. Two different theoretical explanations are briefly proposed for a qualitative understanding. Finally, a simple scaling rule is summarized to cover the tendencies observed.

  12. Notch size effects on high cycle fatigue limit stress of Udimet 720

    International Nuclear Information System (INIS)

    Ren Weiju; Nicholas, Theodore

    2003-01-01

    Notch size effects on the high cycle fatigue (HCF) limit stress of Ni-base superalloy Udimet 720 were investigated on cylindrical specimens with three notch sizes of the same stress concentration factor K t =2.74. The HCF limit stress corresponding to a life of 10 6 cycles was experimentally determined at a stress ratio of 0.1 and a frequency of 25 Hz at room temperature. The stresses were calculated using finite element analysis (FEA) and the specimens analyzed using scanning electron microscopy (SEM). Test results show that at the same K t value, notch size can slightly affect the HCF limit stress of U720 when notch root plasticity occurs. FEA and SEM results reveal that the notch size effects are influenced by a complicated combination of the stress and plastic strain fields at the notch tip, the nominal stress, and the effects of prior plastic deformation on fatigue crack initiation

  13. Size effect studies on smooth tensile specimens at room temperature and 400 oC

    International Nuclear Information System (INIS)

    Krompholz, K.; Kamber, J.; Groth, E.; Kalkhof, D.

    2000-06-01

    One of the objectives of the REVISA project (REactor Vessel Integrity in Severe Accidents) is to assess the size effect related to deformation and failure models as well as material data under quasistatic and dynamic conditions in homogeneous and non-homogeneous states of strain. For these investigations the reactor pressure vessel material 20 MnMoNi 55 was selected. It was subjected to a size effect study on smooth scaled tensile specimens of three sizes. Two strain rates (2*10 -5 /s and 10 -3 /s) and two temperatures (room temperature and 400 o C) were selected. The investigations are aimed at a support for a gradient plasticity approach to size effects. Test on the small specimens (diameters 3 and 9 mm) were performed at an electromechanical test machine, while the large specimens (diameter 30 mm) had to be tested at a servohydraulical closed loop test machine with a force capacity of 1000 kN

  14. Size effect studies on smooth tensile specimens at room temperature and 400 {sup o}C

    Energy Technology Data Exchange (ETDEWEB)

    Krompholz, K.; Kamber, J.; Groth, E.; Kalkhof, D

    2000-06-15

    One of the objectives of the REVISA project (REactor Vessel Integrity in Severe Accidents) is to assess the size effect related to deformation and failure models as well as material data under quasistatic and dynamic conditions in homogeneous and non-homogeneous states of strain. For these investigations the reactor pressure vessel material 20 MnMoNi 55 was selected. It was subjected to a size effect study on smooth scaled tensile specimens of three sizes. Two strain rates (2*10{sup -5}/s and 10{sup -3}/s) and two temperatures (room temperature and 400 {sup o}C) were selected. The investigations are aimed at a support for a gradient plasticity approach to size effects. Test on the small specimens (diameters 3 and 9 mm) were performed at an electromechanical test machine, while the large specimens (diameter 30 mm) had to be tested at a servohydraulical closed loop test machine with a force capacity of 1000 kN.

  15. The arithmetic problem size effect in children: an event-related potential study

    Directory of Open Access Journals (Sweden)

    Leen eVan Beek

    2014-09-01

    Full Text Available This study used for the first time event-related potentials (ERPs to examine the well-known arithmetic problem size effect in children. The electrophysiological correlates of this problem size effect have been well documented in adults, but such information in children is lacking. In the present study, 22 typically developing 12-year-olds were asked to solve single-digit addition problems of small (sum ≤ 10 and large problem size (sum > 10 and to speak the solution into a voice key while ERPs were recorded. Children displayed similar early and late components compared to previous adult studies on the problem size effect. There was no effect of problem size on the early components P1, N1 and P2. The peak amplitude of the N2 component showed more negative potentials on left and right anterior electrodes for large additions compared to small additions, which might reflect differences in attentional and working memory resources between large and small problems. The mean amplitude of the late positivity component (LPC, which follows the N2, was significantly larger for large than for small additions at right parieto-occipital electrodes, in line with previous adult data. The ERPs of the problem size effect during arithmetic might be a useful neural marker for future studies on fact retrieval impairments in children with mathematical difficulties.

  16. Contrast enhancement of focal hepatic lesions in CT: effect of size and histology

    International Nuclear Information System (INIS)

    Burgener, F.A.; Hamlin, D.J.

    1983-01-01

    The effect of size and histology on the contrast enhancement of hepatic lesions has been analyzed in this clinical and experimental investigation yielding the following results: (1) The attenuation values of hepatic cysts in patients increase significantly and inversely with their size after contrast enhancement when the cysts measure less than twice the CT-slice thickness. This seems to be caused by partial-volume effect. (2) Experimental tumors of identical sizes and originating from the same cell line can demonstrate different contrast-enhancement patterns. (3) Peak contrast uptake in both experimental and human tumors seems to be inversely related to their size. (4) Compared to liver, contrast washout from experimental and human tumors (presumably the extravascular space) is delayed. The delay in the contrast washout from a tumor seems to correlate with tumor size. These findings suggest that in general, it is not possible to differentiate reliably among various hepatic neoplasms on the basis of their contrast enhancement patterns for the following reasons: (1) Attenuation values of small hepatic neoplasms are distorted by partial volume effect. (2) Tumors of different histologies can demonstrate the same enhancement pattern. (3) Tumors of identical histology and size can demonstrate different enhancement patterns. (4) The enhancement pattern of a tumor changes with growth or size

  17. The effect of particle size on sorption of estrogens, androgens and progestagens in aquatic sediment

    International Nuclear Information System (INIS)

    Sangster, Jodi L.; Oke, Hugues; Zhang, Yun; Bartelt-Hunt, Shannon L.

    2015-01-01

    Highlights: • Two sediments were used to evaluate the effects of particle size on steroid sorption. • Sorption capacity did not increase with decreasing particle size for all steroids. • Particle interactions affect the distribution of steroids within the whole sediments. • Preferential sorption to fine particles was observed. - Abstract: There is growing concern about the biologic effects of steroid hormones in impacted waterways. There is increasing evidence of enhanced transport and biological effects stemming from steroid hormones associated with soils or sediments; however, there are limited studies evaluating how steroid hormone distribution between various particle sizes within whole sediments affects steroid fate. In this study, sorption of 17β-estradiol, estrone, progesterone, and testosterone was evaluated to different size fractions of two natural sediments, a silty loam and a sandy sediment, to determine the steroid sorption capacity to each fraction and distribution within the whole sediment. Sorption isotherms for all steroid hormones fit linear sorption models. Sorption capacity was influenced more by organic carbon content than particle size. Interactions between size fractions were found to affect the distribution of steroids within the whole sediments. All four steroids preferentially sorbed to the clay and colloids in the silty loam sediment at the lowest aqueous concentration (1 ng/L) and as aqueous concentration increased, the distribution of sorbed steroid was similar to the distribution by weight of each size fraction within the whole sediment. In the sandy sediment, preferential sorption to fine particles was observed.

  18. The effect of particle size on sorption of estrogens, androgens and progestagens in aquatic sediment

    Energy Technology Data Exchange (ETDEWEB)

    Sangster, Jodi L.; Oke, Hugues; Zhang, Yun; Bartelt-Hunt, Shannon L., E-mail: sbartelt2@unl.edu

    2015-12-15

    Highlights: • Two sediments were used to evaluate the effects of particle size on steroid sorption. • Sorption capacity did not increase with decreasing particle size for all steroids. • Particle interactions affect the distribution of steroids within the whole sediments. • Preferential sorption to fine particles was observed. - Abstract: There is growing concern about the biologic effects of steroid hormones in impacted waterways. There is increasing evidence of enhanced transport and biological effects stemming from steroid hormones associated with soils or sediments; however, there are limited studies evaluating how steroid hormone distribution between various particle sizes within whole sediments affects steroid fate. In this study, sorption of 17β-estradiol, estrone, progesterone, and testosterone was evaluated to different size fractions of two natural sediments, a silty loam and a sandy sediment, to determine the steroid sorption capacity to each fraction and distribution within the whole sediment. Sorption isotherms for all steroid hormones fit linear sorption models. Sorption capacity was influenced more by organic carbon content than particle size. Interactions between size fractions were found to affect the distribution of steroids within the whole sediments. All four steroids preferentially sorbed to the clay and colloids in the silty loam sediment at the lowest aqueous concentration (1 ng/L) and as aqueous concentration increased, the distribution of sorbed steroid was similar to the distribution by weight of each size fraction within the whole sediment. In the sandy sediment, preferential sorption to fine particles was observed.

  19. Study of effect of variables on particle size of telmisartan nanosuspensions using box-Behnken design.

    Science.gov (United States)

    Rao, M R P; Bajaj, A

    2014-12-01

    Telmisartan, an orally active nonpeptide angiotensin II receptor antagonist is a BCS Class II drug having aqueous solubility of 9.9 µg/ml and hence oral bioavailability of 40%. The present study involved preparation of nanosuspensions by evaporative antisolvent precipitation technique to improve the saturation solubility and dissolution rate of telmisartan. Various stabilizers such as TPGS, PVPK 30, PEG 6000 were investigated of which TPGS was found to provide maximum decrease in particle size and accord greater stability to the nanosuspensions. Box-Behnken design was used to investigate the effect of independent variables like stabilizer concentration, time and speed of stirring on particle size of nanosuspensions. Pharmacodynamic studies using Goldblatt technique were undertaken to evaluate the effect of nano-sizing on the hypotensive effect of the drug. Concentration of TPGS and speed of rotation were found to play an important role in particle size of the nanosuspensions whereas time of stirring displayed an exponential relationship with particle size. Freeze dried nanocrystals obtained from nanosuspension of least particle size were found to have increased saturation solubility of telmisartan in different dissolution media. The reconstituted nanosuspension was found to reduce both systolic and diastolic blood pressure without affecting pulse pressure and heart rate. Statistical tools can be used to identify key process and formulation parameters which play a significant role in controlling the particle size in nanosuspensions. © Georg Thieme Verlag KG Stuttgart · New York.

  20. Big bees do a better job: intraspecific size variation influences pollination effectiveness

    Directory of Open Access Journals (Sweden)

    Pat Willmer

    2014-09-01

    Full Text Available 1. Bumblebees (Bombus spp. are efficient pollinators of many flowering plants, yet the pollen deposition performance of individual bees has not been investigated. Worker bumblebees exhibit large intraspecific and intra-nest size variation, in contrast with other eusocial bees; and their size influences collection and deposition of pollen grains. 2. Laboratory studies with B. terrestris workers and Vinca minor flowers showed that pollination effectiveness PE, as measured from pollen grains deposited on stigmas in single visits (SVD, was significantly positively related to bee size; larger bees deposited more grains, while the smallest individuals, with proportionally shorter tongues, were unable to collect or deposit pollen in these flowers. Individuals did not increase their pollen deposition over time, so handling experience does not influence SVD in Vinca minor. 3. Field studies using Geranium sanguineum and Echium vulgare, and multiple visiting species, confirmed that individual size affects SVD. All bumblebee species showed positive SVD/size effects, though even the smallest individuals did deposit pollen. Apis with its limited size variation showed no such detectable effect when visiting Geranium flowers. Two abundant hoverfly species also showed size effects, particularly when feeding for nectar on Echium. 4. Mean size of foragers also varied diurnally, with larger individuals active earlier and later, so that pollination effectiveness varies through a day; flowers routinely pollinated by bees may best be served by early morning dehiscence and visits from larger individuals. 5. Thus, while there are well-documented species-level variations in pollination effectiveness, the fine-scale individual differences between foragers should also be taken into account when assessing the reproductive outputs of biotically-pollinated plants.

  1. Brain response to food cues varying in portion size is associated with individual differences in the portion size effect in children

    NARCIS (Netherlands)

    Keller, Kathleen L.; English, Laural K.; Fearnbach, S.N.; Lasschuijt, Marlou; Anderson, Kaitlin; Bermudez, Maria; Fisher, Jennifer O.; Rolls, Barbara J.; Wilson, Stephen J.

    2018-01-01

    Large portions promote intake of energy dense foods (i.e., the portion size effect–PSE), but the neurobiological drivers of this effect are not known. We tested the association between blood oxygen level dependent (BOLD) brain response to food images varied by portion size (PS) and energy density

  2. Communication: Nucleation of water on ice nanograins: Size, charge, and quantum effects

    Energy Technology Data Exchange (ETDEWEB)

    Marciante, Mathieu [Institut Lumière Matière, UMR5306 Université Lyon 1 – CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Calvo, Florent, E-mail: florent.calvo@ujf-grenoble.fr [Institut Lumière Matière, UMR5306 Université Lyon 1 – CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Laboratoire Interdisciplinaire de Physique, Rue de La Piscine, Campus Saint Martin d’Hères, 38000 Grenoble (France)

    2015-05-07

    The sticking cross sections of water molecules on cold size-selected water clusters have been simulated using classical and quantum (path-integral) molecular dynamics trajectories under realistic conditions. The integrated cross sections for charged clusters show significant size effects with comparable trends as in experiments, as well as essentially no sign effect. Vibrational delocalization, although it contributes to enlarging the geometric cross sections, leads to a counter-intuitive decrease in the dynamical cross section obtained from the trajectories. These results are interpreted based on the apparent reduction in the effective interaction between the projectile and the target owing to zero-point effects.

  3. Communication: Nucleation of water on ice nanograins: Size, charge, and quantum effects

    International Nuclear Information System (INIS)

    Marciante, Mathieu; Calvo, Florent

    2015-01-01

    The sticking cross sections of water molecules on cold size-selected water clusters have been simulated using classical and quantum (path-integral) molecular dynamics trajectories under realistic conditions. The integrated cross sections for charged clusters show significant size effects with comparable trends as in experiments, as well as essentially no sign effect. Vibrational delocalization, although it contributes to enlarging the geometric cross sections, leads to a counter-intuitive decrease in the dynamical cross section obtained from the trajectories. These results are interpreted based on the apparent reduction in the effective interaction between the projectile and the target owing to zero-point effects

  4. [Geography of effective size of rural populations of Northern Eurasia. Geographic correlation between effective size and level of heterozygosity of populations].

    Science.gov (United States)

    Evsiukov, A N; Zhukova, O V; Sheremet'eva, V A; Shneĭder, Iu V; Rychkov, Iu G

    1996-11-01

    A significant geographical correlation (r = 0.719) was found between the logarithm of effective size (InNe) and heterozygosity level (H) in populations under the assumption of the Hardy-Weinberg equilibrium. The area of highest positive correlation was positioned meridionally between the Ob and Yenisei rivers, from the Arctic coast of Taimyr Peninsula to eastern Sayans and the southern Cis-Baikal region, i.e., in the same region where the highest distribution density of mean Ne values was found. Two additional areas of high correlations were found on the northern Black Sea coast and in the lower Lena river region. Analysis and mapping of correlation ratios eta H/lnNe2 and eta lnNe/H2 revealed that effective size substantially influenced heterozygosity level (as could be expected in the case of an intense gene drift), and heterozygosity level influenced effective size to the same extent. The latter relationship indicated an intense adaptation, and changes in diversity of the gene pool caused substantial demographic changes. However, this might be accounted for by direct gene migration into a population prevailing over reverse migration, i.e., mechanical population growth prevailing over natural growth.

  5. The Effects of Metal on Size Specific Dose Estimation (SSDE) in CT: A Phantom Study

    Science.gov (United States)

    Alsanea, Maram M.

    Over the past number of years there has been a significant increase in the awareness of radiation dose from use of computed tomography (CT). Efforts have been made to reduce radiation dose from CT and to better quantify dose being delivered. However, unfortunately, these dose metrics such as CTDI vol are not a specific patient dose. In 2011, the size-specific dose estimation (SSDE) was introduced by AAPM TG-204 which accounts for the physical size of the patient. However, the approach presented in TG-204 ignores the importance of the attenuation differences in the body. In 2014, a newer methodology that accounted for tissue attenuation was introduced by the AAPM TG-220 based on the concept of water equivalent diameter, Dw. One of the limitation of TG-220 is that there is no estimation of the dose while highly attenuating objects such as metal is present in the body. The purpose of this research is to evaluate the accuracy of size-specific dose estimates in CT in the presence of simulated metal prostheses using a conventional PMMA CTDI phantom at different phantom diameter (body and head) and beam energy. Titanium, Cobalt- chromium and stainless steel alloys rods were used in the study. Two approaches were used as introduced by AAPM TG-204 and 220 utilizing the effective diameter and the Dw calculations. From these calculations, conversion factors have been derived that could be applied to the measured CTDIvol to convert it to specific patient dose, or size specific dose estimate, (SSDE). Radiation dose in tissue (f-factor = 0.94) was measured at various chamber positions with the presence of metal. Following, an average weighted tissue dose (AWTD) was calculated in a manner similar to the weighted CTDI (CTDIw). In general, for the 32 cm body phantom SSDE220 provided more accurate estimates of AWTD than did SSDE204. For smaller patient size, represented by the 16 cm head phantom, the SSDE204 was a more accurate estimate of AWTD that that of SSDE220. However, as the

  6. Effect of freeze-thaw cycling on grain size of biochar.

    Science.gov (United States)

    Liu, Zuolin; Dugan, Brandon; Masiello, Caroline A; Wahab, Leila M; Gonnermann, Helge M; Nittrouer, Jeffrey A

    2018-01-01

    Biochar may improve soil hydrology by altering soil porosity, density, hydraulic conductivity, and water-holding capacity. These properties are associated with the grain size distributions of both soil and biochar, and therefore may change as biochar weathers. Here we report how freeze-thaw (F-T) cycling impacts the grain size of pine, mesquite, miscanthus, and sewage waste biochars under two drainage conditions: undrained (all biochars) and a gravity-drained experiment (mesquite biochar only). In the undrained experiment plant biochars showed a decrease in median grain size and a change in grain-size distribution consistent with the flaking off of thin layers from the biochar surface. Biochar grain size distribution changed from unimodal to bimodal, with lower peaks and wider distributions. For plant biochars the median grain size decreased by up to 45.8% and the grain aspect ratio increased by up to 22.4% after 20 F-T cycles. F-T cycling did not change the grain size or aspect ratio of sewage waste biochar. We also observed changes in the skeletal density of biochars (maximum increase of 1.3%), envelope density (maximum decrease of 12.2%), and intraporosity (porosity inside particles, maximum increase of 3.2%). In the drained experiment, mesquite biochar exhibited a decrease of median grain size (up to 4.2%) and no change of aspect ratio after 10 F-T cycles. We also document a positive relationship between grain size decrease and initial water content, suggesting that, biochar properties that increase water content, like high intraporosity and pore connectivity large intrapores, and hydrophilicity, combined with undrained conditions and frequent F-T cycles may increase biochar breakdown. The observed changes in biochar particle size and shape can be expected to alter hydrologic properties, and thus may impact both plant growth and the hydrologic cycle.

  7. The effect of precursor powder size on the microstructure and integranular properties of Bi2223 superconductors

    Directory of Open Access Journals (Sweden)

    I. Abdolhosseini

    2006-09-01

    Full Text Available  We have studied the effect of precursor powder size on the microstructure and intergranular behavior of polycrystalline Bi2223 superconductors using the XRD, SEM, electrical resistivity and AC susceptibility techniques. Polycrystalline Bi2223 superconductors were prepared from the powders with different milling times. The XRD results show that by decreasing the precursor powder size the Bi2223 phase fraction increases. It was found that the grain size and grain connectivity improved by decreasing the precursor powder size. Analysis of the temperature dependence of the AC susceptibility near the transition temperature (Tc has been done employing Beans critical state model. The observed variation of intergranular critical current densities (Jc with temperature indicates that the decreasing of precursor powder size in the Bi2223 system cases an increase in the intergranular critical current density.

  8. Effects of patch size on feeding associations in muriquis (Brachyteles arachnoides).

    Science.gov (United States)

    Strier, K B

    1989-01-01

    Data were collected on one group of muriquis, or woolly spider monkeys (Brachyteles arachnoides) during a 14-month study at Fazenda Montes Claros, Minas Gerais, Brazil to examine the effects of food patch size on muriqui feeding associations. Muriqui food patches were larger than expected from the availability of patch sizes in the forest; fruit patches were significantly larger than leaf patches. Feeding aggregate size, the maximum number of simultaneous occupants, and patch occupancy time were positively related to the size of fruit patches. However, a greater number of individuals fed at leaf sources than expected from the size of these patches. Adult females tended to feed alone in patches more often than males, whereas males tended to feed in single-sexed groups more often than females. Yet in neither case were these differences statistically significant.

  9. Automatic analog IC sizing and optimization constrained with PVT corners and layout effects

    CERN Document Server

    Lourenço, Nuno; Horta, Nuno

    2017-01-01

    This book introduces readers to a variety of tools for automatic analog integrated circuit (IC) sizing and optimization. The authors provide a historical perspective on the early methods proposed to tackle automatic analog circuit sizing, with emphasis on the methodologies to size and optimize the circuit, and on the methodologies to estimate the circuit’s performance. The discussion also includes robust circuit design and optimization and the most recent advances in layout-aware analog sizing approaches. The authors describe a methodology for an automatic flow for analog IC design, including details of the inputs and interfaces, multi-objective optimization techniques, and the enhancements made in the base implementation by using machine leaning techniques. The Gradient model is discussed in detail, along with the methods to include layout effects in the circuit sizing. The concepts and algorithms of all the modules are thoroughly described, enabling readers to reproduce the methodologies, improve the qual...

  10. Nonlocal Poisson-Fermi double-layer models: Effects of nonuniform ion sizes on double-layer structure

    Science.gov (United States)

    Xie, Dexuan; Jiang, Yi

    2018-05-01

    This paper reports a nonuniform ionic size nonlocal Poisson-Fermi double-layer model (nuNPF) and a uniform ionic size nonlocal Poisson-Fermi double-layer model (uNPF) for an electrolyte mixture of multiple ionic species, variable voltages on electrodes, and variable induced charges on boundary segments. The finite element solvers of nuNPF and uNPF are developed and applied to typical double-layer tests defined on a rectangular box, a hollow sphere, and a hollow rectangle with a charged post. Numerical results show that nuNPF can significantly improve the quality of the ionic concentrations and electric fields generated from uNPF, implying that the effect of nonuniform ion sizes is a key consideration in modeling the double-layer structure.

  11. Effect of laser energy on the SPR and size of silver nanoparticles synthesized by pulsed laser ablation in distilled water

    Science.gov (United States)

    Baruah, Prahlad K.; Sharma, Ashwini K.; Khare, Alika

    2018-04-01

    The effect of incident laser energy on the surface plasmon resonance (SPR) and size of silver nanoparticles synthesized via pulsed laser ablation of silver immersed in distilled water is reported in this paper. The broadening in the plasmonic bandwidth of the synthesized nanoparticles with the increase in the laser energy incident onto the silver target indicates the reduction in size of the nanoparticles. This is confirmed by the transmission electron microscope (TEM) images which show a decrease in the average particle size of the nanoparticles from approximately 15 to 10 nm with the increase in incident laser energy from 30 to 70 mJ, respectively. The structural features as revealed by the selected area electron diffraction and ultra-high resolution TEM studies confirmed the formation of both silver as well as silver oxide nanoparticles.

  12. Effective porosity and pore-throat sizes of Conasauga Group mudrock: Application, test and evaluation of petrophysical techniques

    International Nuclear Information System (INIS)

    Dorsch, J.; Katsube, T.J.; Sanford, W.E.; Univ. of Tennessee, Knoxville, TN; Dugan, B.E.; Tourkow, L.M.

    1996-04-01

    Effective porosity (specifically referring to the interconnected pore space) was recently recognized as being essential in determining the effectiveness and extent of matrix diffusion as a transport mechanism within fractured low-permeability rock formations. The research presented in this report was performed to test the applicability of several petrophysical techniques for the determination of effective porosity of fine-grained siliciclastic rocks. In addition, the aim was to gather quantitative data on the effective porosity of Conasauga Group mudrock from the Oak Ridge Reservation (ORR). The quantitative data reported here include not only effective porosities based on diverse measurement techniques, but also data on the sizes of pore throats and their distribution, and specimen bulk and grain densities. The petrophysical techniques employed include the immersion-saturation method, mercury and helium porosimetry, and the radial diffusion-cell method

  13. Excitonic effects and related properties in semiconductor nanostructures: roles of size and dimensionality

    Science.gov (United States)

    Wu, Shudong; Cheng, Liwen; Wang, Qiang

    2017-08-01

    The size- and dimensionality-dependence of excitonic effects and related properties in semiconductor nanostructures are theoretically studied in detail within the effective-mass approximation. When nanostructure sizes become smaller than the bulk exciton Bohr radius, excitonic effects are significantly enhanced with reducing size or dimensionality. This is as a result of quantum confinement in more directions leading to larger exciton binding energies and normalized exciton oscillator strengths. These excitonic effects originate from electron-hole Coulombic interactions, which strongly enhance the oscillator strength between the electron and hole. It is also established that the universal scaling of exciton binding energy versus the inverse of the exciton Bohr radius follows a linear scaling law. Herein, we propose a stretched exponential law for the size scaling of optical gap, which is in good agreement with the calculated data. Due to differences in the confinement dimensionality, the radiative lifetime of low-dimensional excitons becomes shorter than that of bulk excitons. The size dependence of the exciton radiative lifetimes is in good agreement with available experimental data. This strongly enhanced electron-hole exchange interaction is expected in low-dimensional structures due to enriched excitonic effects. The main difference in nanostructures compared to the bulk can be interpreted in terms of the enhanced excitonic effects induced by exciton localization. The enhanced excitonic effects are expected to be of importance in developing stable and high-efficiency nanoscale excitonic optoelectronic devices.

  14. Orientation dependent size effects in single crystalline anisotropic nanoplates with regard to surface energy

    International Nuclear Information System (INIS)

    Assadi, Abbas; Salehi, Manouchehr; Akhlaghi, Mehdi

    2015-01-01

    In this work, size dependent behavior of single crystalline normal and auxetic anisotropic nanoplates is discussed with consideration of material surface stresses via a generalized model. Bending of pressurized nanoplates and their fundamental resonant frequency are discussed for different crystallographic directions and anisotropy degrees. It is explained that the orientation effects are considerable when the nanoplates' edges are pinned but for clamped nanoplates, the anisotropy effect may be ignored. The size effects are the highest when the simply supported nanoplates are parallel to [110] direction but as the anisotropy gets higher, the size effects are reduced. The orientation effect is also discussed for possibility of self-instability occurrence in nanoplates. The results in simpler cases are compared with previous experiments for nanowires but with a correction factor. There are still some open questions for future studies. - Highlights: • Size effects in single crystalline anisotropic nanoplates are discussed. • A generalized model is established containing some physical assumptions. • Orientation dependent size effects due to material anisotropy are explained. • Bending, instability and frequencies are studied at normal/auxetic domain

  15. Investigating size effects of complex nanostructures through Young-Laplace equation and finite element analysis

    International Nuclear Information System (INIS)

    Lu, Dingjie; Xie, Yi Min; Huang, Xiaodong; Zhou, Shiwei; Li, Qing

    2015-01-01

    Analytical studies on the size effects of a simply-shaped beam fixed at both ends have successfully explained the sudden changes of effective Young's modulus as its diameter decreases below 100 nm. Yet they are invalid for complex nanostructures ubiquitously existing in nature. In accordance with a generalized Young-Laplace equation, one of the representative size effects is transferred to non-uniformly distributed pressure against an external surface due to the imbalance of inward and outward loads. Because the magnitude of pressure depends on the principal curvatures, iterative steps have to be adopted to gradually stabilize the structure in finite element analysis. Computational results are in good agreement with both experiment data and theoretical prediction. Furthermore, the investigation on strengthened and softened Young's modulus for two complex nanostructures demonstrates that the proposed computational method provides a general and effective approach to analyze the size effects for nanostructures in arbitrary shape

  16. Adding effect sizes to a systematic review on interventions for promoting physical activity among European teenagers

    Directory of Open Access Journals (Sweden)

    Crutzen Rik

    2010-04-01

    Full Text Available Abstract This commentary adds effect sizes to the recently published systematic review by De Meester and colleagues and provides a more detailed insight into the effectiveness of interventions to promote physical activity among European teenagers. The main findings based on this evidence were: (1 school-based interventions generally lead to short term improvement in physical activity levels, but there were large differences between interventions with regard to effect sizes; (2 a multi-component approach (including environmental components generally resulted in larger effect sizes, thereby providing evidence for the assumption that a multi-component approach should produce synergistic results; and (3 if an intervention aimed to affect more health behaviours besides physical activity, then the intervention appeared to be less effective in favour of physical activity.

  17. A new look at grain size and load effects in the hardness of ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Krell, A. [Fraunhofer-Institut fuer Keramische Technologien und Sinterwerkstoffe (IKTS), Dresden (Germany)

    1998-05-01

    A simple model describes the load effect (size effect) in the hardness, assuming an increasing microplastic deformability, when the further extension of the plastic zone growth and multiplication of pre-existing elements of plasticity are more effective than the generation of new dislocations or twins in the virgin material around the indentation site. The model explains experiments with sintered alumina which indicate a reduced load effect in increasingly fine-grained microstructures due to a grain size effect that is more pronounced at higher testing loads (larger indents) than in the microhardness range. A large difference between the hardness of plastically deformed volumes in single crystals and in polycrystalline microstructures consisting of grains with the same size, respectively, reveals a substantial contribution of the grain boundaries to plastic deformation at the indentation site even at room temperature and even for coarser microstructures. (orig.) 18 refs.

  18. Tunable separations based on a molecular size effect for biomolecules by poly(ethylene glycol) gel-based capillary electrophoresis.

    Science.gov (United States)

    Kubo, Takuya; Nishimura, Naoki; Furuta, Hayato; Kubota, Kei; Naito, Toyohiro; Otsuka, Koji

    2017-11-10

    We report novel capillary gel electrophoresis (CGE) with poly(ethylene glycol) (PEG)-based hydrogels for the effective separations of biomolecules containing sugars and DNAs based on a molecular size effect. The gel capillaries were prepared in a fused silica capillary modified with 3-(trimethoxysilyl)propylmethacrylate using a variety of the PEG-based hydrogels. After the fundamental evaluations in CGE regarding the separation based on the molecular size effect depending on the crosslinking density, the optimized capillary provided the efficient separation of glucose ladder (G1 to G20). In addition, another capillary showed the successful separation of DNA ladder in the range of 10-1100 base pair, which is superior to an authentic acrylamide-based gel capillary. For both glucose and DNA ladders, the separation ranges against the molecular size were simply controllable by alteration of the concentration and/or units of ethylene oxide in the PEG-based crosslinker. Finally, we demonstrated the separations of real samples, which included sugars carved out from monoclonal antibodies, mAbs, and then the efficient separations based on the molecular size effect were achieved. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Effect of microcavitary alginate hydrogel with different pore sizes on chondrocyte culture for cartilage tissue engineering

    International Nuclear Information System (INIS)

    Zeng, Lei; Yao, Yongchang; Wang, Dong-an; Chen, Xiaofeng

    2014-01-01

    In our previous work, a novel microcavitary hydrogel was proven to be effective for proliferation of chondrocytes and maintenance of chondrocytic phenotype. In present work, we further investigated whether the size of microcavity would affect the growth and the function of chondrocytes. By changing the stirring rate, gelatin microspheres in different sizes including small size (80–120 μm), middle size (150–200 μm) and large size (250–300 μm) were prepared. And then porcine chondrocytes were encapsulated into alginate hydrogel with various sizes of gelatin microspheres. Cell Counting Kit-8 (CCK-8), Live/dead staining and real-time PCR were used to analyze the effect of the pore size on cell proliferation and expression of specific chondrocytic genes. According to all the data, cells cultivated in microcavitary hydrogel, especially in small size, had preferable abilities of proliferation and higher expression of cartilaginous markers including type II collagen, aggrecan and cartilage oligomeric matrix protein (COMP). Furthermore, it was shown by western blot assay that the culture of chondrocytes in microcavitary hydrogel could improve the proliferation of cells potentially by inducing the Erk1/2-MAPK pathway. Taken together, this study demonstrated that chondrocytes favored microcavitary alginate hydrogel with pore size within the range of 80–120 μm for better growth and ECM synthesis, in which Erk1/2 pathway was involved. This culture system would be promising for cartilage tissue engineering. - Highlights: • A novel model with microcavitary structure was set up to study the interaction between cells and materials. • Microcavitary alginate hydrogel could enhance the proliferation of chondrocytes and promote the expression of cartilaginous genes as compared with plain alginate hydrogel. • Cells in microcavitary alginate hydrogel with pore size within the range of 80–120 μm were capable of better growth and ECM synthesis

  20. Effect of microcavitary alginate hydrogel with different pore sizes on chondrocyte culture for cartilage tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Lei; Yao, Yongchang [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China); Wang, Dong-an, E-mail: DAWang@ntu.edu.sg [National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China); Division of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457 (Singapore); Chen, Xiaofeng, E-mail: chenxf@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China)

    2014-01-01

    In our previous work, a novel microcavitary hydrogel was proven to be effective for proliferation of chondrocytes and maintenance of chondrocytic phenotype. In present work, we further investigated whether the size of microcavity would affect the growth and the function of chondrocytes. By changing the stirring rate, gelatin microspheres in different sizes including small size (80–120 μm), middle size (150–200 μm) and large size (250–300 μm) were prepared. And then porcine chondrocytes were encapsulated into alginate hydrogel with various sizes of gelatin microspheres. Cell Counting Kit-8 (CCK-8), Live/dead staining and real-time PCR were used to analyze the effect of the pore size on cell proliferation and expression of specific chondrocytic genes. According to all the data, cells cultivated in microcavitary hydrogel, especially in small size, had preferable abilities of proliferation and higher expression of cartilaginous markers including type II collagen, aggrecan and cartilage oligomeric matrix protein (COMP). Furthermore, it was shown by western blot assay that the culture of chondrocytes in microcavitary hydrogel could improve the proliferation of cells potentially by inducing the Erk1/2-MAPK pathway. Taken together, this study demonstrated that chondrocytes favored microcavitary alginate hydrogel with pore size within the range of 80–120 μm for better growth and ECM synthesis, in which Erk1/2 pathway was involved. This culture system would be promising for cartilage tissue engineering. - Highlights: • A novel model with microcavitary structure was set up to study the interaction between cells and materials. • Microcavitary alginate hydrogel could enhance the proliferation of chondrocytes and promote the expression of cartilaginous genes as compared with plain alginate hydrogel. • Cells in microcavitary alginate hydrogel with pore size within the range of 80–120 μm were capable of better growth and ECM synthesis.

  1. Size Constancy Is Preserved but Afterimages Are Prolonged in Typical Individuals with Higher Degrees of Self-Reported Autistic Traits

    Science.gov (United States)

    Sperandio, Irene; Unwin, Katy L.; Landry, Oriane; Chouinard, Philippe A.

    2017-01-01

    Deficits in perceptual constancies from early infancy have been proposed to contribute to autism and exacerbate its symptoms (Hellendoorn et al., "Frontiers in Psychology" 6:1-16, 2015). Here, we examined size constancy in adults from the general population (N = 106) with different levels of self-reported autistic traits using an…

  2. Sizes and shapes of short-lived nuclei via laser spectroscopy. Progress report, May 1, 1980-January 31, 1981

    International Nuclear Information System (INIS)

    Lewis, D.A.

    1981-02-01

    The first stage of the program to study the sizes and shapes of short-lived nuclei through their atomic hyperfine structure is to develop a movable laser spectroscopy system. This system is now almost complete and is described in this report along with plans for measurements at Argonne National Laboratory and Brookhaven National Laboratory

  3. NEAMS FPL M2 Milestone Report: Development of a UO₂ Grain Size Model using Multicale Modeling and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Tonks, Michael R [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Yongfeng [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bai, Xianming [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-06-01

    This report summarizes development work funded by the Nuclear Energy Advanced Modeling Simulation program's Fuels Product Line (FPL) to develop a mechanistic model for the average grain size in UO₂ fuel. The model is developed using a multiscale modeling and simulation approach involving atomistic simulations, as well as mesoscale simulations using INL's MARMOT code.

  4. Revealing life-history traits by contrasting genetic estimations with predictions of effective population size.

    Science.gov (United States)

    Greenbaum, Gili; Renan, Sharon; Templeton, Alan R; Bouskila, Amos; Saltz, David; Rubenstein, Daniel I; Bar-David, Shirli

    2017-12-22

    Effective population size, a central concept in conservation biology, is now routinely estimated from genetic surveys and can also be theoretically predicted from demographic, life-history, and mating-system data. By evaluating the consistency of theoretical predictions with empirically estimated effective size, insights can be gained regarding life-history characteristics and the relative impact of different life-history traits on genetic drift. These insights can be used to design and inform management strategies aimed at increasing effective population size. We demonstrated this approach by addressing the conservation of a reintroduced population of Asiatic wild ass (Equus hemionus). We estimated the variance effective size (N ev ) from genetic data (N ev =24.3) and formulated predictions for the impacts on N ev of demography, polygyny, female variance in lifetime reproductive success (RS), and heritability of female RS. By contrasting the genetic estimation with theoretical predictions, we found that polygyny was the strongest factor affecting genetic drift because only when accounting for polygyny were predictions consistent with the genetically measured N ev . The comparison of effective-size estimation and predictions indicated that 10.6% of the males mated per generation when heritability of female RS was unaccounted for (polygyny responsible for 81% decrease in N ev ) and 19.5% mated when female RS was accounted for (polygyny responsible for 67% decrease in N ev ). Heritability of female RS also affected N ev ; hf2=0.91 (heritability responsible for 41% decrease in N ev ). The low effective size is of concern, and we suggest that management actions focus on factors identified as strongly affecting Nev, namely, increasing the availability of artificial water sources to increase number of dominant males contributing to the gene pool. This approach, evaluating life-history hypotheses in light of their impact on effective population size, and contrasting

  5. THE EFFECTS OF GRAIN SIZE AND TEMPERATURE DISTRIBUTIONS ON THE FORMATION OF INTERSTELLAR ICE MANTLES

    Energy Technology Data Exchange (ETDEWEB)

    Pauly, Tyler; Garrod, Robin T., E-mail: tap74@cornell.edu [Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14853-6801 (United States)

    2016-02-01

    Computational models of interstellar gas-grain chemistry have historically adopted a single dust-grain size of 0.1 micron, assumed to be representative of the size distribution present in the interstellar medium. Here, we investigate the effects of a broad grain-size distribution on the chemistry of dust-grain surfaces and the subsequent build-up of molecular ices on the grains, using a three-phase gas-grain chemical model of a quiescent dark cloud. We include an explicit treatment of the grain temperatures, governed both by the visual extinction of the cloud and the size of each individual grain-size population. We find that the temperature difference plays a significant role in determining the total bulk ice composition across the grain-size distribution, while the effects of geometrical differences between size populations appear marginal. We also consider collapse from a diffuse to a dark cloud, allowing dust temperatures to fall. Under the initial diffuse conditions, small grains are too warm to promote grain-mantle build-up, with most ices forming on the mid-sized grains. As collapse proceeds, the more abundant, smallest grains cool and become the dominant ice carriers; the large population of small grains means that this ice is distributed across many grains, with perhaps no more than 40 monolayers of ice each (versus several hundred assuming a single grain size). This effect may be important for the subsequent processing and desorption of the ice during the hot-core phase of star formation, exposing a significant proportion of the ice to the gas phase, increasing the importance of ice-surface chemistry and surface–gas interactions.

  6. The Effects of Grain Size and Temperature Distributions on the Formation of Interstellar Ice Mantles

    Science.gov (United States)

    Pauly, Tyler; Garrod, Robin T.

    2016-02-01

    Computational models of interstellar gas-grain chemistry have historically adopted a single dust-grain size of 0.1 micron, assumed to be representative of the size distribution present in the interstellar medium. Here, we investigate the effects of a broad grain-size distribution on the chemistry of dust-grain surfaces and the subsequent build-up of molecular ices on the grains, using a three-phase gas-grain chemical model of a quiescent dark cloud. We include an explicit treatment of the grain temperatures, governed both by the visual extinction of the cloud and the size of each individual grain-size population. We find that the temperature difference plays a significant role in determining the total bulk ice composition across the grain-size distribution, while the effects of geometrical differences between size populations appear marginal. We also consider collapse from a diffuse to a dark cloud, allowing dust temperatures to fall. Under the initial diffuse conditions, small grains are too warm to promote grain-mantle build-up, with most ices forming on the mid-sized grains. As collapse proceeds, the more abundant, smallest grains cool and become the dominant ice carriers; the large population of small grains means that this ice is distributed across many grains, with perhaps no more than 40 monolayers of ice each (versus several hundred assuming a single grain size). This effect may be important for the subsequent processing and desorption of the ice during the hot-core phase of star formation, exposing a significant proportion of the ice to the gas phase, increasing the importance of ice-surface chemistry and surface-gas interactions.

  7. Environment-effect reporting. Chapter 6

    International Nuclear Information System (INIS)

    Hermens, P.A.H.

    1989-01-01

    Environment-effect reporting is a tool in the resolution of one or more government bodies about activities which may have important disadvantageous impacts upon the environment. This chapter gives a treatment of environment-effect reporting as a process consisting of the preparation, draw-up, judgement and use of an environment-effect report (MER), followed by an evaluation. The contentsof an environment-effect report are indicated. The role of environment-effect reporting in relation with other procedures is discussed. Some experience with the application of environment-effect reporting is presented and a number of experiences in the application are discussed. (H.W.). 5 refs.; 3 figs.; 3 tabs

  8. Determining the effect of grain size and maximum induction upon coercive field of electrical steels

    Science.gov (United States)

    Landgraf, Fernando José Gomes; da Silveira, João Ricardo Filipini; Rodrigues-Jr., Daniel

    2011-10-01

    Although theoretical models have already been proposed, experimental data is still lacking to quantify the influence of grain size upon coercivity of electrical steels. Some authors consider a linear inverse proportionality, while others suggest a square root inverse proportionality. Results also differ with regard to the slope of the reciprocal of grain size-coercive field relation for a given material. This paper discusses two aspects of the problem: the maximum induction used for determining coercive force and the possible effect of lurking variables such as the grain size distribution breadth and crystallographic texture. Electrical steel sheets containing 0.7% Si, 0.3% Al and 24 ppm C were cold-rolled and annealed in order to produce different grain sizes (ranging from 20 to 150 μm). Coercive field was measured along the rolling direction and found to depend linearly on reciprocal of grain size with a slope of approximately 0.9 (A/m)mm at 1.0 T induction. A general relation for coercive field as a function of grain size and maximum induction was established, yielding an average absolute error below 4%. Through measurement of B50 and image analysis of micrographs, the effects of crystallographic texture and grain size distribution breadth were qualitatively discussed.

  9. Dissociating object-based from egocentric transformations in mental body rotation: effect of stimuli size.

    Science.gov (United States)

    Habacha, Hamdi; Moreau, David; Jarraya, Mohamed; Lejeune-Poutrain, Laure; Molinaro, Corinne

    2018-01-01

    The effect of stimuli size on the mental rotation of abstract objects has been extensively investigated, yet its effect on the mental rotation of bodily stimuli remains largely unexplored. Depending on the experimental design, mentally rotating bodily stimuli can elicit object-based transformations, relying mainly on visual processes, or egocentric transformations, which typically involve embodied motor processes. The present study included two mental body rotation tasks requiring either a same-different or a laterality judgment, designed to elicit object-based or egocentric transformations, respectively. Our findings revealed shorter response times for large-sized stimuli than for small-sized stimuli only for greater angular disparities, suggesting that the more unfamiliar the orientations of the bodily stimuli, the more stimuli size affected mental processing. Importantly, when comparing size transformation times, results revealed different patterns of size transformation times as a function of angular disparity between object-based and egocentric transformations. This indicates that mental size transformation and mental rotation proceed differently depending on the mental rotation strategy used. These findings are discussed with respect to the different spatial manipulations involved during object-based and egocentric transformations.

  10. Effects of crystal size on the mechanical properties of a lithium disilicate glass-ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Li, D. [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, 28 West Xianning Road, Xi’an 710049 (China); Guo, J.W.; Wang, X.S; Zhang, S.F. [State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, 145 West Changle Road, Xi’an 710032 (China); He, L., E-mail: helin@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, 28 West Xianning Road, Xi’an 710049 (China)

    2016-07-04

    Crystal size of lithium disilicate (LD) phase in a LD glass-ceramic was changed by thermally controlled crystallization of a precursory LD glass at different temperatures. Effects of the crystal size on the mechanical properties of the glass-ceramic were investigated. It was found that the flexural strength presented a hump-like variation trend with increasing the crystal size, the hardness monotonously decreased at the same time. It was further confirmed that micro residual compressive stresses existed inside the LD crystals due to the thermal expansion mismatch between the glass matrix and the crystalline phase. The levels of the residual stresses increased with increasing the crystal size. The crystal size performed dual effects on the flexural strength of the glass-ceramic: an “interlocking effect” caused by larger-sized LD crystals and a “micro residual stress effect” related to the balancing tensile stresses in the glass matrix. Higher residual tensile stresses in the glass matrix induced by larger-sized LD crystals would counteract the “interlocking effect” of the crystals, causing the strength degradation. The hardness of the glass-ceramic was mainly controlled by the “micro residual stress effect”.

  11. Interactive effects of warming, eutrophication and size structure: impacts on biodiversity and food-web structure.

    Science.gov (United States)

    Binzer, Amrei; Guill, Christian; Rall, Björn C; Brose, Ulrich

    2016-01-01

    Warming and eutrophication are two of the most important global change stressors for natural ecosystems, but their interaction is poorly understood. We used a dynamic model of complex, size-structured food webs to assess interactive effects on diversity and network structure. We found antagonistic impacts: Warming increases diversity in eutrophic systems and decreases it in oligotrophic systems. These effects interact with the community size structure: Communities of similarly sized species such as parasitoid-host systems are stabilized by warming and destabilized by eutrophication, whereas the diversity of size-structured predator-prey networks decreases strongly with warming, but decreases only weakly with eutrophication. Nonrandom extinction risks for generalists and specialists lead to higher connectance in networks without size structure and lower connectance in size-structured communities. Overall, our results unravel interactive impacts of warming and eutrophication and suggest that size structure may serve as an important proxy for predicting the community sensitivity to these global change stressors. © 2015 John Wiley & Sons Ltd.

  12. The size effect of searching window for measuring wavefront of laser beam

    International Nuclear Information System (INIS)

    Park, Seung Kyu; Baik, Sung Hoon; Lim, Chang Hwan; Kim, Jung Cheol; Yi, Seung Jun; Ra, Sung Woong

    2003-01-01

    We investigated the size effect of the searching window for measuring of a laser beam using a Shack-Hartmann sensor. The shapes of spot images on an acquired wavefront image by using a Shack-Hartmann sensor are usually imbalanced. Also, the distributed intensity pattern of each spot image is varied according to successively acquired wavefront image. We studied on the optimized size of searching window to get wavefront with high measurement resolution. We experimented on the various size effect of searching window on an acquired wavefront image to get fine wavefront information using a Shack-Hartmann sensor. As the experimental results, we proposed the optimum size of searching window to measure improved wavefront.

  13. Quantitative study of bundle size effect on thermal conductivity of single-walled carbon nanotubes

    Science.gov (United States)

    Feng, Ya; Inoue, Taiki; An, Hua; Xiang, Rong; Chiashi, Shohei; Maruyama, Shigeo

    2018-05-01

    Compared with isolated single-walled carbon nanotubes (SWNTs), thermal conductivity is greatly impeded in SWNT bundles; however, the measurement of the bundle size effect is difficult. In this study, the number of SWNTs in a bundle was determined based on the transferred horizontally aligned SWNTs on a suspended micro-thermometer to quantitatively study the effect of the bundle size on thermal conductivity. Increasing the bundle size significantly degraded the thermal conductivity. For isolated SWNTs, thermal conductivity was approximately 5000 ± 1000 W m-1 K-1 at room temperature, three times larger than that of the four-SWNT bundle. The logarithmical deterioration of thermal conductivity resulting from the increased bundle size can be attributed to the increased scattering rate with neighboring SWNTs based on the kinetic theory.

  14. The Effect of Body Size in Mercury Accumulation Biokinetic of Cockle Shell (Anadara Granosa)

    International Nuclear Information System (INIS)

    Wahyu Retno Prihatiningsih

    2007-01-01

    Accumulation of mercury biokinetic in cockle shell (Anadara granosa) through water pathway has been investigated under laboratory condition. The objective of research is to find the effect of body size in mercury biokinetic of Anadara granosa and to find bioindicator based on biokinetic parameter. The research shows that body size of Anadara granosa give an effect to concentration factor and could barrier mercury contaminant. Concentration factor for size 1.9, 2.5 and 3.9 cm of biota moving high and reach steady state condition after 24 days. Concentration factor of Anadara granosa in size 1.9, 2.5 and 3.9 is 0.1476, 0.1645 and 0.2573 day. Based on mechanism of mercury biokinetic process, it was proof that Anadara granosa is an ideal invertebrate for bioindicator. (author)

  15. Use of care management practices in small- and medium-sized physician groups: do public reporting of physician quality and financial incentives matter?

    Science.gov (United States)

    Alexander, Jeffrey A; Maeng, Daniel; Casalino, Lawrence P; Rittenhouse, Diane

    2013-04-01

    To examine the effect of public reporting (PR) and financial incentives tied to quality performance on the use of care management practices (CMPs) among small- and medium-sized physician groups. Survey data from The National Study of Small and Medium-sized Physician Practices were used. Primary data collection was also conducted to assess community-level PR activities. The final sample included 643 practices engaged in quality reporting; about half of these practices were subject to PR. We used a treatment effects model. The instrumental variables were the community-level variables that capture the level of PR activity in each community in which the practices operate. (1) PR is associated with increased use of CMPs, but the estimate is not statistically significant; (2) financial incentives are associated with greater use of CMPs; (3) practices' awareness/sensitivity to quality reports is positively related to their use of CMPs; and (4) combined PR and financial incentives jointly affect CMP use to a greater degree than either of these factors alone. Small- to medium-sized practices appear to respond to PR and financial incentives by greater use of CMPs. Future research needs to investigate the appropriate mix and type of incentive arrangements and quality reporting. © Health Research and Educational Trust.

  16. Nuclear electric capacity expansion in Mexico: system effects of reactor size and cost

    International Nuclear Information System (INIS)

    Thayer, G.R.; Abbey, D.S.; Hardie, R.W.; Enriquez, R.P.; Uria, E.G.

    1984-01-01

    Mexico's electrical generation capacity could more than double over the next ten years - from about 15 GWe currently to as much as 35 GWe in 1990. While new capacity additions will be predominantly oil-fired in the 1980's, nuclear power will become increasingly important in the 1990's. This study investigated the appropriate size of new, nuclear capacity additions by assessing the implications of installing different size reactors into Mexico's electrical grid. Included in the assessments of reactor sizes are estimates of electrical generation costs and comparisons of the effective load-carrying capability of a 10 GWe nuclear capacity expansion

  17. Catalytic activity of metallic nanoisland coatings. The influence of size effects on the recombination properties

    International Nuclear Information System (INIS)

    Tomilina, O A; Berzhansky, V N; Shaposhnikov, A N; Tomilin, S V

    2016-01-01

    The results of investigations of the quantum-size effects influence on selective properties of heterogeneous nanocatalysts are presents. As etalon exothermic reaction was used the reaction of atomic hydrogen recombination. The nanostructured Pd and Pt films on Teflon substrate were used as a samples of heterogeneous nanocatalysts. It was shown that for nanoparticles with various sizes the catalytic activity has the periodic dependence. It has been found that for certain sizes of nanoparticles their catalytic activity is less than that of Teflon substrate. (paper)

  18. Effect of grain size on tensile stress and ductility in Al99.99

    International Nuclear Information System (INIS)

    Kovacs-Csetenyi, E.; Horvath, M.; Chinh, N.Q.; Kovacs, I.

    1998-01-01

    The effect of recrystallized grain size on the tensile stress and ductility of 99.99% purity aluminium was investigated at room temperature. It was proved that the grain size dependence of flow stress follows a modified Hall-Petch equation with coefficients depending linearly on ε 1/2 up to the stability limit. The uniform strain can also be described by a linear dependence on d -1/2 according to which the uniform elongation increases with increasing grain size. The post-uniform elongation changes inversely to that of the uniform one accompanied by the decrease of the strain rate sensitivity. (orig.)

  19. Effect of colour and relative product size (RPS) on consumer attitudes

    OpenAIRE

    Varsha Jain; Subhadip Roy; Adwita Pant

    2013-01-01

    Colour and visuals are used extensively by the advertisers of different product categories to attract consumer attention and create favourable attitude. Based on this premise, the present study aimed to explore the effect of colour and relative product size on the consumer attitudes incorporating the moderating role of product familiarity. An experimental design was used, with a sample size of 420 respondents of 18-25 years in a 3 (Product Size: Large/Med/Small) X 2 (Ad Colour: CL/BW) X 2 (Ge...

  20. Size and surface effects on the magnetism of magnetite and maghemite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nikiforov, V. N., E-mail: pppnvn@yandex.ru [Moscow State University (Russian Federation); Ignatenko, A. N.; Irkhin, V. Yu. [Russian Academy of Sciences, Mikheev Institute of Metal Physics, Ural Branch (Russian Federation)

    2017-02-15

    The size effects of magnetite and maghemite nanoparticles on their magnetic properties (magnetic moment, Curie temperature, blocking temperature, etc.) have been investigated. Magnetic separation and centrifugation of an aqueous solution of nanoparticles were used for their separation into fractions; their sizes were measured by atomic force microscopy, dynamic light scattering, and electron microscopy. A change in the size leads to a change in the Curie temperature and magnetic moment per formula unit. Both native nanoparticles and those covered with a bioresorbable layer have been considered. The magnetic properties have been calculated by the Monte Carlo method for the classical Heisenberg model with various bulk and surface magnetic moments.