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Sample records for pre-post effect size

  1. Immediate stress reduction effects of yoga during pregnancy: One group pre-post test.

    Science.gov (United States)

    Kusaka, Momoko; Matsuzaki, Masayo; Shiraishi, Mie; Haruna, Megumi

    2016-10-01

    Excessive stress during pregnancy may cause mental disorders in pregnant women and inhibit fetal growth. Yoga may alleviate stress during pregnancy. To verify the immediate effects of yoga on stress response during pregnancy. One group pre-post test was conducted at a hospital in Japan. We recruited 60 healthy primiparas without complications and asked them to attend yoga classes twice a month and to practice yoga at their homes using DVD 3 times a week from 20 gestational weeks until childbirth. Salivary cortisol and alpha-amylase concentration were measured before and after yoga classes at time 1 (27-32 gestational weeks) and time 2 (34-37 gestational weeks). Subjective mood was assessed using the profile of mood states. Saliva values and mood scores before and after each yoga class were compared using paired t-test and Wilcoxon rank-sum test, respectively. We analyzed 44 and 35 women at time 1 and time 2, respectively. The mean salivary cortisol concentration declined significantly after each yoga class [time 1: 0.36-0.26μg/dL (pstress reduction effects of yoga during pregnancy. Copyright © 2016 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

  2. A patient's perspective on multidisciplinary treatment gain for fibromyalgia: an indicator for pre-post treatment effects?

    NARCIS (Netherlands)

    Koulil, S. van; Kraaimaat, F.W.; Lankveld, W.G.J.M. van; Riel, P.L.C.M. van; Evers, A.W.M.

    2009-01-01

    OBJECTIVE: Increasing attention is devoted to the patient's perspective in clinical research and practice. However, the relationship between the patient's view on treatment progress and standardized pre-post changes in health outcomes is not well understood. The objective of this study was to invest

  3. A patient's perspective on multidisciplinary treatment gain for fibromyalgia: an indicator for pre-post treatment effects?

    NARCIS (Netherlands)

    Koulil, S. van; Kraaimaat, F.W.; Lankveld, W.G.J.M. van; Riel, P.L.C.M. van; Evers, A.W.M.

    2009-01-01

    OBJECTIVE: Increasing attention is devoted to the patient's perspective in clinical research and practice. However, the relationship between the patient's view on treatment progress and standardized pre-post changes in health outcomes is not well understood. The objective of this study was to invest

  4. Effects of cervical mobilization and exercise on pain, movement and function in subjects with temporomandibular disorders: a single group pre-post test

    Science.gov (United States)

    CALIXTRE, Letícia Bojikian; GRÜNINGER, Bruno Leonardo da Silva; HAIK, Melina Nevoeiro; ALBURQUERQUE-SENDÍN, Francisco; OLIVEIRA, Ana Beatriz

    2016-01-01

    ABSTRACT Objective To investigate the effect of a rehabilitation program based on cervical mobilization and exercise on clinical signs and mandibular function in subjects with temporomandibular disorder (TMD). Material and Methods: Single-group pre-post test, with baseline comparison. Subjects Twelve women (22.08±2.23 years) with myofascial pain and mixed TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders. Outcome measures Subjects were evaluated three times: twice before (baseline phase) and once after intervention. Self-reported pain, jaw function [according to the Mandibular Functional Impairment Questionnaire (MFIQ)], pain-free maximum mouth opening (MMO), and pressure pain thresholds (PPTs) of both masseter and temporalis muscles were obtained. Baseline and post-intervention differences were investigated, and effect size was estimated through Cohen’s d coefficient. Results Jaw function improved 7 points on the scale after the intervention (P=0.019), and self-reported pain was significantly reduced (P=0.009). Pain-free MMO varied from 32.3±8.8 mm to 38±8.8 mm and showed significant improvement (P=0.017) with moderate effect size when compared to the baseline phase. PPT also increased with moderate effect size, and subjects had the baseline values changed from 1.23±0.2 kg/cm2 to 1.4±0.2 kg/cm2 in the left masseter (P=0.03), from 1.31±0.28 kg/cm2 to 1.51±0.2 kg/cm2 in the right masseter (P>0.05), from 1.32±0.2 kg/cm2 to 1.46±0.2 kg/cm2 in the left temporalis (P=0.047), and from 1.4±0.2 kg/cm2 to 1.67±0.3 kg/cm2 in the right temporalis (P=0.06). Conclusions The protocol caused significant changes in pain-free MMO, self-reported pain, and functionality of the stomatognathic system in subjects with myofascial TMD, regardless of joint involvement. Even though these differences are statistically significant, their clinical relevance is still questionable. PMID:27383698

  5. Effects of cervical mobilization and exercise on pain, movement and function in subjects with temporomandibular disorders: a single group pre-post test

    Directory of Open Access Journals (Sweden)

    Letícia Bojikian CALIXTRE

    Full Text Available ABSTRACT Objective To investigate the effect of a rehabilitation program based on cervical mobilization and exercise on clinical signs and mandibular function in subjects with temporomandibular disorder (TMD. Material and Methods: Single-group pre-post test, with baseline comparison. Subjects Twelve women (22.08±2.23 years with myofascial pain and mixed TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders. Outcome measures Subjects were evaluated three times: twice before (baseline phase and once after intervention. Self-reported pain, jaw function [according to the Mandibular Functional Impairment Questionnaire (MFIQ], pain-free maximum mouth opening (MMO, and pressure pain thresholds (PPTs of both masseter and temporalis muscles were obtained. Baseline and post-intervention differences were investigated, and effect size was estimated through Cohen’s d coefficient. Results Jaw function improved 7 points on the scale after the intervention (P=0.019, and self-reported pain was significantly reduced (P=0.009. Pain-free MMO varied from 32.3±8.8 mm to 38±8.8 mm and showed significant improvement (P=0.017 with moderate effect size when compared to the baseline phase. PPT also increased with moderate effect size, and subjects had the baseline values changed from 1.23±0.2 kg/cm2 to 1.4±0.2 kg/cm2 in the left masseter (P=0.03, from 1.31±0.28 kg/cm2 to 1.51±0.2 kg/cm2 in the right masseter (P>0.05, from 1.32±0.2 kg/cm2 to 1.46±0.2 kg/cm2 in the left temporalis (P=0.047, and from 1.4±0.2 kg/cm2 to 1.67±0.3 kg/cm2 in the right temporalis (P=0.06. Conclusions The protocol caused significant changes in pain-free MMO, self-reported pain, and functionality of the stomatognathic system in subjects with myofascial TMD, regardless of joint involvement. Even though these differences are statistically significant, their clinical relevance is still questionable.

  6. Effects of cervical mobilization and exercise on pain, movement and function in subjects with temporomandibular disorders: a single group pre-post test.

    Science.gov (United States)

    Calixtre, Letícia Bojikian; Grüninger, Bruno Leonardo da Silva; Haik, Melina Nevoeiro; Alburquerque-Sendín, Francisco; Oliveira, Ana Beatriz

    2016-01-01

    To investigate the effect of a rehabilitation program based on cervical mobilization and exercise on clinical signs and mandibular function in subjects with temporomandibular disorder (TMD). Single-group pre-post test, with baseline comparison. Twelve women (22.08±2.23 years) with myofascial pain and mixed TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders. Subjects were evaluated three times: twice before (baseline phase) and once after intervention. Self-reported pain, jaw function [according to the Mandibular Functional Impairment Questionnaire (MFIQ)], pain-free maximum mouth opening (MMO), and pressure pain thresholds (PPTs) of both masseter and temporalis muscles were obtained. Baseline and post-intervention differences were investigated, and effect size was estimated through Cohen's d coefficient. Jaw function improved 7 points on the scale after the intervention (P=0.019), and self-reported pain was significantly reduced (P=0.009). Pain-free MMO varied from 32.3±8.8 mm to 38±8.8 mm and showed significant improvement (P=0.017) with moderate effect size when compared to the baseline phase. PPT also increased with moderate effect size, and subjects had the baseline values changed from 1.23±0.2 kg/cm2 to 1.4±0.2 kg/cm2 in the left masseter (P=0.03), from 1.31±0.28 kg/cm2 to 1.51±0.2 kg/cm2 in the right masseter (P>0.05), from 1.32±0.2 kg/cm2 to 1.46±0.2 kg/cm2 in the left temporalis (P=0.047), and from 1.4±0.2 kg/cm2 to 1.67±0.3 kg/cm2 in the right temporalis (P=0.06). The protocol caused significant changes in pain-free MMO, self-reported pain, and functionality of the stomatognathic system in subjects with myofascial TMD, regardless of joint involvement. Even though these differences are statistically significant, their clinical relevance is still questionable.

  7. Effects of newly designed hospital buildings on staff perceptions : a pre-post study to validate design decisions

    NARCIS (Netherlands)

    Schreuder, E.J.A.; Heel, L. van; Goedhart, R.; Dusseldorp, E.; Schraagen, J.M.C.; Burdorf, A.

    2015-01-01

    Objective: This study investigates effects of the newly built nonpatient-related buildings of a large university medical center on staff perceptions and whether the design objectives were achieved. Background: The medical center is gradually renewing its hospital building area of 200,000 m.(2) This

  8. Effectiveness of interprofessional education by on-field training for medical students, with a pre-post design.

    Science.gov (United States)

    Zanotti, Renzo; Sartor, Giada; Canova, Cristina

    2015-07-29

    Interprofessional Education (IPE) implies how to achieve successful teamwork, and is based on collaborative practice which enhance occasions for relationships between two or more healthcare professions. This study evaluates the effectiveness of IPE in changing attitudes after a training recently introduced to medical education for second-year students at the University of Padova, Italy. All medical students following a new program for IPE were enrolled in this study. The Interdisciplinary Education Perception Scale (IEPS) was administered before and after training, according to observation-based and practice-based learning. Data were analysed with Student's paired t-test and Wilcoxon's signed rank test. 277 medical students completed both questionnaires. Statistically significant improvements were found in students' overall attitudes as measured by the IEPS and four subscale scores. Gender-stratified analyses showed that improvements were observed only in female students in subscale 4 ("Understanding Others' Values"). Students who had a physician and/or health worker in their family did not show any improvement in subscales 2 ("Perceived need for cooperation") or 4 ("Understanding Others' Values"). Our results indicate that IPE training has a positive influence on students' understanding of collaboration and better attitudes in interprofessional teamwork. More research is needed to explore other factors which may influence specific perceptions among medical students.

  9. Pre-Post Tornado Effects on Aggressive Children's Psychological and Behavioral Adjustment Through One-Year Postdisaster.

    Science.gov (United States)

    Lochman, John E; Vernberg, Eric; Powell, Nicole P; Boxmeyer, Caroline L; Jarrett, Matthew; McDonald, Kristina; Qu, Lixin; Hendrickson, Michelle; Kassing, Francesca

    2017-01-01

    Using a risk-resilience framework, this study examined how varying levels of exposure to a natural disaster (EF-4 tornado) and children's characteristics (sex; anxiety) influenced the behavioral and psychological adjustment of children who shared a common risk factor predisaster (elevated aggression) prior to exposure through 1-year postdisaster. Participants included 360 children in Grades 4-6 (65% male; 78% African American) and their parents from predominantly low-income households who were already participating in a longitudinal study of indicated prevention effects for externalizing outcomes when the tornado occurred in 2011. Fourth-grade children who were screened for overt aggressive behavior were recruited in 3 annual cohorts (120 per year, beginning in 2009). Parent-rated aggression and internalizing problems were assessed prior to the tornado (Wave 1), within a half-year after the tornado (Wave 2), and at a 1-year follow-up (Wave 3). Children and parents rated their exposure to aspects of tornado-related traumatic experiences at Wave 3. Children displayed less reduction on aggression and internalizing problems if the children had experienced distress after the tornado or fears for their life, in combination with their pre-tornado level of anxiety. Higher levels of children's and parents' exposure to the tornado interacted with children's lower baseline child anxiety to predict less reduction in aggression and internalizing problems 1 year after the tornado. Higher levels of disaster exposure negatively affected at-risk children's level of improvement in aggression and internalizing problems, when life threat (parent- and child-reported) and child-reported distress after the tornado were moderated by baseline anxiety.

  10. Effects of Newly Designed Hospital Buildings on Staff Perceptions: A Pre-Post Study to Validate Design Decisions.

    Science.gov (United States)

    Schreuder, Eliane; van Heel, Liesbeth; Goedhart, Rien; Dusseldorp, Elise; Schraagen, Jan Maarten; Burdorf, Alex

    2015-01-01

    This study investigates effects of the newly built nonpatient-related buildings of a large university medical center on staff perceptions and whether the design objectives were achieved. The medical center is gradually renewing its hospital building area of 200,000 m.(2) This redevelopment is carefully planned and because lessons learned can guide design decisions of the next phase, the medical center is keen to evaluate the performance of the new buildings. A pre- and post-study with a control group was conducted. Prior to the move to the new buildings an occupancy evaluation was carried out in the old setting (n = 729) (pre-study). Post occupation of the new buildings another occupancy evaluation (post-study) was carried out in the new setting (intervention group) and again in some old settings (control group) (n = 664). The occupancy evaluation consisted of an online survey that measured the perceived performance of different aspects of the building. Longitudinal multilevel analysis was used to compare the performance of the old buildings with the new buildings. Significant improvements were found in indoor climate, perceived safety, working environment, well-being, facilities, sustainability, and overall satisfaction. Commitment to the employer, working atmosphere, orientation, work performance, and knowledge sharing did not improve. The results were interpreted by relating them to specific design choices. We showed that it is possible to measure the performance improvements of a complex intervention being a new building design and validate design decisions. A focused design process aiming for a safe, pleasant and sustainable building resulted in actual improvements in some of the related performance measures. © The Author(s) 2015.

  11. Effect of beta-alanine supplementation on the onset of blood lactate accumulation (OBLA during treadmill running: Pre/post 2 treatment experimental design

    Directory of Open Access Journals (Sweden)

    Misic Mark

    2010-05-01

    Full Text Available Abstract Background β-Alanine (βA has been shown to improve performance during cycling. This study was the first to examine the effects of βA supplementation on the onset of blood lactate accumulation (OBLA during incremental treadmill running. Methods Seventeen recreationally-active men (mean ± SE 24.9 ± 4.7 yrs, 180.6 ± 8.9 cm, 79.25 ± 9.0 kg participated in this randomized, double-blind, placebo-controlled pre/post test 2-treatment experimental design. Subjects participated in two incremental treadmill tests before and after 28 days of supplementation with either βA (6.0 g·d-1(βA, n = 8 or an equivalent dose of Maltodextrin as the Placebo (PL, n = 9. Heart rate, percent heart rate maximum (%HRmax, %VO2max@OBLA (4.0 mmol.L-1 blood lactate concentration and VO2max (L.min-1 were determined for each treadmill test. Friedman test was used to determine within group differences; and Mann-Whitney was used to determine between group differences for pre and post values (p Results The βA group experienced a significant rightward shift in HR@OBLA beats.min-1 (p 2max@OBLA increased (p 2max (L.min-1 decreased (p Conclusions βA supplementation for 28 days enhanced sub-maximal endurance performance by delaying OBLA. However, βA supplemented individuals had a reduced aerobic capacity as evidenced by the decrease in VO2max values post supplementation.

  12. Assumption Trade-Offs When Choosing Identification Strategies for Pre-Post Treatment Effect Estimation: An Illustration of a Community-Based Intervention in Madagascar.

    Science.gov (United States)

    Weber, Ann M; van der Laan, Mark J; Petersen, Maya L

    2015-03-01

    Failure (or success) in finding a statistically significant effect of a large-scale intervention may be due to choices made in the evaluation. To highlight the potential limitations and pitfalls of some common identification strategies used for estimating causal effects of community-level interventions, we apply a roadmap for causal inference to a pre-post evaluation of a national nutrition program in Madagascar. Selection into the program was non-random and strongly associated with the pre-treatment (lagged) outcome. Using structural causal models (SCM), directed acyclic graphs (DAGs) and simulated data, we illustrate that an estimand with the outcome defined as the post-treatment outcome controls for confounding by the lagged outcome but not by possible unmeasured confounders. Two separate differencing estimands (of the pre- and post-treatment outcome) have the potential to adjust for a certain type of unmeasured confounding, but introduce bias if the additional identification assumptions they rely on are not met. In order to illustrate the practical impact of choice between three common identification strategies and their corresponding estimands, we used observational data from the community nutrition program in Madagascar to estimate each of these three estimands. Specifically, we estimated the average treatment effect of the program on the community mean nutritional status of children 5 years and under and found that the estimate based on the post-treatment estimand was about a quarter of the magnitude of either of the differencing estimands (0.066 SD vs. 0.26-0.27 SD increase in mean weight-for-age z-score). Choice of estimand clearly has important implications for the interpretation of the success of the program to improve nutritional status of young children. A careful appraisal of the assumptions underlying the causal model is imperative before committing to a statistical model and progressing to estimation. However, knowledge about the data

  13. Effects of jump and balance training on knee kinematics and electromyography of female basketball athletes during a single limb drop landing: pre-post intervention study

    OpenAIRE

    2011-01-01

    Abstract Background Some research studies have investigated the effects of anterior cruciate ligament (ACL) injury prevention programs on knee kinematics during landing tasks; however the results were different among the studies. Even though tibial rotation is usually observed at the time of ACL injury, the effects of training programs for knee kinematics in the horizontal plane have not yet been analyzed. The purpose of this study was to determine the effects of a jump and balance training p...

  14. Effects of jump and balance training on knee kinematics and electromyography of female basketball athletes during a single limb drop landing: pre-post intervention study

    Directory of Open Access Journals (Sweden)

    Nagano Yasuharu

    2011-07-01

    Full Text Available Abstract Background Some research studies have investigated the effects of anterior cruciate ligament (ACL injury prevention programs on knee kinematics during landing tasks; however the results were different among the studies. Even though tibial rotation is usually observed at the time of ACL injury, the effects of training programs for knee kinematics in the horizontal plane have not yet been analyzed. The purpose of this study was to determine the effects of a jump and balance training program on knee kinematics including tibial rotation as well as on electromyography of the quadriceps and hamstrings in female athletes. Methods Eight female basketball athletes participated in the experiment. All subjects performed a single limb landing at three different times: the initial test, five weeks later, and one week after completing training. The jump and balance training program lasted for five weeks. Knee kinematics and simultaneous electromyography of the rectus femoris and Hamstrings before training were compared with those measured after completing the training program. Results After training, regarding the position of the knee at foot contact, the knee flexion angle for the Post-training trial (mean (SE: 24.4 (2.1 deg was significantly larger than that for the Pre-training trial (19.3 (2.5 deg (p Conclusions The jump and balance training program successfully increased knee flexion and hamstring activity of female athletes during landing, and has the possibility of producing partial effects to avoid the characteristic knee position observed in ACL injury, thereby preventing injury. However, the expected changes in frontal and transverse kinematics of the knee were not observed.

  15. Effect of the new maternity insurance scheme on medical expenditures for caesarean delivery in Wuxi, China: a retrospective pre/post-reform case study.

    Science.gov (United States)

    Chen, Chun; Cheng, Zhihong; Jiang, Ping; Sun, Mei; Zhang, Qi; Lv, Jun

    2016-12-01

    Aiming to control rising medical expenditures and help improve China's healthcare systems, this study examined whether a cap-based medical insurance scheme with shared financial interest between the insurance and healthcare providers is effective in containing hospitals' C-section medical expenditures. We used 6547 caesarean delivery case records from a teaching tertiary-level general public hospital located in Wuxi, China (2004-2013), and used the Chow test to investigate the possibility of significant variation in mean medical expenditures for caesarean deliveries pre- and post-reform. We also used paired sample t-tests and linear regression models to compare the mean medical expenditures between insured and uninsured women undergoing caesarean delivery during the post-reform period. After the scheme's implementation, medical expenditures for caesarean deliveries declined and the medical expenditures of women covered by the scheme were significantly lower than those of uninsured patients. These findings indicated the scheme's effectiveness in minimizing caesarean delivery expenditures. The cap-based medical insurance scheme with shared financial interest between insurance and healthcare providers would likely steer healthcare providers' behaviors in a more cost-effective direction.

  16. Effectiveness of resistance training in combination with botulinum toxin-A on hand and arm use in children with cerebral palsy: a pre-post intervention study.

    Science.gov (United States)

    Elvrum, Ann-Kristin G; Brændvik, Siri M; Sæther, Rannei; Lamvik, Torarin; Vereijken, Beatrix; Roeleveld, Karin

    2012-07-02

    The aim of this pilot study was to examine the effects of additional resistance training after use of Botulinum Toxin-A (BoNT-A) on the upper limbs in children with cerebral palsy (CP). Ten children with CP (9-17 years) with unilaterally affected upper limbs according to Manual Ability Classification System II were assigned to two intervention groups. One group received BoNT-A treatment (group B), the other BoNT-A plus eight weeks resistance training (group BT). Hand and arm use were evaluated by means of the Melbourne assessment of unilateral upper limb function (Melbourne) and Assisting Hand Assessment (AHA). Measures of muscle strength, muscle tone, and active range of motion were used to assess neuromuscular body function. Measurements were performed before and two and five months after intervention start. Change scores and differences between the groups in such scores were subjected to Mann-Whitney U and Wilcoxon Signed Rank tests, respectively. Both groups had very small improvements in AHA and Melbourne two months after BoNT-A injections, without differences between groups. There were significant, or close to significant, short-term treatment effects in favour of group BT for muscle strength in injected muscles (elbow flexion strength, p = .08) and non-injected muscles (elbow extension and supination strength, both p = .05), without concomitant increases in muscle tone. Active supination range improved in both groups, but more so in group BT (p = .09). There were no differences between the groups five months after intervention start. Resistance training strengthens non-injected muscles temporarily and may reduce short-term strength loss that results from BoNT-A injections without increasing muscle tone. Moreover, additional resistance training may increase active range of motion to a greater extent than BoNT-A alone. None of the improvements in neuromuscular impairments further augmented use of the hand and arm. Larger clinical trials are needed to

  17. Effectiveness of resistance training in combination with botulinum toxin-A on hand and arm use in children with cerebral palsy: a pre-post intervention study

    Directory of Open Access Journals (Sweden)

    Elvrum Ann-Kristin G

    2012-07-01

    Full Text Available Abstract Background The aim of this pilot study was to examine the effects of additional resistance training after use of Botulinum Toxin-A (BoNT-A on the upper limbs in children with cerebral palsy (CP. Methods Ten children with CP (9–17 years with unilaterally affected upper limbs according to Manual Ability Classification System II were assigned to two intervention groups. One group received BoNT-A treatment (group B, the other BoNT-A plus eight weeks resistance training (group BT. Hand and arm use were evaluated by means of the Melbourne assessment of unilateral upper limb function (Melbourne and Assisting Hand Assessment (AHA. Measures of muscle strength, muscle tone, and active range of motion were used to assess neuromuscular body function. Measurements were performed before and two and five months after intervention start. Change scores and differences between the groups in such scores were subjected to Mann–Whitney U and Wilcoxon Signed Rank tests, respectively. Results Both groups had very small improvements in AHA and Melbourne two months after BoNT-A injections, without differences between groups. There were significant, or close to significant, short-term treatment effects in favour of group BT for muscle strength in injected muscles (elbow flexion strength, p = .08 and non-injected muscles (elbow extension and supination strength, both p = .05, without concomitant increases in muscle tone. Active supination range improved in both groups, but more so in group BT (p = .09. There were no differences between the groups five months after intervention start. Conclusions Resistance training strengthens non-injected muscles temporarily and may reduce short-term strength loss that results from BoNT-A injections without increasing muscle tone. Moreover, additional resistance training may increase active range of motion to a greater extent than BoNT-A alone. None of the improvements in neuromuscular impairments further

  18. Pre/post-strike atmospheric assessment system (PAAS)

    Energy Technology Data Exchange (ETDEWEB)

    Peglow, S. G., LLNL; Molitoris, J. D., LLNL

    1997-02-03

    The Pre/Post-Strike Atmospheric Assessment System was proposed to show the importance of local meteorological conditions in the vicinity of a site suspected of storing or producing toxic agents and demonstrate a technology to measure these conditions, specifically wind fields. The ability to predict the collateral effects resulting from an attack on a facility containing hazardous materials is crucial to conducting effective military operations. Our study approach utilized a combination of field measurements with dispersion modeling to better understand which variables in terrain and weather were most important to collateral damage predictions. To develop the PAAS wind-sensing technology, we utilized a combination of emergent and available technology from micro-Doppler and highly coherent laser systems. The method used for wind sensing is to probe the atmosphere with a highly coherent laser beam. As the beam probes, light is back-scattered from particles entrained in the air to the lidar transceiver and detected by the instrument. Any motion of the aerosols with a component along the beam axis leads to a Doppler shift of the received light. Scanning in a conical fashion about the zenith results in a more accurate and two-dimensional measurement of the wind velocity. The major milestones in the benchtop system development were to verify the design by demonstrating the technique in the laboratory, then scale the design down to a size consistent with a demonstrator unit which could be built to take data in the field. The micro-Doppler heterodyne system we developed determines absolute motion by optically mixing a reference beam with the return signal and has shown motion sensitivity to better than 1 cm/s. This report describes the rationale, technical approach and laboratory testing undertaken to demonstrate the feasibility and utility of a system to provide local meteorological data and predict atmospheric particulate motion. The work described herein was funded by

  19. Does the Incredible Years Teacher Classroom Management Training programme have positive effects for young children exhibiting severe externalizing problems in school?: a quasi-experimental pre-post study

    Directory of Open Access Journals (Sweden)

    Bente Kirkhaug

    2016-10-01

    Full Text Available Abstract Background Young children exhibiting severe externalizing problems in school are at risk of developing several poor outcomes. School-based intervention programs have been found to be effective for students with different problems, including those with behavioral problems, emotional distress, or social problems. The present study investigated whether the IY-TCM programme, as a universal stand-alone school intervention programme, reduced severe child externalizing problems as reported by the teacher, and evaluated if these children improved their social competence, internalizing problems, academic performances and student- teacher relationship as a result of the IY TCM training. Methods A quasi-experimental pre-post study was conducted, including 21 intervention schools and 22 control schools. Children in 1st – 3rd grade (age 6–8 years assessed by their teacher as having severe externalizing problems on the Sutter–Eyberg Student Behavior Inventory-Revised (SESBI-R total Intensity score, were included in the study, N = 83 (65 boys and 18 girls. Treatment effects were evaluated using 3- level linear mixed models analysis. Results In our study we found no differences in change between the two conditions from baseline to follow-up in externalizing problems, social skills, internalizing problems and closeness with teacher. The intervention condition did however show advantageous development in terms of student-teacher conflicts and increased academic performances. Conclusion The IY Teacher Classroom Management program is not sufficient being a stand-alone universal program in a Norwegian primary school setting, for students with severe externalizing problems. However; some important secondary findings were found. Still, young school children with severe externalizing problems are in need of more comprehensive and tailored interventions.

  20. Does the Incredible Years Teacher Classroom Management Training programme have positive effects for young children exhibiting severe externalizing problems in school?: a quasi-experimental pre-post study.

    Science.gov (United States)

    Kirkhaug, Bente; Drugli, May Britt; Handegård, Bjørn Helge; Lydersen, Stian; Åsheim, Merethe; Fossum, Sturla

    2016-10-26

    Young children exhibiting severe externalizing problems in school are at risk of developing several poor outcomes. School-based intervention programs have been found to be effective for students with different problems, including those with behavioral problems, emotional distress, or social problems. The present study investigated whether the IY-TCM programme, as a universal stand-alone school intervention programme, reduced severe child externalizing problems as reported by the teacher, and evaluated if these children improved their social competence, internalizing problems, academic performances and student- teacher relationship as a result of the IY TCM training. A quasi-experimental pre-post study was conducted, including 21 intervention schools and 22 control schools. Children in 1(st) - 3(rd) grade (age 6-8 years) assessed by their teacher as having severe externalizing problems on the Sutter-Eyberg Student Behavior Inventory-Revised (SESBI-R) total Intensity score, were included in the study, N = 83 (65 boys and 18 girls). Treatment effects were evaluated using 3- level linear mixed models analysis. In our study we found no differences in change between the two conditions from baseline to follow-up in externalizing problems, social skills, internalizing problems and closeness with teacher. The intervention condition did however show advantageous development in terms of student-teacher conflicts and increased academic performances. The IY Teacher Classroom Management program is not sufficient being a stand-alone universal program in a Norwegian primary school setting, for students with severe externalizing problems. However; some important secondary findings were found. Still, young school children with severe externalizing problems are in need of more comprehensive and tailored interventions.

  1. On Effect Size

    Science.gov (United States)

    Kelley, Ken; Preacher, Kristopher J.

    2012-01-01

    The call for researchers to report and interpret effect sizes and their corresponding confidence intervals has never been stronger. However, there is confusion in the literature on the definition of effect size, and consequently the term is used inconsistently. We propose a definition for effect size, discuss 3 facets of effect size (dimension,…

  2. On Effect Size

    Science.gov (United States)

    Kelley, Ken; Preacher, Kristopher J.

    2012-01-01

    The call for researchers to report and interpret effect sizes and their corresponding confidence intervals has never been stronger. However, there is confusion in the literature on the definition of effect size, and consequently the term is used inconsistently. We propose a definition for effect size, discuss 3 facets of effect size (dimension,…

  3. Creating Leaders: A Pilot Pre/Post Evaluation of an Ontological/Phenomenological Model

    Science.gov (United States)

    Carney, Nancy; Jensen, Michael; Ballarini, Nicolas; Echeverria, Jeronima; Nettleton, Tracie; Stillwell, Molly; Erhard, Werner

    2016-01-01

    This pilot is a pre/post comparative assessment of a leadership course developed and delivered using an innovative, ontological/phenomenological model of education. Participants in the course delivered in Singapore in July of 2014 provided measures of the effectiveness of their leadership before and after the course, using a scale from 1 (least…

  4. Correlational effect size benchmarks.

    Science.gov (United States)

    Bosco, Frank A; Aguinis, Herman; Singh, Kulraj; Field, James G; Pierce, Charles A

    2015-03-01

    Effect size information is essential for the scientific enterprise and plays an increasingly central role in the scientific process. We extracted 147,328 correlations and developed a hierarchical taxonomy of variables reported in Journal of Applied Psychology and Personnel Psychology from 1980 to 2010 to produce empirical effect size benchmarks at the omnibus level, for 20 common research domains, and for an even finer grained level of generality. Results indicate that the usual interpretation and classification of effect sizes as small, medium, and large bear almost no resemblance to findings in the field, because distributions of effect sizes exhibit tertile partitions at values approximately one-half to one-third those intuited by Cohen (1988). Our results offer information that can be used for research planning and design purposes, such as producing better informed non-nil hypotheses and estimating statistical power and planning sample size accordingly. We also offer information useful for understanding the relative importance of the effect sizes found in a particular study in relationship to others and which research domains have advanced more or less, given that larger effect sizes indicate a better understanding of a phenomenon. Also, our study offers information about research domains for which the investigation of moderating effects may be more fruitful and provide information that is likely to facilitate the implementation of Bayesian analysis. Finally, our study offers information that practitioners can use to evaluate the relative effectiveness of various types of interventions. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  5. Quenched effective population size

    CERN Document Server

    Sagitov, Serik; Vatutin, Vladimir

    2010-01-01

    We study the genealogy of a geographically - or otherwise - structured version of the Wright-Fisher population model with fast migration. The new feature is that migration probabilities may change in a random fashion. Applying Takahashi's results on Markov chains with random transition matrices, we establish convergence to the Kingman coalescent, as the population size goes to infinity. This brings a novel formula for the coalescent effective population size (EPS). We call it a quenched EPS to emphasize the key feature of our model - random environment. The quenched EPS is compared with an annealed (mean-field) EPS which describes the case of constant migration probabilities obtained by averaging the random migration probabilities over possible environments.

  6. Intradialytic Laughter Yoga therapy for haemodialysis patients: a pre-post intervention feasibility study.

    Science.gov (United States)

    Bennett, Paul N; Parsons, Trisha; Ben-Moshe, Ros; Neal, Merv; Weinberg, Melissa K; Gilbert, Karen; Ockerby, Cherene; Rawson, Helen; Herbu, Corinne; Hutchinson, Alison M

    2015-06-09

    Laughter Yoga consists of physical exercise, relaxation techniques and simulated vigorous laughter. It has been associated with physical and psychological benefits for people in diverse clinical and non-clinical settings, but has not yet been tested in a haemodialysis setting. The study had three aims: 1) to examine the feasibility of conducting Laughter Yoga for patients with end stage kidney disease in a dialysis setting; 2) to explore the psychological and physiological impact of Laughter Yoga for these patients; and 3) to estimate the sample size required for future research. Pre/post intervention feasibility study. Eighteen participants were recruited into the study and Laughter Yoga therapists provided a four week intradialytic program (30-min intervention three times per week). Primary outcomes were psychological items measured at the first and last Laughter Yoga session, including: quality of life; subjective wellbeing; mood; optimism; control; self-esteem; depression, anxiety and stress. Secondary outcomes were: blood pressure, intradialytic hypotensive episodes and lung function (forced expiratory volume). Dialysis nurses exposed to the intervention completed a Laughter Yoga attitudes and perceptions survey (n = 11). Data were analysed using IBM SPSS Statistics v22, including descriptive and inferential statistics, and sample size estimates were calculated using G*Power. One participant withdrew from the study for medical reasons that were unrelated to the study during the first week (94 % retention rate). There were non-significant increases in happiness, mood, and optimism and a decrease in stress. Episodes of intradialytic hypotension decreased from 19 pre and 19 during Laughter Yoga to 4 post Laughter Yoga. There was no change in lung function or blood pressure. All nurses agreed or strongly agreed that Laughter Yoga had a positive impact on patients' mood, it was a feasible intervention and they would recommend Laughter Yoga to their patients. Sample

  7. A Mobile Phone-Based Life Skills Training Program for Substance Use Prevention Among Adolescents: Pre-Post Study on the Acceptance and Potential Effectiveness of the Program, Ready4life.

    Science.gov (United States)

    Haug, Severin; Paz Castro, Raquel; Meyer, Christian; Filler, Andreas; Kowatsch, Tobias; Schaub, Michael P

    2017-10-04

    Substance use and misuse often first emerge during adolescence. Generic life skills training that is typically conducted within the school curriculum is effective at preventing the onset and escalation of substance use among adolescents. However, the dissemination of such programs is impeded by their large resource requirements in terms of personnel, money, and time. Life skills training provided via mobile phones might be a more economic and scalable approach, which additionally matches the lifestyle and communication habits of adolescents. The aim of this study was to test the acceptance and initial effectiveness of an individually tailored mobile phone-based life skills training program in vocational school students. The fully automated program, named ready4life, is based on social cognitive theory and addresses self-management skills, social skills, and substance use resistance skills. Program participants received up to 3 weekly text messages (short message service, SMS) over 6 months. Active program engagement was stimulated by interactive features such as quiz questions, message- and picture-contests, and integration of a friendly competition with prizes in which program users collected credits with each interaction. Generalized estimating equation (GEE) analyses were used to investigate for changes between baseline and 6-month follow-up in the following outcomes: perceived stress, self-management skills, social skills, at-risk alcohol use, tobacco smoking, and cannabis use. The program was tested in 118 school classes at 13 vocational schools in Switzerland. A total of 1067 students who owned a mobile phone and were not regular cigarette smokers were invited to participate in the life skills program. Of these, 877 (82.19%, 877/1067; mean age=17.4 years, standard deviation [SD]=2.7; 58.3% females) participated in the program and the associated study. A total of 43 students (4.9%, 43/877) withdrew their program participation during the intervention period

  8. Effect sizes in memory research.

    Science.gov (United States)

    Morris, Peter E; Fritz, Catherine O

    2013-01-01

    Effect sizes are omitted from many research articles and are rarely discussed. To help researchers evaluate effect sizes we collected values for the more commonly reported effect size measures (partial eta squared and d) from papers reporting memory research published in 2010. Cohen's small, medium, and large generic guideline values for d mapped neatly onto the observed distributions, but his values for partial eta squared were considerably lower than those observed in current memory research. We recommend interpreting effect sizes in the context of either domain-specific guideline values agreed for an area of research or the distribution of effect size estimates from published research in the domain. We provide cumulative frequency tables for both partial eta squared and d enabling authors to report and consider not only the absolute size of observed effects but also the percentage of reported effects that are larger or smaller than those observed.

  9. Size Effect in Continuum Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei-Yang [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials; Foulk, James W. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials; Huestis, Edwin M. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials; Connelly, Kevin [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials; Song, Bo [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials; Yang, Nancy Y. C. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Engineered Materials

    2008-09-01

    The mechanical properties of some materials (Cu, Ni, Ag, etc.) have been shown to develop strong dependence on the geometric dimensions, resulting in a size effect. Several theories have been proposed to model size effects, but have been based on very few experiments conducted at appropriate scales. Some experimental results implied that size effects are caused by increasing strain gradients and have been used to confirm many strain gradient theories. On the other hand, some recent experiments show that a size effect exists in the absence of strain gradients. This report describes a brief analytical and experimental study trying to clarify the material and experimental issues surrounding the most influential size-effect experiments by Fleck et al (1994). This effort is to understand size effects intended to further develop predictive models.

  10. Breton Island Transects with Shoreline Change Rates (Pre/Post Hurricane Katrina) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (Pre/Post Hurricane Katrina) (Geographic, NAD83) consists of vector transect data that were derived...

  11. Breton Island Transects with Shoreline Change Rates (Pre/Post Hurricane Katrina) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (Pre/Post Hurricane Katrina) (Geographic, NAD83) consists of vector transect data that were derived...

  12. Size effect in thermoelectric materials

    Science.gov (United States)

    Mao, Jun; Liu, Zihang; Ren, Zhifeng

    2016-12-01

    Thermoelectric applications have attracted increasing interest recently due to its capability of converting waste heat into electricity without hazardous emissions. Materials with enhanced thermoelectric performance have been reported in recent two decades. The revival of research for thermoelectric materials began in early 1990s when the size effect is considered. Low-dimensional materials with exceptionally high thermoelectric figure of merit (ZT) have been presented, which broke the limit of ZT around unity. The idea of size effect in thermoelectric materials even inspired the later nanostructuring and band engineering strategies, which effectively enhanced the thermoelectric performance of bulk materials. In this overview, the size effect in low-dimensional thermoelectric materials is reviewed. We first discuss the quantum confinement effect on carriers, including the enhancement of electronic density of states, semimetal to semiconductor transition and carrier pocket engineering. Then, the effect of assumptions on theoretical calculations is presented. Finally, the effect of phonon confinement and interface scattering on lattice thermal conductivity is discussed.

  13. Effect Size in Clinical Phonology

    Science.gov (United States)

    Gierut, Judith A.; Morrisette, Michele L.

    2011-01-01

    The purpose of this article is to motivate the use of effect size (ES) for single-subject research in clinical phonology, with an eye towards meta-analyses of treatment effects for children with phonological disorders. Standard mean difference (SMD) is introduced and illustrated as one ES well suited to the multiple baseline (MBL) design and…

  14. Effect Size in Clinical Phonology

    Science.gov (United States)

    Gierut, Judith A.; Morrisette, Michele L.

    2011-01-01

    The purpose of this article is to motivate the use of effect size (ES) for single-subject research in clinical phonology, with an eye towards meta-analyses of treatment effects for children with phonological disorders. Standard mean difference (SMD) is introduced and illustrated as one ES well suited to the multiple baseline (MBL) design and…

  15. 体验式培训在社区舒缓疗护护士上岗前的实践与效果%Practice and effect of the experiential-based pre-post training about palliative treatment and care for the community nurses

    Institute of Scientific and Technical Information of China (English)

    刘颖颜; 明星; 杨敏; 朱波琴; 蒋申贞; 李宁; 江长缨; 梅久红

    2016-01-01

    目的:探讨社区舒缓疗护护士上岗前实施体验式培训的效果。方法:采用目的抽样方法选择40名社区舒缓疗护护士,运用情景模拟、案例分享、总结体会、实践应用等理论与临床实践相结合的体验式培训,并使用自行设计的社区护士舒缓疗护知识调查问卷、人际反应指针问卷(IRI-C)分别于培训前、后对护士进行测评。结果:护士的舒缓疗护知识总分高于培训前,差异有统计学意义(P<0.01),其中舒缓疗护概述、心理护理、灵性关怀知识得分高于培训前;人际反应总分培训前、后差异有统计学意义(P<0.05)。其中,幻想力、身心忧急得分均高于培训前(P<0.05)。结论:体验式培训是提高社区护士舒缓疗护知识与技能、共情能力的有效培训方法。%Objective:To explore the effect of the experiential-based pre-post training about palliative treatment and care for thecommunity nurses.Methods: With the purposive sampling method, 40 community palliative nurses were chosen and given the experience-based training combined with theory and clinical practice such as the application of scenario simulation, case sharing, summing up experience and practical application. The self designed questionnaire of community nurses’ knowledge about palliative care and the interpersonal reactivity index questionnaire were used to evaluate the effects of the training for nurses before and after the training, respectively.Results: The total score of hospice care knowledge of the nurses was higher after training than that before training(P<0.01), among which the scores of an overview of the palliative care knowledge, psychological care and spiritual care knowledge were higher after training than those before training. The difference in the interpersonal reactivity index had the statistical signiifcance before and after training(P<0.05), among which the scores of fancy and physical and

  16. Effect size in clinical phonology

    OpenAIRE

    GIERUT, JUDITH A.; Morrisette, Michele L.

    2011-01-01

    The purpose of this article is to motivate the use of effect size (ES) for single-subject research in clinical phonology, with an eye towards meta-analyses of treatment effects for children with phonological disorders. Standard mean difference (SMD) is introduced and illustrated as one ES well suited to the multiple baseline (MBL) design and evaluation of generalization learning, both of which are key to experimental studies in clinical phonology.

  17. 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...

  18. 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.…

  19. 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.…

  20. School size effects: review and conceptual analysis

    NARCIS (Netherlands)

    Scheerens, Jaap; Hendriks, Maria; Luyten, Hans; Luyten, Hans; Hendriks, Maria; Scheerens, Jaap

    2014-01-01

    In this chapter, a review of international review studies on school size effects is presented. Next, ingredients of a more contextualized and tentative causal mediation model of school size effects are discussed. The chapter is completed by a short overview of school size effects as found in interna

  1. 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. 

  2. 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...

  3. Size effects on cavitation instabilities

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2006-01-01

    In metal-ceramic systems the constraint on plastic flow leads to so high stress triaxialities that cavitation instabilities may occur. If the void radius is on the order of magnitude of a characteristic length for the metal, the rate of void growth is reduced, and the possibility of unstable cavi...... as the void grows to a size well above the characteristic material length....

  4. Reducing child abuse amongst adolescents in low- and middle-income countries: A pre-post trial in South Africa.

    Science.gov (United States)

    Cluver, Lucie; Meinck, Franziska; Yakubovich, Alexa; Doubt, Jenny; Redfern, Alice; Ward, Catherine; Salah, Nasteha; De Stone, Sachin; Petersen, Tshiamo; Mpimpilashe, Phelisa; Romero, Rocio Herrero; Ncobo, Lulu; Lachman, Jamie; Tsoanyane, Sibongile; Shenderovich, Yulia; Loening, Heidi; Byrne, Jasmina; Sherr, Lorraine; Kaplan, Lauren; Gardner, Frances

    2016-07-13

    No known studies have tested the effectiveness of child abuse prevention programmes for adolescents in low- or middle-income countries. 'Parenting for Lifelong Health' ( http://tiny.cc/whoPLH ) is a collaborative project to develop and rigorously test abuse-prevention parenting programmes for free use in low-resource contexts. Research aims of this first pre-post trial in South Africa were: i) to identify indicative effects of the programme on child abuse and related outcomes; ii) to investigate programme safety for testing in a future randomised trial, and iii) to identify potential adaptations. Two hundred thirty participants (adolescents and their primary caregivers) were recruited from schools, welfare services and community-sampling in rural, high-poverty South Africa (no exclusion criteria). All participated in a 12-week parenting programme, implemented by local NGO childcare workers to ensure real-world external validity. Standardised pre-post measures with adolescents and caregivers were used, and paired t-tests were conducted for primary outcomes: abuse (physical, emotional abuse and neglect), adolescent behaviour problems and parenting (positive and involved parenting, poor monitoring and inconsistent discipline), and secondary outcomes: mental health, social support and substance use. Participants reported high levels of socio-economic deprivation, e.g. 60 % of adolescents had either an HIV-positive caregiver or were orphaned by AIDS, and 50 % of caregivers experienced intimate partner violence. i) indicative effects: Primary outcomes comparing pre-test and post-test assessments showed reductions reported by adolescents and caregivers in child abuse (adolescent report 63.0 % pre-test to 29.5 % post-test, caregiver report 75.5 % pre-test to 36.5 % post-test, both p child abuse and improved caregiver and adolescent outcomes. It showed high acceptability and unexpected community-level diffusion. Findings indicate needs for adaptations, and

  5. Do class size effects differ across grades?

    DEFF Research Database (Denmark)

    Nandrup, Anne Brink

    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...... 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...

  6. 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

  7. 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.

  8. Size and value effects in Suriname

    NARCIS (Netherlands)

    D.S. Bodeutsch (Denice); Ph.H.B.F. Franses (Philip Hans)

    2013-01-01

    markdownabstract__Abstract__ This paper studies the link between stock returns and size and book-to-market equity effects for 10 companies listed at the Suriname Stock Exchange. We analyze the cross-sectional variation in average returns and we find that there is apparently no size effect, but the

  9. Cobalt particle size effects in catalysis

    NARCIS (Netherlands)

    den Breejen, J.P.

    2010-01-01

    Aim of the work described in this thesis was first to investigate cobalt particle size effects in heterogeneous catalysis. The main focus was to provide a deeper understanding of the origin of the cobalt particle size effects in Fischer-Tropsch (FT) catalysis in which synthesis gas (H2/CO) is conver

  10. Effect size for dichotomous outcome measures

    Institute of Scientific and Technical Information of China (English)

    Yuanjia WANG; Naihua DUAN

    2011-01-01

    @@ Effect size for continuous outcome measures was discussed in our previous column[1].In this column we discuss several widely used effect size measures for dichotomous (Yes/No) outcome measures such as mortality,relapse,cure,discontinuation of treatment,and so forth.

  11. Cobalt particle size effects in catalysis

    NARCIS (Netherlands)

    den Breejen, J.P.

    2010-01-01

    Aim of the work described in this thesis was first to investigate cobalt particle size effects in heterogeneous catalysis. The main focus was to provide a deeper understanding of the origin of the cobalt particle size effects in Fischer-Tropsch (FT) catalysis in which synthesis gas (H2/CO) is

  12. Size and value effects in Suriname

    NARCIS (Netherlands)

    D.S. Bodeutsch (Denice); Ph.H.B.F. Franses (Philip Hans)

    2013-01-01

    markdownabstract__Abstract__ This paper studies the link between stock returns and size and book-to-market equity effects for 10 companies listed at the Suriname Stock Exchange. We analyze the cross-sectional variation in average returns and we find that there is apparently no size effect, but

  13. Effective population size of korean populations.

    Science.gov (United States)

    Park, Leeyoung

    2014-12-01

    Recently, new methods have been developed for estimating the current and recent changes in effective population sizes. Based on the methods, the effective population sizes of Korean populations were estimated using data from the Korean Association Resource (KARE) project. The overall changes in the population sizes of the total populations were similar to CHB (Han Chinese in Beijing, China) and JPT (Japanese in Tokyo, Japan) of the HapMap project. There were no differences in past changes in population sizes with a comparison between an urban area and a rural area. Age-dependent current and recent effective population sizes represent the modern history of Korean populations, including the effects of World War II, the Korean War, and urbanization. The oldest age group showed that the population growth of Koreans had already been substantial at least since the end of the 19th century.

  14. 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.

  15. 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 resistance...... to dislocation motion and to dislocation generation, respectively. It is shown that both strengthening mechanisms take place in some nanostructured metals, which leads to a suggestion to use these two mechanisms for optimizing the strength and ductility of nanostructured metals. This suggestion is verified...

  16. 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.

  17. Board Size Effects in Closely Held Corporations

    DEFF Research Database (Denmark)

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

    2004-01-01

    Previous work on board size effects in closely held corporationshas established a negative correlation between board size and firm performance.We argue that this work has been incomplete in analysing the causalrelationship due to lack of ownership information and weak identificationstrategies in ...

  18. Board Size Effects in Closely Held Corporations

    DEFF Research Database (Denmark)

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

    2004-01-01

    Previous work on board size effects in closely held corporationshas established a negative correlation between board size and firm performance.We argue that this work has been incomplete in analysing the causalrelationship due to lack of ownership information and weak identificationstrategies in ...

  19. Publication bias in psychology: a diagnosis based on the correlation between effect size and sample size

    National Research Council Canada - National Science Library

    Kühberger, Anton; Fritz, Astrid; Scherndl, Thomas

    2014-01-01

    .... 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...

  20. The association between retrospective outcome evaluations and pre-post-treatment changes in psychodynamic group-psychotherapy

    DEFF Research Database (Denmark)

    Jensen, Hans Henrik; Mortensen, Erik Lykke; Lotz, Martin

    2008-01-01

    In the present study of 203 patients in psychodynamic group psychotherapy, we explore associations between patient and therapist global retrospective outcome evaluations (ROE), and pre-post-treatment changes on the Symptom Check List 90 Revised (SCL-90-R) and non-symptomatic focus of therapy. The...

  1. Curriculum-Based Measurement of Oral Reading: Evaluation of Growth Estimates Derived with Pre-Post Assessment Methods

    Science.gov (United States)

    Christ, Theodore J.; Monaghen, Barbara D.; Zopluoglu, Cengiz; Van Norman, Ethan R.

    2013-01-01

    Curriculum-based measurement of oral reading (CBM-R) is used to index the level and rate of student growth across the academic year. The method is frequently used to set student goals and monitor student progress. This study examined the diagnostic accuracy and quality of growth estimates derived from pre-post measurement using CBM-R data. A…

  2. 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...

  3. Pre/post-closure assessment of groundwater pharmaceutical fate in a wastewater‑facility-impacted stream reach

    Science.gov (United States)

    Bradley, Paul M.; Barber, Larry B.; Clark, Jimmy M.; Duris, Joseph; Foreman, William; Furlong, Edward T.; Givens, Carrie E.; Hubbard, Laura E.; Hutchinson, Kasey J.; Journey, Celeste A.; Keefe, Steffanie H.; Kolpin, Dana W.

    2016-01-01

    Pharmaceutical contamination of contiguous groundwater is a substantial concern in wastewater-impacted streams, due to ubiquity in effluent, high aqueous mobility, designed bioactivity, and to effluent-driven hydraulic gradients. Wastewater treatment facility (WWTF) closures are rare environmental remediation events; offering unique insights into contaminant persistence, long-term wastewater impacts, and ecosystem recovery processes. The USGS conducted a combined pre/post-closure groundwater assessment adjacent to an effluent-impacted reach of Fourmile Creek, Ankeny, Iowa, USA. Higher surface-water concentrations, consistent surface-water to groundwater concentration gradients, and sustained groundwater detections tens of meters from the stream bank demonstrated the importance of WWTF effluent as the source of groundwater pharmaceuticals as well as the persistence of these contaminants under effluent-driven, pre-closure conditions. The number of analytes (110 total) detected in surface water decreased from 69 prior to closure down to 8 in the first post-closure sampling event approximately 30 d later, with a corresponding 2 order of magnitude decrease in the cumulative concentration of detected analytes. Post-closure cumulative concentrations of detected analytes were approximately 5 times higher in proximal groundwater than in surface water. About 40% of the 21 contaminants detected in a downstream groundwater transect immediately before WWTF closure exhibited rapid attenuation with estimated half-lives on the order of a few days; however, a comparable number exhibited no consistent attenuation during the year-long post-closure assessment. The results demonstrate the potential for effluent-impacted shallow groundwater systems to accumulate pharmaceutical contaminants and serve as long-term residual sources, further increasing the risk of adverse ecological effects in groundwater and the near-stream ecosystem.

  4. 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.

  5. 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 ...

  6. 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...

  7. Structural effect of size on interracial friendship

    OpenAIRE

    Cheng, Siwei; Xie, Yu

    2013-01-01

    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 co...

  8. Size effects on generation recombination noise

    OpenAIRE

    Gomila, G.; Reggiani, L.

    2002-01-01

    We carry out an analytical theory of generation-recombination noise for a two level resistor model which goes beyond those presently available by including the effects of both space charge fluctuations and diffusion current. Finite size effects are found responsible for the saturation of the low frequency current spectral density at high enough applied voltages. The saturation behaviour is controlled essentially by the correlations coming from the long range Coulomb interaction. It is suggest...

  9. The effect of particle size on fracture properties and size effect of concrete

    NARCIS (Netherlands)

    Schlangen, E.; Lim, H.S.; Weerheijm, J.

    2005-01-01

    In the study the effect of scaling the material structure on the fracture behaviour of concrete is investigated. Next to this the size effect of concrete fracture strength and fracture energy is studied. The fracture mechanism of concrete made with different size aggregates are tested numerically. A

  10. Using a transdiagnostic, psychodynamic online self-help intervention to maintain inpatient psychosomatic treatment effects: Study protocol of a feasibility study

    Directory of Open Access Journals (Sweden)

    Jan Becker

    2016-09-01

    Conclusion: We expect insight into the usefulness and acceptance of an online self-help intervention used to maintain inpatient treatment effects. Furthermore, we await both groups to benefit from the participation in the intervention. Pre- post and between subject differences will be used as estimate effect sizes to calculate the necessary sample size for a larger efficacy trial.

  11. Conductivity size effect of polycrystalline metal nanowires

    Directory of Open Access Journals (Sweden)

    Weihuang Xue

    2016-11-01

    Full Text Available It is well known that the conductivity of metal nanowires decreases with the wire diameter. This size effect was first studied for metal thin films when the film thickness approaches the electron mean free path. Fuchs & Sondheimer (FS pointed out that the external surface scattering of the electrons contributes to the conductivity decrease. Mayadas and Shatzkes (MS pointed out that the grain boundary scattering plays a major role for polycrystalline thin films. As is clear that nanowires are 2-d constrained instead of 1-d for thin film, so the size effect would be more eminent. However, today the mostly used physical model for the conductivity of metal nanowires is still the MS theory. This paper proposes a more complete model suitable for circular cross-section polycrystalline metal nanowires, which takes into account of background scattering, external surface scattering, as well as grain boundary scattering. Comparison with experiment data showed that our model can well explain the conductivity size effect of polycrystalline metal nanowires.

  12. Emergency department transfers and hospital admissions from residential aged care facilities: a controlled pre-post design study.

    Science.gov (United States)

    Hullick, Carolyn; Conway, Jane; Higgins, Isabel; Hewitt, Jacqueline; Dilworth, Sophie; Holliday, Elizabeth; Attia, John

    2016-05-12

    Older people living in Residential Aged Care Facilities (RACF) are a vulnerable, frail and complex population. They are more likely than people who reside in the community to become acutely unwell, present to the Emergency Department (ED) and require admission to hospital. For many, hospitalisation carries with it risks. Importantly, evidence suggests that some admissions are avoidable. A new collaborative model of care, the Aged Care Emergency Service (ACE), was developed to provide clinical support to nurses in the RACFs, allowing residents to be managed in place and avoid transfer to the ED. This paper examines the effects of the ACE service on RACF residents' transfer to hospital using a controlled pre-post design. Four intervention RACFs were matched with eight control RACFs based on number of total beds, dementia specific beds, and ratio of high to low care beds in Newcastle, Australia, between March and November 2011. The intervention consisted of a clinical care manual to support care along with a nurse led telephone triage line, education, establishing goals of care prior to ED transfer, case management when in the ED, along with the development of collaborative relationships between stakeholders. Outcomes included ED presentations, length of stay, hospital admission and 28-day readmission pre- and post-intervention. Generalised estimating equations were used to estimate mean differences in outcomes between intervention and controls RACFs, pre- and post-intervention means, and their interaction, accounting for repeated measures and adjusting for matching factors. Residents had a mean age of 86 years. ED presentations ranged between 16 and 211 visits/100 RACF beds/year across all RACFs. There was no overall reduction in ED presentations (OR = 1.17, p = 0.56) with the ACE intervention. However, when compared to the controls, the intervention group reduced their ED length of stay by 45 min (p = 0.0575), and was 40 % less likely to be admitted

  13. The size effect in metal cutting

    Indian Academy of Sciences (India)

    Milton C Shaw

    2003-10-01

    When metal is removed by machining there is substantial increase in the specific energy required with decrease in chip size. It is generally believed this is due to the fact that all metals contain defects (grain boundaries, missing and impurity atoms, etc.), and when the size of the material removed decreases, the probability of encountering a stress-reducing defect decreases. Since the shear stress and strain in metal cutting is unusually high, discontinuous microcracks usually form on the metal-cutting shear plane. If the material being cut is very brittle, or the compressive stress on the shear plane is relatively low, microcracks grow into gross cracks giving rise to discontinuous chip formation. When discontinuous microcracks form on the shear plane they weld and reform as strain proceeds, thus joining the transport of dislocations in accounting for the total slip of the shear plane. In the presence of a contaminant, such as CCl4 vapour at a low cutting speed, the rewelding of microcracks decreases, resulting in decrease in the cutting force required for chip formation. A number of special experiments are described in the paper that support the transport of microcracks across the shear plane, and the important role compressive stress plays on the shear plane. Relatively recently, an alternative explanation for the size effect in cutting was provided based on the premise that shear stress increases with increase in strain rate. When an attempt is made to apply this to metal cutting by Dinesh et al (2001) it is assumed in the analysis that the von Mises criterion pertains to the shear plane. This is inconsistent with the experimental findings of Merchant. Until this difficulty is taken care of, together with the promised experimental verification of the strain rate approach, it should be assumed that the strain rate effect may be responsible for some notion of the size effect in metal cutting. However, based on the many experiments discussed here, it is

  14. Size-effects in porous metals

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    . For porous materials with small void volume fractions under highly triaxial tension, void growth is analyzed through cavitation instabilities using a finite element Rayleigh-Ritz procedure. Cavitation instabilities are found to be delayed for small voids, so that higher stress levels are needed in order......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...... of relative void growth. The influence of void size compared to a constitutive length parameter is analyzed and it is shown that strain gradient hardening suppresses void growth on the micron scale. This increased resistance to void growth is accompanied by an increase in the overall strength of the material...

  15. 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...

  16. Impact of an Educational Intervention to Improve Physician Adherence to Bronchiolitis Clinical Practice Guidelines: A Pre-Post Intervention Study.

    Science.gov (United States)

    Genies, Marquita C; Kim, Julia M; Pyclik, Kristina; Rossi, Suzanne; Spicyn, Natalie; Serwint, Janet R

    2017-04-01

    Bronchiolitis is the leading cause of infant hospitalizations in the United States. Despite clinical practice guidelines discouraging the utilization of non-evidence-based therapies, there continues to be wide variation in care and resource utilization. A pre-post physician focused educational intervention was conducted with the aims to reduce the use of non-evidence-based medical therapies, including bronchodilators, among patients admitted for bronchiolitis. Among patients meeting inclusion criteria (pre: n = 45; post: n = 47), bronchodilator use decreased by 50% ( P educational intervention highlighting American Academy of Pediatrics clinical practice guidelines resulted in reduced utilization of bronchodilators.

  17. Size-effects in porous metals

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2007-01-01

    of the material. For porous materials with small void volume fractions under highly triaxial tension, void growth is analysed through cavitation instabilities using a finite element Rayleigh–Ritz procedure. Cavitation instabilities are found to be delayed for small voids, so that higher stress levels are needed......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...

  18. 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 i

  19. Size effects on miniature Stirling cycle cryocoolers

    Science.gov (United States)

    Yang, Xiaoqin; Chung, J. N.

    2005-08-01

    Size effects on the performance of Stirling cycle cryocoolers were investigated by examining each individual loss associated with the regenerator and combining these effects. For the fixed cycle parameters and given regenerator length scale, it was found that only for a specific range of the hydrodynamic diameter the system can produce net refrigeration and there is an optimum hydraulic diameter at which the maximum net refrigeration is achieved. When the hydraulic diameter is less than the optimum value, the regenerator performance is controlled by the pressure drop loss; when the hydraulic diameter is greater than the optimum value, the system performance is controlled by the thermal losses. It was also found that there exists an optimum ratio between the hydraulic diameter and the length of the regenerator that offers the maximum net refrigeration. As the regenerator length is decreased, the optimum hydraulic diameter-to-length ratio increases; and the system performance is increased that is controlled by the pressure drop loss and heat conduction loss. Choosing appropriate regenerator characteristic sizes in small-scale systems are more critical than in large-scale ones.

  20. Size effects on miniature Stirling cycle cryocoolers

    Energy Technology Data Exchange (ETDEWEB)

    Xiaoqin Yang; Chung, J.N. [Florida Univ., Dept. of Mechanical and Aerospace Engineering, Gainesville, FL (United States)

    2005-08-01

    Size effects on the performance of Stirling cycle cryocoolers were investigated by examining each individual loss associated with the regenerator and combining these effects. For the fixed cycle parameters and given regenerator length scale, it was found that only for a specific range of the hydrodynamic diameter the system can produce net refrigeration and there is an optimum hydraulic diameter at which the maximum net refrigeration is achieved. When the hydraulic diameter is less than the optimum value, the regenerator performance is controlled by the pressure drop loss; when the hydraulic diameter is greater than the optimum value, the system performance is controlled by the thermal losses. It was also found that there exists an optimum ratio between the hydraulic diameter and the length of the regenerator that offers the maximum net refrigeration. As the regenerator length is decreased, the optimum hydraulic diameter-to-length ratio increases; and the system performance is increased that is controlled by the pressure drop loss and heat conduction loss. Choosing appropriate regenerator characteristic sizes in small-scale systems are more critical than in large-scale ones. (Author)

  1. Publication bias in psychology: a diagnosis based on the correlation between effect size and sample size.

    Directory of Open Access Journals (Sweden)

    Anton Kühberger

    Full Text Available 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.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.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.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.

  2. 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

  3. Finite-size effects from giant magnons

    Energy Technology Data Exchange (ETDEWEB)

    Arutyunov, Gleb [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands)]. E-mail: g.arutyunov@phys.uu.nl; Frolov, Sergey [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, D-14476 Potsdam (Germany)]. E-mail: frolovs@aei.mpg.de; Zamaklar, Marija [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, D-14476 Potsdam (Germany)]. E-mail: marzam@aei.mpg.de

    2007-08-27

    In order to analyze finite-size effects for the gauge-fixed string sigma model on AdS{sub 5}xS{sup 5}, we construct one-soliton solutions carrying finite angular momentum J. In the infinite J limit the solutions reduce to the recently constructed one-magnon configuration of Hofman and Maldacena. The solutions do not satisfy the level-matching condition and hence exhibit a dependence on the gauge choice, which however disappears as the size J is taken to infinity. Interestingly, the solutions do not conserve all the global charges of the psu(2,2-vertical bar4) algebra of the sigma model, implying that the symmetry algebra of the gauge-fixed string sigma model is different from psu(2,2-vertical bar4) for finite J, once one gives up the level-matching condition. The magnon dispersion relation exhibits exponential corrections with respect to the infinite J solution. We also find a generalisation of our one-magnon configuration to a solution carrying two charges on the sphere. We comment on the possible implications of our findings for the existence of the Bethe ansatz describing the spectrum of strings carrying finite charges.

  4. Strong crystal size effect on deformation twinning

    DEFF Research Database (Denmark)

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

    2010-01-01

    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....... The sample size in transition is relatively large and easily accessible in experiments, making our understanding of size dependence11, 12, 13, 14, 15, 16, 17 relevant for applications....

  5. Power and sample size for the S:T repeated measures design combined with a linear mixed-effects model allowing for missing data.

    Science.gov (United States)

    Tango, Toshiro

    2017-02-13

    Tango (Biostatistics 2016) proposed a new repeated measures design called the S:T repeated measures design, combined with generalized linear mixed-effects models and sample size calculations for a test of the average treatment effect that depend not only on the number of subjects but on the number of repeated measures before and after randomization per subject used for analysis. The main advantages of the proposed design combined with the generalized linear mixed-effects models are (1) it can easily handle missing data by applying the likelihood-based ignorable analyses under the missing at random assumption and (2) it may lead to a reduction in sample size compared with the simple pre-post design. In this article, we present formulas for calculating power and sample sizes for a test of the average treatment effect allowing for missing data within the framework of the S:T repeated measures design with a continuous response variable combined with a linear mixed-effects model. Examples are provided to illustrate the use of these formulas.

  6. 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...... irrespective of their sizes, can, under some assumptions, result in higher size inequality than when competition is absent. We demonstrate our approach by applying it to data from a greenhouse experiment investigating the size symmetry of belowground competition between pairs of Triticum aestivum (wheat...

  7. Quantum size effects in spherical semiconductor microcrystals

    Science.gov (United States)

    Nair, Selvakumar V.; Sinha, Sucharita; Rustagi, K. C.

    1987-03-01

    The size dependence of the lowest electron-hole state in semiconductor microcrystals is calculated using the variational principle with a three-parameter Hylleraas-type wave function. For very small particles the Coulomb interaction may be treated as a perturbation. For larger particles the size dependence of the energy is much sharper than that expected in previous work.

  8. [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.

  9. Capacity-building and clinical competence in infectious disease in Uganda: a mixed-design study with pre/post and cluster-randomized trial components.

    Directory of Open Access Journals (Sweden)

    Marcia R Weaver

    Full Text Available TRIAL DESIGN: Best practices for training mid-level practitioners (MLPs to improve global health-services are not well-characterized. Two hypotheses were: 1 Integrated Management of Infectious Disease (IMID training would improve clinical competence as tested with a single arm, pre-post design, and 2 on-site support (OSS would yield additional improvements as tested with a cluster-randomized trial. METHODS: Thirty-six Ugandan health facilities (randomized 1∶1 to parallel OSS and control arms enrolled two MLPs each. All MLPs participated in IMID (3-week core course, two 1-week boost sessions, distance learning. After the 3-week course, OSS-arm trainees participated in monthly OSS. Twelve written case scenarios tested clinical competencies in HIV/AIDS, tuberculosis, malaria, and other infectious diseases. Each participant completed different randomly-assigned blocks of four scenarios before IMID (t0, after 3-week course (t1, and after second boost course (t2, 24 weeks after t1. Scoring guides were harmonized with IMID content and Ugandan national policy. Score analyses used a linear mixed-effects model. The primary outcome measure was longitudinal change in scenario scores. RESULTS: Scores were available for 856 scenarios. Mean correct scores at t0, t1, and t2 were 39.3%, 49.1%, and 49.6%, respectively. Mean score increases (95% CI, p-value for t0-t1 (pre-post period and t1-t2 (parallel-arm period were 12.1 ((9.6, 14.6, p<0.001 and -0.6 ((-3.1, +1.9, p = 0.647 percent for OSS arm and 7.5 ((5.0, 10.0, p<0.001 and 1.6 ((-1.0, +4.1, p = 0.225 for control arm. The estimated mean difference in t1 to t2 score change, comparing arm A (participated in OSS vs. arm B was -2.2 ((-5.8, +1.4, p = 0.237. From t0-t2, mean scores increased for all 12 scenarios. CONCLUSIONS: Clinical competence increased significantly after a 3-week core course; improvement persisted for 24 weeks. No additional impact of OSS was observed. Data on clinical practice

  10. Preventing the pack size effect: Exploring the effectiveness of pictorial and non-pictorial serving size recommendations

    NARCIS (Netherlands)

    Versluis, Iris; Papies, Esther; Marchiori, David

    2015-01-01

    People eat more from large than from small packs, which is known as the pack size effect. We hypothesized that providing a serving size recommendation would reduce the influence of the pack size on consumption and would thus diminish the pack size effect. Moreover, we hypothesized that a pictorial

  11. Preventing the pack size effect: Exploring the effectiveness of pictorial and non-pictorial serving size recommendations

    NARCIS (Netherlands)

    Versluis, Iris; Papies, Esther; Marchiori, David

    2015-01-01

    People eat more from large than from small packs, which is known as the pack size effect. We hypothesized that providing a serving size recommendation would reduce the influence of the pack size on consumption and would thus diminish the pack size effect. Moreover, we hypothesized that a pictorial s

  12. Publication Bias in Psychology: A Diagnosis Based on the Correlation between Effect Size and Sample Size: e105825

    National Research Council Canada - National Science Library

    Anton Kühberger; Astrid Fritz; Thomas Scherndl

    2014-01-01

    .... 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...

  13. 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…

  14. 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…

  15. Effect of Particle Size on Shear Stress of Magnetorheological Fluids

    Directory of Open Access Journals (Sweden)

    Chiranjit Sarkar

    2015-05-01

    Full Text Available Magnetorheological fluids (MRF, known for their variable shear stress contain magnetisable micrometer-sized particles (few micrometer to 200 micrometers in a nonmagnetic carrier liquid. To avoid settling of particles, smaller sized (3-10 micrometers particles are preferred, while larger sized particles can be used in MR brakes, MR clutches, etc. as mechanical stirring action in those mechanisms does not allow particles to settle down. Ideally larger sized particles provide higher shear stress compared to smaller sized particles. However there is need to explore the effect of particle sizes on the shear stress. In the current paper, a comparison of different particle sizes on MR effect has been presented. Particle size distributions of iron particles were measured using HORIBA Laser Scattering Particle Size Distribution Analyser. The particle size distribution, mean sizes and standard deviations have been presented. The nature of particle shapes has been observed using scanning electron microscopy. To explore the effect of particle sizes, nine MR fluids containing small, large and mixed sized carbonyl iron particles have been synthesized. Three concentrations (9%, 18% and 36% by volume for each size of particles have been used. The shear stresses of those MRF samples have been measured using ANTON PAAR MCR-102 Rheometer. With increase in volume fraction of iron particles, the MR fluids synthesized using “mixed sized particles” show better shear stress compared to the MR fluids containing “smaller sized spherical shaped particles” and “larger sized flaked shaped particles” at higher shear rate.

  16. A Dataset for Education-Related Majors' Performance Measures with Pre/Post-Video Game Practice

    Science.gov (United States)

    Novak, Elena; Tassell, Janet Lynne

    2015-01-01

    This dataset includes a series of 30 education-related majors' performance measures before and after they completed a 10-hour video game practice in a computer lab. The goal of the experimental study was to examine the effects of action video gaming on students' mathematics performance and mathematics anxiety as mediated by the effect of attention…

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

    Science.gov (United States)

    Heidel, R. Eric

    2016-01-01

    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. PMID:27073717

  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. Size effects of effective Young's modulus for periodic cellular materials

    Institute of Scientific and Technical Information of China (English)

    DAI GaoMing; ZHANG WeiHong

    2009-01-01

    With the wide demands of cellular materials applications in aerospace and civil engineering, research effort sacrificed for this type of materials attains nowadays a higher level than ever before. This paper is focused on the prediction methods of effective Young's modulus for periodical cellular materials. Based on comprehensive studies of the existing homogenization method (HM), the G-A meso-me-chanice method (G-A MMM) and the stretching energy method (SEM) that are unable to reflect the size effect, we propose the bending energy method (BEM) for the first time, and a comparative study of these four methods is further made to show the generality and the capability of capturing the size effect of the BEM method. Meanwhile, the underlying characteristics of each method and their relations are clarified. To do this, the detailed finite element computing and existing experimental results of hex-agonal honeycombs from the literature are adopted as the standard of comparison for the above four methods. Stretch and bending models of periodical cellular materials are taken into account, respec-tively for the comparison of stretch and flexural displacements resulting from the above methods. We conclude that the BEM has the strong ability of both predicting the effective Young's modulus and re- vealing the size effect. Such a method is also able to predict well the variations of structural displace-ments in terms of the cell size under stretching and bending loads including the non-monotonous variations for the hexagonal cell. On the contrary, other three methods can only predict the limited re- sults whenever the cell size tends to be infinitely small.

  1. Use of the Significance Test as a Protection against Spuriously High Standardized Effect Sizes: Introduction of the Protected Effect Size.

    Science.gov (United States)

    Barnette, J. Jackson; McLean, James E.

    The level of standardized effect sizes obtained by chance and the use of significance tests to guard against spuriously high standardized effect sizes were studied. The concept of the "protected effect size" is also introduced. Monte Carlo methods were used to generate data for the study using random normal deviates as the basis for sample means…

  2. 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…

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

    Science.gov (United States)

    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 it is not possible to generalize consumer behaviour across cultures, external cues taken from pack size may affect us all. We thus examined whether pack sizes influence portion size estimates across cultures, leading to a general 'pack size effect'. We compared portion size estimates based on digital presentations of different product pack sizes of solid and liquid products. The study with 13,177 participants across six European countries consisted of three parts. Parts 1 and 2 asked participants to indicate the number of portions present in a combined photographic and text-based description of different pack sizes. The estimated portion size was calculated as the quotient of the content weight or volume of the food presented and the number of stated portions. In Part 3, participants stated the number of food items that make up a portion when presented with packs of food containing either a small or a large number of items. The estimated portion size was calculated as the item weight times the item number. For all three parts and across all countries, we found that participants' portion estimates were based on larger portions for larger packs compared to smaller packs (Part 1 and 2) as well as more items to make up a portion (Part 3); hence, portions were stated to be larger in all cases. Considering that the larger estimated portions are likely to be consumed, there are implications for energy intake and weight status.

  4. 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.

  5. Size Effects in Heavy Ions Fragmentation

    CERN Document Server

    Barrañon, A; Dorso, C O

    2003-01-01

    Rise-Plateau Caloric curves for different Heavy Ion collisions have been obtained, in the range of experimental observations. Limit temperature decreases when the residual size is increased, in agreement with recent theoretical analysis of experimental results reported by other Collaborations. Besides, promptly emitted particles influence on temperature plateau is shown. LATINO binary interaction semiclassical model is used to reproduce the inter-nucleonic forces via Pandharipande Potential and fragments are detected with an Early Cluster Recognition Algorithm.

  6. Class Size and Teacher Effects in Higher Education

    OpenAIRE

    Gastón Illanes; Claudio Sapelli

    2012-01-01

    Using student evaluations as a learning measure, we estimate and compare class size and teacher effects for higher education, with emphasis on determining whether a comprehensive class size reduction policy that draws on the hiring of new teachers is likely to improve educational outcomes. We find that teacher effects far outweigh class size effects, and that young teachers and first time teachers perform significantly worse than their peers. Furthermore, we study whether teacher effects are ...

  7. Mastery learning improves students skills in inserting intravenous access: a pre-post-study

    Directory of Open Access Journals (Sweden)

    Friederichs, Hendrik

    2016-08-01

    Full Text Available Objective: Inserting peripheral venous catheters (PVCs has been identified as a core competency for medical students. Because the performance – even of hygienic standards – of both students and novice physicians is frequently inadequate, medical faculties must focus on competence-based learning objectives and deliberate practice, features that are combined in mastery learning. Our aim was to determine the competency of students in inserting PVCs before and after an educational intervention. Design: This study comprised a skills assessment with pre- and post-tests of a group of third-year students who received a simulation-based intervention. A newly established curriculum involved one hour of practice at inserting PVCs on simulators. Students were required to pass a test (total 21 points, pass mark 20 points developed on the concept of mastery learning. An unannounced follow-up test was performed one week (8 days after the intervention.Setting: The simulation center of the medical faculty in Muenster.Participants: Third-year students who received the intervention.Results: One hundred and nine complete data sets were obtained from 133 students (82.5%. Most students (97.2% passed the test after the intervention (mean score increase from 15.56 to 20.50, <0.001. There was a significant decrease in students’ performance after one week (8 days: only 74.5% of participants passed this retest (mean score reduction from 20.50 to 20.06, <0.001. Conclusion: Mastery learning is an effective form of teaching practical skills to medical students, allowing a thorough preparation for the challenges of daily clinical practice.

  8. Sample Size Calculations for Precise Interval Estimation of the Eta-Squared Effect Size

    Science.gov (United States)

    Shieh, Gwowen

    2015-01-01

    Analysis of variance is one of the most frequently used statistical analyses in the behavioral, educational, and social sciences, and special attention has been paid to the selection and use of an appropriate effect size measure of association in analysis of variance. This article presents the sample size procedures for precise interval estimation…

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

    Indian Academy of Sciences (India)

    Jin-Keun Kim; Seong-Tae Yi

    2002-08-01

    It is important to consider the effect of size when estimating the ultimate strength of a concrete member under various loading conditions. Well known as the size effect, the strength of a member tends to decrease when its size increases. Therefore, in view of recent increased interest in the size effect of concrete this research focuses on the size effect of two main classes of compressive strength of concrete: pure axial compressive strength and flexural compressive strength. First, fracture mechanics type size effect on the compressive strength of cylindrical concrete specimens was studied, with the diameter, and the height/diameter ratio considered as the main parameters. Theoretical and statistical analyses were conducted, and a size effect equation was proposed to predict the compressive strength specimens. The proposed equation showed good agreement with the existing test results for concrete cylinders. Second, the size, length, and depth variations of a flexural compressive member have been studied experimentally. A series of -shaped specimens subjected to axial compressive load and bending moment were tested. The shape of specimens and the test procedures used were similar to those by Hognestad and others. The test results are curve-fitted using Levenberg-Marquardt’s least squares method (LSM) to obtain parameters for the modified size effect law (MSEL) by Kim and co workers. The results of the analysis show that the effect of specimen size, length, and depth on ultimate strength is significant. Finally, more general parameters for MSEL are suggested.

  10. Learning to Work with Databases in Astronomy: Quantitative Analysis of Science Educators' and Students' Pre-/Post-Tests

    Science.gov (United States)

    Schwortz, Andria C.; Burrows, Andrea C.; Myers, Adam D.

    2015-01-01

    Astronomy is increasingly moving towards working with large databases, from the state-of-the-art Sloan Digital Sky Survey Data Release 10, to the historical Digital Access to a Sky Century at Harvard. Non-astronomy fields as well tend to work with large datasets, be it in the form of warehouse inventory, health trends, or the stock market. However very few fields explicitly teach students the necessary skills to analyze such data. The authors studied a matched set of 37 participants working with 200-entry databases in astronomy using Google Spreadsheets, with limited information about a random set of quasars drawn from SDSS DR5. Here the authors present the quantitative results from an eight question pre-/post-test, with questions designed to span Bloom's taxonomy, on both the topics of the skills of using spreadsheets, and the content of quasars. Participants included both Astro 101 summer students and professionals including in-service K-12 teachers and science communicators. All groups showed statistically significant gains (as per Hake, 1998), with the greatest difference between women's gains of 0.196 and men's of 0.480.

  11. Size effect in the strength of concrete structures

    Indian Academy of Sciences (India)

    B L Karihaloo; Q Z Xiao

    2002-08-01

    This paper reports on the range of applicability of the various size effect formulae available in the literature. In particular, the failure loads of three point bend (TPB) beams are analysed according to the size effect formulae of Ba$\\breve{z}$ant and of Karihaloo for notched beams and according to those of Ba$\\breve{z}$ant and of Carpinteri for unnotched beams, and the results of this analysis presented. Improvements to Karihaloo’s size effect formula are also proposed.

  12. Size effect on compressive strength of reactive powder concrete

    Institute of Scientific and Technical Information of China (English)

    AN Ming-zhe; ZHANG Li-jun; YI Quan-xin

    2008-01-01

    In this paper the coefficient and law of the size effect of RPC were studied through experiments and theoretical analysis. The size-effect coefficients for the compressive strength of RPC are deduced through experiments. They indicate that RPC without fiber behaves quite the same as normal or high strength concrete. The size effect on compressive strength is more prominent in RPC containing fiber. Bazant's size effect formula of compressive strength applies to RPC. A formula is given to predict the compressive strength of cubic RPC specimens 100 mm on a side where the fiber dosage ranges from 0-2%.

  13. Size Effect for Normal Strength Concrete in Uniaxial Tension

    Institute of Scientific and Technical Information of China (English)

    李庆斌; 尹玉先

    2004-01-01

    This paper presents a new size effect model for normal strength concrete subjected to uniaxial tension. The model is based on two extremes, sand cement paste in uniaxial tension and a sand-cement-paste/rock interface in uniaxial tension. Uniaxial tension tests with normal strength concrete measuring the tensile strength of normal strength concrete specimens with different geometrical shapes and different ratios of the aggregate size to the characteristic dimension of the concrete specimen show a significant size effect. The theoretical size effect law prediction agrees well with the experimental data.

  14. Friction related size-effect in microforming – a review

    Directory of Open Access Journals (Sweden)

    Wang Chunju

    2014-01-01

    Full Text Available This paper presents a thorough literature review of the size effects of friction in microforming. During miniaturization, the size effects of friction occur clearly. The paper first introduces experimental research progress on size effects of friction in both micro bulk and sheet forming. The effects of several parameters are discussed. Based on the experimental results, several approaches have been performed to develop a model or functions to analyse the mechanism of size effects of friction, and simulate the micro deep drawing process by integrating them into an FE program. Following this, surface modification, e.g. a DLC film and a micro structure/textured surface, as a method to reduce friction are presented. Finally, the outlook for the size effect of friction in the future is assessed, based on the understanding of the current research progress.

  15. Quantum size effects in InP inner film fiber

    Institute of Scientific and Technical Information of China (English)

    WANG Ting-yun; WANG Ke-xin; LU Jun

    2005-01-01

    Based on the semiconductor amplifiing properties and the structure of optical fiber wave guide an InP inner fiber is developed.The InP inner film fiber can be employed as a small size,broadband,and ultra-short fiber amplifier.The quantum size effects of the fiber are emphatically investigated in the work.Using the experimental data,we compare the effective mass approximation (EMA) with effective parameterization within the tight binding (EPTB) models for the accurate description of the quantum size effects in InP.The results show that the EPTB model provides an excellent description of band gap variation over a wide range of sizes.The Bohr diameter and the effective Rydberg energy of InP are calculated.Finally,the amplifiing properties of the InP inner film fiber are discussed due to the quantum size effects.

  16. Can A Complex Online Intervention Improve Cancer Nurses' Pain Screening and Assessment Practices? Results from a Multicenter, Pre-post Test Pilot Study.

    Science.gov (United States)

    Phillips, Jane L; Heneka, Nicole; Hickman, Louise; Lam, Lawrence; Shaw, Tim

    2017-04-01

    Unrelieved cancer pain has an adverse impact on quality of life. While routine screening and assessment forms the basis of effective cancer pain management, it is often poorly done, thus contributing to the burden of unrelieved cancer pain. The aim of this study was to test the impact of an online, complex, evidence-based educational intervention on cancer nurses' pain assessment capabilities and adherence to cancer pain screening and assessment guidelines. Specialist inpatient cancer nurses in five Australian acute care settings participated in an intervention combining an online spaced learning cancer pain assessment module with audit and feedback of pain assessment practices. Participants' self-perceived pain assessment competencies were measured at three time points. Prospective, consecutive chart audits were undertaken to appraise nurses' adherence with pain screening and assessment guidelines. The differences in documented pre-post pain assessment practices were benchmarked and fed back to all sites post intervention. Data were analyzed using inferential statistics. Participants who completed the intervention (n = 44) increased their pain assessment knowledge, assessment tool knowledge, and confidence undertaking a pain assessment (p nurses' pain assessment capabilities translated into a significant increasing linear trend in the proportion of documented pain assessments in patients' charts at the three time points (χ(2) trend = 18.28, df = 1, p pain assessment audit and feedback data, improves inpatient cancer nurses' self-perceived pain screening and assessment capabilities and strengthens cancer pain guideline adherence. Copyright © 2017 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  17. Impact of implementing electronic clinical practice guidelines for the diagnosis, control and treatment of cardiovascular risk factors: A pre-post controlled study.

    Science.gov (United States)

    Comin, Eva; Catalan-Ramos, Arantxa; Iglesias-Rodal, Manuel; Grau, Maria; Del Val, Jose Luis; Consola, Alicia; Amado, Ester; Pons, Angels; Mata-Cases, Manel; Franzi, Alicia; Ciurana, Ramon; Frigola, Eva; Cos, Xavier; Davins, Josep; Verdu-Rotellar, Jose M

    To evaluate the impact of computerized clinical practice guidelines on the management, diagnosis, treatment, control, and follow-up of the main cardiovascular risk factors: hypertension, hypercholesterolaemia, and type 2 diabetes mellitus. Pre-post controlled study. Catalonia, autonomous community located in north-eastern Spain. Individuals aged 35-74 years assigned to general practitioners of the Catalan Health Institute. The intervention group consisted of individuals whose general practitioners had accessed the computerized clinical practice guidelines at least twice a day, while the control group consisted of individuals whose general practitioner had never accessed the computerized clinical practice guidelines platform. The Chi-squared test was used to detect significant differences in the follow-up, control, and treatment variables for all three disorders (hypertension, hypercholesterolaemia, and type 2 diabetes mellitus) between individuals assigned to users and non-users of the computerized clinical practice guidelines, respectively. A total of 189,067 patients were included in this study, with a mean age of 56 years (standard deviation 12), and 55.5% of whom were women. Significant differences were observed in hypertension management, treatment and control; type 2 diabetes mellitus management, treatment and diagnoses, and the management and control of hypercholesterolaemia in both sexes. Computerized clinical practice guidelines are an effective tool for the control and follow-up of patients diagnosed with hypertension, type 2 diabetes mellitus, and hypercholesterolaemia. The usefulness of computerized clinical practice guidelines to diagnose and adequately treat individuals with these disorders remains unclear. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  18. An Effect Size for Regression Predictors in Meta-Analysis

    Science.gov (United States)

    Aloe, Ariel M.; Becker, Betsy Jane

    2012-01-01

    A new effect size representing the predictive power of an independent variable from a multiple regression model is presented. The index, denoted as r[subscript sp], is the semipartial correlation of the predictor with the outcome of interest. This effect size can be computed when multiple predictor variables are included in the regression model…

  19. The impact of evidence-based sepsis guidelines on emergency department clinical practice: a pre-post medical record audit.

    Science.gov (United States)

    Romero, Bernadine; Fry, Margaret; Roche, Michael

    2017-01-10

    To explore the number of patients presenting with sepsis before and after guideline implementation; the impact of sepsis guidelines on triage assessment, emergency department management and time to antibiotics. Sepsis remains one of the leading causes of mortality and morbidity within hospitals. Globally, strategies have been implemented to reduce morbidity and mortality rates, which rely on the early recognition and management of sepsis. To improve patient outcomes, the New South Wales government in Australia introduced sepsis guidelines into emergency departments. However, the impact of the guidelines on clinical practice remains unclear. A 12-month pre-post retrospective randomised medical record audit of adult patients with a sepsis diagnosis. Data were extracted from the emergency department database and paper medical record. Data included patient demographic (age, gender), clinical information (time of arrival, triage code, seen by time, disposition, time to antibiotic, pathology, time to intravenous fluids) and patient assessment data (heart rate, respiratory rate, blood pressure, temperature, oxygen saturations, medication). This study demonstrated a statistically significant 230-minute reduction in time to antibiotics post implementation of the guidelines. The post group (n = 165) received more urgent triage categories (n = 81; 49·1%), a 758-minute reduction in mean time to second litre of intravenous fluids and an improvement in collection of lactate (n = 112, 67·9%), also statistically significant. The findings highlight the impact the guidelines can have on clinician decision-making and behaviour that support best practice and positive patient outcomes. The sepsis guidelines improved the early assessment, recognition and management of patients presenting with sepsis in one tertiary referral emergency department. The use of evidenced-based guidelines can impact clinical decision-making and behaviour, resulting in the translation and support of

  20. Size Effects in Linear Elastic Fracture Mechanics

    Science.gov (United States)

    1988-01-01

    Recent Theoretical and Experimental Developments in Fracture Mechanics", Fracture 1977, 1 (1977) 695-723. 40 S. Mindess and J. S. Nadeau," Effect of Notch...0.4 1.42 b 2.0 0.80 b Mindess and Nadeau [40], 1.0 3.98 0.86 b Mortar, 3PB 8.03 0.80 b 12.0 0.82 b 16.0 0.84 b 20.0 0.83 b Concrete, 3PB 1.0 3.54 1.08

  1. EFFECT OF SOYBEAN SEED SIZE ON SEED QUALITY

    Directory of Open Access Journals (Sweden)

    Atin Yulyatin

    2015-07-01

    Full Text Available Soybean seed is a seed that is rapidly deteriorate or decrease in viability and vigor, especially if stored in conditions that are less optimum savings. Soybean seed size can affect the quality of the seed. Seed quality is characterized by germination of seeds. Grain size effect on soybean utilization. Large seed size tends to be used as an industrial raw material utilization while small seed size as a seed planted back. Purpose of this study was to determine whether soybean seed size can affect the quality of the seeds while in storage. The experimental design used a Completely Randomized Design (CRD using soybean seed size is a large size (Grobogan, medium (Kaba, and small (Willis is repeated four times. Parameter observations are normal seeds, dirt seed, weight of 100 grains, moisture content, germination. Data were tabulated and analyzed using the F test, if significantly different then tested further by DMRT level of 5 percent. Large size seed has the normal number of seeds, seed dirt, moisture content higher than medium and small seed size. But has a lower germination than seeds of medium and small size. To maintain the water content of <11 percent should be larger seed size is more frequent than the dried seed medium and small sizes.

  2. Size effect on the static behavior of electrostatically actuated microbeams

    Institute of Scientific and Technical Information of China (English)

    Li Yin; Qin Qian; Lin Wang

    2011-01-01

    We present a new analytical model for electrostatically actuated microbeams to explore the size effect by using the modified couple stress theory and the minimum total potential energy principle. A material length scale parameter is introduced to represent the size-dependent characteristics of microbeams. This model also accounts for the nonlinearities associated with the mid-plane stretching force and the electrostatical force. Numerical analysis for microbeams with clamped-clamped and cantilevered conditions has been performed. It is found that the intensity of size effect is closely associated with the thickness of the microbeam, and smaller beam thickness displays stronger size effect and hence yields smaller deflection and larger pull-in voltage. When the beam thickness is comparable to the material length scale parameter, the size effect is significant and the present theoretical model including the material length scale parameter is adequate for predicting the static behavior of microbeam-based MEMS.

  3. Size effect of sandstone after high temperature under uniaxial compression

    Institute of Scientific and Technical Information of China (English)

    SU Hai-jian; JING Hong-wen; MAO Xian-biao; ZHAO Hong-hui; YIN Qian; WANG Chen

    2015-01-01

    Uniaxial compression tests on sandstone samples with five different sizes after high temperature processes were performed in order to investigate the size effect and its evolution. The test results show that the density, longitudinal wave velocity, peak strength, average modulus and secant modulus of sandstone decrease with the increase of temperature, however, peak strain increases gradually. With the increase of ratio of height to diameter, peak strength of sandstone decreases, which has an obvious size effect. A new theoretical model of size effect of sandstone material considering the influence of temperature is put forward, and with the increase of temperature, the size effect is more apparent. The threshold decreases gradually with the increase of temperature, and the deviations of the experimental values and the theoretical values are between 0.44% and 6.06%, which shows quite a credibility of the theoretical model.

  4. Effects of Titanium Dioxide Nanoparticle Aggregate Size on Gene Expression

    Directory of Open Access Journals (Sweden)

    Junko Okuda-Shimazaki

    2010-06-01

    Full Text Available Titanium dioxide (titania nanoparticle aggregation is an important factor in understanding cytotoxicity. However, the effect of the aggregate size of nanoparticles on cells is unclear. We prepared two sizes of titania aggregate particles and investigated their biological activity by analyzing biomarker expression based on mRNA expression analysis. The aggregate particle sizes of small and large aggregated titania were 166 nm (PDI = 0.291 and 596 nm (PDI = 0.417, respectively. These two size groups were separated by centrifugation from the same initial nanoparticle sample. We analyzed the gene expression of biomarkers focused on stress, inflammation, and cytotoxicity. Large titania aggregates show a larger effect on cell viability and gene expression when compared with the small aggregates. This suggests that particle aggregate size is related to cellular effects.

  5. Effect sizes for research univariate and multivariate applications

    CERN Document Server

    Grissom, Robert J

    2005-01-01

    The goal of this book is to inform a broad readership about a variety of measures and estimators of effect sizes for research, their proper applications and interpretations, and their limitations. Its focus is on analyzing post-research results. The book provides an evenhanded account of controversial issues in the field, such as the role of significance testing. Consistent with the trend toward greater use of robust statistical methods, the book pays much attention to the statistical assumptions of the methods and to robust measures of effect size.Effect Sizes for Research

  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 ...... 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. Effect of bubble size on nanofiber diameter in bubble electrospinning

    Directory of Open Access Journals (Sweden)

    Ren Zhong-Fu

    2016-01-01

    Full Text Available Polymer bubbles are widely used for fabrication of nanofibers. Bubble size affects not only bubble's surface tension, but also fiber's morphology. A mathematical model is established to reveal the effect of bubble size on the spinning process, and the experiment verification shows the theoretical analysis is reliable.

  8. QUANTUM SIZE EFFECTS IN THE ATTRACTIVE HUBBARD-MODEL

    NARCIS (Netherlands)

    BORMANN, D; SCHNEIDER, T; FRICK, M

    1992-01-01

    We investigate superconducting pair correlations in the attractive Hubbard model on a finite square lattice. Our aim is to understand the pronounced size dependence which they display in the weak and intermediate coupling regimes. These size effects originate from the electronic shell structure of f

  9. A Practical Method of Policy Analysis by Estimating Effect Size

    Science.gov (United States)

    Phelps, James L.

    2011-01-01

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

  10. 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.

  11. Finite-size effects in silica: a landscape perspective

    Energy Technology Data Exchange (ETDEWEB)

    Saksaengwijit, A; Heuer, A [Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Physikalische Chemie and International Graduate School of Chemistry, Corrensstrasse 30, 48149 Muenster (Germany)

    2007-05-23

    Finite-size effects are analysed for the well-known BKS model of silica. Results are presented for thermodynamic as well as dynamic observables which play a key role in the analysis of the potential energy landscape. It turns out that, for the analysed temperature range (T{>=}3000 K), a system with only N = 99 particles does not display significant finite-size effects in thermodynamic observables. In agreement with previous work, one observes finite-size effects for the dynamics. However, after rescaling of time the finite-size effects nearly disappear. These results suggest that for BKS-silica a system with only N = 99 particles is sufficiently large to study important properties of structural relaxation in the temperature range considered.

  12. Effects of Data Frame Size Distribution on Wireless Lans | Aneke ...

    African Journals Online (AJOL)

    Effects of Data Frame Size Distribution on Wireless Lans. ... Nigerian Journal of Technology ... to replace cables and deploy mobile devices in the communications industry has led to very active research on the utilization of wireless networks.

  13. Montelukast in Adenoid Hypertrophy: Its Effect on Size and Symptoms

    Directory of Open Access Journals (Sweden)

    Farshid Shokouhi

    2015-11-01

    Conclusion:  Montelukast chewable tablets achieved a significant reduction in adenoid size and improved the related clinical symptoms of AH and can therefore be considered an effective alternative to surgical treatment in children with adenoid hypertrophy.

  14. Cohesive stresses and size effect in quasi-brittle materials

    Indian Academy of Sciences (India)

    V E Saouma; D Natekar

    2002-08-01

    A novel approach to the derivation of Ba$\\breve{z}$ant’s size effect law is presented. Contrarily to the original Lagrangian derivation which hinged on energetic consideration, a Newtonian approach based on local stress intensity factors is presented. Through this approach, it is shown that Ba$\\breve{z}$ant’s size effect law is the first (and dominant) term in a series expansion for the nominal stress. Furthermore, analytical expressions for are derived for selected specimen geometries.

  15. Chemical effects of size quantization of CdS nanoparticles

    Institute of Scientific and Technical Information of China (English)

    陈德文; 王素华

    1996-01-01

    The behaviour of photoreaction occurring on the superfine duster interface of semiconductor CdS has been studied. The results indicated that the size quantization effect of semiconductor nanoparticles was obviously reflected not only in their physical properties, but also in the interfacial photocatalysis reactions initiated by superfine nanopartides. This means that the direction and mechanisms in photoreactions of the compounds adsorbed on the surface of nanopartides could vary with the alteration of particle size because the redox potential values of semiconductor particles could be changed with the variation of particle size. Doubtlessly, this effect could play an important role in controlling the interfacial reaction mechanisms and raising the selectivity to photoreaction paths.

  16. Study of size effect using digital image correlation

    Directory of Open Access Journals (Sweden)

    A. H. A. SANTOS

    Full Text Available Size effect is an important issue in concrete structures bearing in mind that it can influence many aspects of analysis such as strength, brittleness and structural ductility, fracture toughness and fracture energy, among others. Further this, ever more new methods are being developed to evaluate displacement fields in structures. In this paper an experimental evaluation of the size effect is performed applying Digital Image Correlation (DIC technique to measure displacements on the surface of beams. Three point bending tests were performed on three different size concrete beams with a notch at the midspan. The results allow a better understanding of the size effect and demonstrate the efficiency of Digital Image Correlation to obtain measures of displacements.

  17. Enhanced oxidation resistance of active nanostructures via dynamic size effect

    Science.gov (United States)

    Liu, Yun; Yang, Fan; Zhang, Yi; Xiao, Jianping; Yu, Liang; Liu, Qingfei; Ning, Yanxiao; Zhou, Zhiwen; Chen, Hao; Huang, Wugen; Liu, Ping; Bao, Xinhe

    2017-02-01

    A major challenge limiting the practical applications of nanomaterials is that the activities of nanostructures (NSs) increase with reduced size, often sacrificing their stability in the chemical environment. Under oxidative conditions, NSs with smaller sizes and higher defect densities are commonly expected to oxidize more easily, since high-concentration defects can facilitate oxidation by enhancing the reactivity with O2 and providing a fast channel for oxygen incorporation. Here, using FeO NSs as an example, we show to the contrary, that reducing the size of active NSs can drastically increase their oxidation resistance. A maximum oxidation resistance is found for FeO NSs with dimensions below 3.2 nm. Rather than being determined by the structure or electronic properties of active sites, the enhanced oxidation resistance originates from the size-dependent structural dynamics of FeO NSs in O2. We find this dynamic size effect to govern the chemical properties of active NSs.

  18. On the repeated measures designs and sample sizes for randomized controlled trials.

    Science.gov (United States)

    Tango, Toshiro

    2016-04-01

    For the analysis of longitudinal or repeated measures data, generalized linear mixed-effects models provide a flexible and powerful tool to deal with heterogeneity among subject response profiles. However, the typical statistical design adopted in usual randomized controlled trials is an analysis of covariance type analysis using a pre-defined pair of "pre-post" data, in which pre-(baseline) data are used as a covariate for adjustment together with other covariates. Then, the major design issue is to calculate the sample size or the number of subjects allocated to each treatment group. In this paper, we propose a new repeated measures design and sample size calculations combined with generalized linear mixed-effects models that depend not only on the number of subjects but on the number of repeated measures before and after randomization per subject used for the analysis. The main advantages of the proposed design combined with the generalized linear mixed-effects models are (1) it can easily handle missing data by applying the likelihood-based ignorable analyses under the missing at random assumption and (2) it may lead to a reduction in sample size, compared with the simple pre-post design. The proposed designs and the sample size calculations are illustrated with real data arising from randomized controlled trials.

  19. 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.

  20. Confidence Intervals for Standardized Effect Sizes: Theory, Application, and Implementation

    Directory of Open Access Journals (Sweden)

    Ken Kelley

    2007-02-01

    Full Text Available The behavioral, educational, and social sciences are undergoing a paradigmatic shift in methodology, from disciplines that focus on the dichotomous outcome of null hypothesis significance tests to disciplines that report and interpret effect sizes and their corresponding confidence intervals. Due to the arbitrariness of many measurement instruments used in the behavioral, educational, and social sciences, some of the most widely reported effect sizes are standardized. Although forming confidence intervals for standardized effect sizes can be very beneficial, such confidence interval procedures are generally difficult to implement because they depend on noncentral t, F, and x2 distributions. At present, no main-stream statistical package provides exact confidence intervals for standardized effects without the use of specialized programming scripts. Methods for the Behavioral, Educational, and Social Sciences (MBESS is an R package that has routines for calculating confidence intervals for noncentral t, F, and x2 distributions, which are then used in the calculation of exact confidence intervals for standardized effect sizes by using the confidence interval transformation and inversion principles. The present article discusses the way in which confidence intervals are formed for standardized effect sizes and illustrates how such confidence intervals can be easily formed using MBESS in R.

  1. Increasing use of mental health services in remote areas using mobile technology: a pre-post evaluation of the SMART Mental Health project in rural India.

    Science.gov (United States)

    Maulik, Pallab K; Kallakuri, Sudha; Devarapalli, Siddhardha; Vadlamani, Vamsi Krishna; Jha, Vivekanand; Patel, Anushka

    2017-06-01

    About 25% of the Indian population experience common mental disorders (CMD) but only 15-25% of them receive any mental health care. Stigma, lack of adequate mental health professionals and mental health services account for this treatment gap, which is worse in rural areas. Our project evaluated task shifting and mobile-technology based electronic decision support systems to enhance the ability of primary care health workers to provide evidence-based mental health care for stress, depression, and suicidal risk in 30 remote villages in the state of Andhra Pradesh, India. The Systematic Medical Appraisal Referral and Treatment (SMART) Mental Health project between May 2014 and April 2016 trained lay village health workers (Accredited Social Health Activists - ASHAs) and primary care doctors to screen, diagnose and manage individuals with common mental disorders using an electronic decision support system. An anti-stigma campaign using multi-media approaches was conducted across the villages at the outset of the project. A pre-post evaluation using mixed methods assessed the change in mental health service utilization by screen positive individuals. This paper reports on the quantitative aspects of that evaluation. Training was imparted to 21 ASHAs and 2 primary care doctors. 5007 of 5167 eligible individuals were screened, and 238 were identified as being positive for common mental disorders and referred to the primary care doctors for further management. Out of them, 2 (0.8%) had previously utilized mental health services. During the intervention period, 30 (12.6%) visited the primary care doctor for further diagnosis and treatment, as advised. There was a significant reduction in the depression and anxiety scores between start and end of the intervention among those who had screened positive at the beginning. Stigma and mental health awareness in the broader community improved during the project. The intervention led to individuals being screened for common mental

  2. Effect of stimulus check size on multifocal visual evoked potentials.

    Science.gov (United States)

    Balachandran, Chandra; Klistorner, Alexander I; Graham, Stuart L

    2003-03-01

    In this study we examined the effects of varying stimulus check size on multifocal visual evoked potential (VEP). We also evaluated the currently used cortical scaling of stimulus segments. The ObjectiVision multifocal objective perimeter stimulates the eye with random check patterns at 56 cortically scaled segments within the visual field extending to a radius of 26 degrees. All cortically scaled segments have equal number of checks, which gradually increase in size from the center to the periphery, proportional to the size of the segment. Stimuli with 9, 16, 25, 36 and 49 checks/segment were tested on 10 eyes belonging to 10 normal subjects. The check size varied inversely with number of checks per segment. VEP was recorded using bipolar occipital cross electrodes (7 min/eye), the amplitude and latency of responses obtained were compared with the check size at different eccentricities. Our findings suggest that the existing setting with 16 checks/segment subtending 26' to 140' from center to periphery, is the most effective amongst all the check sizes. Decreasing the check size prolongs the latency in the central field only. Cortical scaling of segments generates responses of the same order of magnitude throughout the field, but could be improved slightly to enhance the signal from the outer two rings.

  3. Origin of size effect on efficiency of organic photovoltaics

    DEFF Research Database (Denmark)

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

    2011-01-01

    on the voltage dependence of photocurrent and dark current is the key to understanding size limitation of the organic photovoltaics (OPV) efficiency. Practical methods to overcome this limitation as well as the possibility of producing concentrator OPV cells operating under sunlight concentrations higher than 10......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 solar...... cells of various sizes and suggest that the origin of both the size and the light intensity effects should include underlying physical mechanisms other than conventional series resistance dissipation. In particular, we conclude that the distributed nature of the ITO resistance and its influence...

  4. Size and shape effects on Curie temperature of ferromagnetic nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simplified model was developed to describe the Curie temperature suppression of ferromagnetic nanoparticles. Based on a size and shape dependent model of cohesive energy, the critical temperature variations of ferromagnetic nanoparticles were deduced. It is predicted that the Curie temperature of nanoparticles depends on both size and shape conditions, among which the temperature suppression is strongly influenced by the particle size and the shape effect is comparably minor. The calculation values for freestanding nanoparticles are in good agreement with other theoretical model and the experimental results. The model is also potential for predictions for the nanoparticles embedded in different substrates.

  5. Thermophoresis of microemulsion droplets: size dependence of the Soret effect.

    Science.gov (United States)

    Vigolo, Daniele; Brambilla, Giovanni; Piazza, Roberto

    2007-04-01

    Thermophoresis, akin to thermal diffusion in simple fluid mixtures, consists of particle drift induced by a temperature gradient. Notwithstanding its practical interest, the dependence of thermophoretic effects on particle size R is still theoretically and experimentally debated. By performing measurements of water-in-oil microemulsion droplets with tunable size, we show that the thermal diffusion coefficient, at least for a suspension of small particles in a nonpolar solvent, does not appreciably depend on R .

  6. Effects of Class Size on Alternative Educational Outcomes across Disciplines

    Science.gov (United States)

    Cheng, Dorothy A.

    2011-01-01

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

  7. Experimental Effects on IR Reflectance Spectra: Particle Size and Morphology

    Energy Technology Data Exchange (ETDEWEB)

    Beiswenger, Toya N.; Myers, Tanya L.; Brauer, Carolyn S.; Su, Yin-Fong; Blake, Thomas A.; Ertel, Alyssa B.; Tonkyn, Russell G.; Szecsody, James E.; Johnson, Timothy J.; Smith, Milton; Lanker, Cory

    2016-05-23

    For geologic and extraterrestrial samples it is known that both particle size and morphology can have strong effects on the species’ infrared reflectance spectra. Due to such effects, the reflectance spectra cannot be predicted from the absorption coefficients alone. This is because reflectance is both a surface as well as a bulk phenomenon, incorporating both dispersion as well as absorption effects. The same spectral features can even be observed as either a maximum or minimum. The complex effects depend on particle size and preparation, as well as the relative amplitudes of the optical constants n and k, i.e. the real and imaginary components of the complex refractive index. While somewhat oversimplified, upward-going amplitude in the reflectance spectrum usually result from surface scattering, i.e. rays that have been reflected from the surface without penetration, whereas downward-going peaks are due to either absorption or volume scattering, i.e. rays that have penetrated or refracted into the sample interior and are not reflected. While the effects are well known, we report seminal measurements of reflectance along with quantified particle size of the samples, the sizing obtained from optical microscopy measurements. The size measurements are correlated with the reflectance spectra in the 1.3 – 16 micron range for various bulk materials that have a combination of strong and weak absorption bands in order to understand the effects on the spectral features as a function of the mean grain size of the sample. We report results for both sodium sulfate Na2SO4 as well as ammonium sulfate (NH4)2SO4; the optical constants have been measured for (NH4)2SO4. To go a step further from the field to the laboratory we explore our understanding of particle size effects on reflectance spectra in the field using standoff detection. This has helped identify weaknesses and strengths in detection using standoff distances of up 160 meters away from the Target. The studies have

  8. Modeling size effect in the SMA response: a gradient theory

    Science.gov (United States)

    Tabesh, Majid; Boyd, James G.; Lagoudas, Dimitris C.

    2014-03-01

    Shape memory alloys (SMAs) show size effect in their response. The critical stresses, for instance, for the start of martensite and austenite transformations are reported to increase in some SMA wires for diameters below 100 μm. Simulation of such a behavior cannot be achieved using conventional theories that lack an intrinsic length scale in their constitutive modeling. To enable the size effect, a thermodynamically consistent constitutive model is developed, that in addition to conventional internal variables of martensitic volume fraction and transformation strain, contains the spatial gradient of martensitic volume fraction as an internal variable. The developed theory is simplified for 1D cases and analytical solutions for pure bending of SMA beams are presented. The gradient model captures the size effect in the response of the studied SMA structures.

  9. The Size Effects on Process Design of Micro Deep Drawing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper suggested to reformulate cylindrical deep drawing parameters with dimensionless form. A diagram, in which a feasible zone is drawn to bound both the maximal allowable tension and compression stress during the deep drawing process, was established. Since it is presented in a dimensionless form, it may be applied for both conventional and micro deep drawing. Cylindrical cup deep drawing was taken as an example to show the dimensionless process design method. In addition, the size effects should be taken into account. Two kinds of size effects on micro deep drawing were investigated, which can be explained by surface layer model and strain gradient model. Numerical simulations were carried out to compare the strain distribution with or without consideration of size effect.

  10. Effects of cell size on compressive properties of aluminum foam

    Institute of Scientific and Technical Information of China (English)

    CAO Xiao-qing; WANG Zhi-hua; MA Hong-wei; ZHAO Long-mao; YANG Gui-tong

    2006-01-01

    The effects of cell size on the quasi-static and dynamic compressive properties of open cell aluminum foams produced by infiltrating process were studied experimentally. The quasi-static and dynamic compressive tests were carried out on MTS 810 system and SHPB(split Hopkinson pressure bar) respectively. It is found that the elastic moduli and compressive strengths of the studied aluminum foam are not only dependent on the relative density but also dependent on the cell size of the foam under both quasi-static loading and dynamic loading. The foams studied show a significant strain rate sensitivity, the flow strength can be improved as much as 112%, and the cell size also has a sound influence on the strain rate sensitivity of the foams. The foams of middle cell size exhibit the highest elastic modulus, the highest flow strength and the most significant strain rate sensitivity.

  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. Simulation of grain size effects in nanocrystalline shape memory alloys

    Science.gov (United States)

    Ahluwalia, Rajeev; Quek, Siu Sin; Wu, David T.

    2015-06-01

    Recently, it has been demonstrated that martensitic transformation in nanocrystalline shape memory alloys can be suppressed for small grain sizes. Motivated by these results, we study the grain size dependence of martensitic transformations and stress-strain response of nanocrystalline shape memory alloys within the framework of the Ginzburg-Landau (GL) theory. A GL model for a square to rectangle transformation in polycrystals is extended to account for grain boundary effects. We propose that an inhibition of the transformation in grain boundary regions can occur, if the grain boundary energy of the martensite is higher than that of the austenite phase. We show that this inhibition of transformation in grain boundary regions has a strong influence on domain patterns inside grains. Although the transformation is inhibited only at the grain boundaries, it leads to a suppression of the transformation even inside the grains as grain size is decreased. In fact, below a critical grain size, the transformation can be completely suppressed. We explain these results in terms of the extra strain gradient cost associated with grain boundaries, when the transformation is inhibited at grain boundaries. On the other hand, no significant size effects are observed when transformation is not inhibited at grain boundaries. We also study the grain size dependence of the stress strain curve. It is found that when the transformation is inhibited at grain boundaries, a significant reduction in the hysteresis associated with stress-strain curves during the loading-unloading cycles is observed. The hysteresis for this situation reduces even further as the grain size is reduced, which is consistent with recent experiments. The simulations also demonstrate that the mechanical behavior is influenced by inter-granular interactions and the local microstructural neighbourhood of a grain has a stronger influence than the orientation of the grain itself.

  13. Investigation of the size effect for photonic crystals

    Science.gov (United States)

    Liu, M.; Xu, W.; Bai, J.; Chua, C. K.; Wei, J.; Li, Z.; Gao, Y.; Kim, D. H.; Zhou, K.

    2016-10-01

    Three types of photonic crystal (PC) thin films have been prepared for the investigation of their deformation behaviors by nanoindentation tests at the microscale and nanoscale. Each type of PC thin film was composed of poly(methyl methacrylate) (PMMA) nanoparticles with a uniform size. Another type of thin film was prepared by assembling nanoparticles with three different sizes. It was exciting to observe that the hardness and Young’s modulus were significantly improved (more than 15 times) in well-ordered PC thin films than disordered ones. Furthermore, size-dependent mechanical properties were observed for the three types of PCs. Such a size effect phenomenon can be attributed to the special polycrystalline material having a periodical face-centered cubic structure of PC thin films. Furthermore, the indentation size effect that shows that the indentation hardness decreases with an increasing indentation depth has also been observed for all four types of thin films. It is conjectured that the application of the PC structure to other functional materials may enhance their mechanical properties.

  14. 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…

  15. Confidence Intervals for Effect Sizes: Applying Bootstrap Resampling

    Science.gov (United States)

    Banjanovic, Erin S.; Osborne, Jason W.

    2016-01-01

    Confidence intervals for effect sizes (CIES) provide readers with an estimate of the strength of a reported statistic as well as the relative precision of the point estimate. These statistics offer more information and context than null hypothesis statistic testing. Although confidence intervals have been recommended by scholars for many years,…

  16. 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.

  17. Effect of Screen Size on Multimedia Vocabulary Learning

    Science.gov (United States)

    Kim, Daesang; Kim, Dong-Joong

    2012-01-01

    The objective of this study was to investigate the effects of three different screen sizes (small, medium and large) and two types of multimedia instruction (text only and text with pictorial annotation) on vocabulary learning. One hundred thirty-five Korean middle school students learning English as a foreign language were randomly distributed…

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

    NARCIS (Netherlands)

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

    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.

  19. Analytical theory of finite-size effects in mechanical desorption

    NARCIS (Netherlands)

    Skvortsov, A.M.; Klushin, L.I.; Fleer, G.J.; Leermakers, F.A.M.

    2010-01-01

    We discuss a unique system that allows exact analytical investigation of first- and second-order transitions with finite-size effects: mechanical desorption of an ideal lattice polymer chain grafted with one end to a solid substrate with a pulling force applied to the other end. We exploit the analo

  20. Effect Size for Single-Subject Design in Phonological Treatment

    Science.gov (United States)

    Gierut, Judith A.; Morrisette, Michele L.; Dickinson, Stephanie L.

    2015-01-01

    Purpose: The purpose of this study was to document, validate, and corroborate effect size (ES) for single­-subject design in treatment of children with functional phonological disorders; to evaluate potential child-­specific contributing variables relative to ES; and to establish benchmarks for interpretation of ES for the population. Method: Data…

  1. Socialization Effects on the Size of Nigerian Children's Drawings.

    Science.gov (United States)

    Pfeffer, Karen; Olowu, A. A.

    1985-01-01

    Examines the effects of socialization on the size of Yoruba children's drawings of a man and a woman through use of the Draw a Person test. Findings support the prediction that male figures were drawn relatively larger than female figures only in the low income group, reflecting the gender inequality that appears typical of the Yoruba social…

  2. Size-dependent antimicrobial effects of novel palladium nanoparticles.

    Directory of Open Access Journals (Sweden)

    Clara P Adams

    Full Text Available Investigating the interactions between nanoscale materials and microorganisms is crucial to provide a comprehensive, proactive understanding of nanomaterial toxicity and explore the potential for novel applications. It is well known that nanomaterial behavior is governed by the size and composition of the particles, though the effects of small differences in size toward biological cells have not been well investigated. Palladium nanoparticles (Pd NPs have gained significant interest as catalysts for important carbon-carbon and carbon-heteroatom reactions and are increasingly used in the chemical industry, however, few other applications of Pd NPs have been investigated. In the present study, we examined the antimicrobial capacity of Pd NPs, which provides both an indication of their usefulness as target antimicrobial compounds, as well as their potency as potential environmental pollutants. We synthesized Pd NPs of three different well-constrained sizes, 2.0 ± 0.1 nm, 2.5 ± 0.2 nm and 3.1 ± 0.2 nm. We examined the inhibitory effects of the Pd NPs and Pd(2+ ions toward gram negative Escherichia coli (E. coli and gram positive Staphylococcus aureus (S. aureus bacterial cultures throughout a 24 hour period. Inhibitory growth effects of six concentrations of Pd NPs and Pd(2+ ions (2.5 × 10(-4, 10(-5, 10(-6, 10(-7, 10(-8, and 10(-9 M were examined. Our results indicate that Pd NPs are generally much more inhibitory toward S. aureus than toward E. coli, though all sizes are toxic at ≥ 10(-5 M to both organisms. We observed a significant difference in size-dependence of antimicrobial activity, which differed based on the microorganism tested. Our work shows that Pd NPs are highly antimicrobial, and that fine-scale (<1 nm differences in size can alter antimicrobial activity.

  3. Infrared reflectance spectra: Effects of particle size, provenance and preparation

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yin-Fong; Myers, Tanya L.; Brauer, Carolyn S.; Blake, Thomas A.; Forland, Brenda M.; Szecsody, James E.; Johnson, Timothy J.

    2014-09-22

    We have recently developed methods for making more accurate infrared total and diffuse directional - hemispherical reflectance measurements using an integrating sphere. We have found that reflectance spectra of solids, especially powders, are influenced by a number of factors including the sample preparation method, the particle size and morphology, as well as the sample origin. On a quantitative basis we have investigated some of these parameters and the effects they have on reflectance spectra, particularly in the longwave infrared. In the IR the spectral features may be observed as either maxima or minima: In general, upward-going peaks in the reflectance spectrum result from strong surface scattering, i.e. rays that are reflected from the surface without bulk penetration, whereas downward-going peaks are due to either absorption or volume scattering, i.e. rays that have penetrated or refracted into the sample interior and are not reflected. The light signals reflected from solids usually encompass all such effects, but with strong dependencies on particle size and preparation. This paper measures the reflectance spectra in the 1.3 – 16 micron range for various bulk materials that have a combination of strong and weak absorption bands in order to observe the effects on the spectral features: Bulk materials were ground with a mortar and pestle and sieved to separate the samples into various size fractions between 5 and 500 microns. The median particle size is demonstrated to have large effects on the reflectance spectra. For certain minerals we also observe significant spectral change depending on the geologic origin of the sample. All three such effects (particle size, preparation and provenance) result in substantial change in the reflectance spectra for solid materials; successful identification algorithms will require sufficient flexibility to account for these parameters.

  4. Surface and Size Effects in Spin-Crossover Nanocrystals

    Science.gov (United States)

    Gudyma, Iurii; Ivashko, Victor; Bobák, Andrej

    2017-02-01

    We perform Monte Carlo simulations to analyze the surface and size effects in spin-crossover nanocrystals using an Ising-like model including surface and core intermolecular interactions. The consequences of downsizing effect on the transition temperature and the width of hysteresis as finger of the system cooperativity are discussed. The critical temperature is calculated using the real-space renormalization method. The obtained results are in agreement with the experimental data.

  5. Size effects on insect hovering aerodynamics: an integrated computational study

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H [Graduate School of Engineering, Chiba University, Chiba, 263-8522 (Japan); Aono, H [Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI48109 (United States)], E-mail: hliu@faculty.chiba-u.jp, E-mail: aonoh@umich.edu

    2009-03-01

    Hovering is a miracle of insects that is observed for all sizes of flying insects. Sizing effect in insect hovering on flapping-wing aerodynamics is of interest to both the micro-air-vehicle (MAV) community and also of importance to comparative morphologists. In this study, we present an integrated computational study of such size effects on insect hovering aerodynamics, which is performed using a biology-inspired dynamic flight simulator that integrates the modelling of realistic wing-body morphology, the modelling of flapping-wing and body kinematics and an in-house Navier-Stokes solver. Results of four typical insect hovering flights including a hawkmoth, a honeybee, a fruit fly and a thrips, over a wide range of Reynolds numbers from O(10{sup 4}) to O(10{sup 1}) are presented, which demonstrate the feasibility of the present integrated computational methods in quantitatively modelling and evaluating the unsteady aerodynamics in insect flapping flight. Our results based on realistically modelling of insect hovering therefore offer an integrated understanding of the near-field vortex dynamics, the far-field wake and downwash structures, and their correlation with the force production in terms of sizing and Reynolds number as well as wing kinematics. Our results not only give an integrated interpretation on the similarity and discrepancy of the near- and far-field vortex structures in insect hovering but also demonstrate that our methods can be an effective tool in the MAVs design.

  6. A Pre-/Post-Disaster Epidemiological Study of Mental Health Functioning in Vietnam’s Da Nang Province Following Typhoon Xangsane

    Science.gov (United States)

    Acierno, Ron; Amstadter, Ananda B.; Gros, Daniel F.; Richardson, Lisa; Kilpatrick, Dean G.; Trung, Lam Tu; Tuan, Tran; Buoi, La Thi; Ha, Tran Thu; Thach, Tran Duc; Gaboury, Mario T.; Tran, Trinh Luong; Tam, Nguyen Thanh; Seymour, Anne; Galea, Sandro

    2010-01-01

    In 2006, typhoon Xangsane struck Vietnam and disrupted a large-scale mental health needs analysis in the Da Nang province of Vietnam. Recruitment of new participants was halted, and the design of study was altered to that of a pre-/post-event investigation in which 798 of the original 4,982 participants were re-interviewed. This produced the first pre-post disaster epidemiological study. Specifically, risk and protective factors were evaluated with respect to probable mental health “caseness” on the bases of the World Health Organization Short Response Questionnaire (SRQ-20) 7/8 cutoff (i.e., scores of 8 or more). Caseness prevalence was 20.7% pre-disaster and 27.1% post-disaster. Specific risk factors associated with mental health caseness included poor health, extreme peri-disaster fear, and experienced injury. Religious affiliation appeared to be a protective factor. In contrast to US samples, gender was not predictive of outcome. PMID:20523909

  7. 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.

  8. Finite size effects in Neutron Star and Nuclear matter simulations

    CERN Document Server

    Molinelli, P A Giménez

    2014-01-01

    In this work we study molecular dynamics simulations of symmetric nuclear matter using a semi-classical nucleon interaction model. We show that, at sub-saturation densities and low temperatures, the solutions are non-homogeneous structures reminiscent of the ``nuclear pasta'' phases expected in Neutron Star Matter simulations, but shaped by artificial aspects of the simulations. We explore different geometries for the periodic boundary conditions imposed on the simulation cell: cube, hexagonal prism and truncated octahedron. We find that different cells may yield different solutions for the same physical conditions (i.e. density and temperature). The particular shape of the solution at a given density can be predicted analytically by energy minimization. We also show that even if this behavior is due to finite size effects, it does not mean that it vanishes for very large systems and it actually is independent of the system size: The system size sets the only characteristic length scale for the inhomogeneitie...

  9. Grain size effects on He bubbles distribution and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Gao, X.; Gao, N. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Z.G., E-mail: zhgwang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Cui, M.H.; Wei, K.F.; Yao, C.F.; Sun, J.R.; Li, B.S.; Zhu, Y.B.; Pang, L.L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li, Y.F. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Wang, D. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xie, E.Q. [School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China)

    2015-02-15

    Highlights: • SMAT treated T91 and conventional T91 were implanted by 200 keV He{sup 2+} to 1 × 10{sup 21} He m{sup −2} at room temperature and annealed at 450 °C for 3.5 h. • He bubbles in nanometer-size-grained T91 are smaller in as-implanted case. • The bubbles in the matrix of nanograins were hard to detect and those along the nanograin boundaries coalesced and filled with the grain boundaries after annealing. • Brownian motion and coalescence and Ostwald ripening process might lead to bubbles morphology presented in the nanometer-size-grained T91 after annealing. - Abstract: Grain boundary and grain size effects on He bubble distribution and evolution were investigated by He implantation into nanometer-size-grained T91 obtained by Surface Mechanical Attrition Treatment (SMAT) and the conventional coarse-grained T91. It was found that bubbles in the nanometer-size-grained T91 were smaller than those in the conventional coarse-grained T91 in as-implanted case, and bubbles in the matrix of nanograins were undetectable while those at nanograin boundaries (GBs) coalesced and filled in GBs after heat treatment. These results suggested that the grain size of structural material should be larger than the mean free path of bubble’s Brownian motion and/or denuded zone around GBs in order to prevent bubbles accumulation at GBs, and multiple instead of one type of defects should be introduced into structural materials to effectively reduce the susceptibility of materials to He embrittlement and improve the irradiation tolerance of structural materials.

  10. [The effect of group size on salience of member desirability].

    Science.gov (United States)

    Sugimori, S

    1993-04-01

    This study tested the hypothesis that undesirable members are salient in a small group, while desirable members become salient in a larger group. One hundred and forty-five students were randomly assigned to twelve conditions, and read sentences desirably, undesirably, or neutrally describing each member of a college student club. The twelve clubs had one of three group sizes: 13, 39, or 52, and the proportion of the desirable or undesirable to the neutral was either 11:2 or 2:11, forming a three-way (3 x 2 x 2) factorial. Twelve subjects each were asked to make proportion judgments and impression ratings. Results indicated that proportion of the undesirable members was over estimated when the group size was 13, showing negativity bias, whereas proportion of the desirable was overestimated when the size was 52, displaying positivity bias. The size 39 showed neither positivity nor negativity bias. These results along with those from impression ratings suggested that salience of member desirability interacted with group size. It is argued that illusory correlation and group cognition studies may well take these effects into consideration.

  11. Growth of consanguineous populations: effect of family and group size

    Directory of Open Access Journals (Sweden)

    Srdjan Denic

    2012-05-01

    Full Text Available Objective: Although inbreeding is detrimental to the offspring, consanguineous marriages still remain very common in many countries. To better understand this sociobiological puzzle, we compared the growth of isolated consanguineous versus non- consanguineous populations of varying sizes. Methods: In a computer, over five generations, we simulated first cousin marriages, family size, and offspring survival to find the effect on population growth. Results: In large groups, the practice of first cousin marriages decreased the population size due to an excessive number of deaths among the offspring. In small groups, however, first cousin marriages increased the population size; without first cousins, there is a relative shortage of marriageable potential spouses. Marriages to first cousins produced additional unions and a surplus of viable offspring despite excessive deaths caused by inbreeding. Consequently, small consanguineously marrying groups grew faster than small non-consanguineously marrying groups. Independently, family size directly affected the number of consanguineous marriages and inbreeding in consanguineous groups. Conclusions: In small groups, kin marriages, despite the harms of inbreeding, result in relatively faster population growth.

  12. Enhanced oxidation resistance of active nanostructures via dynamic size effect

    Science.gov (United States)

    Liu, Yun; Yang, Fan; Zhang, Yi; Xiao, Jianping; Yu, Liang; Liu, Qingfei; Ning, Yanxiao; Zhou, Zhiwen; Chen, Hao; Huang, Wugen; Liu, Ping; Bao, Xinhe

    2017-01-01

    A major challenge limiting the practical applications of nanomaterials is that the activities of nanostructures (NSs) increase with reduced size, often sacrificing their stability in the chemical environment. Under oxidative conditions, NSs with smaller sizes and higher defect densities are commonly expected to oxidize more easily, since high-concentration defects can facilitate oxidation by enhancing the reactivity with O2 and providing a fast channel for oxygen incorporation. Here, using FeO NSs as an example, we show to the contrary, that reducing the size of active NSs can drastically increase their oxidation resistance. A maximum oxidation resistance is found for FeO NSs with dimensions below 3.2 nm. Rather than being determined by the structure or electronic properties of active sites, the enhanced oxidation resistance originates from the size-dependent structural dynamics of FeO NSs in O2. We find this dynamic size effect to govern the chemical properties of active NSs. PMID:28223687

  13. Policing effectiveness depends on relatedness and group size.

    Science.gov (United States)

    Walter, Bartosz; Brunner, Elisabeth; Heinze, Jürgen

    2011-03-01

    Cohesion of social groups requires the suppression of individual selfishness. Indeed, worker egg laying in insect societies is usually suppressed or punished through aggression and egg removal. The effectiveness of such "policing" is expected to increase with decreasing relatedness, as inclusive fitness of group members is more strongly affected by selfish worker reproduction when group members are less closely related to each other. As inclusive fitness is also influenced by the costs and benefits of helping, the effectiveness of policing should decrease with increasing colony size, because the costs for the whole colony from selfish worker reproduction are proportionally reduced in large groups. Here, we show that policing effectiveness in colonies of the ant Temnothorax unifasciatus is low in large groups and high in small groups when relatedness is high. When we experimentally decreased the relatedness in groups, the policing effectiveness reached the same high level as in small, highly related groups, irrespective of group size. Therefore, our results indicate that policing effectiveness is simultaneously shaped by relatedness and group size, that is, an ecological factor. This may have major implications for testing policing across species of animals.

  14. 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.

  15. 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.

  16. Effect of size on the chaotic behavior of nano resonators

    Science.gov (United States)

    Alemansour, Hamed; Miandoab, Ehsan Maani; Pishkenari, Hossein Nejat

    2017-03-01

    Present study is devoted to investigate the size effect on chaotic behavior of a micro-electro-mechanical resonator under external electrostatic excitation. Using Galerkin's decomposition method, approximating the actuation force with a new effective lumped model, and neglecting higher order terms in the Taylor-series expansion, a simplified model of the main system is developed. By utilizing the Melnikov's method and based on the new form of the electrostatic force, an expression in terms of the system parameters is developed which can be used to rapidly estimate the chaotic region of the simplified system. Based on the analysis of the simple proposed model, it is shown that the effect of size on chaotic region varies significantly depending on bias voltage. By considering the size effect, it is demonstrated that chaotic vibration initiates at much higher constant voltages than predicted by classical theories; and, in high constant voltages, it is shown that strain gradient theory predicts occurrence of chaos at much lower amplitudes.

  17. Sample size for cluster randomized trials: effect of coefficient of variation of cluster size and analysis method.

    Science.gov (United States)

    Eldridge, Sandra M; Ashby, Deborah; Kerry, Sally

    2006-10-01

    Cluster randomized trials are increasingly popular. In many of these trials, cluster sizes are unequal. This can affect trial power, but standard sample size formulae for these trials ignore this. Previous studies addressing this issue have mostly focused on continuous outcomes or methods that are sometimes difficult to use in practice. We show how a simple formula can be used to judge the possible effect of unequal cluster sizes for various types of analyses and both continuous and binary outcomes. We explore the practical estimation of the coefficient of variation of cluster size required in this formula and demonstrate the formula's performance for a hypothetical but typical trial randomizing UK general practices. The simple formula provides a good estimate of sample size requirements for trials analysed using cluster-level analyses weighting by cluster size and a conservative estimate for other types of analyses. For trials randomizing UK general practices the coefficient of variation of cluster size depends on variation in practice list size, variation in incidence or prevalence of the medical condition under examination, and practice and patient recruitment strategies, and for many trials is expected to be approximately 0.65. Individual-level analyses can be noticeably more efficient than some cluster-level analyses in this context. When the coefficient of variation is <0.23, the effect of adjustment for variable cluster size on sample size is negligible. Most trials randomizing UK general practices and many other cluster randomized trials should account for variable cluster size in their sample size calculations.

  18. Power and sample size in cost-effectiveness analysis.

    Science.gov (United States)

    Laska, E M; Meisner, M; Siegel, C

    1999-01-01

    For resource allocation under a constrained budget, optimal decision rules for mutually exclusive programs require that the treatment with the highest incremental cost-effectiveness ratio (ICER) below a willingness-to-pay (WTP) criterion be funded. This is equivalent to determining the treatment with the smallest net health cost. The designer of a cost-effectiveness study needs to select a sample size so that the power to reject the null hypothesis, the equality of the net health costs of two treatments, is high. A recently published formula derived under normal distribution theory overstates sample-size requirements. Using net health costs, the authors present simple methods for power analysis based on conventional normal and on nonparametric statistical theory.

  19. Size effects in Al nanopillars: Single crystalline vs. bicrystalline

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, Allison; Pathak, Siddhartha [Division of Engineering and Applied Sciences, California Institute of Technology, 1200 East California Boulevard, MC 309-81, Pasadena, CA 91125-8100 (United States); Greer, Julia R., E-mail: jrgreer@caltech.edu [Division of Engineering and Applied Sciences, California Institute of Technology, 1200 East California Boulevard, MC 309-81, Pasadena, CA 91125-8100 (United States)

    2011-06-15

    The mechanical behavior of bicrystalline aluminum nano-pillars under uniaxial compression reveals size effects, a stochastic stress-strain signature, and strain hardening. Pillar diameters range from 400 nm to 2 {mu}m and contain a single, non-sigma high angle grain boundary oriented parallel to the pillar axes. Our results indicate that these bicrystalline pillars are characterized by intermittent strain bursts and exhibit an identical size effect to their single crystalline counterparts. Further, we find that the presence of this particular grain boundary generally decreases the degree of work hardening relative to the single crystalline samples. These findings, along with transmission electron microscopy analysis, show that nano-pillar plasticity in the presence of a grain boundary is also characterized by dislocation avalanches, likely resulting from dislocation nucleation-controlled mechanisms, and that at these small length scales this grain boundary may serve as a dislocation sink rather than a dislocation source.

  20. Shear-banding Induced Indentation Size Effect in Metallic Glasses

    Science.gov (United States)

    Lu, Y. M.; Sun, B. A.; Zhao, L. Z.; Wang, W. H.; Pan, M. X.; Liu, C. T.; Yang, Y.

    2016-06-01

    Shear-banding is commonly regarded as the “plasticity carrier” of metallic glasses (MGs), which usually causes severe strain localization and catastrophic failure if unhindered. However, through the use of the high-throughput dynamic nanoindentation technique, here we reveal that nano-scale shear-banding in different MGs evolves from a “distributed” fashion to a “localized” mode when the resultant plastic flow extends over a critical length scale. Consequently, a pronounced indentation size effect arises from the distributed shear-banding but vanishes when shear-banding becomes localized. Based on the critical length scales obtained for a variety of MGs, we unveil an intrinsic interplay between elasticity and fragility that governs the nanoscale plasticity transition in MGs. Our current findings provide a quantitative insight into the indentation size effect and transition mechanisms of nano-scale plasticity in MGs.

  1. 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

  2. Size Effect of Electromagnetic Constitutive Characteristics of Ultrathin Al Films

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The ultrathin aluminum films with thickness in the range of 2~60 nm have been deposited by dc magnetron sputtering apparatus. Reflectance and transmittance of the obtained samples were measured with a WFZ-900-D4 UV/VIS spectrophotometer. The optical constant (n, k) and permittivity (ε', e") were determined by applying Newton-Simpson recurrent substitution method. The results indicate that the electromagnetic constitutive characteristic of ultrathin aluminum films is a function of thickness and has obvious size effect.

  3. Response to recurrent selection under small effective population size

    Directory of Open Access Journals (Sweden)

    Souza Jr. Cláudio Lopes de

    2000-01-01

    Full Text Available A formula was derived for the prediction of the response to recurrent selection when the effective population size (Ne is small. Usually, responses to selection have been estimated by Rs = icsigma²A/sigmaPh, where i, c, sigma²A, and sigmaPh stand for standardized selection differential, parental control, additive variance, and phenotypic standard deviation, respectively. This expression, however, was derived under the assumption of infinite population size. By introducing the effects of finite population size, the expression derived was Rs = [ic(sigma²A + deltaFD1/sigmaPh] - DFID, where deltaF, ID and D1 are the changes in the inbreeding coefficient, the inbreeding depression, and the covariance of additive and homozygous dominance effects, respectively. Thus, the predicted responses to selection based on these expressions will be smaller than those based on the standard procedures for traits with a high level of dominance such as yield. Responses to five cycles of half-sib selection were predicted for maize by both expressions, considering that 100 progenies were evaluated and 10 S1 progenies were recombined, which corresponds to Ne = 10 for each cycle. The accumulated response to selection estimated with the new expression was about 47 and 28% smaller than that based on the standard expression for yield and plant height, respectively. Thus, the expression usually used overestimates the responses to selection, which is in agreement with reported results, because it does not take into account the effective population size that is generally small in recurrent selection programs

  4. Transverse Beam Size Effects on Longitudinal Profile Reconstruction

    CERN Document Server

    Andonian, G; Murokh, A; Dunning, M; Marcus, G; Rosenzweig, J; Williams, O; Yakimenko, V

    2010-01-01

    The use of coherent transition radiation autocorrelation methods to determine bunch length and profile information is examined with the compressed electron beam at the BNL ATF. A bi-gaussian fit is applied to coherent transition radiation auto-correlation data to extract the longitudinal current distribution. The effects of large transverse beam sizes are studied in theory and compared to experimental results. A suitable form of the correction factor is derived for beams with large transverse-longitudinal aspect ratios.

  5. Implicit Finite-Size Effects in Computer Simulations

    OpenAIRE

    Denton, A. R.; EGELSTAFF, P. A.

    1997-01-01

    The influence of periodic boundary conditions (implicit finite-size effects) on the anisotropy of pair correlations in computer simulations is studied for a dense classical fluid of pair-wise interacting krypton atoms near the triple point. Molecular dynamics simulation data for the pair distribution function of N-particle systems, as a function of radial distance, polar angle, and azimuthal angle are compared directly with corresponding theoretical predictions [L. R. Pratt and S. W. Haan, J....

  6. Size Effects in Impact Damage of Composite Sandwich Panels

    Science.gov (United States)

    Dobyns, Alan; Jackson, Wade

    2003-01-01

    Panel size has a large effect on the impact response and resultant damage level of honeycomb sandwich panels. It has been observed during impact testing that panels of the same design but different panel sizes will show large differences in damage when impacted with the same impact energy. To study this effect, a test program was conducted with instrumented impact testing of three different sizes of sandwich panels to obtain data on panel response and residual damage. In concert with the test program. a closed form analysis method was developed that incorporates the effects of damage on the impact response. This analysis method will predict both the impact response and the residual damage of a simply-supported sandwich panel impacted at any position on the panel. The damage is incorporated by the use of an experimental load-indentation curve obtained for the face-sheet/honeycomb and indentor combination under study. This curve inherently includes the damage response and can be obtained quasi-statically from a rigidly-backed specimen or a specimen with any support conditions. Good correlation has been obtained between the test data and the analysis results for the maximum force and residual indentation. The predictions can be improved by using a dynamic indentation curve. Analyses have also been done using the MSC/DYTRAN finite element code.

  7. Effect of sonication on the particle size of montmorillonite clays.

    Science.gov (United States)

    Poli, Alessandra L; Batista, Tatiana; Schmitt, Carla C; Gessner, Fergus; Neumann, Miguel G

    2008-09-15

    This paper reports on the effect of sonication on SAz-1 and SWy-1 montmorillonite suspensions. Changes in the size of the particles of these materials and modifications of their properties have been investigated. The variation of the particle size has been analyzed by DLS (dynamic light scattering). In all cases the clay particles show a bimodal distribution. Sonication resulted in a decrease of the larger modal diameter, as well as a reduction of its volume percentage. Simultaneously, the proportion of the smallest particles increases. After 60 min of sonication, SAz-1 presented a very broad particle size distribution with a modal diameter of 283 nm. On the other hand, the SWy-1 sonicated for 60 min presents a bimodal distribution of particles at 140 and 454 nm. Changes in the properties of the clay suspensions due to sonication were evaluated spectroscopically from dye-clay interactions, using Methylene Blue. The acidic sites present in the interlamellar region, which are responsible for dye protonation, disappeared after sonication of the clay. The changes in the size of the scattering particles and the lack of acidic sites after sonication suggest that sonication induces delamination of the clay particles.

  8. Serving size guidance for consumers: is it effective?

    Science.gov (United States)

    Faulkner, G P; Pourshahidi, L K; Wallace, J M W; Kerr, M A; McCrorie, T A; Livingstone, M B E

    2012-11-01

    Larger portion sizes (PS) may be inciting over-eating and contributing to obesity rates. Currently, there is a paucity of data on the effectiveness of serving size (SS) guidance. The aims of the present review are to evaluate SS guidance; the understanding, usability and acceptability of such guidance, its impact on consumers and potential barriers to its uptake. A sample of worldwide SS guidance schemes (n 87) were identified using targeted and untargeted searches, overall these were found to communicate various inconsistent and often conflicting messages about PS selection. The available data suggest that consumers have difficulty in understanding terms such as 'portion size' and 'serving size', as these tend to be used interchangeably. In addition, discrepancies between recommended SS and those present on food labels add to the confusion. Consumers generally understand and visualise SS best when expressed in terms of household measures rather than actual weights. Only a limited number of studies have examined the direct impact of SS guidance on consumer behaviour with equivocal results. Although consumers recognise that guidance on selecting SS would be helpful, they are often unwilling to act on such guidance. The challenge of achieving consumer adherence to SS guidance is formidable due to several barriers including chronic exposure to larger PS, distorted consumption norms and perceptions, the habit of 'cleaning one's plate' and language barriers for ethnic minorities. In conclusion, the impact of SS guidance on consumers merits further investigation to ensure that future guidance resonates with consumers by being more understandable, usable and acceptable.

  9. Effect of MTA particle size on periapical healing.

    Science.gov (United States)

    Torabinejad, M; Moazami, M; Moaddel, H; Hawkins, J; Gustefson, C; Faras, H; Wright, K; Shabahang, S

    2016-12-15

    To examine the effect of reduction in MTA particle size on dento-alveolar and osseous healing in dogs. Root canals of 24 mandibular premolars in four 2-year-old beagles were prepared and filled with gutta-percha and sealer. Two to four weeks later, during periapical surgery, the root-end cavity preparations in these teeth were filled with either grey ProRoot MTA or modified (reduced particle sizes with faster setting time) MTA. The animals were sacrificed 4 months later. Degrees of inflammation, type of inflammatory cells, fibrous connective tissue adjacent to the root-end filling materials, cementum formation over the resected roots and root-end filling materials and bone healing were examined. Data were analysed using the McNemar test. No significant differences in healing of periapical tissues were found when comparing ProRoot MTA to a modified MTA containing reduced particle sizes. Reducing the particle sizes of MTA did not impact its biological properties. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  10. PECVD Environmental Effects on Silicon Nanoparticle Size and Quality

    Science.gov (United States)

    Klafehn, Grant; Kendrick, Chito; Guan, Tianyuan; Theingi, San; Riskey, Kory; Vitti, Lauren; Bagolini, Luigi; Lusk, Mark; Gorman, Brian; Taylor, Craig; Collins, Reuben; Fields, Jeremy; Stradins, Paul

    2014-03-01

    Silicon based nanoparticles (SiNPs) have recently been of great interest to the PV community because of their unique properties compared to their bulk constituents. By decreasing a nanoparticle's (NP) size below its exciton Bohr radius, its band gap can be increased relative to the bulk. This talk will discuss fundamental variables involved in defining and controlling plasma-grown SiNP size and quality. A quartz tube with a RF electrode ring is used to create a plasma in an argon-silane mixture to grow the SiNPs. Their quality and size can be changed by varying the reactor pressure, gas flow, and thus the resulting residence time. They are then characterized by Raman, PL, ESR, XRD, and TEM, and then mapped to a phase diagram with respect to pressure and flow. Higher residence times of 10 ms resulted in highly crystalline, 7 nm SiNPs. Residence times of 2 ms create 4 nm particles, while below 2 ms will result in highly defective material, even though the PL exhibits peaks at 1.6 eV. These parameters will be discussed, including how each variable affects the resultant SiNP size, quality. Also included will be a discussion about additive gasses and their additional effects on SiNP characteristics. We acknowledge support given by the DOE (DE-EE0005326) and NSF REMRSEC (DMR 0820518).

  11. On the size effect in PAFC grid-connected plant

    Energy Technology Data Exchange (ETDEWEB)

    Bizzarri, Giacomo [Dipartimento di Architettura, Universita di Ferrara, Via Quartieri 8, 44100 Ferrara (Italy)

    2006-07-15

    This article is the final part of a research project aimed at exploring the potential of energy retrofit through fuel cell hybrid plants. If previous papers revealed the considerable environmental benefits in terms of primary energy saving and pollutant emission reduction that could be achieved by such a shift, they also demonstrated that these plants are feasible only when appropriate financial incentives are given. The identification of the best PAFC plant size thus represents a key target resulting in significant economic savings. Therefore, in this paper, several hybrid scenarios are investigated, taking nine hospitals of Ferrara province (Italy) as the study sample. Investigations reveal that the more the proper sizing is carried out in search of the highest environmental and energy benefits, the higher the financial returns will be. The knowledge of this size effect could be adopted as a useful design guideline and can be taken as a first criterion for the adoption of these systems. A first methodology for the proper sizing of fuel cell plants is suggested. (author)

  12. Size and shape effects on magnetic properties of Ni nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Xuemin He; Huigang Shi

    2012-01-01

    Pure Ni nanoparticles ranging in size from 24 to 200nm are prepared via thermal decomposition of nickel acetylacetonate in oleylamine.The as-prepared Ni particles change from spherical to dendritic or starlike with increasing precursor concentration.The particles are stable because the organic coating occurs in situ.Magnetic measurement reveals that all the Ni nanoparticles are ferromagnetic and show ferromagnetic-paramagnetic transitions at their Curie points.The saturation magnetization Ms is sizedependent,with a maximum value of 52.01 and 82.31 emu/g at room temperature and 5 K,respectively.The coercivity decreases at first and then increases with increasing particle size,which is attributed to the competition between size effect and shape anisotropy.The Curie temperature Tc is 593,612,622,626 and 627 K for the 24,50,96,165 and 200 nm Ni nanoparticles,respectively.A theoretical model is proposed to explain the size-dependence of Ni nanoparticle Curie temperature.

  13. Overestimation of the effect size in group sequential trials.

    Science.gov (United States)

    Zhang, Jenny J; Blumenthal, Gideon M; He, Kun; Tang, Shenghui; Cortazar, Patricia; Sridhara, Rajeshwari

    2012-09-15

    Group sequential designs (GSD), which provide for interim monitoring of efficacy data and allow potential early trial termination while preserving the type I error rate, have become commonplace in oncology clinical trials. Although ethically appealing, GSDs tend to overestimate the true treatment effect size at early interim analyses. Overestimation of the treatment effect may exaggerate the benefit of a drug and provide imprecise information for physicians and their patients about a drug's true effect. The cause and effect of such a phenomenon are generally not well understood by many in clinical trial practice. In this article, we provide a graphical explanation for why the phenomenon of overestimation in GSDs occurs. The potential overestimation of the magnitude of the treatment effect is of particular concern in oncology, in which the more subjective endpoint of progression-free survival has increasingly been adopted as the primary endpoint in pivotal phase III trials. ©2012 AACR.

  14. Reinforced polypropylene composites: effects of chemical compositions and particle size.

    Science.gov (United States)

    Ashori, Alireza; Nourbakhsh, Amir

    2010-04-01

    In this work, the effects of wood species, particle sizes and hot-water treatment on some physical and mechanical properties of wood-plastic composites were studied. Composites of thermoplastic reinforced with oak (Quercus castaneifolia) and pine (Pinus eldarica) wood were prepared. Polypropylene (PP) and maleic anhydride grafted polypropylene (MAPP) were used as the polymer matrix and coupling agent, respectively. The results showed that pine fiber had significant effect on the mechanical properties considered in this study. This effect is explained by the higher fiber length and aspect ratio of pine compared to the oak fiber. The hot-water treated (extractive-free) samples, in both wood species, improved the tensile, flexural and impact properties, but increased the water absorption for 24h. This work clearly showed that lignocellulosic materials in both forms of fiber and flour could be effectively used as reinforcing elements in PP matrix. Furthermore, extractives have marked effects on the mechanical and physical properties.

  15. Hofmeister effects: interplay of hydration, nonelectrostatic potentials, and ion size.

    Science.gov (United States)

    Parsons, Drew F; Boström, Mathias; Lo Nostro, Pierandrea; Ninham, Barry W

    2011-07-21

    The classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloids, and corresponding theories of electrolytes, are unable to explain ion specific forces between colloidal particles quantitatively. The same is true generally, for surfactant aggregates, lipids, proteins, for zeta and membrane potentials and in adsorption phenomena. Even with fitting parameters the theory is not predictive. The classical theories of interactions begin with continuum solvent electrostatic (double layer) forces. Extensions to include surface hydration are taken care of with concepts like inner and outer Helmholtz planes, and "dressed" ion sizes. The opposing quantum mechanical attractive forces (variously termed van der Waals, Hamaker, Lifshitz, dispersion, nonelectrostatic forces) are treated separately from electrostatic forces. The ansatz that separates electrostatic and quantum forces can be shown to be thermodynamically inconsistent. Hofmeister or specific ion effects usually show up above ≈10(-2) molar salt. Parameters to accommodate these in terms of hydration and ion size had to be invoked, specific to each case. Ionic dispersion forces, between ions and solvent, for ion-ion and ion-surface interactions are not explicit in classical theories that use "effective" potentials. It can be shown that the missing ionic quantum fluctuation forces have a large role to play in specific ion effects, and in hydration. In a consistent predictive theory they have to be included at the same level as the nonlinear electrostatic forces that form the skeletal framework of standard theory. This poses a challenge. The challenges go further than academic theory and have implications for the interpretation and meaning of concepts like pH, buffers and membrane potentials, and for their experimental interpretation. In this article we overview recent quantitative developments in our evolving understanding of the theoretical origins of specific ion, or Hofmeister effects. These are demonstrated

  16. Effect of Size Polydispersity on Melting of Charged Colloidal Systems

    Institute of Scientific and Technical Information of China (English)

    陈勇

    2003-01-01

    We introduce simple prescriptions of the Yukawa potential to describe the effect of size polydispersity and macroion shielding effect in charged colloidal systems. The solid-liquid phase boundaries were presented with the Lindemann criterion based on molecular dynamics simulations. Compared with the Robbins-Kremer-Grest simulation results, a deviation of melting line is observed at small λ, which means large macroion screening length. This deviation of phase boundary is qualitatively consistent with the simulation result of the nonlinear Poisson-Boltzmann equation with full many-body interactions. It is found that this deviation of the solid-liquid phase behaviour is sensitive to the screening parameter.

  17. Visual acuity in mammals: effects of eye size and ecology.

    Science.gov (United States)

    Veilleux, Carrie C; Kirk, E Christopher

    2014-01-01

    Previous comparative research has attributed interspecific variation in eye size among mammals to selection related to visual acuity. Mammalian species have also been hypothesized to differ in visual acuity partly as a result of differences in ecology. While a number of prior studies have explored ecological and phylogenetic effects on eye shape, a broad comparative analysis of the relationships between visual acuity, eye size and ecology in mammals is currently lacking. Here we use phylogenetic comparative methods to explore these relationships in a taxonomically and ecologically diverse sample of 91 mammal species. These data confirm that axial eye length and visual acuity are significantly positively correlated in mammals. This relationship conforms to expectations based on theoretical optics and prior analyses of smaller comparative samples. Our data also demonstrate that higher visual acuity in mammals is associated with: (1) diurnality and (2) predatory habits once the effects of eye size and phylogeny have been statistically controlled. These results suggest that interspecific variation in mammalian visual acuity is the result of a complex interplay between phylogenetic history, visual anatomy and ecology.

  18. 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.

  19. Ion size effect on colloidal forces within the primitive model

    Directory of Open Access Journals (Sweden)

    J.Wu

    2005-01-01

    Full Text Available The effect of ion size on the mean force between a pair of isolated charged particles in an electrolyte solution is investigated using Monte Carlo simulations within the framework of the primitive model where both colloidal particles and small ions are represented by charged hard spheres and the solvent is treated as a dielectric continuum. It is found that the short-ranged attraction between like-charged macroions diminishes as the diameter of the intermediating divalent counterions and coions increases and the maximum attractive force is approximately a linear function of the counterion diameter. This size effect contradicts the prediction of the Asakura-Oosawa theory suggesting that an increase in the excluded volume of small ions would lead to a stronger depletion between colloidal particles. Interestingly, the simulation results indicate that both the hard-sphere collision and the electrostatic contributions to the mean force are insensitive to the size disparity of colloidal particles with the same average diameter.

  20. 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.

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

    CERN Document Server

    Treviño, Santiago; Del Genio, Charo I; Bassler, Kevin E

    2014-01-01

    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 Erd\\H{o}s-R\\'enyi 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.

  2. Shaking and Blending Effect on Microalgae Concentrates Size

    Directory of Open Access Journals (Sweden)

    LUDI PARWADANI AJI

    2012-03-01

    Full Text Available Microalgae concentrates (paste can be used as an alternative feed to replace live microalgae for aquaculture due to its nutritional value and convenience. However, the clumping of cells and negative buoyancy of algae concentrate can affect bivalve culture as bivalves only capture particles in suspension and ingest a certain size range of particles. This study investigated the effect of shaking and blending treatments on the preparation of food suspensions prepared from algae concentrates (Isochrysis and Pavlova. The results indicated that the higher the shaking time (5, 10, and 15 times or blending time (10, 30, and 60 seconds, the smaller was the diameter of the resulting algae particles. Moreover, the greater the volume of algae concentrate used in preparation, the larger the diameter of algae particles produced. Shaking may be the best option because it is cheaper and simpler. However, all the treatments provided a suitable particle size range for ingestion by bivalves.

  3. Climate Change Effects on Shallow Landslide Location, Size, and Frequency

    Science.gov (United States)

    Bellugi, D.; McKean, J. A.; Rulli, M.; Dietrich, W. E.

    2011-12-01

    Shallow landslides which typically involve just the soil mantle are influenced by root strength, storm-induced shallow pore pressures, and soil thickness. Field mapping indicates that landslides commonly occur in steep and topographically convergent areas along the soil-bedrock boundary. The susceptibility of a landscape to shallow landslides is controlled by topography and vegetation, while landslide triggering events are mostly related to hydrologic factors such as rainfall total and storm intensity and duration. Climate change can potentially affect both landslide susceptibility and triggering through changes in the hydro-meteorological variables as well as through feedbacks among climate, hydrology and vegetation. Vegetation (and forests in particular) plays an important role through the stabilizing effect of root systems and through its dynamic role on the hydrological cycle. Vegetation type and survival is directly related to climate through temperature and precipitation, and vegetation type could change significantly as some species may not survive while others could be displaced to more favorable locations in response to climate change. In addition, changes in soil moisture can negatively affect forest health by promoting forest disease, insect infestations and fires, and causing significant changes in forest composition. The conversion of forest vegetation to weaker-rooted or sparsely distributed vegetation as well as other disturbances to the forest ecosystem can enhance landslide susceptibility. Assessing the impact of climate change on shallow landsliding is challenging because we are currently unable to predict the size and location of landslides. Under the assumption that landslide location and size are controlled by the spatial structure of pore pressure development, soil depth, and vegetation across the landscape, we adopt a novel search procedure based on graph partitioning techniques to reformulate classical "factor of safety" analysis of a

  4. Effects of particle size on the leachability of trace elements

    Energy Technology Data Exchange (ETDEWEB)

    M. Zandi; N.V. Russell; R.G.J. Edyvean; R. Hand; P. Ward [University of Sheffield, Sheffield (United Kingdom). Department of Chemical and Process Engineering

    2007-07-01

    Leaching tests are widely used as indicators to estimate the release potential of hazardous elements from solid materials under laboratory conditions in order to assess environmental impacts of utilisation or deposition of the examined material. Several institutes and agencies have introduced standard leaching tests for estimating the mobility of trace elements from a solid material under specific conditions. These tests are often criticised on the grounds that the results obtained are neither reliable nor able to be extrapolated to the application. The lack of agreement between the estimates by standard leaching tests and measurements in the field may be the result of inadequate specification of the physical and chemical conditions used in the test. For example, in BS EN 12457 the particle size distribution of the sample is not well defined. This can lead to different interpretations by different laboratories resulting in different leaching rates being reported. The lack of understanding of the leaching mechanism leads to the design of poorly defined leaching tests. Therefore, there is a need to have a good understanding of all parameters involved in the leaching process and the factors that affect it. It is known that particle surface area has a great impact on the leachability of trace elements from solid matter. This paper investigates effects of particle size on the leaching process using BS EN 12457-2 conditions. A slag sample from a metal refiner has been crushed and sieved to obtain different fractions with different particle sizes from 4 to 0.5 mm. The leaching rate of trace elements from each fraction has been determined using deionised water as the leachant. It was found that sample preparation procedure is a critical step in leaching analysis and effects of particle size on the leachability should be taken into account. 9 refs., 2 figs., 2 tabs.

  5. Sample-Size Planning for More Accurate Statistical Power: A Method Adjusting Sample Effect Sizes for Publication Bias and Uncertainty.

    Science.gov (United States)

    Anderson, Samantha F; Kelley, Ken; Maxwell, Scott E

    2017-09-01

    The sample size necessary to obtain a desired level of statistical power depends in part on the population value of the effect size, which is, by definition, unknown. A common approach to sample-size planning uses the sample effect size from a prior study as an estimate of the population value of the effect to be detected in the future study. Although this strategy is intuitively appealing, effect-size estimates, taken at face value, are typically not accurate estimates of the population effect size because of publication bias and uncertainty. We show that the use of this approach often results in underpowered studies, sometimes to an alarming degree. We present an alternative approach that adjusts sample effect sizes for bias and uncertainty, and we demonstrate its effectiveness for several experimental designs. Furthermore, we discuss an open-source R package, BUCSS, and user-friendly Web applications that we have made available to researchers so that they can easily implement our suggested methods.

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    Gang Bai

    2015-09-01

    Full Text Available 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.

  8. 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.

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

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2015-01-01

    Rolling processes for which the characteristic length scale reaches into the range where size effects become important are receiving increased interest. In particularly, this is owed to the roll-molding process under development for high-throughput of micron-scale surface features. The study...... 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...... 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...

  10. 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.

  11. Finite-size effects in amorphous indium oxide

    Science.gov (United States)

    Mitra, Sreemanta; Tewari, Girish C.; Mahalu, Diana; Shahar, Dan

    2016-04-01

    We study the low-temperature magnetotransport properties of several highly disordered amorphous indium oxide (a:InO) samples. Simultaneously fabricated devices comprising a two-dimensional (2D) film and 10 -μ m -long wires of different widths were measured to investigate the effect of size as we approach the 1D limit, which is around 4 times the correlation length, and happens to be around 100 nm for a:InO. The film and the wires showed magnetic field (B )-induced superconductor to insulator transition (SIT). In the superconducting side, the resistance increased with decrease in wire width, whereas an opposite trend is observed in the insulating side. We find that this effect can be explained in light of charge-vortex duality picture of the SIT. Resistance of the 2D film follows an activated behavior over the temperature (T ), whereas, the wires show a crossover from the high-T -activated to a T -independent behavior. At high-temperature regime the wires' resistance follow the film's until they deviate and became independent of T . We find that the temperature at which this deviation occurs evolves with the magnetic field and the width of the wire, which show the effect of finite size on the transport.

  12. Effect of filler size on wear resistance of resin cement.

    Science.gov (United States)

    Shinkai, K; Suzuki, S; Katoh, Y

    2001-11-01

    The purpose of this study was to evaluate the effect of filler size on the wear of resin cements. Materials tested included four experimental dual-cure resin cements (Kuraray) consisting of different-sized filler particles. A rectangular box cavity was prepared on the flattened occlusal surface of extracted human molars. Ceramic inlays for the cavities were fabricated using the Cerec 2 system. The Cerec inlays were cemented with the respective cements and adhesive systems according to the manufacturer's directions. The restored surface was finished by wet-grinding with an 800-grit silicon carbide paper. Six specimens were prepared for each resin cement. Half of the specimens were subjected to a three-body wear test for 200,000 cycles, and the others were subjected to a toothbrush abrasion test for 30,000 cycles. The worn surface of each restoration was scanned by a profilometer (Surfcom 475 A) at eight different points for each restoration. The wear value was determined by measuring the vertical gap depth on the profilometric tracings. The data were statistically analyzed by one-way analysis of variance (ANOVA) and Scheffe's test. The results showed that, with increase of filler size, the wear value decreased in the toothbrush test and increased in the three-body wear test. The cement with 0.04-microm filler exhibited the lowest wear value among the materials in the three-body wear test, and the same wear value as the cement with 0.97-microm filler in the toothbrush test. Based upon the results of this study, it is concluded that the wear of resin cements was affected by the filler size as well as the mode of wear test.

  13. 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

  14. Size Effect Of Glulam Beams In Tension Perpendicular To Grain

    DEFF Research Database (Denmark)

    Astrup, Thomas; Odin Clorius, Christian; 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...

  15. Size-dispersity effects in two-dimensional melting.

    Science.gov (United States)

    Watanabe, Hiroshi; Yukawa, Satoshi; Ito, Nobuyasu

    2005-01-01

    In order to investigate the effect of size dispersity on two-dimensional melting transitions, hard-disk systems with equimolar bidispersity are studied by means of particle dynamics simulations. From the nonequilibrium relaxation behaviors of bond-orientational order parameters, we find that (i) there is a critical dispersity at which the melting transition of the hexagonal solid vanishes and (ii) the quadratic structure is metastable in a certain region of the dispersity-density parameter space. These results suggest that the dispersity not only destroys order but produces new structures under certain specific conditions.

  16. Size-effects in plane strain sheet-necking

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Redanz, Pia

    2003-01-01

    are analyzed. The strain gradient plasticity theory predicts delayed onset of localization when compared to conventional theory, and it depresses deformation localization in the neck. The sensitivity to imperfections is analyzed as well as differently hardening materials.......A finite strain generalization of the strain gradient plasticity theory by Fleck and Hutchinson (2001) is proposed and used to study size effects in plane strain necking of thin sheets using the finite element method. Both sheets with rigid grips at the ends and specimens with shear free ends...

  17. Size-effects in plane strain sheet-necking

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Redanz, Pia

    2004-01-01

    and specimens with shear free ends are analyzed. The strain gradient plasticity theory predicts delayed onset of localization when compared to conventional theory, and it depresses deformation localization in the neck. The sensitivity to imperfections is analyzed as well as differently hardening materials. (C......A finite strain generalization of the strain gradient plasticity theory by Fleck and Hutchinson (J. Mech. Phys. Solids 49 (2001a) 2245) is proposed and used to study size effects in plane strain necking of thin sheets using the finite element method. Both sheets with rigid grips at the ends...

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    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......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...

  19. 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 ...

  20. Effect of body size on toxicity of zinc in neonates of four differently sized Daphnia species

    NARCIS (Netherlands)

    Vesela, S.; Vijverberg, J.

    2007-01-01

    The sensitivity of neonates of four Daphnia species to zinc was tested in relation to their mean body size. These mean sizes of these four Daphnia spp were: D. magna, 0.813 ± 0.055 mm, D.␣pulicaria, 0.745 ± 0.063 mm, D. pulex, 0.645 ± 0.044 mm and D. galeata, 0.611 ± 0.058 mm. A positive relationshi

  1. Effects of Kurozu concentrated liquid on adipocyte size in rats

    Directory of Open Access Journals (Sweden)

    Nakamura Kumi

    2010-11-01

    Full Text Available Abstract Background Kurozu concentrated liquid (KCL is used as a health-promoting supplement for the treatment of disorders such as cancer, hyperlipidemia, and hypertension in Japan. We investigated the possible anti-obesity effects of KCL in rats. Methods Male Sprague Dawley rats were fed American Institute of Nutrition 76 formula diet and were orally administrated KCL or acetic acid at a dose of 100 mg/kg body weight or deionized water for 4 weeks. Adipocyte size, DNA content in subcutaneous adipose tissue, lipid levels in the serum and liver, and the rate of fatty acid excretion were determined. Effects of KCL on pancreatic lipase activity and 3T3-L1 preadipocyte differentiation were investigated in vitro. Results In the KCL group, the average adipocyte size in subcutaneous and perirenal adipose tissues was significantly reduced. The KCL-administered rats displayed greater numbers of small adipocytes in the subcutaneous, perirenal and mesenteric adipose tissues than did rats from the other groups. In the KCL group, the DNA content in subcutaneous adipose tissue was significantly increased. The rate of fatty acid excretion was significantly increased in the KCL group. Furthermore, KCL significantly inhibited pancreatic lipase activity in vitro, and also significantly inhibited fat accumulation and mRNA expression of fatty acid binding protein 2 (aP2 and peroxisome proliferator-activated γ (PPARγ in 3T3-L1 preadipocyte. The levels of serum and liver lipids, the concentration of serum glucose, and the levels of adiponectin were similar among the 3 groups. Conclusion Oral administration of KCL decreases the adipocyte size via inhibition of dietary fat absorption and reductions of PPARγ and aP2 mRNA expression levels in adipocytes.

  2. Effects of corm size and storage period on allocation

    Directory of Open Access Journals (Sweden)

    mehdi nasiry mahalati

    2009-06-01

    Full Text Available In order to correlate corm size and storage period of corms to allocation of assimilates in different parts of the plant an experiment was conducted during growth period of 2004 and 2005 in Faculty of Agriculture, Ferdowsi University of Mashhad. Treatments were four groups of corm size (3-6, 6-9, 9-12 and 12-15 g either stored for a period of time before planting or sown directly without storage. Experiment was conducted in a Complete Randomized Block design with three replications. Results indicated that storing corms before planting had a negative effect on number, area, length and width of leaf and also on weight of leaf, weight of main shoot, weight of leaves of lateral shoots and total weight of plant. However, weight of corm, number and weight of lateral shoots and area of lateral leaf was not affected by storing the corms. Nevertheless, in the second year, number, length and weight of leaf on main shoot, number of cormlet, number, area and weight of leaf on lateral shoots, total weight of plant, corm weight, weight of main shoot and weight of lateral buds was reduced while leaf width were not affected. Effect of corm size on almost all measured parameters was positive and with increasing corm weight an increasing trend was observed in the above parameters. No flower was observed on corms which were stored, while corms which planted after lifting produced flowers and Larger corms of 9-12 and 12-15 g were superior in terms of number of flowers per unit area and also weight of flower and stigma per unit area. Corms with 9-15 grams planted immediately after lifting the corms produced higher yield.

  3. Size effects in MgO cube dissolution.

    Science.gov (United States)

    Baumann, Stefan O; Schneider, Johannes; Sternig, Andreas; Thomele, Daniel; Stankic, Slavica; Berger, Thomas; Grönbeck, Henrik; Diwald, Oliver

    2015-03-10

    Stability parameters and dissolution behavior of engineered nanomaterials in aqueous systems are critical to assess their functionality and fate under environmental conditions. Using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, we investigated the stability of cubic MgO particles in water. MgO dissolution proceeding via water dissociation at the oxide surface, disintegration of Mg(2+)-O(2-) surface elements, and their subsequent solvation ultimately leads to precipitation of Mg(OH)2 nanosheets. At a pH ≥ 10, MgO nanocubes with a size distribution below 10 nm quantitatively dissolve within few minutes and convert into Mg(OH)2 nanosheets. This effect is different from MgO cubes originating from magnesium combustion in air. With a size distribution in the range 10 nm ≤ d ≤ 1000 nm they dissolve with a significantly smaller dissolution rate in water. On these particles water induced etching generates (110) faces which, above a certain face area, dissolve at a rate equal to that of (100) planes.1 The delayed solubility of microcrystalline MgO is attributed to surface hydroxide induced self-inhibition effects occurring at the (100) and (110) microplanes. The present work underlines the importance of morphology evolution and surface faceting of engineered nanomaterials particles during their dissolution.

  4. Effect Size: A guide for researchers and users

    Directory of Open Access Journals (Sweden)

    Robert Coe

    2003-06-01

    Full Text Available The present article describes a method to quantify the magnitude of the differences between two measures and/or the degree of the effect of a variable about criteria, and it is named likethe effect size measure, d. Use it use in research and applied contexts provides a quitedescriptive complementary information, improving the interpretation of the results obtained bythe traditional methods that emphasize the statistical significance. Severa forms there are of interpreting the d, and an example taken of an experimental research, is presented to clarify the concepts and necessary calculations. This method is not robust to sorne conditions that they candistort its interpretation, for example, the non normality of the data; alternative methods are mentioned to the statistical d. We ending with sorne conclusions that will notice about the appropriate use of it.

  5. 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)

  6. 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)…

  7. 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)…

  8. A preliminary study of material homogeneity for size effect investigations

    Energy Technology Data Exchange (ETDEWEB)

    Krompholz, K.; Kamber, J.; Kalkhof, D.

    1999-06-01

    The forged material 20 MnMoNi 55, material number 1.6310 (heat number 69906) with a heat treatment of 900 {sup o}C, water quenched, 730 {sup o}C, air cooled, was subjected to an intensive quality control consisting of chemical analysis, metallography, hardness tests, tensile tests, and impact tests. Six plates of the material were investigated, and all specimens were taken from a diagonal of each plate in three positions, outer margins and the centre of the plates. The quality control exhibits the following results: (1) The material fulfill the material specification in all respects. (2) This material is a fine grained homogeneous ferritic material of bainitic structure; neither from the chemical analysis, metallography, nor from hardness tests influences from the position of the specimens taken from the plates could be derived. (3) The tensile tests clearly revealed position dependent material properties. With the exception of one plate, one of the selected positions exhibits no natural yield strength, higher rupture strength, and lower elongation to fracture compared with the other two positions at 293 K and 573 K. (4) Many of the data obtained from the impact tests at room temperature were larger than the capacity of the impact machine, i.e. 225 Joule; the experimental condition was changed from tests at 573 K to tests at 253 K to obtain data from the transition region. The main conclusions drawn for the size effect experiments where that all the tensile test results for different specimen sizes have to be discussed with respect of the specimen positions within the plates, and that for all bend bar as well as impact experiments with different specimen sizes the notch depth to specimen width ratio a/w has to be changed from a/w = 0.2 to a/w = 0.3 to get reasonable results within the frame of the available test equipment. (author)

  9. Is Active Design changing the workplace? - A natural pre-post experiment looking at health behaviour and workplace perceptions.

    Science.gov (United States)

    Engelen, Lina; Chau, Josephine; Bohn-Goldbaum, Erika; Young, Sarah; Hespe, Dominique; Bauman, Adrian

    2017-01-01

    Active Design is a relatively new concept and evaluation on its effects on healthy behaviour is lacking. To investigate Active Design influence on workplace physical activity, sedentary behaviour, musculoskeletal complaints, and perceptions of the workplace and productivity. Participants (n = 118 adults) moving from 14 workplaces into a new building completed an online questionnaire pre- and post-move. The questions related to health behaviours (physical activity, sitting time and sleep); musculoskeletal issues; perceptions of the office environment; productivity; and engagement. After the move, 68% of participants were located in an open plan building (21% before the move). In the new workplace participants tended to sit less during their work time (72% - 66%; p health-promoting effects on occupants. Satisfaction with environmental characteristics tended to improve in the new building though perceptions of productivity measures were variable.

  10. Nanometer-Size Effect on Hydrogen Sites in Palladium Lattice.

    Science.gov (United States)

    Akiba, Hiroshi; Kofu, Maiko; Kobayashi, Hirokazu; Kitagawa, Hiroshi; Ikeda, Kazutaka; Otomo, Toshiya; Yamamuro, Osamu

    2016-08-17

    Nanometer-sized materials attract much attention because their physical and chemical properties are substantially different from those of bulk materials owing to their size and surface effects. In this work, neutron powder diffraction experiments on the nanoparticles of palladium hydride, which is the most popular metal hydride, have been performed at 300, 150, and 44 K to investigate the positions of the hydrogen atoms in the face-centered cubic (fcc) lattice of palladium. We used high-quality PdD0.363 nanocrystals with a diameter of 8.0 ± 0.9 nm. The Rietveld analysis revealed that 30% of D atoms are located at the tetrahedral (T) sites and 70% at the octahedral (O) sites. In contrast, only the O sites are occupied in bulk palladium hydride and in most fcc metal hydrides. The temperature dependence of the T-site occupancy suggested that the T-sites are occupied only in a limited part, probably in the subsurface region, of the nanoparticles. This is the first study to determine the hydrogen sites in metal nanoparticles.

  11. Atomic size effects studied by transport in single silicide nanowires

    Science.gov (United States)

    Miccoli, I.; Edler, F.; Pfnür, H.; Appelfeller, S.; Dähne, M.; Holtgrewe, K.; Sanna, S.; Schmidt, W. G.; Tegenkamp, C.

    2016-03-01

    Ultrathin metallic silicide nanowires with extremely high aspect ratios can be easily grown, e.g., by deposition of rare earth elements on semiconducting surfaces. These wires play a pivotal role in fundamental research and open intriguing perspectives for CMOS applications. However, the electronic properties of these one-dimensional systems are extremely sensitive to atomic-sized defects, which easily alter the transport characteristics. In this study, we characterized comprehensively TbSi2 wires grown on Si(100) and correlated details of the atomic structure with their electrical resistivities. Scanning tunneling microscopy (STM) as well as all transport experiments were performed in situ using a four-tip STM system. The measurements are complemented by local spectroscopy and density functional theory revealing that the silicide wires are electronically decoupled from the Si template. On the basis of a quasiclassical transport model, the size effect found for the resistivity is quantitatively explained in terms of bulk and surface transport channels considering details of atomic-scale roughness. Regarding future applications the full wealth of these robust nanostructures will emerge only if wires with truly atomically sharp interfaces can be reliably grown.

  12. 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. PMID:27303317

  13. 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 f

  14. NMR study of size effects in relaxor PMN nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Blinc, Robert [Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Zalar, Bostjan; Zupancic, Blaz [Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); EN-FIST Centre of Excellence, Dunajska cesta 156, 1000 Ljubljana (Slovenia); Morozovska, Anna N. [Institute for Problems of Material Science, National Academy of Sciences of Ukraine, Krjijanovskogo 3, 03142 Kiev (Ukraine); V. Lashkarev Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, prospekt Nauki 41, 03028 Kiev (Ukraine); Glinchuk, Maya D. [Institute for Problems of Material Science, National Academy of Sciences of Ukraine, Krjijanovskogo 3, 03142 Kiev (Ukraine)

    2011-11-15

    {sup 93}Nb 1/2{yields} -1/2 NMR line shape and spin-lattice measurements show that microcrystalline PbMg{sub 1/3}Nb{sub 2/3}O{sub 3} (PMN) powder is dynamically disordered at room temperature, whereas nanocrystalline PMN powder is orientationally frozen out and long-range ordered at room temperature. The dynamical disorder of the microcrystalline powder results in a motional averaging of the anisotropic part of the {sup 93}Nb chemical shift tensor and second order quadrupole shift, whereas this averaging is absent in the nanocrystalline powder, resulting in a broader central line and a longer spin-lattice relaxation time. This seems to be the first observation of such size effects in a relaxor. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Thinking outside the box: fluctuations and finite size effects

    Science.gov (United States)

    Villamaina, Dario; Trizac, Emmanuel

    2014-05-01

    The isothermal compressibility of an interacting or non-interacting system may be extracted from the fluctuations of the number of particles in a well-chosen control volume. Finite size effects are prevalent and should be accounted for to obtain a meaningful, thermodynamic compressibility. In the traditional computational setup, where a given simulation box is replicated with periodic boundary conditions, we study particle number fluctuations outside the box (i.e. when the control volume exceeds the box itself), which bear relevant thermodynamic information. We also investigate the related problem of extracting the compressibility from the structure factor in the small wave-vector limit (k → 0). The calculation should be restricted to the discrete set of wave-vectors k that are compatible with the periodicity of the system, and we assess the consequences of considering other k values, a widespread error among beginners.

  16. Effects of Breakdown, Backlog and Rework on Replenishment Lot Size

    Directory of Open Access Journals (Sweden)

    Tsu-Ming Yeh

    2012-11-01

    Full Text Available This study studies the effects of machine breakdown, backlog and rework on the replenishment lot size. In real-life manufacturing systems, random defective rate and breakdown of equipment are inevitable. When backlogging is permitted during a production run, a random machine failure may take place either in backlog filling stage or in inventory piling time; this study focuses on the former situation and considers all defective items produced are repairable through a rework process. The objective of this study is to determine the optimal run time that minimizes the long-run average production-inventory costs. The result can be directly applied to the practical production planning and control field to assist practitioner in production management cost reduction.

  17. Effect of chip size on steam explosion pretreatment of softwood.

    Science.gov (United States)

    Ballesteros, I; Oliva, J M; Navarro, A A; González, A; Carrasco, J; Ballesteros, M

    2000-01-01

    Although considerable progress has been made in technology for converting lignocellulosic biomass into ethanol, substantial opportunities still exist to reduce production costs. In biomass pretreatment, reducing milling power is a technological improvement that will substantially lower production costs for ethanol. Improving sugar yield from hemicellulose hydrolysis would also reduce ethanol production costs. Thus, it would be desirable to test innovative pretreatment conditions to improve the economics by reducing electrical power of the milling stage and by optimizing pretreatment recovery of hemicellulose, as well as to enhance cellulose hydrolysis. The objective of this study was to evaluate the effect of chip size (2-5, 5-8, and 8-12 mm) on steam-explosion pretreatment (190 and 210 degrees C, 4 and 8 min) of softwood (Pinus pinaster).

  18. Finite-size effects for percolation on Apollonian networks.

    Science.gov (United States)

    Auto, Daniel M; Moreira, André A; Herrmann, Hans J; Andrade, José S

    2008-12-01

    We study the percolation problem on the Apollonian network model. The Apollonian networks display many interesting properties commonly observed in real network systems, such as small-world behavior, scale-free distribution, and a hierarchical structure. By taking advantage of the deterministic hierarchical construction of these networks, we use the real-space renormalization-group technique to write exact iterative equations that relate percolation network properties at different scales. More precisely, our results indicate that the percolation probability and average mass of the percolating cluster approach the thermodynamic limit logarithmically. We suggest that such ultraslow convergence might be a property of hierarchical networks. Since real complex systems are certainly finite and very commonly hierarchical, we believe that taking into account finite-size effects in real-network systems is of fundamental importance.

  19. Effect of tube size on electromagnetic tube bulging

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The commercial finite code ANSYS was employed for the simulation of the electromagnetic tube bulging process. The finite element model and boundary conditions were thoroughly discussed. ANSYS/EMAG was used to model the time varying electromagnetic field in order to obtain the radial and axial magnetic pressure acting on the tube. The magnetic pressure was then used as boundary conditions to model the high velocity deformation of various length tube with ANSYS/LSDYNA. The time space distribution of magnetic pressure on various length tubes was presented. Effect of tube size on the distribution of radial magnetic pressure and axial magnetic pressure and high velocity deformation were discussed. According to the radial magnetic pressure ratio of tube end to tube center and corresponding dimensionless length ratio of tube to coil, the free electromagnetic tube bulging was studied in classification. The calculated results show good agreements with practice.

  20. 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.

  1. Impact of vaccine economic programs on physician referral of children to public vaccine clinics: a pre-post comparison

    Directory of Open Access Journals (Sweden)

    Troy Judith A

    2006-01-01

    Full Text Available Abstract Background The Vaccines for Children (VFC Program is a major vaccine entitlement program with limited long-term evaluation. The objectives of this study are to evaluate the effect of VFC on physician reported referral of children to public health clinics and on doses administered in the public sector. Methods Minnesota and Pennsylvania primary care physicians (n = 164, completed surveys before (e.g., 1993 and after (2003 VFC, rating their likelihood on a scale of 0 (very unlikely to 10 (very likely of referring a child to the health department for immunization. Results The percentage of respondents likely to refer was 60% for an uninsured child, 14% for a child with Medicaid, and 3% for a child with insurance that pays for immunization. Half (55% of the physicians who did not participate in VFC were likely to refer a Medicaid-insured child, as compared with 6% of those who participated (P P P = 0.001. Conclusion Reported out-referral to public clinics decreased over time. In light of increasing immunizations rates, this suggests that more vaccines were being administered in private provider offices.

  2. Improved Childhood Diarrhea Treatment Practices in Ghana: A Pre-Post Evaluation of a Comprehensive Private-Sector Program.

    Science.gov (United States)

    El-Khoury, Marianne; Banke, Kathryn; Sloane, Phoebe

    2016-06-20

    Diarrhea is the fourth leading cause of child mortality in Ghana. In 2010, Ghana endorsed guidelines from the World Health Organization and the United Nations Children's Fund for use of zinc with low-osmolarity oral rehydration salts (ORS) for the treatment of acute childhood diarrhea. From late 2011 through 2014, the Strengthening Health Outcomes through the Private Sector (SHOPS) project implemented a comprehensive program in 3 regions of Ghana to increase the availability and use of ORS and zinc and to decrease incorrect use of antibiotics and antidiarrheals. The program included (1) partnering with local pharmaceutical firms to introduce and market locally produced zinc products, (2) collaborating with the Ghanaian Pharmacy Council to provide training and supportive supervision of private-sector providers on diarrhea management, and (3) conducting mass media campaigns to raise caregiver awareness. We evaluated the effect of this program using a baseline survey of 754 caregivers of children under 5 with diarrhea at the start of the intervention in 2012 and a follow-up survey of 751 caregivers in 2014. Regression analysis showed that use of ORS with zinc increased from 0.8% in 2012 to 29.2% in 2014 (P<.001), and antibiotic use declined from 66.2% to 38.2% (P<.001) during the same period. The magnitude and statistical significance of these results remained the same after including potential confounding factors as covariates. Inappropriate antibiotic use, however, remained high at follow-up. We conclude that similar programs applied in other settings have the potential to rapidly scale up use of ORS and zinc. Additional efforts are required to reduce persistent incorrect antibiotic use.

  3. Knife mill operating factors effect on switchgrass particle size distributions.

    Science.gov (United States)

    Bitra, Venkata S P; Womac, Alvin R; Yang, Yuechuan T; Igathinathane, C; Miu, Petre I; Chevanan, Nehru; Sokhansanj, Shahab

    2009-11-01

    Biomass particle size impacts handling, storage, conversion, and dust control systems. Switchgrass (Panicum virgatum L.) particle size distributions created by a knife mill were determined for integral classifying screen sizes from 12.7 to 50.8 mm, operating speeds from 250 to 500 rpm, and mass input rates from 2 to 11 kg/min. Particle distributions were classified with standardized sieves for forage analysis that included horizontal sieving motion with machined-aluminum sieves of thickness proportional to sieve opening dimensions. Then, a wide range of analytical descriptors were examined to mathematically represent the range of particle sizes in the distributions. Correlation coefficient of geometric mean length with knife mill screen size, feed rate, and speed were 0.872, 0.349, and 0.037, respectively. Hence, knife mill screen size largely determined particle size of switchgrass chop. Feed rate had an unexpected influence on particle size, though to a lesser degree than screen size. The Rosin-Rammler function fit the chopped switchgrass size distribution data with an R(2)>0.982. Mass relative span was greater than 1, which indicated a wide distribution of particle sizes. Uniformity coefficient was more than 4.0, which indicated a large assortment of particles and also represented a well-graded particle size distribution. Knife mill chopping of switchgrass produced 'strongly fine skewed mesokurtic' particles with 12.7-25.4 mm screens and 'fine skewed mesokurtic' particles with 50.8 mm screen. Results of this extensive analysis of particle sizes can be applied to selection of knife mill operating parameters to produce a particular size of switchgrass chop, and will serve as a guide for relations among the various analytic descriptors of biomass particle distributions.

  4. Exploration of the impacts of distributed-site Research Experiences for Undergraduates using pre-/post- student interviews

    Science.gov (United States)

    Colella, H.; Hubenthal, M.; Brudzinski, M. R.

    2013-12-01

    The benefits for student participants of undergraduate research opportunities have been well documented. However, advancements in information and communications technologies (ICT) and cultural shifts around online education and virtual peer-to-peer interaction have lead to new models in which to structure such experiences. Currently, these ICT-enabled Research Experiences for Undergraduates (REU) programs connect geographically distributed interns in supportive e-learning communities while maintaining a traditional local mentoring arrangement. To document and explore the effects of distributed REU Sites in more depth, six interns from such a program, the Incorporated Research Institution for Seismology (IRIS) REU, were selected at random and asked to be interviewed about the REU experience. The primary targets of the interviews are to understand the mentor/mentee relationships, feeling of support and development and value of near-peer and far-peer relationships throughout their internship in a distributed REU program, and whether they receive the training necessary to gain confidence as a researcher. We also examine the various communication technologies as well as best practices and strategies that can increase intern connectedness. Pre-internship interviews were conducted in-person at the start of the centralized internship orientation week, while post-internship interviews were virtual (e.g. video chat with Skype or Google Hangout). These semi-structured interviews have full audio recordings and subsequent transcriptions. An additional, virtual follow-up interview will be conducted next spring after the interns have an opportunity to attend and present their research at a national conference (e.g., AGU). Interview material will be analyzed through a process of coding, sorting, local integration, and inclusive integration. Results will also be triangulated with pre- and post- survey data both from participants and other survey data from previous years of the IRIS

  5. Effect of Pupil Size on Wavefront Refraction during Orthokeratology.

    Science.gov (United States)

    Faria-Ribeiro, Miguel; Navarro, Rafael; González-Méijome, José Manuel

    2016-11-01

    It has been hypothesized that central and peripheral refraction, in eyes treated with myopic overnight orthokeratology, might vary with changes in pupil diameter. The aim of this work was to evaluate the axial and peripheral refraction and optical quality after orthokeratology, using ray tracing software for different pupil sizes. Zemax-EE was used to generate a series of 29 semi-customized model eyes based on the corneal topography changes from 29 patients who had undergone myopic orthokeratology. Wavefront refraction in the central 80 degrees of the visual field was calculated using three different quality metrics criteria: Paraxial curvature matching, minimum root mean square error (minRMS), and the Through Focus Visual Strehl of the Modulation Transfer Function (VSMTF), for 3- and 6-mm pupil diameters. The three metrics predicted significantly different values for foveal and peripheral refractions. Compared with the Paraxial criteria, the other two metrics predicted more myopic refractions on- and off-axis. Interestingly, the VSMTF predicts only a marginal myopic shift in the axial refraction as the pupil changes from 3 to 6 mm. For peripheral refraction, minRMS and VSMTF metric criteria predicted a higher exposure to peripheral defocus as the pupil increases from 3 to 6 mm. The results suggest that the supposed effect of myopic control produced by ortho-k treatments might be dependent on pupil size. Although the foveal refractive error does not seem to change appreciably with the increase in pupil diameter (VSMTF criteria), the high levels of positive spherical aberration will lead to a degradation of lower spatial frequencies, that is more significant under low illumination levels.

  6. Particle Size Effect in Granular Composite Aluminum/tungsten

    Science.gov (United States)

    Chiu, Po-Hsun; Wang, Sophia; Vitali, Efrem; Herbold, Eric B.; Benson, David J.; Nesterenko, Vitali F.

    2009-12-01

    Compressive dynamic strength and fracture pattern of Al-W granular composites with an identical weight ratio of Al (23.8 wt%) and W (76.2 wt%) with different porosities, size and shape of W component were investigated at strain rates 1000-1500 l/s. Samples were fabricated by Cold Isostatic Pressing. A dynamic strength of composites with fine W particles (100 MPa) was significantly larger than the strength of composite with the coarse W particles (75 MPa) at the same porosity 26% (samples with porosity 15% with coarse W particles exhibited a higher strength of 175 MPa). Morphology of W inclusions had a strong effect on dynamic strength. Samples with W wires arranged in axial direction (diameter 100 microns) and porosity 16%) with the same volume content of components had a dynamic strength of 350 MPa. Dynamic behavior was numerically simulated using computer code Raven, demonstrating a strain hardening effect due to in situ densification which was observed experimentally for cold isostatically pressed Al and Al-coarse W powders.

  7. The other half of the story: effect size analysis in quantitative research.

    Science.gov (United States)

    Maher, Jessica Middlemis; Markey, Jonathan C; Ebert-May, Diane

    2013-01-01

    Statistical significance testing is the cornerstone of quantitative research, but studies that fail to report measures of effect size are potentially missing a robust part of the analysis. We provide a rationale for why effect size measures should be included in quantitative discipline-based education research. Examples from both biological and educational research demonstrate the utility of effect size for evaluating practical significance. We also provide details about some effect size indices that are paired with common statistical significance tests used in educational research and offer general suggestions for interpreting effect size measures. Finally, we discuss some inherent limitations of effect size measures and provide further recommendations about reporting confidence intervals.

  8. SIZE EFFECT AND GEOMETRICAL EFFECT OF SOLIDS IN MICRO-INDENTATION TEST

    Institute of Scientific and Technical Information of China (English)

    魏悦广; 王学峥; 赵满洪; 郑哲敏; 白以龙

    2003-01-01

    Micro-indentation tests at scales of the order of sub-micron show that the measured hardness increases strongly with decreasing indent depth or indent size, which is frequently referred to as the size effect. At the same time, at micron or sub-micron scale, another effect, which is referred to as the geometrical size effects such as crystal grain size effect, thin film thickness effect, etc., also influences the measured material hardness. However, the trends are at odds with the size-independence implied by the conventional elastic-plastic theory. In the present research, the strain gradient plasticity theory (Fleck and Hutchinson) is used to model the composition effects (size effect and geometrical effect) for polycrystal material and metal thin film/ceramic substrate systems when materials undergo micro-indenting. The phenomena of the "pile-up" and "sink-in" appeared in the indentation test for the polycrystal materials are also discussed. Meanwhile, the micro-indentation experiments for the polycrystal A1 and for the Ti/Si3N4 thin film/substrate system are carried out. By comparing the theoretical predictions with experimental measurements, the values and the variation trends of the micro-scale parameter included in the strain gradient plasticity theory are predicted.

  9. Size speed bias or size arrival effect-How judgments of vehicles' approach speed and time to arrival are influenced by the vehicles' size.

    Science.gov (United States)

    Petzoldt, Tibor

    2016-10-01

    Crashes at railway level crossings are a key problem for railway operations. It has been suggested that a potential explanation for such crashes might lie in a so-called size speed bias, which describes the phenomenon that observers underestimate the speed of larger objects, such as aircraft or trains. While there is some evidence that this size speed bias indeed exists, it is somewhat at odds with another well researched phenomenon, the size arrival effect. When asked to judge the time it takes an approaching object to arrive at a predefined position (time to arrival, TTA), observers tend to provide lower estimates for larger objects. In that case, road users' crossing decisions when confronted with larger vehicles should be rather conservative, which has been confirmed in multiple studies on gap acceptance. The aim of the experiment reported in this paper was to clarify the relationship between size speed bias and size arrival effect. Employing a relative judgment task, both speed and TTA estimates were assessed for virtual depictions of a train and a truck, using a car as a reference to compare against. The results confirmed the size speed bias for the speed judgments, with both train and truck being perceived as travelling slower than the car. A comparable bias was also present in the TTA estimates for the truck. In contrast, no size arrival effect could be found for the train or the truck, neither in the speed nor the TTA judgments. This finding is inconsistent with the fact that crossing behaviour when confronted with larger vehicles appears to be consistently more conservative. This discrepancy might be interpreted as an indication that factors other than perceived speed or TTA play an important role for the differences in gap acceptance between different types of vehicles.

  10. Effect of particle size on lead absorption from the gut

    Energy Technology Data Exchange (ETDEWEB)

    Barltrop, D.; Meek, F.

    1979-07-01

    The relationship between particle size and absorption of lead particles from the gastrointestinal tract of the rat has been investigated. Preparations of metallic lead of particle size between 0. and 250..mu.. were incorporated in laboratory rat diets and absorption determined by measurement of tissue lead concentrations attained under standard conditions. An inverse relationship was found between particle size and lead absorption; this relationship was most marked in the 0 to 100..mu.. range. A five-fold enhancement of absorption was observed from the diet with lead particles of mean size 6..mu.., compared with 197..mu.. particle size. Lead absorption from dried paint films containing lead chromate and lead octoate was measured using a similar technique. a marked enhancement of absorption was observed for both paints when particle size was reduced from 500 to 1000..mu.. to < 50..mu...

  11. Effects of Meaning and Symmetry on Judgments of Size

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...... 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...

  12. Heater size effect on subcooled pool boiling of FC-72

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Rishi; Kim, Jungho [University of Maryland, College Park, MD (United States). Dept. of Mechanical Engineering

    2009-07-01

    Extensive research has been conducted on pool boiling using heaters larger than the capillary length. For large heaters and/or high gravity conditions, boiling is dominated by buoyancy, and the heat transfer is heater size independent. Much less is known about boiling on small heaters and at low gravity levels. The ratio of heater size L{sub h} to capillary length L{sub c} is an important parameter in the determination of heater size dependence on heat transfer. As the ratio L{sub h}/L{sub c} decreases due to a decrease in either heater size or gravity, surface tension forces become dominant. It is proposed that transition from buoyancy to surface tension dominated boiling occurs when the heater size and bubble departure diameter are of the same order. Previous work in variable gravity with flat surfaces has shown that the heat transfer was heater size independent only when the ratio L{sub h}/L{sub c} was considerably larger than 1. An array of 96 platinum resistance heater elements in a 10 x 10 configuration with individual elements 0.7 x 0.7 mm{sup 2} in size was used to vary heater size and measure the heat transfer. The threshold value of L{sub h}/L{sub c} above which pool boiling is heater size independent was found to be about 2.8. (author)

  13. Grain Constraint and Size Effects in Shape Memory Alloy Microwires

    Science.gov (United States)

    Ueland, Stian Melhus

    Shape memory alloys exhibit interesting and useful properties, such as the shape memory effect and superelasticity. Among the many alloy families that have been shown to exhibit shape memory properties the ones based on copper are interesting because they are relatively inexpensive and show excellent properties when made as single crystals. However, the performance ofthese alloys is severely compromised by the introduction of grain boundaries, to the point where they are too poor for commercial applications. This thesis studies the mechanical properties of fine Cobased wires with a bamboo microstructure, i.e., where triple junctions are absent and grain boundaries run perpendicular to the wire axis. These microwires are not single crystals, but their microstructure is not as complex as that of polycrystals either: we call this new class of shape memory alloys oligocrystals. This thesis seeks to better understand the relationship between microstructure and properties in these alloys through a combination of mechanical testing, in situ experiments and modeling. First, in situ scanning electron microscopy, together with finite element modeling, is used to understand the role of grain constraint on the martensitic transformation. Grain constraints are observed to be much less severe in oligocrystalline wires as compared to polycrystals. Oligocrystalline microwires are then thermomechanically tested and shown to exhibit excellent properties that approach those of single crystals. Next, property evolution during cycling is investigated, revealing training effects as well as fatigue life and fracture. Finally, size effects in damping and transformation morphology are studied and it is shown that a transition from a many-domain to a single domain martensite morphology takes place when the wire diameter is decreased. (Copies available exclusively from MIT Libraries, libraries.mit.edu/docs - docs@mit.edu)

  14. Lensless Ghost Diffraction with Partially Coherent Sources: Effects of the Source Size, Transverse Coherence, Detector Size and Defocusing Length

    Science.gov (United States)

    Lin, Jie; Cheng, Jing

    2011-09-01

    Lensless ghost diffraction with partially coherent sources is investigated theoretically and numerically. Based on the classical optical coherent theory and the Gauss-Shell model of the partially coherent sources, we derive an analytical imaging formula of lensless ghost diffraction (LGD). Using this formula, we can see the effects of the transverse size and coherence of the sources, the detector size and defocusing length on the quality of LGD. Numerical results are presented to show that for different detector sizes and defocusing lengths, high quality LGD can be realized by using sources with appropriate transverse sizes and coherent widths. These findings can be used to choose the optimal parameters in the design of a realistic LGD system.

  15. Size effects in plastic hinges of reinforced concrete members

    NARCIS (Netherlands)

    Bigaj-van Vliet, A.J.; Walraven, J.C.

    2002-01-01

    Reasons for size dependence of rotation capacity of plastic hinges are discussed. The increase of ductility with decreasing member size is interpreted from the viewpoint of fracture mechanics of concrete. The results of the introductory test series on simply supported slender beams loaded in three-p

  16. Size Effects in Plastic Hinges of Reinforced Concrete Members

    NARCIS (Netherlands)

    Bigaj, A.; Walraven, J.C.

    2002-01-01

    Reasons for size dependence of rotation capacity of plastic hinges are discussed. The increase of ductility with decreasing member size is interpreted from the viewpoint of fracture mechanics of concrete. The results of the introductory test series on simply supported slender beams loaded in three-p

  17. 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.

  18. Polychaete Annelid Biomass Size Spectra: The Effects of Hypoxia Stress

    Directory of Open Access Journals (Sweden)

    Fangyuan Qu

    2015-01-01

    Full Text Available Quantitative benthic samples were taken during spring and summer at three locations on the Louisiana continental shelf from 2004 to 2012 to assess the influence of hypoxia on the mean sizes (wet weight of polychaete annelid worms. While the mean body size over the entire study of 64 samples was 3.99 ± 4.66 mg wet weight per individual, the mean ranged from 2.97 ± 2.87 mg during consistently hypoxic conditions (2 mg/L. The variations in size within assemblages were estimated from conventional biomass size spectra (BSS and normalized biomass size spectra (NBSS across a broad range of oxygen concentrations. The decline in size was due to the elimination of large species under hypoxic conditions (<2 mg/L, not a reduction in size within species. At “severe” levels of hypoxia (<1 mg/L, the smallest species also declined in abundance, whereas the ubiquitous “medium-sized” Paraprionospio pinnata flourished. These results suggest that there will be enhanced selection for small sizes and species with enlarged branchial palps such as those in P. pinnata if, as predicted, hypoxia becomes more commonplace in time and space worldwide.

  19. Neutron capture effects and pre-atmospheric sizes of meteoroids

    Institute of Scientific and Technical Information of China (English)

    WANG Daode; LIN Yangting

    2003-01-01

    Excesses of 80Kr and 82Kr, produced by secondary neutron capture effects of 79Br and 81Br, were observed in meteorites. Epithermal neutron flux, Jn (30-300 eV), and fast neutron flux, Jn( > 5 MeV), were determined according to reactions of 79Br(n, γβ80Kr, 81Br(n, γβ82Kr, and 24Mg(n, α)21Ne, respectively. Cosmogenic noble gases of several ordinary chondrites fell in China indicate a positive relationship between Jn (30-300 eV)/Jn ( > 5 MeV) ratio and Jn (30-300 eV). This suggests large pre-atmospheric sizes of the meteorites, and a considerable fraction of the secondary neutrons were slowed down to epithermal energy. According to its relationship with Jn (30-300 eV)/Jn ( > 5 MeV) ratio, the pre-atmospheric minimum radii and masses of several Chinese chondrites were estimated as below: Zhaodong: 60 cm, 3200 kg; Laochengzhen: 23 cm, 490 kg; Suizhou: 31 cm, 450 kg; Xi Ujimgin: 22 cm, 160 kg; Dongtai: 21 cm, 140 kg.

  20. Finite-Size Scaling Effects in Chromia thin films

    Science.gov (United States)

    Echtenkamp, Will; He, Xi; Binek, Christian

    2012-02-01

    Controlling magnetism by electrical means remains a key challenge in the area of spintronics. The use of magnetoelectrically active materials is one of the most promising approaches to this problem. Utilizing Cr2O3 as the magnetoelectric pinning layer in a magnetic heterostructure both temperature assisted and isothermal electrical control of exchange bias have been achieved [1,2]. Interestingly, this ME switching of exchange bias has only been achieved using bulk Cr2O3 crystals, isothermal switching of exchange bias using thin film chromia remains elusive. We investigate the origin of unusually pronounced finite-size scaling effects on the properties of Cr2O3 grown by Molecular Beam Epitaxy; in particular we focus on the different temperature dependencies of the magnetic susceptibility of bulk vs. thin film chromia, the change in Nèel temperatures, and the implications for the magneto electric properties of chromia thin films. [4pt] [1] P. Borisov et al., Phys. Rev. Lett. 94, 117203 (2005).[0pt] [2] X. He et al., Nature Mater. 9, 579 (2010).

  1. 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 monolingu

  2. 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.

  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. 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...

  5. Effect of Cobalt Particle Size on Acetone Steam Reforming

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Junming; Zhang, He; Yu, Ning; Davidson, Stephen; Wang, Yong

    2015-06-11

    Carbon-supported cobalt nanoparticles with different particle sizes were synthesized and characterized by complementary characterization techniques such as X-ray diffraction, N-2 sorption, acetone temperature-programmed desorption, transmission electron microscopy, and CO chemisorption. Using acetone steam reforming reaction as a probe reaction, we revealed a volcano-shape curve of the intrinsic activity (turnover frequency of acetone) and the CO2 selectivity as a function of the cobalt particle size with the highest activity and selectivity observed at a particle size of approximately 12.8nm. Our results indicate that the overall performance of acetone steam reforming is related to a combination of particle-size-dependent acetone decomposition, water dissociation, and the oxidation state of the cobalt nanoparticles.

  6. Finite size effects in the dynamics of opinion formation

    CERN Document Server

    Toral, R; Tessone, Claudio J.; Toral, Raul

    2006-01-01

    For some models of relevance in the social sciences we review some examples in which system size plays an important role in the final outcome of the dynamics. We discuss the conditions under which changes of behavior can appear only when the number of agents in the model takes a finite value. Those changes of behavior can be related to the apparent phase transitions that appear in some physical models. We show examples in the Galam's model of opinion transmission and the Axelrod's model of culture formation stressing the role that the network of interactions has on the main results of both models. Finally, we present the phenomenon of system-size stochastic resonance by which a forcing signal (identified as an advertising agent) is optimally amplified by a population of the right (intermediate) size. Our work stresses the role that the system size has in the dynamics of social systems and the inappropriateness of taking the thermodynamic limit for these systems.

  7. Size effects in the elastic deformation behavior of metallic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Patrick; Peukert, Wolfgang, E-mail: W.Peukert@lfg.uni-erlangen.de [Friedrich-Alexander-University Erlangen-Nuremberg, Institute for Particle Technology (Germany)

    2012-12-15

    In this work, the results of a series of molecular statics simulations to investigate the size dependence of the elastic properties of metallic nanoparticles are presented. The per-atom stiffness tensor was calculated from the derivative of the used embedded atom method potentials and, from it, lower order elastic parameters, such as the Young's modulus or the Poisson ratio. The Young's modulus decayed up to 30 % relative to the bulk values for 2.5 nm small particles, whereas the Poisson ratio showed an increase with decreasing particle size for most materials. Particles with a diameter of 30 nm approached the continuum values to around 1 %, marking the transition to continuum theory. The size-dependent Young's modulus and several other material properties can be described by a simple algebraic function of the number of atoms per particle. By plotting the radial distribution of the local Young's modulus within particles of different size, it is shown that only the outermost 2-3 atomic layers are responsible for the size-dependent change of elastic properties. Within these layers, the average atomic stiffness was found to decay linearly and independent of the particle size.

  8. 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...

  9. 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...

  10. Salud mental en reclusos: un análisis pre-post intervención psicosocial con grupo control de comparación

    Directory of Open Access Journals (Sweden)

    Miguel Jesús Bascón Díaz

    Full Text Available La literatura científica advierte de la elevada presencia de trastornos mentales en el medio penitenciario. Por ello, en este trabajo nos planteamos evaluar la salud psicosocial y la autorregulación de reclusos en relación a un grupo control de participantes no reclusos; adicionalmente tratamos de conocer la incidencia de la variable tiempo de reclusión y analizar el efecto intragrupo pre-post entrenamiento en habilidades sociales y comunicativas. La muestra estuvo compuesta por 20 varones, 10 reclusos (cinco con más de un año de condena y cinco con menos y 10 participantes sin antecedentes delictivos, a los que se les administró el cuestionario de salud GHQ-28 y la escala de autorregulación MAPA. Se aplicó la prueba no paramétrica Mann-Whitney (U para el cálculo de probabilidades y el test de Cramer (V como indicador del tamaño de efecto. Los resultados indicaron que la reclusión no implicó necesariamente peor salud y autorregulación, que el tiempo de condena no ejerció excesiva influencia sobre estas dos dimensiones y que el taller de habilidades sociales no pareció, según el análisis pre-postest, haber producido efectos sobre la salud y la autorregulación de los reclusos. Finalmente, se discuten algunas reflexiones generales así como nuevas propuestas para mejorar actuaciones futuras.

  11. A pre-post test evaluation of the impact of the PELICAN MDT-TME Development Programme on the working lives of colorectal cancer team members

    Science.gov (United States)

    2010-01-01

    Background The PELICAN Multidisciplinary Team Total Mesorectal Excision (MDT-TME) Development Programme aimed to improve clinical outcomes for rectal cancer by educating colorectal cancer teams in precision surgery and related aspects of multidisciplinary care. The Programme reached almost all colorectal cancer teams across England. We took the opportunity to assess the impact of participating in this novel team-based Development Programme on the working lives of colorectal cancer team members. Methods The impact of participating in the programme on team members' self-reported job stress, job satisfaction and team performance was assessed in a pre-post course study. 333/568 (59%) team members, from the 75 multidisciplinary teams who attended the final year of the Programme, completed questionnaires pre-course, and 6-8 weeks post-course. Results Across all team members, the main sources of job satisfaction related to working in multidisciplinary teams; whilst feeling overloaded was the main source of job stress. Surgeons and clinical nurse specialists reported higher levels of job satisfaction than team members who do not provide direct patient care, whilst MDT coordinators reported the lowest levels of job satisfaction and job stress. Both job stress and satisfaction decreased after participating in the Programme for all team members. There was a small improvement in team performance. Conclusions Participation in the Development Programme had a mixed impact on the working lives of team members in the immediate aftermath of attending. The decrease in team members' job stress may reflect the improved knowledge and skills conferred by the Programme. The decrease in job satisfaction may be the consequence of being unable to apply these skills immediately in clinical practice because of a lack of required infrastructure and/or equipment. In addition, whilst the Programme raised awareness of the challenges of teamworking, a greater focus on tackling these issues may have

  12. Defect formation energy in pyrochlore: the effect of crystal size

    Science.gov (United States)

    Wang, Jianwei; Ewing, Rodney C.; Becker, Udo

    2014-09-01

    Defect formation energies of point defects of two pyrochlores Gd2Ti2O7 and Gd2Zr2O7 as a function of crystal size were calculated. Density functional theory with plane-wave basis sets and the projector-augmented wave method were used in the calculations. The results show that the defect formation energies of the two pyrochlores diverge as the size decreases to the nanometer range. For Gd2Ti2O7 pyrochlore, the defect formation energy is higher at nanometers with respect to that of the bulk, while it is lower for Gd2Zr2O7. The lowest defect formation energy for Gd2Zr2O7 is found at 15-20 Å. The different behaviors of the defect formation energies as a function of crystal size are caused by different structural adjustments around the defects as the size decreases. For both pyrochlore compositions at large sizes, the defect structures are similar to those of the bulk. As the size decreases, for Gd2Ti2O7, additional structure distortions appear at the surfaces, which cause the defect formation energy to increase. For Gd2Zr2O7, additional oxygen Frenkel pair defects are introduced, which reduce the defect formation energy. As the size further decreases, increased structure distortions occur at the surfaces, which cause the defect formation energy to increase. Based on a hypothesis that correlates the energetics of defect formation and radiation response for complex oxides, the calculated results suggest that at nanometer range Gd2Ti2O7 pyrochlore is expected to have a lower radiation tolerance, and those of Gd2Zr2O7 pyrochlore to have a higher radiation tolerance. The highest radiation tolerance for Gd2Zr2O7 pyrochlore is expected to be found at ˜2 nanometers.

  13. Piezoelectric Size Effects in a Zinc Oxide Micropillar.

    Science.gov (United States)

    Li, Tao; Li, Yu Tong; Qin, Wei Wei; Zhang, Ping Ping; Chen, Xiao Qiang; Hu, Xue Feng; Zhang, Wei

    2015-12-01

    In this work, the dependence of piezoelectric coefficients (PE) on the size of artificial fabricated ZnO micropillars on Si substrate is investigated. ZnO full film is grown with c-axis orientation and an average grain size of 20 nm at a substrate temperature of 500 °C by pulsed laser ablation. The micropillars with the size range of 1.5 to 7 μm are formed by top-down semiconductor device processing. The PE, characterized by piezoelectric force microscopy (PFM), is found to increase from 18.2 to 46.9 pm/V, when the ZnO pillar size is reduced from 7 to 1.5 μm. The strong PE dependence on ZnO pillar size can be explained by local changes in polarization and reduction of unit cell volume with respect to bulk values. These results have strong implications in the field of energy harvesting, as piezoelectric voltage output scales with the piezoelectric coefficient.

  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...... axial strain at failure in comparison with large-sized samples. The size effect on the behavior of samples became further apparent when the number of geotextile layers was increased or the confining pressure was decreased. In addition, the results indicated that the magnitude of the size effect...

  15. Relative importance of grain boundaries and size effects in thermal conductivity of nanocrystalline materials.

    Science.gov (United States)

    Dong, Huicong; Wen, Bin; Melnik, Roderick

    2014-11-13

    A theoretical model for describing effective thermal conductivity (ETC) of nanocrystalline materials has been proposed, so that the ETC can be easily obtained from its grain size, single crystal thermal conductivity, single crystal phonon mean free path (PMFP), and the Kaptiza thermal resistance. In addition, the relative importance between grain boundaries (GBs) and size effects on the ETC of nanocrystalline diamond at 300 K has been studied. It has been demonstrated that with increasing grain size, both GBs and size effects become weaker, while size effects become stronger on thermal conductivity than GBs effects.

  16. Measuring Effect Sizes: The Effect of Measurement Error. Working Paper 19

    Science.gov (United States)

    Boyd, Donald; Grossman, Pamela; Lankford, Hamilton; Loeb, Susanna; Wyckoff, James

    2008-01-01

    Value-added models in education research allow researchers to explore how a wide variety of policies and measured school inputs affect the academic performance of students. Researchers typically quantify the impacts of such interventions in terms of "effect sizes", i.e., the estimated effect of a one standard deviation change in the variable…

  17. Effects of Transverse Beam Size in Beam Position Monitors

    CERN Document Server

    Kurennoy, S S

    2001-01-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by a displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those produced by a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  18. Effects of transverse beam size in beam position monitors.

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. (Sergey)

    2001-01-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  19. EFFECTS OF TRANSFERSE BEAM SIZE IN BEAM POSITIONS MONITORS

    Energy Technology Data Exchange (ETDEWEB)

    S.S. KURENNOY

    2001-06-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  20. Transverse Beam Size Effects in Beam Position Monitors

    Science.gov (United States)

    Kurennoy, Sergey

    2001-04-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The corrections to BPM signals due to a finite beam size are found analytically for a few particular transverse distributions of the beam current. The results for fields can also be directly applied for calculating the beam coupling impedances of small discontinuities.

  1. 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

  2. The influence of male parr body size and mate competition on fertilization success and effective population size in Atlantic salmon.

    Science.gov (United States)

    Jones, M W; Hutchings, J A

    2001-06-01

    Alternative mating strategies in male Atlantic salmon, Salmo salar, are characterized by variability in body size and mate competition. Controlling breeding numbers of larger, older anadromous males, we examined whether body size of mature male parr influenced fertilization success and whether such an association was affected by mate competition among parr. Variation at three to four hypervariable microsatellite loci was used to determine individual paternity of 53-60 offspring from two or three nests from each experimental treatment. Although individual and total parr reproductive success differed significantly among nests within treatments, there was no relationship between parr size and individual reproductive success at any level of competition when anadromous males were involved. However, in a single treatment having no anadromous male, the influence of body size on parr fertilization success was highly significant. Combining data from all treatments, parr body size was an important predictor of the probability of an individual being involved in spawning. We found a negative relationship between total parr reproductive success and intensity of anadromous male competition. To our knowledge, the present study is the first to estimate the effective number of males from individual fertilization success in fish. Our estimates of Ne should not be taken as absolute and may have a downward bias because we did not sample all nests and we used a proxy for lifetime reproductive success. They do, however, illustrate how mature male parr can greatly increase the effective number of males when the latter is estimated from anadromous individuals alone. Although reproductive success by mature male parr increases the effective number of males, this increase seems likely to be most pronounced in natural populations when the number of anadromous males is low.

  3. 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.

  4. Low thermal-mass LEDs: size effect and limits.

    Science.gov (United States)

    Lu, Shunpeng; Liu, Wei; Zhang, Zi-Hui; Tan, Swee Tiam; Ju, Zhengang; Ji, Yun; Zhang, Xueliang; Zhang, Yiping; Zhu, Binbin; Kyaw, Zabu; Hasanov, Namig; Sun, Xiao Wei; Demir, Hilmi Volkan

    2014-12-29

    In this work, low thermal-mass LEDs (LTM-LEDs) were developed and demonstrated in flip-chip configuration, studying both experimentally and theoretically the enhanced electrical and optical characteristics and the limits. LTM-LED chips in 25 × 25 μm2, 50 × 50 μm2, 100 × 100 μm2 and 200 × 200 μm2 mesa sizes were fabricated and comparatively investigated. Here it was revealed that both the electrical and optical properties are improved by the decreasing chip size due to the reduced thermal mass. With a smaller chip size (from 200 μm to 50 μm), the device generally presents higher current density against the bias and higher power density against the current density. However, the 25 × 25 μm2 device behaves differently, limited by the fabrication margin limit of 10 μm. The underneath mechanisms of these observations are uncovered, and furthermore, based on the device model, it is proven that for a specific flip-chip fabrication process, the ideal size for LTM-LEDs with optimal power density performance can be identified.

  5. Size effects in molecular dynamics thermal conductivity predictions

    Science.gov (United States)

    Sellan, D. P.; Landry, E. S.; Turney, J. E.; McGaughey, A. J. H.; Amon, C. H.

    2010-06-01

    We predict the bulk thermal conductivity of Lennard-Jones argon and Stillinger-Weber silicon using the Green-Kubo (GK) and direct methods in classical molecular dynamics simulations. While system-size-independent thermal conductivities can be obtained with less than 1000 atoms for both materials using the GK method, the linear extrapolation procedure [Schelling , Phys. Rev. B 65, 144306 (2002)] must be applied to direct method results for multiple system sizes. We find that applying the linear extrapolation procedure in a manner consistent with previous researchers can lead to an underprediction of the GK thermal conductivity (e.g., by a factor of 2.5 for Stillinger-Weber silicon at a temperature of 500 K). To understand this discrepancy, we perform lattice dynamics calculations to predict phonon properties and from these, length-dependent thermal conductivities. From these results, we find that the linear extrapolation procedure is only accurate when the minimum system size used in the direct method simulations is comparable to the largest mean-free paths of the phonons that dominate the thermal transport. This condition has not typically been satisfied in previous works. To aid in future studies, we present a simple metric for determining if the system sizes used in direct method simulations are sufficiently large so that the linear extrapolation procedure can accurately predict the bulk thermal conductivity.

  6. Target Size and Luminance Effects on Accommodation and Vergence.

    Science.gov (United States)

    1987-01-01

    st i mu I at ed Voluntary changes in accommodation and verger .( e Sub je(ts have been shown to be able to make vol untarN changes in vergence Oil...v ith a projected cross with smooth sides. This cross ,. Is riide on a 35 mm slide and its size was altered manually i) diaphragm. Both crosses

  7. Effects of size-dependent elasticity on stability of nanotweezers

    Institute of Scientific and Technical Information of China (English)

    A FARROKHABADI; A KOOCHI; A KAZEMI; M ABADYAN

    2014-01-01

    It is well-recognized that the electromechanical response of a nanostructure is affected by its element size. In the present article, the size dependent stability behavior and nanotweezers fabricated from nanowires are investigated by modified couple stress elasticity (MCSE). The governing equation of the nanotweezers is obtained by taking into account the presence of Coulomb and intermolecular attractions. To solve the equation, four techniques, i.e., the modified variational iteration method (MVIM), the monotonic iteration method (MIM), the MAPLE numerical solver, and a lumped model, are used. The variations of the arm displacement of the tweezers versus direct current (DC) voltage are obtained. The instability parameters, i.e., pull-in voltage and deflection of the system, are computed. The results show that size-dependency will affect the stability of the nanotweezers significantly if the diameter of the nanowire is of the order of the length scale. The impact of intermolecular attraction on the size-dependent stability of the system is discussed.

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

    Science.gov (United States)

    2016-05-01

    Bath of an Immiscible Liquid, Physical Review Letters, 110, 264503, 2013 X. Li and R. S. Tankin, Droplet Size Distribution: A Derivation of a...10), 811-823, 1969 C. R. Hoggatt and R. F. Recht, Fracture Behavior of Tubular Bombs , Journal of Applied Physics, 39(3), 1856-1862, 1968

  9. Surface finish effects and the strength-grain size relation in SiC

    Science.gov (United States)

    Cranmer, D. C.; Tressler, R. E.; Bradt, R. C.

    1977-01-01

    The effect of surface finish on the strength-grain size relation was investigated for dense hot-pressed SiC. Failure initiated predominantly via the propagation of extrinsic machining-induced flaws for the range of grain sizes and machining grit sizes studied. These results are consistent with the region of large-grain-size flaw control as delineated by Prochazka and Charles. The severity of machining-induced flaws, relative to the machining grit size, decreased with increasing machining grit size and decreasing SiC grain size.

  10. Effect of size upon metal content of shellfish

    Energy Technology Data Exchange (ETDEWEB)

    Boyden, C.R.

    1977-01-01

    The influence of body size upon whole tissue metal content has been examined for eight elements in a variety of marine and estuarine molluscs. Generally, plotting element content against body weight on a double logarithmic basis produces straight line relationships. The calculated regression slopes for 131 lines fall into two main categories: those around 0.77 and those close to 1.00. In the former cases (e.g. zinc in Mytilus edulis) element concentrations are greatest in the smallest individuals; in the second (e.g. cadmium in M. edulis) concentrations are independent of size. In a few cases (e.g. cadmium in the limpet Patella vulgata) highest concentrations are recorded in the largest individuals. In geographically separate populations of a species from ''clean'' environments, the regression slopes relating element content to body size are consistent for each element. Comparison between populations from ''clean'' and ''contaminated'' environments indicates that the regression slopes may be either constant, e.g. zinc (and probably cadmium) in Ostrea edulis, cadmium and zinc in M. edulis, or variable, e.g. cadmium and zinc in P. vulgata, with increase of slopes in metal elevated environments. Curves on double logarithmic plots were obtained relating copper content to body size in the oysters Crassostrea gigas and O. edulis and the mussel M. edulis introduced to a ''contaminated'' environment. Large individuals of these species require longer than 5 months to equilibrate to exceptionally high environmental concentrations of copper. (The same is true for zinc in c. gigas.) In the single case of cadmium in the scallop Pecten maximus an upward directed curve was obtained relating cadmium content to body size, resulting in exceptionally high cadmium concentrations in large scallops. Steeper slopes, and almost twice as much variability, was recorded when using wet weight data compared with

  11. 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

  12. Effects of YORP-induced rotational fission on the small size end of the Main Belt asteroid size distribution

    Science.gov (United States)

    Rossi, Alessandro; Jacobson, S.; Marzari, F.; Scheeres, D.; Davis, D. R.

    2013-10-01

    From the results of a comprehensive asteroid population evolution model, we conclude that the YORP-induced rotational fission hypothesis has strong repercussions for the small size end of the Main Belt asteroid size frequency distribution. These results are consistent with observed asteroid population statistics. The foundation of this model is the asteroid rotation model of Marzari et al. (2011), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis (i.e. when the rotation rate exceeds a critical value, erosion and binary formation occur). The YORP effect timescale for large asteroids with diameters D > ~6 km is longer than the collision timescale in the Main Belt, thus the frequency of large asteroids is determined by a collisional equilibrium (e.g. Bottke 2005), but for small asteroids with diameters D Morbidelli 2009).

  13. Finite-size effects and percolation properties of Poisson geometries

    Science.gov (United States)

    Larmier, C.; Dumonteil, E.; Malvagi, F.; Mazzolo, A.; Zoia, A.

    2016-07-01

    Random tessellations of the space represent a class of prototype models of heterogeneous media, which are central in several applications in physics, engineering, and life sciences. In this work, we investigate the statistical properties of d -dimensional isotropic Poisson geometries by resorting to Monte Carlo simulation, with special emphasis on the case d =3 . We first analyze the behavior of the key features of these stochastic geometries as a function of the dimension d and the linear size L of the domain. Then, we consider the case of Poisson binary mixtures, where the polyhedra are assigned two labels with complementary probabilities. For this latter class of random geometries, we numerically characterize the percolation threshold, the strength of the percolating cluster, and the average cluster size.

  14. 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.

  15. Scale effects on the variability of the raindrop size distribution

    Science.gov (United States)

    Raupach, Timothy; Berne, Alexis

    2016-04-01

    The raindrop size distribution (DSD) is of utmost important to the study of rainfall processes and microphysics. All important rainfall variables can be calculated as weighted moments of the DSD. Qualitative precipitation estimation (QPE) algorithms and numerical weather prediction (NWP) models both use the DSD in order to calculate quantities such as the rain rate. Often these quantities are calculated at a pixel scale: radar reflectivities, for example, are integrated over a volume, so a DSD for the volume must be calculated or assumed. We present results of a study in which we have investigated the change of support problem with respect to the DSD. We have attempted to answer the following two questions. First, if a DSD measured at point scale is used to represent an area, how much error does this introduce? Second, how representative are areal DSDs calculated by QPE and NWP algorithms of the microphysical process happening inside the pixel of interest? We simulated fields of DSDs at two representative spatial resolutions: at the 2.1x2.1 km2 resolution of a typical NWP pixel, and at the 5x5 km2 resolution of a Global Precipitation Mission (GPM) satellite-based weather radar pixel. The simulation technique uses disdrometer network data and geostatistics to simulate the non-parametric DSD at 100x100 m2 resolution, conditioned by the measured DSD values. From these simulations, areal DSD measurements were derived and compared to point measurements of the DSD. The results show that the assumption that a point represents an area introduces error that increases with areal size and drop size and decreases with integration time. Further, the results show that current areal DSD estimation algorithms are not always representative of sub-grid DSDs. Idealised simulations of areal DSDs produced representative values for rain rate and radar reflectivity, but estimations of drop concentration and characteristic drop size that were often outside the sub-grid value ranges.

  16. Effect of proteins, polysaccharides, and particle sizes on sludge dewaterability

    Institute of Scientific and Technical Information of China (English)

    SHAO Liming; HE Peipei; YU Guanghui; HE Pinjing

    2009-01-01

    Four batch experiments of hydrolysis and acidification were carried out to investigate the distributions of proteins (PN) and polysaccharides (PS) in the sludge, the PN/PS ratio, the particle sizes, and their relationship with sludge dewaterability (as determined by capillary suction time, CST). The sludge flocs were stratified through centrifugation- and ultrasound-based method into four layers: (1) slime, (2) loosely bound extracellular polymeric substances (LB-EPS), (3) tightly bound EPS (TB-EPS), and (4) pellet. The results showed that PN was mainly partitioned in the pellet (80.7%) and TB-EPS (9.6%) layers, while PS distributed evenly in the four layers. During hydrolysis and acidification, PN was transferred from the pellet and TB-EPS layers to the slime layer, but PS had no significant transfer trends. The mean particle sizes of the sludge flocs decreased with hydrolysis and acidification. The pH had a more significant influence on the dewaterability of sludge flocs than temperature. Sludge dewaterability during hydrolysis and acidification processes greatly deteriorated from 9.7 s at raw sludge to 340--450 s under alkaline conditions. However, it was just slightly increased under acidic conditions. Further investigation suggested that CST was affected by soluble PN, soluble PN/PS, and particle sizes of sludge flocs, but was affected slightly by total PN, PS, or PN/PS in the whole sludge flocs and other layers (except slime).

  17. Nonuniversal Finite-Size Effects Near Critical Points

    Science.gov (United States)

    Dohm, V.

    2008-11-01

    We study the finite-size critical behavior of the anisotropic φ4 lattice model with periodic boundary conditions in a d-dimensional hypercubic geometry above, at, and below Tc. Our perturbation approach at fixed d = 3 yields excellent agreement with the Monte Carlo (MC) data for the finite-size amplitude of the free energy of the three-dimensional Ising model at Tc by Mon [Phys. Rev. Lett. 54, 2671 (1985)]. Below Tc a minimum of the scaling function of the excess free energy is found. We predict a measurable dependence of this minimum on the anisotropy parameters. Our theory agrees quantitatively with the non-monotonic dependence of the Binder cumulant on the ferromagnetic next-nearest neighbor (NNN) coupling of the two-dimensional Ising model found by MC simulations of Selke and Shchur [J. Phys. A 38, L739 (2005)]. Our theory also predicts a non-monotonic dependence for small values of the anti-ferromagnetic NNN coupling and the existence of a Lifshitz point at a larger value of this coupling. The tails of the large-L behavior at T ≠ Tc violate both finite-size scaling and universality even for isotropic systems as they depend on the bare four-point coupling of the φ4 theory, on the cutoff procedure, and on subleading long-range interactions.

  18. 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.

  19. Size effects in liquid-phase photo-oxidation of phenol using nanometer-sized TiO 2 catalysts

    Science.gov (United States)

    Liu, S.; Jaffrezic, N.; Guillard, C.

    2008-12-01

    Nanocrystalline anatase TiO 2 particles with different particle size were prepared through sol-gel hydrolysis precipitation of titanium isopropoxide, followed by peptization, reflux or hydrothermal treatment, and were characterized by X-ray diffraction (XRD), UV-vis spectroscopy, and nitrogen physi-adsorption methods. The photocatalytic activities of TiO 2 particles were evaluated by the photocatalytic rate of phenol oxidation. The apparent rate constant of phenol conversion with titania without pretreatment by UV-A irradiation was about 40% lower than that with pretreated titania. This result suggests that UV-A pretreatment of TiO 2 samples prepared by the wet methods is necessary before measuring their photocatalytic activity. An optimal particle size (about 10 nm) exists in the TiO 2 for maximum photocatalytic efficiency. The optimum particle size is a result of competing effects of volume recombination, surface recombination, migration of photogenerated electrons and holes, light absorption, defects and surface area. Though the particles were more or less similar in size, the photocatalytic activity of anatase particles prepared by the wet-chemical method is better than that by the dry method, probably the reason is that the amount of surface adsorbed water and hydroxyl groups of TiO 2 particles decreased after calcination.

  20. 医院员工岗前培训体系设计与实践%Design and Practice of Pre-post Training System for Hospital New Employees

    Institute of Scientific and Technical Information of China (English)

    王洪国; 陈源; 王晶桐; 王杉

    2016-01-01

    新员工岗前培训是医院人才建设的重要途径,是一项系统工程。科学设计岗前培训体系要基于医院和新员工的需求分析,结合医院文化设计培训方案、组织开展系列活动,通过培训考核和满意度调查来提高岗前培训质量,同时还需要与时俱进对培训体系进行调整和完善。%Pre-post training for new employees is an important way for of hospital personnel construction, which is a systematic engineering. Scientific design of pre-post training system should base on the analysis of the needs of hospital and new employees. Training program design should combine hospital culture before carrying out series of activities. Meanwhile, improve pre-post training quality with training examination and satisfaction survey and adjust it timely.

  1. General Framework for Effect Sizes in Cluster Randomized Experiments

    Science.gov (United States)

    VanHoudnos, Nathan

    2016-01-01

    Cluster randomized experiments are ubiquitous in modern education research. Although a variety of modeling approaches are used to analyze these data, perhaps the most common methodology is a normal mixed effects model where some effects, such as the treatment effect, are regarded as fixed, and others, such as the effect of group random assignment…

  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 Ne 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 Ne /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 Ne /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. Effect Size as the Essential Statistic in Developing Methods for mTBI Diagnosis.

    Science.gov (United States)

    Gibson, Douglas Brandt

    2015-01-01

    The descriptive statistic known as "effect size" measures the distinguishability of two sets of data. Distingishability is at the core of diagnosis. This article is intended to point out the importance of effect size in the development of effective diagnostics for mild traumatic brain injury and to point out the applicability of the effect size statistic in comparing diagnostic efficiency across the main proposed TBI diagnostic methods: psychological, physiological, biochemical, and radiologic. Comparing diagnostic approaches is difficult because different researcher in different fields have different approaches to measuring efficacy. Converting diverse measures to effect sizes, as is done in meta-analysis, is a relatively easy way to make studies comparable.

  4. 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.

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

    Science.gov (United States)

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

    2013-07-01

    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.

  6. Size effects in band gap bowing in nitride semiconducting alloys

    DEFF Research Database (Denmark)

    Gorczyca, I.; Suski, T.; Christensen, Niels Egede

    2011-01-01

    Chemical and size contributions to the band gap bowing of nitride semiconducting alloys (InxGa1-xN, InxAl1-xN, and AlxGa1-xN) are analyzed. It is shown that the band gap deformation potentials of the binary constituents determine the gap bowing in the ternary alloys. The particularly large gap bo...... bowing in In-containing nitride alloys can be explained by specific properties of InN, which do not follow trends observed in several other binaries....

  7. Size effects in the Ginzburg-Landau theory

    Science.gov (United States)

    Fiolhais, Miguel C. N.; Birman, Joseph L.

    2015-02-01

    The Ginzburg-Landau theory is analyzed in the case of small dimension superconductors, a couple of orders of magnitude above the coherence length, where the theory is still valid but quantum fluctuations become significant. In this regime, the potential around the expectation value is approximated to a quadratic behavior, and the ground-state is derived from the Klein-Gordon solutions of the Higgs-like field. The ground-state energy is directly compared to the condensation energy, and used to extract new limits on the size of superconductors at zero Kelvin and near the critical temperature.

  8. 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.

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

    Science.gov (United States)

    Torkhov, N. A.; Babak, L. I.; Kokolov, A. A.; Salnikov, A. S.; Dobush, I. M.; Novikov, V. A.; Ivonin, I. V.

    2016-03-01

    Investigations have shown that in the local approximation (for sizes L 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.

  10. Size effects of effective Young’s modulus for periodic cellular materials

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    With the wide demands of cellular materials applications in aerospace and civil engineering,research effort sacrificed for this type of materials attains nowadays a higher level than ever before.This paper is focused on the prediction methods of effective Young’s modulus for periodical cellular materials.Based on comprehensive studies of the existing homogenization method(HM),the G-A meso-mechanics method(G-A MMM) and the stretching energy method(SEM) that are unable to reflect the size effect,we propose the bending energy method(BEM) for the first time,and a comparative study of these four methods is further made to show the generality and the capability of capturing the size effect of the BEM method.Meanwhile,the underlying characteristics of each method and their relations are clarified.To do this,the detailed finite element computing and existing experimental results of hexagonal honeycombs from the literature are adopted as the standard of comparison for the above four methods.Stretch and bending models of periodical cellular materials are taken into account,respectively for the comparison of stretch and flexural displacements resulting from the above methods.We conclude that the BEM has the strong ability of both predicting the effective Young’s modulus and revealing the size effect.Such a method is also able to predict well the variations of structural displacements in terms of the cell size under stretching and bending loads including the non-monotonous variations for the hexagonal cell.On the contrary,other three methods can only predict the limited results whenever the cell size tends to be infinitely small.

  11. "PowerUp"!: A Tool for Calculating Minimum Detectable Effect Sizes and Minimum Required Sample Sizes for Experimental and Quasi-Experimental Design Studies

    Science.gov (United States)

    Dong, Nianbo; Maynard, Rebecca

    2013-01-01

    This paper and the accompanying tool are intended to complement existing supports for conducting power analysis tools by offering a tool based on the framework of Minimum Detectable Effect Sizes (MDES) formulae that can be used in determining sample size requirements and in estimating minimum detectable effect sizes for a range of individual- and…

  12. Surfactant effects in magnetite nanoparticles of controlled size

    Energy Technology Data Exchange (ETDEWEB)

    Guardia, P. [Departament de Fisica Fonamental and Institut de Nanociencia i Nanotecnologia (IN2UB) , Universitat de Barcelona, Marti i Franques 1, 08028- Barcelona, Catalonia (Spain); Batlle-Brugal, B. [Departament de Fisica Fonamental and Institut de Nanociencia i Nanotecnologia (IN2UB) , Universitat de Barcelona, Marti i Franques 1, 08028- Barcelona, Catalonia (Spain); Roca, A.G. [Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Ines de la Cruz 3, Cantoblanco 28049, Madrid (Spain); Iglesias, O. [Departament de Fisica Fonamental and Institut de Nanociencia i Nanotecnologia (IN2UB) , Universitat de Barcelona, Marti i Franques 1, 08028- Barcelona, Catalonia (Spain); Morales, M.P. [Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Ines de la Cruz 3, Cantoblanco 28049, Madrid (Spain); Serna, C.J. [Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juana Ines de la Cruz 3, Cantoblanco 28049, Madrid (Spain); Labarta, A. [Departament de Fisica Fonamental and Institut de Nanociencia i Nanotecnologia (IN2UB) , Universitat de Barcelona, Marti i Franques 1, 08028- Barcelona, Catalonia (Spain); Batlle, X. [Departament de Fisica Fonamental and Institut de Nanociencia i Nanotecnologia (IN2UB) , Universitat de Barcelona, Marti i Franques 1, 08028- Barcelona, Catalonia (Spain)]. E-mail: xavier@ffn.ub.es

    2007-09-15

    Magnetite Fe{sub 3}O{sub 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{sub 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{sub 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.

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

    Science.gov (United States)

    Konstantopoulos, Spyros; Shen, Ting

    2016-01-01

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

  14. Temperature effects on body size of freshwater crustacean zooplankton from Greenland to the tropics

    NARCIS (Netherlands)

    Havens, K.E.; Motta Pinto- Coelho, R.; Beklioglu, M.; Christoffersen, K.S.; Jeppesen, E.; Lauridsen, T.; Mazumder, A.; Méthot, G.; Pinel Alloul, B.; Tavşanoğlu, U.N.; Erdoğan, S.; Vijverberg, J.

    2015-01-01

    The body size of zooplankton has many substantive effects on the function of aquatic food webs. A variety of factors may affect size, and earlier studies indicate that water temperature may be a particularly important variable. Here we tested the hypothesis that the body size of cladocerans,

  15. The effect of retinal size on the perception of distance in photographs.

    Science.gov (United States)

    Takezawa, Tomomi

    2011-01-01

    The effect of the retinal size of a target on the perception of absolute distance to a single target and relative distance between near and far targets was examined with photographic displays including two persons. Retinal size was systematically varied by varying the focal length of the camera lens, the display size, and the viewing distance. The results showed that, although the relationship between the perceived absolute distance and retinal size was not inversely proportional, the perceived absolute distance decreased with an increase in retinal size. This was more evident when the retinal size was changed by varying the focal length. These results suggest that the determinants of the perceived absolute distance were not only the retinal size of the target but also its ratio to the overall display. The results also showed that the perceived relative distances were little influenced by retinal size, but were strongly dependent on the size ratio of the two targets in the display.

  16. Average and Heterogeneous Effects of Class Size on Educational Achievement in Lesotho

    OpenAIRE

    2015-01-01

    Understanding class size effects on educational achievement remains a preoccupation of many economists. But empirical results are, to this far, still inconclusive. I use the two-stage least squares and the instrumental variable quantile regression methods on Lesotho’s grade 6 students maths and reading test scores to estimate, respectively, the mean and distributional effects of class size. I find strong evidence for putative class size effects on reading achievement, but not on maths achie...

  17. Effect of Mixture Pressure and Equivalence Ratio on Detonation Cell Size for Hydrogen-Air Mixtures

    Science.gov (United States)

    2015-06-01

    EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR MIXTURES...protection in the United States. AFIT-ENY-MS-15-J-045 EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR...DISTRIBUTION UNLIMITED. AFIT-ENY-MS-15-J-045 EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR MIXTURES

  18. LES of certain droplet size effects in fuel sprays

    Energy Technology Data Exchange (ETDEWEB)

    Vuorinen, V. A.

    2010-07-01

    This thesis belongs to the field of mechanical engineering, more precisely to computational fluid dynamics and fuel injection modelling. This type of problems have been extensively studied because of their practical importance, for example, in combustion processes of automotive industry. Novel challenges are reduction of exhaust gas emissions in the present diesel fuel-based and also in bio diesel-based concepts. The problem studied in this work is of generic nature and it can be related to many real world problems. A model problem of droplet-laden jet is studied to emulate a fuel spray. The most essential parameter that is studied is fuel droplet size. More precisely, the ratio of droplet timescale and fluid timescale i.e. the Stokes number. Mathematically, the studied system can be formulated in terms of the Navier-Stokes equation with a spray momentum source term at low Mach number regime. A feature characteristic to this study is to use large scale computer simulation to simulate the system. For adequate modelling, this work makes use of a method called Large-Eddy Simulation (LES) to simulate the motion of the turbulent gas and Lagrangian Particle Tracking (LPT) to simulate the motion of the droplets. The main computational tool used in this work is the OpenFOAM software. In fact, the present work is one of the first computational studies on LES/LPT diesel spray modeling in which droplet-level phenomena are discussed in light of the global behavior of the spray jet in an extensive manner. In view of the literature on this topic the results of the work seem to be realistic. The dependence of spray shape on droplet size (Stokes number) is studied and differences between the shapes are consistently explained. It is noted that mixing inside the spray depends significantly on the fuel droplet size. Quantitative and statistical analysis methods are developed in order to explain the connection between spray shape and mixing. The presented analysis explains the results

  19. Beyond Cohen's "d": Alternative Effect Size Measures for Between-Subject Designs

    Science.gov (United States)

    Peng, Chao-Ying Joanne; Chen, Li-Ting

    2014-01-01

    Given the long history of discussion of issues surrounding statistical testing and effect size indices and various attempts by the American Psychological Association and by the American Educational Research Association to encourage the reporting of effect size, most journals in education and psychology have witnessed an increase in effect size…

  20. 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.

  1. Finite size effect on dynamical entanglement entropy: CFT and holography

    CERN Document Server

    Mandal, Gautam; Ugajin, Tomonori

    2016-01-01

    Time-dependent entanglement entropy (EE) is computed for a single interval in two-dimensional conformal theories from a quenched initial state in the presence of spatial boundaries. The EE is found to be periodic in time with periodicity equal to the system size $L$. For large enough $L$, the EE shows a rise to a thermal value (characterized by a temperature $1/\\beta$ determined by the initial state), followed by periodic returns to the original value. This works irrespective of whether the conformal field theory (CFT) is rational or irrational. For conformal field theories with a holographic dual, the large $c$ limit plays an essential role in ensuring that the EE computed from the CFT is universal (independent of the details of the CFT and of boundary conditions) and is exactly matched by the holographic EE. The dual geometry is computed and it interpolates between a BTZ black hole at large $L$ and global AdS at large $\\beta$.

  2. Fumonisin production on irradiated corn kernels: effect of inoculum size.

    Science.gov (United States)

    Chulze, S N; Etcheverry, M G; Lecumberry, S E; Magnoli, C E; Dalcero, A M; Ramirez, M L; Pascale, M; Rodriguez, M I

    1999-07-01

    Production of fumonisins B1, B2, and B3 by Fusarium moniliforme was evaluated on irradiated corn kernels inoculated with different spore concentrations (10, 10(2), 10(3), 10(5), and 10(6)), a water activity of 0.97, and a temperature of 25 degrees C. There was a direct relationship between the level of toxin produced and inoculum size. The highest levels of total fumonisin produced after 35 days of incubation were 5,028 and 9,063 ng/g at 10(5) and 10(6) spores per ml, respectively. The pattern of fumonisin production (FB1 > FB2 > FB3) in cultures growing from different inocula was not affected during the 35 days of incubation. The ratio between FB2 and FB1 varied from 0.15 to 0.42, whereas the ratio between FB3 and FB1 varied from 0.34 to 0.87.

  3. Physical mechanism of the linear beam-size effect at colliders

    Energy Technology Data Exchange (ETDEWEB)

    Melnikov, K. [Institut fuer Physik, THEP, Johannes Gutenberg Universitaet, Staudinger weg 7, D 55099 Mainz (Germany); Kotkin, G.L.; Serbo, V.G. [Novosibirsk State University, 630090, Novosibirsk (Russia)

    1996-09-01

    We present a qualitative but precise description of the linear beam-size effect predicted for the processes in which unstable but long-living particles collide with each other. We derive a physically pronounced equation for the event rate which proves that the linear beam-size effect corresponds to the scattering of one beam of particles on the decay products of the other. We compare this linear beam-size effect with the known logarithmic beam-size effect measured in the experiments on a single bremsstrahlung at Novosibirsk{close_quote}s VEPP-4 and DESY HERA. {copyright} {ital 1996 The American Physical Society.}

  4. Physical mechanism of the linear beam-size effect at colliders

    CERN Document Server

    Melnikov, K; Serbo, V G

    1996-01-01

    We present qualitative but precise description of the linear beam-size effect predicted for the processes in which unstable but long--living particles collide with each other. We derive physically pronounced equation for the events rate which proves that the linear beam-size effect corresponds to the scattering of one beam of particles on the decay products of the other. We compare this linear beam-size effect with the known logarithmic beam-size effect measured in the experiments on a single bremsstrahlung at VEPP-4 and HERA.

  5. Grain Size Effect on Fracture Behavior of the Axis-Tensile Test of Inconel 718 Sheet

    Science.gov (United States)

    Liu, B. B.; Han, J. Q.; Zhao, R.; Liu, W.; Wan, M.

    2016-11-01

    Change in mechanical parts from macro-size to micro-size has become a trend in the metal- and alloy-forming process, with an increasing demand on micro-parts in the last decades. The material mechanical behaviors of micro-size parts are quite different from the conventional ones of macro-size parts due to size effect. It is necessary to further investigate the effects of grain size on material mechanisms in micro-scales, especially fracture behaviors. The fracture behaviors of Inconel 718 sheet with the thickness of 300 μm are studied by uniaxial tensile tests in different grain sizes ranging from 18 to 130 μm. The results show that fracture stress and strain decrease with the increase of grain size. A critical value in the specimen thickness (t) to grain size (d) ratio divides the strength levels into separate stages on the basis of an increase of the inverse of grain size. In addition, the grain size-dependent fracture morphology is changed in the number of dimples and micro-voids decreasing on the fracture surfaces and the sizes of micro-voids changing larger with the increase of grain size.

  6. Effects of Nanoparticle Size and Morphology on IR Diffuse Reflection Spectra

    Institute of Scientific and Technical Information of China (English)

    KONG Xiao-dong; ZHU Mei-wu; ZHENG Jia-sheng

    2003-01-01

    Two kinds of nanopowders were studied. One is NiFe2O4 spherical nanopowders which have different particle sizes. Another is ZnO nanopowders including two series of spherical particles and tetrapod nanowhiskers. Through measuring the infrared diffuse reflection spectra of nanopowders, it can be found that the particle size and morphology affect the infrared diffuse reflection spectra. For the NiFe2O4 nanopowders the smaller the particle size, the larger the K-M value. And when the particle size is large enough , the effect of the particle size on infrared diffuse reflection spectra would disappear. For the ZnO nanopowders the effects of the particle size and morphology are more special. The effect of the particle sizes of tetrapod whisker nanopowders on infrared diffuse reflection spectra is more than that of spherical nanopowders.

  7. Galaxy Clusters in the Line of Sight to Background Quasars: II. Environmental effects on the sizes of baryonic halo sizes

    CERN Document Server

    Padilla, N; López, S; Barrientos, L F; Lira, P; Andrews, H; Tejos, N

    2009-01-01

    Based on recent results on the frequency of MgII absorption line systems in the "QSO behind RCS clusters" survey (QbC), we analyse the effects of the cluster environment on the sizes of baryonic haloes around galaxies. We use two independent models, i) an empirical halo occupation model which fits current measurements of the clustering and luminosity function of galaxies at low and high redshifts, and ii) the GALFORM semi-analytic model of galaxy formation, which follows the evolution of the galaxy population from first principles, adjusted to match the statistics of low and high redshift galaxies. In both models we constrain the MgII halo sizes of field and cluster galaxies using observational results on the observed MgII statistics. Our results for the field are in good agreement with previous works, indicating a typical \\mgii\\ halo size of $r_MgII ~ 50h_71^-1kpc in the semi-analytic model, and slightly lower in the halo occupation number approach. For the cluster environment, we find that both models requi...

  8. Safety and efficacy of at-home robotic locomotion therapy in individuals with chronic incomplete spinal cord injury: a prospective, pre-post intervention, proof-of-concept study.

    Directory of Open Access Journals (Sweden)

    Rüdiger Rupp

    Full Text Available The compact Motorized orthosis for home rehabilitation of Gait (MoreGait was developed for continuation of locomotion training at home. MoreGait generates afferent stimuli of walking with the user in a semi-supine position and provides feedback about deviations from the reference walking pattern.Prospective, pre-post intervention, proof-of-concept study to test the feasibility of an unsupervised home-based application of five MoreGait prototypes in subjects with incomplete spinal cord injury (iSCI.Twenty-five (5 tetraplegia, 20 paraplegia participants with chronic (mean time since injury: 5.8 ± 5.4 (standard deviation, SD years sensorimotor iSCI (7 ASIA Impairment Scale (AIS C, 18 AIS D; Walking Index for Spinal Cord Injury (WISCI II: Interquartile range 9 to 16 completed the training (45 minutes / day, at least 4 days / week, 8 weeks. Baseline status was documented 4 and 2 weeks before and at training onset. Training effects were assessed after 4 and 8 weeks of therapy.After therapy, 9 of 25 study participants improved with respect to the dependency on walking aids assessed by the WISCI II. For all individuals, the short-distance walking velocity measured by the 10-Meter Walk Test showed significant improvements compared to baseline (100% for both self-selected (Mean 139.4% ± 35.5% (SD and maximum (Mean 143.1% ± 40.6% (SD speed conditions as well as the endurance estimated with the six-minute walk test (Mean 166.6% ± 72.1% (SD. One device-related adverse event (pressure sore on the big toe occurred in over 800 training sessions.Home-based robotic locomotion training with MoreGait is feasible and safe. The magnitude of functional improvements achieved by MoreGait in individuals with iSCI is well within the range of complex locomotion robots used in hospitals. Thus, unsupervised MoreGait training potentially represents an option to prolong effective training aiming at recovery of locomotor function beyond in-patient rehabilitation

  9. 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.

  10. Silica dust exposure: Effect of filter size to compliance determination

    Science.gov (United States)

    Amran, Suhaily; Latif, Mohd Talib; Khan, Md Firoz; Leman, Abdul Mutalib; Goh, Eric; Jaafar, Shoffian Amin

    2016-11-01

    Monitoring of respirable dust was performed using a set of integrated sampling system consisting of sampling pump attached with filter media and separating device such as cyclone or special cassette. Based on selected method, filter sizes are either 25 mm or 37 mm poly vinyl chloride (PVC) filter. The aim of this study was to compare performance of two types of filter during personal respirable dust sampling for silica dust under field condition. The comparison strategy focused on the final compliance judgment based on both dataset. Eight hour parallel sampling of personal respirable dust exposure was performed among 30 crusher operators at six quarries. Each crusher operator was attached with parallel set of integrated sampling train containing either 25 mm or 37 mm PVC filter. Each set consisted of standard flow SKC sampler, attached with SKC GS3 cyclone and 2 pieces cassette loaded with 5.0 µm of PVC filter. Samples were analyzed by gravimetric technique. Personal respirable dust exposure between the two types of filters indicated significant positive correlation (p arithmetic mean(AM) and geometric mean(GM). In overall we concluded that personal respirable dust exposure either based on 25mm or 37mm PVC filter will give similar compliance determination. Both filters are reliable to be used in respirable dust monitoring for silica dust related exposure.

  11. Fluxoid formation: size effects and non-equilibrium universality

    Energy Technology Data Exchange (ETDEWEB)

    Weir, David J; Rivers, Ray J, E-mail: david.weir03@imperial.ac.uk, E-mail: r.rivers@imperial.ac.uk [Blackett Laboratory, Imperial College London SW7 2AZ (United Kingdom)

    2011-03-01

    Simple causal arguments put forward by Kibble and Zurek suggest that the scaling behaviour of condensed matter at continuous transitions is related to the familiar universality classes of the systems at quasi-equilibrium. Although proposed 25 years ago or more, it is only in the last few years that it has been possible to devise experiments from which scaling exponents can be determined and in which this scenario can be tested. In Ref. [1], an unusually high Kibble-Zurek scaling exponent was reported for spontaneous fluxoid production in a single isolated superconducting Nb loop, albeit with low density. Using analytic approximations backed up by Langevin simulations, we argue that densities as small as these are too low to be attributable to scaling, and are conditioned by the small size of the loop. We also reflect on the physical differences between slow quenches and small rings, and derive some criteria for these differences, noting that recent work on slow quenches does not adequately explain the anomalous behaviour seen here.

  12. Effects of size, fixation location, and inversion on face identification

    National Research Council Canada - National Science Library

    Sekuler, Allison; Pachai, Matthew; Hashemi, Ali; Bennett, Patrick

    2015-01-01

    One possible explanation for the face inversion effect (FIE) is that inversion swaps the eye and mouth locations relative to fixation, and attention typically is directed to the top of a stimulus for faces...

  13. Probabilistic size effect law for mode II fracture of critical lengths in snow slab weak layers

    Science.gov (United States)

    McClung, David

    2016-04-01

    Snow slab avalanches initiate by mode II fracture within relatively thin weak layers under stronger, cohesive slabs. For risk based avalanche prediction, it is important to understand the fracture properties of alpine snow. Alpine snow is a quasi-brittle material with a size effect on nominal shear strength meaning that strength decreases with increasing sample size. A related size effect is the critical length required for rapid propagation of a shear fracture. In that case, the probability of fracture increases with increasing crack length. In this paper, 45 sets of field measured critical lengths are presented based on 591 individual tests. From analysis, a probabilistic size effect law is derived analogous to the deterministic size effect law for nominal shear strength related to fracture mechanics. It is shown that in the limit of small crack length, the plastic limit is approached with a very low probability of failure implying very high shear strength. At the other limit, for long enough cracks, the limit of Linear Elastic Fracture Mechanics (LEFM) is approached implying high probability of failure and low nominal shear strength compatible with large sample size. It is shown that the strength size effect law and the critical length size effect law form a duality for analysis of snow avalanche weak layers. It is expected the critical length size effect law will be important in applications.

  14. Effect of grain size on the domain structures and electromechanical responses of ferroelectric polycrystal

    Science.gov (United States)

    Li, Xinkai; Wang, Jie

    2017-01-01

    The effect of grain size on the domain structures and electromechanical responses of ferroelectric polycrystals is investigated by a phase field model. The phase field simulations show that the different types of domains in different size of grains play an important role in the size-dependent properties of ferroelectric polycrystals. It is found that the remnant polarization, coercive field and dielectric coefficient increase monotonously with the increase of grain size. However, the piezoelectric coefficient increases first and then decreases as the grain size increases. The decrease of vortex domains is responsible for the increase of piezoelectric coefficient in the range of small grain size, the decrease of 90° domain walls results in the decrease of piezoelectric coefficient in the range of large grain size. In addition, different domain structures in different size of grains have also great influence on the mechanical depolarization of the ferroelectric polycrystals subjected to a compressive stress.

  15. Design of Pre-post Training and Testing System for Coal Miner%煤矿入井人员岗前培训考试系统的设计

    Institute of Scientific and Technical Information of China (English)

    贺耀宜

    2012-01-01

    针对煤矿现有入井人员考勤系统与安全培训系统相互独立、安全培训效果差的问题,提出了一种煤矿入井人员岗前培训考试系统的设计方案,给出了系统组成、工作流程及主要功能.该系统采用B/S、C/S混合模式开发,以统一门户管理方式与安全量化管理系统和虹膜考勤系统有机集成,并采用先考试后考勤的人员入井管理方式,即只有通过考试的人员才可下井.实际应用表明,该系统提高了煤矿企业职工学习安全知识的主动性和煤矿安全培训的有效性,为煤矿安全管理培训提供了一种新的思路与方法.%In order to solve problems that existing safety training system of coal mine is independent of welling attendance system and has poor training effect, the paper proposed a design scheme of pre-post training and testing system for coal miner, and gave structure, working process and main functions of the system. The system uses mixed development mode of B/S and C/S, integrates safety quantification management system and iris attendance system through unified portal management mode, and adopts welling management method of examination before attendance, namely the miners only passing examination can go underground. The application showed that the system improves initiative of miners for learning safety rules and validity of safety training of coal mine, which provides a new method of safety management and training of coal mine.

  16. 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.

  17. 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

  18. Electrochemiluminescent metallopolymer-nanoparticle composites: nanoparticle size effects.

    Science.gov (United States)

    Devadoss, Anitha; Dickinson, Calum; Keyes, Tia E; Forster, Robert J

    2011-03-15

    Metallopolymer-gold nanocomposites have been synthesized in which the metal complex-Au nanoparticle (NP) mole ratio is systematically varied by mixing solutions of 4-(dimethylamino) pyridine protected gold nanoparticles and a [Ru(bpy)(2)PVP(10)](2+) metallopolymer; bpy is 2,2'-bipyridyl and PVP is poly-(4-vinylpyridine). The impact of changing the gold nanoparticle diameter ranging from 4.0 ± 0.5 to 12.5 ± 1 nm has been investigated. The photo induced emission of the metallopolymer undergoes static quenching by the metal nanoparticles irrespective of their size. When the volume ratio of Au NP-Ru is 1, the quenching efficiency increases from 38% to 93% on going from 4.0 ± 0.5 to 12.5 ± 1 nm diameter nanoparticles while the radius of the quenching sphere remains unaffected at 75 ± 5 Å. The conductivity of thin films is initially unaffected by nanoparticle incorporation until a percolation threshold is reached at a mole ratio of 4.95 × 10(-2) after which the conductivity increases before reaching a maximum. For thin films of the nanocomposites on electrodes, the electrochemiluminescence intensity of the nanocomposite initially increases as nanoparticles are added before decreasing for the highest loadings. The electrochemiluminescence intensity increases with increasing nanoparticle diameter. The electrochemiluminescence (ECL) emission intensity of the nanocomposite formed using 12.5 nm particles at mole ratios between 5 × 10(-3) and 10 × 10(-3) is approximately 7-fold higher than that found for the parent metallopolymer. The application of these materials for low cost ECL-based point of care devices is discussed.

  19. Sensitivity analysis of size effect on the performance of hydrostatic bearing

    Directory of Open Access Journals (Sweden)

    Dongju Chen

    2016-01-01

    Full Text Available For size effect on solid-liquid interface of hydrostatic bearing oil film gap flow in two-dimension, fluid dynamic method is applied to investigate the influence of size effect on bearing capacity, dynamic stiffness and other performances. With the consideration of size effect, Reynolds equation is modified by adopting velocity slip boundary condition into Reynolds equation. The sensitivity factors are used to make a quantitative and qualitative analysis. Numerical simulation results show that size effect will affect bearing performances to a certain degree and the effect curve of size effect on bearing performances are given. The four maximum oil film pressures reduce with the increase of slip length. The maximum sensitivity of bearing capacity is 81.94%.

  20. Particle size effects in Fischer-Tropsch synthesis by Co catalyst supported on carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Ali Nakhaei Pour; Elham Hosaini; Mohammad Izadyar; Mohammad Reza Housaindokht

    2015-01-01

    The effect of Co particle size on the Fischer-Tropsch synthesis (FTS) activity of carbon nanotube (CNT)-supported Co catalysts was investigated. Microemulsion (using water-to-surfactant molar ratios of 2 to12) and impregnation techniques were used to prepare catalysts with different Co particle sizes. Kinetic studies were performed to understand the effect of Co particle size on catalytic activity. Size-dependent kinetic parameters were developed using a thermodynamic method, to evaluate the structural sensitivity of the CNT-supported Co catalysts. The size-independent FTS reaction rate constant and size-independent adsorption parameter increased with increasing reac-tion temperature. The Polani parameter also depended on catalyst particle size, because of changes in the catalyst surface coverage.

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

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2015-01-01

    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...... 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...... that the energetic length parameter has negligible effect on the rolling quantities of interest, while the contribution coming from the dissipative length parameter can be dominant. Considering a slow and a fast moving sheet, respectively, convergence towards the rate independent limit is demonstrated...

  2. Finite size effects in stimulated laser pair production

    CERN Document Server

    Heinzl, Thomas; Marklund, Mattias

    2010-01-01

    We consider stimulated pair production in a strong laser background, using the language of lightcone field theory. In an infinite plane wave, we show that the lightcone momentum transfer to the pair must be a multiple of the laser frequency, which results in the usual interpretation of multi-photon production of pairs with an effective mass. In a pulse, the momentum transfer is continuous, exhibiting resonant behaviour for effective mass pair production. We show that this is completely analogous to a diffraction process, and that the fine structure of the emission rate is that of a diffraction pattern resulting from interference of the produced pairs' wavefunctions.

  3. Material nanosizing effect on living organisms: non-specific, biointeractive, physical size effects

    Science.gov (United States)

    Watari, Fumio; Takashi, Noriyuki; Yokoyama, Atsuro; Uo, Motohiro; Akasaka, Tsukasa; Sato, Yoshinori; Abe, Shigeaki; Totsuka, Yasunori; Tohji, Kazuyuki

    2009-01-01

    Nanosizing effects of materials on biological organisms was investigated by biochemical cell functional tests, cell proliferation and animal implantation testing. The increase in specific surface area causes the enhancement of ionic dissolution and serious toxicity for soluble, stimulative materials. This effect originates solely from materials and enhances the same functions as those in a macroscopic size as a catalyst. There are other effects that become prominent, especially for non-soluble, biocompatible materials such as Ti. Particle size dependence showed the critical size for the transition of behaviour is at approximately 100 μm, 10 μm and 200 nm. This effect has its origin in the biological interaction process between both particles and cells/tissue. Expression of superoxide anions, cytokines tumour necrosis factor-α and interleukin-1β from neutrophils was increased with the decrease in particle size and especially pronounced below 10 μm, inducing phagocytosis to cells and inflammation of tissue, although inductively coupled plasma chemical analysis showed no dissolution from Ti particles. Below 200 nm, stimulus decreases, then particles invade into the internal body through the respiratory or digestive systems and diffuse inside the body. Although macroscopic hydroxyapatite, which exhibits excellent osteoconductivity, is not replaced with natural bone, nanoapatite composites induce both phagocytosis of composites by osteoclasts and new bone formation by osteoblasts when implanted in bone defects. The progress of this bioreaction results in the conversion of functions to bone substitution. Although macroscopic graphite is non-cell adhesive, carbon nanotubes (CNTs) are cell adhesive. The adsorption of proteins and nano-meshwork structure contribute to the excellent cell adhesion and growth on CNTs. Non-actuation of the immune system except for a few innate immunity processes gives the non-specific nature to the particle bioreaction and

  4. Predator size - prey size relationships of marine fish predators: interspecific variation and effects of ontogeny and body size on trophic-niche breadth

    National Research Council Canada - National Science Library

    Frederick S. Scharf; Francis Juanes; Rodney A. Rountree

    2000-01-01

    We utilized a long-term data base collected over a broad geographic range to examine predator size - prey size relationships for 18 species of marine fish predators from continental shelf waters off...

  5. Aerodynamic ground effect in fruitfly sized insect takeoff

    CERN Document Server

    Kolomenskiy, Dmitry; Engels, Thomas; Liu, Hao; Schneider, Kai; Nave, Jean-Christophe

    2015-01-01

    Flapping-wing takeoff is studied using numerical modelling, considering the voluntary takeoff of a fruitfly as reference. The parameters of the model are then varied to explore the possible effects of interaction between the flapping-wing model and the ground plane. The numerical method is based on a three-dimensional Navier-Stokes solver and a simple flight dynamics solver that accounts for the body weight, inertia, and the leg thrust. Forces, power and displacements are compared for takeoffs with and without ground effect. Natural voluntary takeoff of a fruitfly, modified takeoffs and hovering are analyzed. The results show that the ground effect during the natural voluntary takeoff is negligible. In the modified takeoffs, the ground effect does not produce any significant increase of the vertical force neither. Moreover, the vertical force even drops in most of the cases considered. There is a consistent increase of the horizontal force, and a decrease of the aerodynamic power, if the rate of climb is suff...

  6. Little effect of climate change on body size of herbivorous beetles.

    Science.gov (United States)

    Baar, Yuval; Friedman, Ariel Leib Leonid; Meiri, Shai; Scharf, Inon

    2016-11-07

    Ongoing climate change affects various aspects of an animal's life, with important effects on distribution range and phenology. The relationship between global warming and body size changes in mammals and birds has been widely studied, with most findings indicating a decline in body size over time. Nevertheless, little data exist on similar size change patterns of invertebrates in general and insects in particular, and it is unclear whether insects should decrease in size or not with climate warming. We measured over 4000 beetle specimens, belonging to 29 beetle species in 8 families, collected in Israel during the last 100 years. The sampled species are all herbivorous. We examined whether beetle body size had changed over the years, while also investigating the relationships between body size and annual temperature, precipitation, net primary productivity (NPP) at the collection site and collection month. None of the environmental variables, including the collection year, was correlated with the size of most of the studied beetle species, while there were strong interactions of all variables with species. Our results, though mostly negative, suggest that the effect of climate change on insect body size is species-specific and by no means a general macro-ecological rule. They also suggest that the intrapopulation variance in body size of insects collected as adults in the field is large enough to conceal intersite environmental effects on body size, such as the effect of temperature and NPP.

  7. Estimation of Effect Size from a Series of Experiments Involving Paired Comparisons.

    Science.gov (United States)

    Gibbons, Robert D.; And Others

    1993-01-01

    A distribution theory is derived for a G. V. Glass-type (1976) estimator of effect size from studies involving paired comparisons. The possibility of combining effect sizes from studies involving a mixture of related and unrelated samples is also explored. Resulting estimates are illustrated using data from previous psychiatric research. (SLD)

  8. Majority, Minority, and Parity: Effects of Gender and Group Size on Perceived Group Variability

    Science.gov (United States)

    Voci, Alberto; Hewstone, Miles; Crisp, Richard J.; Rubin, Mark

    2008-01-01

    We investigated the effects of gender and group size on perceptions of group variability, using groups of students taking different majors that varied in the proportion of men and women (female-majority, parity, and male-majority). We found that both group size and gender had consistent effects on perceived out-group variability, even when…

  9. Standardized Regression Coefficients as Indices of Effect Sizes in Meta-Analysis

    Science.gov (United States)

    Kim, Rae Seon

    2011-01-01

    When conducting a meta-analysis, it is common to find many collected studies that report regression analyses, because multiple regression analysis is widely used in many fields. Meta-analysis uses effect sizes drawn from individual studies as a means of synthesizing a collection of results. However, indices of effect size from regression analyses…

  10. On the origin of the cobalt particle size effects in Fischer−Tropsch catalysis

    NARCIS (Netherlands)

    den Breejen, J.P.; Radstake, P.B.; Bezemer, G.L.; Bitter, J.H.; Froseth, V.; Holmen, A.; de Jong, K.P.

    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)

  11. Graphical Methods for Assessing Effect Size: Some Alternatives to Cohen's d

    Science.gov (United States)

    Wilcox, Rand R.

    2006-01-01

    Reporting effect size plays an integral role in educational and psychological research and is required by many journals. Certainly, the best-known measure of effect size is Cohen's d, which represents a substantial improvement over using p values. But Cohen's d is known to suffer from some fundamental concerns. The author's goal was to illustrate…

  12. A Visitor's Guide to Effect Sizes--Statistical Significance versus Practical (Clinical) Importance of Research Findings

    Science.gov (United States)

    Hojat, Mohammadreza; Xu, Gang

    2004-01-01

    Effect Sizes (ES) are an increasingly important index used to quantify the degree of practical significance of study results. This paper gives an introduction to the computation and interpretation of effect sizes from the perspective of the consumer of the research literature. The key points made are: (1) "ES" is a useful indicator of the…

  13. Effects of Class Size and Adaptive Teaching Competency on Classroom Processes and Academic Outcome

    Science.gov (United States)

    Bruhwiler, Christian; Blatchford, Peter

    2011-01-01

    In many studies of class size effects, teacher characteristics are missing, even though many argue it is not class size that is important but teacher quality. In the present study teachers' effectiveness on the learning progress was assessed while teaching a unit with predefined learning objectives. To measure adaptive teaching competency a…

  14. Size effect study in magnetoelectric BiFeO3 system

    Indian Academy of Sciences (India)

    Shwetha Shetty; V R Palkar; R Pinto

    2002-05-01

    In this paper, we report for the first time finite size effects on Néel temperature (N) of magnetoelectric BiFeO3 system. Novel wet chemical route has been developed to produce fine particles of BiFeO3 with controlled size and size distribution. Unlike other oxide systems, lattice volume contraction has been observed with decrease in particle size. The decrease in N is co-related to unit cell volume contraction occurring with reduction in particle size.

  15. A finite-element approach to evaluating the size effects of complex nanostructures

    Science.gov (United States)

    Lu, Dingjie; Xie, Yi Min; Li, Qing; Huang, Xiaodong; Li, Yang Fan; Zhou, Shiwei

    2016-12-01

    The size effects that reveal the dramatic changes of mechanical behaviour at nanoscales have traditionally been analysed for regular beam systems. Here, the method of using finite-element analysis is explored with the intention of evaluating the size effects for complex nanostructures. The surface elasticity theory and generalized Young-Laplace equation are integrated into a beam element to account for the size effects in classical Euler-Bernoulli and Timoshenko beam theories. Computational results match well with the theoretical predictions on the size effect for a cantilever beam and a cubic unit cell containing 24 horizontal/vertical ligaments. For a simply supported nanowire, it is found that the results are very close to the experimental data. With the assumption that nanoporous gold is composed of many randomly connected beams, for the first time, the size effect of such a complex structure is numerically determined.

  16. Size effect in composite materials and structures: Basic concepts and design considerations

    Science.gov (United States)

    Zweben, Carl

    1994-01-01

    Composite materials display strength characteristics that are similar to those of brittle ceramics, whose strengths are known to decrease with increasing volume for a uniform state of stress (size effect) and also are dependent on stress distribution. These similarities raise the question of whether there is also a size effect in composite materials and structures. There is significant, but inconclusive experimental evidence for the existence of a size effect in composites. Macroscopic and micromechanical statistical models have been developed which predict a size effect and are in general agreement with experimental data. The existence of a significant size effect in composites would be of great importance. For example, it would mean that use of standard test coupons to establish design allowables for large structures could be very nonconservative. Further, it would be necessary to analyze the strength of large composite structures using statistical methods, as is done for ceramics.

  17. Sample size calculation in cost-effectiveness cluster randomized trials: optimal and maximin approaches.

    Science.gov (United States)

    Manju, Md Abu; Candel, Math J J M; Berger, Martijn P F

    2014-07-10

    In this paper, the optimal sample sizes at the cluster and person levels for each of two treatment arms are obtained for cluster randomized trials where the cost-effectiveness of treatments on a continuous scale is studied. The optimal sample sizes maximize the efficiency or power for a given budget or minimize the budget for a given efficiency or power. Optimal sample sizes require information on the intra-cluster correlations (ICCs) for effects and costs, the correlations between costs and effects at individual and cluster levels, the ratio of the variance of effects translated into costs to the variance of the costs (the variance ratio), sampling and measuring costs, and the budget. When planning, a study information on the model parameters usually is not available. To overcome this local optimality problem, the current paper also presents maximin sample sizes. The maximin sample sizes turn out to be rather robust against misspecifying the correlation between costs and effects at the cluster and individual levels but may lose much efficiency when misspecifying the variance ratio. The robustness of the maximin sample sizes against misspecifying the ICCs depends on the variance ratio. The maximin sample sizes are robust under misspecification of the ICC for costs for realistic values of the variance ratio greater than one but not robust under misspecification of the ICC for effects. Finally, we show how to calculate optimal or maximin sample sizes that yield sufficient power for a test on the cost-effectiveness of an intervention.

  18. 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.

  19. 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...... an increased growth rate due to the stress concentrations around the larger voids and a reduced growth rate due to the nonlocal effects is studied. The analyses are based on an axisymmetric unit cell model with special boundary conditions, which allow for a relatively simple investigation of a full three...

  20. Effects of Magnet Size and Geometry on Magnetic Levitation Force

    Institute of Scientific and Technical Information of China (English)

    M. K. Alqadi; H. M. Al-khateeb; F. Y. Alzoubi; N. Y. Ayoub

    2007-01-01

    We obtain analytical relations for the levitation force as a function of dimensions of the superconductor-magnet system. The force has been calculated on the basis of the dipole-dipole interaction model.The effect of thickness of the superconductor on the levitation force is investigated. The results show that the influence of geometry and thickness of the magnet becomes significantly large at small levitation distances. Furthermore, approximating the permanent magnet as a point dipole results in an inaccurate estimation of the levitation force.

  1. Effect of the Size Distribution of Nanoscale Dispersed Particles on the Zener Drag Pressure

    Science.gov (United States)

    Eivani, A. R.; Valipour, S.; Ahmed, H.; Zhou, J.; Duszczyk, J.

    2011-04-01

    In this article, a new relationship for the calculation of the Zener drag pressure is described in which the effect of the size distribution of nanoscale dispersed particles is taken into account, in addition to particle radius and volume fraction, which have been incorporated in the existing relationships. Microstructural observations indicated a clear correlation between the size distribution of dispersed particles and recrystallized grain sizes in the AA7020 aluminum alloy. However, the existing relationship to calculate the Zener drag pressure yielded a negligible difference of 0.016 pct between the two structures homogenized at different conditions resulting in totally different size distributions of nanoscale dispersed particles and, consequently, recrystallized grain sizes. The difference in the Zener drag pressure calculated by the application of the new relationship was 5.1 pct, being in line with the experimental observations of the recrystallized grain sizes. Mathematical investigations showed that the ratio of the Zener drag pressure from the new equation to that from the existing equation is maximized when the number densities of all the particles with different sizes are equal. This finding indicates that in the two structures with identical parameters except the size distribution of nanoscale dispersed particles, the one that possesses a broader size distribution of particles, i.e., the number densities of particles with different sizes being equal, gives rise to a larger Zener drag pressure than that having a narrow size distribution of nanoscale dispersed particles, i.e., most of the particles being in the same size range.

  2. Debonding failure and size effects in micro reinforced composites

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang; Niordson, Christian Frithiof

    2010-01-01

    Failure in micro-reinforced composites is investigated numerically using the strain-gradient plasticity theory of Gudmundson [Gudmundson, P., 2004. A unified treatment of strain gradient plasticity. Journal of the Mechanics and Physics of Solids 52 (6) 1379–1406] in a plane strain visco......-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...

  3. GENEALOGICAL DECOMPOSITION OF THE EFFECTIVE POPULATION SIZE: A CASE STUDY ON CROATIAN AUTOCHTHONOUS CATTLE BREEDS

    Directory of Open Access Journals (Sweden)

    Martin Reljanović

    2015-09-01

    Full Text Available Effective population size (Ne is one of the most important tools used to assess genetic diversity for conservation purposes. Using pedigree data of three Croatian autochthonous cattle breeds (Buša, Istrian and Slavonian Syrmian Podolian the effective maternal (NeF, paternal (NeM and combined maternal-paternal (NeFM population size was estimated. Additionally, we estimated the effective population size based on the census population sex ratio (Nes, the effective population size from the individual increase in inbreeding (NeFi and the effective population size from individual increase in coancestry (NeCi. We compared these sizes with the values obtained for 20 additional cattle populations, as well as with the newly calculated NeFM. The effective population sizes calculated for three autochthonous breeds were consistently the lowest in amongst all the considered cattle breeds. Utilisation of extremely small numbers of breeding males is the main reason for the observed reduction in the effective population size. The decomposition of effective population size into maternal and paternal components is shown to be an informative parameter in detecting the reduction of the effective population size as a consequence of unequal sex contribution. Still, the impact of the pedigree depth and completeness on the NeF, NeM and NeFM estimation remain to be analysed. A large deviation between Nes and all other methods of Ne estimation was observed and it is our recommendation that breeders and stakeholders should consider using alternative methods of Ne estimation when planning breeding programmes as well as in the determination of the endangered status of animal populations.

  4. Probing finite size effects in $(\\lambda \\Phi^{4})_4$ MonteCarlo calculations

    CERN Document Server

    Agodi, A

    1999-01-01

    The Constrained Effective Potential (CEP) is known to be equivalent to the usual Effective Potential (EP) in the infinite volume limit. We have carried out MonteCarlo calculations based on the two different definitions to get informations on finite size effects. We also compared these calculations with those based on an Improved CEP (ICEP) which takes into account the finite size of the lattice. It turns out that ICEP actually reduces the finite size effects which are more visible near the vanishing of the external source.

  5. The void-size effect on plastic flow localization in the Gurson model

    Science.gov (United States)

    Jie, Wen; Yonggang, Huang; Keh-Chih, Hwang

    2004-08-01

    Recent studies have shown that the size of microvoids has a significant effect on the void growth rate. The purpose of this paper is to explore whether the void size effect can influence the plastic flow localization in ductile materials. We have used the extended Gurson's dilatational plasticity theory, which accounts for the void size effect, to study the plastic flow localization in porous solids with long cylindrical voids. The localization model of Rice is adopted, in which the material inside the band may display a different response from that outside the band at the incipient plastic flow localization. The present study shows that it has little effect on the shear band angle.

  6. THE VOID-SIZE EFFECT ON PLASTIC FLOW LOCALIZATION IN THE GURSON MODEL

    Institute of Scientific and Technical Information of China (English)

    WEN Jie; HUANG Yonggang; HWANG Keh-Chih

    2004-01-01

    Recent studies have shown that the size of microvoids has a significant effect on the void growth rate. The purpose of this paper is to explore whether the void size effect can influence the plastic flow localization in ductile materials. We have used the extended Gurson's dilatational plasticity theory, which accounts for the void size effect, to study the plastic flow localization in porous solids with long cylindrical voids. The localization model of Rice is adopted, in which the material inside the band may display a different response from that outside the band at the incipient plastic flow localization. The present study shows that it has little effect on the shear band angle.

  7. Coupling effects of void size and void shape on the growth of prolate ellipsoidal microvoid

    Institute of Scientific and Technical Information of China (English)

    Minsheng Huang; Zhenhuan Li; Cheng Wang

    2005-01-01

    The combined effects of void size and void shape on the void growth are studied by using the classical spectrum method. An infinite solid containing an isolated prolate spheroidal void is considered to depict the void shape effect and the Fleck-Hutchinson phenomenological strain gradient plasticity theory is employed to capture the size effects. It is found that the combined effects of void size and void shape are mainly controlled by the remote stress triaxiality. Based on this, a new size-dependent void growth model similar to the Rice-Tracey model is proposed and an important conclusion about the size-dependent void growth is drawn: the growth rate of the void with radius smaller than a critical radius rc may be ignored. It is interesting that rc is a material constant independent of the initial void shape and the remote stress triaxiality.

  8. 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.

  9. Calculated Grain Size-Dependent Vacancy Supersaturation and its Effect on Void Formation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Foreman, A. J. E.

    1974-01-01

    In order to study the effect of grain size on void formation during high-energy electron irradiations, the steady-state point defect concentration and vacancy supersaturation profiles have been calculated for three-dimensional spherical grains up to three microns in size. In the calculations...... of vacancy supersaturation as a function of grain size, the effects of internal sink density and the dislocation preference for interstitial attraction have been included. The computations show that the level of vacancy supersaturation achieved in a grain decreases with decreasing grain size. The grain size...... dependence of the maximum vacancy supersaturation in the centre of the grains is found to be very similar to the grain size dependence of the maximum void number density and void volume swelling measured in the central regions of austenitic stainless steel grains. This agreement reinforces the interpretation...

  10. How Much Do Metamemory Beliefs Contribute to the Font-Size Effect in Judgments of Learning?

    Directory of Open Access Journals (Sweden)

    Xiao Hu

    Full Text Available Evidence shows that the font size of study items significantly influences judgments of learning (JOLs and that people's JOLs are generally higher for larger words than for smaller words. Previous studies have suggested that font size influences JOLs in a belief-based way. However, few studies have directly examined how much people's beliefs contribute to the font-size effect in JOLs. This study investigated the degree to which font size influenced JOLs in a belief-based way. In Experiment 1, one group of participants (learners studied words with different font sizes and made JOLs, whereas another group of participants (observers viewed the learners' study phase and made JOLs for the learners. In Experiment 2, participants made both JOLs and belief-based recall predictions for large and small words. Our results suggest that metamemory beliefs play an important role in the font-size effect in JOLs.

  11. 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.

  12. Size-dependent axisymmetric vibration of functionally graded circular plates in bifurcation/limit point instability

    Science.gov (United States)

    Ashoori, A. R.; Vanini, S. A. Sadough; Salari, E.

    2017-04-01

    In the present paper, vibration behavior of size-dependent functionally graded (FG) circular microplates subjected to thermal loading are carried out in pre/post-buckling of bifurcation/limit-load instability for the first time. Two kinds of frequently used thermal loading, i.e., uniform temperature rise and heat conduction across the thickness direction are considered. Thermo-mechanical material properties of FG plate are supposed to vary smoothly and continuously throughout the thickness based on power law model. Modified couple stress theory is exploited to describe the size dependency of microplate. The nonlinear governing equations of motion and associated boundary conditions are extracted through generalized form of Hamilton's principle and von-Karman geometric nonlinearity for the vibration analysis of circular FG plates including size effects. Ritz finite element method is then employed to construct the matrix representation of governing equations which are solved by two different strategies including Newton-Raphson scheme and cylindrical arc-length method. Moreover, in the following a parametric study is accompanied to examine the effects of the several parameters such as material length scale parameter, temperature distributions, type of buckling, thickness to radius ratio, boundary conditions and power law index on the dimensionless frequency of post-buckled/snapped size-dependent FG plates in detail. It is found that the material length scale parameter and thermal loading have a significant effect on vibration characteristics of size-dependent circular FG plates.

  13. Numerical distance and size effects dissociate in Indo-Arabic number comparison.

    Science.gov (United States)

    Krajcsi, Attila

    2017-06-01

    Numerical distance and size effects (easier number comparisons with large distance or small size) are mostly supposed to reflect a single effect, the ratio effect, which is a consequence of activation of the analog number system (ANS), working according to Weber's law. In an alternative model, symbolic numbers can be processed by a discrete semantic system (DSS), in which the distance and size effects could originate in two independent factors: the distance effect depending on the semantic distance of the units, and the size effect depending on the frequency of the symbols. Whereas in the classic view both symbolic and nonsymbolic numbers are processed by the ANS, in the alternative view only nonsymbolic numbers are processed by the ANS, but symbolic numbers are handled by the DSS. The present work contrasts the two views, investigating whether the sizes of the distance and size effects correlate in nonsymbolic dot comparison and in symbolic Indo-Arabic comparison tasks. If a comparison is backed by the ANS, the distance and size effects should correlate, because the two effects are merely two ways to measure the same ratio effect. However, if a comparison is supported by another system-for example, the DSS-the two effects might dissociate. In the present measurements, the distance and size effects correlated very strongly in the dot comparison task, but they did not correlate in the Indo-Arabic comparison task. Additionally, the effects did not correlate between the Indo-Arabic and dot comparison tasks. These results suggest that symbolic number comparison is not handled by the ANS, but by an alternative representation, such as the DSS.

  14. Effect of grain size on the elastic properties of nanocrystalline {alpha}-iron

    Energy Technology Data Exchange (ETDEWEB)

    Latapie, A.; Farkas, D

    2003-03-03

    The effect of grain size on the elastic properties of nanocrystalline {alpha}-iron is reported using atomistic simulations. A softening of the elastic properties is observed for grain sizes ranging from 12 nm down to 6 nm. The decrease in the Young's and shear moduli with decreasing grain size is in agreement with experimental data and matches an analytical model based on the rule of mixtures for composite materials.

  15. Effect of the size distribution of nanoscale dispersed particles on the Zener drag pressure

    OpenAIRE

    Eivani, A.R.; Valipour, S.; Ahmed, H.; Zhou, J; Duszczyk, J.

    2010-01-01

    In this article, a new relationship for the calculation of the Zener drag pressure is described in which the effect of the size distribution of nanoscale dispersed particles is taken into account, in addition to particle radius and volume fraction, which have been incorporated in the existing relationships. Microstructural observations indicated a clear correlation between the size distribution of dispersed particles and recrystallized grain sizes in the AA7020 aluminum alloy. However, the ex...

  16. Day-of-the-week and Size Effects in Emerging Markets: Evidence From Chile Day-of-the-week and Size Effects in Emerging Markets: Evidence From Chile

    Directory of Open Access Journals (Sweden)

    Eduardo Walker

    2000-03-01

    Full Text Available This paper studies empirical regularities of daily log returns for the years 1989 through 1996, using aggregate indexes and quintiles rated by size, for a specific emerging market: the case of Chile. Within the context of the existing literature on emerging markets, this study's contributions are the following: First, earlier studies use aggregate indexes. This one extends the samples and also considers more detailed information, which gives a better representation of individual stock behavior. Second, non-parametric statistical tests are used as a complements of classical ones. The study's main result shows important day-of-the-week effects on average returns and traded volumes, but not on variances. These results, obtained with both classical and non-parametric methods, are valid for aggregate indexes, quintiles and sub-periods. We also find a seasonal pattern in the size-effect, which it is significantly positive on Fridays and significantly negative on Mondays. In the case of this emerging market, the evidence is inconsistent with the hypothesis that the weekend effect is due to small-investor-portfolio-adjustment-on-Mondays. Unless there is a reason to believe that bad news is put off to the weekend (and good news to Fridays especially in the case of smaller firms, the seasonal size-effect and the absence of effects in variances also contradict this hypothesis. There is stronger evidence that favors the hypothesis that investors comply with weekly investment plans, as proposed herein. Other results confirm that daily returns in the Chilean stock market behave very much like the more developed countries', although the different effects (size-, kurtosis and autocorrelation are more pronounced. This is also true for the size-based quintiles. Results are also consistent with those obtained by other authors that analyze emerging market monthly index returns. This paper studies empirical regularities of daily log returns for the years 1989

  17. The facilitative effect of transcranial direct current stimulation on visuospatial working memory in patients with diabetic polyneuropathy: a pre-post sham-controlled study

    Directory of Open Access Journals (Sweden)

    YI-JEN WU

    2016-09-01

    Full Text Available Diabetes mellitus (DM can lead to diabetic polyneuropathy (DPN and cognitive deficits that manifest as peripheral and central neuropathy, respectively. In this study we investigated the relationship between visuospatial working memory (VSWM capacity and DPN severity, and attempted to improve VSWM in DPN patients via the use of transcranial direct current stimulation (tDCS. Sixteen DPN patients and sixteen age- and education-matched healthy control subjects received Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV and Montreal Cognitive Assessment (MOCA for baseline cognitive assessment. A forward- and backward-recall computerized Corsi block tapping task (CBT, both with and without a concurrent motor interference task was used to measure VSWM capacity. Each DPN patient underwent a pre-treatment CBT, followed by tDCS or sham treatment, then a post-treatment CBT on two separate days. We found that although patients with severe DPN (Dyck’s grade 2a or 2b showed comparable general intelligence scores on WAIS-IV as their age- and education-matched healthy counterparts, they nonetheless showed mild cognitive impairment on MOCA and working memory deficit on digit-span test of WAIS-IV. Furthermore, patients’ peripheral nerve conduction velocity (NCV was positively correlated with their VSWM span in the most difficult CBT condition that involved backward-recall with motor interference such that patients with worse NCV also had lower VSWM span. Most importantly, anodal tDCS over the right DLPFC was able to improve low-performing patients’ VSWM span to be on par with the high-performers, thereby eliminating the correlation between NCV and VSWM. In summary, these findings suggest that 1 mild cognitive impairment and severe peripheral neuropathy can coexist with unequal severity in diabetic patients, 2 the positive correlation of VSWM and NCV suggests a link between peripheral and central neuropathies and 3 anodal tDCS over the right DLPFC can improve DPN patients’ VSWM, particularly for the low-performing patients.

  18. Effect of Pre/Post T6 Heat Treatment on the Mechanical Properties of Laser Welded SSM Cast A356 Aluminium Alloy

    CSIR Research Space (South Africa)

    Akhter, R

    2007-02-01

    Full Text Available a weld seams h acceptable properties. R. Akhter et al. / Materials Science and Engineering A 447 (2007) 192–196 193 wit centre-to-centr Th condition ejectio configurations an g durin t c hig plasma rate othe h he pool... prone to plasma formation and because it is much avier than helium it transfers more momentum to the weld . In the case of aluminium the weld metal has low viscosity d is easily disturbed. We believed that a mixture of helium d argon would strike...

  19. Poster — Thur Eve — 51: An analysis of the effectiveness of automated pre-, post- and intra-treatment auditing of electronic health records

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, A.; Seuntjens, J.; Parker, W.; Kildea, J. [Dept. of Medical Physics, McGill University Health Centre, Montreal, QC (Canada); Freeman, C. [Dept. of Radiation Oncology, McGill University Health Centre, Montreal, QC (Canada)

    2014-08-15

    We describe development of automated, web-based, electronic health record (EHR) auditing software for use within our paperless radiation oncology clinic. By facilitating access to multiple databases within the clinic, each patient's EHR is audited prior to treatment, regularly during treatment, and post treatment. Anomalies such as missing documentation, non-compliant workflow and treatment parameters that differ significantly from the norm may be monitored, flagged and brought to the attention of clinicians. By determining historical trends using existing patient data and by comparing new patient data with the historical, we expect our software to provide a measurable improvement in the quality of radiotherapy at our centre.

  20. The Facilitative Effect of Transcranial Direct Current Stimulation on Visuospatial Working Memory in Patients with Diabetic Polyneuropathy: A Pre-post Sham-Controlled Study.

    Science.gov (United States)

    Wu, Yi-Jen; Tseng, Philip; Huang, Han-Wei; Hu, Jon-Fan; Juan, Chi-Hung; Hsu, Kuei-Sen; Lin, Chou-Ching

    2016-01-01

    Diabetes mellitus can lead to diabetic polyneuropathy (DPN) and cognitive deficits that manifest as peripheral and central neuropathy, respectively. In this study we investigated the relationship between visuospatial working memory (VSWM) capacity and DPN severity, and attempted to improve VSWM in DPN patients via the use of transcranial direct current stimulation (tDCS). Sixteen DPN patients and 16 age- and education-matched healthy control subjects received Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) and Montreal Cognitive Assessment (MOCA) for baseline cognitive assessment. A forward- and backward-recall computerized Corsi block tapping task (CBT), both with and without a concurrent motor interference task was used to measure VSWM capacity. Each DPN patient underwent a pre-treatment CBT, followed by tDCS or sham treatment, then a post-treatment CBT on two separate days. We found that although patients with severe DPN (Dyck's grade 2a or 2b) showed comparable general intelligence scores on WAIS-IV as their age- and education-matched healthy counterparts, they nonetheless showed mild cognitive impairment (MCI) on MOCA and working memory deficit on digit-span test of WAIS-IV. Furthermore, patients' peripheral nerve conduction velocity (NCV) was positively correlated with their VSWM span in the most difficult CBT condition that involved backward-recall with motor interference such that patients with worse NCV also had lower VSWM span. Most importantly, anodal tDCS over the right DLPFC was able to improve low-performing patients' VSWM span to be on par with the high-performers, thereby eliminating the correlation between NCV and VSWM. In summary, these findings suggest that (1) MCI and severe peripheral neuropathy can coexist with unequal severity in diabetic patients, (2) the positive correlation of VSWM and NCV suggests a link between peripheral and central neuropathies, and (3) anodal tDCS over the right DLPFC can improve DPN patients' VSWM, particularly for the low-performing patients.

  1. 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.

  2. The permeability of poly-disperse porous media and effective particle size

    Science.gov (United States)

    Markicevic, B. I.; Preston, C.; Osterroth, S.; Iliev, O.; Hurwitz, M.

    2015-11-01

    The interactions between the fluid and solid phases in porous media account for the openness and length of the flow path that the fluid needs to travel within. The same reasoning applies for both mono- and poly-disperse media, and is reflected in the adoption of the same permeability models. The only difference is that an effective particle size diameter has to be used for the poly-disperse samples. A filtration experiment is used to form a particle layer, filter cake, consisting of particles of different sizes. Both inflow and outflow particle size distribution are measured by particle counting method, and from their difference, the particle size distribution in the cake is determined. In a set of experiments, the filtration history is altered by changing (i) filtration medium; (ii) suspension flow rate; and (iii) particle concentration, where in all cases investigated the cake permeability remains constant. In order to predict the permeability of poly-disperse cake from the analytical models, the particle size distribution moments are calculated, and the permeability is found for each moment. Comparing the experimental to the analytical permeability values the effective particle size is found, where the permeability calculated by using the harmonic mean of the particle size distribution reproduces the permeability experimental value best. Finally, in the parametric study, reducing the cake porosity and/or lowering the particle retention shifts effective particle size used in the permeability model toward higher moments of the particle size distribution function.

  3. Effect size and power in assessing moderating effects of categorical variables using multiple regression: a 30-year review.

    Science.gov (United States)

    Aguinis, Herman; Beaty, James C; Boik, Robert J; Pierce, Charles A

    2005-01-01

    The authors conducted a 30-year review (1969-1998) of the size of moderating effects of categorical variables as assessed using multiple regression. The median observed effect size (f(2)) is only .002, but 72% of the moderator tests reviewed had power of .80 or greater to detect a targeted effect conventionally defined as small. Results suggest the need to minimize the influence of artifacts that produce a downward bias in the observed effect size and put into question the use of conventional definitions of moderating effect sizes. As long as an effect has a meaningful impact, the authors advise researchers to conduct a power analysis and plan future research designs on the basis of smaller and more realistic targeted effect sizes.

  4. Adding effect sizes to a systematic review on interventions for promoting physical activity among European teenagers

    OpenAIRE

    Crutzen Rik

    2010-01-01

    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-compo...

  5. Experimental investigation of nonlinear optical properties of Ag nanoparticles: Effects of size quantization

    Science.gov (United States)

    Sato, Rodrigo; Ohnuma, Masato; Oyoshi, Keiji; Takeda, Yoshihiko

    2014-09-01

    The effects of size quantization on the nonlinear optical response of Ag nanoparticles are experimentally studied by spectroscopic ellipsometry and femtosecond spectroscopic pump-and-probe techniques. In the vicinity of a localized surface-plasmon resonance (2.0-3.5 eV), we have investigated the optical nonlinearity of Ag particles embedded in silica glass for particle diameters ranging from 3.0 to 16 nm. The intrinsic third-order optical susceptibility χm(3) of Ag particles exhibited significant spectral and size dependences. These results are explained as quantum and dielectric confinements and are compared to the results of theoretical quantum finite-size effects calculation for metallic particles. In light of these results, we discuss the contribution of interband transitions to the size dependence of χm(3). Quantum size effects lead to an increase in nonlinearity in small Ag particles.

  6. 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 h

  7. 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…

  8. The Effect of Camera Angle and Image Size on Source Credibility and Interpersonal Attraction.

    Science.gov (United States)

    McCain, Thomas A.; Wakshlag, Jacob J.

    The purpose of this study was to examine the effects of two nonverbal visual variables (camera angle and image size) on variables developed in a nonmediated context (source credibility and interpersonal attraction). Camera angle and image size were manipulated in eight video taped television newscasts which were subsequently presented to eight…

  9. Effects of growth curve plasticity on size-structured population dynamics

    DEFF Research Database (Denmark)

    Zhang, Lai; Lin, Zhigui; Pedersen, Michael

    2011-01-01

    primarily exerts destabilizing effects on the system but considerably promotes species coexistence, in comparison with the size-independent mechanism. We conclude that the size-dependent mechanism is, to a large extent, a dispensable component of model ingredients when ontogeny is explicitly taken...

  10. The Effects of Mergers and Acquisitions on the Firm Size Distribution

    NARCIS (Netherlands)

    Cefis, E.; Marsili, O.; Schenk, E.J.J

    2006-01-01

    This paper provides new empirical evidence on the effects of mergers and acquisitions on the shape of the firm size distribution (FSD), by using data of the population of manufacturing firms in the Netherlands. Our analysis shows that M&As do not affect the size distribution when we consider the

  11. The effects of mergers and acquisitions on the firm size distribution

    NARCIS (Netherlands)

    Cefis, E.; Marsili, Orietta; Schenk, E.J.J.

    2008-01-01

    This paper provides new empirical evidence on the effects of mergers and acquisitions (M&As) on the shape of the firm size distribution, by using data of the population of manufacturing firms in the Netherlands. Our analysis shows that M&As do not affect the size distribution when we consider the

  12. The effects of mergers and acquisitions on the firm size distribution

    NARCIS (Netherlands)

    E. Cefis (Elena); O. Marsili (Orietta); H. Schenk (Hans)

    2009-01-01

    textabstractThis paper provides new empirical evidence on the effects of mergers and acquisitions (M&As) on the shape of the firm size distribution, by using data of the population of manufacturing firms in the Netherlands. Our analysis shows that M&As do not affect the size distribution when we

  13. Using Shocks to School Enrollment to Estimate the Effect of School Size on Student Achievement

    Science.gov (United States)

    Kuziemko, Ilyana

    2006-01-01

    Previous studies of the connection between school enrollment size and student achievement use cross-sectional econometric models and thus do not account for unobserved heterogeneity across schools. To address this concern, I utilize school-level panel data, and generate first-differences estimates of the effect of school size on achievement.…

  14. Identifying Class Size Effects in Developing Countries: Evidence from Rural Schools in Bolivia.

    Science.gov (United States)

    Urquiola, Miguel

    Although great interest surrounds class size as a policy instrument, inferences on its effects are controversial. Recent work highlights a particular way to consider the endogeneity issues that affect this variable: class size is often correlated with enrollment, which in turn may be related to socioeconomic status (SES). This paper shows why such…

  15. Effect of acorn size on development of northern red oak 1-0 seedlings

    Science.gov (United States)

    Paul P. Kormanik; Shi-Jean S. Sung; T.L. Kormanik; S.E. Schlarbaum; Stanley J. Zarnoch

    1998-01-01

    The effect of acorn size on seedling development was determined for 20 northern red oak (Quercus rubra L.) mother tree selections from the USDA Forest Service's Eastern Tennessee Watauga seed orchard. Acorns from each mother tree were visually separated into three size groups, weighed, and sown separately in forest nurseries located in Georgia,...

  16. More choice is better : Effects of assortment size and composition on assortment evaluations

    NARCIS (Netherlands)

    Koelemeijer, K.; Oppewal, H.

    2005-01-01

    This study focuses on effects of assortment size and composition on assortment evaluation. Data from a choice experiment conducted with members of a large consumer panel suggest that adding any item improves assortment evaluation, regardless of their attributes or the size of the assortment. Althoug

  17. Effect of reference population size and available ancestor genotypes on imputation of Mexican Holstein genotypes

    Science.gov (United States)

    The effects of reference population size and the availability of information from genotyped ancestors on the accuracy of imputation of single nucleotide polymorphisms (SNPs) were investigated for Mexican Holstein cattle. Three scenarios for reference population size were examined: (1) a local popula...

  18. Cobalt particle size effects on catalytic performance for ethanol steam reforming - Smaller is better

    NARCIS (Netherlands)

    Da Silva, Andre L M; Den Breejen, Johan P.; Mattos, Lisiane V.; Bitter, Johannes H.; De Jong, Krijn P.; Noronha, Fábio B.

    2014-01-01

    The effect of the cobalt particle size in the ethanol steam reforming reaction at 773 K for hydrogen production was investigated using cobalt on carbon nanofiber catalysts. It was found that the turnover frequency increases with decreasing Co particle size, which was attributed to the increasing fra

  19. Cobalt particle size effects on catalytic performance for ethanol steam reforming – Smaller is better

    NARCIS (Netherlands)

    Silva, da A.L.M.; Breejen, den J.P.; Mattos, L.V.; Bitter, J.H.; Jong, de K.P.; Noronha, F.B.

    2014-01-01

    The effect of the cobalt particle size in the ethanol steam reforming reaction at 773 K for hydrogen production was investigated using cobalt on carbon nanofiber catalysts. It was found that the turnover frequency increases with decreasing Co particle size, which was attributed to the increasing fra

  20. Effective transverse size of nucleon in high-energy elastic diffractive scattering

    CERN Document Server

    Godizov, A A

    2015-01-01

    The high-energy elastic diffraction of nucleons is considered in the framework of the simplest Regge-eikonal approximation. It is demonstrated explicitly that the effective transverse size of nucleon in this nonperturbative regime is $\\sim$ 0.3 fm and much less than the transverse size of the diffractive interaction region.

  1. 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.

  2. Willingness to Communicate in Iranian EFL Learners: The Effect of Class Size

    Science.gov (United States)

    Khazaei, Zeinab Moradi; Zadeh, Ahmad Moin; Ketabi, Saeed

    2012-01-01

    Willingness to communicate can be considered as one of the important factors in modern language pedagogy which put emphasis on meaningful communication. The present study investigated the effect of class size on the Iranian EFL students' willingness to communicate among three different class sizes. The researcher collected the data through…

  3. Optimal and maximin sample sizes for multicentre cost-effectiveness trials.

    Science.gov (United States)

    Manju, Md Abu; Candel, Math J J M; Berger, Martijn P F

    2015-10-01

    This paper deals with the optimal sample sizes for a multicentre trial in which the cost-effectiveness of two treatments in terms of net monetary benefit is studied. A bivariate random-effects model, with the treatment-by-centre interaction effect being random and the main effect of centres fixed or random, is assumed to describe both costs and effects. The optimal sample sizes concern the number of centres and the number of individuals per centre in each of the treatment conditions. These numbers maximize the efficiency or power for given research costs or minimize the research costs at a desired level of efficiency or power. Information on model parameters and sampling costs are required to calculate these optimal sample sizes. In case of limited information on relevant model parameters, sample size formulas are derived for so-called maximin sample sizes which guarantee a power level at the lowest study costs. Four different maximin sample sizes are derived based on the signs of the lower bounds of two model parameters, with one case being worst compared to others. We numerically evaluate the efficiency of the worst case instead of using others. Finally, an expression is derived for calculating optimal and maximin sample sizes that yield sufficient power to test the cost-effectiveness of two treatments. © The Author(s) 2015.

  4. Flow stress and tribology size effects in scaled down cylinder compression

    Institute of Scientific and Technical Information of China (English)

    GUO Bin; GONG Feng; WANG Chun-ju; SHAN De-bin

    2009-01-01

    Microforming is an effective method to manufacture small metal parts. However, macro forming can not be transferred to microforming directly because of size effects. Flow stress and tribology size effects were studied. Scaled down copper T2 cylinder compression was carried out with the lubrication of castor oil and without lubrication. The results show that the flow stress decreases with decreasing the initial specimen diameter in both lubrication conditions, and the flow stress decreases by 30 MPa with the initial specimen diameter decreasing from 8 mm to 1 mm. The friction factor increases obviously with decreasing the initial specimen diameter in the case of lubricating with castor oil, and the friction factor increases by 0.11 with the initial specimen diameter decreasing from 8mm to 1mm. However, the tribology size effect is not found in the case without lubrication. The reasons of the flow stress and tribology size effects were also discussed.

  5. The effects of class size on English learning at a Thai university

    OpenAIRE

    Watson Todd, Richard

    2013-01-01

    Large classes are the norm and a cause for concern for many language teachers.  Most previous research into large classes has surveyed teachers’ beliefs about the size and problems of large classes.  Surprisingly, there has been no previous research in English language teaching into the effects of class size on learning.  This study examines the relationship between class size and learning for 984 classes of students ranging in size from 10 to 103 students for four fundamental English courses...

  6. Effect of Void Size on the Detonation Pressure of Emulsion Explosives

    Science.gov (United States)

    Hirosaki, Yoshikazu; Murata, Kenji; Kato, Yukio; Itoh, Shigeru

    2002-07-01

    To study the effect of void size, detonation pressure as well as detonation velocity was measured using PVDF pressure gauge for the emulsion explosives sensitized with plastic balloons of five different size ranging from 0.05mm to 2.42mm. The experimental results were compared with the detonation pressure and velocity calculated using KHT code. The experimental results showed that the detonation pressure and velocity were strongly affected by void size, and that the fraction of ammonium nitrate reacted in the reaction zone was strongly dependent on void size.

  7. Antler and Body Size in Black-Tailed Deer: An Analysis of Cohort Effects

    Directory of Open Access Journals (Sweden)

    Johanna C. Thalmann

    2015-01-01

    Full Text Available For long-lived species, environmental factors experienced early in life can have lasting effects persisting into adulthood. Large herbivores can be susceptible to cohort-wide declines in fitness as a result of decreases in forage availability, because of extrinsic factors, including extreme climate or high population densities. To examine effects of cohort-specific extrinsic factors on size of adults, we performed a retrospective analysis on harvest data of 450 male black-tailed deer (Odocoileus hemionus columbianus over 19 years in central California, USA. We determined that population density of females had a more dominant effect than did precipitation on body size of males. Harvest of female deer resulted in increases in the overall size of males, even though a 6-year drought occurred during that treatment period. Body size was most influenced by female population density early in life, while antler size was highly affected by both weather early in life and the year directly before harvest. This study provides insights that improve our understanding of the role of cohort effects in body and antler size by cervids; and, in particular, that reduction in female population density can have a profound effect on the body and antler size of male deer.

  8. The Hall-Petch effect as a manifestation of the general size effect

    Science.gov (United States)

    Li, Y.; Bushby, A. J.; Dunstan, D. J.

    2016-06-01

    The experimental evidence for the Hall-Petch dependence of strength on the inverse square-root of grain size is reviewed critically. Both the classic data and more recent results are considered. While the data are traditionally fitted to the inverse square-root dependence, they also fit well to many other functions, both power law and non-power law. There have been difficulties, recognized for half-a-century, in the inverse square-root expression. It is now explained as an artefact of faulty data analysis. A Bayesian meta-analysis shows that the data strongly support the simple inverse or lnd/d expressions. Since these expressions derive from underlying theory, they are also more readily explicable. It is concluded that the Hall-Petch effect is not to be explained by the variety of theories found in the literature, but is a manifestation of, or to be underlain by the general size effect observed throughout micromechanics, owing to the inverse relationship between the stress required and the space available for dislocation sources to operate.

  9. 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.

  10. 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.

  11. Effect of Sizing on the Interfacial Shear Strength of Carbon Fiber/Epoxy Resin Monofilament Composite

    Institute of Scientific and Technical Information of China (English)

    YANG Yusong; ZHAO Yan; LI Ye; DONG Qi; CHEN Da

    2014-01-01

    The single fiber fragmentation test (SFFT) was used to measure the interfacial shear strength (IFSS) of sized and unsized CF800/epoxy resin monofilament composite in order to evaluate the effect of sizing respectively. Besides, the interfacial reinforcing mechanism was explored by analyzing the surface morphology of the carbon fibers, the wettability between the carbon fibers and the epoxy resin, and the chemical characteristics of the fiber surface. Moreover, the effect of sizing on heat and humidity resistance of interface was investigated by aging test. The results show that sizing improves IFSS of CF800/epoxy resin monofilament composite by 59% through increasing the functional groups containing oxygen and through enhancing wettability, while after sizing the heat and humidity resistance of interface is decreased.

  12. Computing Effect Size Measures with ViSta-The Visual Statistics System

    Directory of Open Access Journals (Sweden)

    Nuria Cortada de Kohan

    2009-03-01

    Full Text Available Effect size measures are recognized as a necessary complement to statistical hypothesis testing because they provide important information that such tests alone cannot offer. In this paper we: a briefly review the importance of effect size measures, b describe some calculation algorithms for the case of the difference between two means, and c provide a new and easy-to-use computer program to perform these calculations within ViSta “The Visual Statistics System”. A worked example is also provided to illustrate some practical issues concerning the interpretation and limits of effect size computation. The audience for this paper includes novice researchers as well as ViSta’s user interested on applying effect size measures.

  13. 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.

  14. The effect of birth weight of boars and litter size in which were 1 ...

    African Journals Online (AJOL)

    Eugenia

    2017-05-22

    May 22, 2017 ... The skinfold thickness (two layers of scrotal skin) were subtracted from initial measurements of length and width of each testis. Testis volume was ... Table 2 Effects of birth weight and litter size on growth performance of boars.

  15. Effect of particle size and distribution of the sizing agent on the carbon fibers surface and interfacial shear strength (IFSS) of its composites

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R.L. [Open Project of State Key Laboratory Breeding Base for Mining Disaster Prevention and Control, Shandong University of Science and Technology (China); School of Materials Science and Engineering, Shandong University of Science and Technology, 266590 Qingdao (China); Liu, Y. [School of Materials Science and Engineering, Shandong University of Science and Technology, 266590 Qingdao (China); Huang, Y.D., E-mail: rlzhit@126.com [School of Chemical Engineering and Technology, State Key laboratory of Urban Water Resource and Environment Department of Applied Chemistry, Harbin Institute of Technology, 150001 Harbin (China); Liu, L. [School of Chemical Engineering and Technology, State Key laboratory of Urban Water Resource and Environment Department of Applied Chemistry, Harbin Institute of Technology, 150001 Harbin (China)

    2013-12-15

    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.

  16. A review of the findings and theories on surface size effects on visual attention

    DEFF Research Database (Denmark)

    Peschel, Anne Odile; Orquin, Jacob Lund

    2013-01-01

    That surface size has an impact on attention has been well-known in advertising research for almost a century; however, theoretical accounts of this effect have been sparse. To address this issue, we review studies on surface size effects on eye movements in this paper. While most studies find th...... suggest that advertisers should take into account how objects in the visual scene interact in order to optimize attention to, for instance, brands and logos....

  17. Finite-size effects on semi-directed Barabási-Albert networks

    Science.gov (United States)

    Radwan, M. A.; Sumour, Muneer A.; Elbitar, A. M.; Shabat, M. M.; Lima, F. W. S.

    2016-04-01

    In scale-free Barabási-Albert (BA) networks, we study the finite-size effect at different number m of neighbors. So, we investigate the effects of finite network size N for the recently developed semi-directed BA networks (SDBA1 and SDBA2) at fixed 2≤m≤300) and show and explain the gap in the distribution of the number k(i) of neighbors of the nodes i.

  18. A Unified Guide to Two Opposite Size Effects in Nano Elastic Materials

    Institute of Scientific and Technical Information of China (English)

    TANG Yi-Zhe; ZHENG Zhi-Jun; XIA Meng-Fen; BAI Yi-Long

    2009-01-01

    The microstructural variation near surface of nano elastic materials is analyzed based on different potentials.The atomic/molecular mechanism underlying the variation and its effect on elastic modulus are such that the nature of long-range interactions(attractive or repulsive)in the atomic/molecular potentials essentially governs the variation near surface(looser or tighter)and results in two opposite size effects(decreasing or increasing modulus)with decreasing size.

  19. Can Downsizing College Class Sizes Augment Student Outcomes? An Investigation of the Effects of Class Size on Student Learning

    Science.gov (United States)

    Chapman, Lauren; Ludlow, Larry

    2010-01-01

    This investigation uses student course evaluations to examine the relationship between class size and perceived student learning, after student effort and instructor quality have been taken into account. This study found that despite the efforts by students and instructors, class size had a significant negative relationship with perceived student…

  20. Size measurement of nano-particles using self-mixing effect

    Institute of Scientific and Technical Information of China (English)

    Huarui Wang; Jianqi Shen

    2008-01-01

    In this letter, the technique of laser self-mixing effect is employed for nano-particle size analysis. In contrast to the photon correlation spectroscopy (PCS) and photon cross correlation spectroscopy (PCCS),the main advantages of this technique are sensitive, compact, low-cost, and simple experimental setup etc.An improved Kaczmarz projection method is developed in the inversion problem to extract the particle size distribution. The experimental results prove that nano-particle size can be measured reasonably by using the self-mixing effect technique combined with the improved projection algorithm.

  1. The effect of size on the strength of FCC metals at elevated temperatures: Annealed copper

    OpenAIRE

    Wheeler, J.M.; Kirchlechner, C.; Micha, J.S.; Michler, J.; Kiener, D.

    2016-01-01

    International audience; As the length scale of sample dimensions is reduced to the micron and sub-micron scales, the strength of various materials has been observed to increase with decreasing size, a fact commonly referred to as the 'sample size effect'. In this work, the influence of temperature on the sample size effect in copper is investigated using in situ microcompression testing at 25, 200 and 400 degrees C in the SEM on vacuum-annealed copper structures, and the resulting deformed st...

  2. Size effect on cubic and prismatic compressive strength of cement paste

    Institute of Scientific and Technical Information of China (English)

    苏捷; 叶缙垚; 方志; 赵明华

    2015-01-01

    A series of compression tests were conducted on 150 groups of cement paste specimens with side lengths ranging from 40 mm to 200 mm. The specimens include cube specimens and prism specimens with height to width ratio of 2. The experiment results show that size effect exists in the cubic compressive strength and prismatic compressive strength of the cement paste, and larger specimens resist less in terms of strength than smaller ones. The cubic compressive strength and the prismatic compressive strength of the specimens with side length of 200 mm are respectively about 91% and 89% of the compressive strength of the specimens with the side length of 40 mm. Water to binder ratio has a significant influence on the size effect of the compressive strengths of the cement paste. With a decrease in the water to binder ratio, the size effect is significantly enhanced. When the water to binder ratio is 0.2, the size effects of the cubic compressive strength and the prismatic compressive strength of the cement paste are 1.6 and 1.4 times stronger than those of a water to binder ratio of 0.6. Furthermore, a series of formulas are proposed to calculate the size effect of the cubic compressive strength and the prismatic compressive strength of cement paste, and the results of the size effect predicted by the formulas are in good agreement with the experiment results.

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

    Science.gov (United States)

    Evans, Joyce M; Wang, Siqi; Greb, Christopher; Kostas, Vladimir; Knapp, Charles F; Zhang, Qingguang; Roemmele, Eric S; Stenger, Michael B; Randall, David C

    2017-01-01

    Key Points Summary We 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 index. When

  4. Gender versus brain size effects on subcortical gray matter volumes in the human brain.

    Science.gov (United States)

    Tang, Tianyu; Jiao, Yun; Wang, Xunheng; Lu, Zuhong

    2013-11-27

    Previous studies had reported that volume differences of gray matter (GM) in subcortical regions of the human brain were mainly caused by gender. Meanwhile, other studies had found that the distribution of GM in the human brain varied based on individual brain sizes. Main effects of volume differences of GM in subcortical regions remain unclear. Therefore, the goals of this study are twofold, namely, to determine the main effects of volume differences of GM in subcortical regions of the human brain and to investigate the independent or joint contribution of gender and brain size to subcortical volume differences. In this study, 40 male and 40 female subjects with comparable brain sizes were selected from a population of 198 individuals. The sample was divided into the following four groups: male and female groups with comparably large brain sizes and male and female groups with comparably small brain sizes. The main effects of gender and of brain size and interactions between both factors in subcortical GM volumes were examined by analyses of covariance (ANCOVAs) using a 2×2 design matrix. Volumes of GM in subcortical regions were extracted and measured by an automatic segmentation method. Furthermore, we used two datasets to test the reliability of our methods. In both datasets, we found significant brain size effects in the right amygdala and the bilateral caudate nucleus and significant gender effects in the bilateral putamen. No interactions between brain size and gender were found. In conclusion, both gender and brain size independently contributed to volume distribution in different subcortical areas of the human brain.

  5. Effect of cell-size on the energy absorption features of closed-cell aluminium foams

    Science.gov (United States)

    Nammi, S. K.; Edwards, G.; Shirvani, H.

    2016-11-01

    The effect of cell-size on the compressive response and energy absorption features of closed-cell aluminium (Al) foam were investigated by finite element method. Micromechanical models were constructed with a repeating unit-cell (RUC) which was sectioned from tetrakaidecahedra structure. Using this RUC, three Al foam models with different cell-sizes (large, medium and small) and all of same density, were built. These three different cell-size pieces of foam occupy the same volume and their domains contained 8, 27 and 64 RUCs respectively. However, the smaller cell-size foam has larger surface area to volume ratio compared to other two. Mechanical behaviour was modelled under uniaxial loading. All three aggregates (3D arrays of RUCs) of different cell-sizes showed an elastic region at the initial stage, then followed by a plateau, and finally, a densification region. The smaller cell size foam exhibited a higher peak-stress and a greater densification strain comparing other two cell-sizes investigated. It was demonstrated that energy absorption capabilities of smaller cell-size foams was higher compared to the larger cell-sizes examined.

  6. Effects of Particle Size on the Attenuated Total Reflection Spectrum of Minerals.

    Science.gov (United States)

    Udvardi, Beatrix; Kovács, István J; Fancsik, Tamás; Kónya, Péter; Bátori, Miklósné; Stercel, Ferenc; Falus, György; Szalai, Zoltán

    2017-06-01

    This study focuses on particle size effect on monomineralic powders recorded using attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy. Six particle size fractions of quartz, feldspar, calcite, and dolomite were prepared (size. As particle size increases, the intensity and area of IR bands usually decrease while the width of bands increases. The band positions usually shifted to higher wavenumbers with decreasing particle size. Infrared spectra of minerals are the most intensive in the particle size fraction of 2-4 µm. However, if the particle size is very small (size are compared, as in regression analysis for modal predictions using ATR FT-IR, it is also important to report the grain size distribution or surface area of samples. The band area of water (3000-3620 cm(-1)) is similar in each mineral fraction, except for the particles below 2 µm. It indicates that the finest particles could have disproportionately more water adsorbed on their larger surface area. Thus, these higher wavenumbers of the ATR FT-IR spectra may be more sensitive to this spectral interference if the number of particles below 2 µm is considerable. It is also concluded that at least a proportion of the moisture could be very adhesive to the particles due to the band shift towards lower wavenumbers in the IR range of 3000-3620 cm(-1).

  7. Effects of allometry, productivity and lifestyle on rates and limits of body size evolution

    Science.gov (United States)

    Okie, Jordan G.; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Evans, Alistair R.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Saarinen, Juha J.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica; Uhen, Mark D.; Sibly, Richard M.

    2013-01-01

    Body size affects nearly all aspects of organismal biology, so it is important to understand the constraints and dynamics of body size evolution. Despite empirical work on the macroevolution and macroecology of minimum and maximum size, there is little general quantitative theory on rates and limits of body size evolution. We present a general theory that integrates individual productivity, the lifestyle component of the slow–fast life-history continuum, and the allometric scaling of generation time to predict a clade's evolutionary rate and asymptotic maximum body size, and the shape of macroevolutionary trajectories during diversifying phases of size evolution. We evaluate this theory using data on the evolution of clade maximum body sizes in mammals during the Cenozoic. As predicted, clade evolutionary rates and asymptotic maximum sizes are larger in more productive clades (e.g. baleen whales), which represent the fast end of the slow–fast lifestyle continuum, and smaller in less productive clades (e.g. primates). The allometric scaling exponent for generation time fundamentally alters the shape of evolutionary trajectories, so allometric effects should be accounted for in models of phenotypic evolution and interpretations of macroevolutionary body size patterns. This work highlights the intimate interplay between the macroecological and macroevolutionary dynamics underlying the generation and maintenance of morphological diversity. PMID:23760865

  8. Effects of allometry, productivity and lifestyle on rates and limits of body size evolution.

    Science.gov (United States)

    Okie, Jordan G; Boyer, Alison G; Brown, James H; Costa, Daniel P; Ernest, S K Morgan; Evans, Alistair R; Fortelius, Mikael; Gittleman, John L; Hamilton, Marcus J; Harding, Larisa E; Lintulaakso, Kari; Lyons, S Kathleen; Saarinen, Juha J; Smith, Felisa A; Stephens, Patrick R; Theodor, Jessica; Uhen, Mark D; Sibly, Richard M

    2013-08-01

    Body size affects nearly all aspects of organismal biology, so it is important to understand the constraints and dynamics of body size evolution. Despite empirical work on the macroevolution and macroecology of minimum and maximum size, there is little general quantitative theory on rates and limits of body size evolution. We present a general theory that integrates individual productivity, the lifestyle component of the slow-fast life-history continuum, and the allometric scaling of generation time to predict a clade's evolutionary rate and asymptotic maximum body size, and the shape of macroevolutionary trajectories during diversifying phases of size evolution. We evaluate this theory using data on the evolution of clade maximum body sizes in mammals during the Cenozoic. As predicted, clade evolutionary rates and asymptotic maximum sizes are larger in more productive clades (e.g. baleen whales), which represent the fast end of the slow-fast lifestyle continuum, and smaller in less productive clades (e.g. primates). The allometric scaling exponent for generation time fundamentally alters the shape of evolutionary trajectories, so allometric effects should be accounted for in models of phenotypic evolution and interpretations of macroevolutionary body size patterns. This work highlights the intimate interplay between the macroecological and macroevolutionary dynamics underlying the generation and maintenance of morphological diversity.

  9. Ultrafine particle size distributions near freeways: Effects of differing wind directions on exposure

    Science.gov (United States)

    Kozawa, Kathleen H.; Winer, Arthur M.; Fruin, Scott A.

    2012-12-01

    High ambient ultrafine particle (UFP) concentrations may play an important role in the adverse health effects associated with living near busy roadways. However, UFP size distributions change rapidly as vehicle emissions dilute and age. These size changes can influence UFP lung deposition rates and dose because deposition in the respiratory system is a strong function of particle size. Few studies to date have measured and characterized changes in near-road UFP size distributions in real-time, thus missing transient variations in size distribution due to short-term fluctuations in wind speed, direction, or particle dynamics. In this study we measured important wind direction effects on near-freeway UFP size distributions and gradients using a mobile platform with 5-s time resolution. Compared to more commonly measured perpendicular (downwind) conditions, parallel wind conditions appeared to promote formation of broader and larger size distributions of roughly one-half the particle concentration. Particles during more parallel wind conditions also changed less in size with downwind distance and the fraction of lung-deposited particle number was calculated to be 15% lower than for downwind conditions, giving a combined decrease of about 60%. In addition, a multivariate analysis of several variables found meteorology, particularly wind direction and temperature, to be important in predicting UFP concentrations within 150 m of a freeway (R2 = 0.46, p = 0.014).

  10. 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…

  11. 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…

  12. 77 FR 53769 - Receipts-Based, Small Business Size Standard; Confirmation of Effective Date

    Science.gov (United States)

    2012-09-04

    ... and 171 RIN 3150-AJ14 Receipts-Based, Small Business Size Standard; Confirmation of Effective Date AGENCY: Nuclear Regulatory Commission. ACTION: Direct final rule; confirmation of effective date. SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is confirming the effective date of August 22, 2012,...

  13. 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.

  14. Effect of pressure on the size of magnetite nanoparticles in the coprecipitation synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Yazdani, F., E-mail: fyazdani@ccerci.ac.ir [Chemical Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran (Iran, Islamic Republic of); Edrissi, M., E-mail: edrisi@aut.ac.ir [Chemical Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2010-07-25

    The effect of pressure on the size of magnetite nanoparticles synthesized by the coprecipitation technique was studied. It is generally believed that pressure has negligible effects, if any, on liquid and solid reactions. However, in this work it was shown that pressure has a significant effect on the size of magnetite nanoparticles. This could be attributed to the very high surface-to-volume ratio of nanosized particles and to some other physical properties of magnetite, such as supersaturation and surface tension. The increase in the size of the nanoparticles is explained by the change in the Gibbs free energy value during crystallization from a homogeneous supersaturated solution at higher pressures. This phenomenon could find important applications especially in biomedicine where a limitation on the maximum size of the nanoparticles will be desired.

  15. Numerical study of gap size ratio effect for noncondensable gas ventilation in condensers

    Energy Technology Data Exchange (ETDEWEB)

    Je, Junho; Kim, Soo Jea; Kim, Moo Hwan [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of); Choi, Chiwoong [Univ. of Wyoming, Wyoming (United States)

    2012-01-15

    A numerical analysis was carried out to estimate the effect of the gap size ratio on the performance of condensers under noncondensable gas ventilation using the porous medium approach (PMA). In the PMA, the details of the tube bundle in the condenser are considered to be those of a porous medium, and the flow resistance term is added in the momentum equation. Three dimensional analysis of the condensation for a McAllister condenser was conducted with the PMA using Fluent and user defined functions (UDFs). The gap size effect on the condensation was negligible under pure steam conditions. However, the gap size effect was dominant in condensation with noncondensable gas and external venting. As the gap size decreased, the condensation rate increased for noncondensable gas in an external venting system.

  16. GESP: A computer program for modeling genetic effective population size, inbreeding, and divergence in substructured populations.

    Science.gov (United States)

    Olsson, Fredrik; Laikre, Linda; Hössjer, Ola; Ryman, Nils

    2017-03-24

    The genetically effective population size (Ne) is of key importance for quantifying rates of inbreeding and genetic drift, and is often used in conservation management to set targets for genetic viability. The concept was developed for single, isolated populations and the mathematical means for analyzing the expected Ne in complex, subdivided populations have previously not been available. We recently developed such analytical theory and central parts of that work have now been incorporated into a freely available software tool presented here. GESP (Genetic Effective population size, inbreeding, and divergence in Substructured Populations) is R-based and designed to model short and long term patterns of genetic differentiation and effective population size of subdivided populations. The algorithms performed by GESP allow exact computation of global and local inbreeding and eigenvalue effective population size, predictions of genetic divergence among populations (GST) as well as departures from random mating (FIS, FIT) while varying i) subpopulation census and effective size, separately or including trend of the global population size, ii) rate and direction of migration between all pairs of subpopulations, iii) degree of relatedness and divergence among subpopulations, iv) ploidy (haploid or diploid), and v) degree of selfing. Here, we describe GESP and exemplify its use in conservation genetics modeling. This article is protected by copyright. All rights reserved.

  17. 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.

  18. Orthographic neighborhood size effect in Chinese character naming: orthographic and phonological activations.

    Science.gov (United States)

    Li, Qing-Lin; Bi, Hong-Yan; Wei, Tong-Qi; Chen, Bao-Guo

    2011-01-01

    The present study examined the effects of orthographic neighborhood (N) size on the cognitive processes underlying Chinese character reading. Previous research has shown increasing N size facilitates word naming and recognition performance in alphabetic languages. Experiment 1 revealed that a large N size was associated with a general inhibition of processes underlying character reading, in contrast to previous findings with alphabetic languages. This inhibitory effect was influenced by regularity and consistency. Experiment 2 sought to assess the effects of higher-frequency neighbors on character naming performance. The results revealed that higher-frequency neighbors with different pronunciation to the target interfered with the phonological retrieval of targets. We propose that this type of interference may have caused the N size effect observed in Experiment 1. The results of Experiment 3 revealed that a large N size facilitated target naming in the absence of higher-frequency neighbors. The current results shed light on the processes underlying character naming, and we propose possible cognitive mechanisms of the N size effect on Chinese character naming. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. The Effect of Fines in Mixed Size Sediment Transport in a Gravel Bed

    Science.gov (United States)

    Hill, K. M.; Baumgardner, S.; Gaffney, J.; Wilcock, P.; Paola, C.

    2011-12-01

    Washload is a widely recognized concept that remains difficult to define. In a gravel-bed river, washload has been defined as those sizes present in the bed only in small proportions. It has also been defined as the portion of transported sediment that has little effect on bed material transport. We experimentally investigate the impact of fine sediment on the mobility and composition of a gravel bed. We conducted flume experiments using a constant water discharge and feed rate of gravel. After reaching steady state, we doubled the feed rate by feeding sediment of finer size, using size ratios from 1:1 to 1:16. As we decrease the size of the fine particles relative to the size of the gravel particles, the system transitions between three regimes. (1) For particle size ratios close to one, the bed slope increases to supply the additional shear stress needed to transport the additional load of similar-sized particles. (2) For intermediate particle size ratios the increased fines content increases the mobility of the sediment mix, resulting in a decreased bed slope. The bed composition is a mix of fine and coarse grains. (3) For the largest particle size ratios (the smallest fines), the additional fines travel primarily in suspension and cause essentially no change in bed slope, though the subsurface becomes clogged with fine sediment. The behavior for near-unity and intermediate particle size ratios can be predicted using a mixed-size bed-material transport formula. For the mixtures with the smallest fine particles, the presence of fines has little effect on the mobility of the gravel and thus the total transport can no longer be predicted with a bed material transport formula. These results provide useful insights concerning the nature of wash load. The effect of sediment feed on gravel mobility and bed slope is not controlled solely by the amount of fines in the bed (the first definition of wash load), but also depends strongly on the relative grain size of the

  20. Feasibility of sizing metallic nanoparticles in concentrated suspensions from effective optical properties

    Science.gov (United States)

    Morales-Luna, G.; Márquez-Islas, R.; Vázquez-Estrada, O.; Contreras-Tello, H.; García-Valenzuela, A.

    2015-08-01

    We explore using measurements of the effective refractive index of a metallic nanofluid to estimate the size of the particles in it. We assume the nanofluid consists of spherical metallic nanoparticles suspended in a transparent base liquid and discuss a way of measuring the real and imaginary parts of the effective refractive index for concentrated nanofluids to about 1% in particles' volume concentration. Specifically, we consider the case of copper nanoparticles suspended in water. We propose an unambiguous effective optical parameter as a candidate to evidence the particle size, potentially in real time. Limitations due to dependent scattering effects in concentrated nanofluids are briefly stated.

  1. 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.

  2. 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...

  3. Effect of catalyst concentration on size, morphology and optical properties of silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Ekta; Ritu,; Kumar, Sacheen, E-mail: sacheen3@gmail.com [Department of Electronics science, Kurukshetra University, Kurukshetra, Haryana, India-136119 (India); Kumar, Dinesh

    2016-05-06

    Today, nanomaterials play a key role in various fields such as electronics, aerospace, pharmaceuticals and biomedical because of their unique physical, chemical and biological properties which are different from bulk materials. Nano sized silica particles have gained the prominent position in scientific research and have wide applications. The sol-gel method is the best method to synthesize silica nanoparticles because of its potential to produce monodispersed with narrow size distribution at mild conditions. The silica nanoparticles were obtained by hydrolysis of tetraethyl orthosilicate (TEOS) in ethanol act as solvent. The synthesized nanoparticles were characterized by Field Emission Scanning electron Microscope (FE-SEM), UV Spectrometer. The smallest size of silica particles is around 150nm examined by using FE-SEM. The optical properties and band structure was analyzed using UV-visible spectroscopy which is found to be increase by reducing the size of particles. Concentration effect of catalyst on the size, morphology and optical properties were analyzed.

  4. Effect of catalyst concentration on size, morphology and optical properties of silica nanoparticles

    Science.gov (United States)

    Arora, Ekta; Ritu, Kumar, Sacheen; Kumar, Dinesh

    2016-05-01

    Today, nanomaterials play a key role in various fields such as electronics, aerospace, pharmaceuticals and biomedical because of their unique physical, chemical and biological properties which are different from bulk materials. Nano sized silica particles have gained the prominent position in scientific research and have wide applications. The sol-gel method is the best method to synthesize silica nanoparticles because of its potential to produce monodispersed with narrow size distribution at mild conditions. The silica nanoparticles were obtained by hydrolysis of tetraethyl orthosilicate (TEOS) in ethanol act as solvent. The synthesized nanoparticles were characterized by Field Emission Scanning electron Microscope (FE-SEM), UV Spectrometer. The smallest size of silica particles is around 150nm examined by using FE-SEM. The optical properties and band structure was analyzed using UV-visible spectroscopy which is found to be increase by reducing the size of particles. Concentration effect of catalyst on the size, morphology and optical properties were analyzed.

  5. Orientation dependent size effects in single crystalline anisotropic nanoplates with regard to surface energy

    Energy Technology Data Exchange (ETDEWEB)

    Assadi, Abbas, E-mail: assadi@aut.ac.ir; Salehi, Manouchehr, E-mail: msalehi@aut.ac.ir; Akhlaghi, Mehdi, E-mail: makhlagi@aut.ac.ir

    2015-07-17

    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.

  6. 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.

  7. Finite-size effects in a model for plasticity of amorphous composites

    DEFF Research Database (Denmark)

    Tyukodi, Botond; Lemarchand, Claire; Hansen, Jesper Schmidt

    2016-01-01

    We discuss the plastic behavior of an amorphous matrix reinforced by hard particles. A mesoscopic depinning-like model accounting for Eshelby elastic interactions is implemented. Only the effect of a plastic disorder is considered. Numerical results show a complex size dependence of the effective...... flow stress of the amorphous composite. In particular, the departure from the mixing law shows opposite trends associated to the competing effects of the matrix and the reinforcing particles, respectively. The reinforcing mechanisms and their effects on localization are discussed. Plastic strain...... is shown to gradually concentrate on the weakest band of the system. This correlation of the plastic behavior with the material structure is used to design a simple analytical model. The latter nicely captures reinforcement size effects in (logN/N)1/2, where N is the linear size of the system, observed...

  8. 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.

  9. An Empirical Bayes Mixture Model for Effect Size Distributions in Genome-Wide Association Studies

    DEFF Research Database (Denmark)

    Thompson, Wesley K.; Wang, Yunpeng; Schork, Andrew J.

    2015-01-01

    Characterizing the distribution of effects from genome-wide genotyping data is crucial for understanding important aspects of the genetic architecture of complex traits, such as number or proportion of non-null loci, average proportion of phenotypic variance explained per non-null effect, power...... for discovery, and polygenic risk prediction. To this end, previous work has used effect-size models based on various distributions, including the normal and normal mixture distributions, among others. In this paper we propose a scale mixture of two normals model for effect size distributions of genome...... of variance explained by genotyped SNPs, CD and SZ have a broadly dissimilar genetic architecture, due to differing mean effect size and proportion of non-null loci....

  10. Generalized eta and omega squared statistics: measures of effect size for some common research designs.

    Science.gov (United States)

    Olejnik, Stephen; Algina, James

    2003-12-01

    The editorial policies of several prominent educational and psychological journals require that researchers report some measure of effect size along with tests for statistical significance. In analysis of variance contexts, this requirement might be met by using eta squared or omega squared statistics. Current procedures for computing these measures of effect often do not consider the effect that design features of the study have on the size of these statistics. Because research-design features can have a large effect on the estimated proportion of explained variance, the use of partial eta or omega squared can be misleading. The present article provides formulas for computing generalized eta and omega squared statistics, which provide estimates of effect size that are comparable across a variety of research designs.

  11. Size and refinement edge-shape effects of graphene quantum dots on UV–visible absorption

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ruiqiang; Qi, Shifei; Jia, Jianfeng [School of Chemistry and Materials Science, Shanxi Normal University, Linfen 041004 (China); Key Laboratory of Magnetic Molecules and Magnetic Information Materials, Ministry of Education, Linfen 041004 (China); Torre, Bryna [Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY 14260 (United States); Zeng, Hao [School of Chemistry and Materials Science, Shanxi Normal University, Linfen 041004 (China); Department of Physics, University at Buffalo, The State University of New York, Buffalo, NY 14260 (United States); Wu, Haishun [School of Chemistry and Materials Science, Shanxi Normal University, Linfen 041004 (China); Key Laboratory of Magnetic Molecules and Magnetic Information Materials, Ministry of Education, Linfen 041004 (China); Xu, Xiaohong, E-mail: xuxiaohong_ly@163.com [School of Chemistry and Materials Science, Shanxi Normal University, Linfen 041004 (China); Key Laboratory of Magnetic Molecules and Magnetic Information Materials, Ministry of Education, Linfen 041004 (China)

    2015-02-25

    Highlights: • The size effect affects both the visible light absorption and the zigzag edge state. • Zigzag edge state is important than armchair edge state for visible light absorption. • The Seam atoms should be noted for the randomly shaped GQDs. - Abstract: Using the ab initio density-functional theory method, we calculated the size effect and edge shape effect on UV–visible light absorption of different shapes of graphene quantum dots (GQDs). There are two interesting findings in this study. First, the edge shape effect increase with increasing the size of square GQDs. Second, the Seam atoms, located at the boundary between zigzag and armchair edges, hardly contribute to the strongest visible light absorption. This refinement of the edge-shape effect can be found in rectangular, triangular and hexagonal GQDs. This new finding will be useful in applications of GQDs in the visible light absorption nanodevices.

  12. 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.

  13. 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.

  14. Effects of soil surface roughness on interrill erosion processes and sediment particle size distribution

    Science.gov (United States)

    Ding, Wenfeng; Huang, Chihua

    2017-10-01

    Soil surface roughness significantly impacts runoff and erosion under rainfall. Few previous studies on runoff generation focused on the effects of soil surface roughness on the sediment particle size distribution (PSD), which greatly affects interrill erosion and sedimentation processes. To address this issue, a rainfall-simulation experiment was conducted with treatments that included two different initial soil surface roughnesses and two rainfall intensities. Soil surface roughness was determined by using photogrammetric method. For each simulated event, runoff and sediment samples were collected at different experimental times. The effective (undispersed) PSD of each sediment sample and the ultimate (after dispersion) PSD were used to investigate the detachment and transport mechanisms involved in sediment movement. The results show that soil surface roughness significantly delayed runoff initiation, but had no significant effect on the steady runoff rate. However, a significant difference in the soil loss rate was observed between the smooth and rough soil surfaces. Sediments from smooth soil surfaces were more depleted in clay-size particles, but more enriched in sand-size particles than those from rough soil surfaces, suggesting that erosion was less selective on smooth than on rough soil surfaces. The ratio of different sizes of transported sediment to the soil matrix indicates that most of the clay was eroded in the form of aggregates, silt-size particles were transported mainly as primary particles, and sand-size particles were predominantly aggregates of finer particles. Soil surface roughness has a crucial effect on the sediment size distribution and erosion processes. Significant differences of the enrichment ratios for the effective PSD and the ultimate PSD were observed under the two soil surface roughness treatments. These findings demonstrate that we should consider each particle size separately rather than use only the total sediment discharge in

  15. Evaluation of granulated lactose as a carrier for DPI formulations 1: effect of granule size.

    Science.gov (United States)

    Du, Ping; Du, Ju; Smyth, Hugh D C

    2014-12-01

    The objective of this study was to investigate the effect of large granulated lactose carrier particle systems on aerosol performance of dry powder inhaler formulations. Granulated lactose carriers with average sizes ranging from 200 to 1,000 μm were prepared and subsequently fractionated into separate narrow size powders. The fractionated granulated lactose (GL) samples were characterized in terms of size, specific surface area, surface roughness, morphology, density, flowability, and solid-state. The in vitro aerosolization performance was performed on the different size fractions of GL samples from a commercial inhaler device (Aerolizer®) with a model formulation (2% w/w salbutamol sulfate). The cascade impaction parameters employed were 60 or 90 L/min with standard (aperture size, 0.6 mm) or modified piercing holes (aperture size, 1.2 mm) of the inhaler loaded capsules. It was shown that the largest size fraction formulation (850-1000 μm) had a slight improvement in the fine particle fraction (FPF) compared to immediately preceding size fractions, explained by a smaller adhesive force between drug and carrier. Compared to commercial piercing holes, enlarged piercing holes generated a slight decreasing trend of FPF as the lactose powder sizes increased from 200-250 μm to 600-850 μm, perhaps due to the reduced detachment force by flow forces. The size, surface roughness, density, and flowability of lactose carrier as well as device design all contributed to the aerosol dispersion performance of granulated lactose-based adhesive mixtures. It was concluded that poorer or enhanced redispersion performance is not an inherent property to the significantly large size of granulated lactose carriers as previously contended.

  16. Leveraging the happy meal effect: Substituting food with modest nonfood incentives decreases portion size choice.

    Science.gov (United States)

    Reimann, Martin; Bechara, Antoine; MacInnis, Deborah

    2015-09-01

    Despite much effort to decrease food intake by altering portion sizes, "super-sized" meals are the preferred choice of many. This research investigated the extent to which individuals can be subtly incentivized to choose smaller portion sizes. Three randomized experiments (2 in the lab and 1 in the field) established that individuals' choice of full-sized food portions is reduced when they are given the opportunity to choose a half-sized version with a modest nonfood incentive. This substitution effect was robust across different nonfood incentives, foods, populations, and time. Experiment 1 established the effect with children, using inexpensive headphones as nonfood incentives. Experiment 2--a longitudinal study across multiple days--generalized this effect with adults, using the mere chance to win either gift cards or frequent flyer miles as nonfood incentives. Experiment 3 demonstrated the effect among actual restaurant customers who had originally planned to eat a full-sized portion, using the mere chance to win small amounts of money. Our investigation broadens the psychology of food portion choice from perceptual and social factors to motivational determinants.

  17. The effect of size on the strength of FCC metals at elevated temperatures: annealed copper.

    Science.gov (United States)

    Wheeler, Jeffrey M; Kirchlechner, Christoph; Micha, Jean-Sébastien; Michler, Johann; Kiener, Daniel

    2016-12-01

    As the length scale of sample dimensions is reduced to the micron and sub-micron scales, the strength of various materials has been observed to increase with decreasing size, a fact commonly referred to as the 'sample size effect'. In this work, the influence of temperature on the sample size effect in copper is investigated using in situ microcompression testing at 25, 200 and 400 °C in the SEM on vacuum-annealed copper structures, and the resulting deformed structures were analysed using X-ray μLaue diffraction and scanning electron microscopy. For pillars with sizes between 0.4 and 4 μm, the size effect was measured to be constant with temperature, within the measurement precision, up to half of the melting point of copper. It is expected that the size effect will remain constant with temperature until diffusion-controlled dislocation motion becomes significant at higher temperatures and/or lower strain rates. Furthermore, the annealing treatment of the copper micropillars produced structures which yielded at stresses three times greater than their un-annealed, FIB-machined counterparts.

  18. Ionic size effects to molecular solvation energy and to ion current across a channel resulted from the nonuniform size-modified PNP equations.

    Science.gov (United States)

    Qiao, Yu; Tu, Bin; Lu, Benzhuo

    2014-05-07

    Ionic finite size can impose considerable effects to both the equilibrium and non-equilibrium properties of a solvated molecular system, such as the solvation energy, ionic concentration, and transport in a channel. As discussed in our former work [B. Lu and Y. C. Zhou, Biophys. J. 100, 2475 (2011)], a class of size-modified Poisson-Boltzmann (PB)/Poisson-Nernst-Planck (PNP) models can be uniformly studied through the general nonuniform size-modified PNP (SMPNP) equations deduced from the extended free energy functional of Borukhov et al. [I. Borukhov, D. Andelman, and H. Orland, Phys. Rev. Lett. 79, 435 (1997)] This work focuses on the nonuniform size effects to molecular solvation energy and to ion current across a channel for real biomolecular systems. The main contributions are: (1) we prove that for solvation energy calculation with nonuniform size effects (through equilibrium SMPNP simulation), there exists a simplified approximation formulation which is the same as the widely used one in PB community. This approximate form avoids integration over the whole domain and makes energy calculations convenient. (2) Numerical calculations show that ionic size effects tend to negate the solvation effects, which indicates that a higher molecular solvation energy (lower absolute value) is to be predicted when ionic size effects are considered. For both calculations on a protein and a DNA fragment systems in a 0.5M 1:1 ionic solution, a difference about 10 kcal/mol in solvation energies is found between the PB and the SMPNP predictions. Moreover, it is observed that the solvation energy decreases as ionic strength increases, which behavior is similar as those predicted by the traditional PB equation (without size effect) and by the uniform size-modified Poisson-Boltzmann equation. (3) Nonequilibrium SMPNP simulations of ion permeation through a gramicidin A channel show that the ionic size effects lead to reduced ion current inside the channel compared with the results

  19. Using the ratio of means as the effect size measure in combining results of microarray experiments

    Directory of Open Access Journals (Sweden)

    Greenwood Celia MT

    2009-11-01

    Full Text Available Abstract Background Development of efficient analytic methodologies for combining microarray results is a major challenge in gene expression analysis. The widely used effect size models are thought to provide an efficient modeling framework for this purpose, where the measures of association for each study and each gene are combined, weighted by the standard errors. A significant disadvantage of this strategy is that the quality of different data sets may be highly variable, but this information is usually neglected during the integration. Moreover, it is widely known that the estimated standard deviations are probably unstable in the commonly used effect size measures (such as standardized mean difference when sample sizes in each group are small. Results We propose a re-parameterization of the traditional mean difference based effect measure by using the log ratio of means as an effect size measure for each gene in each study. The estimated effect sizes for all studies were then combined under two modeling frameworks: the quality-unweighted random effects models and the quality-weighted random effects models. We defined the quality measure as a function of the detection p-value, which indicates whether a transcript is reliably detected or not on the Affymetrix gene chip. The new effect size measure is evaluated and compared under the quality-weighted and quality-unweighted data integration frameworks using simulated data sets, and also in several data sets of prostate cancer patients and controls. We focus on identifying differentially expressed biomarkers for prediction of cancer outcomes. Conclusion Our results show that the proposed effect size measure (log ratio of means has better power to identify differentially expressed genes, and that the detected genes have better performance in predicting cancer outcomes than the commonly used effect size measure, the standardized mean difference (SMD, under both quality-weighted and quality

  20. Effect of sodium citrate on preparation of nano-sized cobalt particles by organic colloidal process

    Institute of Scientific and Technical Information of China (English)

    Huaping ZHU; Hao LI; Huiyu SONG; Shijun LIAO

    2009-01-01

    Nano-sized cobalt particles with the diameter of 2 nm were prepared via an organic colloidal process with sodium formate, ethylene glycol and sodium citrate as the reducing agent, the solvent and the complexing agent, respectively. The effects of sodium citrate on the yield, crystal structure, particle size and size distribution of the prepared nano-sized cobalt particles were then investigated. The results show that the average particle diameter decreases from 200 nm to 2 nm when the molar ratio of sodium citrate to cobalt chloride changes from 0 to 6. Furthermore, sodium citrate plays a crucial role in the controlling of size distribution of the nano-sized particles. The size distribution of the particle without sodium citrate addition is in range from tens of nanometers to 300 or 400 nm, while that with sodium citrate addition is limited in the range of (2±0.25) nm. Moreover, it is found that the addition of sodium citrate as a complex agent could decrease the yield of the nano-sized cobalt particle.

  1. Hysteretic sediment fluxes in rainfall-driven soil erosion: Particle size effects

    Science.gov (United States)

    Cheraghi, Mohsen; Jomaa, Seifeddine; Sander, Graham C.; Barry, D. A.

    2016-11-01

    A detailed laboratory study was conducted to examine the effects of particle size on hysteretic sediment transport under time-varying rainfall. A rainfall pattern composed of seven sequential stepwise varying rainfall intensities (30, 37.5, 45, 60, 45, 37.5, and 30 mm h-1), each of 20 min duration, was applied to a 5 m × 2 m soil erosion flume. The soil in the flume was initially dried, ploughed to a depth of 20 cm and had a mechanically smoothed surface. Flow rates and sediment concentration data for seven particle size classes (1000 µm) were measured in the flume effluent. Clockwise hysteresis loops in the sediment concentration versus discharge curves were measured for the total eroded soil and the finer particle sizes (erosion model agreed well with the experimental data for the total eroded soil and for the finer particle size classes (up to 50 µm). For the larger particle size classes, the model provided reasonable qualitative agreement with the measurements although the fit was poor for the largest size class (>1000 µm). Overall, it is found that hysteresis varies amongst particle sizes and that the predictions of the HR model are consistent with hysteretic behavior of different sediment size classes.

  2. Effect the Grain Size on the Polymer Matrix Composites Reinforced by Reenia Particles

    Directory of Open Access Journals (Sweden)

    Kdhim khaion kahlol

    2013-01-01

    Full Text Available Synthetic polymers such as polyurethane are used widely in the field of biomedical applications such as implants or part of implant systems.This paper focuses on the preparation of base polymer matrix composite materials by (Hand Lay-Up method, and studying the effect of selected grain size (32, 53, 63, 75, and 90 µm of (Reenia particles on some properties of the prepared composite.Mechanical tests were used to evaluate the prepared system (Tensile, Compression, Impact, and Hardness tests, and a physical test of (Water absorption %, and all tests were accomplished at room temperature.Where results showed tensile test (maximum tensile strength and modulus of elasticity high at small grain size while the percentage of elongation decreased with increasing size. As the compressive strength increased with small grain size. And also the values of hardness and fracture energy affected by particle size where the hardness and fracture energy increased at small particles size of compared to larger particles size. While the percentage of water absorption increased at large particle size.In general the results showed clear improvement in properties and maximum values which get it of tensile strength, Modulus of elasticity, elongation percentage, compression strength, fracture energy, hardness and water absorption were as follows ((34.8 MPa, (10%, (268 N/mm2, ( 54.2 MPa,( o.408 J, (78.9 Shor (D, (0.2668 % at using (32µm except water absorption was at (90µm .

  3. A study on geometry effect of transmission coil for micro size magnetic induction coil

    Science.gov (United States)

    Lee, Kyung Hwa; Jun, Byoung Ok; Kim, Seunguk; Lee, Gwang Jun; Ryu, Mingyu; Choi, Ji-Woong; Jang, Jae Eun

    2016-05-01

    The effects of transmission (Tx) coil structure have been studied for micro-size magnetic induction coil. The size of the receiving (Rx) coil should be shrunk to the micrometer level for the various new applications such as micro-robot and wireless body implanted devices. In case of the macro-scale magnetic induction coil, the power transmission efficiency is generally considered to be higher as the inductance of the transmission coil became larger; however, the large size difference between macro-size Tx coil and micro-size Rx coil can decrease the power transmission efficiency due to the difference of resonance frequency. Here, we study a correlation of the power transmission with the size and distance between the macro-size Tx and micro-size Rx coils using magnetic induction technique. The maximum power efficiency was 0.28/0.23/0.13/0.12% at the distance of 0.3/1/3/5 cm between Rx and Tx coil. In addition, more efficient wireless power transferring method is suggested with a floating coil for the body implantable devices. The voltage output increased up to 5.4 mV than the original one Tx coil system. The results demonstrated the foundational wireless power transferring system with enhanced power efficiency.

  4. Effect of pressure and fat content on particle sizes in microfluidized milk.

    Science.gov (United States)

    Olson, D W; White, C H; Richter, R L

    2004-10-01

    Average diameters and particle size distributions in fluid milks with different fat contents and subjected to various homogenization pressures with a "microfluidizer" were evaluated. Skim, 2%, and whole milks were microfluidized at 50, 100, 150, and 200 MPa. Cream containing 41% milk fat was microfluidized at 50, 100, and 150 MPa. Particle sizes were determined by laser light scattering. As microfluidization pressure was increased from 50 to 100 MPa, particle sizes in skim, 2%, and whole milks decreased. Microfluidization at pressures greater than 100 MPa had little additional effect on reducing the particle sizes in skim and 2% milks compared with microfluidization at 100 MPa, but the particle sizes in whole milk increased as the microfluidization pressure was increased from 100 to 200 MPa due to formation of homogenization clusters. The particle sizes in cream increased as the microfluidization pressure was increased from 50 to 150 MPa. When the microfluidization pressure was held constant, the particle sizes increased as the milk fat concentration was increased. The coefficients of variations of the volume-weighted particle size distributions for cream were higher than for skim, 2%, and whole milks. Larger "big" particles and smaller "small" particles were formed in whole milk after microfluidization at 200 MPa than at 100 MPa. Although microfluidization can be used to produce small particles in skim, 2%, and whole milks, a higher than optimum pressure (above 100 MPa) applied to whole milk will not lead to the minimum d(43) (volume-weighted average diameter) due to formation of clusters.

  5. The neural bases of the multiplication problem-size effect across countries

    Directory of Open Access Journals (Sweden)

    Jérôme ePrado

    2013-05-01

    Full Text Available Multiplication problems involving large numbers (e.g., 9x8 are more difficult to solve than problems involving small numbers (e.g., 2x3. Behavioral research indicates that this problem-size effect might be due to different factors across countries and educational systems. However, there is no neuroimaging evidence supporting this hypothesis. Here, we compared the neural correlates of the multiplication problem-size effect in adults educated in China and the United States. We found a greater neural problem-size effect in Chinese than American participants in bilateral superior temporal regions associated with phonological processing. However, we found a greater neural problem-size effect in American than Chinese participants in right intra-parietal sulcus associated with calculation procedures. Therefore, while the multiplication problem-size effect might be a verbal retrieval effect in Chinese as compared to American participants, it may instead stem from the use of calculation procedures in American as compared to Chinese participants. Our results indicate that differences in educational practices might affect the neural bases of symbolic arithmetic.

  6. The Effects of Grain Size and Temperature Distributions on the Formation of Interstellar Ice Mantles

    CERN Document Server

    Pauly, Tyler

    2015-01-01

    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 on 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 ...

  7. Thermomagnetic behavior of magnetic susceptibility – heating rate and sample size effects

    Directory of Open Access Journals (Sweden)

    Diana eJordanova

    2016-01-01

    Full Text Available Thermomagnetic analysis of magnetic susceptibility k(T was carried out for a number of natural powder materials from soils, baked clay and anthropogenic dust samples using fast (11oC/min and slow (6.5oC/min heating rates available in the furnace of Kappabridge KLY2 (Agico. Based on the additional data for mineralogy, grain size and magnetic properties of the studied samples, behaviour of k(T cycles and the observed differences in the curves for fast and slow heating rate are interpreted in terms of mineralogical transformations and Curie temperatures (Tc. The effect of different sample size is also explored, using large volume and small volume of powder material. It is found that soil samples show enhanced information on mineralogical transformations and appearance of new strongly magnetic phases when using fast heating rate and large sample size. This approach moves the transformation at higher temperature, but enhances the amplitude of the signal of newly created phase. Large sample size gives prevalence of the local micro- environment, created by evolving gases, released during transformations. The example from archeological brick reveals the effect of different sample sizes on the observed Curie temperatures on heating and cooling curves, when the magnetic carrier is substituted magnetite (Mn0.2Fe2.70O4. Large sample size leads to bigger differences in Tcs on heating and cooling, while small sample size results in similar Tcs for both heating rates.

  8. Manifestation of unusual size effects in granular thin films prepared by pulsed laser deposition

    Science.gov (United States)

    Sergeenkov, S.; Cichetto, L.; Diaz, J. C. C. A.; Bastos, W. B.; Longo, E.; Araújo-Moreira, F. M.

    2016-11-01

    We demonstrate manifestation of some rather unusual size effects in granular thin films prepared by a pulsed laser deposition technique. We observed that the temperature dependence of resistivity ρ(T) notably depends on the relation between the grain size Rg and the film thickness d. Namely, more granular LaNiO3 thin films (with small values of Rg) grown on LaAlO3 substrate are found to follow a universal ρ(T) ∝T 3 / 2 law for all the measured temperatures. While less granular thin films (with larger values of Rg), exhibit a more complicated behavior accompanied by a clear-cut crossover (around Tcr = 200 K), from ρ(T) ∝T 3 / 2 (for 20 K temperature size effects (when an average grain size Rg becomes comparable with the thermal de Broglie wavelength Λ) leading to the crossover temperature Tcr ∝(d /Rg) 2 .

  9. Size effect on solid solid reaction growth between Cu film and Se particles

    Science.gov (United States)

    Kaito, Chihiro; Nonaka, Akira; Kimura, Seiji; Suzuki, Nobuhiko; Saito, Yoshio

    1998-03-01

    A recently developed experimental method of producing a compound by making use of the reaction between thin film and ultrafine particles has been used for copper selenide crystal formation to elucidate the particle size effect on the reaction process. In the case of reaction between Cu film Se particles with size of μm order, CuSe crystals were grown on Se particles by the diffusion of predominantly Cu atoms. In the case of Se particles of the order of 100 nm, amorphous Se particles changed into copper selenide particles by the mutual diffusion of Cu and Se atoms. If the size of Se particles was less than 20 nm, a part of the Cu film changed to copper selenide crystal due to the diffusion of Se atoms to the Cu film. Morphological differences have also been shown and discussed to be the result of the particle size effect.

  10. Effect of particle size on the performance of batchwise centrifugal filtration.

    Science.gov (United States)

    Hwang, K J

    2001-01-01

    The effect of particle size distribution on the performance of batchwise centrifugal filtration is studied. By analyzing the velocity of particles in a filter, a numerical program is designed for simulating the migration and deposition of particles. The particle size distributions and the average specific filtration resistances of cake are then estimated under various rotating speeds of the centrifuge. A large deviation of particle concentration profiles in the filter chamber will occur if the particle size distribution is not taken into consideration. A more heterogeneous cake will form under a lower rotating speed due to the sedimentation effect of particles. The predicted results of particle size distribution and average specific filtration resistance of cake agree well with the available experimental data.

  11. Erosive Augmentation of Solid Propellant Burning Rate: Motor Size Scaling Effect

    Science.gov (United States)

    Strand, L. D.; Cohen, Norman S.

    1990-01-01

    Two different independent variable forms, a difference form and a ratio form, were investigated for correlating the normalized magnitude of the measured erosive burning rate augmentation above the threshold in terms of the amount that the driving parameter (mass flux or Reynolds number) exceeds the threshold value for erosive augmentation at the test condition. The latter was calculated from the previously determined threshold correlation. Either variable form provided a correlation for each of the two motor size data bases individually. However, the data showed a motor size effect, supporting the general observation that the magnitude of erosive burning rate augmentation is reduced for larger rocket motors. For both independent variable forms, the required motor size scaling was attained by including the motor port radius raised to a power in the independent parameter. A boundary layer theory analysis confirmed the experimental finding, but showed that the magnitude of the scale effect is itself dependent upon scale, tending to diminish with increasing motor size.

  12. 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.

  13. Atomistic Study on Size Effects in Thermally Induced Martensitic Phase Transformation of NiTi

    Directory of Open Access Journals (Sweden)

    Sourav Gur

    2016-01-01

    Full Text Available The atomistic study shows strong size effects in thermally induced martensitic phase transformation evolution kinetics of equiatomic NiTi shape memory alloys (SMAs. It is shown that size effects are closely related to the presence of free surfaces; thus, NiTi thin films and nanopillars are studied. Quasi-static molecular dynamics simulations for several cell sizes at various (constant temperatures are performed by employing well-established interatomic potentials for NiTi. The study shows that size plays a crucial role in the evolution of martensite phase fraction and, importantly, can significantly change the phase transformation temperatures, which can be used for the design of NiTi based sensors, actuators, or devices at nano- to microscales. Interestingly, it is found that, at the nanometer scale, Richard’s equation describes very well the martensite phase fraction evolution in NiTi thin films and nanopillars as a function of temperature.

  14. Size and voltage dependence of effective anisotropy in sub-100-nm perpendicular magnetic tunnel junctions

    Science.gov (United States)

    Piotrowski, Stephan K.; Bapna, Mukund; Oberdick, Samuel D.; Majetich, Sara A.; Li, Mingen; Chien, C. L.; Ahmed, Rizvi; Victora, R. H.

    2016-07-01

    Magnetic tunnel junctions with perpendicular magnetic anisotropy are investigated using a conductive atomic force microscope. The 1.23 -nm Co40Fe40B20 recording layer coercivity exhibits a size dependence which suggests single-domain behavior for diameters ≤100 nm. Focusing on devices with diameters smaller than 100 nm, we determine the effect of voltage and size on the effective device anisotropy Keff using two different techniques. Keff is extracted both from distributions of the switching fields of the recording and reference layers and from measurement of thermal fluctuations of the recording layer magnetization when a field close to the switching field is applied. The results from both sets of measurements reveal that Keff increases monotonically with decreasing junction diameter, consistent with the size dependence of the demagnetization energy density. We demonstrate that Keff can be controlled with a voltage down to the smallest size measured, 64 nm.

  15. Effects of particle size on residual stresses of metal matrix composites

    Institute of Scientific and Technical Information of China (English)

    YAN Yi-wu; GENG Lin; LI Ai-bin

    2006-01-01

    A finite element analysis was carried out on the development of residual stresses during the cooling process from the fabrication temperature in the SiCp reinforced Al matrix composites. In the simulation, the two-dimensional and random distribution multi-particle unit cell model and plane strain conditions were used. By incorporating the Taylor-based nonlocal plasticity theory, the effect of particle size on the nature, magnitude and distribution of residual stresses of the composites was studied. The magnitude thermal-stress-induced plastic deformation during cooling was also calculated. The results show similarities in the patterns of thermal residual stress and strain distributions for all ranges of particle size. However, they show differences in magnitude of thermal residual stress as a result of strain gradient effect. The average thermal residual stress increases with decreasing particle size, and the residual plastic strain decreases with decreasing particle size.

  16. Cell size effects for vibration analysis and design of sandwich beams

    Institute of Scientific and Technical Information of China (English)

    Gaoming Dai; Weihong Zhang

    2009-01-01

    In this work, sandwich beams are studied to reveal the underlying size effects of the periodic core cells for the first time within the framework of free vibration analysis of such an advanced lightweight structure. The energy equiv-alence method is formulated as a theoretical approach that takes into account the cell size effect. It is compared with the asymptotic homogenization method and direct finite element method systematically to show their consistence and appli-cability. The accuracy of free vibration responses predicted by the detailed finite element model is used as the standard of comparison. It is shown that the cell size is an important parameter characterizing the cellular core rigidities that influ-ence vibration responses. The homogenization model agrees exactly with the asymptotic solution of the analytical expres-sion of the beam model only whenever the cell size tends to be infinitely small.

  17. Theory of Finite Size Effects for Electronic Quantum Monte Carlo Calculations of Liquids and Solids

    CERN Document Server

    Holzmann, Markus; Morales, Miguel A; Tubmann, Norm M; Ceperley, David M; Pierleoni, Carlo

    2016-01-01

    Concentrating on zero temperature Quantum Monte Carlo calculations of electronic systems, we give a general description of the theory of finite size extrapolations of energies to the thermodynamic limit based on one and two-body correlation functions. We introduce new effective procedures, such as using the potential and wavefunction split-up into long and short range functions to simplify the method and we discuss how to treat backflow wavefunctions. Then we explicitly test the accuracy of our method to correct finite size errors on example hydrogen and helium many-body systems and show that the finite size bias can be drastically reduced for even small systems.

  18. Effects of transverse electron beam size on transition radiation angular distribution

    Energy Technology Data Exchange (ETDEWEB)

    Chiadroni, E., E-mail: enrica.chiadroni@lnf.infn.it [Laboratori Nazionali di Frascati-INFN, via E. Fermi, 40, 00044 Frascati (Italy); Castellano, M. [Laboratori Nazionali di Frascati-INFN, via E. Fermi, 40, 00044 Frascati (Italy); Cianchi, A. [University of Rome ' Tor Vergata' and INFN-Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Honkavaara, K.; Kube, G. [Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607 Hamburg (Germany)

    2012-05-01

    In this paper we consider the effect of the transverse electron beam size on the Optical Transition Radiation (OTR) angular distribution in case of both incoherent and coherent emission. Our results confute the theoretical argumentations presented first in Optics Communications 211, 109 (2002), which predicts a dependence of the incoherent OTR angular distribution on the beam size and emission wavelength. We present here theoretical and experimental data not only to validate the well-established Ginzburg-Frank theory, but also to show the impact of the transverse beam size in case of coherent emission.

  19. Catalytic activity of metallic nanoisland coatings. The influence of size effects on the recombination properties

    Science.gov (United States)

    Tomilina, O. A.; Berzhansky, V. N.; Tomilin, S. V.; Shaposhnikov, A. N.

    2016-08-01

    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.

  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.

  1. Effect of particle size of rice flour on physical and sensory properties of Sel-roti.

    Science.gov (United States)

    Subba, Dilip; Katawal, Surendra Bahadur

    2013-02-01

    Sel-roti is a delicious, deep-fat fried, puffed, ring shaped spongy doughnut like Nepalese indigenous food prepared from the batter of rice flour, ghee and sugar. A study was conducted to determine the effect of particle size of rice flour on bulk density, oil uptake and texture of Sel-roti. Rice was soaked in water and ground with the help of iron mortar and pestle and the flour was analyzed for particle size distribution by using standard sieves and separated into three particle size categories as coarse (> 890 u), medium (120-890 u) and fine ( 0.05) were found.

  2. Modelling the size effect on the melting temperature of nanoparticles, nanowires and nanofilms

    Energy Technology Data Exchange (ETDEWEB)

    Safaei, A [Department of Materials Science and Engineering, Tarbiat Modares University, PO Box 14115-143, Tehran (Iran, Islamic Republic of); Shandiz, M Attarian [Department of Materials Science and Engineering, Tarbiat Modares University, PO Box 14115-143, Tehran (Iran, Islamic Republic of); Sanjabi, S [Department of Materials Science and Engineering, Tarbiat Modares University, PO Box 14115-143, Tehran (Iran, Islamic Republic of); Barber, Z H [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

    2007-05-30

    A model has been developed to account for the dependence of melting temperature on the size of nanosolids (nanoparticles, nanowires and nanofilms). In this model the effect of particle size and shape, lattice and surface packing factor, and the coordination number of the lattice and of the surface crystalline planes are considered. A general equation is proposed, having nonlinear form as a function of the reciprocal of nanosolid size. This model is consistent with reported experimental data for nanoparticles of In and Au, nanowires of Pb and In, and nanofilms of In.

  3. Introducing Meta-Partition, a Useful Methodology to Explore Factors That Influence Ecological Effect Sizes.

    Directory of Open Access Journals (Sweden)

    Zaida Ortega

    Full Text Available The study of the heterogeneity of effect sizes is a key aspect of ecological meta-analyses. Here we propose a meta-analytic methodology to study the influence of moderators in effect sizes by splitting heterogeneity: meta-partition. To introduce this methodology, we performed a meta-partition of published data about the traits that influence species sensitivity to habitat loss, that have been previously analyzed through meta-regression. Thus, here we aim to introduce meta-partition and to make an initial comparison with meta-regression. Meta-partition algorithm consists of three steps. Step 1 is to study the heterogeneity of effect sizes under the assumption of fixed effect model. If heterogeneity is found, we perform step 2, that is, to partition the heterogeneity by the moderator that minimizes heterogeneity within a subset while maximizing heterogeneity between subsets. Then, if effect sizes of the subset are still heterogeneous, we repeat step 1 and 2 until we reach final subsets. Finally, step 3 is to integrate effect sizes of final subsets, with fixed effect model if there is homogeneity, and with random effects model if there is heterogeneity. Results show that meta-partition is valuable to assess the importance of moderators in explaining heterogeneity of effect sizes, as well as to assess the directions of these relations and to detect possible interactions between moderators. With meta-partition we have been able to evaluate the importance of moderators in a more objective way than with meta-regression, and to visualize the complex relations that may exist between them. As ecological issues are often influenced by several factors interacting in complex ways, ranking the importance of possible moderators and detecting possible interactions would make meta-partition a useful exploration tool for ecological meta-analyses.

  4. Effect of the observed pupil size on the amygdala of the beholders

    OpenAIRE

    Amemiya, Shiori; Ohtomo, Kuni

    2011-01-01

    Among a range of cognitive functions of the amygdala, recent studies suggest its involvement in identification of the pupil size. To further address its role, we investigated the response of the amygdala to human and cat faces with varied pupil size, taking into account the effect of the gender and subjective attractiveness ratings. Twenty-seven subjects underwent functional magnetic resonance imaging while viewing faces with large and small pupils. Large pupil faces induced increased activat...

  5. A review of the findings and theories on surface size effects on visual attention.

    Science.gov (United States)

    Peschel, Anne O; Orquin, Jacob L

    2013-12-09

    That surface size has an impact on attention has been well-known in advertising research for almost a century; however, theoretical accounts of this effect have been sparse. To address this issue, we review studies on surface size effects on eye movements in this paper. While most studies find that large objects are more likely to be fixated, receive more fixations, and are fixated faster than small objects, a comprehensive explanation of this effect is still lacking. To bridge the theoretical gap, we relate the findings from this review to three theories of surface size effects suggested in the literature: a linear model based on the assumption of random fixations (Lohse, 1997), a theory of surface size as visual saliency (Pieters etal., 2007), and a theory based on competition for attention (CA; Janiszewski, 1998). We furthermore suggest a fourth model - demand for attention - which we derive from the theory of CA by revising the underlying model assumptions. In order to test the models against each other, we reanalyze data from an eye tracking study investigating surface size and saliency effects on attention. The reanalysis revealed little support for the first three theories while the demand for attention model showed a much better alignment with the data. We conclude that surface size effects may best be explained as an increase in object signal strength which depends on object size, number of objects in the visual scene, and object distance to the center of the scene. Our findings suggest that advertisers should take into account how objects in the visual scene interact in order to optimize attention to, for instance, brands and logos.

  6. A review of the findings and theories on surface size effects on visual attention

    Directory of Open Access Journals (Sweden)

    Anne Odile Peschel

    2013-12-01

    Full Text Available That surface size has an impact on attention has been well-known in advertising research for almost a century; however, theoretical accounts of this effect have been sparse. To address this issue, we review studies on surface size effects on eye movements in this paper. While most studies find that large objects are more likely to be fixated, receive more fixations, and are fixated faster than small objects, a comprehensive explanation of this effect is still lacking. To bridge the theoretical gap, we relate the findings from this review to three theories of surface size effects suggested in the literature: a linear model based on the assumption of random fixations (Lohse, 1997, a theory of surface size as visual saliency (Pieters et al., 2007, and a theory based on competition for attention (Janiszewski, 1998. We furthermore suggest a fourth model – demand for attention –which we derive from the theory of competition for attention by revising the underlying model assumptions. In order to test the models against each other, we reanalyse data from an eye tracking study investigating surface size and saliency effects on attention. The reanalysis revealed little support for the first three theories while the demand for attention model showed a much better alignment with the data. We conclude that surface size effects may best be explained as an increase in object signal strength which depends on object size, number of objects in the visual scene, and object distance to the centre of the scene. Our findings suggest that advertisers should take into account how objects in the visual scene interact in order to optimize attention to, for instance, brands and logos.

  7. Assessing effective population size, coancestry and inbreeding effects on litter size using the pedigree and SNP data in closed lines of the Iberian pig breed.

    Science.gov (United States)

    Silió, L; Barragán, C; Fernández, A I; García-Casco, J; Rodríguez, M C

    2016-04-01

    The complete pedigree of two closed Iberian pig lines (Gamito and Torbiscal), with 798 and 4077 reproducers, has been used to measure the evolution of coancestry (f) and inbreeding (F) for autosomal and X-linked genes along 16 and 28 respective equivalent discrete generations. At the last generation, the mean values of each line were f = 0.41 and 0.22, F = 0.35 and 0.18, fX  = 0.46 and 0.22 and FX  = 0.47 and 0.19, respectively. Other calculated parameters were the effective number of founders (final values, 6.8 and 35.2) and non-founders (1.5 and 2.4), founder genome equivalents (1.2 and 2.3) and effective population size (16.0 and 57.7). Measures of Torbiscal effective size based on rates of coancestry (66.1), inbreeding (65.0) and linkage disequilibrium (71.0) were estimated from whole-genome SNP genotyping data. Values of new and old inbreeding and their respective rates by generation were computed to detect purging effects of natural selection. The analysis of 6854 Torbiscal litters showed significant negative impacts of new and fast inbreeding on litter size, as expected from the purging hypothesis: -0.20 born piglets per litter by a 10% of new inbreeding, and -0.03 and -0.02 piglets by 1% of total and new inbreeding rates, respectively. The analysis performed on 1274 litters of the Gamito line failed to show purging effects. The only significant results were reductions in -0.91 and -0.17 piglets by a 10% of old and X-linked genes inbreeding, respectively. These results may be useful for some practical issues in conservation programs of farm or captive wild animals. © 2015 Blackwell Verlag GmbH.

  8. Accuracy of effect size estimates from published psychological experiments involving multiple trials.

    Science.gov (United States)

    Brand, Andrew; Bradley, M T; Best, Lisa A; Stoica, George

    2011-01-01

    The reporting of exaggerated effect size estimates may occur either through researchers accepting statistically significant results when power is inadequate and/or from repeated measures approaches aggregating, averaging multiple items, or multiple trials. Monte-Carlo simulations with input of a small, medium, or large effect size were conducted on multiple items or trials that were either averaged or aggregated to create a single dependent measure. Alpha was set at the .05 level, and the trials were assessed over item or trial correlations ranging from 0 to 1. Simulations showed a large increase in observed effect size averages and the power to accept these estimates as statistically significant increased over numbers of trials or items. Overestimation effects were mitigated as correlations between trials increased but still remained substantial in some cases. The implications of these findings for meta-analyses and different research scenarios are discussed.

  9. Finite nuclear size corrections to the recoil effect in hydrogenlike ions

    CERN Document Server

    Aleksandrov, I A; Glazov, D A; Shabaev, V M

    2014-01-01

    The finite nuclear size corrections to the relativistic recoil effect in H-like ions are calculated within the Breit approximation. The calculations are performed for the $1s$, $2s$, and $2p_{1/2}$ states in the range $Z =$ 1-110. The obtained results are compared with previous evaluations of this effect. It is found that for heavy ions the previously neglected corrections amount to about 20% of the total nuclear size contribution to the recoil effect calculated within the Breit approximation.

  10. Are larger effect sizes in experimental studies good predictors of higher citation rates?

    DEFF Research Database (Denmark)

    Schneider, Jesper Wiborg; Henriksen, Dorte

    2013-01-01

    Effect sizes are perhaps the most important quantitative information in statistical inferential studies. Recently, the hypothesis that rational citation behaviour in general ought to give credit to studies that successfully apply a treatment and detect greater effects, resulting in such studies...... areas and with a more credible model selection procedure. Using meta-analyses, we identify comparable individual experimental studies (n=259) from five different research specialties. Effect sizes are compared to the citation rates of the individual studies and impact factors for the journals where...

  11. Effect of graphene oxide sheet size on the curing kinetics and thermal stability of epoxy resins

    Science.gov (United States)

    Wang, Xiao; Jin, Jie; Song, Mo; Lin, Yue

    2016-10-01

    This work revealed the influences of graphene oxide (GO) sheet size on the curing kinetics and thermal stability of epoxy resins. A series of GO/epoxy nanocomposites were prepared by the incorporation of three different sized GO sheets, namely GO-1, GO-2 and GO-3, the average size of which was 10.79 μm, 1.72 μm and 0.70 μm, respectively. The morphologies of the nanocomposites were observed by field emission gun scanning electron microscope. The dispersion quality of each sized GO was comparable in the epoxy matrix. The curing kinetics was investigated by means of differential scanning calorimetry and analyzed based on kinetics model. Addition of a small amount of GO (0.1 wt%) exhibited strong catalytic effect on the curing reaction of epoxy resin. The activation energy was reduced by 18.9%, 28.8% and 14.6% with addition of GO-1, GO-2 and GO-3, respectively. GO-2 with medium size (1.72 μm) showed the most effective catalysis on the cure. The thermal stability of the cured resins was evaluated based on thermogravimetric analysis. GO/epoxy nanocomposites showed improved thermal stability in the range of 420 °C-500 °C, compared with the pure resin. A ˜ 4% more residue was obtained in each of the incorporated system. The variations of GO sheet size did not influence the enhancement effect on the thermal stability.

  12. Comprehensive size effect on PbSe quantum dot-doped liquid-core optical fiber

    Science.gov (United States)

    Zhang, Lei; Zhang, Bing; Ning, Lina; Li, Shuai; Zheng, Youjin

    2017-01-01

    We have theoretically studied a comprehensive size effect on the spectra of PbSe quantum dot (QD)-doped liquid-core optical fiber, including PbSe QD's particle size and particle number effect, and fiber length and fiber diameter effect. The doping concentration, pump intensity and wavelength were fixed at proper values for comparison. The red shift of emission spectral peak increased with QD diameter, QD number, fiber length and fiber diameter, and reached up to saturation with increasingly QD number which was explained in detail. The evolutions of spectral intensity with the four size parameters were gained, and the related "optimal" (under the certain other parameters) fiber length, diameter and QD number were observed for PbSe QDs of different size as the dopant. Furthermore, each kind of the "optimal" value changed with the other three size parameters. These four size parameters restricted each other, and affected the spectral features together. The calculating results fitted well to the experimental data. This research might be a theoretical basis in the design of optical fiber-based device.

  13. The Effect of Solid Constituent Particle Size Distributions on TP-H1148 Propellant Slag

    Science.gov (United States)

    May, Douglas H.; Miles, William L.; Taylor, David S.; Rackham, Jon L.

    1997-01-01

    Special aluminum and ammonium perchlorate (AP) particle size distributions were prepared for a matrix of five-inch diameter, center-perforated (CP) motor tests to measure the aluminum oxide slag response in Space Shuttle Reusable Solid Rocket Motor (RSRM) propellant. Previous tests of TP-H1148 propellant in five-inch CP spin motors have shown a correlation between aluminum particle size and generated slag. The motors for this study were cast from thirteen five-gallon propellant mixes which used five particle size levels of aluminum powder, five of unground AP and three of ground AP. Aluminum had the greatest effect on slag formation, the more coarse fractions causing greater slag quantities and larger slag particles. Unground AP had about half the effect of aluminum with the coarser fractions again producing more and larger sized slag particles. The variation in ground AP did not have a significant effect on slag formation. Quench bomb tests showed the same trends as the spin motors, that is, larger aluminum and AP particle size distributions generated larger slag particles leaving the propellant surface. Cured propellant mechanical properties were also impacted by particle size variation.

  14. Two-phase equilibrium states in individual Cu–Ni nanoparticles: size, depletion and hysteresis effects

    Directory of Open Access Journals (Sweden)

    Aram S. Shirinyan

    2015-08-01

    Full Text Available In isolated bimetallic nanoscale systems the limit amount of matter and surface-induced size effects can change the thermodynamics of first-order phase transformation. In this paper we present theoretical modification of Gibbs free energy concept describing first-order phase transformation of binary alloyed nanoparticles taking into account size effects as well as depletion and hysteresis effects. In such a way the hysteresis in a form of nonsymmetry for forth and back transforming paths takes place; compositional splitting and the loops-like splitted path on the size dependent temperature–composition phase diagram occur. Our calculations for individual Cu–Ni nanoparticle show that one must differentiate the solubility curves and the equilibrium loops (discussed here in term of solidification and melting loops. For the first time we have calculated and present here on the temperature–composition phase diagram the nanomelting loop at the size of 80 nm and the nanosolidification loop at the size of 25 nm for an individual Cu–Ni nanoparticle. So we observe the difference between the size-dependent phase diagram and solubility diagram, between two-phase equilibrium curves and solubility curves; also intersection of nanoliquidus and nanosolidus is available. These findings lead to the necessity to reconsider such basic concepts in materials science as phase diagram and solubility diagram.

  15. Two-phase equilibrium states in individual Cu-Ni nanoparticles: size, depletion and hysteresis effects.

    Science.gov (United States)

    Shirinyan, Aram S

    2015-01-01

    In isolated bimetallic nanoscale systems the limit amount of matter and surface-induced size effects can change the thermodynamics of first-order phase transformation. In this paper we present theoretical modification of Gibbs free energy concept describing first-order phase transformation of binary alloyed nanoparticles taking into account size effects as well as depletion and hysteresis effects. In such a way the hysteresis in a form of nonsymmetry for forth and back transforming paths takes place; compositional splitting and the loops-like splitted path on the size dependent temperature-composition phase diagram occur. Our calculations for individual Cu-Ni nanoparticle show that one must differentiate the solubility curves and the equilibrium loops (discussed here in term of solidification and melting loops). For the first time we have calculated and present here on the temperature-composition phase diagram the nanomelting loop at the size of 80 nm and the nanosolidification loop at the size of 25 nm for an individual Cu-Ni nanoparticle. So we observe the difference between the size-dependent phase diagram and solubility diagram, between two-phase equilibrium curves and solubility curves; also intersection of nanoliquidus and nanosolidus is available. These findings lead to the necessity to reconsider such basic concepts in materials science as phase diagram and solubility diagram.

  16. Atomization method for verifying size effects of inhalable particles on lung damage of mice.

    Science.gov (United States)

    Tao, Chen; Tang, Yue; Zhang, Lan; Tian, Yonggang; Zhang, Yingmei

    2017-02-01

    To explore the size effects of inhalable particles on lung damage, aqueous aerosol containing cadmium was studied as a model to design a new type of two-stage atomization device that was composed of two adjustable parts with electronic ultrasonic atomization and pneumatic atomization. The working parameters and effectiveness of this device were tested with H2O atomization and CdCl2 inhalation, respectively. By gravimetrically detecting the mass concentrations of PM2.5 and PM10 and analysing the particle size with a laser sensor, we confirmed the particle size distribution of the aqueous aerosol produced by the new device under different working conditions. Then, we conducted experiments in male Kunming mice that inhaled CdCl2 to determine the size effects of inhalable particles on lung damage and to confirm the effectiveness of the device. The new device could effectively control the particle size in the aqueous aerosol. The inhaled CdCl2 entered and injured the lungs of the mice by causing tissue damage, oxidative stress, increasing endoplasmic reticulum stress and triggering an inflammatory response, which might be related to where the particles deposited. The smaller particles in the aqueous aerosol atomized by the new two-stage atomization device deposited deeper into lung causing more damage. This device could provide a new method for animal experiments involving inhalation with water-soluble toxins.

  17. Experimental study on size-dependency of effective permittivity of particle-gas mixture with agglomeration

    Institute of Scientific and Technical Information of China (English)

    Li Xiaomin; Xu Lijun; Li Songyun

    2007-01-01

    The effective medium approximation (EMA) theory is the basis of a capacitance sensor used for concentration measurement of a particulate solid flow, its measurement result is independent on particle size. In existence of particle agglomeration or aggradation, however, it is found that the effective permittivity of a gas/solid mixture is dependent on particle size. In this paper, a parallel plate, differential capacitance sensor is utilized to investigate the influence of particle size on the effective permittivity of the mixture in such a case. Static experiments using three materials including glass, limestone and quartz particles were carried out in an off-line manner. The volume fraction of particles being tested ranged from 20×10-6 to 600×10-6, while the particle size was between 3 and 100 μm. Experimental results show that the effective permittivity of a particle-gas mixture with particle agglomeration is larger than that predicted by EMA and the smaller the particle size, the larger the effective permittivity. The experiment process and analysis results are discussed in detail in the paper.

  18. Effects of Wheel and Hand-Rim Size on Submaximal Propulsion in Wheelchair Athletes

    NARCIS (Netherlands)

    Mason, Barry S.; Van der Woude, Lucas H. V.; Tolfrey, Keith; Lenton, John P.; Goosey-Tolfrey, Victoria L.

    MASON, B. S., L. H. V. VAN DER WOUDE, K. TOLFREY, J. P. LENTON, and V. L. GOOSEY-TOLFREY. Effects of Wheel and Hand-Rim Size on Submaximal Propulsion in Wheelchair Athletes. Med. Sci. Sports Exerc., Vol. 44, No. 1, pp. 126-134, 2012. Purpose: This study aimed to investigate the effects of fixed gear

  19. The Effect of "Origami" Practice on Size Comparison Strategy among Young Japanese and American Children.

    Science.gov (United States)

    Yuzawa, Masamichi; Bart, William M.; Kinne, Lenore J.; Sukemune, Seisoh; Kataoka, Minako

    1999-01-01

    Explored the effect of folding traditional origami forms on size comparison strategies among 4- to 6-year-old Japanese and American children. Found that girls in particular improved superimposition skills through practice, and children's use of superimposition strategies rather than less effective strategies also increased. (JPB)

  20. The long-term effect of the timing of fertility decline on population size

    NARCIS (Netherlands)

    O'Neill, BC; Scherbov, S; Lutz, W

    1999-01-01

    Existing long-range population projections imply that the timing of the fertility transition has a relatively unimportant effect on long-term population size when compared with the impact of the level at which fertility is assumed eventually to stabilize. However, this note shows that the effect of