Estimating the efficacy of Alcoholics Anonymous without self-selection bias: an instrumental variables re-analysis of randomized clinical trials.

PubMed

Humphreys, Keith; Blodgett, Janet C; Wagner, Todd H

2014-11-01

Observational studies of Alcoholics Anonymous' (AA) effectiveness are vulnerable to self-selection bias because individuals choose whether or not to attend AA. The present study, therefore, employed an innovative statistical technique to derive a selection bias-free estimate of AA's impact. Six data sets from 5 National Institutes of Health-funded randomized trials (1 with 2 independent parallel arms) of AA facilitation interventions were analyzed using instrumental variables models. Alcohol-dependent individuals in one of the data sets (n = 774) were analyzed separately from the rest of sample (n = 1,582 individuals pooled from 5 data sets) because of heterogeneity in sample parameters. Randomization itself was used as the instrumental variable. Randomization was a good instrument in both samples, effectively predicting increased AA attendance that could not be attributed to self-selection. In 5 of the 6 data sets, which were pooled for analysis, increased AA attendance that was attributable to randomization (i.e., free of self-selection bias) was effective at increasing days of abstinence at 3-month (B = 0.38, p = 0.001) and 15-month (B = 0.42, p = 0.04) follow-up. However, in the remaining data set, in which preexisting AA attendance was much higher, further increases in AA involvement caused by the randomly assigned facilitation intervention did not affect drinking outcome. For most individuals seeking help for alcohol problems, increasing AA attendance leads to short- and long-term decreases in alcohol consumption that cannot be attributed to self-selection. However, for populations with high preexisting AA involvement, further increases in AA attendance may have little impact. Copyright © 2014 by the Research Society on Alcoholism.

Selective decontamination of the digestive tract in gastrointestinal surgery: useful in infection prevention? A systematic review.

PubMed

Abis, Gabor S A; Stockmann, Hein B A C; van Egmond, Marjolein; Bonjer, Hendrik J; Vandenbroucke-Grauls, Christina M J E; Oosterling, Steven J

2013-12-01

Gastrointestinal surgery is associated with a high incidence of infectious complications. Selective decontamination of the digestive tract is an antimicrobial prophylaxis regimen that aims to eradicate gastrointestinal carriage of potentially pathogenic microorganisms and represents an adjunct to regular prophylaxis in surgery. Relevant studies were identified using bibliographic searches of MEDLINE, EMBASE, and the Cochrane database (period from 1970 to November 1, 2012). Only studies investigating selective decontamination of the digestive tract in gastrointestinal surgery were included. Two randomized clinical trials and one retrospective case-control trial showed significant benefit in terms of infectious complications and anastomotic leakage in colorectal surgery. Two randomized controlled trials in esophageal surgery and two randomized clinical trials in gastric surgery reported lower levels of infectious complications. Selective decontamination of the digestive tract reduces infections following esophageal, gastric, and colorectal surgeries and also appears to have beneficial effects on anastomotic leakage in colorectal surgery. We believe these results provide the basis for a large multicenter prospective study to investigate the role of selective decontamination of the digestive tract in colorectal surgery.

The Effect of CAI on Reading Achievement.

ERIC Educational Resources Information Center

Hardman, Regina

A study determined whether computer assisted instruction (CAI) had an effect on students' reading achievement. Subjects were 21 randomly selected fourth-grade students at D. S. Wentworth Elementary School on the south side of Chicago in a low-income neighborhood who received a year's exposure to a CAI program, and 21 randomly selected students at…

Site Selection in Experiments: A Follow-Up Evaluation of Site Recruitment in Two Scale-Up Studies

ERIC Educational Resources Information Center

Tipton, Elizabeth; Fellers, Lauren; Caverly, Sarah; Vaden-Kiernan, Michael; Borman, Geoffrey; Sullivan, Kate; Ruiz de Castillo, Veronica

2015-01-01

Randomized experiments are commonly used to evaluate if particular interventions improve student achievement. While these experiments can establish that a treatment actually "causes" changes, typically the participants are not randomly selected from a well-defined population and therefore the results do not readily generalize. Three…

Issues Relating to Selective Reporting When Including Non-Randomized Studies in Systematic Reviews on the Effects of Healthcare Interventions

ERIC Educational Resources Information Center

Norris, Susan L.; Moher, David; Reeves, Barnaby C.; Shea, Beverley; Loke, Yoon; Garner, Sarah; Anderson, Laurie; Tugwell, Peter; Wells, George

2013-01-01

Background: Selective outcome and analysis reporting (SOR and SAR) occur when only a subset of outcomes measured and analyzed in a study is fully reported, and are an important source of potential bias. Key methodological issues: We describe what is known about the prevalence and effects of SOR and SAR in both randomized controlled trials (RCTs)…

Evolution in fluctuating environments: decomposing selection into additive components of the Robertson-Price equation.

PubMed

Engen, Steinar; Saether, Bernt-Erik

2014-03-01

We analyze the stochastic components of the Robertson-Price equation for the evolution of quantitative characters that enables decomposition of the selection differential into components due to demographic and environmental stochasticity. We show how these two types of stochasticity affect the evolution of multivariate quantitative characters by defining demographic and environmental variances as components of individual fitness. The exact covariance formula for selection is decomposed into three components, the deterministic mean value, as well as stochastic demographic and environmental components. We show that demographic and environmental stochasticity generate random genetic drift and fluctuating selection, respectively. This provides a common theoretical framework for linking ecological and evolutionary processes. Demographic stochasticity can cause random variation in selection differentials independent of fluctuating selection caused by environmental variation. We use this model of selection to illustrate that the effect on the expected selection differential of random variation in individual fitness is dependent on population size, and that the strength of fluctuating selection is affected by how environmental variation affects the covariance in Malthusian fitness between individuals with different phenotypes. Thus, our approach enables us to partition out the effects of fluctuating selection from the effects of selection due to random variation in individual fitness caused by demographic stochasticity. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Wide brick tunnel randomization - an unequal allocation procedure that limits the imbalance in treatment totals.

PubMed

Kuznetsova, Olga M; Tymofyeyev, Yevgen

2014-04-30

In open-label studies, partial predictability of permuted block randomization provides potential for selection bias. To lessen the selection bias in two-arm studies with equal allocation, a number of allocation procedures that limit the imbalance in treatment totals at a pre-specified level but do not require the exact balance at the ends of the blocks were developed. In studies with unequal allocation, however, the task of designing a randomization procedure that sets a pre-specified limit on imbalance in group totals is not resolved. Existing allocation procedures either do not preserve the allocation ratio at every allocation or do not include all allocation sequences that comply with the pre-specified imbalance threshold. Kuznetsova and Tymofyeyev described the brick tunnel randomization for studies with unequal allocation that preserves the allocation ratio at every step and, in the two-arm case, includes all sequences that satisfy the smallest possible imbalance threshold. This article introduces wide brick tunnel randomization for studies with unequal allocation that allows all allocation sequences with imbalance not exceeding any pre-specified threshold while preserving the allocation ratio at every step. In open-label studies, allowing a larger imbalance in treatment totals lowers selection bias because of the predictability of treatment assignments. The applications of the technique in two-arm and multi-arm open-label studies with unequal allocation are described. Copyright © 2013 John Wiley & Sons, Ltd.

Changing Friend Selection in Middle School: A Social Network Analysis of a Randomized Intervention Study Designed to Prevent Adolescent Problem Behavior.

PubMed

DeLay, Dawn; Ha, Thao; Van Ryzin, Mark; Winter, Charlotte; Dishion, Thomas J

2016-04-01

Adolescent friendships that promote problem behavior are often chosen in middle school. The current study examines the unintended impact of a randomized school-based intervention on the selection of friends in middle school, as well as on observations of deviant talk with friends 5 years later. Participants included 998 middle school students (526 boys and 472 girls) recruited at the onset of middle school (age 11-12 years) from three public middle schools participating in the Family Check-up model intervention. The current study focuses only on the effects of the SHAPe curriculum-one level of the Family Check-up model-on friendship choices. Participants nominated friends and completed measures of deviant peer affiliation. Approximately half of the sample (n = 500) was randomly assigned to the intervention, and the other half (n = 498) comprised the control group within each school. The results indicate that the SHAPe curriculum affected friend selection within school 1 but not within schools 2 or 3. The effects of friend selection in school 1 translated into reductions in observed deviancy training 5 years later (age 16-17 years). By coupling longitudinal social network analysis with a randomized intervention study, the current findings provide initial evidence that a randomized public middle school intervention can disrupt the formation of deviant peer groups and diminish levels of adolescent deviance 5 years later.

Effect of expanding medicaid for parents on children's health insurance coverage: lessons from the Oregon experiment.

PubMed

DeVoe, Jennifer E; Marino, Miguel; Angier, Heather; O'Malley, Jean P; Crawford, Courtney; Nelson, Christine; Tillotson, Carrie J; Bailey, Steffani R; Gallia, Charles; Gold, Rachel

2015-01-01

In the United States, health insurance is not universal. Observational studies show an association between uninsured parents and children. This association persisted even after expansions in child-only public health insurance. Oregon's randomized Medicaid expansion for adults, known as the Oregon Experiment, created a rare opportunity to assess causality between parent and child coverage. To estimate the effect on a child's health insurance coverage status when (1) a parent randomly gains access to health insurance and (2) a parent obtains coverage. Oregon Experiment randomized natural experiment assessing the results of Oregon's 2008 Medicaid expansion. We used generalized estimating equation models to examine the longitudinal effect of a parent randomly selected to apply for Medicaid on their child's Medicaid or Children's Health Insurance Program (CHIP) coverage (intent-to-treat analyses). We used per-protocol analyses to understand the impact on children's coverage when a parent was randomly selected to apply for and obtained Medicaid. Participants included 14409 children aged 2 to 18 years whose parents participated in the Oregon Experiment. For intent-to-treat analyses, the date a parent was selected to apply for Medicaid was considered the date the child was exposed to the intervention. In per-protocol analyses, exposure was defined as whether a selected parent obtained Medicaid. Children's Medicaid or CHIP coverage, assessed monthly and in 6-month intervals relative to their parent's selection date. In the immediate period after selection, children whose parents were selected to apply significantly increased from 3830 (61.4%) to 4152 (66.6%) compared with a nonsignificant change from 5049 (61.8%) to 5044 (61.7%) for children whose parents were not selected to apply. Children whose parents were randomly selected to apply for Medicaid had 18% higher odds of being covered in the first 6 months after parent's selection compared with children whose parents were not selected (adjusted odds ratio [AOR]=1.18; 95% CI, 1.10-1.27). The effect remained significant during months 7 to 12 (AOR=1.11; 95% CI, 1.03-1.19); months 13 to 18 showed a positive but not significant effect (AOR=1.07; 95% CI, 0.99-1.14). Children whose parents were selected and obtained coverage had more than double the odds of having coverage compared with children whose parents were not selected and did not gain coverage (AOR=2.37; 95% CI, 2.14-2.64). Children's odds of having Medicaid or CHIP coverage increased when their parents were randomly selected to apply for Medicaid. Children whose parents were selected and subsequently obtained coverage benefited most. This study demonstrates a causal link between parents' access to Medicaid coverage and their children's coverage.

Does time-lapse imaging have favorable results for embryo incubation and selection compared with conventional methods in clinical in vitro fertilization? A meta-analysis and systematic review of randomized controlled trials

PubMed Central

Yuan, Jing; Liu, Fenghua

2017-01-01

Objective The present study aimed to undertake a review of available evidence assessing whether time-lapse imaging (TLI) has favorable outcomes for embryo incubation and selection compared with conventional methods in clinical in vitro fertilization (IVF). Methods Using PubMed, EMBASE, Cochrane library and ClinicalTrial.gov up to February 2017 to search for randomized controlled trials (RCTs) comparing TLI versus conventional methods. Both studies randomized women and oocytes were included. For studies randomized women, the primary outcomes were live birth and ongoing pregnancy, the secondary outcomes were clinical pregnancy and miscarriage; for studies randomized oocytes, the primary outcome was blastocyst rate, the secondary outcome was good quality embryo on Day 2/3. Subgroup analysis was conducted based on different incubation and embryo selection between groups. Results Ten RCTs were included, four randomized oocytes and six randomized women. For oocyte-based review, the pool-analysis observed no significant difference between TLI group and control group for blastocyst rate [relative risk (RR) 1.08, 95% CI 0.94–1.25, I2 = 0%, two studies, including 1154 embryos]. The quality of evidence was moderate for all outcomes in oocyte-based review. For woman-based review, only one study provided live birth rate (RR 1,23, 95% CI 1.06–1.44,I2 N/A, one study, including 842 women), the pooled result showed no significant difference in ongoing pregnancy rate (RR 1.04, 95% CI 0.80–1.36, I2 = 59%, four studies, including 1403 women) between two groups. The quality of the evidence was low or very low for all outcomes in woman-based review. Conclusions Currently there is insufficient evidence to support that TLI is superior to conventional methods for human embryo incubation and selection. In consideration of the limitations and flaws of included studies, more well designed RCTs are still in need to comprehensively evaluate the effectiveness of clinical TLI use. PMID:28570713

The Effects of Social Capital Levels in Elementary Schools on Organizational Information Sharing

ERIC Educational Resources Information Center

Ekinci, Abdurrahman

2012-01-01

This study aims to assess the effects of social capital levels at elementary schools on organizational information sharing as reported by teachers. Participants were 267 teachers selected randomly from 16 elementary schools; schools also selected randomly among 42 elementary schools located in the city center of Batman. The data were analyzed by…

Cooperation and charity in spatial public goods game under different strategy update rules

NASA Astrophysics Data System (ADS)

Li, Yixiao; Jin, Xiaogang; Su, Xianchuang; Kong, Fansheng; Peng, Chengbin

2010-03-01

Human cooperation can be influenced by other human behaviors and recent years have witnessed the flourishing of studying the coevolution of cooperation and punishment, yet the common behavior of charity is seldom considered in game-theoretical models. In this article, we investigate the coevolution of altruistic cooperation and egalitarian charity in spatial public goods game, by considering charity as the behavior of reducing inter-individual payoff differences. Our model is that, in each generation of the evolution, individuals play games first and accumulate payoff benefits, and then each egalitarian makes a charity donation by payoff transfer in its neighborhood. To study the individual-level evolutionary dynamics, we adopt different strategy update rules and investigate their effects on charity and cooperation. These rules can be classified into two global rules: random selection rule in which individuals randomly update strategies, and threshold selection rule where only those with payoffs below a threshold update strategies. Simulation results show that random selection enhances the cooperation level, while threshold selection lowers the threshold of the multiplication factor to maintain cooperation. When charity is considered, it is incapable in promoting cooperation under random selection, whereas it promotes cooperation under threshold selection. Interestingly, the evolution of charity strongly depends on the dispersion of payoff acquisitions of the population, which agrees with previous results. Our work may shed light on understanding human egalitarianism.

Effectiveness of a new health care organization model in primary care for chronic cardiovascular disease patients based on a multifactorial intervention: the PROPRESE randomized controlled trial.

PubMed

Orozco-Beltran, Domingo; Ruescas-Escolano, Esther; Navarro-Palazón, Ana Isabel; Cordero, Alberto; Gaubert-Tortosa, María; Navarro-Perez, Jorge; Carratalá-Munuera, Concepción; Pertusa-Martínez, Salvador; Soler-Bahilo, Enrique; Brotons-Muntó, Francisco; Bort-Cubero, Jose; Nuñez-Martinez, Miguel Angel; Bertomeu-Martinez, Vicente; Gil-Guillen, Vicente Francisco

2013-08-02

To evaluate the effectiveness of a new multifactorial intervention to improve health care for chronic ischemic heart disease patients in primary care. The strategy has two components: a) organizational for the patient/professional relationship and b) training for professionals. Experimental study. Randomized clinical trial. Follow-up period: one year. primary care, multicenter (15 health centers). For the intervention group 15 health centers are selected from those participating in ESCARVAL study. Once the center agreed to participate patients are randomly selected from the total amount of patients with ischemic heart disease registered in the electronic health records. For the control group a random sample of patients with ischemic heart disease is selected from all 72 health centers electronic records. This study aims to evaluate the efficacy of a multifactorial intervention strategy involving patients with ischemic heart disease for the improvement of the degree of control of the cardiovascular risk factors and of the quality of life, number of visits, and number of hospitalizations. NCT01826929.

Computerized stratified random site-selection approaches for design of a ground-water-quality sampling network

USGS Publications Warehouse

Scott, J.C.

1990-01-01

Computer software was written to randomly select sites for a ground-water-quality sampling network. The software uses digital cartographic techniques and subroutines from a proprietary geographic information system. The report presents the approaches, computer software, and sample applications. It is often desirable to collect ground-water-quality samples from various areas in a study region that have different values of a spatial characteristic, such as land-use or hydrogeologic setting. A stratified network can be used for testing hypotheses about relations between spatial characteristics and water quality, or for calculating statistical descriptions of water-quality data that account for variations that correspond to the spatial characteristic. In the software described, a study region is subdivided into areal subsets that have a common spatial characteristic to stratify the population into several categories from which sampling sites are selected. Different numbers of sites may be selected from each category of areal subsets. A population of potential sampling sites may be defined by either specifying a fixed population of existing sites, or by preparing an equally spaced population of potential sites. In either case, each site is identified with a single category, depending on the value of the spatial characteristic of the areal subset in which the site is located. Sites are selected from one category at a time. One of two approaches may be used to select sites. Sites may be selected randomly, or the areal subsets in the category can be grouped into cells and sites selected randomly from each cell.

Effects of zinc supplementation on subscales of anorexia in children: A randomized controlled trial.

PubMed

Khademian, Majid; Farhangpajouh, Neda; Shahsanaee, Armindokht; Bahreynian, Maryam; Mirshamsi, Mehran; Kelishadi, Roya

2014-01-01

This study aims to assess the effects of zinc supplementation on improving the appetite and its subscales in children. This study was conducted in 2013 in Isfahan, Iran. It had two phases. At the first step, after validation of the Child Eating Behaviour Questionaire (CEBQ), it was completed for 300 preschool children, who were randomly selected. The second phase was conducted as a randomized controlled trial. Eighty of these children were randomly selected, and were randomly assigned to two groups of equal number receiving zinc (10 mg/day) or placebo for 12 weeks. Overall 77 children completed the trial (39 in the case and 3 in the control group).The results showed that zinc supplement can improve calorie intake in children by affecting some CEBQ subscales like Emotional over Eating and Food Responsible. Zinc supplementation had positive impact in promoting the calorie intake and some subscales of anorexia.

Clinical Trial Registries Are of Minimal Use for Identifying Selective Outcome and Analysis Reporting

ERIC Educational Resources Information Center

Norris, Susan L.; Holmer, Haley K.; Fu, Rongwei; Ogden, Lauren A.; Viswanathan, Meera S.; Abou-Setta, Ahmed M.

2014-01-01

Objective: This study aimed to examine selective outcome reporting (SOR) and selective analysis reporting (SAR) in randomized controlled trials (RCTs) and to explore the usefulness of trial registries for identifying SOR and SAR. Study Design and Setting: We selected one "index outcome" for each of three comparative effectiveness reviews…

Selection dynamic of Escherichia coli host in M13 combinatorial peptide phage display libraries.

PubMed

Zanconato, Stefano; Minervini, Giovanni; Poli, Irene; De Lucrezia, Davide

2011-01-01

Phage display relies on an iterative cycle of selection and amplification of random combinatorial libraries to enrich the initial population of those peptides that satisfy a priori chosen criteria. The effectiveness of any phage display protocol depends directly on library amino acid sequence diversity and the strength of the selection procedure. In this study we monitored the dynamics of the selective pressure exerted by the host organism on a random peptide library in the absence of any additional selection pressure. The results indicate that sequence censorship exerted by Escherichia coli dramatically reduces library diversity and can significantly impair phage display effectiveness.

Effects of prey abundance, distribution, visual contrast and morphology on selection by a pelagic piscivore

USGS Publications Warehouse

Hansen, Adam G.; Beauchamp, David A.

2014-01-01

Most predators eat only a subset of possible prey. However, studies evaluating diet selection rarely measure prey availability in a manner that accounts for temporal–spatial overlap with predators, the sensory mechanisms employed to detect prey, and constraints on prey capture.We evaluated the diet selection of cutthroat trout (Oncorhynchus clarkii) feeding on a diverse planktivore assemblage in Lake Washington to test the hypothesis that the diet selection of piscivores would reflect random (opportunistic) as opposed to non-random (targeted) feeding, after accounting for predator–prey overlap, visual detection and capture constraints.Diets of cutthroat trout were sampled in autumn 2005, when the abundance of transparent, age-0 longfin smelt (Spirinchus thaleichthys) was low, and 2006, when the abundance of smelt was nearly seven times higher. Diet selection was evaluated separately using depth-integrated and depth-specific (accounted for predator–prey overlap) prey abundance. The abundance of different prey was then adjusted for differences in detectability and vulnerability to predation to see whether these factors could explain diet selection.In 2005, cutthroat trout fed non-randomly by selecting against the smaller, transparent age-0 longfin smelt, but for the larger age-1 longfin smelt. After adjusting prey abundance for visual detection and capture, cutthroat trout fed randomly. In 2006, depth-integrated and depth-specific abundance explained the diets of cutthroat trout well, indicating random feeding. Feeding became non-random after adjusting for visual detection and capture. Cutthroat trout selected strongly for age-0 longfin smelt, but against similar sized threespine stickleback (Gasterosteus aculeatus) and larger age-1 longfin smelt in 2006. Overlap with juvenile sockeye salmon (O. nerka) was minimal in both years, and sockeye salmon were rare in the diets of cutthroat trout.The direction of the shift between random and non-random selection depended on the presence of a weak versus a strong year class of age-0 longfin smelt. These fish were easy to catch, but hard to see. When their density was low, poor detection could explain their rarity in the diet. When their density was high, poor detection was compensated by higher encounter rates with cutthroat trout, sufficient to elicit a targeted feeding response. The nature of the feeding selectivity of a predator can be highly dependent on fluctuations in the abundance and suitability of key prey.

Comparative Evaluations of Randomly Selected Four Point-of-Care Glucometer Devices in Addis Ababa, Ethiopia.

PubMed

Wolde, Mistire; Tarekegn, Getahun; Kebede, Tedla

2018-05-01

Point-of-care glucometer (PoCG) devices play a significant role in self-monitoring of the blood sugar level, particularly in the follow-up of high blood sugar therapeutic response. The aim of this study was to evaluate blood glucose test results performed with four randomly selected glucometers on diabetes and control subjects versus standard wet chemistry (hexokinase) methods in Addis Ababa, Ethiopia. A prospective cross-sectional study was conducted on randomly selected 200 study participants (100 participants with diabetes and 100 healthy controls). Four randomly selected PoCG devices (CareSens N, DIAVUE Prudential, On Call Extra, i-QARE DS-W) were evaluated against hexokinase method and ISO 15197:2003 and ISO 15197:2013 standards. The minimum and maximum blood sugar values were recorded by CareSens N (21 mg/dl) and hexokinase method (498.8 mg/dl), respectively. The mean sugar values of all PoCG devices except On Call Extra showed significant differences compared with the reference hexokinase method. Meanwhile, all four PoCG devices had strong positive relationship (>80%) with the reference method (hexokinase). On the other hand, none of the four PoCG devices fulfilled the minimum accuracy measurement set by ISO 15197:2003 and ISO 15197:2013 standards. In addition, the linear regression analysis revealed that all four selected PoCG overestimated the glucose concentrations. The overall evaluation of the selected four PoCG measurements were poorly correlated with standard reference method. Therefore, before introducing PoCG devices to the market, there should be a standardized evaluation platform for validation. Further similar large-scale studies on other PoCG devices also need to be undertaken.

Effect of Expanding Medicaid for Parents on Children’s Health Insurance Coverage

PubMed Central

DeVoe, Jennifer E.; Marino, Miguel; Angier, Heather; O’Malley, Jean P.; Crawford, Courtney; Nelson, Christine; Tillotson, Carrie J.; Bailey, Steffani R.; Gallia, Charles; Gold, Rachel

2016-01-01

IMPORTANCE In the United States, health insurance is not universal. Observational studies show an association between uninsured parents and children. This association persisted even after expansions in child-only public health insurance. Oregon’s randomized Medicaid expansion for adults, known as the Oregon Experiment, created a rare opportunity to assess causality between parent and child coverage. OBJECTIVE To estimate the effect on a child’s health insurance coverage status when (1) a parent randomly gains access to health insurance and (2) a parent obtains coverage. DESIGN, SETTING, AND PARTICIPANTS Oregon Experiment randomized natural experiment assessing the results of Oregon’s 2008 Medicaid expansion. We used generalized estimating equation models to examine the longitudinal effect of a parent randomly selected to apply for Medicaid on their child’s Medicaid or Children’s Health Insurance Program (CHIP) coverage (intent-to-treat analyses). We used per-protocol analyses to understand the impact on children’s coverage when a parent was randomly selected to apply for and obtained Medicaid. Participants included 14 409 children aged 2 to 18 years whose parents participated in the Oregon Experiment. EXPOSURES For intent-to-treat analyses, the date a parent was selected to apply for Medicaid was considered the date the child was exposed to the intervention. In per-protocol analyses, exposure was defined as whether a selected parent obtained Medicaid. MAIN OUTCOMES AND MEASURES Children’s Medicaid or CHIP coverage, assessed monthly and in 6-month intervals relative to their parent’s selection date. RESULTS In the immediate period after selection, children whose parents were selected to apply significantly increased from 3830 (61.4%) to 4152 (66.6%) compared with a nonsignificant change from 5049 (61.8%) to 5044 (61.7%) for children whose parents were not selected to apply. Children whose parents were randomly selected to apply for Medicaid had 18% higher odds of being covered in the first 6 months after parent’s selection compared with children whose parents were not selected (adjusted odds ratio [AOR] = 1.18; 95% CI, 1.10–1.27). The effect remained significant during months 7 to 12 (AOR = 1.11; 95% CI, 1.03–1.19); months 13 to 18 showed a positive but not significant effect (AOR = 1.07; 95% CI, 0.99–1.14). Children whose parents were selected and obtained coverage had more than double the odds of having coverage compared with children whose parents were not selected and did not gain coverage (AOR = 2.37; 95% CI, 2.14–2.64). CONCLUSIONS AND RELEVANCE Children’s odds of having Medicaid or CHIP coverage increased when their parents were randomly selected to apply for Medicaid. Children whose parents were selected and subsequently obtained coverage benefited most. This study demonstrates a causal link between parents’ access to Medicaid coverage and their children’s coverage. PMID:25561041

Hebbian Learning in a Random Network Captures Selectivity Properties of the Prefrontal Cortex.

PubMed

Lindsay, Grace W; Rigotti, Mattia; Warden, Melissa R; Miller, Earl K; Fusi, Stefano

2017-11-08

Complex cognitive behaviors, such as context-switching and rule-following, are thought to be supported by the prefrontal cortex (PFC). Neural activity in the PFC must thus be specialized to specific tasks while retaining flexibility. Nonlinear "mixed" selectivity is an important neurophysiological trait for enabling complex and context-dependent behaviors. Here we investigate (1) the extent to which the PFC exhibits computationally relevant properties, such as mixed selectivity, and (2) how such properties could arise via circuit mechanisms. We show that PFC cells recorded from male and female rhesus macaques during a complex task show a moderate level of specialization and structure that is not replicated by a model wherein cells receive random feedforward inputs. While random connectivity can be effective at generating mixed selectivity, the data show significantly more mixed selectivity than predicted by a model with otherwise matched parameters. A simple Hebbian learning rule applied to the random connectivity, however, increases mixed selectivity and enables the model to match the data more accurately. To explain how learning achieves this, we provide analysis along with a clear geometric interpretation of the impact of learning on selectivity. After learning, the model also matches the data on measures of noise, response density, clustering, and the distribution of selectivities. Of two styles of Hebbian learning tested, the simpler and more biologically plausible option better matches the data. These modeling results provide clues about how neural properties important for cognition can arise in a circuit and make clear experimental predictions regarding how various measures of selectivity would evolve during animal training. SIGNIFICANCE STATEMENT The prefrontal cortex is a brain region believed to support the ability of animals to engage in complex behavior. How neurons in this area respond to stimuli-and in particular, to combinations of stimuli ("mixed selectivity")-is a topic of interest. Even though models with random feedforward connectivity are capable of creating computationally relevant mixed selectivity, such a model does not match the levels of mixed selectivity seen in the data analyzed in this study. Adding simple Hebbian learning to the model increases mixed selectivity to the correct level and makes the model match the data on several other relevant measures. This study thus offers predictions on how mixed selectivity and other properties evolve with training. Copyright © 2017 the authors 0270-6474/17/3711021-16$15.00/0.

Limited Effects of a 2-Year School-Based Physical Activity Intervention on Body Composition and Cardiorespiratory Fitness in 7-Year-Old Children

ERIC Educational Resources Information Center

Magnusson, Kristjan Thor; Hrafnkelsson, Hannes; Sigurgeirsson, Ingvar; Johannsson, Erlingur; Sveinsson, Thorarinn

2012-01-01

The aim of this study was to assess the effects of a 2-year cluster-randomized physical activity and dietary intervention program among 7-year-old (at baseline) elementary school participants on body composition and objectively measured cardiorespiratory fitness. Three pairs of schools were selected and matched, then randomly selected as either an…

The Long-Term Effectiveness of a Selective, Personality-Targeted Prevention Program in Reducing Alcohol Use and Related Harms: A Cluster Randomized Controlled Trial

ERIC Educational Resources Information Center

Newton, Nicola C.; Conrod, Patricia J.; Slade, Tim; Carragher, Natacha; Champion, Katrina E.; Barrett, Emma L.; Kelly, Erin V.; Nair, Natasha K.; Stapinski, Lexine; Teesson, Maree

2016-01-01

Background: This study investigated the long-term effectiveness of Preventure, a selective personality-targeted prevention program, in reducing the uptake of alcohol, harmful use of alcohol, and alcohol-related harms over a 3-year period. Methods: A cluster randomized controlled trial was conducted to assess the effectiveness of Preventure.…

US EPA Base Study Standard Operating Procedure for Building Recruiting

EPA Pesticide Factsheets

Building recruiting for the BASE study is defined by a random selection of buildings within cities of population exceeding 100,000 inhabitants and located in selected climatic regions of the United States.

Balancing Participation across Students in Large College Classes via Randomized Participation Credit

ERIC Educational Resources Information Center

McCleary, Daniel F.; Aspiranti, Kathleen B.; Foster, Lisa N.; Blondin, Carolyn A.; Gaylon, Charles E.; Yaw, Jared S.; Forbes, Bethany N.; Williams, Robert L.

2011-01-01

The study examines the effects of randomized credit on the percentage of students participating at four predefined levels. Students recorded their comments on specially designed record cards, and days were randomly selected for participation credit. This arrangement balanced participation across students while cutting instructor time for recording…

Hebbian Learning in a Random Network Captures Selectivity Properties of the Prefrontal Cortex

PubMed Central

Lindsay, Grace W.

2017-01-01

Complex cognitive behaviors, such as context-switching and rule-following, are thought to be supported by the prefrontal cortex (PFC). Neural activity in the PFC must thus be specialized to specific tasks while retaining flexibility. Nonlinear “mixed” selectivity is an important neurophysiological trait for enabling complex and context-dependent behaviors. Here we investigate (1) the extent to which the PFC exhibits computationally relevant properties, such as mixed selectivity, and (2) how such properties could arise via circuit mechanisms. We show that PFC cells recorded from male and female rhesus macaques during a complex task show a moderate level of specialization and structure that is not replicated by a model wherein cells receive random feedforward inputs. While random connectivity can be effective at generating mixed selectivity, the data show significantly more mixed selectivity than predicted by a model with otherwise matched parameters. A simple Hebbian learning rule applied to the random connectivity, however, increases mixed selectivity and enables the model to match the data more accurately. To explain how learning achieves this, we provide analysis along with a clear geometric interpretation of the impact of learning on selectivity. After learning, the model also matches the data on measures of noise, response density, clustering, and the distribution of selectivities. Of two styles of Hebbian learning tested, the simpler and more biologically plausible option better matches the data. These modeling results provide clues about how neural properties important for cognition can arise in a circuit and make clear experimental predictions regarding how various measures of selectivity would evolve during animal training. SIGNIFICANCE STATEMENT The prefrontal cortex is a brain region believed to support the ability of animals to engage in complex behavior. How neurons in this area respond to stimuli—and in particular, to combinations of stimuli (“mixed selectivity”)—is a topic of interest. Even though models with random feedforward connectivity are capable of creating computationally relevant mixed selectivity, such a model does not match the levels of mixed selectivity seen in the data analyzed in this study. Adding simple Hebbian learning to the model increases mixed selectivity to the correct level and makes the model match the data on several other relevant measures. This study thus offers predictions on how mixed selectivity and other properties evolve with training. PMID:28986463

Perceived Indices of Truancy among Selected Adolescents in Oyo Town: Implications for Behavioural Change

ERIC Educational Resources Information Center

Adika, Lawrence Olagoke

2016-01-01

The study investigated perceived indices of truancy behaviour among selected adolescents in Oyo town. The descriptive survey study had 200 randomly selected adolescents from five secondary schools in Oyo town. A self-designed instrument tagged Adolescent Truancy Scale (ATS) was employed in collecting data for the study and the data was subjected…

Selective Attentional Effects of Adjunct Study Questions on Achievement in Nigerian Secondary School Science

ERIC Educational Resources Information Center

Okoye, Nnamdi S.

2008-01-01

The study investigated the selective attentional effects of adjunct study questions inserted before or after the presentation of science flow diagrams. The basic design for the study was a post-test only control group design involving a total of 252 students randomly selected from six secondary schools in Ile-Ife, Oshun State Nigeria. These were…

Estimating causal contrasts involving intermediate variables in the presence of selection bias.

PubMed

Valeri, Linda; Coull, Brent A

2016-11-20

An important goal across the biomedical and social sciences is the quantification of the role of intermediate factors in explaining how an exposure exerts an effect on an outcome. Selection bias has the potential to severely undermine the validity of inferences on direct and indirect causal effects in observational as well as in randomized studies. The phenomenon of selection may arise through several mechanisms, and we here focus on instances of missing data. We study the sign and magnitude of selection bias in the estimates of direct and indirect effects when data on any of the factors involved in the analysis is either missing at random or not missing at random. Under some simplifying assumptions, the bias formulae can lead to nonparametric sensitivity analyses. These sensitivity analyses can be applied to causal effects on the risk difference and risk-ratio scales irrespectively of the estimation approach employed. To incorporate parametric assumptions, we also develop a sensitivity analysis for selection bias in mediation analysis in the spirit of the expectation-maximization algorithm. The approaches are applied to data from a health disparities study investigating the role of stage at diagnosis on racial disparities in colorectal cancer survival. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Tehran Air Pollutants Prediction Based on Random Forest Feature Selection Method

NASA Astrophysics Data System (ADS)

Shamsoddini, A.; Aboodi, M. R.; Karami, J.

2017-09-01

Air pollution as one of the most serious forms of environmental pollutions poses huge threat to human life. Air pollution leads to environmental instability, and has harmful and undesirable effects on the environment. Modern prediction methods of the pollutant concentration are able to improve decision making and provide appropriate solutions. This study examines the performance of the Random Forest feature selection in combination with multiple-linear regression and Multilayer Perceptron Artificial Neural Networks methods, in order to achieve an efficient model to estimate carbon monoxide and nitrogen dioxide, sulfur dioxide and PM2.5 contents in the air. The results indicated that Artificial Neural Networks fed by the attributes selected by Random Forest feature selection method performed more accurate than other models for the modeling of all pollutants. The estimation accuracy of sulfur dioxide emissions was lower than the other air contaminants whereas the nitrogen dioxide was predicted more accurate than the other pollutants.

COMPARISON OF RANDOM AND SYSTEMATIC SITE SELECTION FOR ASSESSING ATTAINMENT OF AQUATIC LIFE USES IN SEGMENTS OF THE OHIO RIVER

EPA Science Inventory

This report is a description of field work and data analysis results comparing a design comparable to systematic site selection with one based on random selection of sites. The report is expected to validate the use of random site selection in the bioassessment program for the O...

Effects of zinc supplementation on subscales of anorexia in children: A randomized controlled trial

PubMed Central

Khademian, Majid; Farhangpajouh, Neda; Shahsanaee, Armindokht; Bahreynian, Maryam; Mirshamsi, Mehran; Kelishadi, Roya

2014-01-01

Objectives: This study aims to assess the effects of zinc supplementation on improving the appetite and its subscales in children. Methods: This study was conducted in 2013 in Isfahan, Iran. It had two phases. At the first step, after validation of the Child Eating Behaviour Questionaire (CEBQ), it was completed for 300 preschool children, who were randomly selected. The second phase was conducted as a randomized controlled trial. Eighty of these children were randomly selected, and were randomly assigned to two groups of equal number receiving zinc (10 mg/day) or placebo for 12 weeks. Results: Overall 77 children completed the trial (39 in the case and 3 in the control group).The results showed that zinc supplement can improve calorie intake in children by affecting some CEBQ subscales like Emotional over Eating and Food Responsible. Conclusion: Zinc supplementation had positive impact in promoting the calorie intake and some subscales of anorexia. PMID:25674110

Extensively Parameterized Mutation-Selection Models Reliably Capture Site-Specific Selective Constraint.

PubMed

Spielman, Stephanie J; Wilke, Claus O

2016-11-01

The mutation-selection model of coding sequence evolution has received renewed attention for its use in estimating site-specific amino acid propensities and selection coefficient distributions. Two computationally tractable mutation-selection inference frameworks have been introduced: One framework employs a fixed-effects, highly parameterized maximum likelihood approach, whereas the other employs a random-effects Bayesian Dirichlet Process approach. While both implementations follow the same model, they appear to make distinct predictions about the distribution of selection coefficients. The fixed-effects framework estimates a large proportion of highly deleterious substitutions, whereas the random-effects framework estimates that all substitutions are either nearly neutral or weakly deleterious. It remains unknown, however, how accurately each method infers evolutionary constraints at individual sites. Indeed, selection coefficient distributions pool all site-specific inferences, thereby obscuring a precise assessment of site-specific estimates. Therefore, in this study, we use a simulation-based strategy to determine how accurately each approach recapitulates the selective constraint at individual sites. We find that the fixed-effects approach, despite its extensive parameterization, consistently and accurately estimates site-specific evolutionary constraint. By contrast, the random-effects Bayesian approach systematically underestimates the strength of natural selection, particularly for slowly evolving sites. We also find that, despite the strong differences between their inferred selection coefficient distributions, the fixed- and random-effects approaches yield surprisingly similar inferences of site-specific selective constraint. We conclude that the fixed-effects mutation-selection framework provides the more reliable software platform for model application and future development. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Randomness and diversity matter in the maintenance of the public resources

NASA Astrophysics Data System (ADS)

Liu, Aizhi; Zhang, Yanling; Chen, Xiaojie; Sun, Changyin

2017-03-01

Most previous models about the public goods game usually assume two possible strategies, i.e., investing all or nothing. The real-life situation is rarely all or nothing. In this paper, we consider that multiple strategies are adopted in a well-mixed population, and each strategy represents an investment to produce the public goods. Past efforts have found that randomness matters in the evolution of fairness in the ultimatum game. In the framework involving no other mechanisms, we study how diversity and randomness influence the average investment of the population defined by the mean value of all individuals' strategies. The level of diversity is increased by increasing the strategy number, and the level of randomness is increased by increasing the mutation probability, or decreasing the population size or the selection intensity. We find that a higher level of diversity and a higher level of randomness lead to larger average investment and favor more the evolution of cooperation. Under weak selection, the average investment changes very little with the strategy number, the population size, and the mutation probability. Under strong selection, the average investment changes very little with the strategy number and the population size, but changes a lot with the mutation probability. Under intermediate selection, the average investment increases significantly with the strategy number and the mutation probability, and decreases significantly with the population size. These findings are meaningful to study how to maintain the public resource.

The Effects of a Computerized Study Program on the Acquisition of Science Vocabulary

ERIC Educational Resources Information Center

Rollins, Karen F.

2012-01-01

The following study examined the difference in science vocabulary acquisition comparing computer-assisted learning and a traditional study review sheet. Fourth and fifth grade students from a suburban school in central Texas were randomly selected and randomly assigned to either experimental group or control group. Both groups were given a…

Free variable selection QSPR study to predict 19F chemical shifts of some fluorinated organic compounds using Random Forest and RBF-PLS methods

NASA Astrophysics Data System (ADS)

Goudarzi, Nasser

2016-04-01

In this work, two new and powerful chemometrics methods are applied for the modeling and prediction of the 19F chemical shift values of some fluorinated organic compounds. The radial basis function-partial least square (RBF-PLS) and random forest (RF) are employed to construct the models to predict the 19F chemical shifts. In this study, we didn't used from any variable selection method and RF method can be used as variable selection and modeling technique. Effects of the important parameters affecting the ability of the RF prediction power such as the number of trees (nt) and the number of randomly selected variables to split each node (m) were investigated. The root-mean-square errors of prediction (RMSEP) for the training set and the prediction set for the RBF-PLS and RF models were 44.70, 23.86, 29.77, and 23.69, respectively. Also, the correlation coefficients of the prediction set for the RBF-PLS and RF models were 0.8684 and 0.9313, respectively. The results obtained reveal that the RF model can be used as a powerful chemometrics tool for the quantitative structure-property relationship (QSPR) studies.

Roosting habitat use and selection by northern spotted owls during natal dispersal

USGS Publications Warehouse

Sovern, Stan G.; Forsman, Eric D.; Dugger, Catherine M.; Taylor, Margaret

2015-01-01

We studied habitat selection by northern spotted owls (Strix occidentalis caurina) during natal dispersal in Washington State, USA, at both the roost site and landscape scales. We used logistic regression to obtain parameters for an exponential resource selection function based on vegetation attributes in roost and random plots in 76 forest stands that were used for roosting. We used a similar analysis to evaluate selection of landscape habitat attributes based on 301 radio-telemetry relocations and random points within our study area. We found no evidence of within-stand selection for any of the variables examined, but 78% of roosts were in stands with at least some large (>50 cm dbh) trees. At the landscape scale, owls selected for stands with high canopy cover (>70%). Dispersing owls selected vegetation types that were more similar to habitat selected by adult owls than habitat that would result from following guidelines previously proposed to maintain dispersal habitat. Our analysis indicates that juvenile owls select stands for roosting that have greater canopy cover than is recommended in current agency guidelines.

Randomizing Roaches: Exploring the "Bugs" of Randomization in Experimental Design

ERIC Educational Resources Information Center

Wagler, Amy; Wagler, Ron

2014-01-01

Understanding the roles of random selection and random assignment in experimental design is a central learning objective in most introductory statistics courses. This article describes an activity, appropriate for a high school or introductory statistics course, designed to teach the concepts, values and pitfalls of random selection and assignment…

Random drift versus selection in academic vocabulary: an evolutionary analysis of published keywords.

PubMed

Bentley, R Alexander

2008-08-27

The evolution of vocabulary in academic publishing is characterized via keyword frequencies recorded in the ISI Web of Science citations database. In four distinct case-studies, evolutionary analysis of keyword frequency change through time is compared to a model of random copying used as the null hypothesis, such that selection may be identified against it. The case studies from the physical sciences indicate greater selection in keyword choice than in the social sciences. Similar evolutionary analyses can be applied to a wide range of phenomena; wherever the popularity of multiple items through time has been recorded, as with web searches, or sales of popular music and books, for example.

Random Drift versus Selection in Academic Vocabulary: An Evolutionary Analysis of Published Keywords

PubMed Central

Bentley, R. Alexander

2008-01-01

The evolution of vocabulary in academic publishing is characterized via keyword frequencies recorded in the ISI Web of Science citations database. In four distinct case-studies, evolutionary analysis of keyword frequency change through time is compared to a model of random copying used as the null hypothesis, such that selection may be identified against it. The case studies from the physical sciences indicate greater selection in keyword choice than in the social sciences. Similar evolutionary analyses can be applied to a wide range of phenomena; wherever the popularity of multiple items through time has been recorded, as with web searches, or sales of popular music and books, for example. PMID:18728786

Environmental Exposures, Genetic Polymorphisms and p53 Mutational Spectra in a Case-Control Study of Breast Cancer.

DTIC Science & Technology

1998-01-01

Further, preliminary clinical data suggest that serotonin reuptake inhibitors , such as fluoxetinc hydrochloride, may promote smoking cessation (15,16...benefits of serotonin reuptake inhibitors in smoking cessation (16) suggested that this gene may be a plausible candidate for predisposition to... used for random selection of women under age 65; women age 65 and over were randomly selected from the listing of the Health Care Finance

Use of Matrix Sampling Procedures to Assess Achievement in Solving Open Addition and Subtraction Sentences.

ERIC Educational Resources Information Center

Montague, Margariete A.

This study investigated the feasibility of concurrently and randomly sampling examinees and items in order to estimate group achievement. Seven 32-item tests reflecting a 640-item universe of simple open sentences were used such that item selection (random, systematic) and assignment (random, systematic) of items (four, eight, sixteen) to forms…

Day-roost tree selection by northern long-eared bats—What do non-roost tree comparisons and one year of data really tell us?

USGS Publications Warehouse

Silvis, Alexander; Ford, W. Mark; Britzke, Eric R.

2015-01-01

Bat day-roost selection often is described through comparisons of day-roosts with randomly selected, and assumed unused, trees. Relatively few studies, however, look at patterns of multi-year selection or compare day-roosts used across years. We explored day-roost selection using 2 years of roost selection data for female northern long-eared bats (Myotis septentrionalis) on the Fort Knox Military Reservation, Kentucky, USA. We compared characteristics of randomly selected non-roost trees and day-roosts using a multinomial logistic model and day-roost species selection using chi-squared tests. We found that factors differentiating day-roosts from non-roosts and day-roosts between years varied. Day-roosts differed from non-roosts in the first year of data in all measured factors, but only in size and decay stage in the second year. Between years, day-roosts differed in size and canopy position, but not decay stage. Day-roost species selection was non-random and did not differ between years. Although bats used multiple trees, our results suggest that there were additional unused trees that were suitable as roosts at any time. Day-roost selection pattern descriptions will be inadequate if based only on a single year of data, and inferences of roost selection based only on comparisons of roost to non-roosts should be limited.

Day-roost tree selection by northern long-eared bats - What do non-roost tree comparisons and one year of data really tell us?

USGS Publications Warehouse

Silvis, Alexander; Ford, W. Mark; Britzke, Eric R.

2015-01-01

Bat day-roost selection often is described through comparisons of day-roosts with randomly selected, and assumed unused, trees. Relatively few studies, however, look at patterns of multi-year selection or compare day-roosts used across years. We explored day-roost selection using 2 years of roost selection data for female northern long-eared bats (Myotis septentrionalis) on the Fort Knox Military Reservation, Kentucky, USA. We compared characteristics of randomly selected non-roost trees and day-roosts using a multinomial logistic model and day-roost species selection using chi-squared tests. We found that factors differentiating day-roosts from non-roosts and day-roosts between years varied. Day-roosts differed from non-roosts in the first year of data in all measured factors, but only in size and decay stage in the second year. Between years, day-roosts differed in size and canopy position, but not decay stage. Day-roost species selection was non-random and did not differ between years. Although bats used multiple trees, our results suggest that there were additional unused trees that were suitable as roosts at any time. Day-roost selection pattern descriptions will be inadequate if based only on a single year of data, and inferences of roost selection based only on comparisons of roost to non-roosts should be limited.

[Study on correction of data bias caused by different missing mechanisms in survey of medical expenditure among students enrolling in Urban Resident Basic Medical Insurance].

PubMed

Zhang, Haixia; Zhao, Junkang; Gu, Caijiao; Cui, Yan; Rong, Huiying; Meng, Fanlong; Wang, Tong

2015-05-01

The study of the medical expenditure and its influencing factors among the students enrolling in Urban Resident Basic Medical Insurance (URBMI) in Taiyuan indicated that non response bias and selection bias coexist in dependent variable of the survey data. Unlike previous studies only focused on one missing mechanism, a two-stage method to deal with two missing mechanisms simultaneously was suggested in this study, combining multiple imputation with sample selection model. A total of 1 190 questionnaires were returned by the students (or their parents) selected in child care settings, schools and universities in Taiyuan by stratified cluster random sampling in 2012. In the returned questionnaires, 2.52% existed not missing at random (NMAR) of dependent variable and 7.14% existed missing at random (MAR) of dependent variable. First, multiple imputation was conducted for MAR by using completed data, then sample selection model was used to correct NMAR in multiple imputation, and a multi influencing factor analysis model was established. Based on 1 000 times resampling, the best scheme of filling the random missing values is the predictive mean matching (PMM) method under the missing proportion. With this optimal scheme, a two stage survey was conducted. Finally, it was found that the influencing factors on annual medical expenditure among the students enrolling in URBMI in Taiyuan included population group, annual household gross income, affordability of medical insurance expenditure, chronic disease, seeking medical care in hospital, seeking medical care in community health center or private clinic, hospitalization, hospitalization canceled due to certain reason, self medication and acceptable proportion of self-paid medical expenditure. The two-stage method combining multiple imputation with sample selection model can deal with non response bias and selection bias effectively in dependent variable of the survey data.

Goal selection versus process control while learning to use a brain-computer interface

NASA Astrophysics Data System (ADS)

Royer, Audrey S.; Rose, Minn L.; He, Bin

2011-06-01

A brain-computer interface (BCI) can be used to accomplish a task without requiring motor output. Two major control strategies used by BCIs during task completion are process control and goal selection. In process control, the user exerts continuous control and independently executes the given task. In goal selection, the user communicates their goal to the BCI and then receives assistance executing the task. A previous study has shown that goal selection is more accurate and faster in use. An unanswered question is, which control strategy is easier to learn? This study directly compares goal selection and process control while learning to use a sensorimotor rhythm-based BCI. Twenty young healthy human subjects were randomly assigned either to a goal selection or a process control-based paradigm for eight sessions. At the end of the study, the best user from each paradigm completed two additional sessions using all paradigms randomly mixed. The results of this study were that goal selection required a shorter training period for increased speed, accuracy, and information transfer over process control. These results held for the best subjects as well as in the general subject population. The demonstrated characteristics of goal selection make it a promising option to increase the utility of BCIs intended for both disabled and able-bodied users.

Does self-selection affect samples' representativeness in online surveys? An investigation in online video game research.

PubMed

Khazaal, Yasser; van Singer, Mathias; Chatton, Anne; Achab, Sophia; Zullino, Daniele; Rothen, Stephane; Khan, Riaz; Billieux, Joel; Thorens, Gabriel

2014-07-07

The number of medical studies performed through online surveys has increased dramatically in recent years. Despite their numerous advantages (eg, sample size, facilitated access to individuals presenting stigmatizing issues), selection bias may exist in online surveys. However, evidence on the representativeness of self-selected samples in online studies is patchy. Our objective was to explore the representativeness of a self-selected sample of online gamers using online players' virtual characters (avatars). All avatars belonged to individuals playing World of Warcraft (WoW), currently the most widely used online game. Avatars' characteristics were defined using various games' scores, reported on the WoW's official website, and two self-selected samples from previous studies were compared with a randomly selected sample of avatars. We used scores linked to 1240 avatars (762 from the self-selected samples and 478 from the random sample). The two self-selected samples of avatars had higher scores on most of the assessed variables (except for guild membership and exploration). Furthermore, some guilds were overrepresented in the self-selected samples. Our results suggest that more proficient players or players more involved in the game may be more likely to participate in online surveys. Caution is needed in the interpretation of studies based on online surveys that used a self-selection recruitment procedure. Epidemiological evidence on the reduced representativeness of sample of online surveys is warranted.

76 FR 74076 - Notice of Random Assignment Study To Evaluate the YouthBuild Program; Final Notice

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-30

... Evaluate the YouthBuild Program; Final Notice AGENCY: Employment and Training Administration (ETA), Labor... rigorous, nationally-representative estimates of the net impacts of the YouthBuild program. The Department... study. In the sites randomly selected to participate in this evaluation, all applicants for YouthBuild...

Adiposity and Quality of Life: A Case Study from an Urban Center in Nigeria

ERIC Educational Resources Information Center

Akinpelu, Aderonke O.; Akinola, Odunayo T.; Gbiri, Caleb A.

2009-01-01

Objective: To determine relationship between adiposity indices and quality of life (QOL) of residents of a housing estate in Lagos, Nigeria. Design: Cross-sectional survey employing multistep random sampling method. Setting: Urban residential estate. Participants: This study involved 900 randomly selected residents of Abesan Housing Estate, Lagos,…

CTEPP STANDARD OPERATING PROCEDURE FOR SAMPLE SELECTION (SOP-1.10)

EPA Science Inventory

The procedures for selecting CTEPP study subjects are described in the SOP. The primary, county-level stratification is by region and urbanicity. Six sample counties in each of the two states (North Carolina and Ohio) are selected using stratified random sampling and reflect ...

Ray tracing method for simulation of laser beam interaction with random packings of powders

NASA Astrophysics Data System (ADS)

Kovalev, O. B.; Kovaleva, I. O.; Belyaev, V. V.

2018-03-01

Selective laser sintering is a technology of rapid manufacturing of a free form that is created as a solid object by selectively fusing successive layers of powder using a laser. The motivation of this study is due to the currently insufficient understanding of the processes and phenomena of selective laser melting of powders whose time scales differ by orders of magnitude. To construct random packings from mono- and polydispersed solid spheres, the algorithm of their generation based on the discrete element method is used. A numerical method of ray tracing is proposed that is used to simulate the interaction of laser radiation with a random bulk packing of spherical particles and to predict the optical properties of the granular layer, the extinction and absorption coefficients, depending on the optical properties of a powder material.

A morphologic analysis of 'naked' islets of Langerhans in lobular atrophy of the pancreas.

PubMed

Suda, K; Tsukahara, M; Miyake, T; Hirai, S

1994-08-01

The 'naked' islets of Langerhans (NIL) in randomly selected autopsy cases and in cases of chronic alcoholic pancreatitis, cystic fibrosis, and pancreatic carcinoma were studied histopathologically. The NIL were found in 55 of 164 randomly selected cases, with age-related frequency, in 21 of 30 cases of chronic alcoholic pancreatitis, in 2 of 2 cases of cystic fibrosis, and in 25 of 32 cases of pancreatic carcinoma. The NIL were frequently accompanied by ductal alterations: epithelial metaplasia and hyperplasia in randomly selected cases, protein plugs in chronic alcoholic pancreatitis, mucus plugs in cystic fibrosis, and obliterated ducts in pancreatic carcinoma. The NIL in randomly selected cases may have been formed by ductal alterations that caused stenosis of the lumen, those in chronic alcoholic pancreatitis and cystic fibrosis were the result of protein or mucus plugging, and those in pancreatic carcinoma were a result of neoplastic involvement of the distal pancreatic duct. Therefore, the common factor in the development of NIL is thought to be obstruction of the pancreatic duct system, and in cases of NIL that have a multilobular distribution and interinsular fibrosis, a diagnosis of chronic pancreatitis can usually be made.

Using ArcMap, Google Earth, and Global Positioning Systems to select and locate random households in rural Haiti.

PubMed

Wampler, Peter J; Rediske, Richard R; Molla, Azizur R

2013-01-18

A remote sensing technique was developed which combines a Geographic Information System (GIS); Google Earth, and Microsoft Excel to identify home locations for a random sample of households in rural Haiti. The method was used to select homes for ethnographic and water quality research in a region of rural Haiti located within 9 km of a local hospital and source of health education in Deschapelles, Haiti. The technique does not require access to governmental records or ground based surveys to collect household location data and can be performed in a rapid, cost-effective manner. The random selection of households and the location of these households during field surveys were accomplished using GIS, Google Earth, Microsoft Excel, and handheld Garmin GPSmap 76CSx GPS units. Homes were identified and mapped in Google Earth, exported to ArcMap 10.0, and a random list of homes was generated using Microsoft Excel which was then loaded onto handheld GPS units for field location. The development and use of a remote sensing method was essential to the selection and location of random households. A total of 537 homes initially were mapped and a randomized subset of 96 was identified as potential survey locations. Over 96% of the homes mapped using Google Earth imagery were correctly identified as occupied dwellings. Only 3.6% of the occupants of mapped homes visited declined to be interviewed. 16.4% of the homes visited were not occupied at the time of the visit due to work away from the home or market days. A total of 55 households were located using this method during the 10 days of fieldwork in May and June of 2012. The method used to generate and field locate random homes for surveys and water sampling was an effective means of selecting random households in a rural environment lacking geolocation infrastructure. The success rate for locating households using a handheld GPS was excellent and only rarely was local knowledge required to identify and locate households. This method provides an important technique that can be applied to other developing countries where a randomized study design is needed but infrastructure is lacking to implement more traditional participant selection methods.

Utility and Cost-Effectiveness of Motivational Messaging to Increase Survey Response in Physicians: A Randomized Controlled Trial

ERIC Educational Resources Information Center

Chan, Randolph C. H.; Mak, Winnie W. S.; Pang, Ingrid H. Y.; Wong, Samuel Y. S.; Tang, Wai Kwong; Lau, Joseph T. F.; Woo, Jean; Lee, Diana T. F.; Cheung, Fanny M.

2018-01-01

The present study examined whether, when, and how motivational messaging can boost the response rate of postal surveys for physicians based on Higgin's regulatory focus theory, accounting for its cost-effectiveness. A three-arm, blinded, randomized controlled design was used. A total of 3,270 doctors were randomly selected from the registration…

The Ecological Effects of Universal and Selective Violence Prevention Programs for Middle School Students: A Randomized Trial

ERIC Educational Resources Information Center

Simon, Thomas R.; Ikeda, Robin M.; Smith, Emilie Phillips; Reese, Le'Roy E.; Rabiner, David L.; Miller, Shari; Winn, Donna-Marie; Dodge, Kenneth A.; Asher, Steven R.; Horne, Arthur M.; Orpinas, Pamela; Martin, Roy; Quinn, William H.; Tolan, Patrick H.; Gorman-Smith, Deborah; Henry, David B.; Gay, Franklin N.; Schoeny, Michael; Farrell, Albert D.; Meyer, Aleta L.; Sullivan, Terri N.; Allison, Kevin W.

2009-01-01

This study reports the findings of a multisite randomized trial evaluating the separate and combined effects of 2 school-based approaches to reduce violence among early adolescents. A total of 37 schools at 4 sites were randomized to 4 conditions: (1) a universal intervention that involved implementing a student curriculum and teacher training…

Generation of Aptamers from A Primer-Free Randomized ssDNA Library Using Magnetic-Assisted Rapid Aptamer Selection

NASA Astrophysics Data System (ADS)

Tsao, Shih-Ming; Lai, Ji-Ching; Horng, Horng-Er; Liu, Tu-Chen; Hong, Chin-Yih

2017-04-01

Aptamers are oligonucleotides that can bind to specific target molecules. Most aptamers are generated using random libraries in the standard systematic evolution of ligands by exponential enrichment (SELEX). Each random library contains oligonucleotides with a randomized central region and two fixed primer regions at both ends. The fixed primer regions are necessary for amplifying target-bound sequences by PCR. However, these extra-sequences may cause non-specific bindings, which potentially interfere with good binding for random sequences. The Magnetic-Assisted Rapid Aptamer Selection (MARAS) is a newly developed protocol for generating single-strand DNA aptamers. No repeat selection cycle is required in the protocol. This study proposes and demonstrates a method to isolate aptamers for C-reactive proteins (CRP) from a randomized ssDNA library containing no fixed sequences at 5‧ and 3‧ termini using the MARAS platform. Furthermore, the isolated primer-free aptamer was sequenced and binding affinity for CRP was analyzed. The specificity of the obtained aptamer was validated using blind serum samples. The result was consistent with monoclonal antibody-based nephelometry analysis, which indicated that a primer-free aptamer has high specificity toward targets. MARAS is a feasible platform for efficiently generating primer-free aptamers for clinical diagnoses.

Correlates of Attitudes toward Academic and Physical Inclusive Practices for Students with Disabilities and Selected Leadership Behaviors among Middle School Principals in North Carolina

ERIC Educational Resources Information Center

Houser, Mary A.; Dickens, Virginia; Hicks, Terence

2011-01-01

The purpose of the study was to examine the relationship between attitudes toward academic and inclusive practices for students with disabilities and selected leadership behaviors (transformational and transactional) among principals in North Carolina. Participants for this study were randomly selected middle school principals from public schools…

Methodology Series Module 5: Sampling Strategies.

PubMed

Setia, Maninder Singh

2016-01-01

Once the research question and the research design have been finalised, it is important to select the appropriate sample for the study. The method by which the researcher selects the sample is the ' Sampling Method'. There are essentially two types of sampling methods: 1) probability sampling - based on chance events (such as random numbers, flipping a coin etc.); and 2) non-probability sampling - based on researcher's choice, population that accessible & available. Some of the non-probability sampling methods are: purposive sampling, convenience sampling, or quota sampling. Random sampling method (such as simple random sample or stratified random sample) is a form of probability sampling. It is important to understand the different sampling methods used in clinical studies and mention this method clearly in the manuscript. The researcher should not misrepresent the sampling method in the manuscript (such as using the term ' random sample' when the researcher has used convenience sample). The sampling method will depend on the research question. For instance, the researcher may want to understand an issue in greater detail for one particular population rather than worry about the ' generalizability' of these results. In such a scenario, the researcher may want to use ' purposive sampling' for the study.

Methodology Series Module 5: Sampling Strategies

PubMed Central

Setia, Maninder Singh

2016-01-01

Once the research question and the research design have been finalised, it is important to select the appropriate sample for the study. The method by which the researcher selects the sample is the ‘ Sampling Method’. There are essentially two types of sampling methods: 1) probability sampling – based on chance events (such as random numbers, flipping a coin etc.); and 2) non-probability sampling – based on researcher's choice, population that accessible & available. Some of the non-probability sampling methods are: purposive sampling, convenience sampling, or quota sampling. Random sampling method (such as simple random sample or stratified random sample) is a form of probability sampling. It is important to understand the different sampling methods used in clinical studies and mention this method clearly in the manuscript. The researcher should not misrepresent the sampling method in the manuscript (such as using the term ‘ random sample’ when the researcher has used convenience sample). The sampling method will depend on the research question. For instance, the researcher may want to understand an issue in greater detail for one particular population rather than worry about the ‘ generalizability’ of these results. In such a scenario, the researcher may want to use ‘ purposive sampling’ for the study. PMID:27688438

An Assessment on Awareness and Acceptability of Child Adoption in Edo State

ERIC Educational Resources Information Center

Aluyor, P.; Salami, L. I.

2017-01-01

The study examines the awareness and acceptability of child adoption in Edo State. The design used for the study was survey design. The population for the study is made up of adults male and female in Esan West Local Government Area. One hundred respondents were randomly selected using random sampling techniques. The validity was ascertained by…

Intrathecal Baclofen in Children with Spastic Cerebral Palsy: A Double-Blind, Randomized, Placebo-Controlled, Dose-Finding Study

ERIC Educational Resources Information Center

Hoving, Marjanke A.; van Raak, Elisabeth P. M.; Spincemaille, Geert H. J. J.; Palmans, Liesbeth J.; Sleypen, Frans A. M.; Vles, Johan S. H.

2007-01-01

Intrathecal baclofen (ITB) therapy can be very effective in the treatment of intractable spasticity, but its effectiveness and safety have not yet been thoroughly studied in children with cerebral palsy (CP). The aims of this double-blind, randomized, placebo-controlled, dose-finding study were to select children eligible for continuous ITB…

Optimized probability sampling of study sites to improve generalizability in a multisite intervention trial.

PubMed

Kraschnewski, Jennifer L; Keyserling, Thomas C; Bangdiwala, Shrikant I; Gizlice, Ziya; Garcia, Beverly A; Johnston, Larry F; Gustafson, Alison; Petrovic, Lindsay; Glasgow, Russell E; Samuel-Hodge, Carmen D

2010-01-01

Studies of type 2 translation, the adaption of evidence-based interventions to real-world settings, should include representative study sites and staff to improve external validity. Sites for such studies are, however, often selected by convenience sampling, which limits generalizability. We used an optimized probability sampling protocol to select an unbiased, representative sample of study sites to prepare for a randomized trial of a weight loss intervention. We invited North Carolina health departments within 200 miles of the research center to participate (N = 81). Of the 43 health departments that were eligible, 30 were interested in participating. To select a representative and feasible sample of 6 health departments that met inclusion criteria, we generated all combinations of 6 from the 30 health departments that were eligible and interested. From the subset of combinations that met inclusion criteria, we selected 1 at random. Of 593,775 possible combinations of 6 counties, 15,177 (3%) met inclusion criteria. Sites in the selected subset were similar to all eligible sites in terms of health department characteristics and county demographics. Optimized probability sampling improved generalizability by ensuring an unbiased and representative sample of study sites.

Final Report of the Montana Public School Students' Out-of-School Time Study. Research Report.

ERIC Educational Resources Information Center

Astroth, Kirk A.; Haynes, George W.

This paper reports on a study that explored the results of a statewide survey conducted in 21 randomly selected counties in Montana during fall 2000. Within each county, no more than 2 school districts were selected for further study, and within each school district, students in the 5th, 7th, and 9th grades were selected to participate in the…

Pilot Study of Agricultural Literacy. Final Report.

ERIC Educational Resources Information Center

Birkenholz, Robert H.; And Others

A study assessed the knowledge and perceptions of U.S. citizens regarding agriculture, food, and natural resources. Data were collected from 2,005 respondents representing the following groups: purposely selected primarily white Indiana high school students and primarily black Michigan high school students, randomly selected rural Missouri adults…

The effect of morphometric atlas selection on multi-atlas-based automatic brachial plexus segmentation.

PubMed

Van de Velde, Joris; Wouters, Johan; Vercauteren, Tom; De Gersem, Werner; Achten, Eric; De Neve, Wilfried; Van Hoof, Tom

2015-12-23

The present study aimed to measure the effect of a morphometric atlas selection strategy on the accuracy of multi-atlas-based BP autosegmentation using the commercially available software package ADMIRE® and to determine the optimal number of selected atlases to use. Autosegmentation accuracy was measured by comparing all generated automatic BP segmentations with anatomically validated gold standard segmentations that were developed using cadavers. Twelve cadaver computed tomography (CT) atlases were included in the study. One atlas was selected as a patient in ADMIRE®, and multi-atlas-based BP autosegmentation was first performed with a group of morphometrically preselected atlases. In this group, the atlases were selected on the basis of similarity in the shoulder protraction position with the patient. The number of selected atlases used started at two and increased up to eight. Subsequently, a group of randomly chosen, non-selected atlases were taken. In this second group, every possible combination of 2 to 8 random atlases was used for multi-atlas-based BP autosegmentation. For both groups, the average Dice similarity coefficient (DSC), Jaccard index (JI) and Inclusion index (INI) were calculated, measuring the similarity of the generated automatic BP segmentations and the gold standard segmentation. Similarity indices of both groups were compared using an independent sample t-test, and the optimal number of selected atlases was investigated using an equivalence trial. For each number of atlases, average similarity indices of the morphometrically selected atlas group were significantly higher than the random group (p < 0,05). In this study, the highest similarity indices were achieved using multi-atlas autosegmentation with 6 selected atlases (average DSC = 0,598; average JI = 0,434; average INI = 0,733). Morphometric atlas selection on the basis of the protraction position of the patient significantly improves multi-atlas-based BP autosegmentation accuracy. In this study, the optimal number of selected atlases used was six, but for definitive conclusions about the optimal number of atlases and to improve the autosegmentation accuracy for clinical use, more atlases need to be included.

Differential privacy-based evaporative cooling feature selection and classification with relief-F and random forests.

PubMed

Le, Trang T; Simmons, W Kyle; Misaki, Masaya; Bodurka, Jerzy; White, Bill C; Savitz, Jonathan; McKinney, Brett A

2017-09-15

Classification of individuals into disease or clinical categories from high-dimensional biological data with low prediction error is an important challenge of statistical learning in bioinformatics. Feature selection can improve classification accuracy but must be incorporated carefully into cross-validation to avoid overfitting. Recently, feature selection methods based on differential privacy, such as differentially private random forests and reusable holdout sets, have been proposed. However, for domains such as bioinformatics, where the number of features is much larger than the number of observations p≫n , these differential privacy methods are susceptible to overfitting. We introduce private Evaporative Cooling, a stochastic privacy-preserving machine learning algorithm that uses Relief-F for feature selection and random forest for privacy preserving classification that also prevents overfitting. We relate the privacy-preserving threshold mechanism to a thermodynamic Maxwell-Boltzmann distribution, where the temperature represents the privacy threshold. We use the thermal statistical physics concept of Evaporative Cooling of atomic gases to perform backward stepwise privacy-preserving feature selection. On simulated data with main effects and statistical interactions, we compare accuracies on holdout and validation sets for three privacy-preserving methods: the reusable holdout, reusable holdout with random forest, and private Evaporative Cooling, which uses Relief-F feature selection and random forest classification. In simulations where interactions exist between attributes, private Evaporative Cooling provides higher classification accuracy without overfitting based on an independent validation set. In simulations without interactions, thresholdout with random forest and private Evaporative Cooling give comparable accuracies. We also apply these privacy methods to human brain resting-state fMRI data from a study of major depressive disorder. Code available at http://insilico.utulsa.edu/software/privateEC . brett-mckinney@utulsa.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Transferability of optimally-selected climate models in the quantification of climate change impacts on hydrology

NASA Astrophysics Data System (ADS)

Chen, Jie; Brissette, François P.; Lucas-Picher, Philippe

2016-11-01

Given the ever increasing number of climate change simulations being carried out, it has become impractical to use all of them to cover the uncertainty of climate change impacts. Various methods have been proposed to optimally select subsets of a large ensemble of climate simulations for impact studies. However, the behaviour of optimally-selected subsets of climate simulations for climate change impacts is unknown, since the transfer process from climate projections to the impact study world is usually highly non-linear. Consequently, this study investigates the transferability of optimally-selected subsets of climate simulations in the case of hydrological impacts. Two different methods were used for the optimal selection of subsets of climate scenarios, and both were found to be capable of adequately representing the spread of selected climate model variables contained in the original large ensemble. However, in both cases, the optimal subsets had limited transferability to hydrological impacts. To capture a similar variability in the impact model world, many more simulations have to be used than those that are needed to simply cover variability from the climate model variables' perspective. Overall, both optimal subset selection methods were better than random selection when small subsets were selected from a large ensemble for impact studies. However, as the number of selected simulations increased, random selection often performed better than the two optimal methods. To ensure adequate uncertainty coverage, the results of this study imply that selecting as many climate change simulations as possible is the best avenue. Where this was not possible, the two optimal methods were found to perform adequately.

Input variable selection and calibration data selection for storm water quality regression models.

PubMed

Sun, Siao; Bertrand-Krajewski, Jean-Luc

2013-01-01

Storm water quality models are useful tools in storm water management. Interest has been growing in analyzing existing data for developing models for urban storm water quality evaluations. It is important to select appropriate model inputs when many candidate explanatory variables are available. Model calibration and verification are essential steps in any storm water quality modeling. This study investigates input variable selection and calibration data selection in storm water quality regression models. The two selection problems are mutually interacted. A procedure is developed in order to fulfil the two selection tasks in order. The procedure firstly selects model input variables using a cross validation method. An appropriate number of variables are identified as model inputs to ensure that a model is neither overfitted nor underfitted. Based on the model input selection results, calibration data selection is studied. Uncertainty of model performances due to calibration data selection is investigated with a random selection method. An approach using the cluster method is applied in order to enhance model calibration practice based on the principle of selecting representative data for calibration. The comparison between results from the cluster selection method and random selection shows that the former can significantly improve performances of calibrated models. It is found that the information content in calibration data is important in addition to the size of calibration data.

A Randomized Controlled Trial of an Electronic Informed Consent Process

PubMed Central

Rothwell, Erin; Wong, Bob; Rose, Nancy C.; Anderson, Rebecca; Fedor, Beth; Stark, Louisa A.; Botkin, Jeffrey R.

2018-01-01

A pilot study assessed an electronic informed consent model within a randomized controlled trial (RCT). Participants who were recruited for the parent RCT project were randomly selected and randomized to either an electronic consent group (n = 32) or a simplified paper-based consent group (n = 30). Results from the electronic consent group reported significantly higher understanding of the purpose of the study, alternatives to participation, and who to contact if they had questions or concerns about the study. However, participants in the paper-based control group reported higher mean scores on some survey items. This research suggests that an electronic informed consent presentation may improve participant understanding for some aspects of a research study. PMID:25747685

Prevalence and pattern of self-medication in Karachi: A community survey

PubMed Central

Afridi, M. Iqbal; Rasool, Ghulam; Tabassum, Rabia; Shaheen, Marriam; Siddiqullah; Shujauddin, M.

2015-01-01

Objective: To study the prevalence and pattern of self-medication among adult males and females in Karachi, Pakistan. Methods: This cross-sectional community- based survey was carried out at five randomly selected towns of Karachi (Defence, Gulshan-e-Iqbal, North Nazimabad, Malir, Orangi town) over a period of 3 months (October, November & December 2012). A sample size of 500 adult cases (250 males & 250 females), with systemic random selection from different towns of Karachi were inducted in this study. The city was divided in 5 zones and one town from each zone was selected by systemic randomization. First available male and female from each randomly selected house were included in the study. After consent and confidentiality assurance they were interviewed on semi-structured Performa designed for this purpose. Results were analyzed and tabulated through SPSS v14.0. Result: The prevalence of self-medication in males and females in Karachi is found to be 84.8% (males 88.4% and females 81.2%). The most frequent symptoms for which self-medication used were headache (32.7%), fever (23.3%) and the medicines used were painkillers (28.8%), fever reducer medicines (19.8%). The most common reason 33.3% was previous experience with similar symptom. Conclusion: Self-medication is highly prevalent (84.8%) in Karachi. It was frequently used for headache followed by fever. Predominantly painkillers, fever reducer and cough syrups were used in the form of tablets and syrups. Main source of medicines for males were friends and for females were relatives. PMID:26649022

Escitalopram treatment of depression in human immunodeficiency virus/acquired immunodeficiency syndrome: a randomized, double-blind, placebo-controlled study.

PubMed

Hoare, Jacqueline; Carey, Paul; Joska, John A; Carrara, Henri; Sorsdahl, Katherine; Stein, Dan J

2014-02-01

Depression can be a chronic and impairing illness in people with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome. Large randomized studies of newer selective serotonin reuptake inhibitors such as escitalopram in the treatment of depression in HIV, examining comparative treatment efficacy and safety, have yet to be done in HIV-positive patients. This was a fixed-dose, placebo-controlled, randomized, double-blind study to investigate the efficacy of escitalopram in HIV-seropositive subjects with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, major depressive disorder. One hundred two participants were randomly assigned to either 10 mg of escitalopram or placebo for 6 weeks. An analysis of covariance of the completers found that there was no advantage for escitalopram over placebo on the Montgomery-Asberg Depression Rating Scale (p = 0.93). Sixty-two percent responded to escitalopram and 59% responded to placebo on the Clinical Global Impression Scale. Given the relatively high placebo response, future trials in this area need to be selective in participant recruitment and to be adequately powered.

A Comparative Study of Students' Access to and Utilization of Learning Resources in Selected Public and Private Universities in Southwest, Nigeria

ERIC Educational Resources Information Center

Lawal, B. O.; Viatonu, Olumuyiwa

2017-01-01

The study investigated students' access to and utilization of some learning resources in selected public and private universities in southwest Nigeria. Stratified random sampling technique was used to select 585 (295 public and 290 private) students from 12 (six public and six private) universities in southwest Nigeria. Two instruments--Cost and…

47 CFR 1.1604 - Post-selection hearings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Post-selection hearings. 1.1604 Section 1.1604 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE AND PROCEDURE Random Selection Procedures for Mass Media Services General Procedures § 1.1604 Post-selection hearings. (a) Following the random...

47 CFR 1.1604 - Post-selection hearings.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 1 2011-10-01 2011-10-01 false Post-selection hearings. 1.1604 Section 1.1604 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE AND PROCEDURE Random Selection Procedures for Mass Media Services General Procedures § 1.1604 Post-selection hearings. (a) Following the random...

Sampling in health geography: reconciling geographical objectives and probabilistic methods. An example of a health survey in Vientiane (Lao PDR)

PubMed Central

Vallée, Julie; Souris, Marc; Fournet, Florence; Bochaton, Audrey; Mobillion, Virginie; Peyronnie, Karine; Salem, Gérard

2007-01-01

Background Geographical objectives and probabilistic methods are difficult to reconcile in a unique health survey. Probabilistic methods focus on individuals to provide estimates of a variable's prevalence with a certain precision, while geographical approaches emphasise the selection of specific areas to study interactions between spatial characteristics and health outcomes. A sample selected from a small number of specific areas creates statistical challenges: the observations are not independent at the local level, and this results in poor statistical validity at the global level. Therefore, it is difficult to construct a sample that is appropriate for both geographical and probability methods. Methods We used a two-stage selection procedure with a first non-random stage of selection of clusters. Instead of randomly selecting clusters, we deliberately chose a group of clusters, which as a whole would contain all the variation in health measures in the population. As there was no health information available before the survey, we selected a priori determinants that can influence the spatial homogeneity of the health characteristics. This method yields a distribution of variables in the sample that closely resembles that in the overall population, something that cannot be guaranteed with randomly-selected clusters, especially if the number of selected clusters is small. In this way, we were able to survey specific areas while minimising design effects and maximising statistical precision. Application We applied this strategy in a health survey carried out in Vientiane, Lao People's Democratic Republic. We selected well-known health determinants with unequal spatial distribution within the city: nationality and literacy. We deliberately selected a combination of clusters whose distribution of nationality and literacy is similar to the distribution in the general population. Conclusion This paper describes the conceptual reasoning behind the construction of the survey sample and shows that it can be advantageous to choose clusters using reasoned hypotheses, based on both probability and geographical approaches, in contrast to a conventional, random cluster selection strategy. PMID:17543100

Sampling in health geography: reconciling geographical objectives and probabilistic methods. An example of a health survey in Vientiane (Lao PDR).

PubMed

Vallée, Julie; Souris, Marc; Fournet, Florence; Bochaton, Audrey; Mobillion, Virginie; Peyronnie, Karine; Salem, Gérard

2007-06-01

Geographical objectives and probabilistic methods are difficult to reconcile in a unique health survey. Probabilistic methods focus on individuals to provide estimates of a variable's prevalence with a certain precision, while geographical approaches emphasise the selection of specific areas to study interactions between spatial characteristics and health outcomes. A sample selected from a small number of specific areas creates statistical challenges: the observations are not independent at the local level, and this results in poor statistical validity at the global level. Therefore, it is difficult to construct a sample that is appropriate for both geographical and probability methods. We used a two-stage selection procedure with a first non-random stage of selection of clusters. Instead of randomly selecting clusters, we deliberately chose a group of clusters, which as a whole would contain all the variation in health measures in the population. As there was no health information available before the survey, we selected a priori determinants that can influence the spatial homogeneity of the health characteristics. This method yields a distribution of variables in the sample that closely resembles that in the overall population, something that cannot be guaranteed with randomly-selected clusters, especially if the number of selected clusters is small. In this way, we were able to survey specific areas while minimising design effects and maximising statistical precision. We applied this strategy in a health survey carried out in Vientiane, Lao People's Democratic Republic. We selected well-known health determinants with unequal spatial distribution within the city: nationality and literacy. We deliberately selected a combination of clusters whose distribution of nationality and literacy is similar to the distribution in the general population. This paper describes the conceptual reasoning behind the construction of the survey sample and shows that it can be advantageous to choose clusters using reasoned hypotheses, based on both probability and geographical approaches, in contrast to a conventional, random cluster selection strategy.

Does Self-Selection Affect Samples’ Representativeness in Online Surveys? An Investigation in Online Video Game Research

PubMed Central

van Singer, Mathias; Chatton, Anne; Achab, Sophia; Zullino, Daniele; Rothen, Stephane; Khan, Riaz; Billieux, Joel; Thorens, Gabriel

2014-01-01

Background The number of medical studies performed through online surveys has increased dramatically in recent years. Despite their numerous advantages (eg, sample size, facilitated access to individuals presenting stigmatizing issues), selection bias may exist in online surveys. However, evidence on the representativeness of self-selected samples in online studies is patchy. Objective Our objective was to explore the representativeness of a self-selected sample of online gamers using online players’ virtual characters (avatars). Methods All avatars belonged to individuals playing World of Warcraft (WoW), currently the most widely used online game. Avatars’ characteristics were defined using various games’ scores, reported on the WoW’s official website, and two self-selected samples from previous studies were compared with a randomly selected sample of avatars. Results We used scores linked to 1240 avatars (762 from the self-selected samples and 478 from the random sample). The two self-selected samples of avatars had higher scores on most of the assessed variables (except for guild membership and exploration). Furthermore, some guilds were overrepresented in the self-selected samples. Conclusions Our results suggest that more proficient players or players more involved in the game may be more likely to participate in online surveys. Caution is needed in the interpretation of studies based on online surveys that used a self-selection recruitment procedure. Epidemiological evidence on the reduced representativeness of sample of online surveys is warranted. PMID:25001007

Moving a randomized clinical trial into an observational cohort.

PubMed

Goodman, Phyllis J; Hartline, Jo Ann; Tangen, Catherine M; Crowley, John J; Minasian, Lori M; Klein, Eric A; Cook, Elise D; Darke, Amy K; Arnold, Kathryn B; Anderson, Karen; Yee, Monica; Meyskens, Frank L; Baker, Laurence H

2013-02-01

The Selenium and Vitamin E Cancer Prevention Trial (SELECT) was a randomized, double-blind, placebo-controlled prostate cancer prevention study funded by the National Cancer Institute (NCI) and conducted by the Southwest Oncology Group (SWOG). A total of 35,533 men were assigned randomly to one of the four treatment groups (vitamin E + placebo, selenium + placebo, vitamin E + selenium, and placebo + placebo). The independent Data and Safety Monitoring Committee (DSMC) recommended the discontinuation of study supplements because of the lack of efficacy for risk reduction and because futility analyses demonstrated no possibility of benefit of the supplements to the anticipated degree (25% reduction in prostate cancer incidence) with additional follow-up. Study leadership agreed that the randomized trial should be terminated but believed that the cohort should be maintained and followed as the additional follow-up would contribute important information to the understanding of the biologic consequences of the intervention. Since the participants no longer needed to be seen in person to assess acute toxicities or to be given study supplements, it was determined that the most efficient and cost-effective way to follow them was via a central coordinated effort. A number of changes were necessary at the local Study Sites and SELECT Statistical Center to transition to following participants via a Central Coordinating Center. We describe the transition process from a randomized clinical trial to the observational Centralized Follow-Up (CFU) study. The process of transitioning SELECT, implemented at more than 400 Study Sites across the United States, Canada, and Puerto Rico, entailed many critical decisions and actions including updates to online documents such as the SELECT Workbench and Study Manual, a protocol amendment, reorganization of the Statistical Center, creation of a Transition Committee, development of materials for SELECT Study Sites, development of procedures to close Study Sites, and revision of data collection procedures and the process by which to contact participants. At the time of the publication of the primary SELECT results in December 2008, there were 32,569 men alive and currently active in the trial. As of 31 December 2011, 17,761 participants had been registered to the CFU study. This number is less than had been anticipated due to unforeseen difficulties with local Study Site institutional review boards (IRBs). However, from this cohort, we estimate that an additional 580 prostate cancer cases and 215 Gleason 7 or higher grade cancers will be identified. Over 109,000 individual items have been mailed to participants. Active SELECT ancillary studies have continued. The substantial SELECT biorepository is available to researchers; requests to use the specimens are reviewed for feasibility and scientific merit. As of April 2012, 12 proposals had been approved. The accrual goal of the follow-up study was not met, limiting our power to address the study objectives satisfactorily. The CFU study is also dependent on a number of factors including continued funding, continued interest of investigators in the biorepository, and the continued contribution of the participants. Our experience may be less pertinent to investigators who wish to follow participants in a treatment trial or participants in prevention trials in other medical areas. Extended follow-up of participants in prevention research is important to study the long-term effects of the interventions, such as those used in SELECT. The approach taken by SELECT investigators was to continue to follow participants centrally via an annual questionnaire and with a web-based option. The participants enrolled in the CFU study represent a large, well-characterized, generally healthy cohort. The CFU has enabled us to collect additional prostate and other cancer endpoints and longer follow-up on the almost 18,000 participants enrolled. The utility of the extensive biorepository that was developed during the course of the SELECT is enhanced by longer follow-up.

Moving a Randomized Clinical Trial into an Observational Cohort

PubMed Central

Goodman, Phyllis J.; Hartline, Jo Ann; Tangen, Catherine M.; Crowley, John J.; Minasian, Lori M.; Klein, Eric A.; Cook, Elise D.; Darke, Amy K.; Arnold, Kathryn B.; Anderson, Karen; Yee, Monica; Meyskens, Frank L.; Baker, Laurence H.

2013-01-01

Background The Selenium and Vitamin E Cancer Prevention Trial (SELECT) was a randomized, double blind, placebo-controlled prostate cancer prevention study funded by the National Cancer Institute and conducted by SWOG (Southwest Oncology Group). A total of 35,533 men were assigned randomly to one of four treatment groups (vitamin E + placebo, selenium + placebo, vitamin E + selenium, placebo + placebo. The independent Data and Safety Monitoring Committee recommended the discontinuation of study supplements because of the lack of efficacy for risk reduction and because futility analyses demonstrated no possibility of benefit of the supplements to the anticipated degree (25% reduction in prostate cancer incidence) with additional follow-up. Study leadership agreed that the randomized trial should be terminated but believed that the cohort should be maintained and followed as the additional follow-up would contribute important information to the understanding of the biologic consequences of the intervention. Since the participants no longer needed to be seen in person to assess acute toxicities or to be given study supplements, it was determined that the most efficient and cost-effective way to follow them was via a central coordinated effort. Purpose A number of changes were necessary at the local Study Sites and SELECT Statistical Center to transition to following participants via a Central Coordinating Center. We describe the transition process from a randomized clinical trial to the observational Centralized Follow-up (CFU) study. Methods The process of transitioning SELECT, implemented at more than 400 Study Sites across the United States, Canada and Puerto Rico, entailed many critical decisions and actions including updates to online documents such as the SELECT Workbench and Study Manual, a protocol amendment, reorganization of the Statistical Center, creation of a Transition Committee, development of materials for SELECT Study Sites, development of procedures to close Study Sites, and revision of data collection procedures and the process by which to contact participants. Results At the time of the publication of the primary SELECT results in December 2008, there were 32,569 men alive and currently active in the trial. As of December 31, 2011, 17,761 participants had been registered to the CFU study. This number is less than had been anticipated due to unforeseen difficulties with local Study Site IRBs. However, from this cohort we estimate that an additional 580 prostate cancer cases and 215 Gleason 7 or higher cancers will be identified. Over 109,000 individual items have been mailed to participants. Active SELECT ancillary studies have continued. The substantial SELECT biorepository is available to researchers; requests to use the specimens are reviewed for feasibility and scientific merit. As of April 2012, 12 proposals had been approved. Limitations The accrual goal of the follow-up study was not met, limiting our power to address the study objectives satisfactorily. The CFU study is also dependent on a number of factors including continued funding, continued interest of investigators in the biorepository and the continued contribution of the participants. Our experience may be less pertinent to investigators who wish to follow participants in a treatment trial or participants in prevention trials in other medical areas. Conclusions Extended follow-up of participants in prevention research is important to study the long-term effects of the interventions, such as those used in SELECT. The approach taken by SELECT investigators was to continue to follow participants centrally via an annual questionnaire and with a web-based option. The participants enrolled in the CFU study represent a large, well-characterized, generally healthy cohort. The CFU has enabled us to collect additional prostate and other cancer endpoints and longer follow-up on the almost 18,000 participants enrolled. The utility of the extensive biorepository that was developed during the course of the SELECT is enhanced by longer follow-up. PMID:23064404

A large-scale cluster randomized trial to determine the effects of community-based dietary sodium reduction--the China Rural Health Initiative Sodium Reduction Study.

PubMed

Li, Nicole; Yan, Lijing L; Niu, Wenyi; Labarthe, Darwin; Feng, Xiangxian; Shi, Jingpu; Zhang, Jianxin; Zhang, Ruijuan; Zhang, Yuhong; Chu, Hongling; Neiman, Andrea; Engelgau, Michael; Elliott, Paul; Wu, Yangfeng; Neal, Bruce

2013-11-01

Cardiovascular diseases are the leading cause of death and disability in China. High blood pressure caused by excess intake of dietary sodium is widespread and an effective sodium reduction program has potential to improve cardiovascular health. This study is a large-scale, cluster-randomized, trial done in five Northern Chinese provinces. Two counties have been selected from each province and 12 townships in each county making a total of 120 clusters. Within each township one village has been selected for participation with 1:1 randomization stratified by county. The sodium reduction intervention comprises community health education and a food supply strategy based upon providing access to salt substitute. Subsidization of the price of salt substitute was done in 30 intervention villages selected at random. Control villages continued usual practices. The primary outcome for the study is dietary sodium intake level estimated from assays of 24-hour urine. The trial recruited and randomized 120 townships in April 2011. The sodium reduction program was commenced in the 60 intervention villages between May and June of that year with outcome surveys scheduled for October to December 2012. Baseline data collection shows that randomisation achieved good balance across groups. The establishment of the China Rural Health Initiative has enabled the launch of this large-scale trial designed to identify a novel, scalable strategy for reduction of dietary sodium and control of blood pressure. If proved effective, the intervention could plausibly be implemented at low cost in large parts of China and other countries worldwide. © 2013.

Optimal Item Selection with Credentialing Examinations.

ERIC Educational Resources Information Center

Hambleton, Ronald K.; And Others

The study compared two promising item response theory (IRT) item-selection methods, optimal and content-optimal, with two non-IRT item selection methods, random and classical, for use in fixed-length certification exams. The four methods were used to construct 20-item exams from a pool of approximately 250 items taken from a 1985 certification…

Genetic parameters for growth characteristics of free-range chickens under univariate random regression models.

PubMed

Rovadoscki, Gregori A; Petrini, Juliana; Ramirez-Diaz, Johanna; Pertile, Simone F N; Pertille, Fábio; Salvian, Mayara; Iung, Laiza H S; Rodriguez, Mary Ana P; Zampar, Aline; Gaya, Leila G; Carvalho, Rachel S B; Coelho, Antonio A D; Savino, Vicente J M; Coutinho, Luiz L; Mourão, Gerson B

2016-09-01

Repeated measures from the same individual have been analyzed by using repeatability and finite dimension models under univariate or multivariate analyses. However, in the last decade, the use of random regression models for genetic studies with longitudinal data have become more common. Thus, the aim of this research was to estimate genetic parameters for body weight of four experimental chicken lines by using univariate random regression models. Body weight data from hatching to 84 days of age (n = 34,730) from four experimental free-range chicken lines (7P, Caipirão da ESALQ, Caipirinha da ESALQ and Carijó Barbado) were used. The analysis model included the fixed effects of contemporary group (gender and rearing system), fixed regression coefficients for age at measurement, and random regression coefficients for permanent environmental effects and additive genetic effects. Heterogeneous variances for residual effects were considered, and one residual variance was assigned for each of six subclasses of age at measurement. Random regression curves were modeled by using Legendre polynomials of the second and third orders, with the best model chosen based on the Akaike Information Criterion, Bayesian Information Criterion, and restricted maximum likelihood. Multivariate analyses under the same animal mixed model were also performed for the validation of the random regression models. The Legendre polynomials of second order were better for describing the growth curves of the lines studied. Moderate to high heritabilities (h(2) = 0.15 to 0.98) were estimated for body weight between one and 84 days of age, suggesting that selection for body weight at all ages can be used as a selection criteria. Genetic correlations among body weight records obtained through multivariate analyses ranged from 0.18 to 0.96, 0.12 to 0.89, 0.06 to 0.96, and 0.28 to 0.96 in 7P, Caipirão da ESALQ, Caipirinha da ESALQ, and Carijó Barbado chicken lines, respectively. Results indicate that genetic gain for body weight can be achieved by selection. Also, selection for body weight at 42 days of age can be maintained as a selection criterion. © 2016 Poultry Science Association Inc.

Feature Selection for Chemical Sensor Arrays Using Mutual Information

PubMed Central

Wang, X. Rosalind; Lizier, Joseph T.; Nowotny, Thomas; Berna, Amalia Z.; Prokopenko, Mikhail; Trowell, Stephen C.

2014-01-01

We address the problem of feature selection for classifying a diverse set of chemicals using an array of metal oxide sensors. Our aim is to evaluate a filter approach to feature selection with reference to previous work, which used a wrapper approach on the same data set, and established best features and upper bounds on classification performance. We selected feature sets that exhibit the maximal mutual information with the identity of the chemicals. The selected features closely match those found to perform well in the previous study using a wrapper approach to conduct an exhaustive search of all permitted feature combinations. By comparing the classification performance of support vector machines (using features selected by mutual information) with the performance observed in the previous study, we found that while our approach does not always give the maximum possible classification performance, it always selects features that achieve classification performance approaching the optimum obtained by exhaustive search. We performed further classification using the selected feature set with some common classifiers and found that, for the selected features, Bayesian Networks gave the best performance. Finally, we compared the observed classification performances with the performance of classifiers using randomly selected features. We found that the selected features consistently outperformed randomly selected features for all tested classifiers. The mutual information filter approach is therefore a computationally efficient method for selecting near optimal features for chemical sensor arrays. PMID:24595058

A software system for the simulation of chest lesions

NASA Astrophysics Data System (ADS)

Ryan, John T.; McEntee, Mark; Barrett, Saoirse; Evanoff, Michael; Manning, David; Brennan, Patrick

2007-03-01

We report on the development of a novel software tool for the simulation of chest lesions. This software tool was developed for use in our study to attain optimal ambient lighting conditions for chest radiology. This study involved 61 consultant radiologists from the American Board of Radiology. Because of its success, we intend to use the same tool for future studies. The software has two main functions: the simulation of lesions and retrieval of information for ROC (Receiver Operating Characteristic) and JAFROC (Jack-Knife Free Response ROC) analysis. The simulation layer operates by randomly selecting an image from a bank of reportedly normal chest x-rays. A random location is then generated for each lesion, which is checked against a reference lung-map. If the location is within the lung fields, as derived from the lung-map, a lesion is superimposed. Lesions are also randomly selected from a bank of manually created chest lesion images. A blending algorithm determines which are the best intensity levels for the lesion to sit naturally within the chest x-ray. The same software was used to run a study for all 61 radiologists. A sequence of images is displayed in random order. Half of these images had simulated lesions, ranging from subtle to obvious, and half of the images were normal. The operator then selects locations where he/she thinks lesions exist and grades the lesion accordingly. We have found that this software was very effective in this study and intend to use the same principles for future studies.

Comparative study of feature selection with ensemble learning using SOM variants

NASA Astrophysics Data System (ADS)

Filali, Ameni; Jlassi, Chiraz; Arous, Najet

2017-03-01

Ensemble learning has succeeded in the growth of stability and clustering accuracy, but their runtime prohibits them from scaling up to real-world applications. This study deals the problem of selecting a subset of the most pertinent features for every cluster from a dataset. The proposed method is another extension of the Random Forests approach using self-organizing maps (SOM) variants to unlabeled data that estimates the out-of-bag feature importance from a set of partitions. Every partition is created using a various bootstrap sample and a random subset of the features. Then, we show that the process internal estimates are used to measure variable pertinence in Random Forests are also applicable to feature selection in unsupervised learning. This approach aims to the dimensionality reduction, visualization and cluster characterization at the same time. Hence, we provide empirical results on nineteen benchmark data sets indicating that RFS can lead to significant improvement in terms of clustering accuracy, over several state-of-the-art unsupervised methods, with a very limited subset of features. The approach proves promise to treat with very broad domains.

The need of adequate information to achieve total compliance of mass drug administration in Pekalongan

NASA Astrophysics Data System (ADS)

Ginandjar, Praba; Saraswati, Lintang Dian; Taufik, Opik; Nurjazuli; Widjanarko, Bagoes

2017-02-01

World Health Organization (WHO) initiated The Global Program to Eliminate Lymphatic Filariasis (LF) through mass drug administration (MDA). Pekalongan started MDA in 2011. Yet the LF prevalence in 2015 remained exceed the threshold (1%). This study aimed to describe the inhibiting factors related to the compliance of MDA in community level. This was a rapid survey with cross sectional approach. A two-stages random sampling was used in this study. In the first stage, 25 clusters were randomly selected from 27 villages with proportionate to population size (PPS) methods (C-Survey). In the second stage, 10 subjects were randomly selected from each cluster. Subject consisted of 250 respondents from 25 selected clusters. Variables consisted of MDA coverage, practice of taking medication during MDA, enabling and inhibiting factors to MDA in community level. The results showed most respondents had poor knowledge on filariasis, which influence awareness of the disease. Health-illness perception, did not receive the drugs, lactation, side effect, and size of the drugs were dominant factors of non-compliance to MDA. MDA information and community empowerment were needed to improve MDA coverage. Further study to explore the appropriate model of socialization will support the success of MDA program

A New Method of Random Environmental Walking for Assessing Behavioral Preferences for Different Lighting Applications

PubMed Central

Patching, Geoffrey R.; Rahm, Johan; Jansson, Märit; Johansson, Maria

2017-01-01

Accurate assessment of people’s preferences for different outdoor lighting applications is increasingly considered important in the development of new urban environments. Here a new method of random environmental walking is proposed to complement current methods of assessing urban lighting applications, such as self-report questionnaires. The procedure involves participants repeatedly walking between different lighting applications by random selection of a lighting application and preferred choice or by random selection of a lighting application alone. In this manner, participants are exposed to all lighting applications of interest more than once and participants’ preferences for the different lighting applications are reflected in the number of times they walk to each lighting application. On the basis of an initial simulation study, to explore the feasibility of this approach, a comprehensive field test was undertaken. The field test included random environmental walking and collection of participants’ subjective ratings of perceived pleasantness (PP), perceived quality, perceived strength, and perceived flicker of four lighting applications. The results indicate that random environmental walking can reveal participants’ preferences for different lighting applications that, in the present study, conformed to participants’ ratings of PP and perceived quality of the lighting applications. As a complement to subjectively stated environmental preferences, random environmental walking has the potential to expose behavioral preferences for different lighting applications. PMID:28337163

Assessing Nutrition Knowledge and Dietary Habits of Adolescents Using Personal Data Assistants

ERIC Educational Resources Information Center

Murimi, Mary W.; Guthrie, Joanne; Landry, Danielle; Paun, Mihaela M.

2008-01-01

Objective: To assess nutrition knowledge and dietary behaviors of seventh graders in nine randomly selected middle schools in Louisiana. Methods: This descriptive study used personal data assistants (PDAs) to administer a pre-validated questionnaire developed from national instruments to 127 seventh grade students from nine randomly-selected…

Improving ensemble decision tree performance using Adaboost and Bagging

NASA Astrophysics Data System (ADS)

Hasan, Md. Rajib; Siraj, Fadzilah; Sainin, Mohd Shamrie

2015-12-01

Ensemble classifier systems are considered as one of the most promising in medical data classification and the performance of deceision tree classifier can be increased by the ensemble method as it is proven to be better than single classifiers. However, in a ensemble settings the performance depends on the selection of suitable base classifier. This research employed two prominent esemble s namely Adaboost and Bagging with base classifiers such as Random Forest, Random Tree, j48, j48grafts and Logistic Model Regression (LMT) that have been selected independently. The empirical study shows that the performance varries when different base classifiers are selected and even some places overfitting issue also been noted. The evidence shows that ensemble decision tree classfiers using Adaboost and Bagging improves the performance of selected medical data sets.

Blood Selenium Concentration and Blood Cystatin C Concentration in a Randomly Selected Population of Healthy Children Environmentally Exposed to Lead and Cadmium.

PubMed

Gać, Paweł; Pawlas, Natalia; Wylężek, Paweł; Poręba, Rafał; Poręba, Małgorzata; Pawlas, Krystyna

2017-01-01

This study aimed at evaluation of a relationship between blood selenium concentration (Se-B) and blood cystatin C concentration (CST) in a randomly selected population of healthy children, environmentally exposed to lead and cadmium. The studies were conducted on 172 randomly selected children (7.98 ± 0.97 years). Among participants, the subgroups were distinguished, manifesting marginally low blood selenium concentration (Se-B 40-59 μg/l), suboptimal blood selenium concentration (Se-B: 60-79 μg/l) or optimal blood selenium concentration (Se-B ≥ 80 μg/l). At the subsequent stage, analogous subgroups of participants were selected separately in groups of children with BMI below median value (BMI <16.48 kg/m 2 ) and in children with BMI ≥ median value (BMI ≥16.48 kg/m 2 ). In all participants, values of Se-B and CST were estimated. In the entire group of examined children no significant differences in mean CST values were detected between groups distinguished on the base of normative Se-B values. Among children with BMI below 16.48 kg/m 2 , children with marginally low Se-B manifested significantly higher mean CST values, as compared to children with optimum Se-B (0.95 ± 0.07 vs. 0.82 ± 0.15 mg/l, p < 0.05). In summary, in a randomly selected population of healthy children no relationships could be detected between blood selenium concentration and blood cystatin C concentration. On the other hand, in children with low body mass index, a negative non-linear relationship was present between blood selenium concentration and blood cystatin C concentration.

Correcting Classifiers for Sample Selection Bias in Two-Phase Case-Control Studies

PubMed Central

Theis, Fabian J.

2017-01-01

Epidemiological studies often utilize stratified data in which rare outcomes or exposures are artificially enriched. This design can increase precision in association tests but distorts predictions when applying classifiers on nonstratified data. Several methods correct for this so-called sample selection bias, but their performance remains unclear especially for machine learning classifiers. With an emphasis on two-phase case-control studies, we aim to assess which corrections to perform in which setting and to obtain methods suitable for machine learning techniques, especially the random forest. We propose two new resampling-based methods to resemble the original data and covariance structure: stochastic inverse-probability oversampling and parametric inverse-probability bagging. We compare all techniques for the random forest and other classifiers, both theoretically and on simulated and real data. Empirical results show that the random forest profits from only the parametric inverse-probability bagging proposed by us. For other classifiers, correction is mostly advantageous, and methods perform uniformly. We discuss consequences of inappropriate distribution assumptions and reason for different behaviors between the random forest and other classifiers. In conclusion, we provide guidance for choosing correction methods when training classifiers on biased samples. For random forests, our method outperforms state-of-the-art procedures if distribution assumptions are roughly fulfilled. We provide our implementation in the R package sambia. PMID:29312464

A web-based appointment system to reduce waiting for outpatients: a retrospective study.

PubMed

Cao, Wenjun; Wan, Yi; Tu, Haibo; Shang, Fujun; Liu, Danhong; Tan, Zhijun; Sun, Caihong; Ye, Qing; Xu, Yongyong

2011-11-22

Long waiting times for registration to see a doctor is problematic in China, especially in tertiary hospitals. To address this issue, a web-based appointment system was developed for the Xijing hospital. The aim of this study was to investigate the efficacy of the web-based appointment system in the registration service for outpatients. Data from the web-based appointment system in Xijing hospital from January to December 2010 were collected using a stratified random sampling method, from which participants were randomly selected for a telephone interview asking for detailed information on using the system. Patients who registered through registration windows were randomly selected as a comparison group, and completed a questionnaire on-site. A total of 5641 patients using the online booking service were available for data analysis. Of them, 500 were randomly selected, and 369 (73.8%) completed a telephone interview. Of the 500 patients using the usual queuing method who were randomly selected for inclusion in the study, responses were obtained from 463, a response rate of 92.6%. Between the two registration methods, there were significant differences in age, degree of satisfaction, and total waiting time (P<0.001). However, gender, urban residence, and valid waiting time showed no significant differences (P>0.05). Being ignorant of online registration, not trusting the internet, and a lack of ability to use a computer were three main reasons given for not using the web-based appointment system. The overall proportion of non-attendance was 14.4% for those using the web-based appointment system, and the non-attendance rate was significantly different among different hospital departments, day of the week, and time of the day (P<0.001). Compared to the usual queuing method, the web-based appointment system could significantly increase patient's satisfaction with registration and reduce total waiting time effectively. However, further improvements are needed for broad use of the system.

From Protocols to Publications: A Study in Selective Reporting of Outcomes in Randomized Trials in Oncology

PubMed Central

Raghav, Kanwal Pratap Singh; Mahajan, Sminil; Yao, James C.; Hobbs, Brian P.; Berry, Donald A.; Pentz, Rebecca D.; Tam, Alda; Hong, Waun K.; Ellis, Lee M.; Abbruzzese, James; Overman, Michael J.

2015-01-01

Purpose The decision by journals to append protocols to published reports of randomized trials was a landmark event in clinical trial reporting. However, limited information is available on how this initiative effected transparency and selective reporting of clinical trial data. Methods We analyzed 74 oncology-based randomized trials published in Journal of Clinical Oncology, the New England Journal of Medicine, and The Lancet in 2012. To ascertain integrity of reporting, we compared published reports with their respective appended protocols with regard to primary end points, nonprimary end points, unplanned end points, and unplanned analyses. Results A total of 86 primary end points were reported in 74 randomized trials; nine trials had greater than one primary end point. Nine trials (12.2%) had some discrepancy between their planned and published primary end points. A total of 579 nonprimary end points (median, seven per trial) were planned, of which 373 (64.4%; median, five per trial) were reported. A significant positive correlation was found between the number of planned and nonreported nonprimary end points (Spearman r = 0.66; P < .001). Twenty-eight studies (37.8%) reported a total of 65 unplanned end points; 52 (80.0%) of which were not identified as unplanned. Thirty-one (41.9%) and 19 (25.7%) of 74 trials reported a total of 52 unplanned analyses involving primary end points and 33 unplanned analyses involving nonprimary end points, respectively. Studies reported positive unplanned end points and unplanned analyses more frequently than negative outcomes in abstracts (unplanned end points odds ratio, 6.8; P = .002; unplanned analyses odd ratio, 8.4; P = .007). Conclusion Despite public and reviewer access to protocols, selective outcome reporting persists and is a major concern in the reporting of randomized clinical trials. To foster credible evidence-based medicine, additional initiatives are needed to minimize selective reporting. PMID:26304898

Effective Teaching with ICT in Nigerian Higher Institutions: A Solution to Graduates' Unemployability

ERIC Educational Resources Information Center

Femi, Sunday Akinwumi; Yemisi, Etomi Edwin

2015-01-01

This study investigated effective teaching with the aid of ICT in Nigerian higher education institutions as a proposed solution to graduates' unemployability. The survey method was utilized for this study. Respondents were randomly selected from students and teachers of selected higher institutions in Nigeria. The findings reveal that, even though…

A randomized controlled trial of an electronic informed consent process.

PubMed

Rothwell, Erin; Wong, Bob; Rose, Nancy C; Anderson, Rebecca; Fedor, Beth; Stark, Louisa A; Botkin, Jeffrey R

2014-12-01

A pilot study assessed an electronic informed consent model within a randomized controlled trial (RCT). Participants who were recruited for the parent RCT project were randomly selected and randomized to either an electronic consent group (n = 32) or a simplified paper-based consent group (n = 30). Results from the electronic consent group reported significantly higher understanding of the purpose of the study, alternatives to participation, and who to contact if they had questions or concerns about the study. However, participants in the paper-based control group reported higher mean scores on some survey items. This research suggests that an electronic informed consent presentation may improve participant understanding for some aspects of a research study. © The Author(s) 2014.

Randomization in clinical trials in orthodontics: its significance in research design and methods to achieve it.

PubMed

Pandis, Nikolaos; Polychronopoulou, Argy; Eliades, Theodore

2011-12-01

Randomization is a key step in reducing selection bias during the treatment allocation phase in randomized clinical trials. The process of randomization follows specific steps, which include generation of the randomization list, allocation concealment, and implementation of randomization. The phenomenon in the dental and orthodontic literature of characterizing treatment allocation as random is frequent; however, often the randomization procedures followed are not appropriate. Randomization methods assign, at random, treatment to the trial arms without foreknowledge of allocation by either the participants or the investigators thus reducing selection bias. Randomization entails generation of random allocation, allocation concealment, and the actual methodology of implementing treatment allocation randomly and unpredictably. Most popular randomization methods include some form of restricted and/or stratified randomization. This article introduces the reasons, which make randomization an integral part of solid clinical trial methodology, and presents the main randomization schemes applicable to clinical trials in orthodontics.

Cavity tree selection by red-cockaded woodpeckers in relation to tree age

Treesearch

D. Craig Rudolph; Richard N. Conner

1991-01-01

We aged over 1350 Red-cockaded Woodpecker (Picoides borealis) cavity trees and a comparable number of randomly selected trees. Resulting data strongly support the hypothesis that Red-cockaded Woodpeckers preferentially select older trees. Ages of recently initiated cavity trees in the Texas study areas generally were similar to those of cavity trees...

Selected Health Practices Among Ohio's Rural Residents.

ERIC Educational Resources Information Center

Phillips, G. Howard; Pugh, Albert

Using a stratified random sample of 12 of Ohio's 88 counties, this 1967 study had as its objectives (1) to measure the level of participation in selected health practices by Ohio's rural residents, (2) to compare the level of participation in selected health practices of farm and rural nonfarm residents, and (3) to examine levels of participation…

Development of Multiple Regression Equations To Predict Fourth Graders' Achievement in Reading and Selected Content Areas.

ERIC Educational Resources Information Center

Hafner, Lawrence E.

A study developed a multiple regression prediction equation for each of six selected achievement variables in a popular standardized test of achievement. Subjects, 42 fourth-grade pupils randomly selected across several classes in a large elementary school in a north Florida city, were administered several standardized tests to determine predictor…

Does Mother Know Best? Treatment Adherence as a Function of Anticipated Treatment Benefit

PubMed Central

Glymour, M. Maria; Nguyen, Quynh; Matsouaka, Roland; Tchetgen Tchetgen, Eric J.; Schmidt, Nicole M.; Osypuk, Theresa L.

2016-01-01

Background We describe bias resulting from individualized treatment selection, which occurs when treatment has heterogeneous effects and individuals selectively choose treatments of greatest benefit to themselves. This pernicious bias may confound estimates from observational studies and lead to important misinterpretation of intent-to-treat analyses of randomized trials. Despite the potentially serious threat to inferences, individualized treatment selection has rarely been formally described or assessed. Methods The Moving to Opportunity (MTO) trial randomly assigned subsidized rental vouchers to low-income families in high-poverty public housing. We assessed the Kessler-6 psychological distress and Behavior Problems Index outcomes for 2,829 adolescents 4–7 years after randomization. Among families randomly assigned to receive vouchers, we estimated probability of moving (treatment), predicted by pre-randomization characteristics (c-statistic=0.63). We categorized families into tertiles of this estimated probability of moving, and compared instrumental variable effect estimates for moving on Behavior Problems Index and Kessler-6 across tertiles. Results Instrumental variable estimated effects of moving on behavioral problems index were most adverse for boys least likely to move (b=0.93; 95% CI: 0.33, 1.53) compared to boys most likely to move (b=0.14; 95% CI: −0.15, 0.44; p=.02 for treatment*tertile interaction). Effects on Kessler-6 were more beneficial for girls least likely to move compared to girls most likely to move (−0.62 vs. 0.02; interaction p=.03). Conclusions Evidence of Individualized treatment selection differed by child gender and outcome and should be evaluated in randomized trial reports, especially when heterogeneous treatment effects are likely and non-adherence is common. PMID:26628424

Neither fixed nor random: weighted least squares meta-regression.

PubMed

Stanley, T D; Doucouliagos, Hristos

2017-03-01

Our study revisits and challenges two core conventional meta-regression estimators: the prevalent use of 'mixed-effects' or random-effects meta-regression analysis and the correction of standard errors that defines fixed-effects meta-regression analysis (FE-MRA). We show how and explain why an unrestricted weighted least squares MRA (WLS-MRA) estimator is superior to conventional random-effects (or mixed-effects) meta-regression when there is publication (or small-sample) bias that is as good as FE-MRA in all cases and better than fixed effects in most practical applications. Simulations and statistical theory show that WLS-MRA provides satisfactory estimates of meta-regression coefficients that are practically equivalent to mixed effects or random effects when there is no publication bias. When there is publication selection bias, WLS-MRA always has smaller bias than mixed effects or random effects. In practical applications, an unrestricted WLS meta-regression is likely to give practically equivalent or superior estimates to fixed-effects, random-effects, and mixed-effects meta-regression approaches. However, random-effects meta-regression remains viable and perhaps somewhat preferable if selection for statistical significance (publication bias) can be ruled out and when random, additive normal heterogeneity is known to directly affect the 'true' regression coefficient. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Effects of Teaching a Library Usage Unit to Seventh Graders.

ERIC Educational Resources Information Center

Gifford, Vernon; Gifford, Jean

This document reports the results of a study undertaken to determine if teaching a 2-week unit on library usage to 7th graders would increase their use of the library. From three non-ability grouped 7th grade classes, two classes of 26 students each were randomly selected for the study. One class was randomly assigned as the experimental group and…

A Randomized, Double-Blind, Crossover Comparison of MK-0929 and Placebo in the Treatment of Adults with ADHD

ERIC Educational Resources Information Center

Rivkin, Anna; Alexander, Robert C.; Knighton, Jennifer; Hutson, Pete H.; Wang, Xiaojing J.; Snavely, Duane B.; Rosah, Thomas; Watt, Alan P.; Reimherr, Fred W.; Adler, Lenard A.

2012-01-01

Objective: Preclinical models, receptor localization, and genetic linkage data support the role of D4 receptors in the etiology of ADHD. This proof-of-concept study was designed to evaluate MK-0929, a selective D4 receptor antagonist as treatment for adult ADHD. Method: A randomized, double-blind, placebo-controlled, crossover study was conducted…

In vitro selection of catalytic RNAs

NASA Technical Reports Server (NTRS)

Chapman, K. B.; Szostak, J. W.

1994-01-01

In vitro selection techniques are poised to allow a rapid expansion of the study of catalysis by RNA enzymes (ribozymes). This truly molecular version of genetics has already been applied to the study of the structures of known ribozymes and to the tailoring of their catalytic activity to meet specific requirements of substrate specificity or reaction conditions. During the past year, in vitro selection has been successfully used to isolate novel RNA catalysts from random sequence pools.

Determinants of selective reporting: A taxonomy based on content analysis of a random selection of the literature

PubMed Central

van den Bogert, Cornelis A.; van Soest-Poortvliet, Mirjam C.; Fazeli Farsani, Soulmaz; Otten, René H. J.; ter Riet, Gerben; Bouter, Lex M.

2018-01-01

Background Selective reporting is wasteful, leads to bias in the published record and harms the credibility of science. Studies on potential determinants of selective reporting currently lack a shared taxonomy and a causal framework. Objective To develop a taxonomy of determinants of selective reporting in science. Design Inductive qualitative content analysis of a random selection of the pertinent literature including empirical research and theoretical reflections. Methods Using search terms for bias and selection combined with terms for reporting and publication, we systematically searched the PubMed, Embase, PsycINFO and Web of Science databases up to January 8, 2015. Of the 918 articles identified, we screened a 25 percent random selection. From eligible articles, we extracted phrases that mentioned putative or possible determinants of selective reporting, which we used to create meaningful categories. We stopped when no new categories emerged in the most recently analyzed articles (saturation). Results Saturation was reached after analyzing 64 articles. We identified 497 putative determinants, of which 145 (29%) were supported by empirical findings. The determinants represented 12 categories (leaving 3% unspecified): focus on preferred findings (36%), poor or overly flexible research design (22%), high-risk area and its development (8%), dependence upon sponsors (8%), prejudice (7%), lack of resources including time (3%), doubts about reporting being worth the effort (3%), limitations in reporting and editorial practices (3%), academic publication system hurdles (3%), unfavorable geographical and regulatory environment (2%), relationship and collaboration issues (2%), and potential harm (0.4%). Conclusions We designed a taxonomy of putative determinants of selective reporting consisting of 12 categories. The taxonomy may help develop theory about causes of selection bias and guide policies to prevent selective reporting. PMID:29401492

A LARGE-SCALE CLUSTER RANDOMIZED TRIAL TO DETERMINE THE EFFECTS OF COMMUNITY-BASED DIETARY SODIUM REDUCTION – THE CHINA RURAL HEALTH INITIATIVE SODIUM REDUCTION STUDY

PubMed Central

Li, Nicole; Yan, Lijing L.; Niu, Wenyi; Labarthe, Darwin; Feng, Xiangxian; Shi, Jingpu; Zhang, Jianxin; Zhang, Ruijuan; Zhang, Yuhong; Chu, Hongling; Neiman, Andrea; Engelgau, Michael; Elliott, Paul; Wu, Yangfeng; Neal, Bruce

2013-01-01

Background Cardiovascular diseases are the leading cause of death and disability in China. High blood pressure caused by excess intake of dietary sodium is widespread and an effective sodium reduction program has potential to improve cardiovascular health. Design This study is a large-scale, cluster-randomized, trial done in five Northern Chinese provinces. Two counties have been selected from each province and 12 townships in each county making a total of 120 clusters. Within each township one village has been selected for participation with 1:1 randomization stratified by county. The sodium reduction intervention comprises community health education and a food supply strategy based upon providing access to salt substitute. Subsidization of the price of salt substitute was done in 30 intervention villages selected at random. Control villages continued usual practices. The primary outcome for the study is dietary sodium intake level estimated from assays of 24 hour urine. Trial status The trial recruited and randomized 120 townships in April 2011. The sodium reduction program was commenced in the 60 intervention villages between May and June of that year with outcome surveys scheduled for October to December 2012. Baseline data collection shows that randomisation achieved good balance across groups. Discussion The establishment of the China Rural Health Initiative has enabled the launch of this large-scale trial designed to identify a novel, scalable strategy for reduction of dietary sodium and control of blood pressure. If proved effective, the intervention could plausibly be implemented at low cost in large parts of China and other countries worldwide. PMID:24176436

Gain in Student Understanding of the Role of Random Variation in Evolution Following Teaching Intervention Based on Luria-Delbruck Experiment†

PubMed Central

Robson, Rachel L.; Burns, Susan

2011-01-01

Undergraduate students in introductory biology classes are typically saddled with pre-existing popular beliefs that impede their ability to learn about biological evolution. One of the most common misconceptions about evolution is that the environment causes advantageous mutations, rather than the correct view that mutations occur randomly and the environment only selects for mutants with advantageous traits. In this study, a significant gain in student understanding of the role of randomness in evolution was observed after students participated in an inquiry-based pedagogical intervention based on the Luria-Delbruck experiment. Questionnaires with isomorphic questions regarding environmental selection among random mutants were administered to study participants (N = 82) in five separate sections of a sophomore-level microbiology class before and after the teaching intervention. Demographic data on each participant was also collected, in a way that preserved anonymity. Repeated measures analysis showed that post-test scores were significantly higher than pre-test scores with regard to the questions about evolution (F(1, 77) = 25.913, p < 0.001). Participants’ pre-existing beliefs about evolution had no significant effect on gain in understanding of this concept. This study indicates that conducting and discussing an experiment about phage resistance in E. coli may improve student understanding of the role of stochastic events in evolution more broadly, as post-test answers showed that students were able to apply the lesson of the Luria-Delbruck experiment to other organisms subjected to other kinds of selection. PMID:23653732

The G matrix under fluctuating correlational mutation and selection.

PubMed

Revell, Liam J

2007-08-01

Theoretical quantitative genetics provides a framework for reconstructing past selection and predicting future patterns of phenotypic differentiation. However, the usefulness of the equations of quantitative genetics for evolutionary inference relies on the evolutionary stability of the additive genetic variance-covariance matrix (G matrix). A fruitful new approach for exploring the evolutionary dynamics of G involves the use of individual-based computer simulations. Previous studies have focused on the evolution of the eigenstructure of G. An alternative approach employed in this paper uses the multivariate response-to-selection equation to evaluate the stability of G. In this approach, I measure similarity by the correlation between response-to-selection vectors due to random selection gradients. I analyze the dynamics of G under several conditions of correlational mutation and selection. As found in a previous study, the eigenstructure of G is stabilized by correlational mutation and selection. However, over broad conditions, instability of G did not result in a decreased consistency of the response to selection. I also analyze the stability of G when the correlation coefficients of correlational mutation and selection and the effective population size change through time. To my knowledge, no prior study has used computer simulations to investigate the stability of G when correlational mutation and selection fluctuate. Under these conditions, the eigenstructure of G is unstable under some simulation conditions. Different results are obtained if G matrix stability is assessed by eigenanalysis or by the response to random selection gradients. In this case, the response to selection is most consistent when certain aspects of the eigenstructure of G are least stable and vice versa.

The Role of Religiosity in Influencing Adolescent and Adult Alcohol Use in Trinidad

ERIC Educational Resources Information Center

Rollocks, Steve C. T.; Dass, Natasha; Seepersad, Randy; Mohammed, Linda

2008-01-01

This study examined the role of religiosity among adolescents' and adults' alcohol use in Trinidad. A stratified random sample design of 369 adolescents and 210 adult parents belonging to the various religious groups in Trinidad was employed. Participants were randomly selected from various educational districts across Trinidad. Adolescent…

Emotional Intelligence and Life Adjustment for Nigerian Secondary Students

ERIC Educational Resources Information Center

Ogoemeka, Obioma Helen

2013-01-01

In the process of educating adolescents, good emotional development and life adjustment are two significant factors for teachers to know. This study employed random cluster sampling of senior secondary school students in Ondo and Oyo States in south-western Nigeria. The Random sampling was employed to select 1,070 students. The data collected were…

78 FR 54653 - Proposed Data Collections Submitted for Public Comment and Recommendations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-05

... materials on opinions about CRC screening tests. Each respondent will be randomly assigned to one of three... treatment group that receives a ``No Excuses'' educational flyer designed to dispel many common reasons for... randomly selected from the KN KnowledgePanel[supreg]. A pre-test of study procedures will be conducted...

Age-related Cataract in a Randomized Trial of Selenium and Vitamin E in Men: The SELECT Eye Endpoints (SEE) Study

PubMed Central

Christen, William G.; Glynn, Robert J.; Gaziano, J. Michael; Darke, Amy K.; Crowley, John J.; Goodman, Phyllis J.; Lippman, Scott M.; Lad, Thomas E.; Bearden, James D.; Goodman, Gary E.; Minasian, Lori M.; Thompson, Ian M.; Blanke, Charles D.; Klein, Eric A.

2014-01-01

Importance Observational studies suggest a role for dietary nutrients such as vitamin E and selenium in cataract prevention. However, the results of randomized trials of vitamin E supplements and cataract have been disappointing, and are not yet available for selenium. Objective To test whether long-term supplementation with selenium and vitamin E affects the incidence of cataract in a large cohort of men. Design, Setting, and Participants The SELECT Eye Endpoints (SEE) study was an ancillary study of the SWOG-coordinated Selenium and Vitamin E Cancer Prevention Trial (SELECT), a randomized, placebo-controlled, four arm trial of selenium and vitamin E conducted among 35,533 men aged 50 years and older for African Americans and 55 and older for all other men, at 427 participating sites in the US, Canada, and Puerto Rico. A total of 11,267 SELECT participants from 128 SELECT sites participated in the SEE ancillary study. Intervention Individual supplements of selenium (200 µg/d from L-selenomethionine) and vitamin E (400 IU/d of all rac-α-tocopheryl acetate). Main Outcome Measures Incident cataract, defined as a lens opacity, age-related in origin, responsible for a reduction in best-corrected visual acuity to 20/30 or worse based on self-report confirmed by medical record review, and cataract extraction, defined as the surgical removal of an incident cataract. Results During a mean (SD) of 5.6 (1.2) years of treatment and follow-up, 389 cases of cataract were documented. There were 185 cataracts in the selenium group and 204 in the no selenium group (hazard ratio [HR], 0.91; 95 percent confidence interval [CI], 0.75 to 1.11; P=.37). For vitamin E, there were 197 cases in the treated group and 192 in the placebo group (HR, 1.02; CI, 0.84 to 1.25; P=.81). Similar results were observed for cataract extraction. Conclusions and Relevance These randomized trial data from a large cohort of apparently healthy men indicate that long-term daily supplementation with selenium and/or vitamin E is unlikely to have a large beneficial effect on age-related cataract. PMID:25232809

School Psychologists' Continuing Professional Development Preferences and Practices

ERIC Educational Resources Information Center

Armistead, Leigh D.; Castillo, Jose M.; Curtis, Michael J.; Chappel, Ashley; Cunningham, Jennifer

2013-01-01

This study investigated school psychologists' continuing professional development (CPD) activities, topics, needs, motivations, financial expenditures, and opinions, as well as relationships between select demographic characteristics and certain CPD practices and preferences. A survey was mailed to 1,000 randomly selected Regular Members of…

Systematic Evaluation of the Dependence of Deoxyribozyme Catalysis on Random Region Length

PubMed Central

Velez, Tania E.; Singh, Jaydeep; Xiao, Ying; Allen, Emily C.; Wong, On Yi; Chandra, Madhavaiah; Kwon, Sarah C.; Silverman, Scott K.

2012-01-01

Functional nucleic acids are DNA and RNA aptamers that bind targets, or they are deoxyribozymes and ribozymes that have catalytic activity. These functional DNA and RNA sequences can be identified from random-sequence pools by in vitro selection, which requires choosing the length of the random region. Shorter random regions allow more complete coverage of sequence space but may not permit the structural complexity necessary for binding or catalysis. In contrast, longer random regions are sampled incompletely but may allow adoption of more complicated structures that enable function. In this study, we systematically examined random region length (N20 through N60) for two particular deoxyribozyme catalytic activities, DNA cleavage and tyrosine-RNA nucleopeptide linkage formation. For both activities, we previously identified deoxyribozymes using only N40 regions. In the case of DNA cleavage, here we found that shorter N20 and N30 regions allowed robust catalytic function, either by DNA hydrolysis or by DNA deglycosylation and strand scission via β-elimination, whereas longer N50 and N60 regions did not lead to catalytically active DNA sequences. Follow-up selections with N20, N30, and N40 regions revealed an interesting interplay of metal ion cofactors and random region length. Separately, for Tyr-RNA linkage formation, N30 and N60 regions provided catalytically active sequences, whereas N20 was unsuccessful, and the N40 deoxyribozymes were functionally superior (in terms of rate and yield) to N30 and N60. Collectively, the results indicate that with future in vitro selection experiments for DNA and RNA catalysts, and by extension for aptamers, random region length should be an important experimental variable. PMID:23088677

Just-in-time consent: The ethical case for an alternative to traditional informed consent in randomized trials comparing an experimental intervention with usual care.

PubMed

Vickers, Andrew J; Young-Afat, Danny A; Ehdaie, Behfar; Kim, Scott Yh

2018-02-01

Informed consent for randomized trials often causes significant and persistent anxiety, distress and confusion to patients. Where an experimental treatment is compared to a standard care control, much of this burden is potentially avoidable in the control group. We propose a "just-in-time" consent in which consent discussions take place in two stages: an initial consent to research from all participants and a later specific consent to randomized treatment only from those assigned to the experimental intervention. All patients are first approached and informed about research procedures, such as questionnaires or tests. They are also informed that they might be randomly selected to receive an experimental treatment and that, if selected, they can learn more about the treatment and decide whether or not to accept it at that time. After randomization, control patients undergo standard clinical consent whereas patients randomized to the experimental procedure undergo a second consent discussion. Analysis would be by intent-to-treat, which protects the trial from selection bias, although not from poor acceptance of experimental treatment. The advantages of just-in-time consent stem from the fact that only patients randomized to the experimental treatment are subject to a discussion of that intervention. We hypothesize that this will reduce much of the patient's burden associated with the consent process, such as decisional anxiety, confusion and information overload. We recommend well-controlled studies to compare just-in-time and traditional consent, with endpoints to include characteristics of participants, distress and anxiety and participants' understanding of research procedures.

Socio-Economic Background and Access to Internet as Correlates of Students' Achievement in Agricultural Science

ERIC Educational Resources Information Center

Adegoke, Sunday Paul; Osokoya, Modupe M.

2015-01-01

This study investigated access to internet and socio-economic background as correlates of students' achievement in Agricultural Science among selected Senior Secondary Schools Two Students in Ogbomoso South and North Local Government Areas. The study adopted multi-stage sampling technique. Simple random sampling was used to select 30 students from…

Eliminating Survivor Bias in Two-stage Instrumental Variable Estimators.

PubMed

Vansteelandt, Stijn; Walter, Stefan; Tchetgen Tchetgen, Eric

2018-07-01

Mendelian randomization studies commonly focus on elderly populations. This makes the instrumental variables analysis of such studies sensitive to survivor bias, a type of selection bias. A particular concern is that the instrumental variable conditions, even when valid for the source population, may be violated for the selective population of individuals who survive the onset of the study. This is potentially very damaging because Mendelian randomization studies are known to be sensitive to bias due to even minor violations of the instrumental variable conditions. Interestingly, the instrumental variable conditions continue to hold within certain risk sets of individuals who are still alive at a given age when the instrument and unmeasured confounders exert additive effects on the exposure, and moreover, the exposure and unmeasured confounders exert additive effects on the hazard of death. In this article, we will exploit this property to derive a two-stage instrumental variable estimator for the effect of exposure on mortality, which is insulated against the above described selection bias under these additivity assumptions.

An Overview of Randomization and Minimization Programs for Randomized Clinical Trials

PubMed Central

Saghaei, Mahmoud

2011-01-01

Randomization is an essential component of sound clinical trials, which prevents selection biases and helps in blinding the allocations. Randomization is a process by which subsequent subjects are enrolled into trial groups only by chance, which essentially eliminates selection biases. A serious consequence of randomization is severe imbalance among the treatment groups with respect to some prognostic factors, which invalidate the trial results or necessitate complex and usually unreliable secondary analysis to eradicate the source of imbalances. Minimization on the other hand tends to allocate in such a way as to minimize the differences among groups, with respect to prognostic factors. Pure minimization is therefore completely deterministic, that is, one can predict the allocation of the next subject by knowing the factor levels of a previously enrolled subject and having the properties of the next subject. To eliminate the predictability of randomization, it is necessary to include some elements of randomness in the minimization algorithms. In this article brief descriptions of randomization and minimization are presented followed by introducing selected randomization and minimization programs. PMID:22606659

Prevalence of Dental Fear and Anxiety amongst Patients in Selected Dental Clinics in Ghana

ERIC Educational Resources Information Center

Ofori, Marian A.; Adu-Ababio, F.; Nyako, E. A.; Ndanu, Tom A.

2009-01-01

Objective: To find out the prevalence of dental anxiety and fear amongst patients in various selected dental clinics in Accra, Ghana. Study design: Dental patients (n = 279) who had either been exposed to dental treatments or had no prior dental exposure, attending four selected dental clinics in Accra were randomly sampled. They were interviewed…

Use of the "Intervention Selection Profile-Social Skills" to Identify Social Skill Acquisition Deficits: A Preliminary Validation Study

ERIC Educational Resources Information Center

Kilgus, Stephen P.; von der Embse, Nathaniel P.; Scott, Katherine; Paxton, Sara

2015-01-01

The purpose of this investigation was to develop and initially validate the "Intervention Selection Profile-Social Skills" (ISP-SS), a novel brief social skills assessment method intended for use at Tier 2. Participants included 54 elementary school teachers and their 243 randomly selected students. Teachers rated students on two rating…

To Let Students Self-Select or Not: That Is the Question for Teachers of Culturally Diverse Groups

ERIC Educational Resources Information Center

Rienties, Bart; Alcott, Peter; Jindal-Snape, Divya

2014-01-01

When students can self-select their group members, a common assumption is that students prefer to select friends from similar cultural backgrounds. However, when teachers randomize students in groups from different cultural backgrounds, students are "forced" to work together. The prime goal of this study is to understand the impact of…

Combined universal and selective prevention for adolescent alcohol use: a cluster randomized controlled trial.

PubMed

Teesson, M; Newton, N C; Slade, T; Carragher, N; Barrett, E L; Champion, K E; Kelly, E V; Nair, N K; Stapinski, L A; Conrod, P J

2017-07-01

No existing models of alcohol prevention concurrently adopt universal and selective approaches. This study aims to evaluate the first combined universal and selective approach to alcohol prevention. A total of 26 Australian schools with 2190 students (mean age: 13.3 years) were randomized to receive: universal prevention (Climate Schools); selective prevention (Preventure); combined prevention (Climate Schools and Preventure; CAP); or health education as usual (control). Primary outcomes were alcohol use, binge drinking and alcohol-related harms at 6, 12 and 24 months. Climate, Preventure and CAP students demonstrated significantly lower growth in their likelihood to drink and binge drink, relative to controls over 24 months. Preventure students displayed significantly lower growth in their likelihood to experience alcohol harms, relative to controls. While adolescents in both the CAP and Climate groups demonstrated slower growth in drinking compared with adolescents in the control group over the 2-year study period, CAP adolescents demonstrated faster growth in drinking compared with Climate adolescents. Findings support universal, selective and combined approaches to alcohol prevention. Particularly novel are the findings of no advantage of the combined approach over universal or selective prevention alone.

The RANDOM computer program: A linear congruential random number generator

NASA Technical Reports Server (NTRS)

Miles, R. F., Jr.

1986-01-01

The RANDOM Computer Program is a FORTRAN program for generating random number sequences and testing linear congruential random number generators (LCGs). The linear congruential form of random number generator is discussed, and the selection of parameters of an LCG for a microcomputer described. This document describes the following: (1) The RANDOM Computer Program; (2) RANDOM.MOD, the computer code needed to implement an LCG in a FORTRAN program; and (3) The RANCYCLE and the ARITH Computer Programs that provide computational assistance in the selection of parameters for an LCG. The RANDOM, RANCYCLE, and ARITH Computer Programs are written in Microsoft FORTRAN for the IBM PC microcomputer and its compatibles. With only minor modifications, the RANDOM Computer Program and its LCG can be run on most micromputers or mainframe computers.

Wildfire Selectivity for Land Cover Type: Does Size Matter?

PubMed Central

Barros, Ana M. G.; Pereira, José M. C.

2014-01-01

Previous research has shown that fires burn certain land cover types disproportionally to their abundance. We used quantile regression to study land cover proneness to fire as a function of fire size, under the hypothesis that they are inversely related, for all land cover types. Using five years of fire perimeters, we estimated conditional quantile functions for lower (avoidance) and upper (preference) quantiles of fire selectivity for five land cover types - annual crops, evergreen oak woodlands, eucalypt forests, pine forests and shrublands. The slope of significant regression quantiles describes the rate of change in fire selectivity (avoidance or preference) as a function of fire size. We used Monte-Carlo methods to randomly permutate fires in order to obtain a distribution of fire selectivity due to chance. This distribution was used to test the null hypotheses that 1) mean fire selectivity does not differ from that obtained by randomly relocating observed fire perimeters; 2) that land cover proneness to fire does not vary with fire size. Our results show that land cover proneness to fire is higher for shrublands and pine forests than for annual crops and evergreen oak woodlands. As fire size increases, selectivity decreases for all land cover types tested. Moreover, the rate of change in selectivity with fire size is higher for preference than for avoidance. Comparison between observed and randomized data led us to reject both null hypotheses tested ( = 0.05) and to conclude it is very unlikely the observed values of fire selectivity and change in selectivity with fire size are due to chance. PMID:24454747

Is intracytoplasmic morphologically selected sperm injection (IMSI) beneficial in the first ART cycle? a multicentric randomized controlled trial.

PubMed

Leandri, R D; Gachet, A; Pfeffer, J; Celebi, C; Rives, N; Carre-Pigeon, F; Kulski, O; Mitchell, V; Parinaud, J

2013-09-01

Intracytoplasmic morphologically selected sperm injection (IMSI), by selecting spermatozoa at high magnification improves the outcome of intracytoplasmic sperm injection (ICSI) mainly after several failures. However, only few monocentric randomized studies are available and they do not analyse results as a function of sperm characteristics. In 255 couples attempting their first assisted reproductive technology (ART) attempt for male infertility (motile sperm count <1×10⁶ after sperm selection, but at least 3×10⁶ spermatozoa per ejaculate to allow a detailed analysis of sperm characteristics), a prospective randomized trial was performed to compare the clinical outcomes of IMSI and ICSI and to evaluate the influence of sperm characteristics on these outcomes. IMSI did not provide any significant improvement in the clinical outcomes compared with ICSI neither for implantation (24% vs. 23%), nor clinical pregnancy (31% vs. 33%) nor live birth rates (27% vs. 30%). Moreover, the results of IMSI were similar to the ICSI ones whatever the degree of sperm DNA fragmentation, nuclear immaturity and sperm morphology. These results show that IMSI instead of ICSI has no advantage in the first ART attempts. However, this does not rule out IMSI completely and more randomized trials must be performed especially regarding patients carrying severe teratozoospermia, or high sperm DNA fragmentation levels or having previous ICSI failures. © 2013 American Society of Andrology and European Academy of Andrology.

Group Counseling With Emotionally Disturbed School Children in Taiwan.

ERIC Educational Resources Information Center

Chiu, Peter

The application of group counseling to emotionally disturbed school children in Chinese culture was examined. Two junior high schools located in Tao-Yuan Province were randomly selected with two eighth-grade classes randomly selected from each school. Ten emotionally disturbed students were chosen from each class and randomly assigned to two…

Sample Selection in Randomized Experiments: A New Method Using Propensity Score Stratified Sampling

ERIC Educational Resources Information Center

Tipton, Elizabeth; Hedges, Larry; Vaden-Kiernan, Michael; Borman, Geoffrey; Sullivan, Kate; Caverly, Sarah

2014-01-01

Randomized experiments are often seen as the "gold standard" for causal research. Despite the fact that experiments use random assignment to treatment conditions, units are seldom selected into the experiment using probability sampling. Very little research on experimental design has focused on how to make generalizations to well-defined…

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

ERIC Educational Resources Information Center

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

2017-01-01

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

Influence of Learning Environment on Students' Academic Achievement in Mathematics: A Case Study of Some Selected Secondary Schools in Yobe State-Nigeria

ERIC Educational Resources Information Center

Shamaki, Timothy Ado

2015-01-01

The purpose of the study was to determine the influence of learning environment on students' academic achievement in mathematics at senior secondary school level. Thus the study investigated some components of learning environment and their possible influence on students' academic achievement in mathematics. A sample of 337 randomly selected SS II…

Enhancing Students' Attitude towards Nigerian Senior Secondary School Physics through the Use of Cooperative, Competitive and Individualistic Learning Strategies

ERIC Educational Resources Information Center

Akinbobola, Akinyemi Olufunminiyi

2009-01-01

The study was conducted to find out the attitude of students towards the use of cooperative, competitive and individualistic learning strategies in Nigerian senior secondary school physics. The design selected for this study was quasi-experimental. A total of 140 students took part in the study and they were selected by a random sampling…

Record statistics of financial time series and geometric random walks

NASA Astrophysics Data System (ADS)

Sabir, Behlool; Santhanam, M. S.

2014-09-01

The study of record statistics of correlated series in physics, such as random walks, is gaining momentum, and several analytical results have been obtained in the past few years. In this work, we study the record statistics of correlated empirical data for which random walk models have relevance. We obtain results for the records statistics of select stock market data and the geometric random walk, primarily through simulations. We show that the distribution of the age of records is a power law with the exponent α lying in the range 1.5≤α≤1.8. Further, the longest record ages follow the Fréchet distribution of extreme value theory. The records statistics of geometric random walk series is in good agreement with that obtained from empirical stock data.

SNP selection and classification of genome-wide SNP data using stratified sampling random forests.

PubMed

Wu, Qingyao; Ye, Yunming; Liu, Yang; Ng, Michael K

2012-09-01

For high dimensional genome-wide association (GWA) case-control data of complex disease, there are usually a large portion of single-nucleotide polymorphisms (SNPs) that are irrelevant with the disease. A simple random sampling method in random forest using default mtry parameter to choose feature subspace, will select too many subspaces without informative SNPs. Exhaustive searching an optimal mtry is often required in order to include useful and relevant SNPs and get rid of vast of non-informative SNPs. However, it is too time-consuming and not favorable in GWA for high-dimensional data. The main aim of this paper is to propose a stratified sampling method for feature subspace selection to generate decision trees in a random forest for GWA high-dimensional data. Our idea is to design an equal-width discretization scheme for informativeness to divide SNPs into multiple groups. In feature subspace selection, we randomly select the same number of SNPs from each group and combine them to form a subspace to generate a decision tree. The advantage of this stratified sampling procedure can make sure each subspace contains enough useful SNPs, but can avoid a very high computational cost of exhaustive search of an optimal mtry, and maintain the randomness of a random forest. We employ two genome-wide SNP data sets (Parkinson case-control data comprised of 408 803 SNPs and Alzheimer case-control data comprised of 380 157 SNPs) to demonstrate that the proposed stratified sampling method is effective, and it can generate better random forest with higher accuracy and lower error bound than those by Breiman's random forest generation method. For Parkinson data, we also show some interesting genes identified by the method, which may be associated with neurological disorders for further biological investigations.

Selective vs routine midline episiotomy for the prevention of third- or fourth-degree lacerations in nulliparous women.

PubMed

Rodriguez, Alexander; Arenas, Edgar A; Osorio, Alba L; Mendez, Omar; Zuleta, John J

2008-03-01

The purpose of this study was to determine whether selective midline episiotomy contributes to the prevention of third- or fourth-degree perineal lacerations. A randomized controlled clinical trial was performed with 446 nulliparous women with deliveries after 28 weeks of pregnancy. Patients were randomized to undergo either routine episiotomy or selective episiotomy. In the selective episiotomy group, episiotomies were performed only in cases of imminent lacerations, fetal distress, or forceps delivery. In the group of 223 patients who underwent routine episiotomy, 32 (14.3%) had third- or fourth-degree perineal lacerations, as compared to 15 (6.8%) in the group of 222 patients undergoing selective episiotomy (relative risk, 2.12; 95% confidence interval, 1.18-3.81). Only reduction in third-degree lacerations was significant when analyzed separately. Moreover, periurethral, labia minora, and superficial vaginal lacerations were significantly more frequent in the selective episiotomy group. The policy of performing selective midline episiotomy in nulliparous patients results in a reduction in the risk of third-degree perineal lacerations.

Fluoxetine, Smoking, and History of Major Depression: A Randomized Controlled Trial

ERIC Educational Resources Information Center

Spring, Bonnie; Doran, Neal; Pagoto, Sherry; McChargue, Dennis; Cook, Jessica Werth; Bailey, Katherine; Crayton, John; Hedeker, Donald

2007-01-01

The study was a randomized placebo-controlled trial testing whether fluoxetine selectively enhances cessation for smokers with a history of depression. Euthymic smokers with (H+, n = 109) or without (H-, n = 138) a history of major depression received 60 mg fluoxetine or placebo plus group behavioral quit-smoking treatment for 12 weeks. Fluoxetine…

A Qualitative Examination of Yoga for Middle School Adolescents

ERIC Educational Resources Information Center

Butzer, Bethany; LoRusso, Amanda Marie; Windsor, Regina; Riley, Frankye; Frame, Kate; Khalsa, Sat Bir S.; Conboy, Lisa

2017-01-01

The present study was part of a group randomized controlled trial in which 7th grade students were assigned to a yoga intervention or physical-education-as-usual. Sixteen students were randomly selected from the yoga condition to participate in one-on-one interviews. Qualitative analyses revealed 13 themes that were organized into two categories:…

Day Hospital and Residential Addiction Treatment: Randomized and Nonrandomized Managed Care Clients

ERIC Educational Resources Information Center

Witbrodt, Jane; Bond, Jason; Kaskutas, Lee Ann; Weisner, Constance; Jaeger, Gary; Pating, David; Moore, Charles

2007-01-01

Male and female managed care clients randomized to day hospital (n=154) or community residential treatment (n=139) were compared on substance use outcomes at 6 and 12 months. To address possible bias in naturalistic studies, outcomes were also examined for clients who self-selected day hospital (n=321) and for clients excluded from randomization…

Georgia's Pre-K Professional Development Evaluation: Technical Appendix. Publication #2015-02B

ERIC Educational Resources Information Center

Early, Diane M.; Pan, Yi; Maxwell, Kelly L.

2014-01-01

The primary purpose of the accompanying final study was to evaluate the impact of two professional development models on teacher-child interactions in Georgia's Pre-K classrooms. Teachers were randomly selected to participate and were randomly assigned to one of the professional development conditions or to a control group. Because of this…

The Effect of Departmentalization on the Reading Achievement of Sixth-Grade Students.

ERIC Educational Resources Information Center

Harris, Mary B.

A study examined whether departmentalization affected the reading achievement of sixth-grade students attending a Chicago public school. A random sample of 30 students was chosen from a group of 53 who received instruction in a departmentalized program. A second random sample of 30 was selected from a total of 54 students who received instruction…

Differences in Mathematics Teachers' Perceived Preparedness to Demonstrate Competence in Secondary School Mathematics Content by Teacher Characteristics

ERIC Educational Resources Information Center

Ng'eno, J. K.; Chesimet, M. C.

2016-01-01

A sample of 300 mathematics teachers drawn from a population of 1500 participated in this study. The participants were selected using systematic random sampling and stratified random sampling (stratified by qualification and gender). The data was collected using self-report questionnaires for mathematics teachers. One tool was used to collect…

Education for Parenthood: Eighth Graders Change Child Rearing Attitudes.

ERIC Educational Resources Information Center

Richett, Diana; Towns, Kathryn

This study examined the effects of an Education for Parenthood Program (EPP) on the childrearing attitudes of eighth grade students. Two eighth grade classes were randomly selected from five sections at a middle school in south central Pennsylvania. One of the classes (both of which were approximatley 60% male and 70% black) was randomly assigned…

Reform-Based-Instructional Method and Learning Styles on Students' Achievement and Retention in Mathematics: Administrative Implications

ERIC Educational Resources Information Center

Modebelu, M. N.; Ogbonna, C. C.

2014-01-01

This study aimed at determining the effect of reform-based-instructional method learning styles on students' achievement and retention in mathematics. A sample size of 119 students was randomly selected. The quasiexperimental design comprising pre-test, post-test, and randomized control group were employed. The Collin Rose learning styles…

Modeling the Stress Complexities of Teaching and Learning of School Physics in Nigeria

ERIC Educational Resources Information Center

Emetere, Moses E.

2014-01-01

This study was designed to investigate the validity of the stress complexity model (SCM) to teaching and learning of school physics in Abuja municipal area council of Abuja, North. About two hundred students were randomly selected by a simple random sampling technique from some schools within the Abuja municipal area council. A survey research…

The Effect of Different Modes of English Captioning on EFL Learners' General Listening Comprehension: Full Text vs. Keyword Captions

ERIC Educational Resources Information Center

Behroozizad, Sorayya; Majidi, Sudabeh

2015-01-01

This study investigated the effect of different modes of English captioning on EFL learners' general listening comprehension. To this end, forty-five intermediate-level learners were selected based on their scores on a standardized English proficiency test (PET) to carry out the study. Then, the selected participants were randomly assigned into…

How to Improve the Peer Review Method: Free-Selection vs Assigned-Pair Protocol Evaluated in a Computer Networking Course

ERIC Educational Resources Information Center

Papadopoulos, Pantelis M.; Lagkas, Thomas D.; Demetriadis, Stavros N.

2012-01-01

This study provides field research evidence on the efficiency of a "free-selection" peer review assignment protocol as compared to the typically implemented "assigned-pair" protocol. The study employed 54 sophomore students who were randomly assigned into three groups: Assigned-Pair (AP) (the teacher assigns student works for review to student…

How Much Videos Win over Audios in Listening Instruction for EFL Learners

ERIC Educational Resources Information Center

Yasin, Burhanuddin; Mustafa, Faisal; Permatasari, Rizki

2017-01-01

This study aims at comparing the benefits of using videos instead of audios for improving students' listening skills. This experimental study used a pre-test and post-test control group design. The sample, selected by cluster random sampling resulted in the selection of 32 second year high school students for each group. The instruments used were…

The Private School Market in Kuwait: A Field Study on Educational Investment Behavior of Kuwaiti Families

ERIC Educational Resources Information Center

Alqahtani, Abdulmuhsen Ayedh

2014-01-01

The current study aims at exploring Kuwaiti families' educational investment behavior pursuant to the selection of a specific private school for their children from the private school market. Using the quantitative approach and the principles of marketing research, a survey was administered to a randomly selected sample of Kuwaiti families (n =…

An Experimental Study of the Effects of Employer-Sponsored Child Care Services on Selected Employee Behaviors. Executive Summary.

ERIC Educational Resources Information Center

Dawson, Ann Gilman; And Others

This executive summary describes a study conducted to determine whether different kinds of employer-supported child care services had differing effects on service users. Turnover and attendance data on 891 randomly selected female employees were gathered from 39 companies and hospitals offering on-site or off-site child care, information and…

An Analysis of Factors Contributing to Achievement in Physics of Secondary Students in Mississippi Schools.

ERIC Educational Resources Information Center

Harpole, Sandra H.; And Others

Designed to examine the factors that contribute to student achievement, this study focused specifically on the relationship between physics achievement and selected teacher characteristics, student characteristics, and school and district characteristics. Questionnaires and attitude surveys were completed by 39 randomly selected Mississippi…

Research Productivity and Its Policy Implications in Higher Education Institutions

ERIC Educational Resources Information Center

Quimbo, Maria Ana T.; Sulabo, Evangeline C.

2014-01-01

Responding to the Commission on Higher Education's development plan of enhancing research culture among higher education institutions, this study was conducted to analyze the research productivity of selected higher education institutions. It covered five state universities in the Philippines where a total of 377 randomly selected faculty members…

Empirically Driven Variable Selection for the Estimation of Causal Effects with Observational Data

ERIC Educational Resources Information Center

Keller, Bryan; Chen, Jianshen

2016-01-01

Observational studies are common in educational research, where subjects self-select or are otherwise non-randomly assigned to different interventions (e.g., educational programs, grade retention, special education). Unbiased estimation of a causal effect with observational data depends crucially on the assumption of ignorability, which specifies…

Scenic Beauty in Summer the Year Before, the Year After, and 4 Years After Harvest

Treesearch

Victor A. Rudis; Hochan Jang; James H. Gramann

2004-01-01

Abstract - This study examined the effects of four silvicultural options (clearcut, group selection, shelterwood, and untreated) on the perceived scenic beauty of shortleaf pine-oak (Pinus echinata-Quercus spp.) stands of national forest land in the Ouachita Mountains of Arkansas. Twelve randomly selected stands...

Mapping of medical acronyms and initialisms to Medical Subject Headings (MeSH) across selected systems

PubMed Central

Shultz, Mary

2006-01-01

Introduction: Given the common use of acronyms and initialisms in the health sciences, searchers may be entering these abbreviated terms rather than full phrases when searching online systems. The purpose of this study is to evaluate how various MEDLINE Medical Subject Headings (MeSH) interfaces map acronyms and initialisms to the MeSH vocabulary. Methods: The interfaces used in this study were: the PubMed MeSH database, the PubMed Automatic Term Mapping feature, the NLM Gateway Term Finder, and Ovid MEDLINE. Acronyms and initialisms were randomly selected from 2 print sources. The test data set included 415 randomly selected acronyms and initialisms whose related meanings were found to be MeSH terms. Each acronym and initialism was entered into each MEDLINE MeSH interface to determine if it mapped to the corresponding MeSH term. Separately, 46 commonly used acronyms and initialisms were tested. Results: While performance differed widely, the success rates were low across all interfaces for the randomly selected terms. The common acronyms and initialisms tested at higher success rates across the interfaces, but the differences between the interfaces remained. Conclusion: Online interfaces do not always map medical acronyms and initialisms to their corresponding MeSH phrases. This may lead to inaccurate results and missed information if acronyms and initialisms are used in search strategies. PMID:17082832

The Effect of Basis Selection on Static and Random Acoustic Response Prediction Using a Nonlinear Modal Simulation

NASA Technical Reports Server (NTRS)

Rizzi, Stephen A.; Przekop, Adam

2005-01-01

An investigation of the effect of basis selection on geometric nonlinear response prediction using a reduced-order nonlinear modal simulation is presented. The accuracy is dictated by the selection of the basis used to determine the nonlinear modal stiffness. This study considers a suite of available bases including bending modes only, bending and membrane modes, coupled bending and companion modes, and uncoupled bending and companion modes. The nonlinear modal simulation presented is broadly applicable and is demonstrated for nonlinear quasi-static and random acoustic response of flat beam and plate structures with isotropic material properties. Reduced-order analysis predictions are compared with those made using a numerical simulation in physical degrees-of-freedom to quantify the error associated with the selected modal bases. Bending and membrane responses are separately presented to help differentiate the bases.

Selective pinning control of the average disease transmissibility in an HIV contact network

NASA Astrophysics Data System (ADS)

du Toit, E. F.; Craig, I. K.

2015-07-01

Medication is applied to the HIV-infected nodes of high-risk contact networks with the aim of controlling the spread of disease to a predetermined maximum level. This intervention, known as pinning control, is performed both selectively and randomly in the network. These strategies are applied to 300 independent realizations per reference level of incidence on connected undirectional networks without isolated components and varying in size from 100 to 10 000 nodes per network. It is shown that a selective on-off pinning control strategy can control the networks studied with limited steady-state error and, comparing the medians of the doses from both strategies, uses 51.3% less medication than random pinning of all infected nodes. Selective pinning could possibly be used by public health specialists to identify the maximum level of HIV incidence in a population that can be achieved in a constrained funding environment.

The Coalescent Process in Models with Selection

PubMed Central

Kaplan, N. L.; Darden, T.; Hudson, R. R.

1988-01-01

Statistical properties of the process describing the genealogical history of a random sample of genes are obtained for a class of population genetics models with selection. For models with selection, in contrast to models without selection, the distribution of this process, the coalescent process, depends on the distribution of the frequencies of alleles in the ancestral generations. If the ancestral frequency process can be approximated by a diffusion, then the mean and the variance of the number of segregating sites due to selectively neutral mutations in random samples can be numerically calculated. The calculations are greatly simplified if the frequencies of the alleles are tightly regulated. If the mutation rates between alleles maintained by balancing selection are low, then the number of selectively neutral segregating sites in a random sample of genes is expected to substantially exceed the number predicted under a neutral model. PMID:3066685

Measuring socioeconomic status in multicountry studies: results from the eight-country MAL-ED study

PubMed Central

2014-01-01

Background There is no standardized approach to comparing socioeconomic status (SES) across multiple sites in epidemiological studies. This is particularly problematic when cross-country comparisons are of interest. We sought to develop a simple measure of SES that would perform well across diverse, resource-limited settings. Methods A cross-sectional study was conducted with 800 children aged 24 to 60 months across eight resource-limited settings. Parents were asked to respond to a household SES questionnaire, and the height of each child was measured. A statistical analysis was done in two phases. First, the best approach for selecting and weighting household assets as a proxy for wealth was identified. We compared four approaches to measuring wealth: maternal education, principal components analysis, Multidimensional Poverty Index, and a novel variable selection approach based on the use of random forests. Second, the selected wealth measure was combined with other relevant variables to form a more complete measure of household SES. We used child height-for-age Z-score (HAZ) as the outcome of interest. Results Mean age of study children was 41 months, 52% were boys, and 42% were stunted. Using cross-validation, we found that random forests yielded the lowest prediction error when selecting assets as a measure of household wealth. The final SES index included access to improved water and sanitation, eight selected assets, maternal education, and household income (the WAMI index). A 25% difference in the WAMI index was positively associated with a difference of 0.38 standard deviations in HAZ (95% CI 0.22 to 0.55). Conclusions Statistical learning methods such as random forests provide an alternative to principal components analysis in the development of SES scores. Results from this multicountry study demonstrate the validity of a simplified SES index. With further validation, this simplified index may provide a standard approach for SES adjustment across resource-limited settings. PMID:24656134

Model Selection with the Linear Mixed Model for Longitudinal Data

ERIC Educational Resources Information Center

Ryoo, Ji Hoon

2011-01-01

Model building or model selection with linear mixed models (LMMs) is complicated by the presence of both fixed effects and random effects. The fixed effects structure and random effects structure are codependent, so selection of one influences the other. Most presentations of LMM in psychology and education are based on a multilevel or…

Random one-of-N selector

DOEpatents

Kronberg, J.W.

1993-04-20

An apparatus for selecting at random one item of N items on the average comprising counter and reset elements for counting repeatedly between zero and N, a number selected by the user, a circuit for activating and deactivating the counter, a comparator to determine if the counter stopped at a count of zero, an output to indicate an item has been selected when the count is zero or not selected if the count is not zero. Randomness is provided by having the counter cycle very often while varying the relatively longer duration between activation and deactivation of the count. The passive circuit components of the activating/deactivating circuit and those of the counter are selected for the sensitivity of their response to variations in temperature and other physical characteristics of the environment so that the response time of the circuitry varies. Additionally, the items themselves, which may be people, may vary in shape or the time they press a pushbutton, so that, for example, an ultrasonic beam broken by the item or person passing through it will add to the duration of the count and thus to the randomness of the selection.

Random one-of-N selector

DOEpatents

Kronberg, James W.

1993-01-01

An apparatus for selecting at random one item of N items on the average comprising counter and reset elements for counting repeatedly between zero and N, a number selected by the user, a circuit for activating and deactivating the counter, a comparator to determine if the counter stopped at a count of zero, an output to indicate an item has been selected when the count is zero or not selected if the count is not zero. Randomness is provided by having the counter cycle very often while varying the relatively longer duration between activation and deactivation of the count. The passive circuit components of the activating/deactivating circuit and those of the counter are selected for the sensitivity of their response to variations in temperature and other physical characteristics of the environment so that the response time of the circuitry varies. Additionally, the items themselves, which may be people, may vary in shape or the time they press a pushbutton, so that, for example, an ultrasonic beam broken by the item or person passing through it will add to the duration of the count and thus to the randomness of the selection.

Population differentiation in Pacific salmon: local adaptation, genetic drift, or the environment?

USGS Publications Warehouse

Adkison, Milo D.

1995-01-01

Morphological, behavioral, and life-history differences between Pacific salmon (Oncorhynchus spp.) populations are commonly thought to reflect local adaptation, and it is likewise common to assume that salmon populations separated by small distances are locally adapted. Two alternatives to local adaptation exist: random genetic differentiation owing to genetic drift and founder events, and genetic homogeneity among populations, in which differences reflect differential trait expression in differing environments. Population genetics theory and simulations suggest that both alternatives are possible. With selectively neutral alleles, genetic drift can result in random differentiation despite many strays per generation. Even weak selection can prevent genetic drift in stable populations; however, founder effects can result in random differentiation despite selective pressures. Overlapping generations reduce the potential for random differentiation. Genetic homogeneity can occur despite differences in selective regimes when straying rates are high. In sum, localized differences in selection should not always result in local adaptation. Local adaptation is favored when population sizes are large and stable, selection is consistent over large areas, selective diffeentials are large, and straying rates are neither too high nor too low. Consideration of alternatives to local adaptation would improve both biological research and salmon conservation efforts.

Factors influencing the recruitment and retention of literacy learners in Oman

NASA Astrophysics Data System (ADS)

Al-Barwani, Thuwayba; Kelly, Edward F.

1985-12-01

The study investigates factors influencing the recruitment and retention of learners in the national adult literacy programme in Oman. Personal interviews were conducted in the interior and Capital regions of Oman (N=102). Respondents included 46 randomly selected enrolled learners, 26 randomly selected dropouts and 30 unenrolled adults. Results of the interviews were content-analyzed and frequencies, cross tabulations and Chi-square were calculated. Findings indicated regional differences in the adults' motivation for enrolling, but the spiritual motive was over all the most significant. Men and women reported different patterns of conflict and obstacles in completing their literacy studies: Men indicated work demands as their biggest obstacle while women complained about family responsibilities. Programme attrition was mainly attributed to structural characteristics of the programme.

Analysis of the relationship between the number of citations and the quality evaluated by experts in psychology journals.

PubMed

Buela-Casal, Gualberto; Zych, Izabela

2010-05-01

The study analyzes the relationship between the number of citations as calculated by the IN-RECS database and the quality evaluated by experts. The articles published in journals of the Spanish Psychological Association between 1996 and 2008 and selected by the Editorial Board of Psychology in Spain were the subject of the study. Psychology in Spain is a journal that includes the best papers published throughout the previous year, chosen by the Editorial Board made up of fifty specialists of acknowledged prestige within Spanish psychology and translated into English. The number of the citations of the 140 original articles republished in Psychology in Spain was compared to the number of the citations of the 140 randomly selected articles. Additionally, the study searched for a relationship between the number of the articles selected from each journal and their mean number of citations. The number of citations received by the best articles as evaluated by experts is significantly higher than the number of citations of the randomly selected articles. Also, the number of citations is higher in the articles from the most frequently selected journals. A statistically significant relation between the quality evaluated by experts and the number of the citations was found.

Evaluation of Model Specification, Variable Selection, and Adjustment Methods in Relation to Propensity Scores and Prognostic Scores in Multilevel Data

ERIC Educational Resources Information Center

Yu, Bing; Hong, Guanglei

2012-01-01

This study uses simulation examples representing three types of treatment assignment mechanisms in data generation (the random intercept and slopes setting, the random intercept setting, and a third setting with a cluster-level treatment and an individual-level outcome) in order to determine optimal procedures for reducing bias and improving…

The Effect of Herrmann Whole Brain Teaching Method on Students' Understanding of Simple Electric Circuits

ERIC Educational Resources Information Center

Bawaneh, Ali Khalid Ali; Nurulazam Md Zain, Ahmad; Salmiza, Saleh

2011-01-01

The purpose of this study was to investigate the effect of Herrmann Whole Brain Teaching Method over conventional teaching method on eight graders in their understanding of simple electric circuits in Jordan. Participants (N = 273 students; M = 139, F = 134) were randomly selected from Bani Kenanah region-North of Jordan and randomly assigned to…

Midwives Performance in Early Detection of Growth and Development Irregularities of Children Based on Task Commitment

ERIC Educational Resources Information Center

Utami, Sri; Nursalam; Hargono, Rachmat; Susilaningrum, Rekawati

2016-01-01

The purpose of this study was to analyze the performance of midwives based on the task commitment. This was an observational analytic with cross sectional approach. Multistage random sampling was used to determine the public health center, proportional random sampling to selected participants. The samples were 222 midwives in the public health…

Teachers' Methodologies and Sources of Information on HIV/AIDS for Students with Visual Impairments in Selected Residential and Integrated Schools in Ghana

ERIC Educational Resources Information Center

Hayford, Samuel K.; Ocansey, Frederick

2017-01-01

This study reports part of a national survey on sources of information, education and communication materials on HIV/AIDS available to students with visual impairments in residential, segregated, and integrated schools in Ghana. A multi-staged stratified random sampling procedure and a purposive and simple random sampling approach, where…

Modeling of Academic Achievement of Primary School Students in Ethiopia Using Bayesian Multilevel Approach

ERIC Educational Resources Information Center

Sebro, Negusse Yohannes; Goshu, Ayele Taye

2017-01-01

This study aims to explore Bayesian multilevel modeling to investigate variations of average academic achievement of grade eight school students. A sample of 636 students is randomly selected from 26 private and government schools by a two-stage stratified sampling design. Bayesian method is used to estimate the fixed and random effects. Input and…

Alcohol- and Drug-Involved Driving in the United States: Methodology for the 2007 National Roadside Survey

ERIC Educational Resources Information Center

Lacey, John H.; Kelley-Baker, Tara; Voas, Robert B.; Romano, Eduardo; Furr-Holden, C. Debra; Torres, Pedro; Berning, Amy

2011-01-01

This article describes the methodology used in the 2007 U.S. National Roadside Survey to estimate the prevalence of alcohol- and drug-impaired driving and alcohol- and drug-involved driving. This study involved randomly stopping drivers at 300 locations across the 48 continental U.S. states at sites selected through a stratified random sampling…

Detection of Cytomegalovirus (CMV) Infection in Wheezing Infants by Urine DNA and Serum IgG Testing.

PubMed

Zeng, Zhao-Cheng; Chang, Qing; Sun, Zhi-Wei; Song, Ming-Mei; Jin, Xin-Ling; Jiang, Shu-Ya; Yang, Xia

2017-03-11

BACKGROUND The aim of this study was to investigate the involvement of CMV infection in wheezing infants and the association between CMV-DNA and immunoglobulins (Igs). MATERIAL AND METHODS A total of 243 wheezing infants and 3,000 parturients were enrolled in this study. The infants were randomly grouped to receive blood HCMV-DNA tests (n=46) or urine HCMV-DNA tests (n=197). Furthermore, all participants had serum CMV-specific IgM and IgG testing. Afterwards, 10 HCMV-IgG positive infants were randomly selected for simultaneous blood and urine HCMV-DNA tests, and 25 HCMV-IgG positive puerperants were randomly selected for urine HCMV-DNA tests. RESULTS The detection rate of urine HCMV-DNA was significantly higher than that of blood HCMV-DNA (67.5% vs. 13.0%, p<0.001). Fifteen (6.2%) and 190 (80.0%) infants showed positive CMV-specific IgM and IgG results (p<0.001), respectively. Among the 10 HCMV-IgG positive infants tested further, only two infants had positive HCMV-DNA blood tests, while all of the 10 infants had positive HCMV-DNA urine tests. However, HCMV-DNA was not detected in the urine of the 25 randomly selected parturients positive for HCMV-IgG. CONCLUSIONS CMV infection may be one of the causes of wheezing in infants; CMV infection can be detected by urine-HCMV-DNA and serum HCMV-IgG testing. Infants were more susceptible to CMV infection than parturients.

A Time-Series Water Level Forecasting Model Based on Imputation and Variable Selection Method.

PubMed

Yang, Jun-He; Cheng, Ching-Hsue; Chan, Chia-Pan

2017-01-01

Reservoirs are important for households and impact the national economy. This paper proposed a time-series forecasting model based on estimating a missing value followed by variable selection to forecast the reservoir's water level. This study collected data from the Taiwan Shimen Reservoir as well as daily atmospheric data from 2008 to 2015. The two datasets are concatenated into an integrated dataset based on ordering of the data as a research dataset. The proposed time-series forecasting model summarily has three foci. First, this study uses five imputation methods to directly delete the missing value. Second, we identified the key variable via factor analysis and then deleted the unimportant variables sequentially via the variable selection method. Finally, the proposed model uses a Random Forest to build the forecasting model of the reservoir's water level. This was done to compare with the listing method under the forecasting error. These experimental results indicate that the Random Forest forecasting model when applied to variable selection with full variables has better forecasting performance than the listing model. In addition, this experiment shows that the proposed variable selection can help determine five forecast methods used here to improve the forecasting capability.

The Causal Effect of Tracing by Peer Health Workers on Return to Clinic Among Patients Who Were Lost to Follow-up From Antiretroviral Therapy in Eastern Africa: A "Natural Experiment" Arising From Surveillance of Lost Patients.

PubMed

Bershetyn, Anna; Odeny, Thomas A; Lyamuya, Rita; Nakiwogga-Muwanga, Alice; Diero, Lameck; Bwana, Mwebesa; Braitstein, Paula; Somi, Geoffrey; Kambugu, Andrew; Bukusi, Elizabeth; Hartogensis, Wendy; Glidden, David V; Wools-Kaloustian, Kara; Yiannoutsos, Constantin; Martin, Jeffrey; Geng, Elvin H

2017-06-01

The effect of tracing human immunodeficiency virus (HIV)-infected patients who are lost to follow-up (LTFU) on reengagement has not been rigorously assessed. We carried out an ex post analysis of a surveillance study in which LTFU patients were randomly selected for tracing to identify the effect of tracing on reengagement. We evaluated HIV-infected adults on antiretroviral therapy who were LTFU (>90 days late for last visit) at 14 clinics in Uganda, Kenya, and Tanzania. A random sample of LTFU patients was selected for tracing by peer health workers. We assessed the effect of selection for tracing using Kaplan-Meier estimates of reengagement among all patients as well as the subset of LTFU patients who were alive, contacted in person by the tracer, and out of care. Of 5781 eligible patients, 991 (17%) were randomly selected for tracing. One year after selection for tracing, 13.3% (95% confidence interval [CI], 11.1%-15.3%) of those selected for tracing returned compared with 10.0% (95% CI, 9.1%-10.8%) of those not randomly selected, an adjusted risk difference of 3.0% (95% CI, .7%-5.3%). Among patients found to be alive, personally contacted, and out of care, tracing increased the absolute probability of return at 1 year by 22% (95% CI, 7.1%-36.2%). The effect of tracing on rate of return to clinic decayed with a half-life of 7.0 days after tracing (95% CI, 2.6 %-12.9%). Tracing interventions increase reengagement, but developing methods for targeting LTFU patients most likely to benefit can make this practice more efficient. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Random forests ensemble classifier trained with data resampling strategy to improve cardiac arrhythmia diagnosis.

PubMed

Ozçift, Akin

2011-05-01

Supervised classification algorithms are commonly used in the designing of computer-aided diagnosis systems. In this study, we present a resampling strategy based Random Forests (RF) ensemble classifier to improve diagnosis of cardiac arrhythmia. Random forests is an ensemble classifier that consists of many decision trees and outputs the class that is the mode of the class's output by individual trees. In this way, an RF ensemble classifier performs better than a single tree from classification performance point of view. In general, multiclass datasets having unbalanced distribution of sample sizes are difficult to analyze in terms of class discrimination. Cardiac arrhythmia is such a dataset that has multiple classes with small sample sizes and it is therefore adequate to test our resampling based training strategy. The dataset contains 452 samples in fourteen types of arrhythmias and eleven of these classes have sample sizes less than 15. Our diagnosis strategy consists of two parts: (i) a correlation based feature selection algorithm is used to select relevant features from cardiac arrhythmia dataset. (ii) RF machine learning algorithm is used to evaluate the performance of selected features with and without simple random sampling to evaluate the efficiency of proposed training strategy. The resultant accuracy of the classifier is found to be 90.0% and this is a quite high diagnosis performance for cardiac arrhythmia. Furthermore, three case studies, i.e., thyroid, cardiotocography and audiology, are used to benchmark the effectiveness of the proposed method. The results of experiments demonstrated the efficiency of random sampling strategy in training RF ensemble classification algorithm. Copyright © 2011 Elsevier Ltd. All rights reserved.

Impact of Substance Abuse on Academic Performance among Adolescent Students of Colleges of Education in Kwara State, Nigeria

ERIC Educational Resources Information Center

Akanbi, Muritala Ishola; Augustina, Godwin; Theophilus, Anyio Bahago; Muritala, Muhammad; Ajiboye, Ajiboye Stephen

2015-01-01

The study investigated the impact of substance abuse on adolescent on academic performance in colleges of education in Kwara State. The design used for the study was the survey. A sample of 150 adolescent students was randomly selected form selected departments in three colleges of education in the State. A validated instrument, Drug Habit…

An Experimental Study of the Effects of Employer-Sponsored Child Care Services on Selected Employee Behaviors.

ERIC Educational Resources Information Center

Dawson, Ann Gilman; And Others

Described in this report is a study conducted to determine whether different kinds of employer-supported child care services had differing effects on the users of these services. Data were gathered on a year's attendance and turnover rates for 891 female employees who had used employer-provided child care. Subjects were randomly selected from 39…

Exercise as Treatment for Anxiety: Systematic Review and Analysis

PubMed Central

Stonerock, Gregory L.; Hoffman, Benson M.; Smith, Patrick J.; Blumenthal, James A.

2015-01-01

Background Exercise has been shown to reduce symptoms of anxiety, but few studies have studied exercise in individuals pre-selected because of their high anxiety. Purpose To review and critically evaluate studies of exercise training in adults with either high levels of anxiety or an anxiety disorder. Methods We conducted a systematic review of randomized clinical trials (RCTs) in which anxious adults were randomized to an exercise or non-exercise control condition. Data were extracted concerning anxiety outcomes and study design. Existing meta-analyses were also reviewed. Results Evidence from 12 RCTs suggested benefits of exercise, for select groups, similar to established treatments and greater than placebo. However, most studies had significant methodological limitations, including small sample sizes, concurrent therapies, and inadequate assessment of adherence and fitness levels. Conclusions Exercise may be a useful treatment for anxiety, but lack of data from rigorous, methodologically sound RCTs precludes any definitive conclusions about its effectiveness. PMID:25697132

Do Evidence-Based Youth Psychotherapies Outperform Usual Clinical Care? A Multilevel Meta-Analysis

PubMed Central

Weisz, John R.; Kuppens, Sofie; Eckshtain, Dikla; Ugueto, Ana M.; Hawley, Kristin M.; Jensen-Doss, Amanda

2013-01-01

Context Research across four decades has produced numerous empirically-tested evidence-based psychotherapies (EBPs) for youth psychopathology, developed to improve upon usual clinical interventions. Advocates argue that these should replace usual care; but do the EBPs produce better outcomes than usual care? Objective This question was addressed in a meta-analysis of 52 randomized trials directly comparing EBPs to usual care. Analyses assessed the overall effect of EBPs vs. usual care, and candidate moderators; multilevel analysis was used to address the dependency among effect sizes that is common but typically unaddressed in psychotherapy syntheses. Data Sources The PubMed, PsychINFO, and Dissertation Abstracts International databases were searched for studies from January 1, 1960 – December 31, 2010. Study Selection 507 randomized youth psychotherapy trials were identified. Of these, the 52 studies that compared EBPs to usual care were included in the meta-analysis. Data Extraction Sixteen variables (participant, treatment, and study characteristics) were extracted from each study, and effect sizes were calculated for all EBP versus usual care comparisons. Data Synthesis EBPs outperformed usual care. Mean effect size was 0.29; the probability was 58% that a randomly selected youth receiving an EBP would be better off after treatment than a randomly selected youth receiving usual care. Three variables moderated treatment benefit: Effect sizes decreased for studies conducted outside North America, for studies in which all participants were impaired enough to qualify for diagnoses, and for outcomes reported by people other than the youths and parents in therapy. For certain key groups (e.g., studies using clinically referred samples and diagnosed samples), significant EBP effects were not demonstrated. Conclusions EBPs outperformed usual care, but the EBP advantage was modest and moderated by youth, location, and assessment characteristics. There is room for improvement in EBPs, both in the magnitude and range of their benefit, relative to usual care. PMID:23754332

Music in the cath lab: who should select it?

PubMed

Goertz, Wolfram; Dominick, Klaus; Heussen, Nicole; vom Dahl, Juergen

2011-05-01

The ALMUT study wants to evaluate the anxiolytic effects of different music styles and no music in 200 patients undergoing cardiac catheterization and to assess if there is a difference if patients select one of these therapies or are randomized to one of them. The anxiolytic and analgesic effects of music have been described in previous trials. Some authors have suggested to evaluate whether patient-selected music is more effective than the music selected by the physician in reducing anxiety and stress levels. After randomization 100 patients (group A) were allowed to choose between classical music, relaxing modern music, smooth jazz, and no music. One hundred patients (group B) were randomized directly to one of these therapies (n = 25 each). Complete data were available for 197 patients (65 ± 10 years; 134 male). Using the State-Trait Anxiety Inventory (STAI) all patients in group B who listened to music showed a significantly higher decrease of their anxiety level (STAI-State difference pre-post of 16.8 ± 10.2) compared to group A (13.3 ± 11.1; p = 0.0176). Patients without music (6.2 ± 6.7) had a significantly weaker reduction of anxiety compared to all music-listeners (14.9 ± 10.7, p < 0.0001). The positive effects of music in the cath lab support previous reports. Surprisingly, the hypothesis that the patient's choice of preferred music might yield higher benefits than a randomized assignment could be dismissed.

An Investigation of Plans and Procedures for Increasing Student Enrollments in Selected Southern California Community Colleges.

ERIC Educational Resources Information Center

Huguley, Sally M.

A study involving interviews with administrators at seven randomly selected Southern California community colleges was conducted to identify the marketing strategies undertaken by these institutions to increase student recruitment. During the interviews, respondents were asked to: (1) outline the functions of their public relations office; (2)…

Using Fit Indexes to Select a Covariance Model for Longitudinal Data

ERIC Educational Resources Information Center

Liu, Siwei; Rovine, Michael J.; Molenaar, Peter C. M.

2012-01-01

This study investigated the performance of fit indexes in selecting a covariance structure for longitudinal data. Data were simulated to follow a compound symmetry, first-order autoregressive, first-order moving average, or random-coefficients covariance structure. We examined the ability of the likelihood ratio test (LRT), root mean square error…

Educational Research with Real-World Data: Reducing Selection Bias with Propensity Scores

ERIC Educational Resources Information Center

Adelson, Jill L.

2013-01-01

Often it is infeasible or unethical to use random assignment in educational settings to study important constructs and questions. Hence, educational research often uses observational data, such as large-scale secondary data sets and state and school district data, and quasi-experimental designs. One method of reducing selection bias in estimations…

How Special Are Teachers of Specialized Schools? Assessing Self-Confidence Levels in the Technology Domain

ERIC Educational Resources Information Center

Çatma, Zehra; Corlu, Mehmet Sencer

2016-01-01

This study investigates whether specialized high school mathematics teachers, chosen to educate selected students, are mentally ready to integrate Fatih project technologies into their teaching. Forty mathematics teachers from randomly selected specialized and general high schools in Ankara responded to a survey comprising 31 items grouped under…

The Richer, the Happier? An Empirical Investigation in Selected European Countries

ERIC Educational Resources Information Center

Seghieri, Chiara; Desantis, Gustavo; Tanturri, Maria Letizia

2006-01-01

This study analyses the relationship between subjective and objective measures of well-being in selected European countries using the data of the European Community Household Panel (ECHP). In the first part of the paper, we develop a random-effect ordered probit model, separately for each country, relating the subjective measure of income…

Attenders versus Slackers: A Classroom Demonstration of Quasi-Experimentation and Self-Selecting Samples

ERIC Educational Resources Information Center

Stellmack, Mark A.

2013-01-01

Studies of the effects of class attendance on class performance typically are quasi-experimental because students choose whether or not to attend class; that is, the samples are self-selecting. The lack of random assignment prevents one from establishing a causal relationship between attendance and performance. Relating attendance to performance…

Site Selection in Experiments: An Assessment of Site Recruitment and Generalizability in Two Scale-Up Studies

ERIC Educational Resources Information Center

Tipton, Elizabeth; Fellers, Lauren; Caverly, Sarah; Vaden-Kiernan, Michael; Borman, Geoffrey; Sullivan, Kate; Ruiz de Castilla, Veronica

2016-01-01

Recently, statisticians have begun developing methods to improve the generalizability of results from large-scale experiments in education. This work has included the development of methods for improved site selection when random sampling is infeasible, including the use of stratification and targeted recruitment strategies. This article provides…

40 CFR 761.355 - Third level of sample selection.

Code of Federal Regulations, 2012 CFR

2012-07-01

... of sample selection further reduces the size of the subsample to 100 grams which is suitable for the... procedures in § 761.353 of this part into 100 gram portions. (b) Use a random number generator or random number table to select one 100 gram size portion as a sample for a procedure used to simulate leachate...

40 CFR 761.355 - Third level of sample selection.

Code of Federal Regulations, 2011 CFR

2011-07-01

... of sample selection further reduces the size of the subsample to 100 grams which is suitable for the... procedures in § 761.353 of this part into 100 gram portions. (b) Use a random number generator or random number table to select one 100 gram size portion as a sample for a procedure used to simulate leachate...

40 CFR 761.355 - Third level of sample selection.

Code of Federal Regulations, 2013 CFR

2013-07-01

... of sample selection further reduces the size of the subsample to 100 grams which is suitable for the... procedures in § 761.353 of this part into 100 gram portions. (b) Use a random number generator or random number table to select one 100 gram size portion as a sample for a procedure used to simulate leachate...

40 CFR 761.355 - Third level of sample selection.

Code of Federal Regulations, 2010 CFR

2010-07-01

... of sample selection further reduces the size of the subsample to 100 grams which is suitable for the... procedures in § 761.353 of this part into 100 gram portions. (b) Use a random number generator or random number table to select one 100 gram size portion as a sample for a procedure used to simulate leachate...

40 CFR 761.355 - Third level of sample selection.

Code of Federal Regulations, 2014 CFR

2014-07-01

... of sample selection further reduces the size of the subsample to 100 grams which is suitable for the... procedures in § 761.353 of this part into 100 gram portions. (b) Use a random number generator or random number table to select one 100 gram size portion as a sample for a procedure used to simulate leachate...

Relationships Between Habitat and Snag Characteristics and the Reproductive Success of the Brown-headed Nuthatch (Sitta pusilla) in Eastern Texas

Treesearch

L. Lynnette Dornak; D. Brent Burt; Dean W. Coble; Richard N. Conner

2004-01-01

Habitat use and reproductive success of the Brown-headed Nuthatch (Sitta pusilla Latham) were studied in East Texas during the 2001­2002 breed- ing seasons. We compared nest cavity selection at used and randomly selected non-used areas. Height of nest trees, midstory density, and percent leaf litter were negatively correlated with nest site selection...

A Descriptive Analysis of Selected Community Stakeholder Opinions regarding Potentially Critical Factors in School Bond Referenda Success or Failure in Kansas during the Years 2004-2007

ERIC Educational Resources Information Center

Kraus, Brian W.

2009-01-01

The purpose of this study was to analyze opinions of selected school district stakeholders regarding potentially critical factors in school bond referendum success and failure in Kansas during the years 2004-2007. Of the 72 eligible school districts, one district was randomly selected from each of six groups formed through a stratified random…

Applications of step-selection functions in ecology and conservation.

PubMed

Thurfjell, Henrik; Ciuti, Simone; Boyce, Mark S

2014-01-01

Recent progress in positioning technology facilitates the collection of massive amounts of sequential spatial data on animals. This has led to new opportunities and challenges when investigating animal movement behaviour and habitat selection. Tools like Step Selection Functions (SSFs) are relatively new powerful models for studying resource selection by animals moving through the landscape. SSFs compare environmental attributes of observed steps (the linear segment between two consecutive observations of position) with alternative random steps taken from the same starting point. SSFs have been used to study habitat selection, human-wildlife interactions, movement corridors, and dispersal behaviours in animals. SSFs also have the potential to depict resource selection at multiple spatial and temporal scales. There are several aspects of SSFs where consensus has not yet been reached such as how to analyse the data, when to consider habitat covariates along linear paths between observations rather than at their endpoints, how many random steps should be considered to measure availability, and how to account for individual variation. In this review we aim to address all these issues, as well as to highlight weak features of this modelling approach that should be developed by further research. Finally, we suggest that SSFs could be integrated with state-space models to classify behavioural states when estimating SSFs.

Assessment of wadeable stream resources in the driftless area ecoregion in Western Wisconsin using a probabilistic sampling design.

PubMed

Miller, Michael A; Colby, Alison C C; Kanehl, Paul D; Blocksom, Karen

2009-03-01

The Wisconsin Department of Natural Resources (WDNR), with support from the U.S. EPA, conducted an assessment of wadeable streams in the Driftless Area ecoregion in western Wisconsin using a probabilistic sampling design. This ecoregion encompasses 20% of Wisconsin's land area and contains 8,800 miles of perennial streams. Randomly-selected stream sites (n = 60) equally distributed among stream orders 1-4 were sampled. Watershed land use, riparian and in-stream habitat, water chemistry, macroinvertebrate, and fish assemblage data were collected at each true random site and an associated "modified-random" site on each stream that was accessed via a road crossing nearest to the true random site. Targeted least-disturbed reference sites (n = 22) were also sampled to develop reference conditions for various physical, chemical, and biological measures. Cumulative distribution function plots of various measures collected at the true random sites evaluated with reference condition thresholds, indicate that high proportions of the random sites (and by inference the entire Driftless Area wadeable stream population) show some level of degradation. Study results show no statistically significant differences between the true random and modified-random sample sites for any of the nine physical habitat, 11 water chemistry, seven macroinvertebrate, or eight fish metrics analyzed. In Wisconsin's Driftless Area, 79% of wadeable stream lengths were accessible via road crossings. While further evaluation of the statistical rigor of using a modified-random sampling design is warranted, sampling randomly-selected stream sites accessed via the nearest road crossing may provide a more economical way to apply probabilistic sampling in stream monitoring programs.

Peculiarities of the statistics of spectrally selected fluorescence radiation in laser-pumped dye-doped random media

NASA Astrophysics Data System (ADS)

Yuvchenko, S. A.; Ushakova, E. V.; Pavlova, M. V.; Alonova, M. V.; Zimnyakov, D. A.

2018-04-01

We consider the practical realization of a new optical probe method of the random media which is defined as the reference-free path length interferometry with the intensity moments analysis. A peculiarity in the statistics of the spectrally selected fluorescence radiation in laser-pumped dye-doped random medium is discussed. Previously established correlations between the second- and the third-order moments of the intensity fluctuations in the random interference patterns, the coherence function of the probe radiation, and the path difference probability density for the interfering partial waves in the medium are confirmed. The correlations were verified using the statistical analysis of the spectrally selected fluorescence radiation emitted by a laser-pumped dye-doped random medium. Water solution of Rhodamine 6G was applied as the doping fluorescent agent for the ensembles of the densely packed silica grains, which were pumped by the 532 nm radiation of a solid state laser. The spectrum of the mean path length for a random medium was reconstructed.

CURE-SMOTE algorithm and hybrid algorithm for feature selection and parameter optimization based on random forests.

PubMed

Ma, Li; Fan, Suohai

2017-03-14

The random forests algorithm is a type of classifier with prominent universality, a wide application range, and robustness for avoiding overfitting. But there are still some drawbacks to random forests. Therefore, to improve the performance of random forests, this paper seeks to improve imbalanced data processing, feature selection and parameter optimization. We propose the CURE-SMOTE algorithm for the imbalanced data classification problem. Experiments on imbalanced UCI data reveal that the combination of Clustering Using Representatives (CURE) enhances the original synthetic minority oversampling technique (SMOTE) algorithms effectively compared with the classification results on the original data using random sampling, Borderline-SMOTE1, safe-level SMOTE, C-SMOTE, and k-means-SMOTE. Additionally, the hybrid RF (random forests) algorithm has been proposed for feature selection and parameter optimization, which uses the minimum out of bag (OOB) data error as its objective function. Simulation results on binary and higher-dimensional data indicate that the proposed hybrid RF algorithms, hybrid genetic-random forests algorithm, hybrid particle swarm-random forests algorithm and hybrid fish swarm-random forests algorithm can achieve the minimum OOB error and show the best generalization ability. The training set produced from the proposed CURE-SMOTE algorithm is closer to the original data distribution because it contains minimal noise. Thus, better classification results are produced from this feasible and effective algorithm. Moreover, the hybrid algorithm's F-value, G-mean, AUC and OOB scores demonstrate that they surpass the performance of the original RF algorithm. Hence, this hybrid algorithm provides a new way to perform feature selection and parameter optimization.

Silicon solar cell process development, fabrication and analysis

NASA Technical Reports Server (NTRS)

Iles, P. A.; Leung, D. C.

1982-01-01

For UCP Si, randomly selected wafers and wafers cut from two specific ingots were studied. For the randomly selected wafers, a moderate gettering diffusion had little effect. Moreover, an efficiency up to 14% AMI was achieved with advanced processes. For the two specific UCP ingots, ingot #5848-13C displayed severe impurity effects as shown by lower 3sc in the middle of the ingot and low CFF in the top of the ingot. Also the middle portions of this ingot responded to a series of progressively more severe gettering diffusion. Unexplained was the fact that severely gettered samples of this ingot displayed a negative light biased effect on the minority carrier diffusion length while the nongettered or moderately gettered ones had the more conventional positive light biased effect on diffusion length. On the other hand, ingot C-4-21A did not have the problem of ingot 5848-13C and behaved like to the randomly selected wafers. The top half of the ingot was shown to be slightly superior to the bottom half, but moderate gettering helped to narrow the gap.

For whom should we use selective decontamination of the digestive tract?

PubMed

de Smet, Anne Marie G A; Bonten, Marc J M; Kluytmans, Jan A J W

2012-04-01

This review discusses the relevant studies on selective decontamination of the digestive tract (SDD) published between 2009 and mid-2011. In a multicenter cluster-randomized cross-over study in the Netherlands, SDD and selective oropharyngeal decontamination (SOD) were associated with higher survival at day 28, with a lower incidence of ICU-acquired bacteremia and with less acquisition of respiratory tract colonization with antibiotic resistant pathogens, compared to standard care. A post-hoc analysis of this study suggests that SDD might be more effective in surgical patients and SOD in nonsurgical patients. In a randomized study perioperative use of SDD in patients undergoing gastrointestinal surgery was associated with lower incidences of anastomotic leakages. A Cochrane meta-analysis, not including any of the before mentioned studies, reported a reduction of respiratory tract infections in studies by using topical antibiotics only and higher survival rates when topical antibiotics were combined with parenteral antibiotics. Recent studies show that in ICUs with low levels of antibiotic resistance, SDD and SOD improved patient outcome and reduced infections and carriage with antibiotic-resistant pathogens. The effect in settings with higher levels of antibiotic resistance remains to be determined as well as the efficacy of SDD and SOD in specific patient groups.

There is room for selection in a small local pig breed when using optimum contribution selection: a simulation study.

PubMed

Gourdine, J L; Sørensen, A C; Rydhmer, L

2012-01-01

Selection progress must be carefully balanced against the conservation of genetic variation in small populations of local breeds. Well-defined breeding programs with specified selection traits are rare in local pig breeds. Given the small population size, the focus is often on the management of genetic diversity. However, in local breeds, optimum contribution selection can be applied to control the rate of inbreeding and to avoid reduced performance in traits with high market value. The aim of this study was to assess the extent to which a breeding program aiming for improved product quality in a small local breed would be feasible. We used stochastic simulations to compare 25 scenarios. The scenarios differed in size of population, selection intensity of boars, type of selection (random selection, truncation selection based on BLUP breeding values, or optimum contribution selection based on BLUP breeding values), and heritability of the selection trait. It was assumed that the local breed is used in an extensive system for a high-meat-quality market. The simulations showed that in the smallest population (300 female reproducers), inbreeding increased by 0.8% when selection was performed at random. With optimum contribution selection, genetic progress can be achieved that is almost as great as that with truncation selection based on BLUP breeding values (0.2 to 0.5 vs. 0.3 to 0.5 genetic SD, P < 0.05), but at a considerably decreased rate of inbreeding (0.7 to 1.2 vs. 2.3 to 5.7%, P < 0.01). This confirmation of the potential utilization of OCS even in small populations is important in the context of sustainable management and the use of animal genetic resources.

The impact of traffic sign deficit on road traffic accidents in Nigeria.

PubMed

Ezeibe, Christian; Ilo, Chukwudi; Oguonu, Chika; Ali, Alphonsus; Abada, Ifeanyi; Ezeibe, Ezinwanne; Oguonu, Chukwunonso; Abada, Felicia; Izueke, Edwin; Agbo, Humphrey

2018-04-04

This study assesses the impact of traffic sign deficit on road traffic accidents in Nigeria. The participants were 720 commercial vehicle drivers. While simple random sampling was used to select 6 out of 137 federal highways, stratified random sampling was used to select six categories of commercial vehicle drivers. The study used qual-dominant mixed methods approach comprising key informant interviews; group interviews; field observation; policy appraisal and secondary literature on traffic signs. Result shows that the failure of government to provide and maintain traffic signs in order to guide road users through the numerous accident black spots on the highways is the major cause of road accidents in Nigeria. The study argues that provision and maintenance of traffic signs present opportunity to promoting safety on the highways and achieving the sustainable development goals.

Remote sensing leaf water stress in coffee (Coffea arabica) using secondary effects of water absorption and random forests

NASA Astrophysics Data System (ADS)

Chemura, Abel; Mutanga, Onisimo; Dube, Timothy

2017-08-01

Water management is an important component in agriculture, particularly for perennial tree crops such as coffee. Proper detection and monitoring of water stress therefore plays an important role not only in mitigating the associated adverse impacts on crop growth and productivity but also in reducing expensive and environmentally unsustainable irrigation practices. Current methods for water stress detection in coffee production mainly involve monitoring plant physiological characteristics and soil conditions. In this study, we tested the ability of selected wavebands in the VIS/NIR range to predict plant water content (PWC) in coffee using the random forest algorithm. An experiment was set up such that coffee plants were exposed to different levels of water stress and reflectance and plant water content measured. In selecting appropriate parameters, cross-correlation identified 11 wavebands, reflectance difference identified 16 and reflectance sensitivity identified 22 variables related to PWC. Only three wavebands (485 nm, 670 nm and 885 nm) were identified by at least two methods as significant. The selected wavebands were trained (n = 36) and tested on independent data (n = 24) after being integrated into the random forest algorithm to predict coffee PWC. The results showed that the reflectance sensitivity selected bands performed the best in water stress detection (r = 0.87, RMSE = 4.91% and pBias = 0.9%), when compared to reflectance difference (r = 0.79, RMSE = 6.19 and pBias = 2.5%) and cross-correlation selected wavebands (r = 0.75, RMSE = 6.52 and pBias = 1.6). These results indicate that it is possible to reliably predict PWC using wavebands in the VIS/NIR range that correspond with many of the available multispectral scanners using random forests and further research at field and landscape scale is required to operationalize these findings.

A random rule model of surface growth

NASA Astrophysics Data System (ADS)

Mello, Bernardo A.

2015-02-01

Stochastic models of surface growth are usually based on randomly choosing a substrate site to perform iterative steps, as in the etching model, Mello et al. (2001) [5]. In this paper I modify the etching model to perform sequential, instead of random, substrate scan. The randomicity is introduced not in the site selection but in the choice of the rule to be followed in each site. The change positively affects the study of dynamic and asymptotic properties, by reducing the finite size effect and the short-time anomaly and by increasing the saturation time. It also has computational benefits: better use of the cache memory and the possibility of parallel implementation.

[Are there selection criteria between abdominal approach and vaginal route for genital prolapse surgical management?].

PubMed

Cour, F; Vidart, A

2016-07-01

The never ending debate over the surgical approach of genital prolapse repair (abdominal versus vaginal route) is as passionate as ever. The available literature may support a multidisciplinary analysis of our expert daily practice. Our purpose was to define selection criteria for surgical approach between abdominal and vaginal route in the management of genital prolapse by reviewing the literature. Systematically review of the literature concerning comparative anatomical and functionnal results of surgery of pelvic organ prolaps by vaginal or abdominal route. We were confronted to the lack of data in the literature, with few prospective randomized comparative studies. Many limitations were identified such as small populations in the studies, no description of sub-population, multiplicity of surgical procedures. Moreover, vaginal route was compared to sacral colpopexy by open abdominal approach, whereas laparoscopic sacrocolpopexy is now recommended. Only one prospective randomized comparative trial assessed laparoscopic sacrocolpopexy and vaginal approach, in which was used a mesh withdrawn from the market. The lack of available randomized trials makes it impossible to define HAS compliant guidelines on this topic. However, selection criteria for each surgical approach and technique were drawn from experts' advices. © 2016 Published by Elsevier Masson SAS. © 2016 Elsevier Masson SAS. Tous droits réservés.

A large-scale study of the random variability of a coding sequence: a study on the CFTR gene.

PubMed

Modiano, Guido; Bombieri, Cristina; Ciminelli, Bianca Maria; Belpinati, Francesca; Giorgi, Silvia; Georges, Marie des; Scotet, Virginie; Pompei, Fiorenza; Ciccacci, Cinzia; Guittard, Caroline; Audrézet, Marie Pierre; Begnini, Angela; Toepfer, Michael; Macek, Milan; Ferec, Claude; Claustres, Mireille; Pignatti, Pier Franco

2005-02-01

Coding single nucleotide substitutions (cSNSs) have been studied on hundreds of genes using small samples (n(g) approximately 100-150 genes). In the present investigation, a large random European population sample (average n(g) approximately 1500) was studied for a single gene, the CFTR (Cystic Fibrosis Transmembrane conductance Regulator). The nonsynonymous (NS) substitutions exhibited, in accordance with previous reports, a mean probability of being polymorphic (q > 0.005), much lower than that of the synonymous (S) substitutions, but they showed a similar rate of subpolymorphic (q < 0.005) variability. This indicates that, in autosomal genes that may have harmful recessive alleles (nonduplicated genes with important functions), genetic drift overwhelms selection in the subpolymorphic range of variability, making disadvantageous alleles behave as neutral. These results imply that the majority of the subpolymorphic nonsynonymous alleles of these genes are selectively negative or even pathogenic.

THE SELECTION OF A NATIONAL RANDOM SAMPLE OF TEACHERS FOR EXPERIMENTAL CURRICULUM EVALUATION.

ERIC Educational Resources Information Center

WELCH, WAYNE W.; AND OTHERS

MEMBERS OF THE EVALUATION SECTION OF HARVARD PROJECT PHYSICS, DESCRIBING WHAT IS SAID TO BE THE FIRST ATTEMPT TO SELECT A NATIONAL RANDOM SAMPLE OF (HIGH SCHOOL PHYSICS) TEACHERS, LIST THE STEPS AS (1) PURCHASE OF A LIST OF PHYSICS TEACHERS FROM THE NATIONAL SCIENCE TEACHERS ASSOCIATION (MOST COMPLETE AVAILABLE), (2) SELECTION OF 136 NAMES BY A…

Rethinking the assessment of risk of bias due to selective reporting: a cross-sectional study.

PubMed

Page, Matthew J; Higgins, Julian P T

2016-07-08

Selective reporting is included as a core domain of Cochrane's tool for assessing risk of bias in randomised trials. There has been no evaluation of review authors' use of this domain. We aimed to evaluate assessments of selective reporting in a cross-section of Cochrane reviews and to outline areas for improvement. We obtained data on selective reporting judgements for 8434 studies included in 586 Cochrane reviews published from issue 1-8, 2015. One author classified the reasons for judgements of high risk of selective reporting bias. We randomly selected 100 reviews with at least one trial rated at high risk of outcome non-reporting bias (non-/partial reporting of an outcome on the basis of its results). One author recorded whether the authors of these reviews incorporated the selective reporting assessment when interpreting results. Of the 8434 studies, 1055 (13 %) were rated at high risk of bias on the selective reporting domain. The most common reason was concern about outcome non-reporting bias. Few studies were rated at high risk because of concerns about bias in selection of the reported result (e.g. reporting of only a subset of measurements, analysis methods or subsets of the data that were pre-specified). Review authors often specified in the risk of bias tables the study outcomes that were not reported (84 % of studies) but less frequently specified the outcomes that were partially reported (61 % of studies). At least one study was rated at high risk of outcome non-reporting bias in 31 % of reviews. In the random sample of these reviews, only 30 % incorporated this information when interpreting results, by acknowledging that the synthesis of an outcome was missing data that were not/partially reported. Our audit of user practice in Cochrane reviews suggests that the assessment of selective reporting in the current risk of bias tool does not work well. It is not always clear which outcomes were selectively reported or what the corresponding risk of bias is in the synthesis with missing outcome data. New tools that will make it easier for reviewers to convey this information are being developed.

Unbiased feature selection in learning random forests for high-dimensional data.

PubMed

Nguyen, Thanh-Tung; Huang, Joshua Zhexue; Nguyen, Thuy Thi

2015-01-01

Random forests (RFs) have been widely used as a powerful classification method. However, with the randomization in both bagging samples and feature selection, the trees in the forest tend to select uninformative features for node splitting. This makes RFs have poor accuracy when working with high-dimensional data. Besides that, RFs have bias in the feature selection process where multivalued features are favored. Aiming at debiasing feature selection in RFs, we propose a new RF algorithm, called xRF, to select good features in learning RFs for high-dimensional data. We first remove the uninformative features using p-value assessment, and the subset of unbiased features is then selected based on some statistical measures. This feature subset is then partitioned into two subsets. A feature weighting sampling technique is used to sample features from these two subsets for building trees. This approach enables one to generate more accurate trees, while allowing one to reduce dimensionality and the amount of data needed for learning RFs. An extensive set of experiments has been conducted on 47 high-dimensional real-world datasets including image datasets. The experimental results have shown that RFs with the proposed approach outperformed the existing random forests in increasing the accuracy and the AUC measures.

Study of The Vector Product using Three Dimensions Vector Card of Engineering in Pathumwan Institute of Technology

NASA Astrophysics Data System (ADS)

Mueanploy, Wannapa

2015-06-01

The objective of this research was to offer the way to improve engineering students in Physics topic of vector product. The sampling of this research was the engineering students at Pathumwan Institute of Technology during the first semester of academic year 2013. 1) Select 120 students by random sampling are asked to fill in a satisfaction questionnaire scale, to select size of three dimensions vector card in order to apply in the classroom. 2) Select 60 students by random sampling to do achievement test and take the test to be used in the classroom. The methods used in analysis of achievement test by the Kuder-Richardson Method (KR- 20). The results show that 12 items of achievement test are appropriate to be applied in the classroom. The achievement test gets Difficulty (P) = 0.40-0.67, Discrimination = 0.33-0.73 and Reliability (r) = 0.70.The experimental in the classroom. 3) Select 60 students by random sampling divide into two groups; group one (the controlled group) with 30 students was chosen to study in the vector product lesson by the regular teaching method. Group two (the experimental group) with 30 students was chosen to learn the vector product lesson with three dimensions vector card. 4) Analyzed data between the controlled group and the experimental group, the result showed that experimental group got higher achievement test than the controlled group significant at .01 level.

Applications of random forest feature selection for fine-scale genetic population assignment.

PubMed

Sylvester, Emma V A; Bentzen, Paul; Bradbury, Ian R; Clément, Marie; Pearce, Jon; Horne, John; Beiko, Robert G

2018-02-01

Genetic population assignment used to inform wildlife management and conservation efforts requires panels of highly informative genetic markers and sensitive assignment tests. We explored the utility of machine-learning algorithms (random forest, regularized random forest and guided regularized random forest) compared with F ST ranking for selection of single nucleotide polymorphisms (SNP) for fine-scale population assignment. We applied these methods to an unpublished SNP data set for Atlantic salmon ( Salmo salar ) and a published SNP data set for Alaskan Chinook salmon ( Oncorhynchus tshawytscha ). In each species, we identified the minimum panel size required to obtain a self-assignment accuracy of at least 90% using each method to create panels of 50-700 markers Panels of SNPs identified using random forest-based methods performed up to 7.8 and 11.2 percentage points better than F ST -selected panels of similar size for the Atlantic salmon and Chinook salmon data, respectively. Self-assignment accuracy ≥90% was obtained with panels of 670 and 384 SNPs for each data set, respectively, a level of accuracy never reached for these species using F ST -selected panels. Our results demonstrate a role for machine-learning approaches in marker selection across large genomic data sets to improve assignment for management and conservation of exploited populations.

High-Tg Polynorbornene-Based Block and Random Copolymers for Butanol Pervaporation Membranes

NASA Astrophysics Data System (ADS)

Register, Richard A.; Kim, Dong-Gyun; Takigawa, Tamami; Kashino, Tomomasa; Burtovyy, Oleksandr; Bell, Andrew

Vinyl addition polymers of substituted norbornene (NB) monomers possess desirably high glass transition temperatures (Tg); however, until very recently, the lack of an applicable living polymerization chemistry has precluded the synthesis of such polymers with controlled architecture, or copolymers with controlled sequence distribution. We have recently synthesized block and random copolymers of NB monomers bearing hydroxyhexafluoroisopropyl and n-butyl substituents (HFANB and BuNB) via living vinyl addition polymerization with Pd-based catalysts. Both series of polymers were cast into the selective skin layers of thin film composite (TFC) membranes, and these organophilic membranes investigated for the isolation of n-butanol from dilute aqueous solution (model fermentation broth) via pervaporation. The block copolymers show well-defined microphase-separated morphologies, both in bulk and as the selective skin layers on TFC membranes, while the random copolymers are homogeneous. Both block and random vinyl addition copolymers are effective as n-butanol pervaporation membranes, with the block copolymers showing a better flux-selectivity balance. While polyHFANB has much higher permeability and n-butanol selectivity than polyBuNB, incorporating BuNB units into the polymer (in either a block or random sequence) limits the swelling of the polyHFANB and thereby improves the n-butanol pervaporation selectivity.

Factors Associated with High Use of a Workplace Web-Based Stress Management Program in a Randomized Controlled Intervention Study

ERIC Educational Resources Information Center

Hasson, H.; Brown, C.; Hasson, D.

2010-01-01

In web-based health promotion programs, large variations in participant engagement are common. The aim was to investigate determinants of high use of a worksite self-help web-based program for stress management. Two versions of the program were offered to randomly selected departments in IT and media companies. A static version of the program…

The quality of reporting of randomized controlled trials of traditional Chinese medicine: a survey of 13 randomly selected journals from mainland China.

PubMed

Wang, Gang; Mao, Bing; Xiong, Ze-Yu; Fan, Tao; Chen, Xiao-Dong; Wang, Lei; Liu, Guan-Jian; Liu, Jia; Guo, Jia; Chang, Jing; Wu, Tai-Xiang; Li, Ting-Qian

2007-07-01

The number of randomized controlled trials (RCTs) of traditional Chinese medicine (TCM) is increasing. However, there have been few systematic assessments of the quality of reporting of these trials. This study was undertaken to evaluate the quality of reporting of RCTs in TCM journals published in mainland China from 1999 to 2004. Thirteen TCM journals were randomly selected by stratified sampling of the approximately 100 TCM journals published in mainland China. All issues of the selected journals published from 1999 to 2004 were hand-searched according to guidelines from the Cochrane Centre. All reviewers underwent training in the evaluation of RCTs at the Chinese Centre of Evidence-based Medicine. A comprehensive quality assessment of each RCT was completed using a modified version of the Consolidated Standards of Reporting Trials (CONSORT) checklist (total of 30 items) and the Jadad scale. Disagreements were resolved by consensus. Seven thousand four hundred twenty-two RCTs were identified. The proportion of published RCTs relative to all types of published clinical trials increased significantly over the period studied, from 18.6% in 1999 to 35.9% in 2004 (P < 0.001). The mean (SD) Jadad score was 1.03 (0.61) overall. One RCT had a Jadad score of 5 points; 14 had a score of 4 points; and 102 had a score of 3 points. The mean (SD) Jadad score was 0.85 (0.53) in 1999 (746 RCTs) and 1.20 (0.62) in 2004 (1634 RCTs). Across all trials, 39.4% of the items on the modified CONSORT checklist were reported, which was equivalent to 11.82 (5.78) of the 30 items. Some important methodologic components of RCTs were incompletely reported, such as sample-size calculation (reported in 1.1% of RCTs), randomization sequence (7.9%), allocation concealment (0.3 %), implementation of the random-allocation sequence (0%), and analysis of intention to treat (0%). The findings of this study indicate that the quality of reporting of RCTs of TCM has improved, but remains poor.

Teaching Semantic Prosody of English Verbs through the DDL Approach and Its Effect on Learners' Vocabulary Choice Appropriateness in a Persian EFL Context

ERIC Educational Resources Information Center

Mansoory, Niloofar; Jafarpour, Mohsen

2014-01-01

This study examined teaching SP of English verbs through the data-driven learning (DDL) approach and its effect on learners' vocabulary choice appropriateness in the Persian English foreign language (EFL) context. In the present study, two male intact classes were selected. One of these two classes was randomly selected as a treatment group and…

Studying the Effectiveness of Combination Therapy (Based on Executive Function and Sensory Integration) Child-Centered on the Symptoms of Attention Deficit/hyperactivity Disorder (ADHD)

ERIC Educational Resources Information Center

Salami, Fatemeh; Ashayeri, Hassan; Estaki, Mahnaz; Farzad, Valiollah; Entezar, Roya Koochak

2017-01-01

The aim of the present study is to examine the effectiveness of combination therapy based on executive function and sensory integration child-centered on ADHD. For this purpose, from among all first, second and third grade primary school students in Shiraz, 40 children were selected. The selected students were randomly assigned in two groups of…

Statistical methods for efficient design of community surveys of response to noise: Random coefficients regression models

NASA Technical Reports Server (NTRS)

Tomberlin, T. J.

1985-01-01

Research studies of residents' responses to noise consist of interviews with samples of individuals who are drawn from a number of different compact study areas. The statistical techniques developed provide a basis for those sample design decisions. These techniques are suitable for a wide range of sample survey applications. A sample may consist of a random sample of residents selected from a sample of compact study areas, or in a more complex design, of a sample of residents selected from a sample of larger areas (e.g., cities). The techniques may be applied to estimates of the effects on annoyance of noise level, numbers of noise events, the time-of-day of the events, ambient noise levels, or other factors. Methods are provided for determining, in advance, how accurately these effects can be estimated for different sample sizes and study designs. Using a simple cost function, they also provide for optimum allocation of the sample across the stages of the design for estimating these effects. These techniques are developed via a regression model in which the regression coefficients are assumed to be random, with components of variance associated with the various stages of a multi-stage sample design.

Robust portfolio selection based on asymmetric measures of variability of stock returns

NASA Astrophysics Data System (ADS)

Chen, Wei; Tan, Shaohua

2009-10-01

This paper addresses a new uncertainty set--interval random uncertainty set for robust optimization. The form of interval random uncertainty set makes it suitable for capturing the downside and upside deviations of real-world data. These deviation measures capture distributional asymmetry and lead to better optimization results. We also apply our interval random chance-constrained programming to robust mean-variance portfolio selection under interval random uncertainty sets in the elements of mean vector and covariance matrix. Numerical experiments with real market data indicate that our approach results in better portfolio performance.

The effects of aquatic therapy on mobility of individuals with neurological diseases: a systematic review.

PubMed

Marinho-Buzelli, Andresa R; Bonnyman, Alison M; Verrier, Mary C

2015-08-01

To summarize evidence on the effects of aquatic therapy on mobility in individuals with neurological diseases. MEDLINE, EMBASE, PsycInfo, CENTRAL, CINAHL, SPORTDiscus, PEDro, PsycBITE and OT Seeker were searched from inception to 15 September 2014. Hand-searching of reference lists was performed in the selected studies. The search included randomized controlled trials and quasi-experimental studies that investigated the use of aquatic therapy and its effect on mobility of adults with neurological diseases. One reviewer screened titles and abstracts of retrieved studies from the search strategy. Two reviewers independently examined the full texts and conducted the study selection, data extraction and quality assessment. A narrative synthesis of data was applied to summarize information from included studies. The Downs and Black Scale was used to assess methodological quality. A total of 116 articles were obtained for full text eligibility. Twenty studies met the specified inclusion criteria: four Randomized Controlled Trials (RCTs), four non-randomized studies and 12 before-and-after tests. Two RCTs (30 patients with stroke in the aquatic therapy groups), three non-randomized studies and three before-and-after studies showed "fair" evidence that aquatic therapy increases dynamic balance in participants with some neurological disorders. One RCT (seven patients with stroke in the aquatic therapy group) and two before-and-after tests (20 patients with multiple sclerosis) demonstrated "fair" evidence on improvement of gait speed after aquatic therapy. Our synthesis showed "fair" evidence supporting the use of aquatic therapy to improve dynamic balance and gait speed in adults with certain neurological conditions. © The Author(s) 2014.

Design, objectives, execution and reporting of published open-label extension studies.

PubMed

Megan, Bowers; Pickering, Ruth M; Weatherall, Mark

2012-04-01

Open-label extension (OLE) studies following blinded randomized controlled trials (RCTs) of pharmaceuticals are increasingly being carried out but do not conform to regulatory standards and questions surround the validity of their evidence. OLE studies are usually discussed as a homogenous group, yet substantial differences in study design still meet the definition of an OLE. We describe published papers reporting OLE studies focussing on stated objectives, design, conduct and reporting. A search of Embase and Medline databases for 1996 to July 2008 revealed 268 papers reporting OLE studies that met our eligibility criteria. A random sample of 50 was selected for detailed review. Over 80% of the studies had efficacy stated as an objective. The most common methods of allocation at the start of the OLE were for all RCT participants to switch to one active treatment or for only participants on the new drug to continue, but in three studies all participants were re-randomized at the start of the OLE. Eligibility criteria and other selection factors resulted in on average of 74% of participants in the preceding RCT(s) enrolling in the OLE and only 57% completed it. Published OLE studies do not form a homogenous group with respect to design or retention of participants, and thus the validity of evidence from an OLE should be judged on an individual basis. The term 'open label' suggests bias through lack of blinding, but slippage in relation to the sample randomized in the preceding RCT may be the more important threat to validity. © 2010 Blackwell Publishing Ltd.

The influence of food abundance, food dispersion and habitat structure on territory selection and size of an Afrotropical terrestrial insectivore

USGS Publications Warehouse

Stanley, Thomas R.; Newmark, William D.

2015-01-01

Most tropical insectivorous birds, unlike their temperate counterparts, hold and defend a feeding and breeding territory year-around. However, our understanding of ecological factors influencing territory selection and size in tropical insectivores is limited. Here we examine three prominent hypotheses relating food abundance, food dispersion (spatial arrangement of food items), and habitat structure to territoriality in the Usambara Thrush Turdus roehli. We first compared leaf-litter macro-invertebrate abundance and dispersion, and habitat structure between territories and random sites. We then examined the relation between these same ecological factors and territory size. Invertebrate abundance and dispersion were sparsely and evenly distributed across our study system and did not vary between territories and random sites. In contrast, habitat structure did vary between territories and random sites indicating the Usambara Thrush selects territories with open understorey and closed overstorey habitat. Invertebrate abundance and dispersion within territories of the Usambara Thrush were not associated with habitat structure. We believe the most likely explanation for the Usambara Thrush’s preference for open understorey and closed overstorey habitat relates to foraging behavior. Using information-theoretic model selection we found that invertebrate abundance was the highest-ranked predictor of territory size and was inversely related, consistent with food value theory of territoriality.

A comparative study of restricted randomization procedures for multiarm trials with equal or unequal treatment allocation ratios.

PubMed

Ryeznik, Yevgen; Sverdlov, Oleksandr

2018-06-04

Randomization designs for multiarm clinical trials are increasingly used in practice, especially in phase II dose-ranging studies. Many new methods have been proposed in the literature; however, there is lack of systematic, head-to-head comparison of the competing designs. In this paper, we systematically investigate statistical properties of various restricted randomization procedures for multiarm trials with fixed and possibly unequal allocation ratios. The design operating characteristics include measures of allocation balance, randomness of treatment assignments, variations in the allocation ratio, and statistical characteristics such as type I error rate and power. The results from the current paper should help clinical investigators select an appropriate randomization procedure for their clinical trial. We also provide a web-based R shiny application that can be used to reproduce all results in this paper and run simulations under additional user-defined experimental scenarios. Copyright © 2018 John Wiley & Sons, Ltd.

Optimizing classification performance in an object-based very-high-resolution land use-land cover urban application

NASA Astrophysics Data System (ADS)

Georganos, Stefanos; Grippa, Tais; Vanhuysse, Sabine; Lennert, Moritz; Shimoni, Michal; Wolff, Eléonore

2017-10-01

This study evaluates the impact of three Feature Selection (FS) algorithms in an Object Based Image Analysis (OBIA) framework for Very-High-Resolution (VHR) Land Use-Land Cover (LULC) classification. The three selected FS algorithms, Correlation Based Selection (CFS), Mean Decrease in Accuracy (MDA) and Random Forest (RF) based Recursive Feature Elimination (RFE), were tested on Support Vector Machine (SVM), K-Nearest Neighbor, and Random Forest (RF) classifiers. The results demonstrate that the accuracy of SVM and KNN classifiers are the most sensitive to FS. The RF appeared to be more robust to high dimensionality, although a significant increase in accuracy was found by using the RFE method. In terms of classification accuracy, SVM performed the best using FS, followed by RF and KNN. Finally, only a small number of features is needed to achieve the highest performance using each classifier. This study emphasizes the benefits of rigorous FS for maximizing performance, as well as for minimizing model complexity and interpretation.

Selective epidemic vaccination under the performant routing algorithms

NASA Astrophysics Data System (ADS)

Bamaarouf, O.; Alweimine, A. Ould Baba; Rachadi, A.; EZ-Zahraouy, H.

2018-04-01

Despite the extensive research on traffic dynamics and epidemic spreading, the effect of the routing algorithms strategies on the traffic-driven epidemic spreading has not received an adequate attention. It is well known that more performant routing algorithm strategies are used to overcome the congestion problem. However, our main result shows unexpectedly that these algorithms favor the virus spreading more than the case where the shortest path based algorithm is used. In this work, we studied the virus spreading in a complex network using the efficient path and the global dynamic routing algorithms as compared to shortest path strategy. Some previous studies have tried to modify the routing rules to limit the virus spreading, but at the expense of reducing the traffic transport efficiency. This work proposed a solution to overcome this drawback by using a selective vaccination procedure instead of a random vaccination used often in the literature. We found that the selective vaccination succeeded in eradicating the virus better than a pure random intervention for the performant routing algorithm strategies.

A randomized controlled trial of a community health worker intervention in a population of patients with multiple chronic diseases: Study design and protocol

PubMed Central

Kangovi, Shreya; Mitra, Nandita; Turr, Lindsey; Huo, Hairong; Grande, David; Long, Judith A.

2017-01-01

Upstream interventions – e.g. housing programs and community health worker interventions-address socioeconomic and behavioral factors that influence health outcomes across diseases. Studying these types of interventions in clinical trials raises a methodological challenge: how should researchers measure the effect of an upstream intervention in a sample of patients with different diseases? This paper addresses this question using an illustrative protocol of a randomized controlled trial of collaborative-goal setting versus goal-setting plus community health worker support among patients multiple chronic diseases: diabetes, obesity, hypertension and tobacco dependence. At study enrollment, patients met with their primary care providers to select one of their chronic diseases to focus on during the study, and to collaboratively set a goal for that disease. Patients randomly assigned to a community health worker also received six months of support to address socioeconomic and behavioral barriers to chronic disease control. The primary hypothesis was that there would be differences in patients’ selected chronic disease control as measured by HbA1c, body mass index, systolic blood pressure and cigarettes per day, between the goal-setting alone and community health worker support arms. To test this hypothesis, we will conduct a stratum specific multivariate analysis of variance which allows all patients (regardless of their selected chronic disease) to be included in a single model for the primary outcome. Population health researchers can use this approach to measure clinical outcomes across diseases. PMID:27965180

Adaptive consensus of scale-free multi-agent system by randomly selecting links

NASA Astrophysics Data System (ADS)

Mou, Jinping; Ge, Huafeng

2016-06-01

This paper investigates an adaptive consensus problem for distributed scale-free multi-agent systems (SFMASs) by randomly selecting links, where the degree of each node follows a power-law distribution. The randomly selecting links are based on the assumption that every agent decides to select links among its neighbours according to the received data with a certain probability. Accordingly, a novel consensus protocol with the range of the received data is developed, and each node updates its state according to the protocol. By the iterative method and Cauchy inequality, the theoretical analysis shows that all errors among agents converge to zero, and in the meanwhile, several criteria of consensus are obtained. One numerical example shows the reliability of the proposed methods.

Selective Intercultural Sensitivity to Different Sources of Cultural Identity: Study of Intercultural Sensitivity of Students at Teacher Education Programs of Georgia

ERIC Educational Resources Information Center

Tabatadze, Shalva; Gorgadze, Natia

2018-01-01

Purpose: The purpose of this paper is to assess the intercultural sensitivity of students in teacher educational programs at higher education institutes (HEIs) in Georgia. Design/methodology/approach: This research explored the intercultural sensitivity among 355 randomly selected students in teacher education programs at higher education…

Identification of the Social Development in Early Childhood in Pakistan

ERIC Educational Resources Information Center

Malik, Asif; Sarwar, Muhammad; Khan, Naeemullah

2010-01-01

This study was conducted to identify the social development in early childhood years. It was delimited to eight private schools of Lahore City from the area of Faisal Town and Shadman. Forty students (male and female) were randomly selected as the sample. Five students from Nursery, Prep and grade one were selected from each school. A checklist…

Creating an Awareness of Alternatives to Psycho-Social Situations in Elementary School Children.

ERIC Educational Resources Information Center

LeCapitaine, John E.

This study was designed to determine the effectiveness of 18 selected lessons from Dupont's Toward Affective Development (TAD) program for creating an awareness in students of alternatives to psycho-social situations. Using a sample of 60 subjects randomly selected from 111 sixth-grade students in northwest Wisconsin, two experimental and two…

Predictive Values of Selected Auditory Perceptual Factors in Relation to Measured First Grade Reading Achievement.

ERIC Educational Resources Information Center

McNinch, George

A study was conducted to determine the relationship between auditory perceptual skills and first-grade reading success when readiness and intelligence measures were used in conjunction with auditory skills assessments. Sex differences were also considered. Six boys and six girls were randomly selected from each of 10 first-grade classrooms.…

Effects of Computer-Assisted Instruction on Performance of Senior High School Biology Students in Ghana

ERIC Educational Resources Information Center

Owusu, K. A.; Monney, K. A.; Appiah, J. Y.; Wilmot, E. M.

2010-01-01

This study investigated the comparative efficiency of computer-assisted instruction (CAI) and conventional teaching method in biology on senior high school students. A science class was selected in each of two randomly selected schools. The pretest-posttest non equivalent quasi experimental design was used. The students in the experimental group…

Selected Health Practices Among Ohio's Rural Residents: A Decade of Findings. Research Bulletin 1077.

ERIC Educational Resources Information Center

Phillips, G. Howard; And Others

Seven preventive health measures were studied for purposes of determining Ohio rural residents' level of participation; change in participation between 1962 and 1972; participation by farm and rural nonfarm categories; and level of participation by age, sex, educational attainment, and family size. Randomly selected from 10 of Ohio's 88 counties,…

Extrinsic Motivation as Correlates of Work Attitude of the Nigerian Police Force: Implications for Counselling

ERIC Educational Resources Information Center

Igun, Sylvester Nosakhare

2008-01-01

The study examined Extrinsic motivation as correlates of work attitude of the Nigeria Police Force and its implications for counselling. 300 Police personnel were selected by random sampling technique from six departments that make up police force Headquarters, Abuja. The personnel were selected from each department using simple sampling…

The Interrelationships of Preadolescents' Student Characteristics Influencing Selection of Career Exploration Courses [And Abstract]. Industrial Arts Education Monograph No. 1.

ERIC Educational Resources Information Center

Meehan, Merrill L.

The study investigated the interaction of personal and environmental factors influencing seventh graders' selection of career exploration courses for increased exploration in the eighth grade. A stratified random sample (496 students) was drawn from the Pittsburgh Public School's Occupational, Vocational, and Technical Exploratory Program.…

The Effects of Accelerated Math Utilization on Grade Equivalency Score at a Selected Elementary School

ERIC Educational Resources Information Center

Kariuki, Patrick; Gentry, Christi

2010-01-01

The purpose of this study was to examine the effects of Accelerated Math utilization on students' grade equivalency scores. Twelve students for both experimental and control groups were randomly selected from 37 students enrolled in math in grades four through six. The experimental group consisted of the students who actively participated in…

Factors That Predict Negative Versus Positive Addictions in Offspring: Are Dependent Exercisers Different Than Victims of Other Addictions?

ERIC Educational Resources Information Center

Manning, Terri M.

The study reported here assessed individuals' selection of excessive exercise dependent behaviors as they relate to self-esteem, family environment, and perceptions of family members exhibiting dysfunctional behaviors or addictions. A survey was taken of exercisers from a stratified random sample of competitive triathletes selected from the…

Frequentist Model Averaging in Structural Equation Modelling.

PubMed

Jin, Shaobo; Ankargren, Sebastian

2018-06-04

Model selection from a set of candidate models plays an important role in many structural equation modelling applications. However, traditional model selection methods introduce extra randomness that is not accounted for by post-model selection inference. In the current study, we propose a model averaging technique within the frequentist statistical framework. Instead of selecting an optimal model, the contributions of all candidate models are acknowledged. Valid confidence intervals and a [Formula: see text] test statistic are proposed. A simulation study shows that the proposed method is able to produce a robust mean-squared error, a better coverage probability, and a better goodness-of-fit test compared to model selection. It is an interesting compromise between model selection and the full model.

The prognostic impact of cancer stem-like cell biomarker aldehyde dehydrogenase-1 (ALDH1) in ovarian cancer: A meta-analysis.

PubMed

Ruscito, Ilary; Darb-Esfahani, Silvia; Kulbe, Hagen; Bellati, Filippo; Zizzari, Ilaria Grazia; Rahimi Koshkaki, Hassan; Napoletano, Chiara; Caserta, Donatella; Rughetti, Aurelia; Kessler, Mirjana; Sehouli, Jalid; Nuti, Marianna; Braicu, Elena Ioana

2018-05-10

To investigate the association of cancer stem cell biomarker aldehyde dehydrogenase-1 (ALDH1) with ovarian cancer patients' prognosis and clinico-pathological characteristics. The electronic searches were performed in January 2018 through the databases PubMed, MEDLINE and Scopus by searching the terms: "ovarian cancer" AND "immunohistochemistry" AND ["aldehyde dehydrogenase-1" OR "ALDH1" OR "cancer stem cell"]. Studies evaluating the impact of ALDH1 expression on ovarian cancer survival and clinico-pathological variables were selected. 233 studies were retrieved. Thirteen studies including 1885 patients met all selection criteria. ALDH1-high expression was found to be significantly associated with poor 5-year OS (OR = 3.46; 95% CI: 1.61-7.42; P = 0.001, random effects model) and 5-year PFS (OR = 2.14; 95% CI: 1.11-4.13; P = 0.02, random effects model) in ovarian cancer patients. No correlation between ALDH1 expression and tumor histology (OR = 0.60; 95% CI: 0.36-1.02; P = 0.06, random effects model), FIGO Stage (OR = 0.65; 95% CI: 0.33-1.30; P = 0.22, random effects model), tumor grading (OR = 0.76; 95% CI: 0.40-1.45; P = 0.41, random effects model) lymph nodal status (OR = 2.05; 95% CI: 0.81-5.18; P = 0.13, random effects model) or patients' age at diagnosis (OR = 0.83; 95% CI: 0.54-1.29; P = 0.41, fixed effects model) was identified. Basing on the available evidence, this meta-analysis showed that high levels of ALDH1 expression correlate with worse OS and PFS in ovarian cancer patients. Copyright © 2018. Published by Elsevier Inc.

Reliable Refuge: Two Sky Island Scorpion Species Select Larger, Thermally Stable Retreat Sites.

PubMed

Becker, Jamie E; Brown, Christopher A

2016-01-01

Sky island scorpions shelter under rocks and other surface debris, but, as with other scorpions, it is unclear whether these species select retreat sites randomly. Furthermore, little is known about the thermal preferences of scorpions, and no research has been done to identify whether reproductive condition might influence retreat site selection. The objectives were to (1) identify physical or thermal characteristics for retreat sites occupied by two sky island scorpions (Vaejovis cashi Graham 2007 and V. electrum Hughes 2011) and those not occupied; (2) determine whether retreat site selection differs between the two study species; and (3) identify whether thermal selection differs between species and between gravid and non-gravid females of the same species. Within each scorpion's habitat, maximum dimensions of rocks along a transect line were measured and compared to occupied rocks to determine whether retreat site selection occurred randomly. Temperature loggers were placed under a subset of occupied and unoccupied rocks for 48 hours to compare the thermal characteristics of these rocks. Thermal gradient trials were conducted before parturition and after dispersal of young in order to identify whether gravidity influences thermal preference. Vaejovis cashi and V. electrum both selected larger retreat sites that had more stable thermal profiles. Neither species appeared to have thermal preferences influenced by reproductive condition. However, while thermal selection did not differ among non-gravid individuals, gravid V. electrum selected warmer temperatures than its gravid congener. Sky island scorpions appear to select large retreat sites to maintain thermal stability, although biotic factors (e.g., competition) could also be involved in this choice. Future studies should focus on identifying the various biotic or abiotic factors that could influence retreat site selection in scorpions, as well as determining whether reproductive condition affects thermal selection in other arachnids.

Selective Cannabinoids for Chronic Neuropathic Pain: A Systematic Review and Meta-analysis.

PubMed

Meng, Howard; Johnston, Bradley; Englesakis, Marina; Moulin, Dwight E; Bhatia, Anuj

2017-11-01

There is a lack of consensus on the role of selective cannabinoids for the treatment of neuropathic pain (NP). Guidelines from national and international pain societies have provided contradictory recommendations. The primary objective of this systematic review and meta-analysis (SR-MA) was to determine the analgesic efficacy and safety of selective cannabinoids compared to conventional management or placebo for chronic NP. We reviewed randomized controlled trials that compared selective cannabinoids (dronabinol, nabilone, nabiximols) with conventional treatments (eg, pharmacotherapy, physical therapy, or a combination of these) or placebo in patients with chronic NP because patients with NP may be on any of these therapies or none if all standard treatments have failed to provide analgesia and or if these treatments have been associated with adverse effects. MEDLINE, EMBASE, and other major databases up to March 11, 2016, were searched. Data on scores of numerical rating scale for NP and its subtypes, central and peripheral, were meta-analyzed. The certainty of evidence was classified using the Grade of Recommendations Assessment, Development, and Evaluation approach. Eleven randomized controlled trials including 1219 patients (614 in selective cannabinoid and 605 in comparator groups) were included in this SR-MA. There was variability in the studies in quality of reporting, etiology of NP, type and dose of selective cannabinoids. Patients who received selective cannabinoids reported a significant, but clinically small, reduction in mean numerical rating scale pain scores (0-10 scale) compared with comparator groups (-0.65 points; 95% confidence interval, -1.06 to -0.23 points; P = .002, I = 60%; Grade of Recommendations Assessment, Development, and Evaluation: weak recommendation and moderate-quality evidence). Use of selective cannabinoids was also associated with improvements in quality of life and sleep with no major adverse effects. Selective cannabinoids provide a small analgesic benefit in patients with chronic NP. There was a high degree of heterogeneity among publications included in this SR-MA. Well-designed, large, randomized studies are required to better evaluate specific dosage, duration of intervention, and the effect of this intervention on physical and psychologic function.

Impact of random and systematic recall errors and selection bias in case--control studies on mobile phone use and brain tumors in adolescents (CEFALO study).

PubMed

Aydin, Denis; Feychting, Maria; Schüz, Joachim; Andersen, Tina Veje; Poulsen, Aslak Harbo; Prochazka, Michaela; Klaeboe, Lars; Kuehni, Claudia E; Tynes, Tore; Röösli, Martin

2011-07-01

Whether the use of mobile phones is a risk factor for brain tumors in adolescents is currently being studied. Case--control studies investigating this possible relationship are prone to recall error and selection bias. We assessed the potential impact of random and systematic recall error and selection bias on odds ratios (ORs) by performing simulations based on real data from an ongoing case--control study of mobile phones and brain tumor risk in children and adolescents (CEFALO study). Simulations were conducted for two mobile phone exposure categories: regular and heavy use. Our choice of levels of recall error was guided by a validation study that compared objective network operator data with the self-reported amount of mobile phone use in CEFALO. In our validation study, cases overestimated their number of calls by 9% on average and controls by 34%. Cases also overestimated their duration of calls by 52% on average and controls by 163%. The participation rates in CEFALO were 83% for cases and 71% for controls. In a variety of scenarios, the combined impact of recall error and selection bias on the estimated ORs was complex. These simulations are useful for the interpretation of previous case-control studies on brain tumor and mobile phone use in adults as well as for the interpretation of future studies on adolescents. Copyright © 2011 Wiley-Liss, Inc.

Size differences in migrant sandpiper flocks: ghosts in ephemeral guilds

USGS Publications Warehouse

Eldridge, J.L.; Johnson, D.H.

1988-01-01

Scolopacid sandpipers were studied from 1980 until 1984 during spring migration in North Dakota. Common species foraging together in mixed-species flocks differed in bill length most often by 20 to 30 percent (ratios from 1.2:1 to 1.3:1). Observed flocks were compared to computer generated flocks drawn from three source pools of Arctic-nesting sandpipers. The source pools included 51 migrant species from a global pool, 33 migrant species from a Western Hemisphere pool, and 13 species that migrated through North Dakota. The observed flocks formed randomly from the available species that used the North Dakota migration corridor but the North Dakota species were not a random selection from the Western Hemisphere and global pools of Arctic-nesting scolopacid sandpipers. In short, the ephemeral, mixed-species foraging flocks that we observed in North Dakota were random mixes from a non-random pool. The size-ratio distributions were consistent with the interpretation that use of this migration corridor by sandpipers has been influenced by some form of size-related selection such as competition.

Treatment selection in a randomized clinical trial via covariate-specific treatment effect curves.

PubMed

Ma, Yunbei; Zhou, Xiao-Hua

2017-02-01

For time-to-event data in a randomized clinical trial, we proposed two new methods for selecting an optimal treatment for a patient based on the covariate-specific treatment effect curve, which is used to represent the clinical utility of a predictive biomarker. To select an optimal treatment for a patient with a specific biomarker value, we proposed pointwise confidence intervals for each covariate-specific treatment effect curve and the difference between covariate-specific treatment effect curves of two treatments. Furthermore, to select an optimal treatment for a future biomarker-defined subpopulation of patients, we proposed confidence bands for each covariate-specific treatment effect curve and the difference between each pair of covariate-specific treatment effect curve over a fixed interval of biomarker values. We constructed the confidence bands based on a resampling technique. We also conducted simulation studies to evaluate finite-sample properties of the proposed estimation methods. Finally, we illustrated the application of the proposed method in a real-world data set.

Evolving artificial metalloenzymes via random mutagenesis

NASA Astrophysics Data System (ADS)

Yang, Hao; Swartz, Alan M.; Park, Hyun June; Srivastava, Poonam; Ellis-Guardiola, Ken; Upp, David M.; Lee, Gihoon; Belsare, Ketaki; Gu, Yifan; Zhang, Chen; Moellering, Raymond E.; Lewis, Jared C.

2018-03-01

Random mutagenesis has the potential to optimize the efficiency and selectivity of protein catalysts without requiring detailed knowledge of protein structure; however, introducing synthetic metal cofactors complicates the expression and screening of enzyme libraries, and activity arising from free cofactor must be eliminated. Here we report an efficient platform to create and screen libraries of artificial metalloenzymes (ArMs) via random mutagenesis, which we use to evolve highly selective dirhodium cyclopropanases. Error-prone PCR and combinatorial codon mutagenesis enabled multiplexed analysis of random mutations, including at sites distal to the putative ArM active site that are difficult to identify using targeted mutagenesis approaches. Variants that exhibited significantly improved selectivity for each of the cyclopropane product enantiomers were identified, and higher activity than previously reported ArM cyclopropanases obtained via targeted mutagenesis was also observed. This improved selectivity carried over to other dirhodium-catalysed transformations, including N-H, S-H and Si-H insertion, demonstrating that ArMs evolved for one reaction can serve as starting points to evolve catalysts for others.

Circulating Selenium and Prostate Cancer Risk: A Mendelian Randomization Analysis.

PubMed

Yarmolinsky, James; Bonilla, Carolina; Haycock, Philip C; Langdon, Ryan J Q; Lotta, Luca A; Langenberg, Claudia; Relton, Caroline L; Lewis, Sarah J; Evans, David M; Davey Smith, George; Martin, Richard M

2018-05-17

In the Selenium and Vitamin E Cancer Prevention Trial (SELECT), selenium supplementation (causing a median 114 μg/L increase in circulating selenium) did not lower overall prostate cancer risk, but increased risk of high-grade prostate cancer and type 2 diabetes. Mendelian randomization analysis uses genetic variants to proxy modifiable risk factors and can strengthen causal inference in observational studies. We constructed a genetic instrument comprising 11 single nucleotide polymorphisms robustly (P < 5 × 10-8) associated with circulating selenium in genome-wide association studies. In a Mendelian randomization analysis of 72 729 men in the PRACTICAL Consortium (44 825 case subjects, 27 904 control subjects), 114 μg/L higher genetically elevated circulating selenium was not associated with prostate cancer (odds ratio [OR] = 1.01, 95% confidence interval [CI] = 0.89 to 1.13). In concordance with findings from SELECT, selenium was weakly associated with advanced (including high-grade) prostate cancer (OR = 1.21, 95% CI = 0.98 to 1.49) and type 2 diabetes (OR = 1.18, 95% CI = 0.97 to 1.43; in a type 2 diabetes genome-wide association study meta-analysis with up to 49 266 case subjects and 249 906 control subjects). Our Mendelian randomization analyses do not support a role for selenium supplementation in prostate cancer prevention and suggest that supplementation could have adverse effects on risks of advanced prostate cancer and type 2 diabetes.

Dual-state modulation of the contextual cueing effect: Evidence from eye movement recordings.

PubMed

Zhao, Guang; Liu, Qiang; Jiao, Jun; Zhou, Peiling; Li, Hong; Sun, Hong-jin

2012-06-08

The repeated configurations of random elements induce a better search performance than that of the displays of novel random configurations. The mechanism of such contextual cueing effect has been investigated through the use of the RT × Set Size function. There are divergent views on whether the contextual cueing effect is driven by attentional guidance or facilitation of initial perceptual processing or response selection. To explore this question, we used eye movement recording in this study, which offers information about the substages of the search task. The results suggest that the contextual cueing effect is contributed mainly by attentional guidance, and facilitation of response selection also plays a role.

Informed Consent to Study Purpose in Randomized Clinical Trials of Antibiotics, 1991 Through 2011.

PubMed

Doshi, Peter; Hur, Peter; Jones, Mark; Albarmawi, Husam; Jefferson, Tom; Morgan, Daniel J; Spears, Patricia A; Powers, John H

2017-10-01

Potential research participants may assume that randomized trials comparing new interventions with older interventions always hypothesize greater efficacy for the new intervention, as in superiority trials. However, antibiotic trials frequently use "noninferiority" hypotheses allowing a degree of inferior efficacy deemed "clinically acceptable" compared with an older effective drug, in exchange for nonefficacy benefits (eg, decreased adverse effects). Considering these different benefit-harm trade-offs, proper informed consent necessitates supplying different information on the purposes of superiority and noninferiority trials. To determine the degree to which the study purpose is explained to potential participants in randomized clinical trials of antibiotics and the degree to which study protocols justify their selection of noninferiority hypotheses and amount of "clinically acceptable" inferiority. Cross-sectional analysis of study protocols, statistical analysis plans (SAPs), and informed consent forms (ICFs) from clinical study reports submitted to the European Medicines Agency. The ICFs were read by both methodologists and patient investigators. Protocols and SAPs were used as the reference standard to determine prespecified primary hypothesis and record rationale for selection of noninferiority hypotheses and noninferiority margins. This information was cross-referenced against ICFs to determine whether ICFs explained the study purpose. We obtained trial documents from 78 randomized trials with prespecified efficacy hypotheses (6 superiority, 72 noninferiority) for 17 antibiotics conducted between 1991 and 2011 that enrolled 39 407 patients. Fifty were included in the ICF analysis. All ICFs contained sections describing study purpose; however, none consistently conveyed study hypothesis to both methodologists and patient investigators. Methodologists found that 1 of 50 conveyed a study purpose. Patient investigators found that 11 of 50 conveyed a study purpose, 7 accurately and 4 inaccurately compared with the reference standard. Seventy-one of 72 noninferiority trial protocols or SAPs provided no rationale for selection of noninferiority hypothesis. None provided a clinical rationale for the chosen amount of decreased efficacy. Patients were not accurately informed of study purpose, which raises questions regarding the ethics of informed consent in antibiotic trials. Noninferiority and superiority trials entail different benefit-harm trade-offs that must be conveyed for ethical informed consent.

Refernce Conditions for Streams in the Grand Prairie Natural Division of Illinois

NASA Astrophysics Data System (ADS)

Sangunett, B.; Dewalt, R.

2005-05-01

As part of the Critical Trends Assessment Program (CTAP) of the Illinois Department of Natural Resources (IDNR), 12 potential reference quality stream sites in the Grand Prairie Natural Division were evaluated in May 2004. This agriculturally dominated region, located in east central Illinois, is the most highly modified in the state. The quality of these sites was assessed using a modified Hilsenhoff Biotic Index and species richness of Ephemeroptera, Plecoptera, and Trichoptera (EPT) insect orders and a 12 parameter Habitat Quality Index (HQI). Illinois EPA high quality fish stations, Illinois Natural History Survey insect collection data, and best professional knowledge were used to choose which streams to evaluate. For analysis, reference quality streams were compared to 37 randomly selected meandering streams and 26 randomly selected channelized streams which were assessed by CTAP between 1997 and 2001. The results showed that the reference streams exceeded both taxa richness and habitat quality of randomly selected streams in the region. Both random meandering sites and reference quality sites increased in taxa richness and HQI as stream width increased. Randomly selected channelized streams had about the same taxa richness and HQI regardless of width.

Key Aspects of Nucleic Acid Library Design for in Vitro Selection

PubMed Central

Vorobyeva, Maria A.; Davydova, Anna S.; Vorobjev, Pavel E.; Pyshnyi, Dmitrii V.; Venyaminova, Alya G.

2018-01-01

Nucleic acid aptamers capable of selectively recognizing their target molecules have nowadays been established as powerful and tunable tools for biospecific applications, be it therapeutics, drug delivery systems or biosensors. It is now generally acknowledged that in vitro selection enables one to generate aptamers to almost any target of interest. However, the success of selection and the affinity of the resulting aptamers depend to a large extent on the nature and design of an initial random nucleic acid library. In this review, we summarize and discuss the most important features of the design of nucleic acid libraries for in vitro selection such as the nature of the library (DNA, RNA or modified nucleotides), the length of a randomized region and the presence of fixed sequences. We also compare and contrast different randomization strategies and consider computer methods of library design and some other aspects. PMID:29401748

2013–2014 National Roadside Study of alcohol and drug use by drivers: drug results.

DOT National Transportation Integrated Search

2017-05-01

This was a nationally representative study to estimate the prevalence of alcohol and other drug use among drivers. : Drugs studied included 98 over-the-counter, prescription, and illegal substances. Drivers were randomly selected at : 60 sites (300 l...

Sampling designs for HIV molecular epidemiology with application to Honduras.

PubMed

Shepherd, Bryan E; Rossini, Anthony J; Soto, Ramon Jeremias; De Rivera, Ivette Lorenzana; Mullins, James I

2005-11-01

Proper sampling is essential to characterize the molecular epidemiology of human immunodeficiency virus (HIV). HIV sampling frames are difficult to identify, so most studies use convenience samples. We discuss statistically valid and feasible sampling techniques that overcome some of the potential for bias due to convenience sampling and ensure better representation of the study population. We employ a sampling design called stratified cluster sampling. This first divides the population into geographical and/or social strata. Within each stratum, a population of clusters is chosen from groups, locations, or facilities where HIV-positive individuals might be found. Some clusters are randomly selected within strata and individuals are randomly selected within clusters. Variation and cost help determine the number of clusters and the number of individuals within clusters that are to be sampled. We illustrate the approach through a study designed to survey the heterogeneity of subtype B strains in Honduras.

Quality of different in-clinic test systems for feline immunodeficiency virus and feline leukaemia virus infection.

PubMed

Hartmann, Katrin; Griessmayr, Pascale; Schulz, Bianka; Greene, Craig E; Vidyashankar, Anand N; Jarrett, Os; Egberink, Herman F

2007-12-01

Many new diagnostic in-house tests for identification of feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) infection have been licensed for use in veterinary practice, and the question of the relative merits of these kits has prompted comparative studies. This study was designed to define the strengths and weaknesses of seven FIV and eight FeLV tests that are commercially available. In this study, 536 serum samples from randomly selected cats were tested. Those samples reacting FIV-positive in at least one of the tests were confirmed by Western blot, and those reacting FeLV-positive were confirmed by virus isolation. In addition, a random selection of samples testing negative in all test systems was re-tested by Western blot (100 samples) and by virus isolation (81 samples). Specificity, sensitivity, positive and negative predictive values of each test and the quality of the results were compared.

Methods and analysis of realizing randomized grouping.

PubMed

Hu, Liang-Ping; Bao, Xiao-Lei; Wang, Qi

2011-07-01

Randomization is one of the four basic principles of research design. The meaning of randomization includes two aspects: one is to randomly select samples from the population, which is known as random sampling; the other is to randomly group all the samples, which is called randomized grouping. Randomized grouping can be subdivided into three categories: completely, stratified and dynamically randomized grouping. This article mainly introduces the steps of complete randomization, the definition of dynamic randomization and the realization of random sampling and grouping by SAS software.

Selection of habitats by Emperor Geese during brood rearing

USGS Publications Warehouse

Schmutz, J.A.

2001-01-01

Although forage quality strongly affects gosling growth and consequently juvenile survival, the relative use of different plant communities by brood rearing geese has been poorly studied. On the Yukon-Kuskokwim Delta, Alaska, population growth and juvenile recruitment of Emperor Geese (Chen canagica) are comparatively low, and it is unknown whether their selection of habitats during brood rearing differs from other goose species. Radio-telemetry was used to document the use of habitats by 56 families of Emperor Geese in a 70 km2 portion of the Yukon-Kuskokwim Delta during brood rearing in 1994-1996. When contrasted with available habitats (a set of six habitat classes), as estimated from 398 random sampling locations, Emperor Geese strongly selected Saline Ponds, Mudflat, and Ramenskii Meadow habitats and avoided Levee Meadow, Bog Meadow, and Sedge Meadow. These selected habitats were the most saline, comprised one-third of the study area, and 43% of all locations were in Ramenskii Meadow. I contrasted these Emperor Goose locations with habitats used by the composite goose community, as inferred from the presence of goose feces at random locations. The marked difference between groups in this comparison implied that Cackling Canada Geese (Branta canadensis minima) and Greater White-fronted Geese (Anser albifrons) collectively selected much different brood rearing habitats than Emperor Geese. Received 20 February 2001, accepted 18 April 2001.

Feature-selective attention: evidence for a decline in old age.

PubMed

Quigley, Cliodhna; Andersen, Søren K; Schulze, Lars; Grunwald, Martin; Müller, Matthias M

2010-04-19

Although attention in older adults is an active research area, feature-selective aspects have not yet been explicitly studied. Here we report the results of an exploratory study involving directed changes in feature-selective attention. The stimuli used were two random dot kinematograms (RDKs) of different colours, superimposed and centrally presented. A colour cue with random onset after the beginning of each trial instructed young and older subjects to attend to one of the RDKs and detect short intervals of coherent motion while ignoring analogous motion events in the non-cued RDK. Behavioural data show that older adults could detect motion, but discriminated target from distracter motion less reliably than young adults. The method of frequency tagging allowed us to separate the EEG responses to the attended and ignored stimuli and directly compare steady-state visual evoked potential (SSVEP) amplitudes elicited by each stimulus before and after cue onset. We found that younger adults show a clear attentional enhancement of SSVEP amplitude in the post-cue interval, while older adults' SSVEP responses to attended and ignored stimuli do not differ. Thus, in situations where attentional selection cannot be spatially resolved, older adults show a deficit in selection that is not shared by young adults. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

Using Mahalanobis Distance Scores for Matched Pairing of Schools in a Randomized Controlled Trial Study of Leadership and Assistance for Science Education Reform (LASER)

ERIC Educational Resources Information Center

Zoblotsky, Todd; Ransford-Kaldon, Carolyn; Morrison, Donald M.

2011-01-01

The present paper describes the recruitment and site selection process that has been underway since January 2011, with particular emphasis on the use of Mahalanobis distance score to determine matched pairs of sites prior to randomization to treatment and control groups. Through a systematic winnowing process, the authors found that they could…

The Effectiveness of Conflict Maps and the V-Shape Teaching Method in Science Conceptual Change among Eighth-Grade Students in Jordan

ERIC Educational Resources Information Center

Bawaneh, Ali Khalid Ali; Zain, Ahmad Nurulazam Md; Ghazali, Munirah

2010-01-01

The purpose of the present study is to investigate the effectiveness of Conflict Maps and the V-Shape method as teaching methods in bringing about conceptual change in science among primary eighth-grade students in Jordan. A randomly selected sample (N = 63) from the Bani Kenana region North of Jordan was randomly assigned to the two teaching…

Training set selection for the prediction of essential genes.

PubMed

Cheng, Jian; Xu, Zhao; Wu, Wenwu; Zhao, Li; Li, Xiangchen; Liu, Yanlin; Tao, Shiheng

2014-01-01

Various computational models have been developed to transfer annotations of gene essentiality between organisms. However, despite the increasing number of microorganisms with well-characterized sets of essential genes, selection of appropriate training sets for predicting the essential genes of poorly-studied or newly sequenced organisms remains challenging. In this study, a machine learning approach was applied reciprocally to predict the essential genes in 21 microorganisms. Results showed that training set selection greatly influenced predictive accuracy. We determined four criteria for training set selection: (1) essential genes in the selected training set should be reliable; (2) the growth conditions in which essential genes are defined should be consistent in training and prediction sets; (3) species used as training set should be closely related to the target organism; and (4) organisms used as training and prediction sets should exhibit similar phenotypes or lifestyles. We then analyzed the performance of an incomplete training set and an integrated training set with multiple organisms. We found that the size of the training set should be at least 10% of the total genes to yield accurate predictions. Additionally, the integrated training sets exhibited remarkable increase in stability and accuracy compared with single sets. Finally, we compared the performance of the integrated training sets with the four criteria and with random selection. The results revealed that a rational selection of training sets based on our criteria yields better performance than random selection. Thus, our results provide empirical guidance on training set selection for the identification of essential genes on a genome-wide scale.

Phage display peptide libraries: deviations from randomness and correctives

PubMed Central

Ryvkin, Arie; Ashkenazy, Haim; Weiss-Ottolenghi, Yael; Piller, Chen; Pupko, Tal; Gershoni, Jonathan M

2018-01-01

Abstract Peptide-expressing phage display libraries are widely used for the interrogation of antibodies. Affinity selected peptides are then analyzed to discover epitope mimetics, or are subjected to computational algorithms for epitope prediction. A critical assumption for these applications is the random representation of amino acids in the initial naïve peptide library. In a previous study, we implemented next generation sequencing to evaluate a naïve library and discovered severe deviations from randomness in UAG codon over-representation as well as in high G phosphoramidite abundance causing amino acid distribution biases. In this study, we demonstrate that the UAG over-representation can be attributed to the burden imposed on the phage upon the assembly of the recombinant Protein 8 subunits. This was corrected by constructing the libraries using supE44-containing bacteria which suppress the UAG driven abortive termination. We also demonstrate that the overabundance of G stems from variant synthesis-efficiency and can be corrected using compensating oligonucleotide-mixtures calibrated by mass spectroscopy. Construction of libraries implementing these correctives results in markedly improved libraries that display random distribution of amino acids, thus ensuring that enriched peptides obtained in biopanning represent a genuine selection event, a fundamental assumption for phage display applications. PMID:29420788

Selection indicates preference in diverse habitats: A Ground-Nesting bird (charadrius melodus) using reservoir shoreline

USGS Publications Warehouse

Anteau, M.J.; Sherfy, M.H.; Wiltermuth, M.T.

2012-01-01

Animals use proximate cues to select resources that maximize individual fitness. When animals have a diverse array of available habitats, those selected could give insights into true habitat preferences. Since the construction of the Garrison Dam on the Missouri River in North Dakota, Lake Sakakawea (SAK) has become an important breeding area for federally threatened piping plovers (Charadrius melodus; hereafter plovers). We used conditional logistic regression to examine nest-site selection at fine scales (1, 3, and 10 m) during summers 2006-2009 by comparing characteristics at 351 nests to those of 668 random sites within nesting territories. Plovers selected sites (1 m 2) that were lower than unused random sites, increasing the risk of nest inundation. Plovers selected nest sites that were flat, had little silt, and at least 1 cobble; they also selected for 3-m radius nest areas that were relatively flat and devoid of vegetation and litter. Ninety percent of nests had <38% coverage of silt and <10% slope at the site, and <15% coverage of vegetation or litter and <31% slope within the 3-m radius. Gravel was selected for at nest sites (11% median), but against in the area 10-m from the nest, suggesting plovers select for patches or strips of gravel. Although elevation is rarely evaluated in studies of ground-nesting birds, our results underscore its importance in habitat-selection studies. Relative to where plovers historically nested, habitat at SAK has more diverse topography, substrate composition, vegetation communities, and greater water-level fluctuations. Accordingly, our results provide an example of how habitat-selection results can be interpreted as habitat preferences because they are not influenced by desired habitats being scarce or absent. Further, our results will be useful for directing habitat conservation for plovers and interpreting other habitat-selection studies.

Selection indicates preference in diverse habitats: A ground-nesting bird (Charadrius melodus) using reservoir shoreline

USGS Publications Warehouse

Anteau, Michael J.; Sherfy, Mark H.; Wiltermuth, Mark T.

2012-01-01

Animals use proximate cues to select resources that maximize individual fitness. When animals have a diverse array of available habitats, those selected could give insights into true habitat preferences. Since the construction of the Garrison Dam on the Missouri River in North Dakota, Lake Sakakawea (SAK) has become an important breeding area for federally threatened piping plovers (Charadrius melodus; hereafter plovers). We used conditional logistic regression to examine nest-site selection at fine scales (1, 3, and 10 m) during summers 2006–2009 by comparing characteristics at 351 nests to those of 668 random sites within nesting territories. Plovers selected sites (1 m2) that were lower than unused random sites, increasing the risk of nest inundation. Plovers selected nest sites that were flat, had little silt, and at least 1 cobble; they also selected for 3-m radius nest areas that were relatively flat and devoid of vegetation and litter. Ninety percent of nests had <38% coverage of silt and <10% slope at the site, and <15% coverage of vegetation or litter and <31% slope within the 3-m radius. Gravel was selected for at nest sites (11% median), but against in the area 10-m from the nest, suggesting plovers select for patches or strips of gravel. Although elevation is rarely evaluated in studies of ground-nesting birds, our results underscore its importance in habitat-selection studies. Relative to where plovers historically nested, habitat at SAK has more diverse topography, substrate composition, vegetation communities, and greater water-level fluctuations. Accordingly, our results provide an example of how habitat-selection results can be interpreted as habitat preferences because they are not influenced by desired habitats being scarce or absent. Further, our results will be useful for directing habitat conservation for plovers and interpreting other habitat-selection studies.

Selection indicates preference in diverse habitats: a ground-nesting bird (Charadrius melodus) using reservoir shoreline.

PubMed

Anteau, Michael J; Sherfy, Mark H; Wiltermuth, Mark T

2012-01-01

Animals use proximate cues to select resources that maximize individual fitness. When animals have a diverse array of available habitats, those selected could give insights into true habitat preferences. Since the construction of the Garrison Dam on the Missouri River in North Dakota, Lake Sakakawea (SAK) has become an important breeding area for federally threatened piping plovers (Charadrius melodus; hereafter plovers). We used conditional logistic regression to examine nest-site selection at fine scales (1, 3, and 10 m) during summers 2006-2009 by comparing characteristics at 351 nests to those of 668 random sites within nesting territories. Plovers selected sites (1 m(2)) that were lower than unused random sites, increasing the risk of nest inundation. Plovers selected nest sites that were flat, had little silt, and at least 1 cobble; they also selected for 3-m radius nest areas that were relatively flat and devoid of vegetation and litter. Ninety percent of nests had <38% coverage of silt and <10% slope at the site, and <15% coverage of vegetation or litter and <31% slope within the 3-m radius. Gravel was selected for at nest sites (11% median), but against in the area 10-m from the nest, suggesting plovers select for patches or strips of gravel. Although elevation is rarely evaluated in studies of ground-nesting birds, our results underscore its importance in habitat-selection studies. Relative to where plovers historically nested, habitat at SAK has more diverse topography, substrate composition, vegetation communities, and greater water-level fluctuations. Accordingly, our results provide an example of how habitat-selection results can be interpreted as habitat preferences because they are not influenced by desired habitats being scarce or absent. Further, our results will be useful for directing habitat conservation for plovers and interpreting other habitat-selection studies.

Selection Indicates Preference in Diverse Habitats: A Ground-Nesting Bird (Charadrius melodus) Using Reservoir Shoreline

PubMed Central

Anteau, Michael J.; Sherfy, Mark H.; Wiltermuth, Mark T.

2012-01-01

Animals use proximate cues to select resources that maximize individual fitness. When animals have a diverse array of available habitats, those selected could give insights into true habitat preferences. Since the construction of the Garrison Dam on the Missouri River in North Dakota, Lake Sakakawea (SAK) has become an important breeding area for federally threatened piping plovers (Charadrius melodus; hereafter plovers). We used conditional logistic regression to examine nest-site selection at fine scales (1, 3, and 10 m) during summers 2006–2009 by comparing characteristics at 351 nests to those of 668 random sites within nesting territories. Plovers selected sites (1 m2) that were lower than unused random sites, increasing the risk of nest inundation. Plovers selected nest sites that were flat, had little silt, and at least 1 cobble; they also selected for 3-m radius nest areas that were relatively flat and devoid of vegetation and litter. Ninety percent of nests had <38% coverage of silt and <10% slope at the site, and <15% coverage of vegetation or litter and <31% slope within the 3-m radius. Gravel was selected for at nest sites (11% median), but against in the area 10-m from the nest, suggesting plovers select for patches or strips of gravel. Although elevation is rarely evaluated in studies of ground-nesting birds, our results underscore its importance in habitat-selection studies. Relative to where plovers historically nested, habitat at SAK has more diverse topography, substrate composition, vegetation communities, and greater water-level fluctuations. Accordingly, our results provide an example of how habitat-selection results can be interpreted as habitat preferences because they are not influenced by desired habitats being scarce or absent. Further, our results will be useful for directing habitat conservation for plovers and interpreting other habitat-selection studies. PMID:22299037

Outdoor Play and Learning: Policy and Practice

ERIC Educational Resources Information Center

Burriss, Kathleen; Burriss, Larry

2011-01-01

This study describes national school district policy and practice regarding elementary school children's outdoor learning and play. District representatives from 173 randomly selected school districts completed questionnaires describing policy and practice related to recess, outdoor play, outdoor curricular studies, playground materials, ADA…

Assessing the accuracy and stability of variable selection methods for random forest modeling in ecology

EPA Science Inventory

Random forest (RF) modeling has emerged as an important statistical learning method in ecology due to its exceptional predictive performance. However, for large and complex ecological datasets there is limited guidance on variable selection methods for RF modeling. Typically, e...

Results from 2 proof-of-concept, placebo-controlled studies of atomoxetine in children with attention-deficit/hyperactivity disorder.

PubMed

Spencer, Thomas; Heiligenstein, John H; Biederman, Joseph; Faries, Douglas E; Kratochvil, Christopher J; Conners, C Keith; Potter, William Z

2002-12-01

Atomoxetine is a nonstimulant drug being studied for the treatment of attention-deficit/hyperactivity disorder (ADHD). Atomoxetine is a highly specific inhibitor of the presynaptic norepinephrine transporter with minimal affinity for other noradrenergic receptors or other neurotransmitter transporters or receptors. Results of 2 proof-of-concept studies are reported that tested the hypothesis that a selective inhibitor of presynaptic norepinephrine uptake would be effective for the treatment of ADHD in school-aged children. Two identical 12-week, stratified, randomized, double-blind, placebo-controlled trials were conducted in children who met DSM-IV criteria for ADHD. The primary efficacy outcome measure was the mean change from baseline to endpoint in the Attention-Deficit/Hyperactivity Disorder Rating Scale (ADHD RS) total score. Secondary efficacy measures included the Clinical Global Impressions-ADHD-Severity (CGI-ADHD-S) and the Conners' Parent Rating Scale-Revised: Short Form (CPRS-R:S). A total of 291 patients were randomized in the 2 trials combined (Study 1, N = 147; Study 2, N = 144). Stimulant-naive patients were randomized to atomoxetine, placebo, or methylphenidate. Patients with prior stimulant exposure were randomized to atomoxetine or placebo. Atomoxetine significantly reduced ADHD RS total scores compared with placebo in each study (p <.001). Changes in the CGI-ADHD-S (Study 1: p =.003; Study 2: p =.001) and CPRS-ADHD Index (Study 1: p =.023; Study 2: p <.001) also showed atomoxetine to be statistically significantly superior to placebo in reducing ADHD symptoms. Atomoxetine was found to be well tolerated in this population of pediatric patients. Two studies of atomoxetine early in its development confirmed that atomoxetine, a specific and selective inhibitor of noradrenergic uptake, was effective for the treatment of children with ADHD. In addition, atomoxetine was found to be well tolerated.

Genetic improvement in mastitis resistance: comparison of selection criteria from cross-sectional and random regression sire models for somatic cell score.

PubMed

Odegård, J; Klemetsdal, G; Heringstad, B

2005-04-01

Several selection criteria for reducing incidence of mastitis were developed from a random regression sire model for test-day somatic cell score (SCS). For comparison, sire transmitting abilities were also predicted based on a cross-sectional model for lactation mean SCS. Only first-crop daughters were used in genetic evaluation of SCS, and the different selection criteria were compared based on their correlation with incidence of clinical mastitis in second-crop daughters (measured as mean daughter deviations). Selection criteria were predicted based on both complete and reduced first-crop daughter groups (261 or 65 daughters per sire, respectively). For complete daughter groups, predicted transmitting abilities at around 30 d in milk showed the best predictive ability for incidence of clinical mastitis, closely followed by average predicted transmitting abilities over the entire lactation. Both of these criteria were derived from the random regression model. These selection criteria improved accuracy of selection by approximately 2% relative to a cross-sectional model. However, for reduced daughter groups, the cross-sectional model yielded increased predictive ability compared with the selection criteria based on the random regression model. This result may be explained by the cross-sectional model being more robust, i.e., less sensitive to precision of (co)variance components estimates and effects of data structure.

Most Undirected Random Graphs Are Amplifiers of Selection for Birth-Death Dynamics, but Suppressors of Selection for Death-Birth Dynamics.

PubMed

Hindersin, Laura; Traulsen, Arne

2015-11-01

We analyze evolutionary dynamics on graphs, where the nodes represent individuals of a population. The links of a node describe which other individuals can be displaced by the offspring of the individual on that node. Amplifiers of selection are graphs for which the fixation probability is increased for advantageous mutants and decreased for disadvantageous mutants. A few examples of such amplifiers have been developed, but so far it is unclear how many such structures exist and how to construct them. Here, we show that almost any undirected random graph is an amplifier of selection for Birth-death updating, where an individual is selected to reproduce with probability proportional to its fitness and one of its neighbors is replaced by that offspring at random. If we instead focus on death-Birth updating, in which a random individual is removed and its neighbors compete for the empty spot, then the same ensemble of graphs consists of almost only suppressors of selection for which the fixation probability is decreased for advantageous mutants and increased for disadvantageous mutants. Thus, the impact of population structure on evolutionary dynamics is a subtle issue that will depend on seemingly minor details of the underlying evolutionary process.

Accounting for selection bias in association studies with complex survey data.

PubMed

Wirth, Kathleen E; Tchetgen Tchetgen, Eric J

2014-05-01

Obtaining representative information from hidden and hard-to-reach populations is fundamental to describe the epidemiology of many sexually transmitted diseases, including HIV. Unfortunately, simple random sampling is impractical in these settings, as no registry of names exists from which to sample the population at random. However, complex sampling designs can be used, as members of these populations tend to congregate at known locations, which can be enumerated and sampled at random. For example, female sex workers may be found at brothels and street corners, whereas injection drug users often come together at shooting galleries. Despite the logistical appeal, complex sampling schemes lead to unequal probabilities of selection, and failure to account for this differential selection can result in biased estimates of population averages and relative risks. However, standard techniques to account for selection can lead to substantial losses in efficiency. Consequently, researchers implement a variety of strategies in an effort to balance validity and efficiency. Some researchers fully or partially account for the survey design, whereas others do nothing and treat the sample as a realization of the population of interest. We use directed acyclic graphs to show how certain survey sampling designs, combined with subject-matter considerations unique to individual exposure-outcome associations, can induce selection bias. Finally, we present a novel yet simple maximum likelihood approach for analyzing complex survey data; this approach optimizes statistical efficiency at no cost to validity. We use simulated data to illustrate this method and compare it with other analytic techniques.

Single embryo transfer by Day 3 time-lapse selection versus Day 5 conventional morphological selection: a randomized, open-label, non-inferiority trial.

PubMed

Yang, Lanlin; Cai, Sufen; Zhang, Shuoping; Kong, Xiangyi; Gu, Yifan; Lu, Changfu; Dai, Jing; Gong, Fei; Lu, Guangxiu; Lin, Ge

2018-05-01

Does single cleavage-stage (Day 3) embryo transfer using a time-lapse (TL) hierarchical classification model achieve comparable ongoing pregnancy rates (OPR) to single blastocyst (Day 5) transfer by conventional morphological (CM) selection? Day 3 single embryo transfer (SET) with a hierarchical classification model had a significantly lower OPR compared with Day 5 SET with CM selection. Cleavage-stage SET is an alternative to blastocyst SET. Time-lapse imaging assists better embryo selection, based on studies of pregnancy outcomes when adding time-lapse imaging to CM selection at the cleavage or blastocyst stage. This single-centre, randomized, open-label, active-controlled, non-inferiority study included 600 women between October 2015 and April 2017. Eligible patients were Chinese females, aged ≤36 years, who were undergoing their first or second fresh IVF cycle using their own oocytes, and who had FSH levels ≤12 IU/mL on Day 3 of the cycle and 10 or more oocytes retrieved. Patients who had underlying uterine conditions, oocyte donation, recurrent pregnancy loss, abnormal oocytes or <6 normally fertilized embryos (2PN) were excluded from the study participation. Patients were randomized 1:1 to either the cleavage-stage SET with a time-lapse hierarchical classification model for selection (D3 + TL) or blastocyst SET with CM selection (D5 + CM). All normally fertilized zygotes were cultured in Primo Vision. The study was conducted at a tertiary IVF centre (CITIC-Xiangya) and OPR was the primary outcome. A total of 600 patients were randomized to the two groups, among which 585 (D3 + TL = 290, D5 + CM = 295) were included in the Modified-intention-to-treat (mITT) population and 517 (D3 + TL = 261, D5 + CM = 256) were included in the PP population. In the per protocol (PP) population, OPR was significantly lower in the D3 group (59.4%, 155/261) than in the D5 group (68.4%, 175/256) (difference: -9.0%, 95% CI: -17.1%, -0.7%, P = 0.03). Analysis in mITT population showed a marginally significant difference in the OPR between the D3 + TL and D5 + CM groups (56.6 versus 64.1%, difference: -7.5%, 95% CI: -15.4%, 0.4%, P = 0.06). The D3 + TL group resulted in a markedly lower implantation rate than the D5 + CM group (64.4 versus 77.0%; P = 0.002) in the PP analysis, however, the early miscarriage rate did not significantly differ between the two groups. The study lacked a direct comparison between time-lapse and CM selections at cleavage-stage SET and was statistically underpowered to detect non-inferiority. The subject's eligibility criteria favouring women with a good prognosis for IVF weakened the generalizability of the results. The OPR from Day 3 cleavage-stage SET using hierarchical classification time-lapse selection was significantly lower compared with that from Day 5 blastocyst SET using conventional morphology, yet it appeared to be clinically acceptable in women underwent IVF. This study is supported by grants from Ferring Pharmaceuticals and the Program for New Century Excellent Talents in University, China. ChiCTR-ICR-15006600. 16 June 2015. 1 October 2015.

Influence of Counselling Services on Perceived Academic Performance of Secondary School Students in Lagos State

ERIC Educational Resources Information Center

Bolu-Steve, Foluke; Oredugba, Oluwabunmi Olayinka

2017-01-01

This study aimed at looking at the influence of counseling services on perceived academic performance of secondary school students in Lagos State. At the first stage, the researchers purposively selected Ikorodu L.G.A in Lagos State. At the researchers selected two schools (1 Private schools, & 1 Public schools), using simple random technique.…

Effect of Multi Modal Representations on the Critical Thinking Skills of the Fifth Grade Students

ERIC Educational Resources Information Center

Öz, Muhittin; Memis, Esra Kabatas

2018-01-01

The purpose of this study was to explore the effects of multi modal representations within writing to learn activities on students' critical thinking. Mixed method was used. The participants included 32 students 5th grade from elementary school. The groups were randomly selected as a control group and the other class was selected as the…

Parameters of the Teacher Aide Role: A Study of Teacher Aides in Selected Gulf Coast School Districts. Final Report.

ERIC Educational Resources Information Center

DeHart, Ruth

A survey was conducted to provide information of use to school administrators as they plan for initial or continued use of paraprofessional personnel. A questionnaire was developed for use in interviews with 63 principals, supervising teachers and librarians, and teacher aides in 17 randomly selected Texas school districts in the GUSREDA (Gulf…

The use of incentives in vulnerable populations for a telephone survey: a randomized controlled trial.

PubMed

Knoll, Megan; Soller, Lianne; Ben-Shoshan, Moshe; Harrington, Daniel; Fragapane, Joey; Joseph, Lawrence; La Vieille, Sebastien; St-Pierre, Yvan; Wilson, Kathi; Elliott, Susan; Clarke, Ann

2012-10-19

Poor response rates in prevalence surveys can lead to nonresponse bias thereby compromising the validity of prevalence estimates. We conducted a telephone survey of randomly selected households to estimate the prevalence of food allergy in the 10 Canadian provinces between May 2008 and March 2009 (the SCAAALAR study: Surveying Canadians to Assess the Prevalence of Common Food Allergies and Attitudes towards Food LAbeling and Risk). A household response rate of only 34.6% was attained, and those of lower socioeconomic status, lower education and new Canadians were underrepresented. We are now attempting to target these vulnerable populations in the SPAACE study (Surveying the Prevalence of Food Allergy in All Canadian Environments) and are evaluating strategies to increase the response rate. Although the success of incentives to increase response rates has been demonstrated previously, no studies have specifically examined the use of unconditional incentives in these vulnerable populations in a telephone survey. The pilot study will compare response rates between vulnerable Canadian populations receiving and not receiving an incentive. Randomly selected households were randomly assigned to receive either a $5 incentive or no incentive. The between group differences in response rates and 95% confidence intervals (CIs) were calculated. The response rates for the incentive and non-incentive groups were 36.1% and 28.7% respectively, yielding a between group difference of 7.4% (-0.7%, 15.6%). Although the wide CI precludes definitive conclusions, our results suggest that unconditional incentives are effective in vulnerable populations for telephone surveys.

The dilemma of selecting suitable proximal carious lesions in primary molars for restoration using ART technique.

PubMed

Kemoli, A M; van Amerongen, W E

2011-03-01

To determine the examiner's accuracy in selecting proximal carious lesions in primary molars for restoration using the atraumatic restorative treatment (ART) approach. Intervention study. CLINICAL SETTING AND PARTICIPANTS: A total of 804 six to eight year-olds from 30 rural schools in Kenya participated in the study. Three examiners selected a total of 1,280 suitable proximal carious lesions in primary molars after examining 6,002 children from 30 schools randomly selected out of 142 schools in two divisions. Seven operators randomly paired on a daily basis with eight assistants restored the lesions. An explanation was provided for any cavity that was not restored. Pre-and post-operative radiographs of the cavities were also taken for evaluation. The examiner's choice of suitable proximal cavities restorable using the ART approach was related to the decision made to either restore or not during the operative stage. The radiographic findings of the selected cavities were also compared to the decision made by the operator. The results obtained were used to determine the examiner's accuracy in selecting suitable proximal cavities for restoration using the ART approach. The majority of the children recruited in the study were excluded due to absenteeism, pulpal-exposure or anxiety during the operative stage. Only 804 children received one restoration in their primary molars. The examiner's accuracy in selecting suitable ART-restorable cavities clinically was 94.9% and based on radiographic analysis was 91.7%. A trained and diligent examiner has a very good chance of selecting proximal carious lesions restorable with the use of ART approach, without the threat of dental pulpal-involvement during the excavation of caries.

Relationship of Study Habits with Mathematics Achievement

ERIC Educational Resources Information Center

Odiri, Onoshakpokaiye E.

2015-01-01

The study examined the relationship of study habits of students and their achievement in mathematics. The method used for the study was correlation design. A sample of 500 students were randomly selected from 25 public secondary schools in Delta Central Senatorial District, Delta State, Nigeria. Questionnaires were drawn to gather data on…

Random Bits Forest: a Strong Classifier/Regressor for Big Data

NASA Astrophysics Data System (ADS)

Wang, Yi; Li, Yi; Pu, Weilin; Wen, Kathryn; Shugart, Yin Yao; Xiong, Momiao; Jin, Li

2016-07-01

Efficiency, memory consumption, and robustness are common problems with many popular methods for data analysis. As a solution, we present Random Bits Forest (RBF), a classification and regression algorithm that integrates neural networks (for depth), boosting (for width), and random forests (for prediction accuracy). Through a gradient boosting scheme, it first generates and selects ~10,000 small, 3-layer random neural networks. These networks are then fed into a modified random forest algorithm to obtain predictions. Testing with datasets from the UCI (University of California, Irvine) Machine Learning Repository shows that RBF outperforms other popular methods in both accuracy and robustness, especially with large datasets (N > 1000). The algorithm also performed highly in testing with an independent data set, a real psoriasis genome-wide association study (GWAS).

Cluster-Glass Phase in Pyrochlore X Y Antiferromagnets with Quenched Disorder

NASA Astrophysics Data System (ADS)

Andrade, Eric C.; Hoyos, José A.; Rachel, Stephan; Vojta, Matthias

2018-03-01

We study the impact of quenched disorder (random exchange couplings or site dilution) on easy-plane pyrochlore antiferromagnets. In the clean system, order by disorder selects a magnetically ordered state from a classically degenerate manifold. In the presence of randomness, however, different orders can be chosen locally depending on details of the disorder configuration. Using a combination of analytical considerations and classical Monte Carlo simulations, we argue that any long-range-ordered magnetic state is destroyed beyond a critical level of randomness where the system breaks into magnetic domains due to random exchange anisotropies, becoming, therefore, a glass of spin clusters, in accordance with the available experimental data. These random anisotropies originate from off-diagonal exchange couplings in the microscopic Hamiltonian, establishing their relevance to other magnets with strong spin-orbit coupling.

The role of color and attention-to-color in mirror-symmetry perception.

PubMed

Gheorghiu, Elena; Kingdom, Frederick A A; Remkes, Aaron; Li, Hyung-Chul O; Rainville, Stéphane

2016-07-11

The role of color in the visual perception of mirror-symmetry is controversial. Some reports support the existence of color-selective mirror-symmetry channels, others that mirror-symmetry perception is merely sensitive to color-correlations across the symmetry axis. Here we test between the two ideas. Stimuli consisted of colored Gaussian-blobs arranged either mirror-symmetrically or quasi-randomly. We used four arrangements: (1) 'segregated' - symmetric blobs were of one color, random blobs of the other color(s); (2) 'random-segregated' - as above but with the symmetric color randomly selected on each trial; (3) 'non-segregated' - symmetric blobs were of all colors in equal proportions, as were the random blobs; (4) 'anti-symmetric' - symmetric blobs were of opposite-color across the symmetry axis. We found: (a) near-chance levels for the anti-symmetric condition, suggesting that symmetry perception is sensitive to color-correlations across the symmetry axis; (b) similar performance for random-segregated and non-segregated conditions, giving no support to the idea that mirror-symmetry is color selective; (c) highest performance for the color-segregated condition, but only when the observer knew beforehand the symmetry color, suggesting that symmetry detection benefits from color-based attention. We conclude that mirror-symmetry detection mechanisms, while sensitive to color-correlations across the symmetry axis and subject to the benefits of attention-to-color, are not color selective.

The role of color and attention-to-color in mirror-symmetry perception

PubMed Central

Gheorghiu, Elena; Kingdom, Frederick A. A.; Remkes, Aaron; Li, Hyung-Chul O.; Rainville, Stéphane

2016-01-01

The role of color in the visual perception of mirror-symmetry is controversial. Some reports support the existence of color-selective mirror-symmetry channels, others that mirror-symmetry perception is merely sensitive to color-correlations across the symmetry axis. Here we test between the two ideas. Stimuli consisted of colored Gaussian-blobs arranged either mirror-symmetrically or quasi-randomly. We used four arrangements: (1) ‘segregated’ – symmetric blobs were of one color, random blobs of the other color(s); (2) ‘random-segregated’ – as above but with the symmetric color randomly selected on each trial; (3) ‘non-segregated’ – symmetric blobs were of all colors in equal proportions, as were the random blobs; (4) ‘anti-symmetric’ – symmetric blobs were of opposite-color across the symmetry axis. We found: (a) near-chance levels for the anti-symmetric condition, suggesting that symmetry perception is sensitive to color-correlations across the symmetry axis; (b) similar performance for random-segregated and non-segregated conditions, giving no support to the idea that mirror-symmetry is color selective; (c) highest performance for the color-segregated condition, but only when the observer knew beforehand the symmetry color, suggesting that symmetry detection benefits from color-based attention. We conclude that mirror-symmetry detection mechanisms, while sensitive to color-correlations across the symmetry axis and subject to the benefits of attention-to-color, are not color selective. PMID:27404804

GAFFE: a gaze-attentive fixation finding engine.

PubMed

Rajashekar, U; van der Linde, I; Bovik, A C; Cormack, L K

2008-04-01

The ability to automatically detect visually interesting regions in images has many practical applications, especially in the design of active machine vision and automatic visual surveillance systems. Analysis of the statistics of image features at observers' gaze can provide insights into the mechanisms of fixation selection in humans. Using a foveated analysis framework, we studied the statistics of four low-level local image features: luminance, contrast, and bandpass outputs of both luminance and contrast, and discovered that image patches around human fixations had, on average, higher values of each of these features than image patches selected at random. Contrast-bandpass showed the greatest difference between human and random fixations, followed by luminance-bandpass, RMS contrast, and luminance. Using these measurements, we present a new algorithm that selects image regions as likely candidates for fixation. These regions are shown to correlate well with fixations recorded from human observers.

Ensemble Feature Learning of Genomic Data Using Support Vector Machine

PubMed Central

Anaissi, Ali; Goyal, Madhu; Catchpoole, Daniel R.; Braytee, Ali; Kennedy, Paul J.

2016-01-01

The identification of a subset of genes having the ability to capture the necessary information to distinguish classes of patients is crucial in bioinformatics applications. Ensemble and bagging methods have been shown to work effectively in the process of gene selection and classification. Testament to that is random forest which combines random decision trees with bagging to improve overall feature selection and classification accuracy. Surprisingly, the adoption of these methods in support vector machines has only recently received attention but mostly on classification not gene selection. This paper introduces an ensemble SVM-Recursive Feature Elimination (ESVM-RFE) for gene selection that follows the concepts of ensemble and bagging used in random forest but adopts the backward elimination strategy which is the rationale of RFE algorithm. The rationale behind this is, building ensemble SVM models using randomly drawn bootstrap samples from the training set, will produce different feature rankings which will be subsequently aggregated as one feature ranking. As a result, the decision for elimination of features is based upon the ranking of multiple SVM models instead of choosing one particular model. Moreover, this approach will address the problem of imbalanced datasets by constructing a nearly balanced bootstrap sample. Our experiments show that ESVM-RFE for gene selection substantially increased the classification performance on five microarray datasets compared to state-of-the-art methods. Experiments on the childhood leukaemia dataset show that an average 9% better accuracy is achieved by ESVM-RFE over SVM-RFE, and 5% over random forest based approach. The selected genes by the ESVM-RFE algorithm were further explored with Singular Value Decomposition (SVD) which reveals significant clusters with the selected data. PMID:27304923

Impact of food labelling systems on food choices and eating behaviours: a systematic review and meta-analysis of randomized studies.

PubMed

Cecchini, M; Warin, L

2016-03-01

Food labels are considered a crucial component of strategies tackling unhealthy diets and obesity. This study aims at assessing the effectiveness of food labelling in increasing the selection of healthier products and in reducing calorie intake. In addition, this study compares the relative effectiveness of traffic light schemes, Guideline Daily Amount and other food labelling schemes. A comprehensive set of databases were searched to identify randomized studies. Studies reporting homogeneous outcomes were pooled together and analysed through meta-analyses. Publication bias was evaluated with a funnel plot. Food labelling would increase the amount of people selecting a healthier food product by about 17.95% (confidence interval: +11.24% to +24.66%). Food labelling would also decrease calorie intake/choice by about 3.59% (confidence interval: -8.90% to +1.72%), but results are not statistically significant. Traffic light schemes are marginally more effective in increasing the selection of healthier options. Other food labels and Guideline Daily Amount follow. The available evidence did not allow studying the effects of single labelling schemes on calorie intake/choice. Findings of this study suggest that nutrition labelling may be an effective approach to empowering consumers in choosing healthier products. Interpretive labels, as traffic light labels, may be more effective. © 2015 World Obesity.

Randomization Methods in Emergency Setting Trials: A Descriptive Review

ERIC Educational Resources Information Center

Corbett, Mark Stephen; Moe-Byrne, Thirimon; Oddie, Sam; McGuire, William

2016-01-01

Background: Quasi-randomization might expedite recruitment into trials in emergency care settings but may also introduce selection bias. Methods: We searched the Cochrane Library and other databases for systematic reviews of interventions in emergency medicine or urgent care settings. We assessed selection bias (baseline imbalances) in prognostic…

Middle Level Practices in European International and Department of Defense Schools.

ERIC Educational Resources Information Center

Waggoner, V. Christine; McEwin, C. Kenneth

1993-01-01

Discusses results of a 1989-90 survey of 70 randomly selected international schools and 70 randomly selected Department of Defense Schools in Europe. Programs and practices surveyed included enrollments, grade organization, curriculum and instructional plans, core subjects, grouping patterns, exploratory courses, advisory programs, and scheduling.…

Variable selection with random forest: Balancing stability, performance, and interpretation in ecological and environmental modeling

EPA Science Inventory

Random forest (RF) is popular in ecological and environmental modeling, in part, because of its insensitivity to correlated predictors and resistance to overfitting. Although variable selection has been proposed to improve both performance and interpretation of RF models, it is u...

PRELIMINARY REPORT ON NATIONWIDE STUDY OF DRINKING WATER AND CARDIOVASCULAR DISEASES

EPA Science Inventory

This study was designed to further investigate the association(s) of cardiovascular diseases and drinking water constituents. A sample of 4200 adults were randomly selected from 35 geographic areas to represent the civilian noninstitutionalized population of the contiguous United...

Observational Study Designs for Comparative Effectiveness Research: An Alternative Approach to Close Evidence Gaps in Head-and-Neck Cancer

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

Goulart, Bernardo H.L., E-mail: bhg@uw.edu; University of Washington, Seattle, Washington; Ramsey, Scott D.

Comparative effectiveness research (CER) has emerged as an approach to improve quality of care and patient outcomes while reducing healthcare costs by providing evidence to guide healthcare decisions. Randomized controlled trials (RCTs) have represented the ideal study design to support treatment decisions in head-and-neck (H and N) cancers. In RCTs, formal chance (randomization) determines treatment allocation, which prevents selection bias from distorting the measure of treatment effects. Despite this advantage, only a minority of patients qualify for inclusion in H and N RCTs, which limits the validity of their results to the broader H and N cancer patient population seenmore » in clinical practice. Randomized controlled trials often do not address other knowledge gaps in the management of H and N cancer, including treatment comparisons for rare types of H and N cancers, monitoring of rare or late toxicity events (eg, osteoradionecrosis), or in some instances an RCT is simply not feasible. Observational studies, or studies in which treatment allocation occurs independently of investigators' choice or randomization, may address several of these gaps in knowledge, thereby complementing the role of RCTs. This critical review discusses how observational CER studies complement RCTs in generating the evidence to inform healthcare decisions and improve the quality of care and outcomes of H and N cancer patients. Review topics include a balanced discussion about the strengths and limitations of both RCT and observational CER study designs; a brief description of design and analytic techniques to handle selection bias in observational studies; examples of observational studies that inform current clinical practices and management of H and N cancers; and suggestions for relevant CER questions that could be addressed by an observational study design.« less

Observational study designs for comparative effectiveness research: an alternative approach to close evidence gaps in head-and-neck cancer.

PubMed

Goulart, Bernardo H L; Ramsey, Scott D; Parvathaneni, Upendra

2014-01-01

Comparative effectiveness research (CER) has emerged as an approach to improve quality of care and patient outcomes while reducing healthcare costs by providing evidence to guide healthcare decisions. Randomized controlled trials (RCTs) have represented the ideal study design to support treatment decisions in head-and-neck (H&N) cancers. In RCTs, formal chance (randomization) determines treatment allocation, which prevents selection bias from distorting the measure of treatment effects. Despite this advantage, only a minority of patients qualify for inclusion in H&N RCTs, which limits the validity of their results to the broader H&N cancer patient population seen in clinical practice. Randomized controlled trials often do not address other knowledge gaps in the management of H&N cancer, including treatment comparisons for rare types of H&N cancers, monitoring of rare or late toxicity events (eg, osteoradionecrosis), or in some instances an RCT is simply not feasible. Observational studies, or studies in which treatment allocation occurs independently of investigators' choice or randomization, may address several of these gaps in knowledge, thereby complementing the role of RCTs. This critical review discusses how observational CER studies complement RCTs in generating the evidence to inform healthcare decisions and improve the quality of care and outcomes of H&N cancer patients. Review topics include a balanced discussion about the strengths and limitations of both RCT and observational CER study designs; a brief description of design and analytic techniques to handle selection bias in observational studies; examples of observational studies that inform current clinical practices and management of H&N cancers; and suggestions for relevant CER questions that could be addressed by an observational study design. Copyright © 2014 Elsevier Inc. All rights reserved.

Research Methods in Healthcare Epidemiology and Antimicrobial Stewardship – Quasi-Experimental Designs

PubMed Central

Schweizer, Marin L.; Braun, Barbara I.; Milstone, Aaron M.

2016-01-01

Quasi-experimental studies evaluate the association between an intervention and an outcome using experiments in which the intervention is not randomly assigned. Quasi-experimental studies are often used to evaluate rapid responses to outbreaks or other patient safety problems requiring prompt non-randomized interventions. Quasi-experimental studies can be categorized into three major types: interrupted time series designs, designs with control groups, and designs without control groups. This methods paper highlights key considerations for quasi-experimental studies in healthcare epidemiology and antimicrobial stewardship including study design and analytic approaches to avoid selection bias and other common pitfalls of quasi-experimental studies. PMID:27267457

Assessing different measures of population-level vaccine protection using a case-control study.

PubMed

Ali, Mohammad; You, Young Ae; Kanungo, Suman; Manna, Byomkesh; Deen, Jacqueline L; Lopez, Anna Lena; Wierzba, Thomas F; Bhattacharya, Sujit K; Sur, Dipika; Clemens, John D

2015-11-27

Case-control studies have not been examined for their utility in assessing population-level vaccine protection in individually randomized trials. We used the data of a randomized, placebo-controlled trial of a cholera vaccine to compare the results of case-control analyses with those of cohort analyses. Cases of cholera were selected from the trial population followed for three years following dosing. For each case, we selected 4 age-matched controls who had not developed cholera. For each case and control, GIS was used to calculate vaccine coverage of individuals in a surrounding "virtual" cluster. Specific selection strategies were used to evaluate the vaccine protective effects. 66,900 out of 108,389 individuals received two doses of the assigned regimen. For direct protection among subjects in low vaccine coverage clusters, we observed 78% (95% CI: 47-91%) protection in a cohort analysis and 84% (95% CI: 60-94%) in case-control analysis after adjusting for confounding factors. Using our GIS-based approach, estimated indirect protection was 52% (95% CI: 10-74%) in cohort and 76% (95% CI: 47-89%) in case control analysis. Estimates of total and overall effectiveness were similar for cohort and case-control analyses. The findings show that case-control analyses of individually randomized vaccine trials may be used to evaluate direct as well as population-level vaccine protection. Copyright © 2015. Published by Elsevier Ltd.

Fixation probability in a two-locus intersexual selection model.

PubMed

Durand, Guillermo; Lessard, Sabin

2016-06-01

We study a two-locus model of intersexual selection in a finite haploid population reproducing according to a discrete-time Moran model with a trait locus expressed in males and a preference locus expressed in females. We show that the probability of ultimate fixation of a single mutant allele for a male ornament introduced at random at the trait locus given any initial frequency state at the preference locus is increased by weak intersexual selection and recombination, weak or strong. Moreover, this probability exceeds the initial frequency of the mutant allele even in the case of a costly male ornament if intersexual selection is not too weak. On the other hand, the probability of ultimate fixation of a single mutant allele for a female preference towards a male ornament introduced at random at the preference locus is increased by weak intersexual selection and weak recombination if the female preference is not costly, and is strong enough in the case of a costly male ornament. The analysis relies on an extension of the ancestral recombination-selection graph for samples of haplotypes to take into account events of intersexual selection, while the symbolic calculation of the fixation probabilities is made possible in a reasonable time by an optimizing algorithm. Copyright © 2016 Elsevier Inc. All rights reserved.

Context-specific control and the Stroop negative priming effect.

PubMed

Milliken, Bruce; Thomson, David R; Bleile, Karmen; MacLellan, Ellen; Giammarco, Maria

2012-01-01

The present study highlights the utility of context-specific learning for different probe types in accounting for the commonly observed dependence of negative priming on probe selection. Using a Stroop priming procedure, Experiments 1a and 1b offered a demonstration that Stroop priming effects can differ qualitatively for selection and no-selection probes when probe selection is manipulated between subjects, but not when it is manipulated randomly from trial to trial within subject (see also Moore, 1994). In Experiments 2 and 3, selection and no-selection probes served as two contexts that varied randomly from trial to trial, but for which proportion repeated was manipulated separately. A context-specific proportion repeated effect was observed in Experiment 2, characterized by modest quantitative shifts in the repetition effects as a function of the context-specific proportion repeated manipulation. However, with a longer intertrial interval in Experiment 3, a context-specific proportion repeated manipulation that focused on the no-selection probes changed the repetition effect qualitatively, from negative priming when the proportion repeated was .25 to positive priming when the proportion repeated was .75. The results are discussed with reference to the role of rapid, context-specific learning processes in the integration of prior experiences with current perception and action.

Greedy Gossip With Eavesdropping

NASA Astrophysics Data System (ADS)

Ustebay, Deniz; Oreshkin, Boris N.; Coates, Mark J.; Rabbat, Michael G.

2010-07-01

This paper presents greedy gossip with eavesdropping (GGE), a novel randomized gossip algorithm for distributed computation of the average consensus problem. In gossip algorithms, nodes in the network randomly communicate with their neighbors and exchange information iteratively. The algorithms are simple and decentralized, making them attractive for wireless network applications. In general, gossip algorithms are robust to unreliable wireless conditions and time varying network topologies. In this paper we introduce GGE and demonstrate that greedy updates lead to rapid convergence. We do not require nodes to have any location information. Instead, greedy updates are made possible by exploiting the broadcast nature of wireless communications. During the operation of GGE, when a node decides to gossip, instead of choosing one of its neighbors at random, it makes a greedy selection, choosing the node which has the value most different from its own. In order to make this selection, nodes need to know their neighbors' values. Therefore, we assume that all transmissions are wireless broadcasts and nodes keep track of their neighbors' values by eavesdropping on their communications. We show that the convergence of GGE is guaranteed for connected network topologies. We also study the rates of convergence and illustrate, through theoretical bounds and numerical simulations, that GGE consistently outperforms randomized gossip and performs comparably to geographic gossip on moderate-sized random geometric graph topologies.

Adaptive Electronic Camouflage Using Texture Synthesis

DTIC Science & Technology

2012-04-01

algorithm begins by computing the GLCMs, GIN and GOUT , of the input image (e.g., image of local environment) and output image (randomly generated...respectively. The algorithm randomly selects a pixel from the output image and cycles its gray-level through all values. For each value, GOUT is updated...The value of the selected pixel is permanently changed to the gray-level value that minimizes the error between GIN and GOUT . Without selecting a

Caries status in 16 year-olds with varying exposure to water fluoridation in Ireland.

PubMed

Mullen, J; McGaffin, J; Farvardin, N; Brightman, S; Haire, C; Freeman, R

2012-12-01

Most of the Republic of Ireland's public water supplies have been fluoridated since the mid-1960s while Northern Ireland has never been fluoridated, apart from some small short-lived schemes in east Ulster. This study examines dental caries status in 16 year-olds in a part of Ireland straddling fluoridated and non-fluoridated water supply areas and compares two methods of assessing the effectiveness of water fluoridation. The cross-sectional survey tested differences in caries status by two methods: 1, Estimated Fluoridation Status as used previously in national and regional studies in the Republic and in the All-Island study of 2002; 2, Percentage Lifetime Exposure, a modification of a system described by Slade in 1995 and used in Australian caries research. Adolescents were selected for the study by a two-part random sampling process. Firstly, schools were selected in each area by creating three tiers based on school size, and selecting schools randomly from each tier. Then random sampling of 16-year-olds from these schools, based on a pre-set sampling fraction for each tier of schools. With both systems of measurement, significantly lower caries levels were found in those children with the greatest exposure to fluoridated water when compared to those with the least exposure. The survey provides further evidence of the effectiveness in reducing dental caries experience up to 16 years of age. The extra intricacies involved in using the Percentage Lifetime Exposure method did not provide much more information when compared to the simpler Estimated Fluoridation Status method.

Effectiveness of a new health care organization model in primary care for chronic cardiovascular disease patients based on a multifactorial intervention: the PROPRESE randomized controlled trial

PubMed Central

2013-01-01

Background To evaluate the effectiveness of a new multifactorial intervention to improve health care for chronic ischemic heart disease patients in primary care. The strategy has two components: a) organizational for the patient/professional relationship and b) training for professionals. Methods/design Experimental study. Randomized clinical trial. Follow-up period: one year. Study setting: primary care, multicenter (15 health centers). For the intervention group 15 health centers are selected from those participating in ESCARVAL study. Once the center agreed to participate patients are randomly selected from the total amount of patients with ischemic heart disease registered in the electronic health records. For the control group a random sample of patients with ischemic heart disease is selected from all 72 health centers electronic records. Intervention components: a) Organizational intervention on the patient/professional relationship. Centered on the Chronic Care Model, the Stanford Expert Patient Program and the Kaiser Permanente model: Teamwork, informed and active patient, decision making shared with the patient, recommendations based on clinical guidelines, single electronic medical history per patient that allows the use of indicators for risk monitoring and stratification. b) Formative strategy for professionals: 4 face-to-face training workshops (one every 3 months), monthly update clinical sessions, online tutorial by a cardiologist, availability through the intranet of the action protocol and related documents. Measurements: Blood pressure, blood glucose, HbA1c, lipid profile and smoking. Frequent health care visits. Number of hospitalizations related to vascular disease. Therapeutic compliance. Drug use. Discussion This study aims to evaluate the efficacy of a multifactorial intervention strategy involving patients with ischemic heart disease for the improvement of the degree of control of the cardiovascular risk factors and of the quality of life, number of visits, and number of hospitalizations. Trial registration NCT01826929 PMID:23915267

Study Design and Rationale for a Randomized, Placebo-Controlled, Double-Blind Study to Assess the Efficacy and Safety of Selumetinib in Combination With Docetaxel as Second-Line Treatment in Patients With KRAS-Mutant Advanced Non-Small Cell Lung Cancer (SELECT-1).

PubMed

Jänne, Pasi A; Mann, Helen; Ghiorghiu, Dana

2016-03-01

Oncogenic KRAS mutations represent the largest genomically defined subset of lung cancer, and are associated with activation of the RAS/RAF/MEK/ERK pathway. There are currently no therapies specifically approved for patients with KRAS-mutant (KRASm) non-small-cell lung cancer (NSCLC), and these patients derive less clinical benefit from chemotherapy than the overall NSCLC population. In a recent phase II study, selumetinib (AZD6244, ARRY-142886), an oral, potent and selective, allosteric MEK1/2 inhibitor with a short half-life, combined with docetaxel, improved clinical outcome as second-line treatment for patients with KRASm NSCLC. This combination will be further evaluated in the phase III SELECT-1 study. SELECT-1 (NCT01933932) is a randomized, double-blind, placebo-controlled phase III study assessing the efficacy and safety of selumetinib plus docetaxel in patients with KRASm locally advanced or metastatic NSCLC, eligible for second-line treatment. The primary endpoint is progression-free survival (PFS); secondary endpoints include overall survival, objective response rate, duration of response, and safety and tolerability. Approximately 634 patients will be randomized 1:1 to receive selumetinib (75 mg twice daily on a continuous oral administration schedule) in combination with docetaxel (75 mg/m(2), intravenously on day 1 of every 21-day cycle) or placebo in combination with docetaxel (same schedule), until objective disease progression. Patients may continue to receive treatment after objective disease progression if deemed appropriate by the investigator. If the primary endpoint of PFS is met, selumetinib plus docetaxel would be the first targeted treatment for patients with KRASm advanced NSCLC who are eligible for second-line treatment. Copyright © 2016 Elsevier Inc. All rights reserved.

PyCCF: Python Cross Correlation Function for reverberation mapping studies

NASA Astrophysics Data System (ADS)

Sun, Mouyuan; Grier, C. J.; Peterson, B. M.

2018-05-01

PyCCF emulates a Fortran program written by B. Peterson for use with reverberation mapping. The code cross correlates two light curves that are unevenly sampled using linear interpolation and measures the peak and centroid of the cross-correlation function. In addition, it is possible to run Monto Carlo iterations using flux randomization and random subset selection (RSS) to produce cross-correlation centroid distributions to estimate the uncertainties in the cross correlation results.

Results from six generations of selection for intramuscular fat in Duroc swine using real-time ultrasound. I. Direct and correlated phenotypic responses to selection.

PubMed

Schwab, C R; Baas, T J; Stalder, K J; Nettleton, D

2009-09-01

A study was conducted to evaluate the efficacy of selection for intramuscular fat (IMF) in a population of purebred Duroc swine using real-time ultrasound. Forty gilts were purchased from US breeders and randomly mated for 2 generations to boars available in regional boar studs, resulting in a base population of 56 litters. Littermate pairs of gilts from this population were randomly assigned to a select line (SL) or control line (CL) and mated to the same sire to establish genetic ties between lines. At an average BW of 114 kg, a minimum of 4 longitudinal ultrasound images were collected 7 cm off-midline across the 10th to 13th ribs of all pigs for the prediction of IMF (UIMF). At least 1 barrow or gilt was slaughtered from each litter, and carcass data were collected. A sample of the LM from the 10th to 11th rib interface was analyzed for carcass IMF (CIMF). Breeding values for IMF were estimated by fitting a 2-trait (UIMF and CIMF) animal model in MATVEC. In the SL, selection in each subsequent generation was based on EBV for IMF with the top 10 boars and top 75 gilts used to produce the next generation. One boar from each sire family and 50 to 60 gilts representing all sire families were randomly selected to maintain the CL. Through 6 generations of selection, an 88% improvement in IMF has been realized (4.53% in SL vs. 2.41% in CL). Results of this study revealed no significant correlated responses in measures of growth performance. However, 6 generations of selection for IMF have yielded correlated effects of decreased loin muscle area and increased backfat. Additionally, the SL obtained more desirable objective measures of tenderness and sensory evaluations of flavor and off-flavor. Meat quality characteristics of pH, water holding capacity, and percent cooking loss were not significantly affected by selection for IMF. Selection for IMF using real-time ultrasound is effective but may be associated with genetic ramifications for carcass composition traits. Intramuscular fat may be used in purebred Duroc swine breeding programs as an indicator trait for sensory traits that influence consumer acceptance; however, rapid improvement should not be expected when simultaneous improvement in other trait categories is also pursued.

Response rate differences between web and alternative data collection methods for public health research: a systematic review of the literature.

PubMed

Blumenberg, Cauane; Barros, Aluísio J D

2018-07-01

To systematically review the literature and compare response rates (RRs) of web surveys to alternative data collection methods in the context of epidemiologic and public health studies. We reviewed the literature using PubMed, LILACS, SciELO, WebSM, and Google Scholar databases. We selected epidemiologic and public health studies that considered the general population and used two parallel data collection methods, being one web-based. RR differences were analyzed using two-sample test of proportions, and pooled using random effects. We investigated agreement using Bland-and-Altman, and correlation using Pearson's coefficient. We selected 19 studies (nine randomized trials). The RR of the web-based data collection was 12.9 percentage points (p.p.) lower (95% CI = - 19.0, - 6.8) than the alternative methods, and 15.7 p.p. lower (95% CI = - 24.2, - 7.3) considering only randomized trials. Monetary incentives did not reduce the RR differences. A strong positive correlation (r = 0.83) between the RRs was observed. Web-based data collection present lower RRs compared to alternative methods. However, it is not recommended to interpret this as a meta-analytical evidence due to the high heterogeneity of the studies.

Construction and identification of a D-Vine model applied to the probability distribution of modal parameters in structural dynamics

NASA Astrophysics Data System (ADS)

Dubreuil, S.; Salaün, M.; Rodriguez, E.; Petitjean, F.

2018-01-01

This study investigates the construction and identification of the probability distribution of random modal parameters (natural frequencies and effective parameters) in structural dynamics. As these parameters present various types of dependence structures, the retained approach is based on pair copula construction (PCC). A literature review leads us to choose a D-Vine model for the construction of modal parameters probability distributions. Identification of this model is based on likelihood maximization which makes it sensitive to the dimension of the distribution, namely the number of considered modes in our context. To this respect, a mode selection preprocessing step is proposed. It allows the selection of the relevant random modes for a given transfer function. The second point, addressed in this study, concerns the choice of the D-Vine model. Indeed, D-Vine model is not uniquely defined. Two strategies are proposed and compared. The first one is based on the context of the study whereas the second one is purely based on statistical considerations. Finally, the proposed approaches are numerically studied and compared with respect to their capabilities, first in the identification of the probability distribution of random modal parameters and second in the estimation of the 99 % quantiles of some transfer functions.

Academic Self-Efficacy Perceptions of Teacher Candidates

ERIC Educational Resources Information Center

Yesilyurt, Etem

2013-01-01

This study aims determining academic self-efficacy perception of teacher candidates. It is survey model. Population of the study consists of teacher candidates in 2010-2011 academic years at Ahmet Kelesoglu Education Faculty of Education Formation of Selcuk University. A simple random sample was selected as sampling method and the study was…

Determining the Anxiety Sensitivity Bases of Anxiety: A Study with Undergraduate Students

ERIC Educational Resources Information Center

Erozkan, Atilgan

2017-01-01

This study aims to examine the relationships between subdimensions of anxiety sensitivity and anxiety. The participants in the study were 841 undergraduate students (411 females; 430 males) randomly selected from three different faculties--Faculties of Technical Education, Education, and Sport Sciences--at Mugla Sitki Kocman University. Data…

Correlates of School Stress.

ERIC Educational Resources Information Center

Matthews, Doris B.

As part of a continuing series of research studies on stress in schools, this study examined the construct validity of peripheral temperature at the fingertips as a measure of school stress. Measurements were made in classes selected at random from 11 volunteer schools in South Carolina. Three types of correlational studies were undertaken: (1)…

Stressful life events and cancer risk

PubMed Central

Bergelt, C; Prescott, E; Grønbæk, M; Koch, U; Johansen, C

2006-01-01

In a prospective cohort study in Denmark of 8736 randomly selected people, no evidence was found among 1011 subjects who developed cancer that self-reported stressful major life events had increased their risk for cancer. PMID:17106440

Non-manipulation quantitative designs.

PubMed

Rumrill, Phillip D

2004-01-01

The article describes non-manipulation quantitative designs of two types, correlational and causal comparative studies. Both of these designs are characterized by the absence of random assignment of research participants to conditions or groups and non-manipulation of the independent variable. Without random selection or manipulation of the independent variable, no attempt is made to draw causal inferences regarding relationships between independent and dependent variables. Nonetheless, non-manipulation studies play an important role in rehabilitation research, as described in this article. Examples from the contemporary rehabilitation literature are included. Copyright 2004 IOS Press

Tissue segmentation of computed tomography images using a Random Forest algorithm: a feasibility study

NASA Astrophysics Data System (ADS)

Polan, Daniel F.; Brady, Samuel L.; Kaufman, Robert A.

2016-09-01

There is a need for robust, fully automated whole body organ segmentation for diagnostic CT. This study investigates and optimizes a Random Forest algorithm for automated organ segmentation; explores the limitations of a Random Forest algorithm applied to the CT environment; and demonstrates segmentation accuracy in a feasibility study of pediatric and adult patients. To the best of our knowledge, this is the first study to investigate a trainable Weka segmentation (TWS) implementation using Random Forest machine-learning as a means to develop a fully automated tissue segmentation tool developed specifically for pediatric and adult examinations in a diagnostic CT environment. Current innovation in computed tomography (CT) is focused on radiomics, patient-specific radiation dose calculation, and image quality improvement using iterative reconstruction, all of which require specific knowledge of tissue and organ systems within a CT image. The purpose of this study was to develop a fully automated Random Forest classifier algorithm for segmentation of neck-chest-abdomen-pelvis CT examinations based on pediatric and adult CT protocols. Seven materials were classified: background, lung/internal air or gas, fat, muscle, solid organ parenchyma, blood/contrast enhanced fluid, and bone tissue using Matlab and the TWS plugin of FIJI. The following classifier feature filters of TWS were investigated: minimum, maximum, mean, and variance evaluated over a voxel radius of 2 n , (n from 0 to 4), along with noise reduction and edge preserving filters: Gaussian, bilateral, Kuwahara, and anisotropic diffusion. The Random Forest algorithm used 200 trees with 2 features randomly selected per node. The optimized auto-segmentation algorithm resulted in 16 image features including features derived from maximum, mean, variance Gaussian and Kuwahara filters. Dice similarity coefficient (DSC) calculations between manually segmented and Random Forest algorithm segmented images from 21 patient image sections, were analyzed. The automated algorithm produced segmentation of seven material classes with a median DSC of 0.86  ±  0.03 for pediatric patient protocols, and 0.85  ±  0.04 for adult patient protocols. Additionally, 100 randomly selected patient examinations were segmented and analyzed, and a mean sensitivity of 0.91 (range: 0.82-0.98), specificity of 0.89 (range: 0.70-0.98), and accuracy of 0.90 (range: 0.76-0.98) were demonstrated. In this study, we demonstrate that this fully automated segmentation tool was able to produce fast and accurate segmentation of the neck and trunk of the body over a wide range of patient habitus and scan parameters.

What affects response rates in primary healthcare-based programmes? An analysis of individual and unit-related factors associated with increased odds of non-response based on HCV screening in the general population in Poland

PubMed Central

Parda, Natalia; Stępień, Małgorzata; Zakrzewska, Karolina; Madaliński, Kazimierz; Kołakowska, Agnieszka; Godzik, Paulina; Rosińska, Magdalena

2016-01-01

Objectives Response rate in public health programmes may be a limiting factor. It is important to first consider their delivery and acceptability for the target. This study aimed at determining individual and unit-related factors associated with increased odds of non-response based on hepatitis C virus screening in primary healthcare. Design Primary healthcare units (PHCUs) were extracted from the Register of Health Care Centres. Each of the PHCUs was to enrol adult patients selected on a random basis. Data on the recruitment of PHCUs and patients were analysed. Multilevel modelling was applied to investigate individual and unit-related factors associated with non-response. Multilevel logistic model was developed with fixed effects and only a random intercept for the unit. Preliminary analysis included a random effect for unit and each of the individual or PHCU covariates separately. For each of the PHCU covariates, we applied a two-level model with individual covariates, unit random effect and a single fixed effect of this unit covariate. Setting This study was conducted in primary care units in selected provinces in Poland. Participants A total of 242 PHCUs and 24 480 adults were invited. Of them, 44 PHCUs and 20 939 patients agreed to participate. Both PHCUs and patients were randomly selected. Results Data on 44 PHCUs and 24 480 patients were analysed. PHCU-level factors and recruitment strategies were important predictors of non-response. Unit random effect was significant in all models. Larger and private units reported higher non-response rates, while for those with a history of running public health programmes the odds of non-response was lower. Proactive recruitment, more working hours devoted to the project and patient resulted in higher acceptance of the project. Higher number of personnel had no such effect. Conclusions Prior to the implementation of public health programme, several factors that could hinder its execution should be addressed. PMID:27927665

What affects response rates in primary healthcare-based programmes? An analysis of individual and unit-related factors associated with increased odds of non-response based on HCV screening in the general population in Poland.

PubMed

Parda, Natalia; Stępień, Małgorzata; Zakrzewska, Karolina; Madaliński, Kazimierz; Kołakowska, Agnieszka; Godzik, Paulina; Rosińska, Magdalena

2016-12-07

Response rate in public health programmes may be a limiting factor. It is important to first consider their delivery and acceptability for the target. This study aimed at determining individual and unit-related factors associated with increased odds of non-response based on hepatitis C virus screening in primary healthcare. Primary healthcare units (PHCUs) were extracted from the Register of Health Care Centres. Each of the PHCUs was to enrol adult patients selected on a random basis. Data on the recruitment of PHCUs and patients were analysed. Multilevel modelling was applied to investigate individual and unit-related factors associated with non-response. Multilevel logistic model was developed with fixed effects and only a random intercept for the unit. Preliminary analysis included a random effect for unit and each of the individual or PHCU covariates separately. For each of the PHCU covariates, we applied a two-level model with individual covariates, unit random effect and a single fixed effect of this unit covariate. This study was conducted in primary care units in selected provinces in Poland. A total of 242 PHCUs and 24 480 adults were invited. Of them, 44 PHCUs and 20 939 patients agreed to participate. Both PHCUs and patients were randomly selected. Data on 44 PHCUs and 24 480 patients were analysed. PHCU-level factors and recruitment strategies were important predictors of non-response. Unit random effect was significant in all models. Larger and private units reported higher non-response rates, while for those with a history of running public health programmes the odds of non-response was lower. Proactive recruitment, more working hours devoted to the project and patient resulted in higher acceptance of the project. Higher number of personnel had no such effect. Prior to the implementation of public health programme, several factors that could hinder its execution should be addressed. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

RARtool: A MATLAB Software Package for Designing Response-Adaptive Randomized Clinical Trials with Time-to-Event Outcomes.

PubMed

Ryeznik, Yevgen; Sverdlov, Oleksandr; Wong, Weng Kee

2015-08-01

Response-adaptive randomization designs are becoming increasingly popular in clinical trial practice. In this paper, we present RARtool , a user interface software developed in MATLAB for designing response-adaptive randomized comparative clinical trials with censored time-to-event outcomes. The RARtool software can compute different types of optimal treatment allocation designs, and it can simulate response-adaptive randomization procedures targeting selected optimal allocations. Through simulations, an investigator can assess design characteristics under a variety of experimental scenarios and select the best procedure for practical implementation. We illustrate the utility of our RARtool software by redesigning a survival trial from the literature.

Interacting particle systems on graphs

NASA Astrophysics Data System (ADS)

Sood, Vishal

In this dissertation, the dynamics of socially or biologically interacting populations are investigated. The individual members of the population are treated as particles that interact via links on a social or biological network represented as a graph. The effect of the structure of the graph on the properties of the interacting particle system is studied using statistical physics techniques. In the first chapter, the central concepts of graph theory and social and biological networks are presented. Next, interacting particle systems that are drawn from physics, mathematics and biology are discussed in the second chapter. In the third chapter, the random walk on a graph is studied. The mean time for a random walk to traverse between two arbitrary sites of a random graph is evaluated. Using an effective medium approximation it is found that the mean first-passage time between pairs of sites, as well as all moments of this first-passage time, are insensitive to the density of links in the graph. The inverse of the mean-first passage time varies non-monotonically with the density of links near the percolation transition of the random graph. Much of the behavior can be understood by simple heuristic arguments. Evolutionary dynamics, by which mutants overspread an otherwise uniform population on heterogeneous graphs, are studied in the fourth chapter. Such a process underlies' epidemic propagation, emergence of fads, social cooperation or invasion of an ecological niche by a new species. The first part of this chapter is devoted to neutral dynamics, in which the mutant genotype does not have a selective advantage over the resident genotype. The time to extinction of one of the two genotypes is derived. In the second part of this chapter, selective advantage or fitness is introduced such that the mutant genotype has a higher birth rate or a lower death rate. This selective advantage leads to a dynamical competition in which selection dominates for large populations, while for small populations the dynamics are similar to the neutral case. The likelihood for the fitter mutants to drive the resident genotype to extinction is calculated.

Rib fractures in trauma patients: does operative fixation improve outcome?

PubMed

Majak, Peter; Næss, Pål A

2016-12-01

Renewed interest in surgical fixation of rib fractures has emerged. However, conservative treatment is still preferred at most surgical departments. We wanted to evaluate whether operative treatment of rib fractures may benefit severely injured patients. Several studies report a reduction in mechanical ventilation time, ICU length of stay (LOS), hospital LOS, pneumonia, need for tracheostomy, pain and costs in operatively treated patients with multiple rib fractures compared with patients treated nonoperatively. Although patient selection and timing of the operation seem crucial for successful outcome, no consensus exists. Mortality reduction has only been shown in a few studies. Most studies are retrospective cohort and case-control studies. Only four randomized control trials exist. Conservative treatment, consisting of respiratory assistance and pain control, is still the treatment of choice in the vast majority of patients with multiple rib fractures. In selected patients, operative fixation of fractured ribs within 72 h postinjury may lead to better outcome. More randomized control trials are needed to further determine who benefits from surgical fixation of rib fractures.

78 FR 57033 - United States Standards for Condition of Food Containers

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-17

... containers during production. Stationary lot sampling is the process of randomly selecting sample units from.... * * * * * Stationary lot sampling. The process of randomly selecting sample units from a lot whose production has been... less than \\1/16\\-inch Stringy seal (excessive plastic threads showing at edge of seal 222 area...

Access to Higher Education by the Luck of the Draw

ERIC Educational Resources Information Center

Stone, Peter

2013-01-01

Random selection is a fair way to break ties between applicants of equal merit seeking admission to institutions of higher education (with "merit" defined here in terms of the intrinsic contribution higher education would make to the applicant's life). Opponents of random selection commonly argue that differences in strength between…

An Evaluation of Information Criteria Use for Correct Cross-Classified Random Effects Model Selection

ERIC Educational Resources Information Center

Beretvas, S. Natasha; Murphy, Daniel L.

2013-01-01

The authors assessed correct model identification rates of Akaike's information criterion (AIC), corrected criterion (AICC), consistent AIC (CAIC), Hannon and Quinn's information criterion (HQIC), and Bayesian information criterion (BIC) for selecting among cross-classified random effects models. Performance of default values for the 5…

1977 Survey of the American Professoriate. Technical Report.

ERIC Educational Resources Information Center

Ladd, Everett Carll, Jr.; And Others

The development and data validation of the 1977 Ladd-Lipset national survey of the American professoriate are described. The respondents were selected from a random sample of colleges and universities and from a random sample of individual faculty members from the universities. The 158 institutions in the 1977 survey were selected from 2,406…

Evaluation of an Intervention to Foster Time Perspective and Career Decidedness in a Group of Italian Adolescents

ERIC Educational Resources Information Center

Ferrari, Lea; Nota, Laura; Soresi, Salvatore

2012-01-01

A structured 10-didactic unit intervention was devised to foster adolescents' time perspective and career decidedness. The study was conducted with 50 adolescents who were selected from a group of 624; 25 of the participants were randomly assigned to the control group and 25 were assigned to the experimental group. They were selected according to…

Advanced Cancer Detection Center

DTIC Science & Technology

2007-10-01

therapy in children: A Phase II randomized double blinded cross-over study (HLMCC 0708) • Risperidone for the Treatment of Cerebellar Mutism Syndrome...each question, the participant selects the answer by using the left and right arrow keys and then pressing the Choose button. The next question is...transformed to a quantitative scale measure for transmission. Numeric responses can be entered directly or can be selected from a list of

The Differential Effects of Selected Programs on the Performance, Degree of Satisfaction and Retention of Community College Women Students. Final Report.

ERIC Educational Resources Information Center

Gillie, Angelo C.

This study, by examining how female post-secondary students view themselves within their college environment, attempts to determine how education can become more relevant for these women. Random samples of freshmen women students from four community colleges were selected according to the type of program in which they were enrolled--human service,…

THE SOCIAL PROBLEMS OF MIGRANT FARM LABORERS--EFFECT OF MIGRANT FARM LABOR ON THE EDUCATION OF CHILDREN.

ERIC Educational Resources Information Center

BROOKS, MELVIN S.; HILGENDORF, ROBERT L.

MIGRANT LABORERS WHO PICKED STRAWBERRIES IN SOUTHERN ILLINOIS IN THE SPRING OF 1958 WERE SURVEYED. THIS PARTICULAR SAMPLE WAS SELECTED FOR STUDY BECAUSE FAR MORE CHILDREN ARE INVOLVED IN THE HARVEST OF STRAWBERRIES THAN IN ANY OTHER FARM TASK OF THE AREA. MIGRANTS WHO WERE INTERVIEWED WERE SELECTED BY SYSTEMATIC RANDOM SAMPLING--A PROCEDURE THAT…

Health of women: associations among life events, social support, and personality for selected patient groups.

PubMed

Norlander, T; Dahlin, A; Archer, T

2000-02-01

This study examined the effects of life events, social support, personality traits, and siblings' birth-order on the health of women. 199 middle-class participants were included. 95 women, randomly assigned from four different patient groups, were compared with a control group of 96 randomly selected women without any special health problems. They completed a questionnaire which included questions regarding family background, health, different life events, social support, and signs of disease and a projective test, the Sivik Psychosomatism Test. Analysis indicated that report of negative life events was associated with more physical symptoms than positive life events and that the patient groups reported more negative life events and less social support than the control group.

Controllability of social networks and the strategic use of random information.

PubMed

Cremonini, Marco; Casamassima, Francesca

2017-01-01

This work is aimed at studying realistic social control strategies for social networks based on the introduction of random information into the state of selected driver agents. Deliberately exposing selected agents to random information is a technique already experimented in recommender systems or search engines, and represents one of the few options for influencing the behavior of a social context that could be accepted as ethical, could be fully disclosed to members, and does not involve the use of force or of deception. Our research is based on a model of knowledge diffusion applied to a time-varying adaptive network and considers two well-known strategies for influencing social contexts: One is the selection of few influencers for manipulating their actions in order to drive the whole network to a certain behavior; the other, instead, drives the network behavior acting on the state of a large subset of ordinary, scarcely influencing users. The two approaches have been studied in terms of network and diffusion effects. The network effect is analyzed through the changes induced on network average degree and clustering coefficient, while the diffusion effect is based on two ad hoc metrics which are defined to measure the degree of knowledge diffusion and skill level, as well as the polarization of agent interests. The results, obtained through simulations on synthetic networks, show a rich dynamics and strong effects on the communication structure and on the distribution of knowledge and skills. These findings support our hypothesis that the strategic use of random information could represent a realistic approach to social network controllability, and that with both strategies, in principle, the control effect could be remarkable.

Overlapping meta-analyses on the same topic: survey of published studies.

PubMed

Siontis, Konstantinos C; Hernandez-Boussard, Tina; Ioannidis, John P A

2013-07-19

To assess how common it is to have multiple overlapping meta-analyses of randomized trials published on the same topic. Survey of published meta-analyses. PubMed. Meta-analyses published in 2010 were identified, and 5% of them were randomly selected. We further selected those that included randomized trials and examined effectiveness of any medical intervention. For eligible meta-analyses, we searched for other meta-analyses on the same topic (covering the same comparisons, indications/settings, and outcomes or overlapping subsets of them) published until February 2013. Of 73 eligible meta-analyses published in 2010, 49 (67%) had at least one other overlapping meta-analysis (median two meta-analyses per topic, interquartile range 1-4, maximum 13). In 17 topics at least one author was involved in at least two of the overlapping meta-analyses. No characteristics of the index meta-analyses were associated with the potential for overlapping meta-analyses. Among pairs of overlapping meta-analyses in 20 randomly selected topics, 13 of the more recent meta-analyses did not include any additional outcomes. In three of the four topics with eight or more published meta-analyses, many meta-analyses examined only a subset of the eligible interventions or indications/settings covered by the index meta-analysis. Conversely, for statins in the prevention of atrial fibrillation after cardiac surgery, 11 meta-analyses were published with similar eligibility criteria for interventions and setting: there was still variability on which studies were included, but the results were always similar or even identical across meta-analyses. While some independent replication of meta-analyses by different teams is possibly useful, the overall picture suggests that there is a waste of efforts with many topics covered by multiple overlapping meta-analyses.

Attitudes towards smoking restrictions and tobacco advertisement bans in Georgia.

PubMed

Bakhturidze, George D; Mittelmark, Maurice B; Aarø, Leif E; Peikrishvili, Nana T

2013-11-25

This study aims to provide data on a public level of support for restricting smoking in public places and banning tobacco advertisements. A nationally representative multistage sampling design, with sampling strata defined by region (sampling quotas proportional to size) and substrata defined by urban/rural and mountainous/lowland settlement, within which census enumeration districts were randomly sampled, within which households were randomly sampled, within which a randomly selected respondent was interviewed. The country of Georgia, population 4.7 million, located in the Caucasus region of Eurasia. One household member aged between 13 and 70 was selected as interviewee. In households with more than one age-eligible person, selection was carried out at random. Of 1588 persons selected, 14 refused to participate and interviews were conducted with 915 women and 659 men. Respondents were interviewed about their level of agreement with eight possible smoking restrictions/bans, used to calculate a single dichotomous (agree/do not agree) opinion indicator. The level of agreement with restrictions was analysed in bivariate and multivariate analyses by age, gender, education, income and tobacco use status. Overall, 84.9% of respondents indicated support for smoking restrictions and tobacco advertisement bans. In all demographic segments, including tobacco users, the majority of respondents indicated agreement with restrictions, ranging from a low of 51% in the 13-25 age group to a high of 98% in the 56-70 age group. Logistic regression with all demographic variables entered showed that agreement with restrictions was higher with age, and was significantly higher among never smokers as compared to daily smokers. Georgian public opinion is normatively supportive of more stringent tobacco-control measures in the form of smoking restrictions and tobacco advertisement bans.

Influence of olfactory and visual cover on nest site selection and nest success for grassland-nesting birds.

PubMed

Fogarty, Dillon T; Elmore, R Dwayne; Fuhlendorf, Samuel D; Loss, Scott R

2017-08-01

Habitat selection by animals is influenced by and mitigates the effects of predation and environmental extremes. For birds, nest site selection is crucial to offspring production because nests are exposed to extreme weather and predation pressure. Predators that forage using olfaction often dominate nest predator communities; therefore, factors that influence olfactory detection (e.g., airflow and weather variables, including turbulence and moisture) should influence nest site selection and survival. However, few studies have assessed the importance of olfactory cover for habitat selection and survival. We assessed whether ground-nesting birds select nest sites based on visual and/or olfactory cover. Additionally, we assessed the importance of visual cover and airflow and weather variables associated with olfactory cover in influencing nest survival. In managed grasslands in Oklahoma, USA, we monitored nests of Northern Bobwhite ( Colinus virginianus ), Eastern Meadowlark ( Sturnella magna ), and Grasshopper Sparrow ( Ammodramus savannarum ) during 2015 and 2016. To assess nest site selection, we compared cover variables between nests and random points. To assess factors influencing nest survival, we used visual cover and olfactory-related measurements (i.e., airflow and weather variables) to model daily nest survival. For nest site selection, nest sites had greater overhead visual cover than random points, but no other significant differences were found. Weather variables hypothesized to influence olfactory detection, specifically precipitation and relative humidity, were the best predictors of and were positively related to daily nest survival. Selection for overhead cover likely contributed to mitigation of thermal extremes and possibly reduced detectability of nests. For daily nest survival, we hypothesize that major nest predators focused on prey other than the monitored species' nests during high moisture conditions, thus increasing nest survival on these days. Our study highlights how mechanistic approaches to studying cover informs which dimensions are perceived and selected by animals and which dimensions confer fitness-related benefits.

Not accounting for interindividual variability can mask habitat selection patterns: a case study on black bears.

PubMed

Lesmerises, Rémi; St-Laurent, Martin-Hugues

2017-11-01

Habitat selection studies conducted at the population scale commonly aim to describe general patterns that could improve our understanding of the limiting factors in species-habitat relationships. Researchers often consider interindividual variation in selection patterns to control for its effects and avoid pseudoreplication by using mixed-effect models that include individuals as random factors. Here, we highlight common pitfalls and possible misinterpretations of this strategy by describing habitat selection of 21 black bears Ursus americanus. We used Bayesian mixed-effect models and compared results obtained when using random intercept (i.e., population level) versus calculating individual coefficients for each independent variable (i.e., individual level). We then related interindividual variability to individual characteristics (i.e., age, sex, reproductive status, body condition) in a multivariate analysis. The assumption of comparable behavior among individuals was verified only in 40% of the cases in our seasonal best models. Indeed, we found strong and opposite responses among sampled bears and individual coefficients were linked to individual characteristics. For some covariates, contrasted responses canceled each other out at the population level. In other cases, interindividual variability was concealed by the composition of our sample, with the majority of the bears (e.g., old individuals and bears in good physical condition) driving the population response (e.g., selection of young forest cuts). Our results stress the need to consider interindividual variability to avoid misinterpretation and uninformative results, especially for a flexible and opportunistic species. This study helps to identify some ecological drivers of interindividual variability in bear habitat selection patterns.

Foundational errors in the Neutral and Nearly-Neutral theories of evolution in relation to the Synthetic Theory: is a new evolutionary paradigm necessary?

PubMed

Valenzuela, Carlos Y

2013-01-01

The Neutral Theory of Evolution (NTE) proposes mutation and random genetic drift as the most important evolutionary factors. The most conspicuous feature of evolution is the genomic stability during paleontological eras and lack of variation among taxa; 98% or more of nucleotide sites are monomorphic within a species. NTE explains this homology by random fixation of neutral bases and negative selection (purifying selection) that does not contribute either to evolution or polymorphisms. Purifying selection is insufficient to account for this evolutionary feature and the Nearly-Neutral Theory of Evolution (N-NTE) included negative selection with coefficients as low as mutation rate. These NTE and N-NTE propositions are thermodynamically (tendency to random distributions, second law), biotically (recurrent mutation), logically and mathematically (resilient equilibria instead of fixation by drift) untenable. Recurrent forward and backward mutation and random fluctuations of base frequencies alone in a site make life organization and fixations impossible. Drift is not a directional evolutionary factor, but a directional tendency of matter-energy processes (second law) which threatens the biotic organization. Drift cannot drive evolution. In a site, the mutation rates among bases and selection coefficients determine the resilient equilibrium frequency of bases that genetic drift cannot change. The expected neutral random interaction among nucleotides is zero; however, huge interactions and periodicities were found between bases of dinucleotides separated by 1, 2... and more than 1,000 sites. Every base is co-adapted with the whole genome. Neutralists found that neutral evolution is independent of population size (N); thus neutral evolution should be independent of drift, because drift effect is dependent upon N. Also, chromosome size and shape as well as protein size are far from random.

The estimation of selection coefficients in Afrikaners: Huntington disease, porphyria variegata, and lipoid proteinosis.

PubMed Central

Stine, O C; Smith, K D

1990-01-01

The effects of mutation, migration, random drift, and selection on the change in frequency of the alleles associated with Huntington disease, porphyria variegata, and lipoid proteinosis have been assessed in the Afrikaner population of South Africa. Although admixture cannot be completely discounted, it was possible to exclude migration and new mutation as major sources of changes in the frequency of these alleles by limiting analyses to pedigrees descendant from founding families. Calculations which overestimated the possible effect of random drift demonstrated that drift did not account for the observed changes in gene frequencies. Therefore these changes must have been caused by natural selection, and a coefficient of selection was estimated for each trait. For the rare, dominant, deleterious allele associated with Huntington disease, the coefficient of selection was estimated to be .34, indicating that this allele has a selective disadvantage, contrary to some recent studies. For the presumed dominant and probably deleterious allele associated with porphyria variegata, the coefficient of selection lies between .07 and .02. The coefficient of selection for the rare, clinically recessive allele associated with lipoid proteinosis was estimated to be .07. Calculations based on a model system indicate that the observed decrease in allele frequency cannot be explained solely on the basis of selection against the homozygote. Thus, this may be an example of a pleiotropic gene which has a dominant effect in terms of selection even though its known clinical effect is recessive. PMID:2137963

The estimation of selection coefficients in Afrikaners: Huntington disease, porphyria variegata, and lipoid proteinosis.

PubMed

Stine, O C; Smith, K D

1990-03-01

The effects of mutation, migration, random drift, and selection on the change in frequency of the alleles associated with Huntington disease, porphyria variegata, and lipoid proteinosis have been assessed in the Afrikaner population of South Africa. Although admixture cannot be completely discounted, it was possible to exclude migration and new mutation as major sources of changes in the frequency of these alleles by limiting analyses to pedigrees descendant from founding families. Calculations which overestimated the possible effect of random drift demonstrated that drift did not account for the observed changes in gene frequencies. Therefore these changes must have been caused by natural selection, and a coefficient of selection was estimated for each trait. For the rare, dominant, deleterious allele associated with Huntington disease, the coefficient of selection was estimated to be .34, indicating that this allele has a selective disadvantage, contrary to some recent studies. For the presumed dominant and probably deleterious allele associated with porphyria variegata, the coefficient of selection lies between .07 and .02. The coefficient of selection for the rare, clinically recessive allele associated with lipoid proteinosis was estimated to be .07. Calculations based on a model system indicate that the observed decrease in allele frequency cannot be explained solely on the basis of selection against the homozygote. Thus, this may be an example of a pleiotropic gene which has a dominant effect in terms of selection even though its known clinical effect is recessive.

Mixing rates and limit theorems for random intermittent maps

NASA Astrophysics Data System (ADS)

Bahsoun, Wael; Bose, Christopher

2016-04-01

We study random transformations built from intermittent maps on the unit interval that share a common neutral fixed point. We focus mainly on random selections of Pomeu-Manneville-type maps {{T}α} using the full parameter range 0<α <∞ , in general. We derive a number of results around a common theme that illustrates in detail how the constituent map that is fastest mixing (i.e. smallest α) combined with details of the randomizing process, determines the asymptotic properties of the random transformation. Our key result (theorem 1.1) establishes sharp estimates on the position of return time intervals for the quenched dynamics. The main applications of this estimate are to limit laws (in particular, CLT and stable laws, depending on the parameters chosen in the range 0<α <1 ) for the associated skew product; these are detailed in theorem 3.2. Since our estimates in theorem 1.1 also hold for 1≤slant α <∞ we study a second class of random transformations derived from piecewise affine Gaspard-Wang maps, prove existence of an infinite (σ-finite) invariant measure and study the corresponding correlation asymptotics. To the best of our knowledge, this latter kind of result is completely new in the setting of random transformations.

Effects of one versus two bouts of moderate intensity physical activity on selective attention during a school morning in Dutch primary schoolchildren: A randomized controlled trial.

PubMed

Altenburg, Teatske M; Chinapaw, Mai J M; Singh, Amika S

2016-10-01

Evidence suggests that physical activity is positively related to several aspects of cognitive functioning in children, among which is selective attention. To date, no information is available on the optimal frequency of physical activity on cognitive functioning in children. The current study examined the acute effects of one and two bouts of moderate-intensity physical activity on children's selective attention. Randomized controlled trial (ISRCTN97975679). Thirty boys and twenty-six girls, aged 10-13 years, were randomly assigned to three conditions: (A) sitting all morning working on simulated school tasks; (B) one 20-min physical activity bout after 90min; and (C) two 20-min physical activity bouts, i.e. at the start and after 90min. Selective attention was assessed at five time points during the morning (i.e. at baseline and after 20, 110, 130 and 220min), using the 'Sky Search' subtest of the 'Test of Selective Attention in Children'. We used GEE analysis to examine differences in Sky Search scores between the three experimental conditions, adjusting for school, baseline scores, self-reported screen time and time spent in sports. Children who performed two 20-min bouts of moderate-intensity physical activity had significantly better Sky Search scores compared to children who performed one physical activity bout or remained seated the whole morning (B=-0.26; 95% CI=[-0.52; -0.00]). Our findings support the importance of repeated physical activity during the school day for beneficial effects on selective attention in children. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

A review of selection-based tests of abiotic surrogates for species representation.

PubMed

Beier, Paul; Sutcliffe, Patricia; Hjort, Jan; Faith, Daniel P; Pressey, Robert L; Albuquerque, Fabio

2015-06-01

Because conservation planners typically lack data on where species occur, environmental surrogates--including geophysical settings and climate types--have been used to prioritize sites within a planning area. We reviewed 622 evaluations of the effectiveness of abiotic surrogates in representing species in 19 study areas. Sites selected using abiotic surrogates represented more species than an equal number of randomly selected sites in 43% of tests (55% for plants) and on average improved on random selection of sites by about 8% (21% for plants). Environmental diversity (ED) (42% median improvement on random selection) and biotically informed clusters showed promising results and merit additional testing. We suggest 4 ways to improve performance of abiotic surrogates. First, analysts should consider a broad spectrum of candidate variables to define surrogates, including rarely used variables related to geographic separation, distance from coast, hydrology, and within-site abiotic diversity. Second, abiotic surrogates should be defined at fine thematic resolution. Third, sites (the landscape units prioritized within a planning area) should be small enough to ensure that surrogates reflect species' environments and to produce prioritizations that match the spatial resolution of conservation decisions. Fourth, if species inventories are available for some planning units, planners should define surrogates based on the abiotic variables that most influence species turnover in the planning area. Although species inventories increase the cost of using abiotic surrogates, a modest number of inventories could provide the data needed to select variables and evaluate surrogates. Additional tests of nonclimate abiotic surrogates are needed to evaluate the utility of conserving nature's stage as a strategy for conservation planning in the face of climate change. © 2015 Society for Conservation Biology.

Mirnacle: machine learning with SMOTE and random forest for improving selectivity in pre-miRNA ab initio prediction.

PubMed

Marques, Yuri Bento; de Paiva Oliveira, Alcione; Ribeiro Vasconcelos, Ana Tereza; Cerqueira, Fabio Ribeiro

2016-12-15

MicroRNAs (miRNAs) are key gene expression regulators in plants and animals. Therefore, miRNAs are involved in several biological processes, making the study of these molecules one of the most relevant topics of molecular biology nowadays. However, characterizing miRNAs in vivo is still a complex task. As a consequence, in silico methods have been developed to predict miRNA loci. A common ab initio strategy to find miRNAs in genomic data is to search for sequences that can fold into the typical hairpin structure of miRNA precursors (pre-miRNAs). The current ab initio approaches, however, have selectivity issues, i.e., a high number of false positives is reported, which can lead to laborious and costly attempts to provide biological validation. This study presents an extension of the ab initio method miRNAFold, with the aim of improving selectivity through machine learning techniques, namely, random forest combined with the SMOTE procedure that copes with imbalance datasets. By comparing our method, termed Mirnacle, with other important approaches in the literature, we demonstrate that Mirnacle substantially improves selectivity without compromising sensitivity. For the three datasets used in our experiments, our method achieved at least 97% of sensitivity and could deliver a two-fold, 20-fold, and 6-fold increase in selectivity, respectively, compared with the best results of current computational tools. The extension of miRNAFold by the introduction of machine learning techniques, significantly increases selectivity in pre-miRNA ab initio prediction, which optimally contributes to advanced studies on miRNAs, as the need of biological validations is diminished. Hopefully, new research, such as studies of severe diseases caused by miRNA malfunction, will benefit from the proposed computational tool.

The relationship between environmental exposure to cadmium and lead and blood selenium concentration in randomly selected population of children inhabiting industrial regions of Silesian Voivodship (Poland).

PubMed

Gać, P; Pawlas, N; Poręba, R; Poręba, M; Pawlas, K

2014-06-01

This study aimed at determining the relationship between environmental exposure to lead (Pb) and cadmium (Cd) and blood selenium (Se) concentration in randomly selected population of children inhabiting the industrial regions of Silesian Voivodship, Poland. The study was conducted on a group of consecutive randomly selected 349 children aged below 15 years and inhabiting the industrial regions in Upper Silesia. The examined variables included whole blood Cd concentration (Cd-B), whole blood Pb concentration (Pb-B) and whole blood Se concentration (Se-B). The concentration of Cd-B, Pb-B and Se-B in the studied group of children amounted to 0.26 ± 0.14, 37.62 ± 25.30 and 78.31 ± 12.82 μg/L, respectively. In the entire examined group a statistically significant negative linear relationship was noted between Pb-B and Se-B (r = -0.12, p < 0.05). Also, a statistically insignificant negative correlation was detected between Cd-B and Se-B (r = -0.02, p > 0.05) and a statistically insignificant positive correlation between Pb-B and Cd-B (r = 0.08, p > 0.05). A multivariate backward stepwise regression analysis demonstrated that in the studied group of children higher Pb-B and a more advanced age-represented independent risk factors for a decreased Se-B. Environmental exposure to Pb may represent an independent risk factor for Se deficit in blood of the studied population of children. In children, the lowered Se-B may create one of the mechanisms in which Pb unfavourably affects human body. © The Author(s) 2014.

Oral Administration of Lactobacillus plantarum 299v Reduces Cortisol Levels in Human Saliva during Examination Induced Stress: A Randomized, Double-Blind Controlled Trial.

PubMed

Andersson, Hannah; Tullberg, Cecilia; Ahrné, Siv; Hamberg, Kristina; Lazou Ahrén, Irini; Molin, Göran; Sonesson, Mikael; Håkansson, Åsa

2016-01-01

Objective . To clarify the effect of Lactobacillus plantarum 299v on the salivary cortisol and salivary IgA levels in young adults under examination stress. Design . Forty-one students with an upcoming academic exam were included in a randomized double-blind, placebo-controlled study. The probiotic bacteria or the placebo product was administered in capsules once a day during 14 days. Saliva was collected and a perceived stress test was filled out at each sampling occasion. Saliva was collected for cortisol analysis by Electrochemiluminescence Immunoassay (ECLI) and salivary IgA was analysed by Enzyme-Linked Immunosorbent Assay (ELISA). Abundance of lactobacilli was evaluated by cultivation of saliva on selective medium and identification of L. plantarum 299v was done on randomly selected colonies by a random amplification of polymorphic DNA (RAPD) typing. Results . A significant difference in cortisol levels was found between the treatment group and the placebo group ( P < 0.05), together with a significant increase in levels of lactobacilli in the treatment group compared with the placebo group ( P < 0.001). No significant changes were found for salivary IgA. Conclusion . A probiotic bacterium with ability to reduce symptoms of irritable bowel syndrome (IBS) prohibited increased levels of the stress marker cortisol during the examination period. The registration number of the study is NCT02974894, and the study is registered at ClinicalTrials.gov.

Oral Administration of Lactobacillus plantarum 299v Reduces Cortisol Levels in Human Saliva during Examination Induced Stress: A Randomized, Double-Blind Controlled Trial

PubMed Central

Andersson, Hannah; Tullberg, Cecilia; Ahrné, Siv; Hamberg, Kristina; Lazou Ahrén, Irini; Molin, Göran; Sonesson, Mikael

2016-01-01

Objective. To clarify the effect of Lactobacillus plantarum 299v on the salivary cortisol and salivary IgA levels in young adults under examination stress. Design. Forty-one students with an upcoming academic exam were included in a randomized double-blind, placebo-controlled study. The probiotic bacteria or the placebo product was administered in capsules once a day during 14 days. Saliva was collected and a perceived stress test was filled out at each sampling occasion. Saliva was collected for cortisol analysis by Electrochemiluminescence Immunoassay (ECLI) and salivary IgA was analysed by Enzyme-Linked Immunosorbent Assay (ELISA). Abundance of lactobacilli was evaluated by cultivation of saliva on selective medium and identification of L. plantarum 299v was done on randomly selected colonies by a random amplification of polymorphic DNA (RAPD) typing. Results. A significant difference in cortisol levels was found between the treatment group and the placebo group (P < 0.05), together with a significant increase in levels of lactobacilli in the treatment group compared with the placebo group (P < 0.001). No significant changes were found for salivary IgA. Conclusion. A probiotic bacterium with ability to reduce symptoms of irritable bowel syndrome (IBS) prohibited increased levels of the stress marker cortisol during the examination period. The registration number of the study is NCT02974894, and the study is registered at ClinicalTrials.gov. PMID:28101105

Analysis of training sample selection strategies for regression-based quantitative landslide susceptibility mapping methods

NASA Astrophysics Data System (ADS)

Erener, Arzu; Sivas, A. Abdullah; Selcuk-Kestel, A. Sevtap; Düzgün, H. Sebnem

2017-07-01

All of the quantitative landslide susceptibility mapping (QLSM) methods requires two basic data types, namely, landslide inventory and factors that influence landslide occurrence (landslide influencing factors, LIF). Depending on type of landslides, nature of triggers and LIF, accuracy of the QLSM methods differs. Moreover, how to balance the number of 0 (nonoccurrence) and 1 (occurrence) in the training set obtained from the landslide inventory and how to select which one of the 1's and 0's to be included in QLSM models play critical role in the accuracy of the QLSM. Although performance of various QLSM methods is largely investigated in the literature, the challenge of training set construction is not adequately investigated for the QLSM methods. In order to tackle this challenge, in this study three different training set selection strategies along with the original data set is used for testing the performance of three different regression methods namely Logistic Regression (LR), Bayesian Logistic Regression (BLR) and Fuzzy Logistic Regression (FLR). The first sampling strategy is proportional random sampling (PRS), which takes into account a weighted selection of landslide occurrences in the sample set. The second method, namely non-selective nearby sampling (NNS), includes randomly selected sites and their surrounding neighboring points at certain preselected distances to include the impact of clustering. Selective nearby sampling (SNS) is the third method, which concentrates on the group of 1's and their surrounding neighborhood. A randomly selected group of landslide sites and their neighborhood are considered in the analyses similar to NNS parameters. It is found that LR-PRS, FLR-PRS and BLR-Whole Data set-ups, with order, yield the best fits among the other alternatives. The results indicate that in QLSM based on regression models, avoidance of spatial correlation in the data set is critical for the model's performance.

Study Habits and Academic Achievement of Kashmiri & Ladakhi Adolescent Girls: A Comparative Study

ERIC Educational Resources Information Center

Nadeem, N. A.; Puja, Javeed Ahamd; Bhat, Shabir Ahmad

2014-01-01

The present study was conducted to study the Study Habits and Academic Achievement of Adolescents girls in Jammu and Kashmir. 400 sample subjects were selected randomly from two ethnic groups' viz. Kashmiri and Ladakhi. The investigators used Palsane & Sharma's study habits inventory (PSSHI) to collect data from the field. Certain statistical…

Inference from habitat-selection analysis depends on foraging strategies.

PubMed

Bastille-Rousseau, Guillaume; Fortin, Daniel; Dussault, Christian

2010-11-01

1. Several methods have been developed to assess habitat selection, most of which are based on a comparison between habitat attributes in used vs. unused or random locations, such as the popular resource selection functions (RSFs). Spatial evaluation of residency time has been recently proposed as a promising avenue for studying habitat selection. Residency-time analyses assume a positive relationship between residency time within habitat patches and selection. We demonstrate that RSF and residency-time analyses provide different information about the process of habitat selection. Further, we show how the consideration of switching rate between habitat patches (interpatch movements) together with residency-time analysis can reveal habitat-selection strategies. 2. Spatially explicit, individual-based modelling was used to simulate foragers displaying one of six foraging strategies in a heterogeneous environment. The strategies combined one of three patch-departure rules (fixed-quitting-harvest-rate, fixed-time and fixed-amount strategy), together with one of two interpatch-movement rules (random or biased). Habitat selection of simulated foragers was then assessed using RSF, residency-time and interpatch-movement analyses. 3. Our simulations showed that RSFs and residency times are not always equivalent. When foragers move in a non-random manner and do not increase residency time in richer patches, residency-time analysis can provide misleading assessments of habitat selection. This is because the overall time spent in the various patch types not only depends on residency times, but also on interpatch-movement decisions. 4. We suggest that RSFs provide the outcome of the entire selection process, whereas residency-time and interpatch-movement analyses can be used in combination to reveal the mechanisms behind the selection process. 5. We showed that there is a risk in using residency-time analysis alone to infer habitat selection. Residency-time analyses, however, may enlighten the mechanisms of habitat selection by revealing central components of resource-use strategies. Given that management decisions are often based on resource-selection analyses, the evaluation of resource-use strategies can be key information for the development of efficient habitat-management strategies. Combining RSF, residency-time and interpatch-movement analyses is a simple and efficient way to gain a more comprehensive understanding of habitat selection. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.

Traffic signal inventory project

DOT National Transportation Integrated Search

2001-06-01

The purpose of this study was to determine the level of compliance with the "Manual on Uniform Traffic Control Devices" (MUTCD) and other industry standards of traffic signals on the Iowa state highway system. Signals were randomly selected in cities...

Random bit generation at tunable rates using a chaotic semiconductor laser under distributed feedback.

PubMed

Li, Xiao-Zhou; Li, Song-Sui; Zhuang, Jun-Ping; Chan, Sze-Chun

2015-09-01

A semiconductor laser with distributed feedback from a fiber Bragg grating (FBG) is investigated for random bit generation (RBG). The feedback perturbs the laser to emit chaotically with the intensity being sampled periodically. The samples are then converted into random bits by a simple postprocessing of self-differencing and selecting bits. Unlike a conventional mirror that provides localized feedback, the FBG provides distributed feedback which effectively suppresses the information of the round-trip feedback delay time. Randomness is ensured even when the sampling period is commensurate with the feedback delay between the laser and the grating. Consequently, in RBG, the FBG feedback enables continuous tuning of the output bit rate, reduces the minimum sampling period, and increases the number of bits selected per sample. RBG is experimentally investigated at a sampling period continuously tunable from over 16 ns down to 50 ps, while the feedback delay is fixed at 7.7 ns. By selecting 5 least-significant bits per sample, output bit rates from 0.3 to 100 Gbps are achieved with randomness examined by the National Institute of Standards and Technology test suite.

Does albendazole affect seizure remission and computed tomography response in children with neurocysticercosis? A Systematic review and meta-analysis.

PubMed

Mazumdar, Maitreyi; Pandharipande, Pari; Poduri, Annapurna

2007-02-01

A recent trial suggested that albendazole reduces seizures in adults with neurocysticercosis. There is still no consensus regarding optimal management of neurocysticercosis in children. The authors conducted a systematic review and meta-analysis to assess the efficacy of albendazole in children with neurocysticercosis, by searching the Cochrane Databases, MEDLINE, EMBASE, and LILACS. Three reviewers extracted data using an intent-to-treat analysis. Random effects models were used to estimate relative risks. Four randomized trials were selected for meta-analysis, and 10 observational studies were selected for qualitative review. The relative risk of seizure remission in treatment versus control was 1.26 (1.09, 1.46). The relative risk of improvement in computed tomography in these trials was 1.15 (0.97, 1.36). Review of observational studies showed conflicting results, likely owing to preferential administration of albendazole to sicker children.

Transcranial direct current stimulation to primary motor area improves hand dexterity and selective attention in chronic stroke.

PubMed

Au-Yeung, Stephanie S Y; Wang, Juliana; Chen, Ye; Chua, Eldrich

2014-12-01

The aim of this study was to determine whether transcranial direct current stimulation (tDCS) applied to the primary motor hand area modulates hand dexterity and selective attention after stroke. This study was a double-blind, placebo-controlled, randomized crossover trial involving subjects with chronic stroke. Ten stroke survivors with some pinch strength in the paretic hand received three different tDCS interventions assigned in random order in separate sessions-anodal tDCS targeting the primary motor area of the lesioned hemisphere (M1lesioned), cathodal tDCS applied to the contralateral hemisphere (M1nonlesioned), and sham tDCS-each for 20 mins. The primary outcome measures were Purdue pegboard test scores for hand dexterity and response time in the color-word Stroop test for selective attention. Pinch strength of the paretic hand was the secondary outcome. Cathodal tDCS to M1nonlesioned significantly improved affected hand dexterity (by 1.1 points on the Purdue pegboard unimanual test, P = 0.014) and selective attention (0.6 secs faster response time on the level 3 Stroop interference test for response inhibition, P = 0.017), but not pinch strength. The outcomes were not improved with anodal tDCS to M1lesioned or sham tDCS. Twenty minutes of cathodal tDCS to M1nonlesioned can promote both paretic hand dexterity and selective attention in people with chronic stroke.

Optimization Of Mean-Semivariance-Skewness Portfolio Selection Model In Fuzzy Random Environment

NASA Astrophysics Data System (ADS)

Chatterjee, Amitava; Bhattacharyya, Rupak; Mukherjee, Supratim; Kar, Samarjit

2010-10-01

The purpose of the paper is to construct a mean-semivariance-skewness portfolio selection model in fuzzy random environment. The objective is to maximize the skewness with predefined maximum risk tolerance and minimum expected return. Here the security returns in the objectives and constraints are assumed to be fuzzy random variables in nature and then the vagueness of the fuzzy random variables in the objectives and constraints are transformed into fuzzy variables which are similar to trapezoidal numbers. The newly formed fuzzy model is then converted into a deterministic optimization model. The feasibility and effectiveness of the proposed method is verified by numerical example extracted from Bombay Stock Exchange (BSE). The exact parameters of fuzzy membership function and probability density function are obtained through fuzzy random simulating the past dates.

Close woods utilization commonly practiced in Delaware

Treesearch

Wayne G. Banks

1956-01-01

Woods-utilization studies were recently made on randomly selected logging operations scattered throughout Delaware. As would be expected, most of the operations studied were in pine stands in the southern part of the state. They showed that very close utilization of the trees cut was the general rule.

Enhancing Employee Skills.

ERIC Educational Resources Information Center

1999

This document contains four symposium papers on enhancing employee skills. "The Effect of Study Skills Training Intervention on United States Air Force Aeromedical Apprentices" (John C. Griffith) demonstrates how study skills intervention resulted in a significant increase in the end-of-course scores of a sample of 90 randomly selected Air Force…

Which Approach Is More Effective in the Selection of Plants with Antimicrobial Activity?

PubMed Central

Silva, Ana Carolina Oliveira; Santana, Elidiane Fonseca; Saraiva, Antonio Marcos; Coutinho, Felipe Neves; Castro, Ricardo Henrique Acre; Pisciottano, Maria Nelly Caetano; Amorim, Elba Lúcia Cavalcanti; Albuquerque, Ulysses Paulino

2013-01-01

The development of the present study was based on selections using random, direct ethnopharmacological, and indirect ethnopharmacological approaches, aiming to evaluate which method is the best for bioprospecting new antimicrobial plant drugs. A crude extract of 53 species of herbaceous plants collected in the semiarid region of Northeast Brazil was tested against 11 microorganisms. Well-agar diffusion and minimum inhibitory concentration (MIC) techniques were used. Ten extracts from direct, six from random, and three from indirect ethnopharmacological selections exhibited activities that ranged from weak to very active against the organisms tested. The strain most susceptible to the evaluated extracts was Staphylococcus aureus. The MIC analysis revealed the best result for the direct ethnopharmacological approach, considering that some species yielded extracts classified as active or moderately active (MICs between 250 and 1000 µg/mL). Furthermore, one species from this approach inhibited the growth of the three Candida strains. Thus, it was concluded that the direct ethnopharmacological approach is the most effective when selecting species for bioprospecting new plant drugs with antimicrobial activities. PMID:23878595

Probabilistic pathway construction.

PubMed

Yousofshahi, Mona; Lee, Kyongbum; Hassoun, Soha

2011-07-01

Expression of novel synthesis pathways in host organisms amenable to genetic manipulations has emerged as an attractive metabolic engineering strategy to overproduce natural products, biofuels, biopolymers and other commercially useful metabolites. We present a pathway construction algorithm for identifying viable synthesis pathways compatible with balanced cell growth. Rather than exhaustive exploration, we investigate probabilistic selection of reactions to construct the pathways. Three different selection schemes are investigated for the selection of reactions: high metabolite connectivity, low connectivity and uniformly random. For all case studies, which involved a diverse set of target metabolites, the uniformly random selection scheme resulted in the highest average maximum yield. When compared to an exhaustive search enumerating all possible reaction routes, our probabilistic algorithm returned nearly identical distributions of yields, while requiring far less computing time (minutes vs. years). The pathways identified by our algorithm have previously been confirmed in the literature as viable, high-yield synthesis routes. Prospectively, our algorithm could facilitate the design of novel, non-native synthesis routes by efficiently exploring the diversity of biochemical transformations in nature. Copyright © 2011 Elsevier Inc. All rights reserved.

Measuring CAMD technique performance. 2. How "druglike" are drugs? Implications of Random test set selection exemplified using druglikeness classification models.

PubMed

Good, Andrew C; Hermsmeier, Mark A

2007-01-01

Research into the advancement of computer-aided molecular design (CAMD) has a tendency to focus on the discipline of algorithm development. Such efforts are often wrought to the detriment of the data set selection and analysis used in said algorithm validation. Here we highlight the potential problems this can cause in the context of druglikeness classification. More rigorous efforts are applied to the selection of decoy (nondruglike) molecules from the ACD. Comparisons are made between model performance using the standard technique of random test set creation with test sets derived from explicit ontological separation by drug class. The dangers of viewing druglike space as sufficiently coherent to permit simple classification are highlighted. In addition the issues inherent in applying unfiltered data and random test set selection to (Q)SAR models utilizing large and supposedly heterogeneous databases are discussed.

Radiofrequency and Microwave Ablation Compared to Systemic Chemotherapy and to Partial Hepatectomy in the Treatment of Colorectal Liver Metastases: A Systematic Review and Meta-Analysis.

PubMed

Meijerink, Martijn R; Puijk, Robbert S; van Tilborg, Aukje A J M; Henningsen, Kirsten Holdt; Fernandez, Llenalia Garcia; Neyt, Mattias; Heymans, Juanita; Frankema, Jacqueline S; de Jong, Koert P; Richel, Dick J; Prevoo, Warner; Vlayen, Joan

2018-04-17

To assess safety and outcome of radiofrequency ablation (RFA) and microwave ablation (MWA) as compared to systemic chemotherapy and partial hepatectomy (PH) in the treatment of colorectal liver metastases (CRLM). MEDLINE, Embase and the Cochrane Library were searched. Randomized trials and comparative observational studies with multivariate analysis and/or matching were included. Guidelines from National Guideline Clearinghouse and Guidelines International Network were assessed using the AGREE II instrument. The search revealed 3530 records; 328 were selected for full-text review; 48 were included: 8 systematic reviews, 2 randomized studies, 26 comparative observational studies, 2 guideline-articles and 10 case series; in addition 13 guidelines were evaluated. Literature to assess the effectiveness of ablation was limited. RFA + systemic chemotherapy was superior to chemotherapy alone. PH was superior to RFA alone but not to RFA + PH or to MWA. Compared to PH, RFA showed fewer complications, MWA did not. Outcomes were subject to residual confounding since ablation was only employed for unresectable disease. The results from the EORTC-CLOCC trial, the comparable survival for ablation + PH versus PH alone, the potential to induce long-term disease control and the low complication rate argue in favour of ablation over chemotherapy alone. Further randomized comparisons of ablation to current-day chemotherapy alone should therefore be considered unethical. Hence, the highest achievable level of evidence for unresectable CRLM seems reached. The apparent selection bias from previous studies and the superior safety profile mandate the setup of randomized controlled trials comparing ablation to surgery.

Physical Activity Related to Depression and Predicted Mortality Risk: Results from the Americans' Changing Lives Study

ERIC Educational Resources Information Center

Lee, Pai-Lin; Lan, William; Lee, Charles C.-L.

2012-01-01

This study examined the association between three types of physical activities (PA) and depression, and the relationship between PA and later mortality. Previous studies rarely assessed these associations in one single study in randomly selected population samples. Few studies have assessed these relations by adjusting the covariate of…

Assessment of Social Media Utilization and Study Habit of Students of Tertiary Institutions in Katsina State

ERIC Educational Resources Information Center

Olutola, Adekunle Thomas; Olatoye, Olufunke Omotoke; Olatoye, Rafiu Ademola

2016-01-01

This study investigated assessment of social media utilization and study habits of students of tertiary institutions in Katsina State. The descriptive survey design was adopted for this study. Three hundred and eighty-one (381) students' of tertiary institutions in Katsina State were randomly selected for the study. Researchers'-designed…

The Selection and Prevalence of Natural and Fortified Calcium Food Sources in the Diets of Adolescent Girls

ERIC Educational Resources Information Center

Rafferty, Karen; Watson, Patrice; Lappe, Joan M.

2011-01-01

Objective: To assess the impact of calcium-fortified food and dairy food on selected nutrient intakes in the diets of adolescent girls. Design: Randomized controlled trial, secondary analysis. Setting and Participants: Adolescent girls (n = 149) from a midwestern metropolitan area participated in randomized controlled trials of bone physiology…

A National Survey of Chief Student Personnel Officers at Randomly Selected Institutions of Postsecondary Education in the United States.

ERIC Educational Resources Information Center

Thomas, Henry B.; Kaplan, E. Joseph

A national survey was conducted of randomly selected chief student personnel officers as listed in the 1979 "Education Directory of Colleges and Universities." The survey addressed specific institutional demographics, policy-making authority, reporting structure, and areas of responsibility of the administrators. Over 93 percent of the respondents…

TOC: Table of Contents Practices of Primary Journals--Recommendations for Monolingual, Multilingual and International Journals.

ERIC Educational Resources Information Center

Juhasz, Stephen; And Others

Table of contents (TOC) practices of some 120 primary journals were analyzed. The journals were randomly selected. The method of randomization is described. The samples were selected from a university library with a holding of approximately 12,000 titles published worldwide. A questionnaire was designed. Purpose was to find uniformity and…

Molecular selection in a unified evolutionary sequence

NASA Technical Reports Server (NTRS)

Fox, S. W.

1986-01-01

With guidance from experiments and observations that indicate internally limited phenomena, an outline of unified evolutionary sequence is inferred. Such unification is not visible for a context of random matrix and random mutation. The sequence proceeds from Big Bang through prebiotic matter, protocells, through the evolving cell via molecular and natural selection, to mind, behavior, and society.

Selection of Variables in Cluster Analysis: An Empirical Comparison of Eight Procedures

ERIC Educational Resources Information Center

Steinley, Douglas; Brusco, Michael J.

2008-01-01

Eight different variable selection techniques for model-based and non-model-based clustering are evaluated across a wide range of cluster structures. It is shown that several methods have difficulties when non-informative variables (i.e., random noise) are included in the model. Furthermore, the distribution of the random noise greatly impacts the…

The Social Security Administration's Youth Transition Demonstration Projects: Implementation Lessons from the Original Projects

ERIC Educational Resources Information Center

Martinez, John; Fraker, Thomas; Manno, Michelle; Baird, Peter; Mamun, Arif; O'Day, Bonnie; Rangarajan, Anu; Wittenburg, David

2010-01-01

This report focuses on the seven original Youth Transition Demonstration (YTD) projects selected for funding in 2003. Three of the original seven projects were selected for a national random assignment evaluation in 2005; however, this report only focuses on program operations prior to joining the random assignment evaluation for the three…

On the Choice of Adequate Randomization Ranges for Limiting the Use of Unwanted Cues in Same-Different, Dual-Pair, and Oddity Tasks

PubMed Central

Dai, Huanping; Micheyl, Christophe

2010-01-01

A major concern when designing a psychophysical experiment is that participants may use another stimulus feature (“cue”) than that intended by the experimenter. One way to avoid this involves applying random variations to the corresponding feature across stimulus presentations, to make the “unwanted” cue unreliable. An important question facing experimenters who use this randomization (“roving”) technique is: How large should the randomization range be to ensure that participants cannot achieve a certain proportion correct (PC) by using the unwanted cue, while at the same time avoiding unnecessary interference of the randomization with task performance? Previous publications have provided formulas for the selection of adequate randomization ranges in yes-no and multiple-alternative, forced-choice tasks. In this article, we provide figures and tables, which can be used to select randomization ranges that are better suited to experiments involving a same-different, dual-pair, or oddity task. PMID:20139466

Evaluation of reference genes for reverse transcription quantitative real-time PCR (RT-qPCR) studies in Silene vulgaris considering the method of cDNA preparation

PubMed Central

Koloušková, Pavla; Stone, James D.

2017-01-01

Accurate gene expression measurements are essential in studies of both crop and wild plants. Reverse transcription quantitative real-time PCR (RT-qPCR) has become a preferred tool for gene expression estimation. A selection of suitable reference genes for the normalization of transcript levels is an essential prerequisite of accurate RT-qPCR results. We evaluated the expression stability of eight candidate reference genes across roots, leaves, flower buds and pollen of Silene vulgaris (bladder campion), a model plant for the study of gynodioecy. As random priming of cDNA is recommended for the study of organellar transcripts and poly(A) selection is indicated for nuclear transcripts, we estimated gene expression with both random-primed and oligo(dT)-primed cDNA. Accordingly, we determined reference genes that perform well with oligo(dT)- and random-primed cDNA, making it possible to estimate levels of nucleus-derived transcripts in the same cDNA samples as used for organellar transcripts, a key benefit in studies of cyto-nuclear interactions. Gene expression variance was estimated by RefFinder, which integrates four different analytical tools. The SvACT and SvGAPDH genes were the most stable candidates across various organs of S. vulgaris, regardless of whether pollen was included or not. PMID:28817728

Randomized trials published in Chinese or Western journals: comparative empirical analysis.

PubMed

Purgato, Marianna; Cipriani, Andrea; Barbui, Corrado

2012-06-01

A major concern to the inclusion in systematic reviews of studies originating in China and published in Chinese journals refers to the quality of study reporting. In this systematic survey of randomized trials, we compared the characteristics of studies published in Chinese journals with those of studies published in Western journals. We included 69 studies comparing citalopram with other antidepressant drugs in the treatment of major depression. Of these, 37 (54%) were published in Chinese journals. The standard of reporting was generally poor in both Western and Chinese studies. In some Chinese studies, the generation of the randomization sequence raised concern about their experimental nature, and in almost all included studies, the concealment of allocation was not properly described. Blinding was seldom adopted in Chinese studies, and the risk of sponsorship bias was uncertain because Chinese studies did not report any financial support. In most Western studies, outcome data were selectively and incompletely reported. Pooling together all trials revealed that citalopram was similarly effective in comparison with all other antidepressant drugs both in Western studies (standardized mean difference, -0.04; 95% confidence interval, -0.15 to 0.06) and in Chinese studies (standardized mean difference, -0.08, 95% confidence interval, -0.18 to 0.02). Randomized controlled trials published in Chinese journals represent most of the studies included in this review. This suggests that omitting to search biomedical databases originating from China would systematically exclude a relevant proportion of randomized trials published in Chinese journals, with a risk of random error or bias. The increasing inclusion of Chinese studies in systematic reviews reinforces the need to check the quality of randomized trials that are meta-analyzed.

Comparative effectiveness research in cancer with observational data.

PubMed

Giordano, Sharon H

2015-01-01

Observational studies are increasingly being used for comparative effectiveness research. These studies can have the greatest impact when randomized trials are not feasible or when randomized studies have not included the population or outcomes of interest. However, careful attention must be paid to study design to minimize the likelihood of selection biases. Analytic techniques, such as multivariable regression modeling, propensity score analysis, and instrumental variable analysis, also can also be used to help address confounding. Oncology has many existing large and clinically rich observational databases that can be used for comparative effectiveness research. With careful study design, observational studies can produce valid results to assess the benefits and harms of a treatment or intervention in representative real-world populations.

Cross-resistance to prosulfocarb + S-metolachlor and pyroxasulfone selected by either herbicide in Lolium rigidum.

PubMed

Busi, Roberto; Powles, Stephen B

2016-09-01

Weeds can be a greater constraint to crop production than animal pests and pathogens. Pre-emergence herbicides are crucial in many cropping systems to control weeds that have evolved resistance to selective post-emergence herbicides. In this study we assessed the potential to evolve resistance to the pre-emergence herbicides prosulfocarb + S-metolachlor or pyroxasulfone in 50 individual field Lolium rigidum populations collected in a random survey in Western Australia prior to commercialisation of these pre-emergence herbicides. This study shows for the first time that in randomly collected L. rigidum field populations the selection with either prosulfocarb + S-metolachlor or pyroxasulfone can result in concomitant evolution of resistance to both prosulfocarb + S-metolachlor and pyroxasulfone after three generations. In the major weed L. rigidum, traits conferring resistance to new herbicides can be present before herbicide commercialisation. Proactive and multidisciplinary research (evolutionary ecology, modelling and molecular biology) is required to detect and analyse resistant populations before they can appear in the field. Several studies show that evolved cross-resistance in weeds is complex and often unpredictable. Thus, long-term management of cross-resistant weeds must be achieved through heterogeneity of selection by effective chemical, cultural and physical weed control strategies that can delay herbicide resistance evolution. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Should Controls With Respiratory Symptoms Be Excluded From Case-Control Studies of Pneumonia Etiology? Reflections From the PERCH Study

PubMed Central

Hammitt, Laura L.; Deloria Knoll, Maria; Baggett, Henry C.; Brooks, W. Abdullah; Howie, Stephen R. C.; Kotloff, Karen L.; Levine, Orin S.; Madhi, Shabir A.; Murdoch, David R.; Scott, J. Anthony G.; Thea, Donald M.; Driscoll, Amanda J.; Karron, Ruth A.; Park, Daniel E.; Prosperi, Christine; Zeger, Scott L.; O’Brien, Katherine L.; Feikin, Daniel R.; O’Brien, Katherine L.; Levine, Orin S.; Knoll, Maria Deloria; Feikin, Daniel R.; DeLuca, Andrea N.; Driscoll, Amanda J.; Fu, Wei; Hammitt, Laura L.; Higdon, Melissa M.; Kagucia, E. Wangeci; Karron, Ruth A.; Li, Mengying; Park, Daniel E.; Prosperi, Christine; Wu, Zhenke; Zeger, Scott L.; Watson, Nora L.; Crawley, Jane; Murdoch, David R.; Brooks, W. Abdullah; Endtz, Hubert P.; Zaman, Khalequ; Goswami, Doli; Hossain, Lokman; Jahan, Yasmin; Ashraf, Hasan; Howie, Stephen R. C.; Ebruke, Bernard E.; Antonio, Martin; McLellan, Jessica; Machuka, Eunice; Shamsul, Arifin; Zaman, Syed M.A.; Mackenzie, Grant; Scott, J. Anthony G.; Awori, Juliet O.; Morpeth, Susan C.; Kamau, Alice; Kazungu, Sidi; Kotloff, Karen L.; Tapia, Milagritos D.; Sow, Samba O.; Sylla, Mamadou; Tamboura, Boubou; Onwuchekwa, Uma; Kourouma, Nana; Toure, Aliou; Madhi, Shabir A.; Moore, David P.; Adrian, Peter V.; Baillie, Vicky L.; Kuwanda, Locadiah; Mudau, Azwifarwi; Groome, Michelle J.; Baggett, Henry C.; Thamthitiwat, Somsak; Maloney, Susan A.; Bunthi, Charatdao; Rhodes, Julia; Sawatwong, Pongpun; Akarasewi, Pasakorn; Thea, Donald M.; Mwananyanda, Lawrence; Chipeta, James; Seidenberg, Phil; Mwansa, James; wa Somwe, Somwe; Kwenda, Geoffrey

2017-01-01

Abstract Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrollment or analyses. Herein we argue that selecting controls regardless of respiratory symptoms provides the least biased estimates of pneumonia etiology. We review 3 reasons investigators may choose to exclude controls with respiratory symptoms in light of epidemiologic principles of control selection and present data from the Pneumonia Etiology Research for Child Health (PERCH) study where relevant to assess their validity. We conclude that exclusion of controls with respiratory symptoms will result in biased estimates of etiology. Randomly selected community controls, with or without respiratory symptoms, as long as they do not meet the criteria for case-defining pneumonia, are most representative of the general population from which cases arose and the least subject to selection bias. PMID:28575354

Primordial and primary prevention programs for cardiovascular diseases: from risk assessment through risk communication to risk reduction. A review of the literature

PubMed Central

Lancarotte, Inês; Nobre, Moacyr Roberto

2016-01-01

The aim of this study was to identify and reflect on the methods employed by studies focusing on intervention programs for the primordial and primary prevention of cardiovascular diseases. The PubMed, EMBASE, SciVerse Hub-Scopus, and Cochrane Library electronic databases were searched using the terms ‘effectiveness AND primary prevention AND risk factors AND cardiovascular diseases’ for systematic reviews, meta-analyses, randomized clinical trials, and controlled clinical trials in the English language. A descriptive analysis of the employed strategies, theories, frameworks, applied activities, and measurement of the variables was conducted. Nineteen primary studies were analyzed. Heterogeneity was observed in the outcome evaluations, not only in the selected domains but also in the indicators used to measure the variables. There was also a predominance of repeated cross-sectional survey design, differences in community settings, and variability related to the randomization unit when randomization was implemented as part of the sample selection criteria; furthermore, particularities related to measures, limitations, and confounding factors were observed. The employed strategies, including their advantages and limitations, and the employed theories and frameworks are discussed, and risk communication, as the key element of the interventions, is emphasized. A methodological process of selecting and presenting the information to be communicated is recommended, and a systematic theoretical perspective to guide the communication of information is advised. The risk assessment concept, its essential elements, and the relevant role of risk perception are highlighted. It is fundamental for communication that statements targeting other people’s understanding be prepared using systematic data. PMID:27982169

Science Teacher Candidates' Learning and Studying Strategies in the Context of Self-Regulation

ERIC Educational Resources Information Center

Yilmaz, Özkan

2017-01-01

This study investigated the students' individual study and learning strategies. Toward this purpose, open ended question form was administered to 40 university students who have enrolled department of mathematics and science education, faculty of education. Students were selected randomly in all level of class. Qualitative research method was used…

Preferential predation of cool season grass seed by the common cricket (Acheta domesticus)

USDA-ARS?s Scientific Manuscript database

To determine if there might be a seed predation preference among forage grasses a laboratory study was conducted using the common cricket (Acheta domesticus L.). Six cool-season grasses were selected and feeding studies were conducted over a three day period. The study was designed as a randomized ...

A Study on Chocolate Consumption in Prospective Teachers

ERIC Educational Resources Information Center

Ozgen, Leyla

2016-01-01

This study was planned and conducted to determine the chocolate consumption habits of prospective teachers. The study population was comprised of students attending the Faculty of Education at Gazi University in Ankara and the sample consisted of 251 prospective teachers selected with simple random sampling. 96.4% and 3.6% of the prospective…

A Study of Teachers' Perception of Schools' Organizational Health in Osun State

ERIC Educational Resources Information Center

Omoyemiju, Michael Adeniyi; Adediwura, Alaba Adeyemi

2011-01-01

This study examined the teachers' perceptions of school organizational health (i.e. resource support, job satisfaction among staff, morale boosts, institutional integrity and initiating structure). Descriptive survey design was used for the study. The sample was composed of 330 secondary school teachers randomly selected from 283, 826 secondary…

Relationship between High School Students' Facebook Addiction and Loneliness Status

ERIC Educational Resources Information Center

Karakose, Turgut; Yirci, Ramazan; Uygun, Harun; Ozdemir, Tuncay Yavuz

2016-01-01

This study was conducted in order to analyze the relation between high school students' Facebook addiction and loneliness levels. The study was conducted with the relational screening model. The sample of the study consists of 712 randomly selected high school students. The data was collected using the Bergen Facebook Addiction Scale (BFAS) to…

An Analysis and Critique of Selected Social Studies Textbooks.

ERIC Educational Resources Information Center

Giannangelo, Duane M.; Kaplan, Mary Bene

The purpose of this paper is to evaluate four social studies textbooks recently under consideration for use by the Memphis (Tennessee) City Public Schools. The textbooks, chosen at random, are: "World Geography: A Physical and Cultural Study" (de Blij and others, Scott Foresman, 1989); "A History of the United States" (Boorstin…

Mental Computation: Evidence from Fifth Graders

ERIC Educational Resources Information Center

Erdem, Emrullah

2017-01-01

The current study examines the mental computation performance owned by students at fifth grade. This study was carried out with 118 fifth graders (11-12-year-olds) studying at 3 randomly selected primary schools that served low and middle socio-economic areas in a city of Turkey. "Mental Computation Test (MCT)" has been used to reach how…

Social Studies Concepts: An Analysis of the NAEP and States' Standards

ERIC Educational Resources Information Center

Lord, Kathleen M.; Noel, Andrea M.; Slevin, Bridgette

2016-01-01

This study examined the 4th-grade National Assessment of Educational Progress (NAEP) assessments (history, geography, and civics) and 3rd- and 4th-grade social studies standards from nine randomly selected states and organized the content around three global concepts (conflict, movement, discovery) and six specific concepts (war, rebellion,…

Selective internal radiotherapy (SIRT) versus transarterial chemoembolization (TACE) for the treatment of intrahepatic cholangiocellular carcinoma (CCC): study protocol for a randomized controlled trial.

PubMed

Kloeckner, Roman; Ruckes, Christian; Kronfeld, Kai; Wörns, Marcus Alexander; Weinmann, Arndt; Galle, Peter Robert; Lang, Hauke; Otto, Gerd; Eichhorn, Waltraud; Schreckenberger, Mathias; Dueber, Christoph; Pitton, Michael Bernhard

2014-08-06

Cholangiocellular carcinoma is the second most common primary liver cancer after hepatocellular carcinoma. Over the last 30 years, the incidence of intrahepatic cholangiocellular carcinoma has risen continuously worldwide. Meanwhile, the intrahepatic cholangiocellular carcinoma has become more common than the extrahepatic growth type and currently accounts for 10-15% of all primary hepatic malignancies. Intrahepatic cholangiocellular carcinoma is typically diagnosed in advanced stages due to late clinical symptoms and an absence of classic risk factors. A late diagnosis precludes curative surgical resection. There is evidence that transarterial chemoembolization leads to better local tumor control and prolongs survival compared to systemic chemotherapy. New data indicates that selective internal radiotherapy, also referred to as radioembolization, provides promising results for treating intrahepatic cholangiocellular carcinoma. This pilot study is a randomized, controlled, single center, phase II trial. Twenty-four patients with intrahepatic cholangiocellular carcinoma will be randomized in a 1:1 ratio to receive either chemoembolization or radioembolization. Randomization will be stratified according to tumor load. Progression-free survival is the primary endpoint; overall survival and time to progression are secondary endpoints. To evaluate treatment success, patients will receive contrast enhanced magnetic resonance imaging every 3 months. Currently, chemoembolization is routinely performed in many centers instead of systemic chemotherapy for treating intrahepatic cholangiocellular carcinoma confined to the liver. Recently, radioembolization has been increasingly applied to cholangiocellular carcinoma as second line therapy after TACE failure or even as an alternative first line therapy. Nonetheless, no randomized studies have compared radioembolization and chemoembolization. Considering all this background information, we recognized a strong need for a randomized controlled trial (RCT) to compare the two treatments. Therefore, the present protocol describes the design of a RCT that compares SIRT and TACE as the first line therapy for inoperable CCC confined to the liver. ClinicalTrials.gov, Identifier: NCT01798147, registered 16th of February 2013.

Bilirubin and Stroke Risk Using a Mendelian Randomization Design.

PubMed

Lee, Sun Ju; Jee, Yon Ho; Jung, Keum Ji; Hong, Seri; Shin, Eun Soon; Jee, Sun Ha

2017-05-01

Circulating bilirubin, a natural antioxidant, is associated with decreased risk of stroke. However, the nature of the relationship between the two remains unknown. We used a Mendelian randomization analysis to assess the causal effect of serum bilirubin on stroke risk in Koreans. The 14 single-nucleotide polymorphisms (SNPs) (<10 -7 ) including rs6742078 of uridine diphosphoglucuronyl-transferase were selected from genome-wide association study of bilirubin level in the KCPS-II (Korean Cancer Prevention Study-II) Biobank subcohort consisting of 4793 healthy Korean and 806 stroke cases. Weighted genetic risk score was calculated using 14 SNPs selected from the top SNPs. Both rs6742078 (F statistics=138) and weighted genetic risk score with 14 SNPs (F statistics=187) were strongly associated with bilirubin levels. Simultaneously, serum bilirubin level was associated with decreased risk of stroke in an ordinary least-squares analysis. However, in 2-stage least-squares Mendelian randomization analysis, no causal relationship between serum bilirubin and stroke risk was found. There is no evidence that bilirubin level is causally associated with risk of stroke in Koreans. Therefore, bilirubin level is not a risk determinant of stroke. © 2017 American Heart Association, Inc.

Knowledge, attitude, and practice (KAP) of food hygiene among schools students' in Majmaah city, Saudi Arabia.

PubMed

Almansour, Mohammed; Sami, Waqas; Al-Rashedy, Oliyan Shoqer; Alsaab, Rayan Saad; Alfayez, Abdulrahman Saad; Almarri, Nawaf Rashed

2016-04-01

To determine the level of knowledge, attitude, and practice of food hygiene among primary, intermediate and high school students and explore association, if any, with socio-demographic differences. The observational cross-sectional study was conducted at boy's schools in Majmaah, Kingdom of Saudi Arabia, from February to May 2014. Data was collected using stratified random sampling technique from students aged 8-25 year. Two schools from each level (primary, intermediate and high school) were randomly selected and data was collected from the selected schools using simple random sampling method. A self-administered modified Sharif and Al-Malki questionnaire for knowledge, attitude and practice of food hygiene was used with Arabic translation. The mean age of 377 male students in the study was 14.53±2.647 years. Knowledge levels was less in primary school students compared to high school students (p=0.026). Attitude level was high in primary school students compared to intermediate school students (p< 0.001). No significant difference was observed between groups with regard to practice levels (p=0.152). The students exhibited good practice levels, despite fair knowledge and attitude levels.

Clinical and Health Outcomes Initiative in Comparative Effectiveness for Bipolar Disorder (Bipolar CHOICE): a pragmatic trial of complex treatment for a complex disorder.

PubMed

Nierenberg, Andrew A; Sylvia, Louisa G; Leon, Andrew C; Reilly-Harrington, Noreen A; Shesler, Leah W; McElroy, Susan L; Friedman, Edward S; Thase, Michael E; Shelton, Richard C; Bowden, Charles L; Tohen, Mauricio; Singh, Vivek; Deckersbach, Thilo; Ketter, Terence A; Kocsis, James H; McInnis, Melvin G; Schoenfeld, David; Bobo, William V; Calabrese, Joseph R

2014-02-01

Classic and second-generation antipsychotic mood stabilizers are recommended for treatment of bipolar disorder, yet there are no randomized comparative effectiveness studies that have examined the 'real-world' advantages and disadvantages of these medications. We describe the strategic decisions in the design of the Clinical and Health Outcomes Initiative in Comparative Effectiveness for Bipolar Disorder (Bipolar CHOICE). This article outlines the key issues and solutions the investigators faced in designing a clinical trial that would maximize generalizability and inform real-world clinical treatment of bipolar disorder. Bipolar CHOICE was a 6-month, multi-site, prospective, randomized clinical trial of outpatients with bipolar disorder. This study compares the effectiveness of quetiapine versus lithium, each with adjunctive personalized treatments (APTs). The co-primary outcomes selected are the overall benefits and harms of the study medications (as measured by the Clinical Global Impression-Efficacy Index) and the Necessary Clinical Adjustments (a measure of the number of medication changes). Secondary outcomes are continuous measures of mood, the Framingham General Cardiovascular Risk Score, and the Longitudinal Interval Follow up Evaluation Range of Impaired Functioning Tool (LIFE-RIFT). The final study design consisted of a single-blind, randomized comparative effectiveness trial of quetiapine versus lithium, plus APT, across 10 sites. Other important study considerations included limited exclusion criteria to maximize generalizability, flexible dosing of APT medications to mimic real-world treatment, and an intent-to-treat analysis plan. In all, 482 participants were randomized to the study, and 364 completed the study. The potential limitations of the study include the heterogeneity of APT, selection of study medications, lack of a placebo-control group, and participants' ability to pay for study medications. We expect that this study will inform our understanding of the benefits and harms of lithium, a classic mood stabilizer, compared to quetiapine, a second-generation antipsychotic with broad-spectrum activity in bipolar disorder, and will provide an example of a well-designed and well-conducted randomized comparative effectiveness clinical trial.

Sample size determination for bibliographic retrieval studies

PubMed Central

Yao, Xiaomei; Wilczynski, Nancy L; Walter, Stephen D; Haynes, R Brian

2008-01-01

Background Research for developing search strategies to retrieve high-quality clinical journal articles from MEDLINE is expensive and time-consuming. The objective of this study was to determine the minimal number of high-quality articles in a journal subset that would need to be hand-searched to update or create new MEDLINE search strategies for treatment, diagnosis, and prognosis studies. Methods The desired width of the 95% confidence intervals (W) for the lowest sensitivity among existing search strategies was used to calculate the number of high-quality articles needed to reliably update search strategies. New search strategies were derived in journal subsets formed by 2 approaches: random sampling of journals and top journals (having the most high-quality articles). The new strategies were tested in both the original large journal database and in a low-yielding journal (having few high-quality articles) subset. Results For treatment studies, if W was 10% or less for the lowest sensitivity among our existing search strategies, a subset of 15 randomly selected journals or 2 top journals were adequate for updating search strategies, based on each approach having at least 99 high-quality articles. The new strategies derived in 15 randomly selected journals or 2 top journals performed well in the original large journal database. Nevertheless, the new search strategies developed using the random sampling approach performed better than those developed using the top journal approach in a low-yielding journal subset. For studies of diagnosis and prognosis, no journal subset had enough high-quality articles to achieve the expected W (10%). Conclusion The approach of randomly sampling a small subset of journals that includes sufficient high-quality articles is an efficient way to update or create search strategies for high-quality articles on therapy in MEDLINE. The concentrations of diagnosis and prognosis articles are too low for this approach. PMID:18823538

Impact of Probiotics on Necrotizing Enterocolitis

PubMed Central

Underwood, Mark A.

2016-01-01

A large number of randomized placebo-controlled clinical trials and cohort studies have demonstrated a decrease in the incidence of necrotizing enterocolitis with administration of probiotic microbes. These studies have prompted many neonatologists to adopt routine prophylactic administration of probiotics while others await more definitive studies and/or probiotic products with demonstrated purity and stable numbers of live organisms. Cross-contamination and inadequate sample size limit the value of further traditional placebo-controlled randomized controlled trials. Key areas for future research include mechanisms of protection, optimum probiotic species or strains (or combinations thereof) and duration of treatment, interactions between diet and the administered probiotic, and the influence of genetic polymorphisms in the mother and infant on probiotic response. Next generation probiotics selected based on bacterial genetics rather than ease of production and large cluster-randomized clinical trials hold great promise for NEC prevention. PMID:27836423

76 FR 66051 - Notice of Submission for OMB Review

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-25

... have no identified disability, (2) youth who do not have an IEP but who have a condition that qualifies... cohorts of youth with an IEP who were studied in the past. Districts and youth will be randomly selected...

Reading Success and Failure among Chinese Children.

ERIC Educational Resources Information Center

Hsu, Chen-chin

Drawing on a cross-national study of children's reading, a study examined the correlates of reading success and failure in Taiwan. Subjects, 240 randomly selected Taipei fifth graders, were administered a reading test, cognitive test, and mathematics achievement test. A structured interview with each child's mother and classroom behavior…

Severity of Organized Item Theft in Computerized Adaptive Testing: A Simulation Study

ERIC Educational Resources Information Center

Yi, Qing; Zhang, Jinming; Chang, Hua-Hua

2008-01-01

Criteria had been proposed for assessing the severity of possible test security violations for computerized tests with high-stakes outcomes. However, these criteria resulted from theoretical derivations that assumed uniformly randomized item selection. This study investigated potential damage caused by organized item theft in computerized adaptive…

Factors Associated with Abnormal Eating Attitudes among Greek Adolescents

ERIC Educational Resources Information Center

Bilali, Aggeliki; Galanis, Petros; Velonakis, Emmanuel; Katostaras, Theofanis

2010-01-01

Objective: To estimate the prevalence of abnormal eating attitudes among Greek adolescents and identify possible risk factors associated with these attitudes. Design: Cross-sectional, school-based study. Setting: Six randomly selected schools in Patras, southern Greece. Participants: The study population consisted of 540 Greek students aged 13-18…

Drills vs. Games--Any Differences? A Pilot Study.

ERIC Educational Resources Information Center

McMullen, David W.

This study investigated the effect of informational, drill, and game format computer-assisted instruction (CAI) on the achievement, retention, and attitude toward instruction of sixth-grade science students (N=37). An informational CAI lesson on Halley's Comet was administered to three randomly selected groups of sixth-grade students. A CAI drill…

Women in University Management: The Nigerian Experience

ERIC Educational Resources Information Center

Abiodun-Oyebanji, Olayemi; Olaleye, F.

2011-01-01

This study examined women in university management in Nigeria. It was a descriptive research of the survey type. The population of the study comprised all the public universities in southwest Nigeria, out of which three were selected through the stratified random sampling technique. Three hundred respondents who were in management positions were…

The Effect of Preschool Education on Math Achievement.

ERIC Educational Resources Information Center

Vondrak, Maripatricia

A study examined the effects of preschool attendance on third graders' mathematics achievement. The subjects for the study were randomly selected from 111 third graders from a predominantly low socioeconomic neighborhood in Chicago. All students were from minority groups. The experimental group was comprised of 21 students who had attended…

Negative Particles and Morphemes in Jordanian Arabic Dialects

ERIC Educational Resources Information Center

Mrayat, Ahmad

2015-01-01

This paper aims at investigating the negative particles and morphemes in three main Jordanian dialects (Urban, Rural and Bedouin). This quantitative and qualitative study includes 30 teachers from different disciplines who use these dialects. The sample of the study was selected randomly. The research used two research instruments, a checklist and…

School Psychologist Diagnostic Decision-Making: A Pilot Study

ERIC Educational Resources Information Center

Barnard-Brak, Lucy; Stevens, Tara; Robinson, Eric; Holt, Ann

2013-01-01

The current study examined the diagnostic decision-making of school psychologists as a function of a student's disability and academic performance with three research questions using a randomly-selected sample of school psychologists from the state of Texas. Results from the first research question indicated that school psychologists significantly…

Children's Ability to Comprehend Main Ideas After Reading Expository Prose.

ERIC Educational Resources Information Center

Baumann, James F.

A study was conducted to evaluate children's ability to comprehend main ideas after reading connected discourse and to develop and validate a straightforward and intuitively simple system for identifying main ideas in prose. Three experimental passages were randomly selected from third and sixth grade social studies textbooks, and education…

Authentic Leadership and Altruism: The Mediating Role of Meaningfulness

ERIC Educational Resources Information Center

Sagnak, Mesut; Kuruöz, Mehmet

2017-01-01

The purpose of this study was to investigate the mediating effects of meaningfulness on the relationship between authentic leadership and altruistic behavior. The participants consisted of 356 teachers randomly selected from 14 primary and secondary schools in Nigde. Three different instruments were used in this study. The scales were translated…

Excellent Teachers' Thinking Model: Implications for Effective Teaching

ERIC Educational Resources Information Center

Hamzah, Sahandri G.; Mohamad, Hapidah; Ghorbani, Mohammad R.

2008-01-01

This study aimed to suggest an Excellent Teacher Thinking Model that has the potential to be utilized in the development of excellent teachers. Interaction survey method using survey questions, observation, document review and interview was conducted in this study. One hundred and five excellent teachers were selected randomly as research…

Mindful Listening Instruction: Does It Make a Difference

ERIC Educational Resources Information Center

Anderson, William Todd

2013-01-01

This study examines the effect of mindfulness on student listening. Mindfulness is defined as "the process of noticing novel distinctions." Fifth grade students (N = 38) at a single school participated in this study, which used a posttest-only, random selection experimental design. The Independent Variable was exposure to mindful…

Public Opinion toward Sexuality Education: Findings among One South Florida County

ERIC Educational Resources Information Center

Howard-Barr, Elissa; Moore, Michele Johnson; Weiss, Josie A.; Jobli, Edessa

2011-01-01

As part of a community plan to implement abstinence-based sexuality education, this study assessed opinions toward sexuality education among residents. Respondents (N = 1,090) were selected by random digit dialing. The survey, adopted from previous national studies, assessed attitudes towards sexuality education. Chi-square tests of significance…

Some Communication Effects of Charity Advertising Campaigns.

ERIC Educational Resources Information Center

Moore, Roy L.; And Others

A study was conducted to examine the relationship of advertising exposure to a variety of cognitive and affective variables in a nonprofit charity campaign. The study also tested the transactional model of advertising effects, which combines exposure, motivations, and gratifications for viewing. A sample of 350 adults was randomly selected and…

The 15-Second Television Commercial: A Study of Executive Perception.

ERIC Educational Resources Information Center

Asahina, Roberta R.

An exploratory study examined the perceptions of creative directors and broadcast production managers in advertising agencies regarding the perceived effects of the 15-second commercial upon creative formats and production techniques. A sample of 600 randomly selected advertising executives and managers were surveyed using a 55-item mailed…

An Improvement in Instructional Quality: Can Evaluation of Teaching Effectiveness Make a Difference?

ERIC Educational Resources Information Center

Ngware, Moses Waithanji; Ndirangu, Mwangi

2005-01-01

Purpose: To report study findings on teaching effectiveness and feedback mechanisms in Kenyan universities, which can guide management in developing a comprehensive quality control policy. Design/methodology/approach: The study adopted an exploratory descriptive design. Three public and two private universities were randomly selected to…

"Congratulations, you have been randomized into the control group!(?)": issues to consider when recruiting schools for matched-pair randomized control trials of prevention programs.

PubMed

Ji, Peter; DuBois, David L; Flay, Brian R; Brechling, Vanessa

2008-03-01

Recruiting schools into a matched-pair randomized control trial (MP-RCT) to evaluate the efficacy of a school-level prevention program presents challenges for researchers. We considered which of 2 procedures would be most effective for recruiting schools into the study and assigning them to conditions. In 1 procedure (recruit and match/randomize), we would recruit schools and match them prior to randomization, and in the other (match/randomize and recruitment), we would match schools and randomize them prior to recruitment. We considered how each procedure impacted the randomization process and our ability to recruit schools into the study. After implementing the selected procedure, the equivalence of both treatment and control group schools and the participating and nonparticipating schools on school demographic variables was evaluated. We decided on the recruit and match/randomize procedure because we thought it would provide the opportunity to build rapport with the schools and prepare them for the randomization process, thereby increasing the likelihood that they would accept their randomly assigned conditions. Neither the treatment and control group schools nor the participating and nonparticipating schools exhibited statistically significant differences from each other on any of the school demographic variables. Recruitment of schools prior to matching and randomization in an MP-RCT may facilitate the recruitment of schools and thus enhance both the statistical power and the representativeness of study findings. Future research would benefit from the consideration of a broader range of variables (eg, readiness to implement a comprehensive prevention program) both in matching schools and in evaluating their representativeness to nonparticipating schools.

Cumulative Evidence of Randomized Controlled and Observational Studies on Catheter-Related Infection Risk of Central Venous Catheter Insertion Site in ICU Patients: A Pairwise and Network Meta-Analysis.

PubMed

Arvaniti, Kostoula; Lathyris, Dimitrios; Blot, Stijn; Apostolidou-Kiouti, Fani; Koulenti, Despoina; Haidich, Anna-Bettina

2017-04-01

Selection of central venous catheter insertion site in ICU patients could help reduce catheter-related infections. Although subclavian was considered the most appropriate site, its preferential use in ICU patients is not generalized and questioned by contradicted meta-analysis results. In addition, conflicting data exist on alternative site selection whenever subclavian is contraindicated. To compare catheter-related bloodstream infection and colonization risk between the three sites (subclavian, internal jugular, and femoral) in adult ICU patients. We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled trials, CINAHL, and ClinicalTrials.gov. Eligible studies were randomized controlled trials and observational ones. Extracted data were analyzed by pairwise and network meta-analysis. Twenty studies were included; 11 were observational, seven were randomized controlled trials for other outcomes, and two were randomized controlled trials for sites. We evaluated 18,554 central venous catheters: 9,331 from observational studies, 5,482 from randomized controlled trials for other outcomes, and 3,741 from randomized controlled trials for sites. Colonization risk was higher for internal jugular (relative risk, 2.25 [95% CI, 1.84-2.75]; I = 0%) and femoral (relative risk, 2.92 [95% CI, 2.11-4.04]; I = 24%), compared with subclavian. Catheter-related bloodstream infection risk was comparable for internal jugular and subclavian, higher for femoral than subclavian (relative risk, 2.44 [95% CI, 1.25-4.75]; I = 61%), and lower for internal jugular than femoral (relative risk, 0.55 [95% CI, 0.34-0.89]; I = 61%). When observational studies that did not control for baseline characteristics were excluded, catheter-related bloodstream infection risk was comparable between the sites. In ICU patients, internal jugular and subclavian may, similarly, decrease catheter-related bloodstream infection risk, when compared with femoral. Subclavian could be suggested as the most appropriate site, whenever colonization risk is considered and not, otherwise, contraindicated. Current evidence on catheter-related bloodstream infection femoral risk, compared with the other sites, is inconclusive.

Developing Academic Motivation Scale for Learning Information Technology (AMSLIT): A Study of Validity and Reliability

ERIC Educational Resources Information Center

Schreglmann, Sinan

2018-01-01

This study aimed to develop Academic Motivation Scale for Learning Information Technology for university students. For this purpose, 120 randomly selected university students studying in different classes and faculties at KSU were invited to the study during the 2016-2017 academic year. To define the scale indicators students were asked to answer…

Effect of anger management education on mental health and aggression of prisoner women.

PubMed

Bahrami, Elaheh; Mazaheri, Maryam Amidi; Hasanzadeh, Akbar

2016-01-01

"Uncontrolled anger" threats the compatible and health of people as serious risk. The effects of weaknesses and shortcomings in the management of anger, from personal distress and destruction interpersonal relationships beyond and linked to the public health problems, lack of compromises, and aggressive behavior adverse outcomes. This study investigates the effects of anger management education on mental health and aggression of prisoner women in Isfahan. The single-group quasi-experimental (pretest, posttest) by prisoner women in the central prison of Isfahan was done. Multi-stage random sampling method was used. Initially, 165 women were selected randomly and completed the Buss and Perry Aggression Questionnaire and the General Health Questionnaire-28, and among these, those with scores >78 (the cut point) in aggression scale was selected and among them 70 were randomly selected. In the next step, interventions in four 90 min training sessions were conducted. Posttest was performed within 1-month after the intervention. Data were analyzed using SPSS-20 software. Data analysis showed that anger management training was effective in reducing aggression (P < 0.001) and also had a positive effect on mental health (P < 0.001). According to the importance of aggression in consistency and individual and collective health and according to findings, presented educational programs on anger management is essential for female prisoners.

Varying levels of difficulty index of skills-test items randomly selected by examinees on the Korean emergency medical technician licensing examination.

PubMed

Koh, Bongyeun; Hong, Sunggi; Kim, Soon-Sim; Hyun, Jin-Sook; Baek, Milye; Moon, Jundong; Kwon, Hayran; Kim, Gyoungyong; Min, Seonggi; Kang, Gu-Hyun

2016-01-01

The goal of this study was to characterize the difficulty index of the items in the skills test components of the class I and II Korean emergency medical technician licensing examination (KEMTLE), which requires examinees to select items randomly. The results of 1,309 class I KEMTLE examinations and 1,801 class II KEMTLE examinations in 2013 were subjected to analysis. Items from the basic and advanced skills test sections of the KEMTLE were compared to determine whether some were significantly more difficult than others. In the class I KEMTLE, all 4 of the items on the basic skills test showed significant variation in difficulty index (P<0.01), as well as 4 of the 5 items on the advanced skills test (P<0.05). In the class II KEMTLE, 4 of the 5 items on the basic skills test showed significantly different difficulty index (P<0.01), as well as all 3 of the advanced skills test items (P<0.01). In the skills test components of the class I and II KEMTLE, the procedure in which examinees randomly select questions should be revised to require examinees to respond to a set of fixed items in order to improve the reliability of the national licensing examination.

Clinical Health Outcomes Initiative in Comparative Effectiveness for Bipolar Disorder (Bipolar CHOICE): A Pragmatic Trial of Complex Treatment for a Complex Disorder

PubMed Central

Nierenberg, Andrew A.; Sylvia, Louisa G.; Leon, Andrew C.; Reilly-Harrington, Noreen; Shesler, Leah W.; McElroy, Susan L.; Friedman, Edward S.; Thase, Michael E.; Shelton, Richard C.; Bowden, Charles; Tohen, Mauricio; Singh, Vivek; Deckersbach, Thilo; Ketter, Terence; Kocsis, James; McInnis, Melvin G.; Schoenfeld, David; Bobo, William V.; Calabrese, Joseph R.

2015-01-01

Background Classic and second generation antipsychotic mood stabilizers are recommended for treatment of bipolar disorder, yet there are no randomized comparative effectiveness studies that have examined the “real-world” advantages and disadvantages of these medications Purpose We describe the strategic decisions in the design of the Clinical and Health Outcomes Initiative in Comparative Effectiveness for Bipolar Disorder (Bipolar CHOICE). This paper outlines the key issues and solutions the investigators faced in designing a clinical trial that would maximize generalizability and inform real-world clinical treatment of bipolar disorder. Methods Bipolar CHOICE was a 6-month, multi-site, prospective, randomized clinical trial of outpatients with bipolar disorder. This study compares the effectiveness of quetiapine versus lithium, each with adjunctive personalized treatments. The co-primary outcomes selected are the overall benefits and harms of the study medications (as measured by the Clinical Global Impression-Efficacy Index) and the Necessary Clinical Adjustments (a measure of the number of medication changes). Secondary outcomes are continuous measures of mood, the Framingham General Cardiovascular Risk Score and the Longitudinal Interval Follow up Evaluation Range of Impaired Functioning Tool. Results The final study design consisted of a single-blind, randomized comparative effectiveness trial of quetiapine versus lithium, plus adjunctive personalized treatment (APT), across ten sites. Other important study considerations included limited exclusion criteria to maximize generalizability, flexible dosing of APT medications to mimic real-world treatment, and an intent-to-treat analysis plan. 482 participants were randomized to the study and 364 completed. Limitations The potential limitations of the study include the heterogeneity of APT, selection of study medications, lack of a placebo-control group, and participants’ ability to pay for study medications. Conclusion We expect that this study will inform our understanding of the benefits and harms of lithium, a classic mood stabilizer, compared to quetiapine, a second generation antipsychotic with broad-spectrum activity in bipolar disorder and will provide an example of a well-designed and well-conducted randomized comparative effectiveness clinical trial. PMID:24346608

Quality of surgical randomized controlled trials for acute cholecystitis: assessment based on CONSORT and additional check items.

PubMed

Shikata, Satoru; Nakayama, Takeo; Yamagishi, Hisakazu

2008-01-01

In this study, we conducted a limited survey of reports of surgical randomized controlled trials, using the consolidated standards of reporting trials (CONSORT) statement and additional check items to clarify problems in the evaluation of surgical reports. A total of 13 randomized trials were selected from two latest review articles on biliary surgery. Each randomized trial was evaluated according to 28 quality measures that comprised items from the CONSORT statement plus additional items. Analysis focused on relationships between the quality of each study and the estimated effect gap ("pooled estimate in meta-analysis" -- "estimated effect of each study"). No definite relationships were found between individual study quality and the estimated effect gap. The following items could have been described but were not provided in almost all the surgical RCT reports: "clearly defined outcomes"; "details of randomization"; "participant flow charts"; "intention-to-treat analysis"; "ancillary analyses"; and "financial conflicts of interest". The item, "participation of a trial methodologist in the study" was not found in any of the reports. Although the quality of reporting trials is not always related to a biased estimation of treatment effect, the items used for quality measures must be described to enable readers to evaluate the quality and applicability of the reporting. Further development of an assessment tool is needed for items specific to surgical randomized controlled trials.

Surgical treatment of hepatocellular carcinoma: evidence-based outcomes.

PubMed

Yamazaki, Shintaro; Takayama, Tadatoshi

2008-02-07

Surgeons may be severely criticized from the perspective of evidence-based medicine because the majority of surgical publications appear not to be convincing. In the top nine surgical journals in 1996, half of the 175 publications refer to pilot studies lacking a control group, 18% to animal experiments, and only 5% to randomized controlled trials (RCT). There are five levels of clinical evidence: level 1 (randomized controlled trial), level 2 (prospective concurrent cohort study), level 3 (retrospective historical cohort study), level 4 (pre-post study), and level 5 (case report). Recently, a Japanese evidence-based guideline for the surgical treatment of hepatocellular carcinoma (HCC) was made by a committee (Chairman, Professor Makuuchi and five members). We searched the literature using the Medline Dialog System with four keywords: HCC, surgery, English papers, in the last 20 years. A total of 915 publications were identified systematically reviewed. At the first selection (in which surgery-dominant papers were selected), 478 papers survived. In the second selection (clearly concluded papers), 181 papers survived. In the final selection (clinically significant papers), 100 papers survived. The evidence level of the 100 surviving papers is shown here: level-1 papers (13%), level-2 papers (11%), level-3 papers (52%), and level-4 papers (24%); therefore, there were 24% prospective papers and 76% retrospective papers. Here, we present a part of the guideline on the five main surgical issues: indication to operation, operative procedure, peri-operative care, prognostic factor, and post-operative adjuvant therapy.

Surgical treatment of hepatocellular carcinoma: Evidence-based outcomes

PubMed Central

Yamazaki, Shintaro; Takayama, Tadatoshi

2008-01-01

Surgeons may be severely criticized from the perspective of evidence-based medicine because the majority of surgical publications appear not to be convincing. In the top nine surgical journals in 1996, half of the 175 publications refer to pilot studies lacking a control group, 18% to animal experiments, and only 5% to randomized controlled trials (RCT). There are five levels of clinical evidence: level 1 (randomized controlled trial), level 2 (prospective concurrent cohort study), level 3 (retrospective historical cohort study), level 4 (pre-post study), and level 5 (case report). Recently, a Japanese evidence-based guideline for the surgical treatment of hepatocellular carcinoma (HCC) was made by a committee (Chairman, Professor Makuuchi and five members). We searched the literature using the Medline Dialog System with four keywords: HCC, surgery, English papers, in the last 20 years. A total of 915 publications were identified systematically reviewed. At the first selection (in which surgery-dominant papers were selected), 478 papers survived. In the second selection (clearly concluded papers), 181 papers survived. In the final selection (clinically significant papers), 100 papers survived. The evidence level of the 100 surviving papers is shown here: level-1 papers (13%), level-2 papers (11%), level-3 papers (52%), and level-4 papers (24%); therefore, there were 24% prospective papers and 76% retrospective papers. Here, we present a part of the guideline on the five main surgical issues: indication to operation, operative procedure, peri-operative care, prognostic factor, and post-operative adjuvant therapy. PMID:18205256

Meta-analysis of diagnostic accuracy studies accounting for disease prevalence: alternative parameterizations and model selection.

PubMed

Chu, Haitao; Nie, Lei; Cole, Stephen R; Poole, Charles

2009-08-15

In a meta-analysis of diagnostic accuracy studies, the sensitivities and specificities of a diagnostic test may depend on the disease prevalence since the severity and definition of disease may differ from study to study due to the design and the population considered. In this paper, we extend the bivariate nonlinear random effects model on sensitivities and specificities to jointly model the disease prevalence, sensitivities and specificities using trivariate nonlinear random-effects models. Furthermore, as an alternative parameterization, we also propose jointly modeling the test prevalence and the predictive values, which reflect the clinical utility of a diagnostic test. These models allow investigators to study the complex relationship among the disease prevalence, sensitivities and specificities; or among test prevalence and the predictive values, which can reveal hidden information about test performance. We illustrate the proposed two approaches by reanalyzing the data from a meta-analysis of radiological evaluation of lymph node metastases in patients with cervical cancer and a simulation study. The latter illustrates the importance of carefully choosing an appropriate normality assumption for the disease prevalence, sensitivities and specificities, or the test prevalence and the predictive values. In practice, it is recommended to use model selection techniques to identify a best-fitting model for making statistical inference. In summary, the proposed trivariate random effects models are novel and can be very useful in practice for meta-analysis of diagnostic accuracy studies. Copyright 2009 John Wiley & Sons, Ltd.

A management-oriented classification of pinyon-juniper woodlands of the Great Basin

Treesearch

Neil E. West; Robin J. Tausch; Paul T. Tueller

1998-01-01

A hierarchical framework for the classification of Great Basin pinyon-juniper woodlands was based on a systematic sample of 426 stands from a random selection of 66 of the 110 mountain ranges in the region. That is, mountain ranges were randomly selected, but stands were systematically located on mountain ranges. The National Hierarchical Framework of Ecological Units...

School Happiness and School Success: An Investigation across Multiple Grade Levels.

ERIC Educational Resources Information Center

Parish, Joycelyn Gay; Parish, Thomas S.; Batt, Steve

A total of 572 randomly selected sixth-grade students and 908 randomly selected ninth-grade students from a large metropolitan school district in the Midwest were asked to complete a series of survey questions designed to measure the extent to which they were happy while at school, as well as questions concerning the extent to which they treated…

40 CFR 761.306 - Sampling 1 meter square surfaces by random selection of halves.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Sampling 1 meter square surfaces by...(b)(3) § 761.306 Sampling 1 meter square surfaces by random selection of halves. (a) Divide each 1 meter square portion where it is necessary to collect a surface wipe test sample into two equal (or as...

40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

Code of Federal Regulations, 2013 CFR

2013-07-01

... generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square grid. (a) Divide the surface area of the non-porous surface into rectangular or square areas having a...

40 CFR 761.306 - Sampling 1 meter square surfaces by random selection of halves.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Sampling 1 meter square surfaces by...(b)(3) § 761.306 Sampling 1 meter square surfaces by random selection of halves. (a) Divide each 1 meter square portion where it is necessary to collect a surface wipe test sample into two equal (or as...

40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

Code of Federal Regulations, 2011 CFR

2011-07-01

... generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square grid. (a) Divide the surface area of the non-porous surface into rectangular or square areas having a...

40 CFR 761.306 - Sampling 1 meter square surfaces by random selection of halves.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Sampling 1 meter square surfaces by...(b)(3) § 761.306 Sampling 1 meter square surfaces by random selection of halves. (a) Divide each 1 meter square portion where it is necessary to collect a surface wipe test sample into two equal (or as...

40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

Code of Federal Regulations, 2010 CFR

2010-07-01

... generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square grid. (a) Divide the surface area of the non-porous surface into rectangular or square areas having a...

40 CFR 761.306 - Sampling 1 meter square surfaces by random selection of halves.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Sampling 1 meter square surfaces by...(b)(3) § 761.306 Sampling 1 meter square surfaces by random selection of halves. (a) Divide each 1 meter square portion where it is necessary to collect a surface wipe test sample into two equal (or as...

40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

Code of Federal Regulations, 2014 CFR

2014-07-01

... generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square grid. (a) Divide the surface area of the non-porous surface into rectangular or square areas having a...

40 CFR 761.306 - Sampling 1 meter square surfaces by random selection of halves.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sampling 1 meter square surfaces by...(b)(3) § 761.306 Sampling 1 meter square surfaces by random selection of halves. (a) Divide each 1 meter square portion where it is necessary to collect a surface wipe test sample into two equal (or as...

40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

Code of Federal Regulations, 2012 CFR

2012-07-01

... generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square grid. (a) Divide the surface area of the non-porous surface into rectangular or square areas having a...

Deterministic chaotic dynamics of Raba River flow (Polish Carpathian Mountains)

NASA Astrophysics Data System (ADS)

Kędra, Mariola

2014-02-01

Is the underlying dynamics of river flow random or deterministic? If it is deterministic, is it deterministic chaotic? This issue is still controversial. The application of several independent methods, techniques and tools for studying daily river flow data gives consistent, reliable and clear-cut results to the question. The outcomes point out that the investigated discharge dynamics is not random but deterministic. Moreover, the results completely confirm the nonlinear deterministic chaotic nature of the studied process. The research was conducted on daily discharge from two selected gauging stations of the mountain river in southern Poland, the Raba River.

Use of Random and Site-Directed Mutagenesis to Probe Protein Structure-Function Relationships: Applied Techniques in the Study of Helicobacter pylori.

PubMed

Whitmire, Jeannette M; Merrell, D Scott

2017-01-01

Mutagenesis is a valuable tool to examine the structure-function relationships of bacterial proteins. As such, a wide variety of mutagenesis techniques and strategies have been developed. This chapter details a selection of random mutagenesis methods and site-directed mutagenesis procedures that can be applied to an array of bacterial species. Additionally, the direct application of the techniques to study the Helicobacter pylori Ferric Uptake Regulator (Fur) protein is described. The varied approaches illustrated herein allow the robust investigation of the structural-functional relationships within a protein of interest.

The applications of regenerative medicine in sinus lift procedures: A systematic review.

PubMed

Correia, Francisco; Pozza, Daniel Humberto; Gouveia, Sónia; Felino, António; Faria E Almeida, Ricardo

2018-04-01

Findings in regenerative medicine applied to the sinus lift procedures. Evaluate the effectiveness of regenerative medicine in sinus lift. An extensive search for manuscripts were performed by using different combinations of keywords and MeSH terms (Pub-med; Embase; Scopus; Web of Science Core Collection; Medline; Current Contents Connect; Derwent Innovations Index; Scielo Citation Index; Cochrane library). The full text selected articles are written in English, Portuguese, Spanish, Italian, German, or French, and published until 28 of November 2016. Inclusion criteria were: implant osteointegration, radiographic, histologic, and/or histomorphometric analysis, clinical studies in humans using of regenerative medicine. This systematic review was performed by selecting only randomized controlled clinical trials and controlled clinical trials. Eighteen published studies (11 CT and 7 RCT) were considered eligible for inclusion in the present systematic review. These studies demonstrated considerable variation of biomaterial and cell technics used, study design, sinus lift technic, outcomes, follow-up, and results. Only few studies have demonstrated potential of regenerative medicine in sinus lift; further randomized clinical trials are needed to achieve more accurate results. © 2017 Wiley Periodicals, Inc.

Vast Portfolio Selection with Gross-exposure Constraints*

PubMed Central

Fan, Jianqing; Zhang, Jingjin; Yu, Ke

2012-01-01

We introduce the large portfolio selection using gross-exposure constraints. We show that with gross-exposure constraint the empirically selected optimal portfolios based on estimated covariance matrices have similar performance to the theoretical optimal ones and there is no error accumulation effect from estimation of vast covariance matrices. This gives theoretical justification to the empirical results in Jagannathan and Ma (2003). We also show that the no-short-sale portfolio can be improved by allowing some short positions. The applications to portfolio selection, tracking, and improvements are also addressed. The utility of our new approach is illustrated by simulation and empirical studies on the 100 Fama-French industrial portfolios and the 600 stocks randomly selected from Russell 3000. PMID:23293404

Improved Compressive Sensing of Natural Scenes Using Localized Random Sampling

PubMed Central

Barranca, Victor J.; Kovačič, Gregor; Zhou, Douglas; Cai, David

2016-01-01

Compressive sensing (CS) theory demonstrates that by using uniformly-random sampling, rather than uniformly-spaced sampling, higher quality image reconstructions are often achievable. Considering that the structure of sampling protocols has such a profound impact on the quality of image reconstructions, we formulate a new sampling scheme motivated by physiological receptive field structure, localized random sampling, which yields significantly improved CS image reconstructions. For each set of localized image measurements, our sampling method first randomly selects an image pixel and then measures its nearby pixels with probability depending on their distance from the initially selected pixel. We compare the uniformly-random and localized random sampling methods over a large space of sampling parameters, and show that, for the optimal parameter choices, higher quality image reconstructions can be consistently obtained by using localized random sampling. In addition, we argue that the localized random CS optimal parameter choice is stable with respect to diverse natural images, and scales with the number of samples used for reconstruction. We expect that the localized random sampling protocol helps to explain the evolutionarily advantageous nature of receptive field structure in visual systems and suggests several future research areas in CS theory and its application to brain imaging. PMID:27555464

Optimized bioregenerative space diet selection with crew choice

NASA Technical Reports Server (NTRS)

Vicens, Carrie; Wang, Carolyn; Olabi, Ammar; Jackson, Peter; Hunter, Jean

2003-01-01

Previous studies on optimization of crew diets have not accounted for choice. A diet selection model with crew choice was developed. Scenario analyses were conducted to assess the feasibility and cost of certain crew preferences, such as preferences for numerous-desserts, high-salt, and high-acceptability foods. For comparison purposes, a no-choice and a random-choice scenario were considered. The model was found to be feasible in terms of food variety and overall costs. The numerous-desserts, high-acceptability, and random-choice scenarios all resulted in feasible solutions costing between 13.2 and 17.3 kg ESM/person-day. Only the high-sodium scenario yielded an infeasible solution. This occurred when the foods highest in salt content were selected for the crew-choice portion of the diet. This infeasibility can be avoided by limiting the total sodium content in the crew-choice portion of the diet. Cost savings were found by reducing food variety in scenarios where the preference bias strongly affected nutritional content.

Factual knowledge about AIDS and dating practices among high school students from selected schools.

PubMed

Nyachuru-Sihlangu, R H; Ndlovu, J

1992-06-01

Following various educational strategies by governmental and non-governmental organisations to educate youths and school teachers about HIV infection and prevention, this KABP survey was one attempt to evaluate the results. The study sample of 478 high school students was drawn from four randomly selected schools in Mashonaland and Matabeleland including high and low density, government and mission co-educational schools. The sample was randomly selected and stratified to represent sex and grade level. The KABP self administered questionnaire was used. The paper analyses the relationship between the knowledge and dating patterns. Generally, respondents demonstrated a 50pc to 80pc accuracy of factual knowledge. Of the 66pc Forms I through IV pupils who dated, 30pc preferred only sexually involved relationships and a small number considered the possibility of HIV/AIDS infection. A theoretically based tripartite coalition involving the school, the family health care services for education, guidance and support to promote responsible behaviour throughout childhood was suggested.

Attitude towards the Practice of Female Genital Cutting among School Boys and Girls in Somali and Harari Regions, Eastern Ethiopia

PubMed Central

2017-01-01

Introduction. Female genital cutting (FGC) is a harmful traditional practice that violates women's rights and threatens their health. Although much work has been done to tackle this practice in Ethiopia, the prevalence remains very high in Somali and Harari regions. This study aims to investigate the attitude towards FGC of young people (boys and girls) in Somali and Harari regions of Eastern Ethiopia. Methods. A cross-sectional quantitative study was carried out in Somali and Harari regions from October to December 2015. Two districts were purposely selected from the two regions, and a stratified random sampling technique was employed to select 480 subjects from the randomly selected schools. Results. Out of 480 questionnaires distributed, 478 (99.6%) respondents filled the questionnaires and returned them. The finding of the study reveals that 86% of study participants condemn the practice of FGC. Almost 59% of male participants from both study areas preferred to marry uncircumcised girls. Being a female and being a Muslim are significantly associated with the support toward the continuation of the FGC (P < 0.05). Conclusion. Although the study demonstrates a positive attitude towards the abandonment of FGC, there is a need to increase the knowledge about the position of Islam in FGC and to educate women about the harmful effect of FGC. PMID:28386281

Nest-site selection and reproductive success of greater sage-grouse in a fire-affected habitat of northwestern Nevada

USGS Publications Warehouse

Lockyer, Zachary B.; Coates, Peter S.; Casazza, Michael L.; Espinosa, Shawn; Delehanty, David J.

2015-01-01

Identifying links between micro-habitat selection and wildlife reproduction is imperative to population persistence and recovery. This information is particularly important for landscape species such as greater sage-grouse (Centrocercus urophasianus; sage-grouse). Although this species has been widely studied, because environmental factors can affect sage-grouse populations, local and regional studies are crucial for developing viable conservation strategies. We studied the habitat-use patterns of 71 radio-marked sage-grouse inhabiting an area affected by wildfire in the Virginia Mountains of northwestern Nevada during 2009–2011 to determine the effect of micro-habitat attributes on reproductive success. We measured standard vegetation parameters at nest and random sites using a multi-scale approach (range = 0.01–15,527 ha). We used an information-theoretic modeling approach to identify environmental factors influencing nest-site selection and survival, and determine whether nest survival was a function of resource selection. Sage-grouse selected micro-sites with greater shrub canopy cover and less cheatgrass (Bromus tectorum) cover than random sites. Total shrub canopy, including sagebrush (Artemisia spp.) and other shrub species, at small spatial scales (0.8 ha and 3.1 ha) was the single contributing selection factor to higher nest survival. These results indicate that reducing the risk of wildfire to maintain important sagebrush habitats could be emphasized in sage-grouse conservation strategies in Nevada. Managers may seek to mitigate the influx of annual grass invasion by preserving large intact sagebrush-dominated stands with a mixture of other shrub species. For this area of Nevada, the results suggest that ≥40% total shrub canopy cover in sage-grouse nesting areas could yield improved reproductive success. 

Large-scale randomized clinical trials of bioactives and nutrients in relation to human health and disease prevention - Lessons from the VITAL and COSMOS trials.

PubMed

Rautiainen, Susanne; Sesso, Howard D; Manson, JoAnn E

2017-12-29

Several bioactive compounds and nutrients in foods have physiological properties that are beneficial for human health. While nutrients typically have clear definitions with established levels of recommended intakes, bioactive compounds often lack such a definition. Although a food-based approach is often the optimal approach to ensure adequate intake of bioactives and nutrients, these components are also often produced as dietary supplements. However, many of these supplements are not sufficiently studied and have an unclear role in chronic disease prevention. Randomized trials are considered the gold standard of study designs, but have not been fully applied to understand the effects of bioactives and nutrients. We review the specific role of large-scale trials to test whether bioactives and nutrients have an effect on health outcomes through several crucial components of trial design, including selection of intervention, recruitment, compliance, outcome selection, and interpretation and generalizability of study findings. We will discuss these components in the context of two randomized clinical trials, the VITamin D and OmegA-3 TriaL (VITAL) and the COcoa Supplement and Multivitamin Outcomes Study (COSMOS). We will mainly focus on dietary supplements of bioactives and nutrients while also emphasizing the need for translation and integration with food-based trials that are of vital importance within nutritional research. Copyright © 2017. Published by Elsevier Ltd.

Selection of stable scFv antibodies by phage display.

PubMed

Brockmann, Eeva-Christine

2012-01-01

ScFv fragments are popular recombinant antibody formats but often suffer from limited stability. Phage display is a powerful tool in antibody engineering and applicable also for stability selection. ScFv variants with improved stability can be selected from large randomly mutated phage displayed libraries with a specific antigen after the unstable variants have been inactivated by heat or GdmCl. Irreversible scFv denaturation, which is a prerequisite for efficient selection, is achieved by combining denaturation with reduction of the intradomain disulfide bonds. Repeated selection cycles of increasing stringency result in enrichment of stabilized scFv fragments. Procedures for constructing a randomly mutated scFv library by error-prone PCR and phage display selection for enrichment of stable scFv antibodies from the library are described here.

Alternative Modal Basis Selection Procedures for Nonlinear Random Response Simulation

NASA Technical Reports Server (NTRS)

Przekop, Adam; Guo, Xinyun; Rizzi, Stephen A.

2010-01-01

Three procedures to guide selection of an efficient modal basis in a nonlinear random response analysis are examined. One method is based only on proper orthogonal decomposition, while the other two additionally involve smooth orthogonal decomposition. Acoustic random response problems are employed to assess the performance of the three modal basis selection approaches. A thermally post-buckled beam exhibiting snap-through behavior, a shallowly curved arch in the auto-parametric response regime and a plate structure are used as numerical test articles. The results of the three reduced-order analyses are compared with the results of the computationally taxing simulation in the physical degrees of freedom. For the cases considered, all three methods are shown to produce modal bases resulting in accurate and computationally efficient reduced-order nonlinear simulations.

An investigation into the probabilistic combination of quasi-static and random accelerations

NASA Technical Reports Server (NTRS)

Schock, R. W.; Tuell, L. P.

1984-01-01

The development of design load factors for aerospace and aircraft components and experiment support structures, which are subject to a simultaneous vehicle dynamic vibration (quasi-static) and acoustically generated random vibration, require the selection of a combination methodology. Typically, the procedure is to define the quasi-static and the random generated response separately, and arithmetically add or root sum square to get combined accelerations. Since the combination of a probabilistic and a deterministic function yield a probabilistic function, a viable alternate approach would be to determine the characteristics of the combined acceleration probability density function and select an appropriate percentile level for the combined acceleration. The following paper develops this mechanism and provides graphical data to select combined accelerations for most popular percentile levels.

Effects of Problem-Solving Method on Secondary School Students' Achievement and Retention in Social Studies, in Ekiti State, Nigeria

ERIC Educational Resources Information Center

Abdu-Raheem, B. O.

2012-01-01

This study investigated the effects of problem-solving method of teaching on secondary school students' achievement and retention in Social Studies. The study adopted the quasi-experimental, pre-test, post-test, control group design. The sample for the study consisted of 240 Junior Secondary School Class II students randomly selected from six…

Feasibility of quasi-random band model in evaluating atmospheric radiance

NASA Technical Reports Server (NTRS)

Tiwari, S. N.; Mirakhur, N.

1980-01-01

The use of the quasi-random band model in evaluating upwelling atmospheric radiation is investigated. The spectral transmittance and total band adsorptance are evaluated for selected molecular bands by using the line by line model, quasi-random band model, exponential sum fit method, and empirical correlations, and these are compared with the available experimental results. The atmospheric transmittance and upwelling radiance were calculated by using the line by line and quasi random band models and were compared with the results of an existing program called LOWTRAN. The results obtained by the exponential sum fit and empirical relations were not in good agreement with experimental results and their use cannot be justified for atmospheric studies. The line by line model was found to be the best model for atmospheric applications, but it is not practical because of high computational costs. The results of the quasi random band model compare well with the line by line and experimental results. The use of the quasi random band model is recommended for evaluation of the atmospheric radiation.

Neither fixed nor random: weighted least squares meta-analysis.

PubMed

Stanley, T D; Doucouliagos, Hristos

2015-06-15

This study challenges two core conventional meta-analysis methods: fixed effect and random effects. We show how and explain why an unrestricted weighted least squares estimator is superior to conventional random-effects meta-analysis when there is publication (or small-sample) bias and better than a fixed-effect weighted average if there is heterogeneity. Statistical theory and simulations of effect sizes, log odds ratios and regression coefficients demonstrate that this unrestricted weighted least squares estimator provides satisfactory estimates and confidence intervals that are comparable to random effects when there is no publication (or small-sample) bias and identical to fixed-effect meta-analysis when there is no heterogeneity. When there is publication selection bias, the unrestricted weighted least squares approach dominates random effects; when there is excess heterogeneity, it is clearly superior to fixed-effect meta-analysis. In practical applications, an unrestricted weighted least squares weighted average will often provide superior estimates to both conventional fixed and random effects. Copyright © 2015 John Wiley & Sons, Ltd.

Estimation of genetic parameters and breeding values across challenged environments to select for robust pigs.

PubMed

Herrero-Medrano, J M; Mathur, P K; ten Napel, J; Rashidi, H; Alexandri, P; Knol, E F; Mulder, H A

2015-04-01

Robustness is an important issue in the pig production industry. Since pigs from international breeding organizations have to withstand a variety of environmental challenges, selection of pigs with the inherent ability to sustain their productivity in diverse environments may be an economically feasible approach in the livestock industry. The objective of this study was to estimate genetic parameters and breeding values across different levels of environmental challenge load. The challenge load (CL) was estimated as the reduction in reproductive performance during different weeks of a year using 925,711 farrowing records from farms distributed worldwide. A wide range of levels of challenge, from favorable to unfavorable environments, was observed among farms with high CL values being associated with confirmed situations of unfavorable environment. Genetic parameters and breeding values were estimated in high- and low-challenge environments using a bivariate analysis, as well as across increasing levels of challenge with a random regression model using Legendre polynomials. Although heritability estimates of number of pigs born alive were slightly higher in environments with extreme CL than in those with intermediate levels of CL, the heritabilities of number of piglet losses increased progressively as CL increased. Genetic correlations among environments with different levels of CL suggest that selection in environments with extremes of low or high CL would result in low response to selection. Therefore, selection programs of breeding organizations that are commonly conducted under favorable environments could have low response to selection in commercial farms that have unfavorable environmental conditions. Sows that had experienced high levels of challenge at least once during their productive life were ranked according to their EBV. The selection of pigs using EBV ignoring environmental challenges or on the basis of records from only favorable environments resulted in a sharp decline in productivity as the level of challenge increased. In contrast, selection using the random regression approach resulted in limited change in productivity with increasing levels of challenge. Hence, we demonstrate that the use of a quantitative measure of environmental CL and a random regression approach can be comprehensively combined for genetic selection of pigs with enhanced ability to maintain high productivity in harsh environments.

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

Bromberger, Seth A.; Klymko, Christine F.; Henderson, Keith A.

Betweenness centrality is a graph statistic used to nd vertices that are participants in a large number of shortest paths in a graph. This centrality measure is commonly used in path and network interdiction problems and its complete form requires the calculation of all-pairs shortest paths for each vertex. This leads to a time complexity of O(jV jjEj), which is impractical for large graphs. Estimation of betweenness centrality has focused on performing shortest-path calculations on a subset of randomly- selected vertices. This reduces the complexity of the centrality estimation to O(jSjjEj); jSj < jV j, which can be scaled appropriatelymore » based on the computing resources available. An estimation strategy that uses random selection of vertices for seed selection is fast and simple to implement, but may not provide optimal estimation of betweenness centrality when the number of samples is constrained. Our experimentation has identi ed a number of alternate seed-selection strategies that provide lower error than random selection in common scale-free graphs. These strategies are discussed and experimental results are presented.« less

The Effect of Sodium Hypochlorite and Chlorhexidine as Irrigant Solutions for Root Canal Disinfection: A Systematic Review of Clinical Trials.

PubMed

Gonçalves, Lucio Souza; Rodrigues, Renata Costa Val; Andrade Junior, Carlos Vieira; Soares, Renata G; Vettore, Mario Vianna

2016-04-01

This systematic review aimed to compare the effectiveness of sodium hypochlorite and chlorhexidine for root canal disinfection during root canal therapy. A literature search for clinical trials was made on the PubMed (MEDLINE), Web of Knowledge, SCOPUS, and Science Direct databases and in the reference lists of the identified articles up to January 2015. Quality assessment of the selected studies was performed according to the Consolidated Standards of Reporting Trials statement. One clinical trial and 4 randomized clinical trials were selected from the 172 articles initially identified. There was heterogeneity in the laboratory methods used to assess the root canal disinfection as well as in the concentrations of the irrigants used. Therefore, meta-analysis was not performed. Two studies reported effective and similar reductions in bacterial levels for both irrigants. Sodium hypochlorite was more effective than chlorhexidine in reducing microorganisms in 1 study, and another reported opposite findings. Both root irrigants were ineffective in eliminating endotoxins from necrotic pulp root canals in 1 study. Trial design and information regarding randomization procedures were not clearly described in the clinical trials. No study compared laboratory results with clinical outcomes. The available evidence on this topic is scarce, and the findings of studies were not consistent. Additional randomized clinical trials using clinical outcomes to compare the use of sodium hypochlorite and chlorhexidine during root canal therapy are needed. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Statistical auditing and randomness test of lotto k/N-type games

NASA Astrophysics Data System (ADS)

Coronel-Brizio, H. F.; Hernández-Montoya, A. R.; Rapallo, F.; Scalas, E.

2008-11-01

One of the most popular lottery games worldwide is the so-called “lotto k/N”. It considers N numbers 1,2,…,N from which k are drawn randomly, without replacement. A player selects k or more numbers and the first prize is shared amongst those players whose selected numbers match all of the k randomly drawn. Exact rules may vary in different countries. In this paper, mean values and covariances for the random variables representing the numbers drawn from this kind of game are presented, with the aim of using them to audit statistically the consistency of a given sample of historical results with theoretical values coming from a hypergeometric statistical model. The method can be adapted to test pseudorandom number generators.

North York Fall Norms for Boys and Girls Age 12-14 for: CAHPER Tests; Measures of Aerobic Fitness; Peak Flow; Muscle Strength; Percent Body Fat.

ERIC Educational Resources Information Center

Thompson, Patricia

Tests are described that were given to 1,000 students randomly selected at grade 7-9 levels with an equal representation from both sexes. Participants were selected from two junior high schools in North York for a study comparing students in a regular physical education program to those in a program to develop cardiovascular endurance. The first…

Evaluation of the "Energize Your Life!" Social Marketing Campaign Pilot Study to Increase Fruit Intake among Community College Students

ERIC Educational Resources Information Center

Shive, Steven E.; Morris, Michelle Neyman

2006-01-01

In this study, the authors evaluated the effectiveness of the "Energize Your Life!" social-marketing campaign pilot study to improve knowledge, attitudes, and fruit intake among community college students. The authors used a cross-sectional, quasi-experimental, pre- and posttest design. They randomly selected community college students…

A Study of Reliability of Marking and Absolute Grading in Secondary Schools

ERIC Educational Resources Information Center

Abdul Gafoor, K.; Jisha, P.

2014-01-01

Using a non-experimental comparative group design in a sample consisting of 100 English teachers randomly selected from 30 secondary schools of a district of Kerala and assigning fifty teachers to groups for marking and grading, this study compares inter and intra-individual reliability in marking and absolute grading. Studying (1) the in marking…

A Comparative Study of Factors Influencing Male and Female Lecturers' Job Satisfaction in Ghanaian Higher Education

ERIC Educational Resources Information Center

Amos, Patricia Mawusi; Acquah, Sakina; Antwi, Theresa; Adzifome, Nixon Saba

2015-01-01

The study sought to compare factors influencing male and female lecturers' job satisfaction. Cross-sectional survey designs employing both quantitative and qualitative approaches were adopted for the study. Simple random sampling was used to select 163 lecturers from the four oldest public universities in Ghana. Celep's (2000) Organisational…

The Perception of Public Secondary Education through the Lens of African American Male Students

ERIC Educational Resources Information Center

Dandridge, Janae' K.

2012-01-01

This study examines the perspective of public secondary education through the lived experiences and voices of 10 African American male students. The study was qualitative in nature and utilized an action research case study design. The researcher conducted semi structured interviews with a randomly selected group of African American male students…

Teachers' Perceptions of Predicted Career Success of Students Who Choose Nontraditional Occupational Careers.

ERIC Educational Resources Information Center

Epler, Doris M.

A study analyzed the way teachers perceive potential employment success for nontraditional students. The study population consisted of a stratified random selection of 120 non-vocational and 64 vocational teachers from schools in Berks County, Pennsylvania. To measure the teachers' sex bias and dogmatism, the researcher used a case study approach.…

The Relationship between Monogamous/Polygamous Family Structure and the Mental Health of Bedouin Arab Adolescents

ERIC Educational Resources Information Center

Elbedour, S.; Bart, William; Hektner, Joel

2007-01-01

Previous studies of polygamy and child mental health have primarily focused on younger children. The present studies are among the first to focus on adolescents. The first study involved 210 randomly selected Bedouin Arab adolescents (mean age 15.9), who were administered instruments assessing their family environment and mental health. The second…

Relationship between Psychological Well-Being and Smartphone Addiction of University Students

ERIC Educational Resources Information Center

Kumcagiz, Hatice; Gündüz, Yüksel

2016-01-01

This study was carried out to examine the relationship between university students' levels of psychological well-being and smartphone addiction. The study group consists of a total of 408 students (303 female and 105 male) selected by random sampling method and studying at the departments of Primary Education, Science Teaching, Art and Crafts…

Research Issues in the Study of Public Attitudes toward Ethical Problems in Television Programming.

ERIC Educational Resources Information Center

Rarick, David L.; Lind, Rebecca Ann

Three empirical studies focused on viewer reactions to ethical issues in television news, and on actions audience members felt were appropriate to control possibly unethical behaviors in television broadcasting. The first study was a 12-minute telephone survey of 293 randomly selected adults in Minneapolis-St. Paul (Minnesota) in 1989 to determine…

Visual Literacy and the Integration of Parametric Modeling in the Problem-Based Curriculum

ERIC Educational Resources Information Center

Assenmacher, Matthew Benedict

2013-01-01

This quasi-experimental study investigated the application of visual literacy skills in the form of parametric modeling software in relation to traditional forms of sketching. The study included two groups of high school technical design students. The control and experimental groups involved in the study consisted of two randomly selected groups…

Factors Affecting the Unemployment (Rate) of Female Art Graduates in Iran

ERIC Educational Resources Information Center

Hedayat, Mina; Kahn, Sabzali Musa; Hanafi, Jaffri

2013-01-01

The aim of this study is to explore the relationship between the opportunities of female artist graduates in Tehran Province and the current employment market. Mixed method was employed in this study. The population of the current study consisted of 240 female artist graduates selected using a systematic random sampling method from both public and…

Service Quality of State Universities in Turkey: The Case of Ankara

ERIC Educational Resources Information Center

Eres, Figen

2011-01-01

The aim of this study is determine the service quality perceptions of students being educated at state universities in Ankara. The sample of the study is composed of final grade students of faculties of Economics and Administrative Sciences. The sample of the study is composed of a total of randomly selected students. There were 416 returned…

English as Second Language: Students' Awareness of Learning Strategies Used in Reading Comprehension

ERIC Educational Resources Information Center

Hussain, Irshad; Javed, Muhammad; Munshi, Parveen

2015-01-01

This study investigated the reading strategies used by adult learners' to read materials in English language for their studies. The population of the study consisted of students of Universiti Sains Malaysia. A sample of 80 (40 Postgraduates and 40 Undergraduates) TESOL students enrolled in the University were selected randomly. The data were…

Analysis of Ego Identity Status of School of Physical Education and Sports

ERIC Educational Resources Information Center

Turan, Mehmet Behzat; Koç, Kenan; Karaoglu, Baris

2017-01-01

This study aimed to analyze ego identity status of the candidates who studied in school of physical education and sports. For this purpose, randomly selected 651 individuals, who attended to Kayseri Erciyes University, school of physical education and sports, were included to this study. In this research, Extended Objective Measure of Ego Identity…

The Degree of Symmetrical among the Teaching Staff at Tafila Technical University

ERIC Educational Resources Information Center

Kraimeen, Hani; Al-Hajaya, Suleiman

2017-01-01

The study was conducted to identify the degree of symmetrical among the teaching staff members at Tafila Technical University. The study community was comprised of all the 239 members of the teaching staff at Tafila Technical University. The study sample was selected by using the stratified random method according to the faculty variable which…

Obstacles of Teaching Mathematics Faced by the Class Teachers in Jordan

ERIC Educational Resources Information Center

Nejem, Khamis Mousa; Muhanna, Waffa

2013-01-01

The purpose of the study is to investigate the obstacles of teaching mathematics faced by the class teachers in Jordan. To achieve this purpose a study sample of 192 male and female class teachers was selected randomly from government schools. The instrument of the study was a questionnaire used to investigate the obstacles of mathematics…

Performing an Event Study: An Exercise for Finance Students

ERIC Educational Resources Information Center

Reese, William A., Jr.; Robins, Russell P.

2017-01-01

This exercise helps instructors teach students how to perform a simple event study. The study tests to see if stocks earn abnormal returns when added to the S&P 500. Students select a random sample of stocks that were added to the index between January 2000 and July 2015. The accompanying spreadsheet calculates cumulative abnormal returns and…

Teachers' Difficulties in Preparation and Implementation of Performance Task

ERIC Educational Resources Information Center

Metin, Mustafa

2013-01-01

The aim of study is to determinate the difficulties of teachers in preparation and implementation of performance task. This study was carried out with 25 teachers (5 science and technology, 5 primary, 5 mathematic, 5 social science and 5 Turkish teachers) who working at elementary schools in Artvin. Sample of study is selected randomly. Case study…

Group Random Call Can Positively Affect Student In-Class Clicker Discussions

PubMed Central

Knight, Jennifer K.; Wise, Sarah B.; Sieke, Scott

2016-01-01

Understanding how instructional techniques and classroom norms influence in-class student interactions has the potential to positively impact student learning. Many previous studies have shown that students benefit from discussing their ideas with one another in class. In this study of introductory biology students, we explored how using an in-class accountability system might affect the nature of clicker-question discussions. Clicker-question discussions in which student groups were asked to report their ideas voluntarily (volunteer call) were compared with discussions in which student groups were randomly selected to report their ideas (random call). We hypothesized that the higher-accountability condition (random call) would impress upon students the importance of their discussions and thus positively influence how they interacted. Our results suggest that a higher proportion of discussions in the random call condition contained exchanges of reasoning, some forms of questioning, and both on- and off-topic comments compared with discussion in the volunteer call condition. Although group random call does not impact student performance on clicker questions, the positive impact of this instructional approach on exchanges of reasoning and other features suggests it may encourage some types of student interactions that support learning. PMID:27856544

Study of Randomness in AES Ciphertexts Produced by Randomly Generated S-Boxes and S-Boxes with Various Modulus and Additive Constant Polynomials

NASA Astrophysics Data System (ADS)

Das, Suman; Sadique Uz Zaman, J. K. M.; Ghosh, Ranjan

2016-06-01

In Advanced Encryption Standard (AES), the standard S-Box is conventionally generated by using a particular irreducible polynomial {11B} in GF(28) as the modulus and a particular additive constant polynomial {63} in GF(2), though it can be generated by many other polynomials. In this paper, it has been shown that it is possible to generate secured AES S-Boxes by using some other selected modulus and additive polynomials and also can be generated randomly, using a PRNG like BBS. A comparative study has been made on the randomness of corresponding AES ciphertexts generated, using these S-Boxes, by the NIST Test Suite coded for this paper. It has been found that besides using the standard one, other moduli and additive constants are also able to generate equally or better random ciphertexts; the same is true for random S-Boxes also. As these new types of S-Boxes are user-defined, hence unknown, they are able to prevent linear and differential cryptanalysis. Moreover, they act as additional key-inputs to AES, thus increasing the key-space.

The effects of probiotic and synbiotic supplementation on metabolic syndrome indices in adults at risk of type 2 diabetes: study protocol for a randomized controlled trial.

PubMed

Kassaian, Nazila; Aminorroaya, Ashraf; Feizi, Awat; Jafari, Parvaneh; Amini, Masoud

2017-03-29

The incidence of type 2 diabetes, cardiovascular diseases, and obesity has been rising dramatically; however, their pathogenesis is particularly intriguing. Recently, dysbiosis of the intestinal microbiota has emerged as a new candidate that may be linked to metabolic diseases. We hypothesize that selective modulation of the intestinal microbiota by probiotic or synbiotic supplementation may improve metabolic dysfunction and prevent diabetes in prediabetics. In this study, a synthesis and study of synbiotics will be carried out for the first time in Iran. In a randomized triple-blind controlled clinical trial, 120 adults with impaired glucose tolerance based on the inclusion criteria will be selected by a simple random sampling method and will be randomly allocated to 6 months of 6 g/d probiotic, synbiotic or placebo. The fecal abundance of bacteria, blood pressure, height, weight, and waist and hip circumferences will be measured at baseline and following treatment. Also, plasma lipid profiles, HbA1C, fasting plasma glucose, and insulin levels, will be measured and insulin resistance (HOMA-IR) and beta-cell function (HOMA-B) will be calculated at baseline and will be repeated at months 3, 6, 12, and 18. The data will be compared within and between groups using statistical methods. The results of this trial could contribute to the evidence-based clinical guidelines that address gut microbiota manipulation to maximize health benefits in prevention and management of metabolic syndrome in prediabetes. Iranian Registry of Clinical Trials: IRCT201511032321N2 . Registered on 27 February 2016.

Potential of Using Mobile Phone Data to Assist in Mission Analysis and Area of Operations Planning

DTIC Science & Technology

2015-08-01

tremendously beneficial especially since a sizeable portion of the population are nomads , changing location based on season. A proper AO...provided: a. User_id: Selected User’s random ID b. Timestamp: 24 h format YYYY-MM-DD-HH:M0:00 (the second digits of the minutes and all the seconds...yearly were selected. This data provided: a. User_id: Selected User’s random ID b. Timestamp: 24 h format YYYY-MM-DD-HH:M0:00 (the second digits

Discriminative Projection Selection Based Face Image Hashing

NASA Astrophysics Data System (ADS)

Karabat, Cagatay; Erdogan, Hakan

Face image hashing is an emerging method used in biometric verification systems. In this paper, we propose a novel face image hashing method based on a new technique called discriminative projection selection. We apply the Fisher criterion for selecting the rows of a random projection matrix in a user-dependent fashion. Moreover, another contribution of this paper is to employ a bimodal Gaussian mixture model at the quantization step. Our simulation results on three different databases demonstrate that the proposed method has superior performance in comparison to previously proposed random projection based methods.

Topology-selective jamming of fully-connected, code-division random-access networks

NASA Technical Reports Server (NTRS)

Polydoros, Andreas; Cheng, Unjeng

1990-01-01

The purpose is to introduce certain models of topology selective stochastic jamming and examine its impact on a class of fully-connected, spread-spectrum, slotted ALOHA-type random access networks. The theory covers dedicated as well as half-duplex units. The dominant role of the spatial duty factor is established, and connections with the dual concept of time selective jamming are discussed. The optimal choices of coding rate and link access parameters (from the users' side) and the jamming spatial fraction are numerically established for DS and FH spreading.

Antitumor Efficacy Testing in Rodents

PubMed Central

2008-01-01

The preclinical research and human clinical trials necessary for developing anticancer therapeutics are costly. One contributor to these costs is preclinical rodent efficacy studies, which, in addition to the costs associated with conducting them, often guide the selection of agents for clinical development. If inappropriate or inaccurate recommendations are made on the basis of these preclinical studies, then additional costs are incurred. In this commentary, I discuss the issues associated with preclinical rodent efficacy studies. These include the identification of proper preclinical efficacy models, the selection of appropriate experimental endpoints, and the correct statistical evaluation of the resulting data. I also describe important experimental design considerations, such as selecting the drug vehicle, optimizing the therapeutic treatment plan, properly powering the experiment by defining appropriate numbers of replicates in each treatment arm, and proper randomization. Improved preclinical selection criteria can aid in reducing unnecessary human studies, thus reducing the overall costs of anticancer drug development. PMID:18957675

Should Controls With Respiratory Symptoms Be Excluded From Case-Control Studies of Pneumonia Etiology? Reflections From the PERCH Study.

PubMed

Higdon, Melissa M; Hammitt, Laura L; Deloria Knoll, Maria; Baggett, Henry C; Brooks, W Abdullah; Howie, Stephen R C; Kotloff, Karen L; Levine, Orin S; Madhi, Shabir A; Murdoch, David R; Scott, J Anthony G; Thea, Donald M; Driscoll, Amanda J; Karron, Ruth A; Park, Daniel E; Prosperi, Christine; Zeger, Scott L; O'Brien, Katherine L; Feikin, Daniel R

2017-06-15

Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrollment or analyses. Herein we argue that selecting controls regardless of respiratory symptoms provides the least biased estimates of pneumonia etiology. We review 3 reasons investigators may choose to exclude controls with respiratory symptoms in light of epidemiologic principles of control selection and present data from the Pneumonia Etiology Research for Child Health (PERCH) study where relevant to assess their validity. We conclude that exclusion of controls with respiratory symptoms will result in biased estimates of etiology. Randomly selected community controls, with or without respiratory symptoms, as long as they do not meet the criteria for case-defining pneumonia, are most representative of the general population from which cases arose and the least subject to selection bias. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

Feasibility of collecting 24-h urine to monitor sodium intake in the National Health and Nutrition Examination Survey123

PubMed Central

Terry, Ana L; Cogswell, Mary E; Wang, Chia-Yih; Chen, Te-Ching; Loria, Catherine M; Wright, Jacqueline D; Zhang, Xinli; Lacher, David A; Merritt, Robert K; Bowman, Barbara A

2016-01-01

Background: Twenty-four–hour urine sodium excretion is recommended for monitoring population sodium intake. Because of concerns about participation and completion, sodium excretion has not been collected previously in US nationally representative surveys. Objective: We assessed the feasibility of implementing 24-h urine collections as part of a nationally representative survey. Design: We selected a random half sample of nonpregnant US adults aged 20–69 y in 3 geographic locations of the 2013 NHANES. Participants received explicit instructions, started and ended the urine collection in a urine study mobile examination center, and answered questions about their collection. Among those with a complete 24-h urine collection, a random one-half were asked to collect a second 24-h urine sample. Sodium, potassium, chloride, and creatinine excretion were analyzed. Results: The final NHANES examination response rate for adults aged 20–69 y in these 3 study locations was 71%. Of those examined (n = 476), 282 (59%) were randomly selected to participate in the 24-h urine collection. Of these, 212 persons [75% of those selected for 24-h urine collection; 53% (equal to 71% × 75% of those selected for the NHANES)] collected a complete initial 24-h specimen and 92 persons (85% of 108 selected) collected a second complete 24-h urine sample. More men than women completed an initial collection (P = 0.04); otherwise, completion did not vary by sociodemographic characteristics, body mass index, education, or employment status for either collection. Mean 24-h urine volume and sodium excretion were 1964 ± 1228 mL and 3657 ± 2003 mg, respectively, for the first 24-h urine sample, and 2048 ± 1288 mL and 3773 ± 1891 mg, respectively, for the second collection. Conclusion: Given the 53% final component response rate and 75% completion rate, 24-h urine collections were deemed feasible and implemented in the NHANES 2014 on a subsample of adults aged 20–69 y to assess population sodium intake. This study was registered at clinicaltrials.gov as NCT02723682. PMID:27413136

Development of Solution Algorithm and Sensitivity Analysis for Random Fuzzy Portfolio Selection Model

NASA Astrophysics Data System (ADS)

Hasuike, Takashi; Katagiri, Hideki

2010-10-01

This paper focuses on the proposition of a portfolio selection problem considering an investor's subjectivity and the sensitivity analysis for the change of subjectivity. Since this proposed problem is formulated as a random fuzzy programming problem due to both randomness and subjectivity presented by fuzzy numbers, it is not well-defined. Therefore, introducing Sharpe ratio which is one of important performance measures of portfolio models, the main problem is transformed into the standard fuzzy programming problem. Furthermore, using the sensitivity analysis for fuzziness, the analytical optimal portfolio with the sensitivity factor is obtained.

Selection of examples in case-based computer-aided decision systems

PubMed Central

Mazurowski, Maciej A.; Zurada, Jacek M.; Tourassi, Georgia D.

2013-01-01

Case-based computer-aided decision (CB-CAD) systems rely on a database of previously stored, known examples when classifying new, incoming queries. Such systems can be particularly useful since they do not need retraining every time a new example is deposited in the case base. The adaptive nature of case-based systems is well suited to the current trend of continuously expanding digital databases in the medical domain. To maintain efficiency, however, such systems need sophisticated strategies to effectively manage the available evidence database. In this paper, we discuss the general problem of building an evidence database by selecting the most useful examples to store while satisfying existing storage requirements. We evaluate three intelligent techniques for this purpose: genetic algorithm-based selection, greedy selection and random mutation hill climbing. These techniques are compared to a random selection strategy used as the baseline. The study is performed with a previously presented CB-CAD system applied for false positive reduction in screening mammograms. The experimental evaluation shows that when the development goal is to maximize the system’s diagnostic performance, the intelligent techniques are able to reduce the size of the evidence database to 37% of the original database by eliminating superfluous and/or detrimental examples while at the same time significantly improving the CAD system’s performance. Furthermore, if the case-base size is a main concern, the total number of examples stored in the system can be reduced to only 2–4% of the original database without a decrease in the diagnostic performance. Comparison of the techniques shows that random mutation hill climbing provides the best balance between the diagnostic performance and computational efficiency when building the evidence database of the CB-CAD system. PMID:18854606

Combined cognitive-strategy and task-specific training improves transfer to untrained activities in sub-acute stroke: An exploratory randomized controlled trial

PubMed Central

McEwen, Sara; Polatajko, Helene; Baum, Carolyn; Rios, Jorge; Cirone, Dianne; Doherty, Meghan; Wolf, Timothy

2014-01-01

Purpose The purpose of this study was to estimate the effect of the Cognitive Orientation to daily Occupational Performance (CO-OP) approach compared to usual outpatient rehabilitation on activity and participation in people less than 3 months post stroke. Methods An exploratory, single blind, randomized controlled trial with a usual care control arm was conducted. Participants referred to 2 stroke rehabilitation outpatient programs were randomized to receive either Usual Care or CO-OP. The primary outcome was actual performance of trained and untrained self-selected activities, measured using the Performance Quality Rating Scale (PQRS). Additional outcomes included the Canadian Occupational Performance Measure (COPM), the Stroke Impact Scale Participation Domain, the Community Participation Index, and the Self Efficacy Gauge. Results Thirty-five (35) eligible participants were randomized; 26 completed the intervention. Post-intervention, PQRS change scores demonstrated CO-OP had a medium effect over Usual Care on trained self-selected activities (d=0.5) and a large effect on untrained (d=1.2). At a 3 month follow-up, PQRS change scores indicated a large effect of CO-OP on both trained (d=1.6) and untrained activities (d=1.1). CO-OP had a small effect on COPM and a medium effect on the Community Participation Index perceived control and the Self-Efficacy Gauge. Conclusion CO-OP was associated with a large treatment effect on follow up performances of self-selected activities, and demonstrated transfer to untrained activities. A larger trial is warranted. PMID:25416738

Combined Cognitive-Strategy and Task-Specific Training Improve Transfer to Untrained Activities in Subacute Stroke: An Exploratory Randomized Controlled Trial.

PubMed

McEwen, Sara; Polatajko, Helene; Baum, Carolyn; Rios, Jorge; Cirone, Dianne; Doherty, Meghan; Wolf, Timothy

2015-07-01

The purpose of this study was to estimate the effect of the Cognitive Orientation to daily Occupational Performance (CO-OP) approach compared with usual outpatient rehabilitation on activity and participation in people <3 months poststroke. An exploratory, single-blind, randomized controlled trial, with a usual-care control arm, was conducted. Participants referred to 2 stroke rehabilitation outpatient programs were randomized to receive either usual care or CO-OP. The primary outcome was actual performance of trained and untrained self-selected activities, measured using the Performance Quality Rating Scale (PQRS). Additional outcomes included the Canadian Occupational Performance Measure (COPM), the Stroke Impact Scale Participation Domain, the Community Participation Index, and the Self-Efficacy Gauge. A total of 35 eligible participants were randomized; 26 completed the intervention. Post intervention, PQRS change scores demonstrated that CO-OP had a medium effect over usual care on trained self-selected activities (d = 0.5) and a large effect on untrained activities (d = 1.2). At a 3-month follow-up, PQRS change scores indicated a large effect of CO-OP on both trained (d = 1.6) and untrained activities (d = 1.1). CO-OP had a small effect on COPM and a medium effect on the Community Participation Index perceived control and on the Self-Efficacy Gauge. CO-OP was associated with a large treatment effect on follow-up performances of self-selected activities and demonstrated transfer to untrained activities. A larger trial is warranted. © The Author(s) 2014.

Selecting Random Distributed Elements for HIFU using Genetic Algorithm

NASA Astrophysics Data System (ADS)

Zhou, Yufeng

2011-09-01

As an effective and noninvasive therapeutic modality for tumor treatment, high-intensity focused ultrasound (HIFU) has attracted attention from both physicians and patients. New generations of HIFU systems with the ability to electrically steer the HIFU focus using phased array transducers have been under development. The presence of side and grating lobes may cause undesired thermal accumulation at the interface of the coupling medium (i.e. water) and skin, or in the intervening tissue. Although sparse randomly distributed piston elements could reduce the amplitude of grating lobes, there are theoretically no grating lobes with the use of concave elements in the new phased array HIFU. A new HIFU transmission strategy is proposed in this study, firing a number of but not all elements for a certain period and then changing to another group for the next firing sequence. The advantages are: 1) the asymmetric position of active elements may reduce the side lobes, and 2) each element has some resting time during the entire HIFU ablation (up to several hours for some clinical applications) so that the decreasing efficiency of the transducer due to thermal accumulation is minimized. Genetic algorithm was used for selecting randomly distributed elements in a HIFU array. Amplitudes of the first side lobes at the focal plane were used as the fitness value in the optimization. Overall, it is suggested that the proposed new strategy could reduce the side lobe and the consequent side-effects, and the genetic algorithm is effective in selecting those randomly distributed elements in a HIFU array.

Colorectal Adenomas in Participants of the SELECT Randomized Trial of Selenium and Vitamin E for Prostate Cancer Prevention

PubMed Central

Lance, Peter; Alberts, David S.; Thompson, Patricia A.; Fales, Liane; Wang, Fang; Jose, Jerilyn San; Jacobs, Elizabeth T.; Goodman, Phyllis J.; Darke, Amy K.; Yee, Monica; Minasian, Lori; Thompson, Ian M.; Roe, Denise J.

2017-01-01

Selenium and vitamin E micronutrients have been advocated for the prevention of colorectal cancer. Colorectal adenoma occurrence was used as a surrogate for colorectal cancer in an ancillary study to the Selenium and Vitamin E Cancer Prevention Trial (SELECT) for prostate cancer prevention. The primary objective was to measure the effect of selenium (as selenomethionine) on colorectal adenomas occurrence, with the effect of vitamin E (as alpha tocopherol) supplementation on colorectal adenoma occurrence considered as a secondary objective. Participants who underwent lower endoscopy while in SELECT were identified from a subgroup of the 35,533 men randomized in the trial. Adenoma occurrence was ascertained from the endoscopy and pathology reports for these procedures. Relative risk (RR) estimates and 95% confidence intervals (CI) of adenoma occurrence were generated comparing those randomized to selenium versus placebo and to vitamin E versus placebo based on the full factorial design. Evaluable endoscopy information was obtained for 6,546 participants, of whom 2,286 had 1+ adenomas. Apart from 21 flexible sigmoidoscopies, all the procedures yielding adenomas were colonoscopies. Adenomas occurred in 34.2% and 35.7%, respectively, of participants whose intervention included or did not include selenium. Compared with placebo, the RR for adenoma occurrence in participants randomized to selenium was 0.96 (95% CI, 0.90–1.02; P = 0.194). Vitamin E did not affect adenoma occurrence compared to placebo (RR = 1.03, 95% CI, 0.96–1.10; P = 0.38). Neither selenium nor vitamin E supplementation can be recommended for colorectal adenoma prevention. PMID:27777235

Observational Research Rigor Alone Does Not Justify Causal Inference

PubMed Central

Ejima, Keisuke; Li, Peng; Smith, Daniel L.; Nagy, Tim R.; Kadish, Inga; van Groen, Thomas; Dawson, John A.; Yang, Yongbin; Patki, Amit; Allison, David B.

2016-01-01

Background Differing opinions exist on whether associations obtained in observational studies can be reliable indicators of a causal effect if the observational study is sufficiently well controlled and executed. Materials and methods To test this, we conducted two animal observational studies that were rigorously controlled and executed beyond what is achieved in studies of humans. In study 1, we randomized 332 genetically identical C57BL/6J mice into three diet groups with differing food energy allotments and recorded individual self-selected daily energy intake and lifespan. In study 2, 60 male mice (CD1) were paired and divided into two groups for a 2-week feeding regimen. We evaluated the association between weight gain and food consumption. Within each pair, one animal was randomly assigned to an S group in which the animals had free access to food. The second paired animal (R group) was provided exactly the same diet that their S partner ate the day before. Results In study 1, across all three groups, we found a significant negative effect of energy intake on lifespan. However, we found a positive association between food intake and lifespan among the ad libitum feeding group: 29.99 (95% CI: 8.2 to 51.7) days per daily kcal. In study 2, we found a significant (P=0.003) group (randomized vs self-selected)-by-food consumption interaction effect on weight gain. Conclusions At least in nutrition research, associations derived from observational studies may not be reliable indicators of causal effects, even with the most rigorous study designs achievable. PMID:27711975

Evaluation of variable selection methods for random forests and omics data sets.

PubMed

Degenhardt, Frauke; Seifert, Stephan; Szymczak, Silke

2017-10-16

Machine learning methods and in particular random forests are promising approaches for prediction based on high dimensional omics data sets. They provide variable importance measures to rank predictors according to their predictive power. If building a prediction model is the main goal of a study, often a minimal set of variables with good prediction performance is selected. However, if the objective is the identification of involved variables to find active networks and pathways, approaches that aim to select all relevant variables should be preferred. We evaluated several variable selection procedures based on simulated data as well as publicly available experimental methylation and gene expression data. Our comparison included the Boruta algorithm, the Vita method, recurrent relative variable importance, a permutation approach and its parametric variant (Altmann) as well as recursive feature elimination (RFE). In our simulation studies, Boruta was the most powerful approach, followed closely by the Vita method. Both approaches demonstrated similar stability in variable selection, while Vita was the most robust approach under a pure null model without any predictor variables related to the outcome. In the analysis of the different experimental data sets, Vita demonstrated slightly better stability in variable selection and was less computationally intensive than Boruta.In conclusion, we recommend the Boruta and Vita approaches for the analysis of high-dimensional data sets. Vita is considerably faster than Boruta and thus more suitable for large data sets, but only Boruta can also be applied in low-dimensional settings. © The Author 2017. Published by Oxford University Press.

Modified Bat Algorithm for Feature Selection with the Wisconsin Diagnosis Breast Cancer (WDBC) Dataset

PubMed

Jeyasingh, Suganthi; Veluchamy, Malathi

2017-05-01

Early diagnosis of breast cancer is essential to save lives of patients. Usually, medical datasets include a large variety of data that can lead to confusion during diagnosis. The Knowledge Discovery on Database (KDD) process helps to improve efficiency. It requires elimination of inappropriate and repeated data from the dataset before final diagnosis. This can be done using any of the feature selection algorithms available in data mining. Feature selection is considered as a vital step to increase the classification accuracy. This paper proposes a Modified Bat Algorithm (MBA) for feature selection to eliminate irrelevant features from an original dataset. The Bat algorithm was modified using simple random sampling to select the random instances from the dataset. Ranking was with the global best features to recognize the predominant features available in the dataset. The selected features are used to train a Random Forest (RF) classification algorithm. The MBA feature selection algorithm enhanced the classification accuracy of RF in identifying the occurrence of breast cancer. The Wisconsin Diagnosis Breast Cancer Dataset (WDBC) was used for estimating the performance analysis of the proposed MBA feature selection algorithm. The proposed algorithm achieved better performance in terms of Kappa statistic, Mathew’s Correlation Coefficient, Precision, F-measure, Recall, Mean Absolute Error (MAE), Root Mean Square Error (RMSE), Relative Absolute Error (RAE) and Root Relative Squared Error (RRSE). Creative Commons Attribution License

Randomized controlled trial of probiotics for the prevention of spontaneous preterm delivery associated with intrauterine infection: study protocol

PubMed Central

2010-01-01

Background Spontaneous preterm deliveries that occur before the 34th week of gestation, and particularly before the 32nd week of gestation, have been strongly associated to intrauterine infection, ascending from vagina, and represent the largest portion of neonatal deaths and neurological problems. Bacterial vaginosis, characterized by a diminished or absent flora of lactobacilli and increased colonization of several anaerobic or facultative microorganisms, increases two times the risk of preterm delivery before the 34th week. Trials of antibiotics failed to show efficacy and effectiveness against spontaneous preterm birth related to bacterial vaginosis. Some studies indicate benefit from selected probiotics to treat genitourinary infections, including bacterial vaginosis. Objective The purpose of this study is to evaluate the effectiveness of the early administration of selected probiotics to pregnant women with asymptomatic bacterial vaginosis/intermediate degree infection to reduce the occurrence of spontaneous preterm delivery and related neonatal mortality and morbidity. Methods/Design Women attending public prenatal care services in Rio de Janeiro will be screened to select asymptomatic pregnant women, less than 20 weeks' gestation, with no indication of elective preterm delivery. Those with vaginal pH > = 4.5 and a Nugent score between 4 and 10 (intermediate degree infection or bacterial vaginosis) will be randomized to either the placebo or the intervention group, after written informed consent. Intervention consists in the use of probiotics, Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14, 2 capsules a day, each capsule containing more than one million bacilli of each strain, for 6-12 weeks, up to the 24th-25th wk of gestation. Ancillary analyses include quantification of selected cervicovaginal cytokines and genotyping of selected polymorphisms. The randomization process is stratified for history of preterm delivery and blocked. Allocation concealment was designed as well as blinding of women, caregivers and outcome evaluators. The study will be supervised by an independent monitoring committee. Outcomes under study are preterm delivery (< 34- < 32 weeks of gestation) and associated neonatal complications: early neonatal sepsis, bronchopulmonary dysplasia, periventricular leukomalacia, necrotizing enterocolitis, and prematurity-related retinopathy; definitions were adapted from those recommended by the 2002 version of the Vermont-Oxford Network. Trial registration at NIH register: NCT00303082. PMID:20591191

Analytical Study of E-Learning Resources in National Open University of Nigeria

ERIC Educational Resources Information Center

Ajegbomogun, Fredrick Olatunji; Okunlaya, Rifqah Olufunmilayo Afolake; Alawiye, Mariam Kehinde

2017-01-01

This paper analyses e-learning resources in the National Open University of Nigeria (NOUN) using Abeokuta study center. Survey research method was adopted for this study. A questionnaire was designed and used to collect data for this study. A sample of 150 respondents was randomly selected from the final year students in the six schools of the…

A Study of the Cognitive and Affective Performance of Children in the Elementary Science Study Program.

ERIC Educational Resources Information Center

Henson, Stanley

Three studies are reported for children participating in the Elementary Science Study (ESS) program. They are the cognitive and affective performances and the classroom learning environment. Three groups of ESS children were evaluated: nine-year-olds, ten-year-olds, and eleven-year-olds. Each age group contained 30 randomly selected subjects. The…

Internet and Internet Use: Teacher Trainees' Perspective

ERIC Educational Resources Information Center

Akinoglu, Orhan

2009-01-01

The aim of this study is to present the development and issues of internet and internet use. The study has a descriptive survey design and 185 randomly selected teacher trainees at Marmara University, Ataturk Education Faculty in the 2001-2002 academic year constitute the sample. Data were collected via a questionnaire prepared by the researcher…

The Relationships between Language Learning Strategies and Positive Emotions among Malaysian ESL Undergraduates

ERIC Educational Resources Information Center

Mohammadipour, Mohammad; Rashid, Sabariah Md; Rafik-Galea, Shameem; Thai, Yap Ngee

2018-01-01

Emotions are an indispensable part of second language learning. The aim of this study is to determine the relationship between the use of language learning strategies and positive emotions. The present study adopted a sequential mixed methods design. The participants were 300 Malaysian ESL undergraduates selected through stratified random sampling…

2005 Workforce Study: Ohio Early Childhood Centers. General Analysis

ERIC Educational Resources Information Center

Stoneburner, Chris

2006-01-01

The purpose of this study was to understand the characteristics of the current workforce in early childhood. This report highlights key characteristics of the 2005 early childhood center workforce in Ohio. Survey packets were sent to 3.600 randomly selected centers in April 2005, representing centers licensed by the Ohio Department of Job and…

Logging utilization in Idaho: Current and past trends

Treesearch

Eric A. Simmons; Todd A. Morgan; Erik C. Berg; Stanley J. Zarnoch; Steven W. Hayes; Mike T. Thompson

2014-01-01

A study of commercial timber-harvesting activities in Idaho was conducted during 2008 and 2011 to characterize current tree utilization, logging operations, and changes from previous Idaho logging utilization studies. A two-stage simple random sampling design was used to select sites and felled trees for measurement within active logging sites. Thirty-three logging...

Some Factors Effected Student's Calculus Learning Outcome

ERIC Educational Resources Information Center

Rajagukguk, Wamington

2016-01-01

The purpose of this study is to determine the factors effected calculus learning outcome of the student. This study was conducted with 176 respondents, which were selected randomly. The data were obtained by questionnaire, and then analyzed by using multiple regressions, and correlation, at level of a = 0.05. The findings showed there is the…