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1

Childhood temperament: passive gene-environment correlation, gene-environment interaction, and the hidden importance of the family environment.  

PubMed

Biological parents pass on genotypes to their children, as well as provide home environments that correlate with their genotypes; thus, the association between the home environment and children's temperament can be genetically (i.e., passive gene-environment correlation) or environmentally mediated. Furthermore, family environments may suppress or facilitate the heritability of children's temperament (i.e., gene-environment interaction). The sample comprised 807 twin pairs (mean age = 7.93 years) from the longitudinal Wisconsin Twin Project. Important passive gene-environment correlations emerged, such that home environments were less chaotic for children with high effortful control, and this association was genetically mediated. Children with high extraversion/surgency experienced more chaotic home environments, and this correlation was also genetically mediated. In addition, heritability of children's temperament was moderated by home environments, such that effortful control and extraversion/surgency were more heritable in chaotic homes, and negative affectivity was more heritable under crowded or unsafe home conditions. Modeling multiple types of gene-environment interplay uncovered the complex role of genetic factors and the hidden importance of the family environment for children's temperament and development more generally. PMID:23398752

Lemery-Chalfant, Kathryn; Kao, Karen; Swann, Gregory; Goldsmith, H Hill

2013-02-01

2

Examining the role of passive gene-environment correlation in childhood depression using a novel genetically sensitive design.  

PubMed

Parental depression is associated with disruptions in the parent-child relationship, exposure to stressful family life events, and offspring depressive symptoms. Evidence suggests that intergenerational transmission of depression involves environmental and inherited contributions. We sought to evaluate the role of passive gene-environment correlation (rGE) in relation to depression, family life events that were due to parental behavior, and parental positivity in a sample where children varied in genetic relatedness to their rearing parents. Our study included 865 families with children born through assisted conception (444 related to both parents, 210 related to the mother only, 175 related to the father only, and 36 related to neither parent). Consistent with previous studies, the intergenerational transmission of depressive symptoms was largely due to environmental factors, although parent and child gender influenced results. Maternal and paternal depressive symptoms were associated with reduced positivity and increased parentally imposed life events regardless of parent-child relatedness. Results of path analysis were consistent with passive rGE for both maternal and paternal positivity in that positivity partially mediated the link between maternal/paternal depression and child depression only in genetically related parent-child pairs. Results also suggested passive rGE involving parentally imposed life events for mothers and fathers although passive rGE effects were smaller than for positivity. PMID:23398751

Rice, Frances; Lewis, Gemma; Harold, Gordon T; Thapar, Anita

2013-02-01

3

Gene-environment correlations in the stress-depression relationship.  

PubMed

A critical feature of the social stress model is the apparent relationship between stress and depression. Although many studies have demonstrated a connection between the two, the relationship may be contaminated by genes affecting both stress and depression. Using a sample of identical and fraternal twins, this study explores genetic influences on depression and assorted sources of stress while explicitly estimating, and thereby controlling for, gene-environment correlations. I consider both stress and depression in a fine-grained fashion. For the former, the study explores assorted sources of stress, including health and disability, family, unemployment, discrimination, and perceived neighborhood safety, as gene-environment correlations may be stronger for some forms of stress than others. For the latter, the study explores both depressive symptoms and major depressive disorders, as each may entail a different epidemiological process, especially with respect to genes. The results reveal that most, but not all, measures of stress have moderate heritabilities, suggesting that genes influence exposure to the environment in a broad fashion. Yet, despite this, the relationship between stress and depression is generally robust to gene-environment correlations. There are some notable exceptions. For example, allowing for gene-environment correlations, marital conflict is generally unrelated to depression. Moreover, gene-environment correlations are generally stronger for major depression than for depressive symptoms, encouraging further elaboration of the distinction between the onset of depression and its recurrence, especially in the context of genes. These exceptions do not put limits on environmental influence, but do suggest that genes operate in a complex life-course fashion. PMID:20943587

Schnittker, Jason

2010-09-01

4

Commentary: Missing heritability, polygenic scores, and gene-environment correlation.  

PubMed

This special issue amply fulfils its aim of moving the study of gene × environment (GE) interplay forward constructively and creatively, exploiting contributions from diverse disciplines. Rather than discussing the many interesting findings and methods in this special issue, I will comment on two cross-cutting issues - one about genes and the other about the environment - that came to mind as I read these articles. PMID:24007418

Plomin, Robert

2013-10-01

5

Effects of the Family Environment: Gene-Environment Interaction and Passive Gene-Environment Correlation  

ERIC Educational Resources Information Center

|The classical twin study provides a useful resource for testing hypotheses about how the family environment influences children's development, including how genes can influence sensitivity to environmental effects. However, existing statistical models do not account for the possibility that children can inherit exposure to family environments…

Price, Thomas S.; Jaffee, Sara R.

2008-01-01

6

Specification, testing, and interpretation of gene-by-measured-environment interaction models in the presence of gene-environment correlation  

PubMed Central

Purcell (2002) proposed a bivariate biometric model for testing and quantifying the interaction between latent genetic influences and measured environments in the presence of gene-environment correlation. Purcell’s model extends the Cholesky model to include gene-environment interaction. We examine a number of closely-related alternative models that do not involve gene-environment interaction but which may fit the data as well Purcell’s model. Because failure to consider these alternatives could lead to spurious detection of gene-environment interaction, we propose alternative models for testing gene-environment interaction in the presence of gene-environment correlation, including one based on the correlated factors model. In addition, we note mathematical errors in the calculation of effect size via variance components in Purcell’s model. We propose a statistical method for deriving and interpreting variance decompositions that are true to the fitted model.

Rathouz, Paul J.; Van Hulle, Carol A.; Lee Rodgers, Joseph; Waldman, Irwin D.; Lahey, Benjamin B.

2009-01-01

7

The role of gene-environment correlations and interactions in middle childhood depressive symptoms.  

PubMed

Depression is known to be associated with a wide array of environmental factors. Such associations are due at least in part to genetic influences on both. This issue has been little explored with preadolescent children. Measures of family chaos and parenting style at age 9 and child depressive symptoms at age 12 were completed by 3,258 twin pairs from the Twins Early Development Study and their parents. Quantitative genetic modeling was used to explore common and unique genetic and environmental influences on both family environment and later depressive symptoms. Depressive symptoms at age 12 were significantly heritable. Moderate genetic effects influenced parenting style and family chaos at the age of 9, indicating gene-environment correlation. There were significant genetic correlations between family environment and depressive symptoms. There was some evidence of a Gene × Environment interaction, with stronger genetic effects on depressive symptoms for children with more suboptimal family environment. There was an Environment × Environment interaction, with effects of nonshared environment on depressive symptoms stronger for twins with more adverse parenting experiences. There is some evidence for gene-environment correlation between aspects of family environment in middle childhood and subsequent depressive symptoms. This suggests that one of the mechanisms by which genes lead to depressive symptoms may be by themselves influencing depressogenic environments. PMID:23398755

Wilkinson, Paul O; Trzaskowski, Maciej; Haworth, Claire M A; Eley, Thalia C

2013-02-01

8

A review of gene-environment correlations and their implications for autism: a conceptual model.  

PubMed

A conceptual model is proposed that explains how gene-environment correlations and the multiplier effect function in the context of social development in individuals with autism. The review discusses the current state of autism genetic research, including its challenges, such as the genetic and phenotypic heterogeneity of the disorder, and its limitations, such as the lack of interdisciplinary work between geneticists and social scientists. We discuss literature on gene-environment correlations in the context of social development and draw implications for individuals with autism. The review expands upon genes, behaviors, types of environmental exposure, and exogenous variables relevant to social development in individuals on the autism spectrum, and explains these factors in the context of the conceptual model to provide a more in-depth understanding of how the effects of certain genetic variants can be multiplied by the environment to cause largely phenotypic individual differences. Using the knowledge gathered from gene-environment correlations and the multiplier effect, we outline novel intervention directions and implications. PMID:23915084

Meek, Shantel E; Lemery-Chalfant, Kathryn; Jahromi, Laudan B; Valiente, Carlos

2013-07-01

9

Gene-environment correlation: difficulties and a natural experiment-based strategy.  

PubMed

Objectives. We explored how gene-environment correlations can result in endogenous models, how natural experiments can protect against this threat, and if unbiased estimates from natural experiments are generalizable to other contexts. Methods. We compared a natural experiment, the College Roommate Study, which measured genes and behaviors of college students and their randomly assigned roommates in a southern public university, with observational data from the National Longitudinal Study of Adolescent Health in 2008. We predicted exposure to exercising peers using genetic markers and estimated environmental effects on alcohol consumption. A mixed-linear model estimated an alcohol consumption variance that was attributable to genetic markers and across peer environments. Results. Peer exercise environment was associated with respondent genotype in observational data, but not in the natural experiment. The effects of peer drinking and presence of a general gene-environment interaction were similar between data sets. Conclusions. Natural experiments, like random roommate assignment, could protect against potential bias introduced by gene-environment correlations. When combined with representative observational data, unbiased and generalizable causal effects could be estimated. PMID:23927502

Wagner, Brandon; Li, Jiang; Liu, Hexuan; Guo, Guang

2013-08-08

10

Child dopamine active transporter 1 genotype and parenting: evidence for evocative gene-environment correlations.  

PubMed

The dopamine active transporter 1 (DAT1) gene is implicated in psychopathology risk. Although the processes by which this gene exerts its effects on risk are poorly understood, a small body of research suggests that the DAT1 gene influences early emerging negative emotionality, a marker of children's psychopathology risk. As child negative emotionality evokes negative parenting practices, the DAT1 gene may also play a role in gene-environment correlations. To test this model, children (N = 365) were genotyped for the DAT1 gene and participated in standardized parent-child interaction tasks with their primary caregiver. The DAT1 gene 9-repeat variant was associated with child negative affect expressed toward the parent during parent-child interactions, and parents of children with a 9-repeat allele exhibited more hostility and lower guidance/engagement than parents of children without a 9-repeat allele. These gene-environment associations were partially mediated by child negative affect toward the parent. The findings implicate a specific polymorphism in eliciting negative parenting, suggesting that evocative associations play a role in elevating children's risk for emotional trajectories toward psychopathology risk. PMID:23398760

Hayden, Elizabeth P; Hanna, Brigitte; Sheikh, Haroon I; Laptook, Rebecca S; Kim, Jiyon; Singh, Shiva M; Klein, Daniel N

2013-02-01

11

The dopamine D2 receptor gene and depressive and anxious symptoms in childhood: associations and evidence for gene-environment correlation and gene-environment interaction  

PubMed Central

Objectives Research implicates the A1 allele of the dopamine D2 receptor gene (DRD2) Taq1A polymorphism in the development of depression and anxiety. Furthermore, recent papers suggest that children with A1 allele of this gene may receive less positive parenting, and that the effects of this gene on child symptoms may be moderated by parenting. We sought to replicate and extend these findings using behavioral measures in a nonclinical sample of young children. Methods In a sample of 473 preschool-aged children and their mothers, structured clinical interview measures and maternal reports of child symptoms were collected, and standardized observations of parent–child interactions were conducted. Results An association was detected between the DRD2 A1 allele and symptoms of depression and anxiety indexed using interview and parent report methods. As found in previous reports, children with the DRD2 A1 allele received less supportive parenting and displayed higher levels of negative emotionality during parent–child interactions. Tests of mediation and moderation were conducted. Conclusion We found associations between the DRD2 A1 allele and early-emerging anxious and depressive symptoms in a community sample of preschool-aged children, and evidence of a gene–environment correlation and moderation of the main effect of child genotype on child symptoms by parenting.

Hayden, Elizabeth P.; Klein, Daniel N.; Dougherty, Lea R.; Olino, Thomas M.; Laptook, Rebecca S.; Dyson, Margaret W.; Bufferd, Sara J.; Durbin, C. Emily; Sheikh, Haroon I.; Singh, Shiva M.

2012-01-01

12

Evocative gene-environment correlation in the mother-child relationship: a twin study of interpersonal processes.  

PubMed

The behavior genetic literature suggests that genetically influenced characteristics of the child elicit specific behaviors from the parent. However, little is known about the processes by which genetically influenced child characteristics evoke parental responses. Interpersonal theory provides a useful framework for identifying reciprocal behavioral processes between children and mothers. The theory posits that, at any given moment, interpersonal behavior varies along the orthogonal dimensions of warmth and control and that the interpersonal behavior of one individual tends to elicit corresponding or contrasting behavior from the other (i.e., warmth elicits warmth, whereas control elicits submission). The current study thus examined these dimensions of interpersonal behavior as they relate to the parent-child relationship in 546 twin families. A computer joystick was used to rate videos of mother-child interactions in real time, yielding information on mother and child levels of warmth and control throughout the interaction. Analyses indicated that maternal control, but not maternal warmth, was influenced by evocative gene-environment correlational processes, such that genetic influences on maternal control and child control were largely overlapping. Moreover, these common genetic influences were present both cross-sectionally and over the course of the interaction. Such findings not only confirm the presence of evocative gene-environment correlational processes in the mother-child relationship but also illuminate at least one of the specific interpersonal behaviors that underlie this evocative process. PMID:23398756

Klahr, Ashlea M; Thomas, Katherine M; Hopwood, Christopher J; Klump, Kelly L; Burt, S Alexandra

2013-02-01

13

The Heritability of Personality is not Always 50%: Gene-Environment Interactions and Correlations between Personality and Parenting  

PubMed Central

Twin studies of personality are consistent in attributing approximately half of the variance in personality to genetic effects, with the remaining variance attributed to environments that make people within the same families different. Such conclusions, however, are based on quantitative models of human individual differences that estimate genetic and environmental contributions as constants for entire populations. Recent advances in statistical modeling allow for the possibility of estimating genetic and environmental contributions contingent on other variables, allowing the quantification of phenomena that have traditionally been characterized as gene-environment interaction and correlation. We applied these newer models to understand how adolescents’ descriptions of their relationships with their parents might change or moderate the impact of genetic and environmental factors on personality. We documented notable moderation in the domains of positive and negative emotionality, with parental relationships acting to both enhance and diminish both genetic and environmental effects. We discuss how genetic and environmental contributions to personality might be more richly conceptualized as dynamic systems of gene-environment interplay – systems that are not captured by classical concepts, such as the overall heritability of personality.

Krueger, Robert F.; South, Susan; Johnson, Wendy; Iacono, William

2008-01-01

14

Evidence of gene-environment correlation for peer difficulties: disruptive behaviors predict early peer relation difficulties in school through genetic effects.  

PubMed

Early disruptive behaviors, such as aggressive and hyperactive behaviors, known to be influenced by genetic factors, have been found to predict early school peer relation difficulties, such as peer rejection and victimization. However, there is no consensus regarding the developmental processes underlying this predictive association. Genetically informative designs, such as twin studies, are well suited for investigating the underlying genetic and environmental etiology of this association. The main goal of the present study was to examine the possible establishment of an emerging gene-environment correlation linking disruptive behaviors to peer relationship difficulties during the first years of school. Participants were drawn from an ongoing longitudinal study of twins who were assessed with respect to their social behaviors and their peer relation difficulties in kindergarten and in Grade 1 through peer nominations measures and teacher ratings. As predicted, disruptive behaviors were concurrently and predictively associated with peer relation difficulties. Multivariate analyses of these associations indicate that they were mainly accounted for by genetic factors. These results emphasize the need to adopt an early and persistent prevention framework targeting both the child and the peer context to alleviate the establishment of a negative coercive process and its consequences. PMID:23398754

Boivin, Michel; Brendgen, Mara; Vitaro, Frank; Forget-Dubois, Nadine; Feng, Bei; Tremblay, Richard E; Dionne, Ginette

2013-02-01

15

Entropy-Based Information Gain Approaches to Detect and to Characterize Gene-Gene and Gene-Environment Interactions/Correlations of Complex Diseases  

PubMed Central

For complex diseases, the relationship between genotypes, environment factors and phenotype is usually complex and nonlinear. Our understanding of the genetic architecture of diseases has considerably increased over the last years. However, both conceptually and methodologically, detecting gene-gene and gene-environment interactions remains a challenge, despite the existence of a number of efficient methods. One method that offers great promises but has not yet been widely applied to genomic data is the entropy-based approach of information theory. In this paper we first develop entropy-based test statistics to identify 2-way and higher order gene-gene and gene-environment interactions. We then apply these methods to a bladder cancer data set and thereby test their power and identify strengths and weaknesses. For two-way interactions, we propose an information-gain approach based on mutual information. For three-ways and higher order interactions, an interaction-information-gain approach is used. In both case we develop one-dimensional test statistics to analyze sparse data. Compared to the naive chi-square test, the test statistics we develop have similar or higher power and is robust. Applying it to the bladder cancer data set allowed to investigate the complex interactions between DNA repair gene SNPs, smoking status, and bladder cancer susceptibility. Although not yet widely applied, entropy-based approaches appear as a useful tool for detecting gene-gene and gene-environment interactions. The test statistics we develop add to a growing body methodologies that will gradually shed light on the complex architecture of common diseases.

Fan, R; Zhong, M; Wang, S; Zhang, Y; Andrew, A; Karagas, M; Chen, H; Amos, CI; Xiong, M; Moore, J

2011-01-01

16

Dead time behaviors in passive neutron correlation counting  

SciTech Connect

Passive Neutron Coincidence Counting (PNCC) and Passive Neutron Multiplicity Counting (PNMC) based on (Multiplicity) Shift Register (M)(SR) pulse train correlation analyzers is a long established and important non destructive assay method used in the quantification of plutonium and other spontaneously fissile materials across the fuel cycle. Very high efficiency neutron chambers (>60%) are now available and are being applied to ever more demanding items including impure materials with a high ({alpha}, n) rate and articles with a high self-leakage multiplication. This trend means that high instantaneous count rates are commonly encountered such that the multiplicity histogram extends to high order; in other words the number of events detected in a single coincidence gate can be large. This poses a problem in that the likelihood of accidental (chance) coincidences due to random events and overlapping (super) fission histories increases and precision is lost in correcting for them. The epithermal design is one attempt to reduce the capture time distribution to minimize the accidentals coincidence rate but the field of application is so broad that high instantaneous rates are still encountered. This inevitably results in the need to apply a correction to the observed Singles, Doubles and Triples rate for dead time losses. When the instantaneous counting rate is high the uncertainties in the applied corrections can be the accuracy limiting factor in the derived counting rate. Controlling and compensating for dead time losses so that target accuracy is achieved is a crucial aspect of a successful design and implementation process. Dead time losses can be reduced substantially on new systems intended for special use by using dedicated preamplifier-discriminators for each {sup 3}He-filled proportional counter together with de-randomiser circuitry and fast encoding electronics. These adaptations are costly, however, and may be difficult to retrofit to existing systems. In this work we therefore take a fresh look at the way in which corrections for dead time losses are applied to the recorded MSR data. We note several interesting empirical correlations observed in experimental data which allow dead time parameters to be extracted. We also comment on the self consistency constraints which exist and can be exploited between PNCC and PNMC results and also between expressions for the correlated rates derived from the random triggered and signal triggered histograms respectively. (authors)

Croft, S.; McElroy, R.D.; Philips, S.; Villani, M.F. [Canberra Industries Inc., Meriden, CT (United States); Evans, L.G. [Birmingham Univ., School of Physics and Astronomy (United Kingdom)

2007-07-01

17

Operating characteristics of alternative statistical methods for detecting gene-by-measured environment interaction in the presence of gene-environment correlation in twin and sibling studies.  

PubMed

It is likely that all complex behaviors and diseases result from interactions between genetic vulnerabilities and environmental factors. Accurately identifying such gene-environment interactions is of critical importance for genetic research on health and behavior. In a previous article we proposed a set of models for testing alternative relationships between a phenotype (P) and a putative moderator (M) in twin studies. These include the traditional bivariate Cholesky model, an extension of that model that allows for interactions between M and the underling influences on P, and a model in which M has a non-linear main effect on P. Here we use simulations to evaluate the type I error rates, power, and performance of the Bayesian Information Criterion under a variety of data generating mechanisms and samples sizes (n = 2,000 and n = 500 twin pairs). In testing the extension of the Cholesky model, false positive rates consistently fell short of the nominal Type I error rates ([Formula: see text]). With adequate sample size (n = 2,000 pairs), the correct model had the lowest BIC value in nearly all simulated datasets. With lower sample sizes, models specifying non-linear main effects were more difficult to distinguish from models containing interaction effects. In addition, we provide an illustration of our approach by examining possible interactions between birthweight and the genetic and environmental influences on child and adolescent anxiety using previously collected data. We found a significant interaction between birthweight and the genetic and environmental influences on anxiety. However, the interaction was accounted for by non-linear main effects of birthweight on anxiety, verifying that interaction effects need to be tested against alternative models. PMID:23090766

Van Hulle, Carol A; Lahey, Benjamin B; Rathouz, Paul J

2012-10-23

18

Operating characteristics of alternative statistical methods for detecting gene-by-measured environment interaction in the presence of gene-environment correlation in twin and sibling studies  

PubMed Central

It is likely that all complex behaviors and diseases result from interactions between genetic vulnerabilities and environmental factors. Accurately identifying such gene-environment interactions is of critical importance for genetic research on health and behavior. In a previous article we proposed a set of models for testing alternative relationships between a phenotype (P) and a putative moderator (M) in twin studies. These include the traditional bivariate Cholesky model, an extension of that model that allows for interactions between M and the underling influences on P, and a model in which M has a non-linear main effect on P. Here we use simulations to evaluate the type I error rates, power, and performance of the Bayesian Information Criterion under a variety of data generating mechanisms and samples sizes (n=2000 and n=500 twin pairs). In testing the extension of the Cholesky model, false positive rates consistently fell short of the nominal Type I error rates (?=.10, .05, .01). With adequate sample size (n=2000 pairs), the correct model had the lowest BIC value in nearly all simulated datasets. With lower sample sizes, models specifying non-linear main effects were more difficult to distinguish from models containing interaction effects. In addition, we provide an illustration of our approach by examining possible interactions between birthweight and the genetic and environmental influences on child and adolescent anxiety using previously collected data. We found a significant interaction between birthweight and the genetic and environmental influences on anxiety. However, the interaction was accounted for by non-linear main effects of birthweight on anxiety, verifying that interaction effects need to be tested against alternative models.

Van Hulle, Carol A.; Lahey, Benjamin B.; Rathouz, Paul J.

2012-01-01

19

Genes, Environment, and Human Behavior.  

ERIC Educational Resources Information Center

|This curriculum module explores genes, environment, and human behavior. This book provides materials to teach about the nature and methods of studying human behavior, raise some of the ethical and public policy dilemmas emerging from the Human Genome Project, and provide professional development for teachers. An extensive Teacher Background…

Bloom, Mark V.; Cutter, Mary Ann; Davidson, Ronald; Dougherty, Michael J.; Drexler, Edward; Gelernter, Joel; McCullough, Laurence B.; McInerney, Joseph D.; Murray, Jeffrey C.; Vogler, George P.; Zola, John

20

Correlation of passivity symptoms and dysfunctional visuomotor action monitoring in psychosis  

PubMed Central

Passivity experiences are hallmark symptoms of schizophrenia that can be characterized by the belief that one's thoughts or actions are controlled by an external agent. It has recently been suggested that these psychotic experiences result from defective monitoring of one's own actions, i.e. disturbed comparison of actions and perceived outcomes. In this study, we examined the function of the previously characterized action monitoring network of the inferior parietal lobule (IPL), medial (mPFC) and lateral prefrontal cortices in patients with different levels of passivity symptoms with an fMRI task. The visuomotor fMRI task demanded control of visually perceived object movements by alternating button presses with the left and the right index finger. In the monitoring condition of this task subjects stopped their actions whenever they detected visuomotor incongruence. fMRI and behavioural data from 15 patients were tested for correlation with passivity symptoms using standardized Scale for Assessment of Positive Symptoms (SAPS)- and AMDP- passivity symptom ratings. Both types of data were tested for differences between the patients group and 15 healthy controls. In the patient group we found the expected correlation of passivity symptoms and visuomotor monitoring performance. There was a significant positive correlation of passivity symptoms with increased latency of incongruence detection and a negative correlation of SAPS-passivity with the number of detected events. fMRI data revealed correlations of passivity symptoms with activation in bilateral IPL, primary motor and sensory cortices in the action monitoring condition. A correlation of passivity symptoms with the main experimental effect (actions with – actions without monitoring) was found in the posterior cingulate cortex (PCC) and in the left IPL. No group differences or group by task interactions were found within the visuomotor-action-monitoring network. Our results demonstrate the association between passivity symptoms and the dysfunction of visuomotor action monitoring and support the idea that psychotic passivity experiences result from dysfunctions of central action monitoring mechanisms: According to pre-existing concepts of parietal cortex function, IPL-hyperactivation may represent an increase in false detections of visuomotor incongruence while the correlation between passivity and the differential effect of monitoring on PCC-activation assumedly represents greater self-monitoring effort in passivity experiences.

Heekeren, Karsten; Daumann, Jorg; Schnell, Thomas; Schnitker, Ralph; Moller-Hartmann, Walter; Gouzoulis-Mayfrank, Euphrosyne

2008-01-01

21

Gene-Environment Interplay, Family Relationships, and Child Adjustment  

ERIC Educational Resources Information Center

|This paper reviews behavioral genetic research from the past decade that has moved beyond simply studying the independent influences of genes and environments. The studies considered in this review have instead focused on understanding gene-environment interplay, including genotype-environment correlation (rGE) and genotype x environment…

Horwitz, Briana N.; Neiderhiser, Jenae M.

2011-01-01

22

Gene-Environment Interplay, Family Relationships, and Child Adjustment  

ERIC Educational Resources Information Center

This paper reviews behavioral genetic research from the past decade that has moved beyond simply studying the independent influences of genes and environments. The studies considered in this review have instead focused on understanding gene-environment interplay, including genotype-environment correlation (rGE) and genotype x environment…

Horwitz, Briana N.; Neiderhiser, Jenae M.

2011-01-01

23

An expert system for correlation of radar and passive sensor signals  

SciTech Connect

This paper describes a system for automating the correlation task by combining high-speed hardware with symbolic pattern-matching software to perform correlation of active and passive signals in real time. The first section of this paper describes the hardware and software used to implement the inference engine so that correlations can be performed in real time. The second section describes the expert system, with emphasis on the heuristics used to code the correlator efficiently. The final section describes the simulation environment under which the system is operated current efforts, and plans for further development. 2 refs., 2 figs.

Williams, L.C.; Gamberini, R.J.

1989-01-01

24

Statistics for Testing Gene–Environment Interaction  

Microsoft Academic Search

\\u000a This chapter introduces a number of new gene–environment interaction measures and develop novel statistics that are based\\u000a on these new gene–environment interaction measures. These new statistics are simple, less computationally intensive and easy\\u000a to implement. It is hoped that these developments may open a new avenue for large-scale genome-wide gene–environment interaction\\u000a analysis, deciphering the genetic and physiological meaning of gene–environment

Momiao Xiong; Xuesen Wu

25

GENERAL: Influence of velocity spatiotemporal correlations on the anomalous scaling exponents of passive scalars  

NASA Astrophysics Data System (ADS)

In this paper, we consider spatial-temporal correlation functions of the turbulent velocities. With numerical simulations on the Gledzer-Ohkitani-Yamada (GOY) shell model, we show that the correlation function decays exponentially. The advecting velocity field is regarded as a colored noise field, which is spatially and temporally correlative. For comparison, we are also given the scaling exponents of passive scalars obtained by the Gaussian random velocity field, the multi-dimensional normal velocity field and the She-Leveque velocity field, introduced by She, et al. We observe that extended self-similarity scaling exponents H(p)/H(2) of passive scalar obtained by the colored noise field are more anomalous than those obtained by the other three velocity fields.

Zhang, Xiao-Qiang; Wang, Guang-Rui; Chen, Shi-Gang

2009-12-01

26

Gene-Environment Processes Linking Aggression, Peer Victimization, and the Teacher-Child Relationship  

ERIC Educational Resources Information Center

|Aggressive behavior in middle childhood is at least partly explained by genetic factors. Nevertheless, estimations of simple effects ignore possible gene-environment interactions (G x E) or gene-environment correlations (rGE) in the etiology of aggression. The present study aimed to simultaneously test for G x E and rGE processes between…

Brendgen, Mara; Boivin, Michel; Dionne, Ginette; Barker, Edward D.; Vitaro, Frank; Girard, Alain; Tremblay, Richard; Perusse, Daniel

2011-01-01

27

Gene - Environment Interplay, Family Relationships, and Child Adjustment.  

PubMed

This paper reviews behavioral genetic research from the past decade that has moved beyond simply studying the independent influences of genes and environments. The studies considered in this review have instead focused on understanding gene - environment interplay, including genotype - environment correlation ( rGE) and genotype × environment interaction (G × E). Studies have suggested that rGE is an important pathway through which family relationships are associated with child adjustment. Also important are direct causal influences of family relationships on child adjustment, independent of genetic confounds. Other studies have indicated that genetic and environmental influences on child adjustment are moderated by different levels of family relationships in G × E interactions. Genetically informed studies that have examined family relations have been critical to advancing our understanding of gene - environment interplay. PMID:22162877

Horwitz, Briana N; Neiderhiser, Jenae M

2011-08-01

28

Gene - Environment Interplay, Family Relationships, and Child Adjustment  

PubMed Central

This paper reviews behavioral genetic research from the past decade that has moved beyond simply studying the independent influences of genes and environments. The studies considered in this review have instead focused on understanding geneenvironment interplay, including genotype – environment correlation ( rGE) and genotype × environment interaction (G × E). Studies have suggested that rGE is an important pathway through which family relationships are associated with child adjustment. Also important are direct causal influences of family relationships on child adjustment, independent of genetic confounds. Other studies have indicated that genetic and environmental influences on child adjustment are moderated by different levels of family relationships in G × E interactions. Genetically informed studies that have examined family relations have been critical to advancing our understanding of geneenvironment interplay.

Horwitz, Briana N.; Neiderhiser, Jenae M.

2011-01-01

29

Gene-Environment Interactions on Growth Trajectories  

PubMed Central

It has been suggested that children with larger brains tend to perform better on IQ tests or cognitive function tests. Prenatal head growth and head growth in infancy are two crucial periods for subsequent intelligence. Studies have shown that environmental exposure to air pollutants during pregnancy is associated with fetal growth reduction, developmental delay, and reduced IQ. Meanwhile, genetic polymorphisms may modify the effect of environment on head growth. However, studies on gene–environment or gene–gene interactions on growth trajectories have been quite limited partly due to the difficulty to quantitatively measure interactions on growth trajectories. Moreover, it is known that assessing the significance of gene–environment or gene–gene interactions on cross-sectional outcomes empirically using the permutation procedures may bring substantial errors in the tests. We proposed a score that quantitatively measures interactions on growth trajectories and developed an algorithm with a parametric bootstrap procedure to empirically assess the significance of the interactions on growth trajectories under the likelihood framework. We also derived a Wald statistic to test for interactions on growth trajectories and compared it to the proposed parametric bootstrap procedure. Through extensive simulation studies, we demonstrated the feasibility and power of the proposed testing procedures. We applied our method to a real dataset with head circumference measures from birth to age 7 on a cohort currently being conducted by the Columbia Center for Children's Environmental Health (CCCEH) in Krakow, Poland, and identified several significant gene–environment interactions on head circumference growth trajectories.

Wang, Shuang; Xiong, Wei; Ma, Weiping; Chanock, Stephen; Jedrychowski, Wieslaw; Wu, Rongling; Perera, Frederica P.

2012-01-01

30

Dietary and lifestyle correlates of passive smoking in Hong Kong, Japan, Sweden, and the U.S.A  

Microsoft Academic Search

From epidemiologic studies in several countries, passive smoking has been associated with increased risk for lung cancer, respiratory diseases, and coronary heart disease. Since the relative risks derived from those studies are weak, i.e. relative risk less than two, we investigated whether poorer diets and less healthy lifestyles might act as confounders and be correlated with having a smoking husband

Linda C. Koo; Geoffrey C. Kabat; Ragnar Rylander; Suketami Tominaga; Ikuko Kato; John H. C. Ho

1997-01-01

31

The neural correlates of ego-disturbances (passivity phenomena) and formal thought disorder in schizophrenia  

Microsoft Academic Search

Ego-disturbances (passivity phenomena) and formal thought disorder are two hallmark symptoms of schizophrenia. Formal thought\\u000a disorder has been highlighted already very early by Eugen Bleuler in his concept of basic symptoms (Grundsymptome). In contrast\\u000a ego-disturbances (Ich-Störungen) or passivity phenomena have been declared as core symptoms of schizophrenia by Kurt Schneider\\u000a in his concept of first-rank symptoms (Erstrangsymptome) that influenced the

Dirk Leube; Carin Whitney; Tilo Kircher

2008-01-01

32

Gene–Environment Interaction: Definitions and Study Design  

Microsoft Academic Search

Study of gene–environment interaction is important for improving accuracy and precision in the assessment of both genetic and environmental influences. This overview presents a simple definition of gene–environment interaction and suggests study designs for detecting it. Gene–environment interaction is defined as “a different effect of an environmental exposure on disease risk in persons with different genotypes,” or, alternatively, “a different

Ruth Ottman

1996-01-01

33

The role of individual correlates and class norms in defending and passive bystanding behavior in bullying: a multilevel analysis.  

PubMed

This study investigates possible individual and class correlates of defending and passive bystanding behavior in bullying, in a sample of 1,825 Italian primary school (mean age=10 years 1 month) and middle school (mean age=13 years 2 months) students. The findings of a series of multilevel regression models show that both individual (e.g., provictim attitudes and perceived peer pressure for intervention) and class characteristics (e.g., class provictim attitudes, peer injunctive norms, and descriptive norms) help explain defending and passive bystanding behavior in bullying. These results significantly expand previous findings in this field, by demonstrating the need for a social-ecological approach to the study of the different aspects of bullying. Implications for antibullying programs are discussed. PMID:22880944

Pozzoli, Tiziana; Gini, Gianluca; Vieno, Alessio

2012-08-07

34

Gene-environment interactions in geriatric depression  

PubMed Central

Risk for the development of major depressive disorder (MDD) is likely influenced by an interacting set of genes and environments. Many elderly are exposed to a variety of potential MDD precipitants. Medical co-morbidities, high inflammatory states, care-giver stress, and cerebrovascular changes are often observed proximal to the development of an episode. Additionally, some adults have histories of exposure to environmental stressors such as early life traumas that may result in a life-long predisposition to MDD. Despite these exposures, many people do not develop MDD; and genetic influences are hypothesized to be one influence on vulnerability and resilience. Over the last seven years, several studies have examined a variety of genes for this gene × environment (G×E) interaction. Most have examined a length polymorphism in the promoter region for the serotonin transporter gene, but some have examined brain derived neurotrophic factor, various genes encoding for key players in the hypothalamic-pituitary-adrenal axis, as well as other genes involved in the monoaminergic, neuroendocrine, and inflammatory systems. There is marked variation in the design of these studies, as well as in the measures of environment, MDD, and genotyping. Interpreting the sometimes inconsistent findings among studies is complicated by this heterogeneity. However, some tentative trends have emerged. An overview is provided of both the methodologies and results of these studies, noting consistent trends as well as confounds. The progress made to date will hopefully inform the next generation of studies.

Lotrich, Francis E.

2011-01-01

35

Gene–Environment Interaction in Yeast Gene Expression  

Microsoft Academic Search

The effects of genetic variants on phenotypic traits often depend on environmental and physiological conditions, but such gene-environment interactions are poorly understood. Recently developed approaches that treat transcript abundances of thousands of genes as quantitative traits offer the opportunity to broadly characterize the architecture of gene-environment interactions. We examined the genetic and molecular basis of variation in gene expression between

Erin N. Smith; Leonid Kruglyak

2008-01-01

36

Gene-Environment Interactions in Human Disease: Nuisance or Opportunity?  

PubMed Central

Many environmental risk factors for common, complex human diseases have been revealed by epidemiologic studies, but how genotypes at specific loci modulate individual responses to environmental risk factors is largely unknown. Gene-environment interactions will be missed in genome-wide association studies and may account for some of the ‘missing heritability’ for these diseases. In this review, we focus on asthma as a model disease for studying gene-environment interactions because of relatively large numbers of candidate gene-environment interactions with asthma risk in the literature. Identifying these interactions using genome-wide approaches poses formidable methodological problems and elucidating molecular mechanisms for these interactions has been challenging. We suggest that studying gene-environment interactions in animal models, while more tractable, is not likely to shed light on the genetic architecture of human diseases. Lastly, we propose avenues for future studies to find gene-environment interactions.

Ober, Carole; Vercelli, Donata

2010-01-01

37

Gene-environment interaction and the genetics of depression  

PubMed Central

Depression is a group of brain disorders with varied origins, complex genetics and obscure neurobiology. Definitions of clinical phenotypes are not rooted in their neurobiology, and animal models of behavioural despair have considerable limitations. Nevertheless, investigation of subtle alterations in gene expression, of correlations between genotype and brain activity, and of environmental variables interacting with genetic variants have advanced research into the genetics of depression. Although the postgenomic era is still in its infancy, several milestones have already been reached: variation in gene expression has been confirmed to play a predominant role in individual differences; gene–environment interactions have been established in humans and in a nonhuman primate model; gene–phenotype correlations have been substantiated by functional neuroimaging; and the notion of gene networks that control brain development is increasingly recognized. Given the etiologic and psychobiologic complexity of mood disorders, it is not surprising that the identification of specific genetic factors is extremely difficult and continues to be among the last frontiers of gene hunting.

Lesch, Klaus Peter

2004-01-01

38

Gene-Environment Interaction in Psychological Traits and Disorders  

PubMed Central

There has been an explosion of interest in studying gene-environment interactions (GxE) as they relate to the development of psychopathol-ogy. In this article, I review different methodologies to study gene-environment interaction, providing an overview of methods from animal and human studies and illustrations of gene-environment interactions detected using these various methodologies. Gene-environment interaction studies that examine genetic influences as modeled latently (e.g., from family, twin, and adoption studies) are covered, as well as studies of measured genotypes. Importantly, the explosion of interest in gene-environment interactions has raised a number of challenges, including difficulties with differentiating various types of interactions, power, and the scaling of environmental measures, which have profound implications for detecting gene-environment interactions. Taking research on gene-environment interactions to the next level will necessitate close collaborations between psychologists and geneticists so that each field can take advantage of the knowledge base of the other.

Dick, Danielle M.

2013-01-01

39

The nature of nurture: disentangling passive genotype-environment correlation from family relationship influences on children's externalizing problems.  

PubMed

The relationship between interparental conflict, hostile parenting, and children's externalizing problems is well established. Few studies, however, have examined the pattern of association underlying this constellation of family and child level variables while controlling for the possible confounding presence of passive genotype-environment correlation. Using the attributes of 2 genetically sensitive research designs, the present study examined associations among interparental conflict, parent-to-child hostility, and children's externalizing problems among genetically related and genetically unrelated mother-child and father-child groupings. Analyses were conducted separately by parent gender, thereby allowing examination of the relative role of the mother-child and father-child relationships on children's behavioral outcomes. Path analyses revealed that for both genetically related and genetically unrelated parents and children, indirect associations were apparent from interparental conflict to child externalizing problems through mother-to-child and father-to-child hostility. Associations between interparental conflict and parent-to-child hostility across genetically related and genetically unrelated parent-child groupings were significantly stronger for fathers compared to mothers. Results are discussed with respect to the role of passive genotype-environment correlation as a possible confounding influence in interpreting research findings from previous studies conducted in this area. Implications for intervention programs focusing on family process influences on child externalizing problems are also considered. PMID:23421830

Harold, Gordon T; Leve, Leslie D; Elam, Kit K; Thapar, Anita; Neiderhiser, Jenae M; Natsuaki, Misaki N; Shaw, Daniel S; Reiss, David

2013-02-01

40

Calibration of Passive Microwave Polarimeters that Use Hybrid Coupler-Based Correlators.  

National Technical Information Service (NTIS)

Four calibration algorithms are studied for microwave polarimeters that use hybrid coupler-based correlators: (1) conventional two-look of hot and cold sources, (2) three looks of hot and cold source combinations, (3) two-look with correlated source, and ...

J. R. Piepmeier

2003-01-01

41

Pseudoelastic SMA Spring Elements for Passive Vibration Isolation: Part II - Simulations and Experimental Correlations.  

National Technical Information Service (NTIS)

In Part II of this two-part study, system simulations and experimental correlations of a Shape Memory Alloy (SMA) based vibration isolation device (briefly described in Part I) has been presented. This device consists of layers of pre-constrained SMA tube...

D. C. Lagoudas M. M. Khan J. J. Mayes B. K. Henderson

2004-01-01

42

Pseudoelastic SMA Spring Elements for Passive Vibration Isolation: Part II – Simulations and Experimental Correlations  

Microsoft Academic Search

In Part II of this two-part study, system simulations and experimental correlations of a Shape Memory Alloy (SMA) based vibration isolation device (briefly described in Part I) has been presented. This device consists of layers of preconstrained SMA tubes undergoing pseudoelastic transformations under transverse dynamical loading. In Part II, detailed description of the prototype vibration isolation device, its experimental setup,

Dimitris C. Lagoudas; Mughees M. Khan; John J. Mayes; Benjamin K. Henderson

2004-01-01

43

PSEUDOELASTIC SMA SPRING ELEMENTS FOR PASSIVE VIBRATION ISOLATION, PART II: SIMULATIONS AND EXPERIMENTAL CORRELATIONS  

Microsoft Academic Search

In part II of this two-part study, system simulations and ex- perimental correlations of an SMA based vibration isolation de- vice (briefly described in part I) has been presented. This de- vice consists of layers of pre-constrained SMA tubes undergoing pseudoelastic transformations under transverse dynamical load- ing. In part II, detailed description of the prototype vibration iso- lation device, its

Dimitris C. Lagoudas; Mughees M. Khan; John J. Mayes; Benjamin K. Henderson

2003-01-01

44

Information-Theoretic Metrics for Visualizing Gene-Environment Interactions  

PubMed Central

The purpose of our work was to develop heuristics for visualizing and interpreting gene-environment interactions (GEIs) and to assess the dependence of candidate visualization metrics on biological and study-design factors. Two information-theoretic metrics, the k-way interaction information (KWII) and the total correlation information (TCI), were investigated. The effectiveness of the KWII and TCI to detect GEIs in a diverse range of simulated data sets and a Crohn disease data set was assessed. The sensitivity of the KWII and TCI spectra to biological and study-design variables was determined. Head-to-head comparisons with the relevance-chain, multifactor dimensionality reduction, and the pedigree disequilibrium test (PDT) methods were obtained. The KWII and TCI spectra, which are graphical summaries of the KWII and TCI for each subset of environmental and genotype variables, were found to detect each known GEI in the simulated data sets. The patterns in the KWII and TCI spectra were informative for factors such as case-control misassignment, locus heterogeneity, allele frequencies, and linkage disequilibrium. The KWII and TCI spectra were found to have excellent sensitivity for identifying the key disease-associated genetic variations in the Crohn disease data set. In head-to-head comparisons with the relevance-chain, multifactor dimensionality reduction, and PDT methods, the results from visual interpretation of the KWII and TCI spectra performed satisfactorily. The KWII and TCI are promising metrics for visualizing GEIs. They are capable of detecting interactions among numerous single-nucleotide polymorphisms and environmental variables for a diverse range of GEI models.

Chanda, Pritam; Zhang, Aidong; Brazeau, Daniel; Sucheston, Lara; Freudenheim, Jo L.; Ambrosone, Christine; Ramanathan, Murali

2007-01-01

45

Determining 252Cf source strength by absolute passive neutron correlation counting  

NASA Astrophysics Data System (ADS)

Physically small, lightly encapsulated, radionuclide sources containing 252Cf are widely used for a vast variety of industrial, medical, educational and research applications requiring a convenient source of neutrons. For many quantitative applications, such as detector efficiency calibrations, the absolute strength of the neutron emission is needed. In this work we show how, by using a neutron multiplicity counter the neutron emission rate can be obtained with high accuracy. This provides an independent and alternative way to create reference sources in-house for laboratories such as ours engaged in international safeguards metrology. The method makes use of the unique and well known properties of the 252Cf spontaneous fission system and applies advanced neutron correlation counting methods. We lay out the foundation of the method and demonstrate it experimentally. We show that accuracy comparable to the best methods currently used by national bodies to certify neutron source strengths is possible.

Croft, S.; Henzlova, D.

2013-06-01

46

Digital Array Gas Correlation Radiometry (DAGR): A New Approach to Passively Sensing the Planetary Boundary Layer  

NASA Astrophysics Data System (ADS)

A prototype sensor designed to measure atmospheric gas absorption using scattered solar light at SWIR wavelengths has been developed and tested in the lab. This sensor combines a novel use of modern digital detector arrays with gas filter correlation radiometry (GFCR). The combination overcomes tradition difficulties, involving spatially varying albedo, in the spectral analysis of nadir SWIR observations from moving platforms. GFCR provides exceptional spectral selectivity due to typical effective resolving power of 105 and normalized difference signals that are ideally insensitive to spectrally flat attenuators, such as aerosol. By de-focusing the two beams produced by the GFCR and using detector arrays to obtain beam intensity through simple pixel summation, the instrument achieves dual-beam GFCR observations that are exactly matched in time and space. This characteristic nearly eliminates sensitivity to the time and space variation of surface albedo. Plus, measuring beam intensity by summing detector pixel output provides almost unlimited dynamic range, considering the flexibility of integration times provided with modern detector arrays. This poster presents the instrument design and modeling results. Funded under the NASA Planetary Instrument Definition and Design Program, PIDD, the work has focused on evaluating a potential Mars methane measurement near 3.3 microns. Results evaluating gas spectral sensitivity, insensitivity to albedo, non-linearity effects, dynamic range, signal drift, dark current, background emission and other effects are presented. Application to other gases is briefly discussed.

Crowther, B.; Peterson, J.; Gordley, L. L.; Hervig, M. E.; Burton, J.; Fish, C. S.; Diskin, G. S.; Sachse, G. W.

2010-12-01

47

Understanding risk for psychopathology through imaging gene-environment interactions  

PubMed Central

Examining the interplay of genes, experience, and the brain is critical to understanding psychopathology. We review the recent gene-environment interaction (GxE) and imaging genetics literature with the goal of developing models to bridge these approaches within single imaging gene-environment interaction (IGxE) studies. We explore challenges inherent in both GxE and imaging genetics and highlight studies that address these limitations. In specifying IGxE models, we examine statistical methods for combining these approaches, and explore plausible biological mechanisms (e.g., epigenetics) through which these conditional mechanisms can be understood. Finally, we discuss the potential contribution that IGxE studies can make to understanding psychopathology and developing more personalized and effective prevention and treatment.

Hyde, Luke W.; Bogdan, Ryan; Hariri, Ahmad R.

2011-01-01

48

Eating disorders, gene–environment interactions and epigenetics  

Microsoft Academic Search

This review describes the various subtypes of eating disorders and examines factors associated with the risk of illness. It considers evidence that the development and maintenance of eating disorders is due to gene–environment interactions (GxE) that alter genetic expression via epigenetic processes. It describes how environmental factors such as those associated with nutrition and\\/or stress may cause epigenetic changes which

Iain C. Campbell; Jonathan Mill; Rudolf Uher; Ulrike Schmidt

2011-01-01

49

A flexible Bayesian model for studying gene-environment interaction.  

PubMed

An important follow-up step after genetic markers are found to be associated with a disease outcome is a more detailed analysis investigating how the implicated gene or chromosomal region and an established environment risk factor interact to influence the disease risk. The standard approach to this study of gene-environment interaction considers one genetic marker at a time and therefore could misrepresent and underestimate the genetic contribution to the joint effect when one or more functional loci, some of which might not be genotyped, exist in the region and interact with the environment risk factor in a complex way. We develop a more global approach based on a Bayesian model that uses a latent genetic profile variable to capture all of the genetic variation in the entire targeted region and allows the environment effect to vary across different genetic profile categories. We also propose a resampling-based test derived from the developed Bayesian model for the detection of gene-environment interaction. Using data collected in the Environment and Genetics in Lung Cancer Etiology (EAGLE) study, we apply the Bayesian model to evaluate the joint effect of smoking intensity and genetic variants in the 15q25.1 region, which contains a cluster of nicotinic acetylcholine receptor genes and has been shown to be associated with both lung cancer and smoking behavior. We find evidence for gene-environment interaction (P-value?=?0.016), with the smoking effect appearing to be stronger in subjects with a genetic profile associated with a higher lung cancer risk; the conventional test of gene-environment interaction based on the single-marker approach is far from significant. PMID:22291610

Yu, Kai; Wacholder, Sholom; Wheeler, William; Wang, Zhaoming; Caporaso, Neil; Landi, Maria Teresa; Liang, Faming

2012-01-26

50

Gene-environment interaction in posttraumatic stress disorder  

Microsoft Academic Search

The purpose of this article is to encourage research investigating the role of measured gene-environment interaction (G × E)\\u000a in the etiology of posttraumatic stress disorder (PTSD). PTSD is uniquely suited to the study of G × E as the diagnosis requires\\u000a exposure to a potentially-traumatic life event. PTSD is also moderately heritable; however, the role of genetic factors in\\u000a PTSD etiology has been

Karestan C. Koenen; Nicole R. Nugent; Ananda B. Amstadter

2008-01-01

51

A methodology to establish a database to study gene environment interactions for childhood asthma  

Microsoft Academic Search

BACKGROUND: Gene-environment interactions are likely to explain some of the heterogeneity in childhood asthma. Here, we describe the methodology and experiences in establishing a database for childhood asthma designed to study gene-environment interactions (PAGES - Paediatric Asthma Gene Environment Study). METHODS: Children with asthma and under the care of a respiratory paediatrician are being recruited from 15 hospitals between 2008

Stephen W Turner; Jon G Ayres; Tatiana V Macfarlane; Anil Mehta; Gita Mehta; Colin N Palmer; Steve Cunningham; Tim Adams; Krishnan Aniruddhan; Claire Bell; Donna Corrigan; Jason Cunningham; Andrew Duncan; Gerard Hunt; Richard Leece; Una MacFadyen; Jonathan McCormick; Sally McLeish; Andrew Mitra; Deborah Miller; Elizabeth Waxman; Alan Webb; Slawomir Wojcik; Somnath Mukhopadhyay; Donald Macgregor

2010-01-01

52

Confluence of Genes, Environment, Development, and Behavior in a Post-GWAS World  

PubMed Central

This article serves to outline a research paradigm to investigate main effects and interactions of genes, environment, and development on behavior and psychiatric illness. We provide a historical context for candidate gene studies and genome-wide association studies, including benefits, limitations, and expected payoff. Using substance use and abuse as our driving example, we then turn to the importance of etiological psychological theory in guiding genetic, environmental, and developmental research, as well as the utility of refined phenotypic measures, such as endophenotypes, in the pursuit of etiological understanding and focused tests of genetic and environmental associations. Phenotypic measurement has received considerable attention and is informed by psychometrics, while the environment remains relatively poorly measured and is often confounded with genetic effects (i.e., gene-environment correlation). Genetically-informed designs which—thanks to ever cheaper genotyping—are no longer are limited to twin and adoption studies, are required to understand environmental influences. Finally, we outline the vast amount of individual differences in structural genomic variation, most of which remains to be leveraged in genetic association tests. While the genetic data can be burdensomely massive (tens of millions of variants per person), we argue that improved understanding of genomic structure and function will provide investigators with new tools to test specific a priori hypotheses derived from etiological psychological theory, much like current candidate gene research, but with less confusion and more payoff than candidate gene research has to date.

Vrieze, Scott I.; Iacono, William G.; McGue, Matt

2012-01-01

53

A novel gene-environment interaction involved in endometriosis  

PubMed Central

Objective To establish a well-defined cohort for genetic epidemiology studies of endometriosis and conduct a pilot study to confirm validity using existing data associated with endometriosis. Methods Between January and May 2010, a nested cohort within a population-based biobank was established in Marshfield, Wisconsin, USA. The inclusion criteria were women who had laparoscopy or hysterectomy. Fifty-one pleiotropic genetic polymorphisms and other established risk factors, such as smoking status and body mass index, were compared between endometriosis cases and controls. Results From the existing biobank, 796 cases and 501 controls were identified, and 259 women with endometriosis were enrolled specifically for the nested cohort within this biobank. A single nucleotide polymorphism in the MMP1 gene significantly differed between cases and controls only when stratified by smoking status. Minor allele frequency was higher in control women who smoked than in women with endometriosis who smoked (55.5% versus 45.5%, ?2=8.2, P=0.017); the inverse relationship was found in non-smoker control women. Conclusions Women with endometriosis were successfully recruited to participate in a general biobank, and a novel gene–environment interaction was identified. The findings suggest that important potential genetic associations may be missed if gene–environment interactions with known epidemiologic risk factors are not considered.

McCarty, Catherine A.; Berg, Richard L.; Welter, Joseph D.; Kitchner, Terrie E.; Kemnitz, Joseph W.

2011-01-01

54

Gene-Environment Interaction and Children's Health and Development  

PubMed Central

Purpose of Review A systematic approach to studying gene-environment interaction can have immediate impact on our understanding of how environmental factors induce developmental disease and toxicity and provide biological insight for potential treatment and prevention measures. Recent Findings Because DNA sequence is static, genetic studies typically are not conducted prospectively. This limits the ability to incorporate environmental data into an analysis, as such data is usually collected cross-sectionally. Prospective environmental data collection could account for the role of critical windows of susceptibility that likely corresponds to the expression of specific genes and gene pathways. The use of large scale genomic platforms to discover genetic variants that modify environmental exposure in conjunction with a priori planned replication studies would reduce the number of false positive results. Summary Using a genome-wide approach, combined with a prospective longitudinal of environmental exposure at critical developmental windows is the optimal design for gene-environment interaction research. This approach would discover susceptibility variants, then validate the findings in an independent sample of children. Designs which combine the strengths and methodologies of each field will yield data which can account for both genetic variability and the role of critical developmental windows in the etiology of childhood disease and development.

Wright, Robert O.; Christiani, David

2010-01-01

55

Correlation between active and passive isometric force and intramuscular pressure in the isolated rabbit tibialis anterior muscle.  

PubMed

The purpose of this study was to quantify the relationship between intramuscular pressure (IMP) and muscle force during isometric muscle contraction of the rabbit tibialis anterior (TA) absent the effect of either bone or fascia. To quantify this relationship, length-tension experiments were performed on the isolated TA of the New Zealand White rabbit (mass=2.5+/-0.5kg, n=12). The knee was fixed in a custom jig, the distal tendon of the TA was attached to a servomotor, and a 360 microm fiber optic pressure transducer was inserted into the TA. The peroneal nerve was stimulated to define optimal length (L(0)). The length-tension curve was created using 40Hz isometric contractions with 2-min rest intervals between each contraction. Measurements began at L(0)-50%L(f) and progressed to L(0)+50%L(f), changing the length-tension in 5% L(f) increments after each contraction. Qualitatively, the length-tension curve for isometric contractions was mimicked by the length-pressure curve for both active and passive conditions. Linear regression was performed individually for each animal for the ascending and descending limb of the length-tension curve and for active and passive conditions. Pressure-force coefficients of determination ranged from 0.138-0.963 for the active ascending limb and 0.343-0.947 for the active descending limb. Passive pressure coefficients of determination ranged from 0.045-0.842 for the ascending limb and 0.672-0.982 for the descending limb. These data indicate that IMP measurement provide a fairly accurate index of relative muscle force, especially at muscle lengths longer than optimal. PMID:12600341

Davis, Jennifer; Kaufman, Kenton R; Lieber, Richard L

2003-04-01

56

Gene-environment Interaction in Posttraumatic Stress Disorder: An Update  

PubMed Central

This article provides a detailed review of the extant gene-environment interaction (GxE) research in the etiology of posttraumatic stress disorder (PTSD). We begin by a discussion of why PTSD is uniquely fitting for the innovative framework of GxE methodology, followed by a review of the heritability and main effect molecular genetics studies of PTSD. Next, we discuss the six GxE investigations to date on PTSD. We end with a discussion of future directions and significance of this research, with an emphasis on the expansion of psychosocial factors that may be fitting ‘E’ variables for inclusion in this new research area. We posit that GxE research is vital to elucidating risk and resilience following exposure to a potentially traumatic event.

Koenen, Karestan C.; Amstadter, Ananda B.; Nugent, Nicole R.

2009-01-01

57

Gene-environment interaction in posttraumatic stress disorder  

PubMed Central

The purpose of this article is to encourage research investigating the role of measured gene-environment interaction (G × E) in the etiology of posttraumatic stress disorder (PTSD). PTSD is uniquely suited to the study of G × E as the diagnosis requires exposure to a potentially-traumatic life event. PTSD is also moderately heritable; however, the role of genetic factors in PTSD etiology has been largely neglected both by trauma researchers and psychiatric geneticists. First, we summarize evidence for genetic influences on PTSD from family, twin, and molecular genetic studies. Second, we discuss the key challenges in G × E studies of PTSD and offer practical strategies for addressing these challenges and for discovering replicable G × E for PTSD. Finally, we propose some promising new directions for PTSD G × E research. We suggest that G × E research in PTSD is essential to understanding vulnerability and resilience following exposure to a traumatic event.

Nugent, Nicole R.; Amstadter, Ananda B.

2009-01-01

58

Risk, Resilience, and Gene-Environment Interplay in Primates  

PubMed Central

Objectives: The primary objectives of the body of research reported here was to demonstrate significant interactions between genetic and social environmental factors that clearly influenced both the biological and behavioral responses of rhesus monkeys to social stressors such as separation from familial and/or familiar conspecifics throughout development and to investigate possible mechanisms underlying such interactions. Methods: Prospective longitudinal studies of rhesus monkeys reared in both captive and naturalistic settings have examined individual differences in biological and behavioral responses to stress throughout the lifespan. Results: Approximately 20% of monkeys in both settings consistently display unusually fearful and anxious-like behavioral reactions to novel, mildly stressful social situations and depressive-like symptoms following repeated separations from familial and/or familiar conspecifics during their infant and juvenile years, as well as profound and prolonged activation of the hypothalamic-pituitary-adrenal (HPA) axis in both situations. Both genetic and experiential factors – as well as their interaction -- are implicated in these reactions to social stress. For example, a specific polymorphism in the serotonin transporter gene is associated with deficits in neonatal neurobehavioral functioning and in extreme behavioral and adreno-cortical responses to social separation among infant and juvenile monkeys who experienced insecure early attachments but not in monkeys who developed secure attachment relationships with their mothers during infancy (maternal “buffering”). Similar instances of maternal “buffering” have been demonstrated in significant gene-environment interplay involving several other “candidate” gene polymorphisms. Moreover, because the attachment style of a monkey mother is typically “copied” by her daughters when they become mothers themselves, similar “buffering” is likely to occur for the next generation of infants carrying so-called “risk” alleles. Conclusions: Specific gene-environment interactions can influence behavioral and biological reactions to social stress not only throughout development but also across successive generations of rhesus monkey families.

Suomi, Stephen J.

2011-01-01

59

Electrophysiological Correlates of the Threshold to Detection of Passive Motion: An Investigation in Professional Volleyball Athletes with and without Atrophy of the Infraspinatus Muscle  

PubMed Central

The goal of the present study is to compare the electrophysiological correlates of the threshold to detection of passive motion (TTDPM) among three groups: healthy individuals (control group), professional volleyball athletes with atrophy of the infraspinatus muscle on the dominant side, and athletes with no shoulder pathologies. More specifically, the study aims at assessing the effects of infraspinatus muscle atrophy on the cortical representation of the TTDPM. A proprioception testing device (PTD) was used to measure the TTDPM. The device passively moved the shoulder and participants were instructed to respond as soon as movement was detected (TTDPM) by pressing a button switch. Response latency was established as the delay between the stimulus (movement) and the response (button press). Electroencephalographic (EEG) and electromyographic (EMG) activities were recorded simultaneously. An analysis of variance (ANOVA) and subsequent post hoc tests indicated a significant difference in latency between the group of athletes without the atrophy when compared both to the group of athletes with the atrophy and to the control group. Furthermore, distinct patterns of cortical activity were observed in the three experimental groups. The results suggest that systematically trained motor abilities, as well as the atrophy of the infraspinatus muscle, change the cortical representation of the different stages of proprioceptive information processing and, ultimately, the cortical representation of the TTDPM.

Salles, Jose Inacio; Cossich, Victor Rodrigues Amaral; Amaral, Marcus Vinicius; Monteiro, Martim T.; Cagy, Mauricio; Motta, Geraldo; Velasques, Bruna; Piedade, Roberto; Ribeiro, Pedro

2013-01-01

60

Passive solar heating  

SciTech Connect

Buildings have been designed to use solar gains for winter heating for several millenia, but the quantitative basis for passive solar design has only been developed in the last decade. A simplified lumped-capacitance model is used to provide insight into the physics of passive building behavior. Three passive design methods are described: the Solar Load Ratio (SLR) method based on correlations to simulation results; the Gordon-Zarmi closed-form analytical model; and the unutilizability model of Monsen and Klein. Model predictions are compared with measured results; agreement is good if measured building characteristics are used. Numerous passive houses use less than 2 Btu/ft/sup 2/-DD for auxiliary heating and consensus is developing that modest levels of passive glazing combined with superinsulation techniques can provide the best feature of both approaches. 28 references, 6 figures, 6 tables.

Claridge, D.E.; Mowris, R.J.

1985-01-01

61

Passive solar heating  

NASA Astrophysics Data System (ADS)

Buildings have been designed to use solar gains for winter heating for several millenia, but the quantitative basis for passive solar design has only been developed in the last decade. A simplified lumped capacitance model is used to provide insight into the physics of passive building behavior. Three passive design methods are described: the Solar Load Ratio (SLR) method based on correlations to simulation results; the Gordon/Zarmi closed form analytical mode;; and the ``unutilizability'' model of Monsen and Klein. Model predictions are compared with measured results; agreement is good if measured building characteristics are used. Numerous passive houses use less than 2 Btu/ft2-DD for auxiliary heating and consensus is developing that modest levels of passive glazing combined with superinsulation techniques can provide the best feature of both approaches.

Claridge, David E.; Mowris, Robert J.

1985-11-01

62

MAOA genotype, social exclusion and aggression: an experimental test of a gene-environment interaction.  

PubMed

In 2002, Caspi and colleagues provided the first epidemiological evidence that genotype may moderate individuals' responses to environmental determinants. However, in a correlational study great care must be taken to ensure the proper estimation of the causal relationship. Here, a randomized experiment was performed to test the hypothesis that the MAOA gene promoter polymorphism (MAOA-LPR) interacts with environmental adversity in determining aggressive behavior using laboratory analogs of real-life conditions. A sample of 57 Caucasian male students of Catalan and Spanish origin was recruited at the University of Barcelona. Ostracism, or social exclusion, was induced as environmental adversity using the Cyberball software. Laboratory aggression was assessed with the Point Subtraction Aggression Paradigm (PSAP), which was used as an analog of antisocial behavior. We also measured aggressiveness by means of the reduced version of the Aggression Questionnaire. The MAOA-LPR polymorphism showed a significant effect on the number of aggressive responses in the PSAP (F(1,53) = 4.63, P = 0.03, partial ?(2) = 0.08), as well as social exclusion (F(1,53) = 8.03, P = 0.01, partial ?(2) = 0.13). Most notably, however, we found that the MAOA-LPR polymorphism interacts significantly with social exclusion in order to provoke aggressive behavior (F(1,53) = 4.42, P = 0.04, partial ?(2) = 0.08), remarkably, the low-activity allele of the MAOA-LPR polymorphism carriers in the ostracized group show significantly higher aggression scores than the rest. Our results support the notion that gene-environment interactions can be successfully reproduced within a laboratory using analogs and an appropriate design. We provide guidelines to test gene-environment interactions hypotheses under controlled, experimental settings. PMID:23067570

Gallardo-Pujol, D; Andrés-Pueyo, A; Maydeu-Olivares, A

2012-11-28

63

Passive Sonar  

NASA Astrophysics Data System (ADS)

Passive sonar is a method for detecting acoustic signals in an underwater environment, usually the ocean. The difference between passive and active sonar is that a passive sonar system emits no signals; instead, its purpose is to detect the acoustic signals emanating from external sources. From an historical perspective, the main impetus for the research and development of passive sonar has been its military applications, in particular, the acoustic detection of submarines.

Maranda, Brian H.

64

Gene-environment interaction and male reproductive function  

PubMed Central

As genetic factors can hardly explain the changes taking place during short time spans, environmental and lifestyle-related factors have been suggested as the causes of time-related deterioration of male reproductive function. However, considering the strong heterogeneity of male fecundity between and within populations, genetic variants might be important determinants of the individual susceptibility to the adverse effects of environment or lifestyle. Although the possible mechanisms of such interplay in relation to the reproductive system are largely unknown, some recent studies have indicated that specific genotypes may confer a larger risk of male reproductive disorders following certain exposures. This paper presents a critical review of animal and human evidence on how genes may modify environmental effects on male reproductive function. Some examples have been found that support this mechanism, but the number of studies is still limited. This type of interaction studies may improve our understanding of normal physiology and help us to identify the risk factors to male reproductive malfunction. We also shortly discuss other aspects of gene-environment interaction specifically associated with the issue of reproduction, namely environmental and lifestyle factors as the cause of sperm DNA damage. It remains to be investigated to what extent such genetic changes, by natural conception or through the use of assisted reproductive techniques, are transmitted to the next generation, thereby causing increased morbidity in the offspring.

Axelsson, Jonatan; Bonde, Jens Peter; Giwercman, Yvonne L.; Rylander, Lars; Giwercman, Aleksander

2010-01-01

65

BPD's interpersonal hypersensitivity phenotype: a gene-environment-developmental model.  

PubMed

This paper explores the development of BPD as it might emerge in the child's early interpersonal reactions and how such reactions might evolve into the interpersonal pattern that typifies BPD. It begins to bridge the relevant bodies of clinical literature on the borderline's prototypic interpersonal problems with the concurrently expanding relevant literature on early child development. We will start by considering how a psychobiological disposition to BPD is likely to include a constitutional diathesis for relational reactivity, that is, for hypersensitivity to interpersonal stressors. Data relevant to this disposition's manifestations in adult clinical samples and to its heritability and neurobiology will be reviewed. We then consider how such a psychobiological disposition for interpersonal reactivity might contribute to the development of a disorganized-ambivalent form of attachment, noting especially the likely contributions of both the predisposed child and of parents who are themselves predisposed to maladaptive responses, leading to an escalation of problematic transactions. Evidence concerning both the genetics and the developmental pathways associated with disorganized attachments will be considered. Emerging links between such developmental pathways and adult BPD will be described, in particular the potential appearance by early- to middle-childhood of controlling-caregiving or controlling-punitive interpersonal strategies. Some implications from this gene-environment interactional theory for a better developmental understanding of BPD's etiology are discussed. PMID:18312121

Gunderson, John G; Lyons-Ruth, Karlen

2008-02-01

66

Passive Radar.  

National Technical Information Service (NTIS)

The basic ideas and concepts of one of the newest branches of radar, that of passive radar, are discussed. A great deal of attention is devoted to questions of the use of passive radar by the armed forces. The physical fundamentals of passive radar, and t...

A. G. Nikolaev S. V. Pertsov

1975-01-01

67

Gene-Environment Interplay and Psychopathology: Multiple Varieties but Real Effects  

ERIC Educational Resources Information Center

|Gene-environment interplay is a general term that covers several divergent concepts with different meanings and different implications. In this review, we evaluate research evidence on four varieties of gene-environment interplay. First, we consider epigenetic mechanisms by which environmental influences alter the effects of genes. Second, we…

Rutter, Michael; Moffitt, Terrie E.; Caspi, Avshalom

2006-01-01

68

Editorial: gene-environment interplay in child psychology and psychiatry - challenges and ways forward.  

PubMed

This special issue in the Journal of Child Psychology and Psychiatry presents several invited articles examining gene-environment interplay in child development and psychopathology. Models of gene-environment interplay have been exhaustively discussed in the literature, including an important contribution by Rutter, Moffitt and Caspi (2006) published in this journal. PMID:24007414

Petrill, Stephen A; Bartlett, Christopher W; Blair, Clancy

2013-10-01

69

Can Clouds Dance? Neural Correlates of Passive Conceptual Expansion Using a Metaphor Processing Task: Implications for Creative Cognition  

ERIC Educational Resources Information Center

|Creativity has emerged in the focus of neurocognitive research in the past decade. However, a heterogeneous pattern of brain areas has been implicated as underpinning the neural correlates of creativity. One explanation for these divergent findings lies in the fact that creativity is not usually investigated in terms of its many underlying…

Rutter, Barbara; Kroger, Soren; Stark, Rudolf; Schweckendiek, Jan; Windmann, Sabine; Hermann, Christiane; Abraham, Anna

2012-01-01

70

A passive strain-energy function for elastic and muscular arteries: correlation of material parameters with histological data  

Microsoft Academic Search

A plethora of phenomenological and structure-motivated constitutive models have thus far been used as pseudoelastic descriptors\\u000a in arterial biomechanics, but their parameters have not been explicitly correlated with histology. This study associated biaxial\\u000a histological data with strain-energy function (SEF) parameters derived from uniaxial tension data of arteries from different\\u000a topographical sites (carotid artery vs. thoracic aorta vs. femoral artery). A

Dimitrios P. Sokolis

2010-01-01

71

Gene × environment interactions in the prediction of response to antidepressant treatment.  

PubMed

Major depressive disorder (MDD) is responsible for an increasing individual and global health burden. Extensive research on the genetic disposition to develop MDD and to predict the response to antidepressant treatment has yet failed to identify strong genetic effects. The concept of gene × environment interaction takes into account that environmental factors have been identified as important components in the development of MDD and combines both, genetic predisposition and environmental exposure, to elucidate complex traits such as MDD. Here, we review the current research on gene × environment interactions with regard to the development of MDD as well as response to antidepressant treatment. We hypothesize that gene × environment interactions delineate specific biological subtypes of depression and that individuals with such pathophysiological distinct types of depression will likely respond to different treatments. The elucidation of gene × environment interactions may thus not only help to understand the pathophysiology of MDD but could also provide markers for a personalized antidepressant therapy. PMID:23237009

Klengel, Torsten; Binder, Elisabeth B

2012-12-14

72

Passive Radar.  

National Technical Information Service (NTIS)

This book sets forth in brief the physical principles of passive radar, describes the functional diagrams and circuit peculiarities of the apparatus, and offers recommendations for modifying radar receivers to adapt them for receiving natural radio-freque...

A. G. Nikolaev S. V. Pertsov

1975-01-01

73

Passive euthanasia  

PubMed Central

The idea of passive euthanasia has recently been attacked in a particularly clear and explicit way by an "Ethics Task Force" established by the European Association of Palliative Care (EAPC) in February 2001. It claims that the expression "passive euthanasia" is a contradiction in terms and hence that there can be no such thing. This paper critically assesses the main arguments for the Task Force's view. Three arguments are considered. Firstly, an argument based on the (supposed) wrongness of euthanasia and the (supposed) permissibility of what is often called passive euthanasia. Secondly, the claim that passive euthanasia (so-called) cannot really be euthanasia because it does not cause death. And finally, a consequence based argument which appeals to the (alleged) bad consequences of accepting the category of passive euthanasia. We conclude that although healthcare professionals' nervousness about the concept of passive euthanasia is understandable, there is really no reason to abandon the category provided that it is properly and narrowly understand and provided that "euthanasia reasons" for withdrawing or withholding life-prolonging treatment are carefully distinguished from other reasons.

Garrard, E; Wilkinson, S

2005-01-01

74

In Vitro and In Vivo Characterization of Anthrax AntiProtective Antigen and Anti-Lethal Factor Monoclonal Antibodies after Passive Transfer in a Mouse Lethal Toxin Challenge Model To Define Correlates of Immunity  

Microsoft Academic Search

Passive transfer of antibody may be useful for preexposure prophylaxis against biological agents used as weapons of terror, such as Bacillus anthracis. Studies were performed to evaluate the ability of anthrax antiprotective antigen (anti-PA) and antilethal factor (anti-LF) neutralizing monoclonal antibodies (mAbs) to protect against an anthrax lethal toxin (LeTx) challenge in a mouse model and to identify correlates of

Herman F. Staats; S. Munir Alam; Richard M. Scearce; Shaun M. Kirwan; Julia Xianzhi Zhang; William M. Gwinn; Barton F. Haynes

2007-01-01

75

Genes, environments, and developmental research: methods for a multi-site study of early substance abuse.  

PubMed

The importance of including developmental and environmental measures in genetic studies of human pathology is widely acknowledged, but few empirical studies have been published. Barriers include the need for longitudinal studies that cover relevant developmental stages and for samples large enough to deal with the challenge of testing gene-environment-development interaction. A solution to some of these problems is to bring together existing data sets that have the necessary characteristics. As part of the National Institute on Drug Abuse-funded Gene-Environment-Development Initiative, our goal is to identify exactly which genes, which environments, and which developmental transitions together predict the development of drug use and misuse. Four data sets were used of which common characteristics include (1) general population samples, including males and females; (2) repeated measures across adolescence and young adulthood; (3) assessment of nicotine, alcohol, and cannabis use and addiction; (4) measures of family and environmental risk; and (5) consent for genotyping DNA from blood or saliva. After quality controls, 2,962 individuals provided over 15,000 total observations. In the first gene-environment analyses, of alcohol misuse and stressful life events, some significant gene-environment and gene-development effects were identified. We conclude that in some circumstances, already collected data sets can be combined for gene-environment and gene-development analyses. This greatly reduces the cost and time needed for this type of research. However, care must be taken to ensure careful matching across studies and variables. PMID:23461817

Costello, E Jane; Eaves, Lindon; Sullivan, Patrick; Kennedy, Martin; Conway, Kevin; Adkins, Daniel E; Angold, A; Clark, Shaunna L; Erkanli, Alaattin; McClay, Joseph L; Copeland, William; Maes, Hermine H; Liu, Youfang; Patkar, Ashwin A; Silberg, Judy; van den Oord, Edwin

2013-03-06

76

Correlation  

NSDL National Science Digital Library

The applets, created by Virginia Tech's Department of Statistics, allow you to see how different bivariate data look under different correlation structures. The "Movie" applet either creates data for a particular correlation or animates a multitude data sets ranging correlations from -1 to 1. The "Creation" applet allows the user to create a data set by adding or deleting points from the screen.

Anderson-Cook, C.; Robinson, T.; Dorai-Raj, S.

2009-09-14

77

Passive curvaton  

NASA Astrophysics Data System (ADS)

We propose a class of curvaton models which we call passive curvaton. In this Letter, two kinds of passive curvaton are considered. The first one is a pseudoscalar curvaton coupling to a gauge field. Different from the inflaton case, the constraint from formation of primordial black holes (PBHs) is much weaker and large non-Gaussianity (of the equiliteral type) can be produced. The second model is a dilaton-like scalar curvaton coupling to a gauge field. We investigate the scale dependence of non-Gaussianity in this model. In both models, the spectrum and non-Gaussianity are enhanced by the slow-roll parameter of the curvaton field. Other possible passive curvaton models are also mentioned.

Lin, Chia-Min

2013-07-01

78

Gene-Environment Interactions in Schizophrenia: Review of Epidemiological Findings and Future Directions  

PubMed Central

Concern is building about high rates of schizophrenia in large cities, and among immigrants, cannabis users, and traumatized individuals, some of which likely reflects the causal influence of environmental exposures. This, in combination with very slow progress in the area of molecular genetics, has generated interest in more complicated models of schizophrenia etiology that explicitly posit gene-environment interactions (EU-GEI. European Network of Schizophrenia Networks for the Study of Gene Environment Interactions. Schizophrenia aetiology: do gene-environment interactions hold the key? [published online ahead of print April 25, 2008] Schizophr Res; S0920-9964(08) 00170–9). Although findings of epidemiological gene-environment interaction (G × E) studies are suggestive of widespread gene-environment interactions in the etiology of schizophrenia, numerous challenges remain. For example, attempts to identify gene-environment interactions cannot be equated with molecular genetic studies with a few putative environmental variables “thrown in”: G × E is a multidisciplinary exercise involving epidemiology, psychology, psychiatry, neuroscience, neuroimaging, pharmacology, biostatistics, and genetics. Epidemiological G × E studies using indirect measures of genetic risk in genetically sensitive designs have the advantage that they are able to model the net, albeit nonspecific, genetic load. In studies using direct molecular measures of genetic variation, a hypothesis-driven approach postulating synergistic effects between genes and environment impacting on a final common pathway, such as “sensitization” of mesolimbic dopamine neurotransmission, while simplistic, may provide initial focus and protection against the numerous false-positive and false-negative results that these investigations engender. Experimental ecogenetic approaches with randomized assignment may help to overcome some of the limitations of observational studies and allow for the additional elucidation of underlying mechanisms using a combination of functional enviromics and functional genomics.

van Os, Jim; Rutten, Bart PF; Poulton, Richie

2008-01-01

79

Passive Seismic Imaging  

NASA Astrophysics Data System (ADS)

Traditionally, passive seismology connotes the use of earthquake signals from continuously recording receivers. Small time windows around the arrivals of earthquakes are then analyzed in myriad fashion. I will distinguish from this body of work, the notion of passive seismic imaging, which requires no knowledge of the time or characteristics of a source event. Instead, by using the ambient noise in the subsurface with all orders of scattering and thus randomized directionality, passive seismic imaging can produce results analogous to conventional controlled source experiments. Mathematical proof of the concept of passive seismic imaging has been presented in the literature from several foundations. The results reduce to the simple concept of cross-correlating many long recordings within a simultaneously deployed array. This generates panels with the kinematics of a shot-gather from a standard reflection seismic acquisition effort. Results from synthetic data sets show the validity of the method for point diffractor, and layered earth models. Noting the similarity of form of the standard approach to produce shot-gathers with the imaging condition of shot-profile migration, I then show that migrating the raw passive seismic data without the correlation step produces the the correct image. The synthetic data from above is used to demonstrate the technique. By comparison, this image is of better quality, and demands less compute time, than migrating the data having been cross-correlated first. Finally, both techniques are used to process a 2x2 meter, 72-channel array recorded on the beach sand of Monterey Bay, California. Approximately one meter below the sand, a six inch diameter plastic pipe was buried to serve as a target.

Artman, B. W.

2003-12-01

80

Genes, environment, and dyslexia. The 2005 Norman Geschwind Memorial Lecture.  

PubMed

This article presents an overview of some methods and results from our continuing studies of genetic and environmental influences on dyslexia, and on individual differences across the normal range that have been conducted over the past 25 years in the Colorado Learning Disabilities Research Center (CLDRC) and in related projects. CLDRC investigators compare the similarities of identical twin pairs who share all their genes and fraternal twins who share half their segregating genes to assess the balance of genetic, shared family environment, and nonshared environment influences on dyslexia and on individual differences across the normal range. We have learned that among the children we have studied in Colorado, group deficits in reading (dyslexia) and individual differences in reading across the normal range are primarily due to genetic influences, and these genetic influences are often shared with some of the same genetic influences on deficits and individual differences in language and ADHD. We have also learned from our molecular-genetic linkage studies that there are regions on several chromosomes likely to contain genes that influence dyslexia. Several specific genes within these regions have been tentatively identified through molecular-genetic association analyses, but much more research is needed to understand the pathways among specific genes, regions of noncoding DNA that regulate the activity of those genes, the brain, and dyslexia. I conclude with a discussion of our research on individual differences in early reading development, on the role of early learning constraints in dyslexia, and on how genetic influences are expressed through their interaction and correlation with the environment. PMID:17849199

Olson, Richard K

2006-12-01

81

Gene-environment interactions in 7610 women with breast cancer: prospective evidence from the Million Women Study  

PubMed Central

Summary Background Information is scarce about the combined effects on breast cancer incidence of low-penetrance genetic susceptibility polymorphisms and environmental factors (reproductive, behavioural, and anthropometric risk factors for breast cancer). To test for evidence of gene–environment interactions, we compared genotypic relative risks for breast cancer across the other risk factors in a large UK prospective study. Methods We tested gene–environment interactions in 7610 women who developed breast cancer and 10?196 controls without the disease, studying the effects of 12 polymorphisms (FGFR2-rs2981582, TNRC9-rs3803662, 2q35-rs13387042, MAP3K1-rs889312, 8q24-rs13281615, 2p-rs4666451, 5p12-rs981782, CASP8-rs1045485, LSP1-rs3817198, 5q-rs30099, TGFB1-rs1982073, and ATM-rs1800054) in relation to prospectively collected information about ten established environmental risk factors (age at menarche, parity, age at first birth, breastfeeding, menopausal status, age at menopause, use of hormone replacement therapy, body-mass index, height, and alcohol consumption). Findings After allowance for multiple testing none of the 120 comparisons yielded significant evidence of a gene–environment interaction. By contrast with previous suggestions, there was little evidence that the genotypic relative risks were affected by use of hormone replacement therapy, either overall or for oestrogen-receptor-positive disease. Only one of the 12 polymorphisms was correlated with any of the ten other risk factors: carriers of the high-risk C allele of MAP3K1-rs889312 were significantly shorter than non-carriers (mean height 162·4 cm [95% CI 162·1–162·7] vs 163·1 cm [162·9–163·2]; p=0·01 after allowance for multiple testing). Interpretation Risks of breast cancer associated with low-penetrance susceptibility polymorphisms do not vary significantly with these ten established environmental risk factors. Funding Cancer Research UK and the UK Medical Research Council.

Travis, Ruth C; Reeves, Gillian K; Green, Jane; Bull, Diana; Tipper, Sarah J; Baker, Krys; Beral, Valerie; Peto, Richard; Bell, John; Zelenika, Diana; Lathrop, Mark

2010-01-01

82

How Gene-Environment Interaction Affects Children's Anxious and Fearful Behavior. Science Briefs  

ERIC Educational Resources Information Center

|"Science Briefs" summarize the findings and implications of a recent study in basic science or clinical research. This brief reports on the study "Evidence for a Gene-Environment Interaction in Predicting Behavioral Inhibition in Middle Childhood" (N. A. Fox, K E. Nichols, H. A. Henderson, K. Rubin, L. Schmidt, D. Hamer, M. Ernst, and D. S.…

National Scientific Council on the Developing Child, 2007

2007-01-01

83

Gene × Environment Interactions in Reading Disability and Attention-Deficit\\/Hyperactivity Disorder  

Microsoft Academic Search

This article examines Gene × Environment (G × E) interactions in two comorbid developmental disorders—reading disability (RD) and attention-deficit\\/hyperactivity disorder (ADHD)—as a window on broader issues on G × E interactions in developmental psychology. The authors first briefly review types of G × E interactions, methods for detecting them, and challenges researchers confront in interpreting such interactions. They then review

Bruce F. Pennington; Lauren M. McGrath; Jenni Rosenberg; Holly Barnard; Shelley D. Smith; Erik G. Willcutt; Angela Friend; John C. DeFries; Richard K. Olson

2009-01-01

84

Commentary: Gene-Environment Interplay in the Context of Genetics, Epigenetics, and Gene Expression.  

ERIC Educational Resources Information Center

|Objective: To comment on the article in this issue of the Journal by Professor Michael Rutter, "Environmentally Mediated Risks for Psychopathology: Research Strategies and Findings," in the context of current research findings on gene-environment interaction, epigenetics, and gene expression. Method: Animal and human studies are reviewed that…

Kramer, Douglas A.

2005-01-01

85

Gender specific gene–environment interactions on laboratory-assessed aggression  

Microsoft Academic Search

We examined gene–environment interactive effects on aggressive behavior among men and women genotyped (short versus long alleles) for the serotonin transporter gene. Aggressive behavior was indexed via a laboratory paradigm that measured the intensity and duration of shocks delivered to a putative “employee”. Half of the participants were exposed to a physical stressor during the procedure (stress) and half were

Edelyn Verona; Thomas E. Joiner; Frank Johnson; Theodore W. Bender

2006-01-01

86

How Gene-Environment Interaction Affects Children's Anxious and Fearful Behavior. Science Briefs  

ERIC Educational Resources Information Center

"Science Briefs" summarize the findings and implications of a recent study in basic science or clinical research. This brief reports on the study "Evidence for a Gene-Environment Interaction in Predicting Behavioral Inhibition in Middle Childhood" (N. A. Fox, K E. Nichols, H. A. Henderson, K. Rubin, L. Schmidt, D. Hamer, M. Ernst, and D. S.…

National Scientific Council on the Developing Child, 2007

2007-01-01

87

From 'omics' to complex disease: a systems biology approach to gene-environment interactions in cancer  

Microsoft Academic Search

BACKGROUND: Cancer is a complex disease that involves a sequence of gene-environment interactions in a progressive process that cannot occur without dysfunction in multiple systems, including DNA repair, apoptotic and immune functions. Epigenetic mechanisms, responding to numerous internal and external cues in a dynamic ongoing exchange, play a key role in mediating environmental influences on gene expression and tumor development.

Sarah S. Knox

2010-01-01

88

A Platform for the Remote Conduct of Gene-Environment Interaction Studies  

PubMed Central

Background Gene-environment interaction studies offer the prospect of robust causal inference through both gene identification and instrumental variable approaches. As such they are a major and much needed development. However, conducting these studies using traditional methods, which require direct participant contact, is resource intensive. The ability to conduct gene-environment interaction studies remotely would reduce costs and increase capacity. Aim To develop a platform for the remote conduct of gene-environment interaction studies. Methods A random sample of 15,000 men and women aged 50+ years and living in Cardiff, South Wales, of whom 6,012 were estimated to have internet connectivity, were mailed inviting them to visit a web-site to join a study of successful ageing. Online consent was obtained for questionnaire completion, cognitive testing, re-contact, record linkage and genotyping. Cognitive testing was conducted using the Cardiff Cognitive Battery. Bio-sampling was randomised to blood spot, buccal cell or no request. Results A heterogeneous sample of 663 (4.5% of mailed sample and 11% of internet connected sample) men and women (47% female) aged 50–87 years (median?=?61 yrs) from diverse backgrounds (representing the full range of deprivation scores) was recruited. Bio-samples were donated by 70% of those agreeing to do so. Self report questionnaires and cognitive tests showed comparable distributions to those collected using face-to-face methods. Record linkage was achieved for 99.9% of participants. Conclusion This study has demonstrated that remote methods are suitable for the conduct of gene-environment interaction studies. Up-scaling these methods provides the opportunity to increase capacity for large-scale gene-environment interaction studies.

Gallacher, John; Collins, Rory; Elliott, Paul; Palmer, Stephen; Burton, Paul; Mitchell, Clive; John, Gareth; Lyons, Ronan

2013-01-01

89

Testing and estimating gene-environment interactions in family-based association studies.  

PubMed

We propose robust and efficient tests and estimators for gene-environment/gene-drug interactions in family-based association studies in which haplotypes, dichotomous/quantitative phenotypes, and complex exposure/treatment variables are analyzed. Using causal inference methodology, we show that the tests and estimators are robust against unmeasured confounding due to population admixture and stratification, provided that Mendel's law of segregation holds and that the considered exposure/treatment variable is not affected by the candidate gene under study. We illustrate the practical relevance of our approach by an application to a chronic obstructive pulmonary disease study. The data analysis suggests a gene-environment interaction between a single nucleotide polymorphism in the Serpine2 gene and smoking status/pack-years of smoking. Simulation studies show that the proposed methodology is sufficiently powered for realistic sample sizes and that it provides valid tests and effect size estimators in the presence of admixture and stratification. PMID:17970814

Vansteelandt, Stijn; Demeo, Dawn L; Lasky-Su, Jessica; Smoller, Jordan W; Murphy, Amy J; McQueen, Matt; Schneiter, Kady; Celedon, Juan C; Weiss, Scott T; Silverman, Edwin K; Lange, Christoph

2007-10-25

90

Gene-Environment Interaction in Adults’ IQ Scores: Measures of Past and Present Environment  

Microsoft Academic Search

Gene-environment interaction was studied in a sample of young (mean age 26 years, N = 385) and older (mean age 49 years, N = 370) adult males and females. Full scale IQ scores (FSIQ) were analyzed using biometric models in which additive genetic\\u000a (A), common environmental (C), and unique environmental (E) effects were allowed to depend on environmental measures. Moderators\\u000a under study were parental

Sophie van der Sluis; Gonneke Willemsen; Eco J. C. de Geus; Dorret I. Boomsma; Danielle Posthuma

2008-01-01

91

Improved Measures of Diet & Physical Activity for the Genes, Environment, & Health Initiative (GEI)  

Cancer.gov

The Genes, Environment, and Health Initiative (GEI) is a NIH-wide project led by the National Institute of Environmental Health Sciences (NIEHS) and the National Human Genome Research Institute (NHGRI). The overarching goal of the GEI is to determine the etiology of common diseases by focusing on the interaction of genetic and environmental factors to better understand how these interactions contribute to health and disease.

92

Gene-Environment Interaction Signatures by Quantitative mRNA Profiling in Exfoliated Buccal Mucosal Cells  

Microsoft Academic Search

Exfoliated cytologic specimens from mouth (buccal) epithelium may contain viable cells, permitting assay of gene expression for direct and noninvasive measurement of gene-environment interactions, such as for inhalation (e.g., tobacco smoke) exposures. We determined specific mRNA levels in exfoliated buccal cells collected by cytologic brush, using a recently developed RNA-specific real-time quantitative reverse transcrip- tion-PCR strategy. In a pilot study,

Simon D. Spivack; Gregory J. Hurteau; Ritu Jain; Shalini V. Kumar; Kenneth M. Aldous; John F. Gierthy; Laurence S. Kaminsky

2004-01-01

93

Parent–child pair design for detecting gene–environment interactions in complex diseases  

Microsoft Academic Search

It is becoming clear that the etiology of complex diseases involves not only genetic and environmental factors but also gene–environment\\u000a (GE) interactions. Therefore, it is important to take account of all these factors to improve the power of an epidemiological\\u000a study design. We propose here a novel parent–child pair (PCP) design for this purpose. In comparison with conventional designs,\\u000a this

Yuan-De Tan; Myriam Fornage; Varghese George; Hongyan Xu

2007-01-01

94

Gene-environment interaction tests for dichotomous traits in trios and sibships.  

PubMed

When testing for genetic effects, failure to account for a gene-environment interaction can mask the true association effects of a genetic marker with disease. Family-based association tests are popular because they are completely robust to population substructure and model misspecification. However, when testing for an interaction, failure to model the main genetic effect correctly can lead to spurious results. Here we propose a family-based test for interaction that is robust to model misspecification, but still sensitive to an interaction effect, and can handle continuous covariates and missing parents. We extend the FBAT-I gene-environment interaction test for dichotomous traits to using both trios and sibships. We then compare this extension to joint tests of gene and gene-environment interaction, and compare the joint test additionally to the main effects test of the gene. Lastly, we apply these three tests to a group of nuclear families ascertained according to affection with Bipolar Disorder. PMID:19365860

Hoffmann, Thomas J; Lange, Christoph; Vansteelandt, Stijn; Laird, Nan M

2009-12-01

95

Robust discovery of genetic associations incorporating gene-environment interaction and independence.  

PubMed

This article considers the detection and evaluation of genetic effects incorporating gene-environment interaction and independence. Whereas ordinary logistic regression cannot exploit the assumption of gene-environment independence, the proposed approach makes explicit use of the independence assumption to improve estimation efficiency. This method, which uses both cases and controls, fits a constrained retrospective regression in which the genetic variant plays the role of the response variable, and the disease indicator and the environmental exposure are the independent variables. The regression model constrains the association of the environmental exposure with the genetic variant among the controls to be null, thus explicitly encoding the gene-environment independence assumption, which yields substantial gain in accuracy in the evaluation of genetic effects. The proposed retrospective regression approach has several advantages. It is easy to implement with standard software, and it readily accounts for multiple environmental exposures of a polytomous or of a continuous nature, while easily incorporating extraneous covariates. Unlike the profile likelihood approach of Chatterjee and Carroll (Biometrika. 2005;92:399-418), the proposed method does not require a model for the association of a polytomous or continuous exposure with the disease outcome, and, therefore, it is agnostic to the functional form of such a model and completely robust to its possible misspecification. PMID:21228701

Tchetgen Tchetgen, Eric

2011-03-01

96

Combining Disease Models to Test for Gene-Environment Interaction in Nuclear Families  

PubMed Central

Summary It is useful to have robust gene-environment interaction tests that can utilize a variety of family structures in an efficient way. This paper focuses on tests for gene-environment interaction in the presence of main genetic and environmental effects. The objective is to develop powerful tests that can combine trio data with parental genotypes and discordant sibships when parents genotypes are missing. We first make a modest improvement on a method for discordant sibs (discordant on phenotype), but the approach does not allow one to use families when all offspring are affected, e.g. trios. We then make a modest improvement on a Mendelian transmission-based approach that is inefficient when discordant sibs are available, but can be applied to any nuclear family. Finally, we propose a hybrid approach that utilizes the most efficient method for a specific family type, then combines over families. We utilize this hybrid approach to analyze a chronic obstructive pulmonary disorder dataset to test for gene-environment interaction in the Serpine2 gene with smoking. The methods are freely available in the R package fbati.

Hoffmann, Thomas J.; Vansteelandt, Stijn; Lange, Christoph; Silverman, Edwin K.; DeMeo, Dawn L.; Laird, Nan M.

2011-01-01

97

Correlation  

NSDL National Science Digital Library

Three hypothetical rock sections along an East-West transect are provided. Students correlate the three sections using the biostratigraphy of planktic forams (as a proxy for age), benthic forams (as a proxy of depth), and lithology (as a proxy of environment). Students are asked to provide an interpretation of the history of this depositional basin. An ash bed of known age is added and students are asked to determine if this new information affects their interpretation. Finally, an interesting lithologic feature is added, and students are asked to provide a geological explanation.

Higgins, Pennilyn

98

Lumped Network Passivity Criteria.  

National Technical Information Service (NTIS)

The classical time-energy definition of passivity is employed to generate workable passivity criteria for lumped networks which are characterizable by standard form state equations. In general, the demonstration of passivity entails the construction of a ...

R. A. Rohrer

1967-01-01

99

A Pilot Study of Gene/Gene and Gene/Environment Interactions in Alzheimer Disease  

PubMed Central

Background: Although some genes associated with increased risk of Alzheimer Disease (AD) have been identified, few data exist related to gene/gene and gene/environment risk of AD. The purpose of this pilot study was to explore gene/gene and gene/environment associations in AD and to obtain data for sample size estimates for larger, more definitive studies of AD. Methods: The effect of gene/gene and gene/environment interaction related to late onset Alzheimer Disease (LOAD) was investigated in 153 subjects with LOAD and 302 gender matched controls enrolled in the Personalized Medicine Research Project, a population-based bio-repository. Genetic risk factors examined included APOE, ACE, OLR1,and CYP46 genes, and environmental factors included smoking, total cholesterol, LDL, HDL, triglycerides, C-reactive protein, blood pressure, statin use, and body mass index. Results: The mean age of the cases was 78.2 years and the mean age of the controls was 87.2 years. APOE4 was significantly associated with LOAD (OR=3.55, 95%CL=1.70, 7.45). Cases were significantly more likely to have ever smoked cigarettes during their life (49.3% versus 38.4%, p=0.03). The highest recorded blood pressure and pulse pressure measurements were significantly higher in the controls than the cases (all P<0.005). Although not statistically significant in this pilot study, the relationship of the following factors was associated in opposite directions with LOAD based on the presence of an APOE4 allele: obesity at the age of 50, ACE, OLR1, and CYP46. Conclusions: These pilot data suggest that gene/gene and gene/environment interactions may be important in LOAD, with APOE, a known risk factor for LOAD, affecting the relationship of ACE and OLR1 to LOAD. Replication with a larger sample size and in other racial/ethnic groups is warranted and the allele and risk factor frequencies will assist in choosing an appropriate sample size for a definitive study.

Ghebranious, Nader; Mukesh, Bickol; Giampietro, Philip F.; Glurich, Ingrid; Mickel, Susan F.; Waring, Stephen C.; McCarty, Catherine A.

2011-01-01

100

Environmental and gene-environment interactions and risk of rheumatoid arthritis.  

PubMed

Multiple environmental factors including hormones, dietary factors, infections, and exposure to tobacco smoke, as well as gene-environment interactions, have been associated with increased risk for rheumatoid arthritis (RA). The growing understanding of the prolonged period before the first onset of symptoms of RA suggests that these environmental and genetic factors are likely acting to drive the development of RA-related autoimmunity long before the appearance of the first joint symptoms and clinical findings that are characteristic of RA. This article reviews these factors and interactions, especially those that have been investigated in a prospective fashion before the symptomatic onset of RA. PMID:22819092

Karlson, Elizabeth W; Deane, Kevin

2012-05-30

101

Passive ocean acoustic tomography  

NASA Astrophysics Data System (ADS)

The possibility to apply natural acoustic ocean noise in the ocean and noise of distant vessels as sounding signals in order to determine the physical parameters of a water layer is considered in this paper. We developed the methods making it possible to suppress the non-diffuse components of noise produced, e.g., by local vessels and to account for hydrophone motion. These methods are applied to the noise records obtained in the course of a year-long experiment on long-range sound propagation in the Pacific Ocean. We confirmed experimentally our theoretical predictions as to the possibility of retrieving deterministic acoustic ray travel times in a nonuniform environment from a mutual correlation function of imperfectly diffuse (gradually anisotropic and spatially nonuniform) noise without invoking any data on its source. We performed passive measurements of sound velocity in the ocean with a relative error of about 0.1% by correlation of noise fields recorded with vertical aerials. This accuracy approaches that needed for oceanological applications. Further investigations are necessary to study the feasibility of passive acoustic tomography and thermometry in the ocean at distances of tens and hundreds of kilometers and the possibility to use simpler arrays not equipped with hydrophone positioning systems.

Godin, O. A.; Goncharov, V. V.; Zabotin, N. A.

2012-05-01

102

Passive solar technology  

SciTech Connect

The present status of passive solar technology is summarized, including passive solar heating, cooling and daylighting. The key roles of the passive solar system designer and of innovation in the building industry are described. After definitions of passive design and a summary of passive design principles are given, performance and costs of passive solar technology are discussed. Passive energy design concepts or methods are then considered in the context of the overall process by which building decisions are made to achieve the integration of new techniques into conventional design. (LEW).

Watson, D

1981-04-01

103

Maternal Stress during Pregnancy, ADHD Symptomatology in Children and Genotype: Gene-Environment Interaction  

PubMed Central

Objective Case control studies suggest a relationship between maternal stress during pregnancy and childhood ADHD. However, maternal smoking, parenting style and parental psychiatric disorder are possible confounding factors. Our objective was to control for these factors by using an intra-familial design, and investigate gene-environment interactions. Methods One hundred forty two children, ages 6 to 12, (71 with ADHD, and their 71 non-ADHD siblings) participated in the intra-familial study design. A larger sample of ADHD children (N=305) was genotyped for DAT1 and DRD4 to examine gene-environment interactions. Symptom severity was evaluated using the Child Behavior Checklist (CBCL) and the Conners’ Global Index for Parents (CGI-P). The Kinney Medical and Gynecological Questionnaire was used to report stressful events during pregnancies. Results Logistic regression indicated that mothers were more likely to have experienced high stress during pregnancy of their ADHD child compared to that of the unaffected sibling (OR: 6.3, p=.01). In the larger sample, DRD4 7/7 genotype was associated with increased symptom severity in the high stress pregnancy (p=.01). Conclusions Maternal stress during pregnancy was associated with the development of ADHD symptomatology after controlling for family history of ADHD and other environmental factors. This association could partly be mediated through the DRD4 genotype.

Grizenko, Natalie; Fortier, Marie-Eve; Zadorozny, Christin; Thakur, Geeta; Schmitz, Norbert; Duval, Renaud; Joober, Ridha

2012-01-01

104

Using Bayesian networks to discover relations between genes, environment, and disease  

PubMed Central

We review the applicability of Bayesian networks (BNs) for discovering relations between genes, environment, and disease. By translating probabilistic dependencies among variables into graphical models and vice versa, BNs provide a comprehensible and modular framework for representing complex systems. We first describe the Bayesian network approach and its applicability to understanding the genetic and environmental basis of disease. We then describe a variety of algorithms for learning the structure of a network from observational data. Because of their relevance to real-world applications, the topics of missing data and causal interpretation are emphasized. The BN approach is then exemplified through application to data from a population-based study of bladder cancer in New Hampshire, USA. For didactical purposes, we intentionally keep this example simple. When applied to complete data records, we find only minor differences in the performance and results of different algorithms. Subsequent incorporation of partial records through application of the EM algorithm gives us greater power to detect relations. Allowing for network structures that depart from a strict causal interpretation also enhances our ability to discover complex associations including gene-gene (epistasis) and gene-environment interactions. While BNs are already powerful tools for the genetic dissection of disease and generation of prognostic models, there remain some conceptual and computational challenges. These include the proper handling of continuous variables and unmeasured factors, the explicit incorporation of prior knowledge, and the evaluation and communication of the robustness of substantive conclusions to alternative assumptions and data manifestations.

2013-01-01

105

Combinatory approaches prevent preterm birth profoundly exacerbated by gene-environment interactions  

PubMed Central

There are currently more than 15 million preterm births each year. We propose that gene-environment interaction is a major contributor to preterm birth. To address this experimentally, we generated a mouse model with uterine deletion of Trp53, which exhibits approximately 50% incidence of spontaneous preterm birth due to premature decidual senescence with increased mTORC1 activity and COX2 signaling. Here we provide evidence that this predisposition provoked preterm birth in 100% of females exposed to a mild inflammatory insult with LPS, revealing the high significance of gene-environment interactions in preterm birth. More intriguingly, preterm birth was rescued in LPS-treated Trp53-deficient mice when they were treated with a combination of rapamycin (mTORC1 inhibitor) and progesterone (P4), without adverse effects on maternal or fetal health. These results provide evidence for the cooperative contributions of two sites of action (decidua and ovary) toward preterm birth. Moreover, a similar signature of decidual senescence with increased mTORC1 and COX2 signaling was observed in women undergoing preterm birth. Collectively, our findings show that superimposition of inflammation on genetic predisposition results in high incidence of preterm birth and suggest that combined treatment with low doses of rapamycin and P4 may help reduce the incidence of preterm birth in high-risk women.

Cha, Jeeyeon; Bartos, Amanda; Egashira, Mahiro; Haraguchi, Hirofumi; Saito-Fujita, Tomoko; Leishman, Emma; Bradshaw, Heather; Dey, Sudhansu K.; Hirota, Yasushi

2013-01-01

106

Using Bayesian networks to discover relations between genes, environment, and disease.  

PubMed

We review the applicability of Bayesian networks (BNs) for discovering relations between genes, environment, and disease. By translating probabilistic dependencies among variables into graphical models and vice versa, BNs provide a comprehensible and modular framework for representing complex systems. We first describe the Bayesian network approach and its applicability to understanding the genetic and environmental basis of disease. We then describe a variety of algorithms for learning the structure of a network from observational data. Because of their relevance to real-world applications, the topics of missing data and causal interpretation are emphasized. The BN approach is then exemplified through application to data from a population-based study of bladder cancer in New Hampshire, USA. For didactical purposes, we intentionally keep this example simple. When applied to complete data records, we find only minor differences in the performance and results of different algorithms. Subsequent incorporation of partial records through application of the EM algorithm gives us greater power to detect relations. Allowing for network structures that depart from a strict causal interpretation also enhances our ability to discover complex associations including gene-gene (epistasis) and gene-environment interactions. While BNs are already powerful tools for the genetic dissection of disease and generation of prognostic models, there remain some conceptual and computational challenges. These include the proper handling of continuous variables and unmeasured factors, the explicit incorporation of prior knowledge, and the evaluation and communication of the robustness of substantive conclusions to alternative assumptions and data manifestations. PMID:23514120

Su, Chengwei; Andrew, Angeline; Karagas, Margaret R; Borsuk, Mark E

2013-03-21

107

Natural and Orthogonal Interaction framework for modeling gene-environment interactions with application to lung cancer  

PubMed Central

Objectives We aimed at extending the natural and orthogonal interaction (NOIA) framework, developed for modeling gene-gene interactions in the analysis of quantitative traits, to allow for reduced genetic models, dichotomous traits, and gene-environment interactions. We evaluate the performance of the NOIA statistical models using simulated data and lung cancer data. Methods The NOIA statistical models are developed for the additive, dominant, recessive genetic models, and a binary environmental exposure. Using the Kronecker product rule, a NOIA statistical model is built to model gene-environment interactions. By treating the genotypic values as the logarithm of odds, the NOIA statistical models are extended to the analysis of case-control data. Results Our simulations showed that power for testing associations while allowing for interaction using the statistical model is much higher than using functional models for most of the scenarios we simulated. When applied to the lung cancer data, much smaller P-values were obtained using the NOIA statistical model for either the main effects or the SNP-smoking interactions for some of the SNPs tested. Conclusion The NOIA statistical models are usually more powerful than the functional models in detecting main effects and interaction effects for both quantitative traits and binary traits.

Ma, Jianzhong; Xiao, Feifei; Xiong, Momiao; Andrew, Angeline S; Brenner, Hermann; Duell, Eric J.; Haugen, Aage; Hoggart, Clive; Hung, Rayjean J.; Lazarus, Philip; Liu, Changlu; Matsuo, Keitaro; Mayordomo, Jose Ignacio; Schwartz, Ann G.; Staratschek-Jox, Andrea; Wichmann, Erich; Yang, Ping; Amos, Christopher I.

2012-01-01

108

Meconium Nicotine and Metabolites by Liquid Chromatography-Tandem Mass Spectrometry: Differentiation of Passive and Nonexposure and Correlation with Neonatal Outcome Measures  

Microsoft Academic Search

BACKGROUND: Meconium analysis is a diagnostically sensitive and objective alternative to maternal self- report for detecting prenatal tobacco exposure. Nico- tine and metabolite disposition in meconium is poorly characterized, and correlation of analytes' concen- trations with neonatal outcomes is unexplored. Our objectivesweretoquantifynicotine,cotinine,trans-3- hydroxycotinine (OH-cotinine), nornicotine, norcoti- nine, and glucuronide concentrations in meconium, identify the best biomarkers of in utero tobacco

Teresa R. Gray; Raquel Magri; Diaa M. Shakleya; Marilyn A. Huestis

109

Passive Acoustic Vessel Localization  

NASA Astrophysics Data System (ADS)

This thesis investigates the development of a low-cost passive acoustic system for localizing moving vessels to monitor areas where human activities such as fishing, snorkeling and poaching are restricted. The system uses several off-the-shelf sensors with unsynchronized clocks where the Time Difference of Arrival (TDOA) or time delay is extracted by cross-correlation of the signal between paired sensors. The cross-correlation function uses phase correlation or Phase Transform (PHAT) which whitens the cross-spectrum in order to de-emphasize dominant frequency components. Using the locations of pairs of sensors as foci, hyperbolic equations can be defined using the time delay between them. With three or more sensors, multiple hyperbolic functions can be calculated which intersect at a unique point: the boat's location. It is also found that increasing separation distances between sensors decreased the correlation between the signals. However larger separation distances have better localization capability than with small distances. Experimental results from the Columbia and Willamette Rivers are presented to demonstrate performance.

Suwal, Pasang Sherpa

110

Environmental and gene-environment interactions and risk of rheumatoid arthritis  

PubMed Central

Multiple environmental factors including hormones, dietary factors, infections and exposure to tobacco smoke as well as gene-environment interactions have been associated with increased risk for rheumatoid arthritis (RA). Importantly, the growing understanding of the prolonged period prior to the first onset of symptoms of RA suggests that these environmental and genetic factors are likely acting to drive the development of RA-related autoimmunity long before the appearance of the first joint symptoms and clinical findings that are characteristic of RA. Herein we will review these factors and interactions, especially those that have been investigated in a prospective fashion prior to the symptomatic onset of RA. We will also discuss how these factors may be explored in future study to further the understanding of the pathogenesis of RA, and ultimately perhaps develop preventive measures for this disease.

Karlson, Elizabeth W.; Deane, Kevin

2012-01-01

111

An attachment perspective on borderline personality disorder: advances in gene-environment considerations.  

PubMed

Accumulating evidence points to severe relationship dysfunction as the core epigenetic expression of borderline personality disorder (BPD). In adulthood, BPD is typified by disorganization within and across interpersonal domains of functioning. When interacting with their infants, mothers with BPD show marked withdrawal and frightening or frightened behavior, leading to disorganized infant-mother attachments. Linked to both infant disorganization and BPD is a maternal state of mind typified by unresolved mourning regarding past loss or trauma. Early risk factors for BPD in adulthood include maternal withdrawal in infancy and separation of 1 month or more from mother in the first 5 years of life. Likely contributing biological factors include genes linked to dopamine, serotonin, the hypothalamic-pituitary-adrenal axis, and neuropeptides. The complex gene-environment picture emerging confers risk or protection against BPD pathology in ways consistent with infants varying biological sensitivity to context. This line of research may refine early risk assessment and preventive mental health services. PMID:20425312

Steele, Howard; Siever, Larry

2010-02-01

112

Defining the environment in gene-environment research: lessons from social epidemiology.  

PubMed

In this article, we make the case that social epidemiology provides a useful framework to define the environment within gene-environment (G×E) research. We describe the environment in a multilevel, multidomain, longitudinal framework that accounts for upstream processes influencing health outcomes. We then illustrate the utility of this approach by describing how intermediate levels of social organization, such as neighborhoods or schools, are key environmental components of G×E research. We discuss different models of G×E research and encourage public health researchers to consider the value of including genetic information from their study participants. We also encourage researchers interested in G×E interplay to consider the merits of the social epidemiology model when defining the environment. PMID:23927514

Boardman, Jason D; Daw, Jonathan; Freese, Jeremy

2013-08-08

113

Gene-Environment Interaction in the Etiology of Mathematical Ability Using SNP Sets  

PubMed Central

Mathematics ability and disability is as heritable as other cognitive abilities and disabilities, however its genetic etiology has received relatively little attention. In our recent genome-wide association study of mathematical ability in 10-year-old children, 10 SNP associations were nominated from scans of pooled DNA and validated in an individually genotyped sample. In this paper, we use a ‘SNP set’ composite of these 10 SNPs to investigate gene-environment (GE) interaction, examining whether the association between the 10-SNP set and mathematical ability differs as a function of ten environmental measures in the home and school in a sample of 1888 children with complete data. We found two significant GE interactions for environmental measures in the home and the school both in the direction of the diathesis-stress type of GE interaction: The 10-SNP set was more strongly associated with mathematical ability in chaotic homes and when parents are negative.

Kovas, Yulia; Plomin, Robert

2010-01-01

114

Permutation and parametric bootstrap tests for gene--gene and gene--environment interactions  

PubMed Central

Summary Permutation tests are widely used in genomic research as a straightforward way to obtain reliable statistical inference without making strong distributional assumptions. However, in this paper we show that in genetic association studies it is not typically possible to construct exact permutation tests of gene-gene or gene-environment interaction hypotheses. We describe an alternative to the permutation approach in testing for interaction, a parametric bootstrap approach. Using simulations, we compare the finite-sample properties of a few often-used permutation tests and the parametric bootstrap. We consider interactions of an exposure with single and multiple polymorphisms. Finally, we address when permutation tests of interaction will be approximately valid in large samples for specific test statistics.

Buzkova, Petra; Lumley, Thomas; Rice, Kenneth

2010-01-01

115

Genome-wide gene-environment interaction analysis for asbestos exposure in lung cancer susceptibility  

PubMed Central

Asbestos exposure is a known risk factor for lung cancer. Although recent genome-wide association studies (GWASs) have identified some novel loci for lung cancer risk, few addressed genome-wide gene–environment interactions. To determine gene–asbestos interactions in lung cancer risk, we conducted genome-wide gene–environment interaction analyses at levels of single nucleotide polymorphisms (SNPs), genes and pathways, using our published Texas lung cancer GWAS dataset. This dataset included 317 498 SNPs from 1154 lung cancer cases and 1137 cancer-free controls. The initial SNP-level P-values for interactions between genetic variants and self-reported asbestos exposure were estimated by unconditional logistic regression models with adjustment for age, sex, smoking status and pack-years. The P-value for the most significant SNP rs13383928 was 2.17×10–6, which did not reach the genome-wide statistical significance. Using a versatile gene-based test approach, we found that the top significant gene was C7orf54, located on 7q32.1 (P = 8.90×10–5). Interestingly, most of the other significant genes were located on 11q13. When we used an improved gene-set-enrichment analysis approach, we found that the Fas signaling pathway and the antigen processing and presentation pathway were most significant (nominal P < 0.001; false discovery rate < 0.05) among 250 pathways containing 17 572 genes. We believe that our analysis is a pilot study that first describes the gene–asbestos interaction in lung cancer risk at levels of SNPs, genes and pathways. Our findings suggest that immune function regulation-related pathways may be mechanistically involved in asbestos-associated lung cancer risk. Abbreviations:CIconfidence intervalEenvironmentFDRfalse discovery rateGgeneGSEAgene-set-enrichment analysisGWASgenome-wide association studiesi-GSEAimproved gene-set-enrichment analysis approachORodds ratioSNPsingle nucleotide polymorphism

Wei, Qingyi Wei

2012-01-01

116

Gene-environment interactions in cancer epidemiology: a national cancer institute think tank report.  

PubMed

Cancer risk is determined by a complex interplay of genetic and environmental factors. Genome-wide association studies (GWAS) have identified hundreds of common (minor allele frequency [MAF] > 0.05) and less common (0.01 < MAF < 0.05) genetic variants associated with cancer. The marginal effects of most of these variants have been small (odds ratios: 1.1-1.4). There remain unanswered questions on how best to incorporate the joint effects of genes and environment, including gene-environment (G × E) interactions, into epidemiologic studies of cancer. To help address these questions, and to better inform research priorities and allocation of resources, the National Cancer Institute sponsored a "Gene-Environment Think Tank" on January 10-11, 2012. The objective of the Think Tank was to facilitate discussions on (1) the state of the science, (2) the goals of G × E interaction studies in cancer epidemiology, and (3) opportunities for developing novel study designs and analysis tools. This report summarizes the Think Tank discussion, with a focus on contemporary approaches to the analysis of G × E interactions. Selecting the appropriate methods requires first identifying the relevant scientific question and rationale, with an important distinction made between analyses aiming to characterize the joint effects of putative or established genetic and environmental factors and analyses aiming to discover novel risk factors or novel interaction effects. Other discussion items include measurement error, statistical power, significance, and replication. Additional designs, exposure assessments, and analytical approaches need to be considered as we move from the current small number of success stories to a fuller understanding of the interplay of genetic and environmental factors. PMID:24123198

Hutter, Carolyn M; Mechanic, Leah E; Chatterjee, Nilanjan; Kraft, Peter; Gillanders, Elizabeth M

2013-10-05

117

Adaptive passive fathometer processing.  

PubMed

Recently, a technique has been developed to image seabed layers using the ocean ambient noise field as the sound source. This so called passive fathometer technique exploits the naturally occurring acoustic sounds generated on the sea-surface, primarily from breaking waves. The method is based on the cross-correlation of noise from the ocean surface with its echo from the seabed, which recovers travel times to significant seabed reflectors. To limit averaging time and make this practical, beamforming is used with a vertical array of hydrophones to reduce interference from horizontally propagating noise. The initial development used conventional beamforming, but significant improvements have been realized using adaptive techniques. In this paper, adaptive methods for this process are described and applied to several data sets to demonstrate improvements possible as compared to conventional processing. PMID:20370000

Siderius, Martin; Song, Heechun; Gerstoft, Peter; Hodgkiss, William S; Hursky, Paul; Harrison, Chris

2010-04-01

118

Inhomogeneous anisotropic passive scalars  

NASA Astrophysics Data System (ADS)

We investigate the behaviour of the two-point correlation function in the context of passive scalars for non-homogeneous, non-isotropic forcing ensembles. Exact analytical computations can be carried out in the framework of the Kraichnan model for each anisotropic sector. We will focus our attention on the isotropic sector with isotropic forcing in order to obtain a description of the influence of purely inhomogeneous contributions. It is shown how the homogeneous solution is recovered at separations smaller than an intrinsic typical lengthscale induced by inhomogeneities, and how the different Fourier modes in the centre-of-mass variable recombine themselves to give a ‘beating’ (superposition of power laws) described by Bessel functions. The pure power-law behaviour is restored even if the inhomogeneous excitation takes place at very small scales.

Martins Afonso, M.; Sbragaglia, M.

119

Passive Building Control System.  

National Technical Information Service (NTIS)

The design is called Passive Building Predictive Control System. It consists of one central controller and a set of local understations, one in each working space (office room). It can manage passive solar gain, natural ventilation, heating and lighting i...

S. H. Liem P. J. Lute A. H. C. van Paassen M. Verwaal

1989-01-01

120

Passively Transmitted gp41 Antibodies in Babies Born from HIV-1 Subtype C-Seropositive Women: Correlation between Fine Specificity and Protection  

PubMed Central

HIV-exposed, uninfected (EUN) babies born to HIV-infected mothers are examples of natural resistance to HIV infection. In this study, we evaluated the titer and neutralizing potential of gp41-specific maternal antibodies and their correlation with HIV transmission in HIV-infected mother-child pairs. Specific gp41-binding and -neutralizing antibodies were determined in a cohort of 74 first-time mother-child pairs, of whom 40 mothers were infected with HIV subtype C. Within the infected mother cohort, 16 babies were born infected and 24 were PCR negative and uninfected at birth (i.e., exposed but uninfected). Thirty-four HIV-uninfected and HIV-unexposed mother-child pairs were included as controls. All HIV-positive mothers and their newborns showed high IgG titers to linear epitopes within the HR1 region and to the membrane-proximal (MPER) domain of gp41; most sera also recognized the disulfide loop immunodominant epitope (IDE). Antibody titers to the gp41 epitopes were significantly lower in nontransmitting mothers (P < 0.01) and in the EUN babies (P < 0.005) than in HIV-positive mother-child pairs. Three domains of gp41, HR1, IDE, and MPER, elicited antibodies that were effectively transmitted to EUN babies. Moreover, in EUN babies, epitopes overlapping the 2F5 epitope (ELDKWAS), but not the 4E10 epitope, were neutralization targets in two out of four viruses tested. Our findings highlight important epitopes in gp41 that appear to be associated with exposure without infection and would be important to consider for vaccine design.

Diomede, L.; Nyoka, S.; Pastori, C.; Scotti, L.; Zambon, A.; Sherman, G.; Gray, C. M.; Sarzotti-Kelsoe, M.

2012-01-01

121

Passively transmitted gp41 antibodies in babies born from HIV-1 subtype C-seropositive women: correlation between fine specificity and protection.  

PubMed

HIV-exposed, uninfected (EUN) babies born to HIV-infected mothers are examples of natural resistance to HIV infection. In this study, we evaluated the titer and neutralizing potential of gp41-specific maternal antibodies and their correlation with HIV transmission in HIV-infected mother-child pairs. Specific gp41-binding and -neutralizing antibodies were determined in a cohort of 74 first-time mother-child pairs, of whom 40 mothers were infected with HIV subtype C. Within the infected mother cohort, 16 babies were born infected and 24 were PCR negative and uninfected at birth (i.e., exposed but uninfected). Thirty-four HIV-uninfected and HIV-unexposed mother-child pairs were included as controls. All HIV-positive mothers and their newborns showed high IgG titers to linear epitopes within the HR1 region and to the membrane-proximal (MPER) domain of gp41; most sera also recognized the disulfide loop immunodominant epitope (IDE). Antibody titers to the gp41 epitopes were significantly lower in nontransmitting mothers (P < 0.01) and in the EUN babies (P < 0.005) than in HIV-positive mother-child pairs. Three domains of gp41, HR1, IDE, and MPER, elicited antibodies that were effectively transmitted to EUN babies. Moreover, in EUN babies, epitopes overlapping the 2F5 epitope (ELDKWAS), but not the 4E10 epitope, were neutralization targets in two out of four viruses tested. Our findings highlight important epitopes in gp41 that appear to be associated with exposure without infection and would be important to consider for vaccine design. PMID:22301151

Diomede, L; Nyoka, S; Pastori, C; Scotti, L; Zambon, A; Sherman, G; Gray, C M; Sarzotti-Kelsoe, M; Lopalco, L

2012-02-01

122

[Fundamental studies of passivity and passivity breakdown  

SciTech Connect

We developed and experimentally tested physical models for growth and breakdown of passive films on metal surfaces. These models are ``point defect models,`` in which the growth and breakdown are described in terms of movement of anion and cation vacancies. The work during the past 5 years resulted in: theory of growth and breakdown of passive films, theory of corrosion-resistant alloys, electronic structure of passive films, and estimation of damage functions for energy systems. Proposals are give for the five ongoing tasks. 10 figs.

Macdonald, D.D.

1993-07-01

123

Research Review: Gene-Environment Interaction Research in Youth Depression--A Systematic Review with Recommendations for Future Research  

ERIC Educational Resources Information Center

Background: Depression is a major public health problem among youth, currently estimated to affect as many as 9% of US children and adolescents. The recognition that both genes (nature) and environments (nurture) are important for understanding the etiology of depression has led to a rapid growth in research exploring gene-environment interactions…

Dunn, Erin C.; Uddin, Monica; Subramanian, S. V.; Smoller, Jordan W.; Galea, Sandro; Koenen, Karestan C.

2011-01-01

124

Research Review: Gene-Environment Interaction Research in Youth Depression--A Systematic Review with Recommendations for Future Research  

ERIC Educational Resources Information Center

|Background: Depression is a major public health problem among youth, currently estimated to affect as many as 9% of US children and adolescents. The recognition that both genes (nature) and environments (nurture) are important for understanding the etiology of depression has led to a rapid growth in research exploring gene-environment

Dunn, Erin C.; Uddin, Monica; Subramanian, S. V.; Smoller, Jordan W.; Galea, Sandro; Koenen, Karestan C.

2011-01-01

125

Gene-Environment Interactions across Development: Exploring DRD2 Genotype and Prenatal Smoking Effects on Self-Regulation  

ERIC Educational Resources Information Center

|Genetic factors dynamically interact with both pre- and postnatal environmental influences to shape development. Considerable attention has been devoted to gene-environment interactions (G x E) on important outcomes (A. Caspi & T. E. Moffitt, 2006). It is also important to consider the possibility that these G x E effects may vary across…

Wiebe, Sandra A.; Espy, Kimberly Andrews; Stopp, Christian; Respass, Jennifer; Stewart, Peter; Jameson, Travis R.; Gilbert, David G.; Huggenvik, Jodi I.

2009-01-01

126

Methodology of laboratory measurements in prospective studies on gene–environment interactions: The experience of GenAir  

Microsoft Academic Search

Several large prospective investigations are under way or are planned in different parts of the world, aiming at the investigation of gene–environment interactions for chronic diseases. Technical, practical and ethical issues are raised by such large investigations. Here we describe how such issues were approached within a case–control study nested in EPIC, a large European cohort, and the kind of

M. Peluso; P. Hainaut; L. Airoldi; H. Autrup; A. Dunning; S. Garte; E. Gormally; C. Malaveille; G. Matullo; A. Munnia; E. Riboli; P. Vineis

2005-01-01

127

Normal and abnormal cerebrovascular development: gene-environment interactions during early life with later life consequences.  

PubMed

A greater understanding of cerebrovascular health and disease requires the consideration of recent neuroscience advances concerning neuroplasticity in the context of classical developmental neurology principles. Consideration of the ontogenetic interplay of nature and nurture influencing brain development during prenatal and early postnatal time periods should consider the concept of the developmental origins of neurological health and disease. Adaptive and maladaptive effects of neuroplasticity require a systems biology approach integrating molecular, receptor, cellular, neural network, and behavioral perspectives, culminating in the structural and functional cerebrovascular phenotypes that express health or disease across the lifespan. Cognizance of the interrelationships among maternal, placental, fetal, and neonatal factors requires an interdisciplinary appreciation of genetic/epigenetic forces of neuroplasticity during early life that incrementally influence cerebrovascular health or disease throughout childhood and adulthood. Knowledge of the systemic effects of multiorgan function on cerebrovascular development further broadens the systems biology approach to general plasticity of the individual as a whole organism. Short- and long-term consequences of the positive and negative effects of neuroplasticity must consider ongoing gene-environment interactions with maturation and aging, superimposed on earlier fetal/neonatal experiences that sustain neurological health or contribute to disease during childhood and adulthood. PMID:23622309

Scher, Mark S

2013-01-01

128

Genes, Environments, Personality, and Successful Aging: Toward a Comprehensive Developmental Model in Later Life  

PubMed Central

Background. Outcomes in aging and health research, such as longevity, can be conceptualized as reflecting both genetic and environmental (nongenetic) effects. Parsing genetic and environmental influences can be challenging, particularly when taking a life span perspective, but an understanding of how genetic variants and environments relate to successful aging is critical to public health and intervention efforts. Methods. We review the literature, and survey promising methods, to understand this interplay. We also propose the investigation of personality as a nexus connecting genetics, environments, and health outcomes. Results. Personality traits may reflect psychological mechanisms by which underlying etiologic (genetic and environmental) effects predispose individuals to broad propensities to engage in (un)healthy patterns of behavior across the life span. In terms of methodology, traditional behavior genetic approaches have been used profitably to understand how genetic factors and environments relate to health and personality in somewhat separate literatures; we discuss how other behavior genetic approaches can help connect these literatures and provide new insights. Conclusions. Co-twin control designs can be employed to help determine causality via a closer approximation of the idealized counterfactual design. Gene-by-environment interaction (G × E) designs can be employed to understand how individual difference characteristics, such as personality, might moderate genetic and environmental influences on successful aging outcomes. Application of such methods can clarify the interplay of genes, environments, personality, and successful aging.

Krueger, Robert F.; South, Susan C.; Gruenewald, Tara L.; Seeman, Teresa E.; Roberts, Brent W.

2012-01-01

129

Gene-environment interactions and health inequalities: views of underserved communities.  

PubMed

This article examines the beliefs and experiences of individuals living in underserved ethnically diverse communities in Cleveland, Ohio, regarding the influence of genetic, social, and environmental factors on health and health inequalities. Using a community-engaged methodological approach, 13 focus groups were conducted with African American, Hispanic, and White individuals residing in the Cleveland area to explore attitudes and beliefs about genetics, genetic research, and health disparities and inequalities. Results of this study highlight the range of meanings that individuals attach to genetic variation, genomic research, and gene-environment interactions, and their implications for addressing health inequalities. The majority of participants in all focus groups reported that social and environmental factors were more important than genetics in contributing to health inequalities. Most participants were unfamiliar with genetic research. These data have implications for how genetic information and research might be applied in conjunction with addressing social determinants of health to improve prevention strategies in underserved communities and ultimately reduce health inequalities. PMID:23494820

Goldenberg, Aaron J; Hartmann, Christopher D; Morello, Laura; Brooks, Sanjur; Colón-Zimmermann, Kari; Marshall, Patricia A

2013-03-15

130

CHRM2, parental monitoring, and adolescent externalizing behavior: evidence for gene-environment interaction.  

PubMed

Psychologists, with their long-standing tradition of studying mechanistic processes, can make important contributions to further characterizing the risk associated with genes identified as influencing risk for psychiatric disorders. We report one such effort with respect to CHRM2, which codes for the cholinergic muscarinic 2 receptor and was of interest originally for its association with alcohol dependence. We tested for association between CHRM2 and prospectively measured externalizing behavior in a longitudinal, community-based sample of adolescents, as well as for moderation of this association by parental monitoring. We found evidence for an interaction in which the association between the genotype and externalizing behavior was stronger in environments with lower parental monitoring. There was also suggestion of a crossover effect, in which the genotype associated with the highest levels of externalizing behavior under low parental monitoring had the lowest levels of externalizing behavior at the extreme high end of parental monitoring. The difficulties involved in distinguishing mechanisms of gene-environment interaction are discussed. PMID:21441226

Dick, Danielle M; Meyers, Jacquelyn L; Latendresse, Shawn J; Creemers, Hanneke E; Lansford, Jennifer E; Pettit, Gregory S; Bates, John E; Dodge, Kenneth A; Budde, John; Goate, Alison; Buitelaar, Jan K; Ormel, Johannes; Verhulst, Frank C; Huizink, Anja C

2011-03-24

131

REVIEW: Genome-wide findings in schizophrenia and the role of gene-environment interplay.  

PubMed

The recent advent of genome-wide mass-marker technology has resulted in renewed optimism to unravel the genetic architecture of psychotic disorders. Genome-wide association studies have identified a number of common polymorphisms robustly associated with schizophrenia, in ZNF804A, transcription factor 4, major histocompatibility complex, and neurogranin. In addition, copy number variants (CNVs) in 1q21.1, 2p16.3, 15q11.2, 15q13.3, 16p11.2, and 22q11.2 were convincingly implicated in schizophrenia risk. Furthermore, these studies have suggested considerable genetic overlap with bipolar disorder (particularly for common polymorphisms) and neurodevelopmental disorders such as autism (particularly for CNVs). The influence of these risk variants on relevant intermediate phenotypes needs further study. In addition, there is a need for etiological models of psychosis integrating genetic risk with environmental factors associated with the disorder, focusing specifically on environmental impact on gene expression (epigenetics) and convergence of genes and environment on common biological pathways bringing about larger effects than those of genes or environment in isolation (gene-environment interaction). Collaborative efforts that bring together expertise in statistics, genetics, epidemiology, experimental psychiatry, brain imaging, and clinical psychiatry will be required to succeed in this challenging task. PMID:20553308

Van Winkel, Ruud; Esquivel, Gabriel; Kenis, Gunter; Wichers, Marieke; Collip, Dina; Peerbooms, Odette; Rutten, Bart; Myin-Germeys, Inez; Van Os, Jim

2010-06-11

132

Gene-environment interactions in the etiology of obesity: defining the fundamentals.  

PubMed

The concept of gene-environment interaction refers to a situation where the response or the adaptation to an environmental factor, a behavior, or a change in behavior is conditional on the genotype of the individual. Of particular interest for our understanding of the etiology of human obesity is the role played by genotype-nutrition and genotype-physical activity interactions. Evidence for the presence of such interaction effects affecting body mass and body composition comes from experimental studies undertaken with pairs of monozygotic twins and with nuclear families. These studies reveal that there are large individual differences in the responsiveness to well-defined energy balance manipulations. Overfeeding as well as negative energy balance protocols indicate that the response to these standardized experimental treatments is strongly influenced by one's genetic background. The genes that are responsible for the individual differences in the sensitivity to alterations in energy balance remain to be fully identified. They are likely to be numerous considering the complexity of the biological systems that are involved in body weight regulation. A number of research designs and technologies are available to identify these genes and to delineate the nature and the extent of the genetic polymorphisms involved. It was the purpose of the workshop to define the conditions under which gene-behavior interaction effects of relevance to human obesity could be reliably identified. PMID:19037213

Bouchard, Claude

2008-12-01

133

Gene-Environment Interaction and Covariation in Schizophrenia: The Role of Obstetric Complications  

PubMed Central

While genetic factors account for a significant proportion of liability to schizophrenia, a body of evidence attests to a significant environmental contribution. Understanding the mechanisms through which genetic and environmental factors coalesce in influencing schizophrenia is critical for elucidating the pathways underlying psychotic illness and for developing primary prevention strategies. Although obstetric complications (OCs) remain among the most well-documented environmental indicators of risk for schizophrenia, the pathogenic role they play in the etiology of schizophrenia continues to remain poorly understood. A question of major importance is do these factors result from a genetic diathesis to schizophrenia (as in gene-environment covariation), act additively or interactively with predisposing genes for the disorder in influencing disease risk, or independently cause disease onset? In this review, we evaluate 3 classes of OCs commonly related to schizophrenia including hypoxia-associated OCs, maternal infection during pregnancy, and maternal stress during pregnancy. In addition, we discuss several mechanisms by which OCs impact on genetically susceptible brain regions, increasing constitutional vulnerability to neuromaturational events and stressors later in life (ie, adolescence), which may in turn contribute to triggering psychosis.

Mittal, Vijay A.; Ellman, Lauren M.; Cannon, Tyrone D.

2008-01-01

134

Identification of gene-environment interactions in cancer studies using penalization.  

PubMed

High-throughput cancer studies have been extensively conducted, searching for genetic markers associated with outcomes beyond clinical and environmental risk factors. Gene-environment interactions can have important implications beyond main effects. The commonly-adopted single-marker analysis cannot accommodate the joint effects of a large number of markers. The existing joint-effects methods also have limitations. Specifically, they may suffer from high computational cost, do not respect the "main effect, interaction" hierarchical structure, or use ineffective techniques. We develop a penalization method for the identification of important G×E interactions and main effects. It has an intuitive formulation, respects the hierarchical structure, accommodates the joint effects of multiple markers, and is computationally affordable. In numerical study, we analyze prognosis data under the AFT (accelerated failure time) model. Simulation shows satisfactory performance of the proposed method. Analysis of an NHL (non-Hodgkin lymphoma) study with SNP measurements shows that the proposed method identifies markers with important implications and satisfactory prediction performance. PMID:23994599

Liu, Jin; Huang, Jian; Zhang, Yawei; Lan, Qing; Rothman, Nathaniel; Zheng, Tongzhang; Ma, Shuangge

2013-08-29

135

Gene-environment interactions in the aetiology of systemic lupus erythematosus.  

PubMed

Systemic lupus erythematosus (SLE) is a disease that displays a multitude of symptoms and a vast array of autoantibodies. The disease course may vary substantially between patients. The current understanding of SLE aetiology includes environmental factors acting on a genetically prone individual during an undetermined time period resulting in autoimmunity and finally surpassing that individual's disease threshold. Genetic differences and environmental factors may interact specifically in the pathogenetic processes and may influence disease development and modify the disease course. Identification of these factors and their interactions in the pathogenesis of SLE is vital in understanding the disease and may contribute to identify new treatment targets and perhaps also aid in disease prevention. However, there are several problems that need to be overcome, such as the protracted time frame of environmental influence, time dependent epigenetic alterations and the possibility that different pathogenetic pathways may result in a similar disease phenotype. This is mirrored by the relatively few studies that suggest specific gene-environment interactions. These include an association between SLE diagnosis and glutation S-transferase gene variants combined with occupational sun exposure as well as variants of the N-acetyl transferase gene in combination with either aromatic amine exposure or hydralazine. With increased knowledge on SLE pathogenesis, the role of environmental factors and their genetic interactions may be further elucidated. PMID:18075795

Jönsen, Andreas; Bengtsson, Anders A; Nived, Ola; Truedsson, Lennart; Sturfelt, Gunnar

2007-12-01

136

Gene-environment interactions: early life stress and risk for depressive and anxiety disorders  

PubMed Central

Rationale Prior reviews have examined how stress, broadly defined, interacts with genetic diathesis in the pathogenesis of internalizing (i.e., depressive and anxiety) disorders. Recent findings have suggested a unique role for early life stress (ELS) in the development of internalizing disorders, contributing to the rapid proliferation of research in this area. Objective This paper critically reviews studies in humans examining gene–environment interaction (GxE) effects of ELS on the risk for depression and anxiety, primarily from a candidate gene perspective. Major methodological challenges that are unique to such studies are considered. Results The majority of published studies have focused on candidates that regulate the serotonin system, especially the serotonin transporter. More recent work has addressed interactions of ELS with candidates from the hypothalamic-pituitary-adrenal axis and neurotrophin system. Available studies vary greatly with respect to definitions of ELS, examination of gene–gene interactions, consideration of gender effects, and attention to analytic limitations. Conclusions Overall, there is support for GxE effects of ELS on the risk for depressive and anxiety outcomes. Future studies of ELS in this context will require careful attention to methodologic considerations. Such studies would benefit from more systematic assessment of positive environmental factors (e.g., social support) and greater utilization of developmentally sensitive paradigms.

Tyrka, Audrey R.; Carpenter, Linda L.; Price, Lawrence H.

2013-01-01

137

Correlation of serum IgG concentration in foals and refractometry index of the dam's pre- and post-parturient colostrums: an assessment for failure of passive transfer in foals.  

PubMed

The object of this study was to evaluate the usefulness of measuring the differences in the values of the serum total protein (DVSTP) concentration of foals and the refractometry index (DVRI) of the milk of dams before and after nursing of the colostrum for assessing failure of passive transfer (FPT) in foals. Serum samples from 31 foals were collected before the first nursing and other 1 to 6 times between 4 and 24 hr after birth. Paired colostrum and milk samples were collected from 14 of their dams at the same time. Serum samples were analyzed for IgG concentration using a single radial immunodiffusion (SRID) test (98 samples) and total protein concentration using a temperature-compensating refractometer (98 samples). Colostrum and milk samples were analyzed for refractometry index (RI) using a Brix refractometer (71 samples). DVSTP concentration and DVRI were significantly correlated with serum IgG concentration. The negative predictive values (NPVs) of DVSTP concentration for detecting serum IgG concentrations<400 mg/dl and<800 mg/dl were 98.2% and 91.3% when the cutoff value is set to 0.4 mg/dl and 0.8 mg/dl, respectively. Furthermore, the NPVs of DVRI for detecting serum IgG concentrations<400 mg/dl and<800 mg/dl were 97.3% and 96.3% when the cutoff value is set to 6% and 10%, respectively. The results suggest that measurement of DVRI is useful in assessing FPT as an initial "stall-side" screening test, because it is easy, inexpensive to perform and allows for rapid interpretation. PMID:22785030

Korosue, Kenji; Murase, Harutaka; Sato, Fumio; Ishimaru, Mutsuki; Kotoyori, Yasumitsu; Nambo, Yasuo

2012-06-08

138

DISC1 mouse models as a tool to decipher gene-environment interactions in psychiatric disorders  

PubMed Central

DISC1 was discovered in a Scottish pedigree in which a chromosomal translocation that breaks this gene segregates with psychiatric disorders, mainly depression and schizophrenia. Linkage and association studies in diverse populations support DISC1 as a susceptibility gene to a variety of neuropsychiatric disorders. Many Disc1 mouse models have been generated to study its neuronal functions. These mouse models display variable phenotypes, some of them relevant to schizophrenia, others to depression. The Disc1 mouse models are popular genetic models for studying gene-environment interactions in schizophrenia. Five different Disc1 models have been combined with environmental factors. The environmental stressors employed can be classified as either early immune activation or later social paradigms. These studies cover major time points along the neurodevelopmental trajectory: prenatal, early postnatal, adolescence, and adulthood. Various combinations of molecular, anatomical and behavioral methods have been used to assess the outcomes. Additionally, three of the studies sought to rescue the resulting abnormalities. Here we provide background on the environmental paradigms used, summarize the results of these studies combining Disc1 mouse models with environmental stressors and discuss what we can learn and how to proceed. A major question is how the genetic and environmental factors determine which psychiatric disorder will be clinically manifested. To address this we can take advantage of the many Disc1 models available and expose them to the same environmental stressor. The complementary experiment would be to expose the same model to different environmental stressors. DISC1 is an ideal gene for this approach, since in the Scottish pedigree the same chromosomal translocation results in different psychiatric conditions.

Cash-Padgett, Tyler; Jaaro-Peled, Hanna

2013-01-01

139

Sleep Duration and Body Mass Index in Twins: A Gene-Environment Interaction  

PubMed Central

Study Objectives: To examine whether sleep duration modifies genetic and environmental influences on body mass index (BMI). Design: Genotype-environment interaction twin study. Setting: University of Washington Twin Registry. Patients or Participants: A population-based sample of US twins (1,088 pairs, 604 monozygotic, 484 dizygotic; 66% female; mean age = 36.6 yr, standard deviation (SD) = 15.9 yr). Interventions: N/A. Measurements and Results: Participants self-reported information on height, weight, and sleep. Mean BMI was calculated as 25.3 kg/m2 (SD = 5.4) and mean habitual sleep duration was 7.2 hr/night (SD = 1.2). Data were analyzed using biometric genetic interaction models. Overall the heritability of sleep duration was 34%. Longer sleep duration was associated with decreased BMI (P < 0.05). The heritability of BMI when sleep duration was < 7 hr (h2 = 70%) was more than twice as large as the heritability of BMI when sleep duration was ? 9 hr (h2 = 32%); this interaction was significant (P < 0.05). Conclusions: Shorter sleep duration is associated with increased BMI and increased genetic influences on BMI, suggesting that shorter sleep duration increases expression of genetic risks for high body weight. At the same time, longer sleep duration may suppress genetic influences on body weight. Future research aiming to identify specific genotypes for BMI may benefit by considering the moderating role of sleep duration. Citation: Watson NF; Harden KP; Buchwald D; Vitiello MV; Pack AI; Weigle DS; Goldberg J. Sleep duration and body mass index in twins: a gene-environment interaction. SLEEP 2012;35(5):597-603.

Watson, Nathaniel F.; Harden, Kathryn Paige; Buchwald, Dedra; Vitiello, Michael V.; Pack, Allan I.; Weigle, David S.; Goldberg, Jack

2012-01-01

140

Gene-Environment Interactions in the Development of Complex Disease Phenotypes  

PubMed Central

The lack of knowledge about the earliest events in disease development is due to the multi-factorial nature of disease risk. This information gap is the consequence of the lack of appreciation for the fact that most diseases arise from the complex interactions between genes and the environment as a function of the age or stage of development of the individual. Whether an environmental exposure causes illness or not is dependent on the efficiency of the so-called “environmental response machinery” (i.e., the complex of metabolic pathways that can modulate response to environmental perturbations) that one has inherited. Thus, elucidating the causes of most chronic diseases will require an understanding of both the genetic and environmental contribution to their etiology. Unfortunately, the exploration of the relationship between genes and the environment has been hampered in the past by the limited knowledge of the human genome, and by the inclination of scientists to study disease development using experimental models that consider exposure to a single environmental agent. Rarely in the past were interactions between multiple genes or between genes and environmental agents considered in studies of human disease etiology. The most critical issue is how to relate exposure-disease association studies to pathways and mechanisms. To understand how genes and environmental factors interact to perturb biological pathways to cause injury or disease, scientists will need tools with the capacity to monitor the global expression of thousands of genes, proteins and metabolites simultaneously. The generation of such data in multiple species can be used to identify conserved and functionally significant genes and pathways involved in gene-environment interactions. Ultimately, it is this knowledge that will be used to guide agencies such as the U.S. Department of Health and Human Services in decisions regarding biomedical research funding and policy.

Ramos, Rosemarie G.; Olden, Kenneth

2008-01-01

141

B4-1: An Overview of Kaiser Permanente's Research Program on Genes, Environment, and Health.  

PubMed

Background/Aims The Research Program on Genes, Environment, and Health (RPGEH) is a large, population-based resource for genetic epidemiology developed by scientists at the Kaiser Permanente (KP) Northern California Division of Research. The goal of this program is to link research data for 500,000 broadly consented health plan members, including longitudinal electronic medical records (EMR), genomic data from biospecimens, and environmental exposure data from surveys and geographic information system (GIS) databases in order to support research on many different health conditions. Methods In 2011, the RPGEH established a state-of-the-art biorepository. The KP clinical lab infrastructure is used to collect and transfer blood samples to the biorepository where saliva, serum, plasma, buffy coat and extracted DNA samples are processed and archived. The biorepository includes a facility for separating blood into components for storage, as well as DNA extraction and normalization. Storage capabilities include -80 C and -20 C freezers, an ambient storage unit and LN2 freezers. The biorepository was designed to store blood components for up to 500,000 health plan members. Although initially participant recruitment was by postal mail, electronic methods of recruitment have now been developed. The goal of this effort was to decrease the per person cost of contact and to recruit younger members. By leveraging the KP EMR, blood draw orders are now automatically entered by RPGEH staff for consenting participants. These samples are then stored in the RPGEH biorepository and tracked in a Laboratory Information Management System. Results A survey of adult health plan members has provided data on health-related behaviors and other risk factors for 430,000 RPGEH participants. To date, 190,000 biospecimens from consenting RPGEH participants have been collected. Genome-wide genotyping and telomere length analysis of 100,000 RPGEH participants have been performed. Conclusions At >200,000 participants (with specimens for >100,000 genotyped), the RPGEH is already an extremely unique and valuable resource. PMID:24085930

Schaefer, Cathy; Rowell, Sarah; Henderson, Mary; Walter, Lawrence; Sadler, Marianne; Miles, Sunita; Schaffer, Donna; Croen, Lisa; Jorgenson, Eric; Kushi, Lawrence; Quesenberry, Charles

2013-09-01

142

B4-1: An Overview of Kaiser Permanente's Research Program on Genes, Environment, and Health  

PubMed Central

Background/Aims The Research Program on Genes, Environment, and Health (RPGEH) is a large, population-based resource for genetic epidemiology developed by scientists at the Kaiser Permanente (KP) Northern California Division of Research. The goal of this program is to link research data for 500,000 broadly consented health plan members, including longitudinal electronic medical records (EMR), genomic data from biospecimens, and environmental exposure data from surveys and geographic information system (GIS) databases in order to support research on many different health conditions. Methods In 2011, the RPGEH established a state-of-the-art biorepository. The KP clinical lab infrastructure is used to collect and transfer blood samples to the biorepository where saliva, serum, plasma, buffy coat and extracted DNA samples are processed and archived. The biorepository includes a facility for separating blood into components for storage, as well as DNA extraction and normalization. Storage capabilities include ?80 C and ?20 C freezers, an ambient storage unit and LN2 freezers. The biorepository was designed to store blood components for up to 500,000 health plan members. Although initially participant recruitment was by postal mail, electronic methods of recruitment have now been developed. The goal of this effort was to decrease the per person cost of contact and to recruit younger members. By leveraging the KP EMR, blood draw orders are now automatically entered by RPGEH staff for consenting participants. These samples are then stored in the RPGEH biorepository and tracked in a Laboratory Information Management System. Results A survey of adult health plan members has provided data on health-related behaviors and other risk factors for 430,000 RPGEH participants. To date, 190,000 biospecimens from consenting RPGEH participants have been collected. Genome-wide genotyping and telomere length analysis of 100,000 RPGEH participants have been performed. Conclusions At >200,000 participants (with specimens for >100,000 genotyped), the RPGEH is already an extremely unique and valuable resource.

Schaefer, Cathy; Rowell, Sarah; Henderson, Mary; Walter, Lawrence; Sadler, Marianne; Miles, Sunita; Schaffer, Donna; Croen, Lisa; Jorgenson, Eric; Kushi, Lawrence; Quesenberry, Charles

2013-01-01

143

Characterization of gene-environment interactions for colorectal cancer susceptibility loci.  

PubMed

Genome-wide association studies (GWAS) have identified more than a dozen loci associated with colorectal cancer (CRC) risk. Here, we examined potential effect-modification between single-nucleotide polymorphisms (SNP) at 10 of these loci and probable or established environmental risk factors for CRC in 7,016 CRC cases and 9,723 controls from nine cohort and case-control studies. We used meta-analysis of an efficient empirical-Bayes estimator to detect potential multiplicative interactions between each of the SNPs [rs16892766 at 8q23.3 (EIF3H/UTP23), rs6983267 at 8q24 (MYC), rs10795668 at 10p14 (FLJ3802842), rs3802842 at 11q23 (LOC120376), rs4444235 at 14q22.2 (BMP4), rs4779584 at 15q13 (GREM1), rs9929218 at 16q22.1 (CDH1), rs4939827 at 18q21 (SMAD7), rs10411210 at 19q13.1 (RHPN2), and rs961253 at 20p12.3 (BMP2)] and select major CRC risk factors (sex, body mass index, height, smoking status, aspirin/nonsteroidal anti-inflammatory drug use, alcohol use, and dietary intake of calcium, folate, red meat, processed meat, vegetables, fruit, and fiber). The strongest statistical evidence for a gene-environment interaction across studies was for vegetable consumption and rs16892766, located on chromosome 8q23.3, near the EIF3H and UTP23 genes (nominal P(interaction) = 1.3 × 10(-4); adjusted P = 0.02). The magnitude of the main effect of the SNP increased with increasing levels of vegetable consumption. No other interactions were statistically significant after adjusting for multiple comparisons. Overall, the association of most CRC susceptibility loci identified in initial GWAS seems to be invariant to the other risk factors considered; however, our results suggest potential modification of the rs16892766 effect by vegetable consumption. PMID:22367214

Hutter, Carolyn M; Chang-Claude, Jenny; Slattery, Martha L; Pflugeisen, Bethann M; Lin, Yi; Duggan, David; Nan, Hongmei; Lemire, Mathieu; Rangrej, Jagadish; Figueiredo, Jane C; Jiao, Shuo; Harrison, Tabitha A; Liu, Yan; Chen, Lin S; Stelling, Deanna L; Warnick, Greg S; Hoffmeister, Michael; Küry, Sébastien; Fuchs, Charles S; Giovannucci, Edward; Hazra, Aditi; Kraft, Peter; Hunter, David J; Gallinger, Steven; Zanke, Brent W; Brenner, Hermann; Frank, Bernd; Ma, Jing; Ulrich, Cornelia M; White, Emily; Newcomb, Polly A; Kooperberg, Charles; LaCroix, Andrea Z; Prentice, Ross L; Jackson, Rebecca D; Schoen, Robert E; Chanock, Stephen J; Berndt, Sonja I; Hayes, Richard B; Caan, Bette J; Potter, John D; Hsu, Li; Bézieau, Stéphane; Chan, Andrew T; Hudson, Thomas J; Peters, Ulrike

2012-02-24

144

Characterization of gene-environment interactions for colorectal cancer susceptibility loci  

PubMed Central

Genome-wide association studies (GWAS) have identified over a dozen loci associated with colorectal cancer (CRC) risk. Here we examined potential effect-modification between single nucleotide polymorphisms (SNPs) at 10 of these loci and probable or established environmental risk factors for CRC in 7,016 CRC cases and 9,723 controls from nine cohort and case-control studies. We used meta-analysis of an efficient empirical-Bayes estimator to detect potential multiplicative interactions between each of the SNPs [rs16892766 at 8q23.3 (EIF3H/UTP23); rs6983267 at 8q24 (MYC); rs10795668 at 10p14 (FLJ3802842); rs3802842 at11q23 (LOC120376); rs4444235 at 14q22.2 (BMP4); rs4779584 at15q13 (GREM1); rs9929218 at16q22.1 (CDH1); rs4939827 at18q21 (SMAD7); rs10411210 at19q13.1 (RHPN2); and rs961253 at 20p12.3 (BMP2)] and select major CRC risk factors (sex, body mass index, height, smoking status, aspirin/non-steroidal anti-inflammatory drug use, alcohol use, and dietary intake of calcium, folate, red meat, processed meat, vegetables, fruit, and fiber). The strongest statistical evidence for a gene-environment interaction across studies was for vegetable consumption and rs16892766, located on chromosome 8q23.3, near the EIF3H and UTP23 genes (nominal p-interaction =1.3×10–4; adjusted p-value 0.02). The magnitude of the main effect of the SNP increased with increasing levels of vegetable consumption. No other interactions were statistically significant after adjusting for multiple comparisons. Overall, the association of most CRC susceptibility loci identified in initial GWAS appears to be invariant to the other risk factors considered; however, our results suggest potential modification of the rs16892766 effect by vegetable consumption.

Hutter, Carolyn M.; Chang-Claude, Jenny; Slattery, Martha L.; Pflugeisen, Bethann M.; Lin, Yi; Duggan, David; Nan, Hongmei; Lemire, Mathieu; Rangrej, Jagadish; Figueiredo, Jane C.; Jiao, Shuo; Harrison, Tabitha A.; Liu, Yan; Chen, Lin S.; Stelling, Deanna L.; Warnick, Greg S.; Hoffmeister, Michael; Kury, Sebastien; Fuchs, Charles S.; Giovannucci, Edward; Hazra, Aditi; Kraft, Peter; Hunter, David J.; Gallinger, Steven; Zanke, Brent W.; Brenner, Hermann; Frank, Bernd; Ma, Jing; Ulrich, Cornelia M.; White, Emily; Newcomb, Polly A.; Kooperberg, Charles; LaCroix, Andrea Z.; Prentice, Ross L.; Jackson, Rebecca D.; Schoen, Robert E.; Chanock, Stephen J.; Berndt, Sonja I.; Hayes, Richard B.; Caan, Bette J.; Potter, John D.; Hsu, Li; Bezieau, Stephane; Chan, Andrew T.; Hudson, Thomas J.; Peters, Ulrike

2012-01-01

145

Powerful Cocktail Methods for Detecting Genome-wide Gene-Environment Interaction  

PubMed Central

Identifying gene and environment interaction (GxE) can provide insights into biological networks of complex diseases, identify novel genes that act synergistically with environmental factors, and inform risk prediction. However, despite the fact that hundreds of novel disease-associated loci have been identified from genome-wide association studies (GWAS), few GxEs have been discovered. One reason is that most studies are underpowered for detecting these interactions. Several new methods have been proposed to improve power for GxE analysis, but performance varies with scenario. In this article we present a module-based approach to integrating various methods that exploits each method’s most appealing aspects. There are three modules in our approach: 1) a screening module for prioritizing SNPs; 2) a multiple comparison module for testing GxE; and 3) a GxE testing module. We combine all three of these modules and develop two novel “cocktail” methods. We demonstrate that the proposed cocktail methods maintain the type I error, and that the power tracks well with the best existing methods, despite that the best methods may be different under various scenarios and interaction models. For GWAS, where the true interaction models are unknown, methods like our “cocktail” methods that are powerful under a wide range of situations are particularly appealing. Broadly speaking, the modular approach is conceptually straightforward and computationally simple. It builds on common test statistics and is easily implemented without additional computational efforts. It also allows for an easy incorporation of new methods as they are developed. Our work provides a comprehensive and powerful tool for devising effective strategies for genome-wide detection of gene-environment interactions.

Hsu, Li; Jiao, Shuo; Dai, James Y.; Hutter, Carolyn; Peters, Ulrike; Kooperberg, Charles

2013-01-01

146

The challenge of causal inference in gene-environment interaction research: leveraging research designs from the social sciences.  

PubMed

The integration of genetics and the social sciences will lead to a more complex understanding of the articulation between social and biological processes, although the empirical difficulties inherent in this integration are large. One key challenge is the implications of moving "outside the lab" and away from the experimental tools available for research with model organisms. Social science research methods used to examine human behavior in nonexperimental, real-world settings to date have not been fully taken advantage of during this disciplinary integration, especially in the form of gene-environment interaction research. This article outlines and provides examples of several prominent research designs that should be used in gene-environment research and highlights a key benefit to geneticists of working with social scientists. PMID:23927518

Fletcher, Jason M; Conley, Dalton

2013-08-08

147

Passive solar underground home  

Microsoft Academic Search

A 2700 ft² passive solar, underground house is described. Dirt from a near-by swamp was used to berm the structure; 2 to 3 feet of dirt are piled on the roof. Glazing on the south side (200 ft²) provides passive solar heat as well as daylighting. The open design is described and illustrated. (MJJ)

Pauls

1978-01-01

148

Passive solar building design  

SciTech Connect

This book presents the basic principles of passive solar design and offers quantitative design aids in the form of microcomputer programs to stimulate innovative passive designs. These programs are unlike most others, which focus on conventional designs. The volume also covers landscaping, energy conservation and aesthetics.

Carter, C.; De Villiers, J.

1987-01-01

149

Electrode Passivation Studies.  

National Technical Information Service (NTIS)

Studies of the passivation of Zn-Fe, Zn-Mn, Zn-Co, and Zn-Ni alloys were made potentiostatically. Alloys of 90 Zn 10 Fe corrode at a high rate even when passive. Alloys of 83Zn-17 Mn have low, active dissolution currents. The 89 Zn - 11 Co alloys have hig...

S. B. Brummer A. C. Makrides J. Bradspies

1966-01-01

150

Teaching the Passive  

ERIC Educational Resources Information Center

|A discussion of teaching the passive voice in second language programs considers underlying attitudes toward grammar and grammar teaching. It is noted that Business German textbooks do not incorporate notions of the thought-to-grammar-pattern relationship, even though the passive voice appears twice as often in technical as in nontechnical…

Rockwood, Heidi

151

Passive walking with knees  

Microsoft Academic Search

It is shown that passive dynamic walking, a phenomenon originally described for bipeds having straight legs, also works with knees. Thus, giving only a downhill slope as a source of energy, a human-like pair of legs will settle into a natural gait generated by the passive interaction of gravity and inertia. No muscular input is required. The physics is much

T. McGeer

1990-01-01

152

Overcoming Passive Behavior.  

ERIC Educational Resources Information Center

|Passivity in learning disabled children is identified as either inborn or as "learned helplessness," and the role of the teacher in overcoming passivity is noted. Teachers can help students understand themselves, become active agents in learning, and use self monitoring devices. (CL)|

Kay, Marilyn

1986-01-01

153

Passive dispersal in arachnids  

Microsoft Academic Search

Some arachnids (spiders, mites and pseudoscorpions) are able to use both active and passive dispersal. The best-known passive dispersal method in arachnids is called ëballooningí and starts with ëtiptoe behaviourí. Using threads of silk, spiders can move from place to place with air currents. Usually the spider aeronauts are small, but sometimes larger ones can also be transported in this

DARIA BAJERLEIN

2007-01-01

154

Passive solar rowhouses  

SciTech Connect

This article discusses an urban renovation project in north Philadelphia using passive solar rowhouses to help revitalize the community. The topics covered include energy efficient building features; passive solar features; energy performance; costs; and improving performance designs. Project details are given.

Thayer, B.M.

1995-07-01

155

Electrode Passivation Studies.  

National Technical Information Service (NTIS)

The operation of primary, reserve batteries in a passive mode was explored. An anode can be put into the passive state by an appropriate electrical pulse and can be maintained in this condition by suitable connection to the positive battery electrode. Act...

S. B. Brummer A. C. Makrides A. J. Bradspies

1967-01-01

156

Is retinoic acid-related orphan receptor-alpha (RORA) a target for gene-environment interactions contributing to autism?  

PubMed

It is becoming increasingly clear that gene-environment interactions are risk factors for autism. However, there is limited information regarding the susceptibility of specific autism candidate genes to dysregulation by environmental factors, and even less information on the types of environmental agents that may lead to increased risk for autism. Based on our published studies, I propose that the demonstrated responsiveness of RORA to sex hormones makes it a prime target for disruption by endocrine disrupting compounds. PMID:22967355

Hu, Valerie W

2012-08-08

157

Passive solar construction handbook  

SciTech Connect

Many of the basic elements of passive solar design are reviewed. The unique design constraints presented in passive homes are introduced and many of the salient issues influencing design decisions are described briefly. Passive solar construction is described for each passive system type: direct gain, thermal storage wall, attached sunspace, thermal storage roof, and convective loop. For each system type, important design and construction issues are discussed and case studies illustrating designed and built examples of the system type are presented. Construction details are given and construction and thermal performance information is given for the materials used in collector components, storage components, and control components. Included are glazing materials, framing systems, caulking and sealants, concrete masonry, concrete, brick, shading, reflectors, and insulators. The Load Collector Ratio method for estimating passive system performance is appended, and other analysis methods are briefly summarized. (LEW)

Levy, E.; Evans, D.; Gardstein, C.

1981-08-01

158

Physics of passive solar buildings  

SciTech Connect

Primary emphasis in the paper is on methods of characterizing and analyzing passive solar buildings. Simplifying assumptions are described which make this analysis tractable without compromising significant accuracy or loss of insight into the basic physics of the situation. The overall nature of the mathematical simulation approach is described. Validation procedures based on data from test rooms and monitored buildings are outlined. Issues of thermal comfort are discussed. Simplified methods of analysis based on correlation procedures are reported and the nature of the economic conservation-solar optimization process is explored. Future trends are predicted.

Balcomb, J.D.

1981-01-01

159

Passive Infrared Resolution Target.  

National Technical Information Service (NTIS)

This patent describes a passive target array, for measuring the resolution of infrared reconnaissance sets, having a heat retaining background pad. A plurality of perforated aluminum strips are laid on the pad in a conventional photographic resolution tar...

L. O. Vroombout

1977-01-01

160

Nonlinear structure of escape-times to falls for a passive dynamic walker on an irregular slope: Anomaly detection using multi-class support vector machine and latent state extraction by canonical correlation analysis  

Microsoft Academic Search

Falls that occur during walking are a significant problem from the viewpoints of both medicine and robotics engineering. It is very important to predict falls in order to prevent the falls or minimize the ensuing damage from them. In this study, we investigate the structure of the escape-times from walking to falling of a passive dynamic biped walker on a

Hiromichi Suetani; Aiko M. Ideta; Jun Morimoto

2011-01-01

161

Passive fluorescence measurements during SIFLEX  

NASA Astrophysics Data System (ADS)

The goal of the participation of the LURE team to the SIFLEX campaign was %to provide clear evidence of quantitative absolute measurements of natural fluorescence andfluorescence flux evaluation by passive methods in the Fraunhofer lines. More specifically, to quantify the fluorescence flux in A and B absorption bands of atmospheric oxygen. The measurements have been focus on: Testing specific passive fluorescence instrumentation recently developed at LURE for assessing the sun induced fluorescence radiance from vegetation. Investigating diurnal and seasonal change of fluorescence and its behaviour with respect to plant condition, pigment content, global radiation amount and its correlation against accumulated biomass during growing period, Cross-correlate the fluorescence signal with hyperspectral reflectance and thermal IR radiance. A special attention has been paid to diurnal cycle and seasonal variations. Comparing fluorescence fluxes with CO2 fluxes measured by the already existing gas exchange equipment of the site. Instrumentation PMFD (Passive Multiwavelength Fluorescence Detector) was the main instrument used to asses fluorescence fluxes. The instrument was based on the Fraunhofer line principle, applied in the atmospheric oxygen A and B bands (760nm and 687nm, respectively). The output parameters were two stationary fluorescence flux at 687nm and 760nm and the NDVI (NDVI = (R760-R687) / (R760+R687)) index. Two additional channels of the instrument are devoted to measure reflectance variations at 531nm and 570 nm in order to calculate the PRI (PRI = (R531-R570) / (R531+R570)) index. This instrument was installed on the main tower, 10 m above the crown of the trees and maintained in the same viewing direction during the campaign (towards the north direction). The zenith angle was set to about 50-65 degrees. The footprint of the instrument contained the crowns of several trees. BD was a second passive detector operating solely in the atmospheric oxygen A band. It was used to complete the measurements of the PMFD instrument. It was installed on a tripod at 2 m above the ground and focused on a small tree in the vicinity of the tower. The instrument was used to explore fluorescence fluxes in correlation with a small lidar (LASERPAM) which measured the stationary fluorescence on the same footprint. In addition to the instrumentation for passive fluorescence measurements two lidar systems (FIPAM &LASERPAM) to better characterise the diurnal cycle of the sun induced fluorescence of the Scott pine forest (see accompanying presentation of Ounis et al. this meeting). A commercial LICOR 6400 IRGA system was also operated for punctual gas exchange measurements. More than 1 Gb of data as been collected which would require several months of work to be correctly evaluated. One original aspect of the campaign was the nature of the target constituted of the crowns of several Scott pines in different planes. The low density of the trees and the distribution of the needles on the volume of the target generated a situation very far for the usual approximation of the "big leaf" of a dense canopy. As a consequence the 760 nm radiation, which is well transmitted and well reflected generated unpredictable variations upon changes of solar radiation. More reliable results seems to be obtained using the 687 nm channel, as a consequence of the strong absorption of this wavelength. A rough examination of the PRI data showed interesting correlation, along the time series with the maximum electron flow of the photosystem II determined by variable fluorescence measurements.

Moya, I.; Ounis, A.; Louis, J.; Evain, S.; Ducruet, J.-M.

162

Gene-environment interactions of CETP gene variation in a high cardiovascular risk Mediterranean population[S  

PubMed Central

Genome-wide association studies show that cholesteryl ester transfer protein (CETP) single nucleotide polymorphisms (SNPs) are more strongly associated with HDL cholesterol (HDL-C) concentrations than any other loci across the genome. However, gene-environment interactions for clinical applications are still largely unknown. We studied gene-environment interactions between CETP SNPs and dietary fat intake, adherence to the Mediterranean diet, alcohol consumption, smoking, obesity, and diabetes on HDL-C in 4,210 high cardiovascular risk subjects from a Mediterranean population. We focused on the ?4,502C>T and the TaqIB SNPs in partial linkage disequilibrium (D'= 0.88; P < 0.001). They were independently associated with higher HDL-C (P < 0.001); this clinically relevant association was greater when their diplotype was considered (14% higher in TT/B2B2 vs. CC/B1B1). No gene-gene interaction was observed. We also analyzed the association of these SNPs with blood pressure, and no clinically relevant associations were detected. No statistically significant interactions of these SNPs with obesity, diabetes, and smoking in determining HDL-C concentrations were found. Likewise, alcohol, dietary fat, and adherence to the Mediterranean diet did not statistically interact with the CETP variants (independently or as diplotype) in determining HDL-C. In conclusion, the strong association of the CETP SNPs and HDL-C was not statistically modified by diet or by the other environmental factors.

Corella, Dolores; Carrasco, Paula; Fito, Montserrat; Martinez-Gonzalez, Miguel Angel; Salas-Salvado, Jordi; Aros, Fernando; Lapetra, Jose; Guillen, Marisa; Ortega-Azorin, Carolina; Warnberg, Julia; Fiol, Miquel; Ruiz-Gutierrez, Valentina; Serra-Majem, Lluis; Martinez, J. Alfredo; Ros, Emilio; Estruch, Ramon

2010-01-01

163

Cross-fostering and the extinction of cocaine's conditioned aversive effects: evidence for gene-environment interaction.  

PubMed

Although genetic and early environmental factors interact to affect drug abuse in humans, surprisingly few tractable laboratory animal models have been developed. Using reciprocal cross-fostering of the inbred Fischer and Lewis rat strains, we recently reported significant gene-environment interaction effects on responses to the aversive properties of 32 mg/kg subcutaneous cocaine, but only in females [Roma PG., Davis CM, Riley AL. Effects of cross-fostering on cocaine-induced conditioned taste aversions in Fischer and Lewis rats. Dev Psychobiol 2007;49:172-9]. The present study describes a follow-up analysis tracking the extinction of the equally acquired cocaine aversions in the adult male Fischer and Lewis rats raised by either Fischer or Lewis dams (n=11-12/group). Based on mean consumption, after eight saccharin-saline pairings, the in-fostered Fischer rats never extinguished while the Lewis animals fully extinguished; however, the cross-fostered Fischer rats partially extinguished, while extinction was completely suppressed in the cross-fostered Lewis animals. Based on documented strain differences in avoidance behavior and stress reactivity, the data were interpreted in terms of differential sensitivity to conditioned aversive stimulation. These data join other examples of cross-fostering effects on physiology and behavior in these strains and further support the use of the Fischer-Lewis model for exploring gene-environment interaction in drug-induced phenotypes. PMID:17651789

Roma, Peter G; Riley, Anthony L

2007-06-28

164

Method of passivating semiconductor surfaces  

DOEpatents

A method of passivating Group III-V or II-VI semiconductor compound surfaces. The method includes selecting a passivating material having a lattice constant substantially mismatched to the lattice constant of the semiconductor compound. The passivating material is then grown as an ultrathin layer of passivating material on the surface of the Group III-V or II-VI semiconductor compound. The passivating material is grown to a thickness sufficient to maintain a coherent interface between the ultrathin passivating material and the semiconductor compound. In addition, a device formed from such method is also disclosed.

Wanlass, Mark W. (Golden, CO)

1990-01-01

165

Passive solar retrofit guidebook  

SciTech Connect

The steps involved in retrofitting an existing building for passive solar heating are discussed, and include: conservation measures (increasing insulation and furnace efficiency and decreasing infiltration); site analysis for orientation, declination, and shading; glazing (including night insulation and overhangs); and thermal mass. A retrofit analysis is discussed along with details on each of four retrofit types - direct gain, thermal storage walls (Trombe walls and water walls), sunspaces, and thermosiphon air panel. Methods of calculating heat loss and solar retrofit performance are given and illustrated, as are methods of financial analysis, including payback period. Sources of financing are discussed. Marketing of passive solar retrofits is discussed and illustrated by a case study. (LEW)

Not Available

1981-01-01

166

Passive solar applications  

SciTech Connect

Passive solar applications in buildings are described. The major emphasis of the research has been on devising mathematical models to characterize heat flow within buildings, on the validation of these models by comparison with test results, and on the subsequent use of the models to investigate the influence of both various design parameters and the weather on system performance. Results from both test modules and monitored buildings are discussed. Simulation analysis, the development of simplified methods, and systems analysis are outlined. Passive solar potential in China is discussed.

Balcomb, J.D.

1985-01-01

167

Gene–Environment Interplay Helps to Explain Influences of Family Relationships on Adolescent Adjustment and Development  

Microsoft Academic Search

\\u000a It is clear that the family relationships have important and lasting ­influences on adolescent adjustment and development.\\u000a Genetically informed ­studies have provided additional information suggesting that these influences are due, at least in part,\\u000a to the interplay of genetic and environmental factors via genotype–environment correlation and interaction. Understanding\\u000a the relative contributions of genes and environment and how they operate together

Jenae M. Neiderhiser

168

Maternal passive smoking during pregnancy and neonatal health.  

PubMed

The objective of the study was the evaluation of effect of passive smoking among pregnant women on the health condition of their newborn babies. The study covered 150 healthy, non-smoking women from the Lublin Region. Among the total number of respondents, 45.34 % were not exposed during pregnancy to passive smoking at their workplace, while 13.33 % were passive smokers throughout the whole period of pregnancy. The state of their babies was assessed according to the APGAR Scale. A statistically significant correlation was noted between the maternal exposure to passive smoking during pregnancy and evaluation of the babies according to the APGAR Scale. No statistically significant relationship was noted between the date of delivery, the birth weight of babies, the onset of lactation, the problems with breastfeeding and maternal passive smoking during pregnancy. PMID:20047268

Wdowiak, Artur; Wiktor, Henryk; Wdowiak, Leszek

2009-12-01

169

Development of thermal performance criteria for residential passive solar buildings  

SciTech Connect

In support of the development of thermal performance criteria for residential passive solar buildings, thermal design characteristics and anticipated performance for 266 projects in the HUD Passive Residential Design Competition and the HUD Cycle 5 Demonstration Program were analyzed. These passive residences are located in all regions of the United States requiring space heating, and they represent a variety of passive solar system types including direct gain, indirect gain, and solarium (isolated gain) systems. The results of this statistical analysis are being used to develop proposed minimum acceptable levels of thermal performance for passive solar buildings for the residential performance criteria. A number of performance measures were examined, including net solar contribution, solar fraction, and auxiliary energy use. These and other design and climate-related parameters were statistically correlated using the DATAPLOT computer program and standard statistical analysis techniques.

Sabatiuk, P.A. (Mueller Associates, Baltimore, MD); Cassel, D.E.; McCabe, M.; Scarbrough, C.

1980-01-01

170

Exploiting gene-environment independence for analysis of case-control studies: an empirical Bayes-type shrinkage estimator to trade-off between bias and efficiency.  

PubMed

Standard prospective logistic regression analysis of case-control data often leads to very imprecise estimates of gene-environment interactions due to small numbers of cases or controls in cells of crossing genotype and exposure. In contrast, under the assumption of gene-environment independence, modern "retrospective" methods, including the "case-only" approach, can estimate the interaction parameters much more precisely, but they can be seriously biased when the underlying assumption of gene-environment independence is violated. In this article, we propose a novel empirical Bayes-type shrinkage estimator to analyze case-control data that can relax the gene-environment independence assumption in a data-adaptive fashion. In the special case, involving a binary gene and a binary exposure, the method leads to an estimator of the interaction log odds ratio parameter in a simple closed form that corresponds to an weighted average of the standard case-only and case-control estimators. We also describe a general approach for deriving the new shrinkage estimator and its variance within the retrospective maximum-likelihood framework developed by Chatterjee and Carroll (2005, Biometrika92, 399-418). Both simulated and real data examples suggest that the proposed estimator strikes a balance between bias and efficiency depending on the true nature of the gene-environment association and the sample size for a given study. PMID:18162111

Mukherjee, Bhramar; Chatterjee, Nilanjan

2007-12-20

171

Passive Buoyancy System.  

National Technical Information Service (NTIS)

The objective of the study is to procure one passive buoyancy system to meet the total requirements for 610,000 lbs. net buoyancy between 500 feet and 13,000 feet water depth. The total system may be comprised of one or more types of buoys, and if a combi...

1966-01-01

172

Passive Bipedal Running  

Microsoft Academic Search

Human-like running is a natural dynamic mode of a simple mechanical biped. Such a machine consists of two telescoping legs with linear springs, connected by a hip joint with a torsional spring. It will run passively; no pattern of forcing is required to generate the gait. With careful design its energy consumption can approach zero, but in any case the

Tad McGeer

1990-01-01

173

Polymeric passive laser shutters  

Microsoft Academic Search

Passive laser shutters are designed to control laser pulse duration by the regulation of the Q-factor through the use of substances which change in transparency upon exposure to light. The present paper outlines the development of such a shutter composed of a radiation-resistant modified polymethyl methacrylic matrix which may be filled with different clear dyes. Experiments performed using a nickel

D. A. Gromov; K. M. Diumaev; A. A. Manenkov; A. P. Masliukov; G. A. Matiushin; V. S. Nechitailo; A. M. Prokhorov

1982-01-01

174

Passive thermosiphon solar collector  

Microsoft Academic Search

A passive thermosiphon solar collector was designed, built, installed and tested under this grant. The basic premise was to design a simple system that was economical to build and easy to install as a retrofit to many similar homes in the local community. The module is comprised of a 2X4 frame with a sandwiched insert consisting of a flat black

1984-01-01

175

Passive hydrogel fuel generator  

SciTech Connect

A passive hydrogen oxygen generator in which the long wavelength infrared portion of the sun's spectrum heats water to provide circulation of the water within the generator. The shorter wavelength portion of the spectrum to which water is transparent is used in splitting water into hydrogen and oxygen by photoelectrolysis.

Neefe, Ch. W.

1985-04-16

176

Passive Dynamic Running  

Microsoft Academic Search

Previous work has considered how springy legs can improve the efficiency of the vertical motions of running, making them into resonant spring-mass oscillations that recycle energy from one step to the next. This paper considers how springy hips can be used to improve the efficiency of the legs' fore and aft swinging motions in running. We have studied a passive

Clay M. Thompson; Marc H. Raiber

1989-01-01

177

Passive Solar Heating Residences.  

National Technical Information Service (NTIS)

Passive solar heating systems can supply a major portion of a house's heating load if properly designed. The four basic concepts used are direct gain, thermal storage in wall or roof, solar greenhouse and convective loop. In most applications some of thes...

W. E. Olson

1979-01-01

178

(Passive Solar Heat). Final Report.  

National Technical Information Service (NTIS)

The overall purpose of the demonstration reported was to encourage consumers to use passive solar heat. There were four primary objectives: to document the effectiveness of a simple passive solar design; to demonstrate the feasibility of individual planni...

P. P. Gula

1981-01-01

179

Passive Ranging with Incoherent Systems.  

National Technical Information Service (NTIS)

Research Areas Include * Passive Ranging with a single image from a single- lens incoherent optical system * Extended Depth of Field Incoherent Optical Systems. ( i.e. passive ranging systems that operate over a very large object volume.) Specific Analysi...

W. Miceli W. T. Cathey E. R. Dowski A. FitzGerrell

1995-01-01

180

Use of the Twin Design to Examine Evocative Gene-Environment Effects within a Conversational Context  

PubMed Central

The purpose of this study was to highlight the role of twin designs in understanding children’s conversational interactions. Specifically, we (a) attempted to replicate the findings of genetic effects on children’s conversational language use reported in DeThorne et al. (2008), and (b) examined whether the language used by examiners in their conversation with twins reflected differences in the children’s genetic similarity. Behavioral genetic analyses included intraclass correlations and model fitting procedures applied to 514 same-sex twins (202 MZ, 294 DZ, 10 unknown zygosity) from the Western Reserve Reading Project (Petrill, Deater-Deckard, Thompson, DeThorne, & Schatschneider, 2006). Analyses focused on child and examiner measures of talkativeness, average utterance length, vocabulary diversity, and grammatical complexity from a fifteen-minute conversational exchange. Substantial genetic effects on children’s conversational language measures replicated results from DeThorne et al. (2008) using an expanded sample. However, no familiality was reflected in the examiner language measures. Modest phenotypic correlations between child and examiner language measures suggested that differences in examiner language use may elicit differences in child language use, but evidence of evocative rGE in which genetic differences across children evoke differences in examiner language use, was not found. The discussion focuses on a comparison of findings to previous studies and implications for future research.

DeThorne, Laura Segebart; Hart, Sara Ann

2010-01-01

181

A doubly robust test for gene-environment interaction in family-based studies of affected offspring  

PubMed Central

We develop a locally efficient test for (multiplicative) gene–environment interaction in family studies that collect genotypic information and environmental exposures for affected offspring along with genotypic information for their parents or relatives. The proposed test does not require modeling the effects of environmental exposures and is doubly robust in the sense of being valid if either a model for the main genetic effect holds or a model for the expected environmental exposure (given the offspring affection status and parental mating types) but not necessarily both. It extends the FBAT-I to allow for missing parental mating types and families of arbitrary size. Simulation studies and the analysis of an Alzheimer's disease study confirm the adequate performance of the proposed test.

Moerkerke, Beatrijs; Vansteelandt, Stijn; Lange, Christoph

2010-01-01

182

Gene-environment interaction testing in family-based association studies with phenotypically ascertained samples: a causal inference approach  

PubMed Central

We propose a method for testing gene–environment (G × E) interactions on a complex trait in family-based studies in which a phenotypic ascertainment criterion has been imposed. This novel approach employs G-estimation, a semiparametric estimation technique from the causal inference literature, to avoid modeling of the association between the environmental exposure and the phenotype, to gain robustness against unmeasured confounding due to population substructure, and to acknowledge the ascertainment conditions. The proposed test allows for incomplete parental genotypes. It is compared by simulation studies to an analogous conditional likelihood–based approach and to the QBAT-I test, which also invokes the G-estimation principle but ignores ascertainment. We apply our approach to a study of chronic obstructive pulmonary disorder.

Fardo, David W.; Liu, Jinze; Demeo, Dawn L.; Silverman, Edwin K.; Vansteelandt, Stijn

2012-01-01

183

Conceptual shifts needed to understand the dynamic interactions of genes, environment, epigenetics, social processes, and behavioral choices.  

PubMed

Social and behavioral research in public health is often intimately tied to profound, but frequently neglected, biological influences from underlying genetic, environmental, and epigenetic events. The dynamic interplay between the life, social, and behavioral sciences often remains underappreciated and underutilized in addressing complex diseases and disorders and in developing effective remediation strategies. Using a case-study format, we present examples as to how the inclusion of genetic, environmental, and epigenetic data can augment social and behavioral health research by expanding the parameters of such studies, adding specificity to phenotypic assessments, and providing additional internal control in comparative studies. We highlight the important roles of gene-environment interactions and epigenetics as sources of phenotypic change and as a bridge between the life and social and behavioral sciences in the development of robust interdisciplinary analyses. PMID:23927503

Jackson, Fatimah L C; Niculescu, Mihai D; Jackson, Robert T

2013-08-08

184

Conceptual Shifts Needed to Understand the Dynamic Interactions of Genes, Environment, Epigenetics, Social Processes, and Behavioral Choices  

PubMed Central

Social and behavioral research in public health is often intimately tied to profound, but frequently neglected, biological influences from underlying genetic, environmental, and epigenetic events. The dynamic interplay between the life, social, and behavioral sciences often remains underappreciated and underutilized in addressing complex diseases and disorders and in developing effective remediation strategies. Using a case-study format, we present examples as to how the inclusion of genetic, environmental, and epigenetic data can augment social and behavioral health research by expanding the parameters of such studies, adding specificity to phenotypic assessments, and providing additional internal control in comparative studies. We highlight the important roles of gene–environment interactions and epigenetics as sources of phenotypic change and as a bridge between the life and social and behavioral sciences in the development of robust interdisciplinary analyses.

Niculescu, Mihai D.; Jackson, Robert T.

2013-01-01

185

The Gene, Environment Association Studies Consortium (GENEVA): Maximizing the Knowledge Obtained from GWAS by Collaboration Across Studies of Multiple Conditions  

PubMed Central

Genome-wide association studies (GWAS) have emerged as powerful means for identifying genetic loci related to complex diseases. However, the role of environment and its potential to interact with key loci has not been adequately addressed in most GWAS. Networks of collaborative studies involving different study populations and multiple phenotypes provide a powerful approach for addressing the challenges in analysis and interpretation shared across studies. The Gene, Environment Association Studies (GENEVA) consortium was initiated to: identify genetic variants related to complex diseases; identify variations in gene-trait associations related to environmental exposures; and ensure rapid sharing of data through the database of Genotypes and Phenotypes. GENEVA consists of several academic institutions, including a coordinating center, two genotyping centers and 14 independently designed studies of various phenotypes, as well as several Institutes and Centers of the National Institutes of Health led by the National Human Genome Research Institute. Minimum detectable effect sizes include relative risks ranging from 1.24 to 1.57 and proportions of variance explained ranging from 0.0097 to 0.02. Given the large number of research participants (N > 80,000), an important feature of GENEVA is harmonization of common variables, which allow analyses of additional traits. Environmental exposure information available from most studies also enables testing of gene-environment interactions. Facilitated by its sizeable infrastructure for promoting collaboration, GENEVA has established a unified framework for genotyping, data quality control, analysis and interpretation. By maximizing knowledge obtained through collaborative GWAS incorporating environmental exposure information, GENEVA aims to enhance our understanding of disease etiology, potentially identifying opportunities for intervention.

Cornelis, Marilyn C.; Agrawal, Arpana; Cole, John W.; Hansel, Nadia N.; Barnes, Kathleen C.; Beaty, Terri H.; Bennett, Siiri N.; Bierut, Laura J.; Boerwinkle, Eric; Doheny, Kimberly F; Feenstra, Bjarke; Feingold, Eleanor; Fornage, Myriam; Haiman, Christopher A.; Harris, Emily L.; Hayes, M. Geoffrey; Heit, John A.; Hu, Frank B.; Kang, Jae H.; Laurie, Cathy C.; Ling, Hua; Manolio, Teri A.; Marazita, Mary L.; Mathias, Rasika A.; Mirel, Daniel B.; Paschall, Justin; Pasquale, Louis R.; Pugh, Elizabeth W.; Rice, John P.; Udren, Jenna; van Dam, Rob M.; Wang, Xiaojing; Wiggs, Janey L.; Williams, Kayleen; Yu, Kai

2010-01-01

186

Gene-Environment Interactions in Genome-Wide Association Studies: A Comparative Study of Tests Applied to Empirical Studies of Type 2 Diabetes  

PubMed Central

The question of which statistical approach is the most effective for investigating gene-environment (G-E) interactions in the context of genome-wide association studies (GWAS) remains unresolved. By using 2 case-control GWAS (the Nurses’ Health Study, 1976–2006, and the Health Professionals Follow-up Study, 1986–2006) of type 2 diabetes, the authors compared 5 tests for interactions: standard logistic regression-based case-control; case-only; semiparametric maximum-likelihood estimation of an empirical-Bayes shrinkage estimator; and 2-stage tests. The authors also compared 2 joint tests of genetic main effects and G-E interaction. Elevated body mass index was the exposure of interest and was modeled as a binary trait to avoid an inflated type I error rate that the authors observed when the main effect of continuous body mass index was misspecified. Although both the case-only and the semiparametric maximum-likelihood estimation approaches assume that the tested markers are independent of exposure in the general population, the authors did not observe any evidence of inflated type I error for these tests in their studies with 2,199 cases and 3,044 controls. Both joint tests detected markers with known marginal effects. Loci with the most significant G-E interactions using the standard, empirical-Bayes, and 2-stage tests were strongly correlated with the exposure among controls. Study findings suggest that methods exploiting G-E independence can be efficient and valid options for investigating G-E interactions in GWAS.

Cornelis, Marilyn C.; Tchetgen Tchetgen, Eric J.; Liang, Liming; Qi, Lu; Chatterjee, Nilanjan; Hu, Frank B.; Kraft, Peter

2012-01-01

187

Passive ranging sonar based on multi-beam towed array  

Microsoft Academic Search

In this paper we study passive range estimation using various beamformer for a linear hydrophone array. One common method of determining the time delay and, hence, the arrival angle relative to the sensors axis is to compute the cross correlation function. Because of the finite observation time, however, the cross correlation function cannot be precisely calculated. We make appropriate sub-arrays

Jun H. Kim; In S. Yang; Ki M. Kim; Won T. Oh

2000-01-01

188

Passive optoelectronic tag  

NASA Astrophysics Data System (ADS)

In response to a pressing demand for tagging systems and technologies developing, Physical Optics Corporation (POC) proposes a novel Passive Optoelectronical (POET) Tag system. The POET tag is an omnidirectional (360° in azimuth), with up to 180° field-of-view in elevation, retroreflection optical system with a high frequency multiple quantum well (MQW) light intensity modulator for free space IR optical communication. The POET tag optical scheme is a compact, high quality generalized fish-eye lens with telecentric arrangement in image space. The telecentric arrangement in image space provides perfect omnidirectional retroreflection of a recall beam and an optimum divergent of light at the MQW providing maximum modulation contrast ratios. The important POET tag features are low power consumption, zero probability of jamming and intercepting (high security of communication,) because it operates in a passive retroreflection mode with a highly-directed optical beam.

Agurok, Il'ya P.; Jannson, Tomasz P.; Savant, Gajendra D.

2003-09-01

189

Information-theoretic gene-gene and gene-environment interaction analysis of quantitative traits  

PubMed Central

Background The purpose of this research was to develop a novel information theoretic method and an efficient algorithm for analyzing the gene-gene (GGI) and gene-environmental interactions (GEI) associated with quantitative traits (QT). The method is built on two information-theoretic metrics, the k-way interaction information (KWII) and phenotype-associated information (PAI). The PAI is a novel information theoretic metric that is obtained from the total information correlation (TCI) information theoretic metric by removing the contributions for inter-variable dependencies (resulting from factors such as linkage disequilibrium and common sources of environmental pollutants). Results The KWII and the PAI were critically evaluated and incorporated within an algorithm called CHORUS for analyzing QT. The combinations with the highest values of KWII and PAI identified each known GEI associated with the QT in the simulated data sets. The CHORUS algorithm was tested using the simulated GAW15 data set and two real GGI data sets from QTL mapping studies of high-density lipoprotein levels/atherosclerotic lesion size and ultra-violet light-induced immunosuppression. The KWII and PAI were found to have excellent sensitivity for identifying the key GEI simulated to affect the two quantitative trait variables in the GAW15 data set. In addition, both metrics showed strong concordance with the results of the two different QTL mapping data sets. Conclusion The KWII and PAI are promising metrics for analyzing the GEI of QT.

2009-01-01

190

Passive fetal monitoring sensor  

NASA Astrophysics Data System (ADS)

An ambulatory, passive sensor for use in a fetal monitoring system is discussed. The invention is comprised of a piezoelectric polymer film, combined with a metallic mounting plate fastened to a belt, and electrically connected to a signal processing unit by means of a shielded cable. The purpose of the sensor is to receive pressure pulses emitted by a fetus inside an expectant mother. Additionally, the monitor will filter out pressure pulses arising from other sources, such as the maternal heart.

Zuckerwar, Allan J.; Hall, Earl T.; Baker, Donald A.; Bryant, Timothy D.

1992-08-01

191

Passive fetal monitoring sensor  

NASA Astrophysics Data System (ADS)

The invention is an ambulatory, passive sensor for use in a fetal monitoring system. The invention incorporates piezoelectric polymer film combined with a metallic mounting plate fastened to a belt and electrically connected to a signal processing unit by means of a shielded cable. The purpose of the sensor is to receive pressure pulses emitted from a fetus inside an expectant mother and to provide means for filtering out pressure pulses arising from other sources, such as the maternal heart.

1990-07-01

192

Nanoimprinted passive optical devices  

Microsoft Academic Search

We report on the feasibility and process parameters of nanoimprint lithography to fabricate low refractive index passive optical devices. Diffraction gratings printed in polymethylmethacrylate (PMMA) exhibit a sharp dispersion with a full width at half maximum of about 20 nm. Waveguides were printed in polystyrene (PS) on silicon oxide and had losses between 8-20 dB cm-1 at wavelengths between 650-400

J. Seekamp; S. Zankovych; A. H. Helfer; P. Maury; C. M. Sotomayor Torres; G. Böttger; C. Liguda; M. Eich; B. Heidari; L. Montelius; J. Ahopelto

2002-01-01

193

New Generalized Cross-Correlator.  

National Technical Information Service (NTIS)

A new Generalized Cross-Correlator (GCC) for the passive time delay estimation problem is presented. The interpretation of this GCC is that of estimating the cross-correlation function by cross-correlating the least mean square estimates of the signal com...

A. Hero S. C. Schwartz

1983-01-01

194

Passive Scalar in 2D Turbulence  

NASA Astrophysics Data System (ADS)

We examined the behavior of a passive scalar in a 2D turbulent flow and confirm the so-called Batchelor scaling. For large r, the second order structure function S2(r) = <(?(x+r) - ?(x))^2> ˜ log(r). For small r, S2(r) ˜ r^2. The logarithmic dependence of S2(r) is consistent with a power spectrum that goes as the inverse power of k, the wavenumber. These experiments are performed using a falling soap film as the 2D turbulent system and various colored dyes for the passive scalar, which is injected at a point. The decaying turbulence is generated using a comb oriented perpendicular to the film. It does not appear to matter whether the dye is injected above or below the comb. The measurements were made in the Eulerian frame at a single point. Time is then replaced by distance using the Taylor frozen turbulence hypothesis. The structure function is determined from the correlation function, which is calculated using a photon correlation scheme. The passive scalar measurements are compared with the behavior of thickness fluctuations in the soap film, which is another random variable.

Cerbus, Rory; Goldburg, Walter

2011-11-01

195

Paraoxonase gene variants are associated with autism in North America, but not in Italy: possible regional specificity in gene–environment interactions  

Microsoft Academic Search

Organophosphates (OPs) are routinely used as pesticides in agriculture and as insecticides within the household. Our prior work on Reelin and APOE delineated a gene–environment interactive model of autism pathogenesis, whereby genetically vulnerable individuals prenatally exposed to OPs during critical periods in neurodevelopment could undergo altered neuronal migration, resulting in an autistic syndrome. Since household use of OPs is far

M D'Amelio; I Ricci; R Sacco; X Liu; L D'Agruma; L A Muscarella; V Guarnieri; R Militerni; C Bravaccio; M Elia; C Schneider; R Melmed; S Trillo; T Pascucci; S Puglisi-Allegra; K-L Reichelt; F Macciardi; J J A Holden; A M Persico

2005-01-01

196

How much can a large population study on genes, environments, their interactions and common diseases contribute to the health of the American people?  

Microsoft Academic Search

I offer a critical perspective on a large-scale population study on gene–environment interactions and common diseases proposed by the US Secretary of Health and Human Services’ Advisory Committee on Genetics, Health, and Society (SACGHS). I argue that for scientific and policy reasons this and similar studies have little to add to current knowledge about how to prevent, treat, or decrease

Claudia Chaufan

2007-01-01

197

Fundamental studies of passivity and passivity breakdown. Final report  

SciTech Connect

This report summarizes the findings of our fundamental research program on passivity and passivity breakdown. During the past three and one half years in this program (including the three year incrementally-funded grant prior to the present grant), we developed and experimentally tested various physical models for the growth and breakdown of passive films on metal surfaces. These models belong to a general class termed ``point defects models`` (PDMs), in which the growth and breakdown of passive films are described in terms of the movement of anion and cation vacancies.

Macdonald, D.D.; Urquidi-Macdonald, M.; Song, H.; Biaggio-Rocha, S.; Searson, P.

1991-11-01

198

Passive Acoustic Techniques for Monitoring Ocean Dynamics  

NASA Astrophysics Data System (ADS)

Ambient noise in the ocean carries vast information about physical properties of the propagation medium, including sound speed and current velocity fields in the water column and geoacoustic parameters of the sea floor. Passive acoustic techniques utilize the ambient noise and sound sources of opportunity, such as shipping, to retrieve environmental information from measurements of acoustic pressure on hydrophone arrays without need for any controlled sound sources. Non-invasive nature of passive acoustic techniques and the types of the environmental characteristics these provide, combined with their low power requirements and the intrinsic needs for long observation times, near real-time access to data, and rather large data flows, make the passive acoustics ideally suited for incorporation into cabled ocean observatories. In this paper, we focus on retrieval of environmental parameters from the cross-correlation function of ambient noise. It is shown theoretically that, with the averaging time being sufficiently long, the two-point correlation function of diffuse ambient noise in an arbitrary inhomogeneous, moving medium contains as much information about the environment as can be obtained acoustically by placing transceivers in the two points. Thus, measurements of the noise cross-correlation allow one to quantify flow-induced acoustic non-reciprocity and evaluate both spatially averaged flow velocity and sound speed between the two points. Limitations are discussed which arise from the fact that ambient noise in the ocean is neither perfectly diffuse nor stationary. As an example of opportunities offered by coherent processing of ambient noise, we introduce the concept of a passive inverted echo sounder which would provide measurements of the heat content of the ocean and characterize the local internal gravity wave processes, much like conventional, active inverted echo sounders. Instead of radiating sound, the passive inverted echo sounder employs high-frequency acoustic noise generated by interaction and breaking of waves on the ocean surface as well as low-frequency noise from distant shipping to measure two-way acoustic travel times between near-bottom acoustic sensors and reflective ocean surface as well as scattering layers in the water column. The use of linear hydrophone arrays to decrease the necessary averaging times and improve accuracy of the correlation measurements of acoustic travel times will be discussed.

Godin, O. A.

2009-05-01

199

Evidence of Gene-Environment Interactions between Common Breast Cancer Susceptibility Loci and Established Environmental Risk Factors  

PubMed Central

Various common genetic susceptibility loci have been identified for breast cancer; however, it is unclear how they combine with lifestyle/environmental risk factors to influence risk. We undertook an international collaborative study to assess gene-environment interaction for risk of breast cancer. Data from 24 studies of the Breast Cancer Association Consortium were pooled. Using up to 34,793 invasive breast cancers and 41,099 controls, we examined whether the relative risks associated with 23 single nucleotide polymorphisms were modified by 10 established environmental risk factors (age at menarche, parity, breastfeeding, body mass index, height, oral contraceptive use, menopausal hormone therapy use, alcohol consumption, cigarette smoking, physical activity) in women of European ancestry. We used logistic regression models stratified by study and adjusted for age and performed likelihood ratio tests to assess gene–environment interactions. All statistical tests were two-sided. We replicated previously reported potential interactions between LSP1-rs3817198 and parity (Pinteraction?=?2.4×10?6) and between CASP8-rs17468277 and alcohol consumption (Pinteraction?=?3.1×10?4). Overall, the per-allele odds ratio (95% confidence interval) for LSP1-rs3817198 was 1.08 (1.01–1.16) in nulliparous women and ranged from 1.03 (0.96–1.10) in parous women with one birth to 1.26 (1.16–1.37) in women with at least four births. For CASP8-rs17468277, the per-allele OR was 0.91 (0.85–0.98) in those with an alcohol intake of <20 g/day and 1.45 (1.14–1.85) in those who drank ?20 g/day. Additionally, interaction was found between 1p11.2-rs11249433 and ever being parous (Pinteraction?=?5.3×10?5), with a per-allele OR of 1.14 (1.11–1.17) in parous women and 0.98 (0.92–1.05) in nulliparous women. These data provide first strong evidence that the risk of breast cancer associated with some common genetic variants may vary with environmental risk factors.

Nickels, Stefan; Truong, Therese; Hein, Rebecca; Stevens, Kristen; Buck, Katharina; Behrens, Sabine; Eilber, Ursula; Schmidt, Martina; Haberle, Lothar; Vrieling, Alina; Gaudet, Mia; Figueroa, Jonine; Schoof, Nils; Spurdle, Amanda B.; Rudolph, Anja; Fasching, Peter A.; Hopper, John L.; Makalic, Enes; Schmidt, Daniel F.; Southey, Melissa C.; Beckmann, Matthias W.; Ekici, Arif B.; Fletcher, Olivia; Gibson, Lorna; dos Santos Silva, Isabel; Peto, Julian; Humphreys, Manjeet K.; Wang, Jean; Cordina-Duverger, Emilie; Menegaux, Florence; Nordestgaard, B?rge G.; Bojesen, Stig E.; Lanng, Charlotte; Anton-Culver, Hoda; Ziogas, Argyrios; Bernstein, Leslie; Clarke, Christina A.; Brenner, Hermann; Muller, Heiko; Arndt, Volker; Stegmaier, Christa; Brauch, Hiltrud; Bruning, Thomas; Harth, Volker; The GENICA Network; Mannermaa, Arto; Kataja, Vesa; Kosma, Veli-Matti; Hartikainen, Jaana M.; kConFab; Group, AOCS Management; Lambrechts, Diether; Smeets, Dominiek; Neven, Patrick; Paridaens, Robert; Flesch-Janys, Dieter; Obi, Nadia; Wang-Gohrke, Shan; Couch, Fergus J.; Olson, Janet E.; Vachon, Celine M.; Giles, Graham G.; Severi, Gianluca; Baglietto, Laura; Offit, Kenneth; John, Esther M.; Miron, Alexander; Andrulis, Irene L.; Knight, Julia A.; Glendon, Gord; Mulligan, Anna Marie; Chanock, Stephen J.; Lissowska, Jolanta; Liu, Jianjun; Cox, Angela; Cramp, Helen; Connley, Dan; Balasubramanian, Sabapathy; Dunning, Alison M.; Shah, Mitul; Trentham-Dietz, Amy; Newcomb, Polly; Titus, Linda; Egan, Kathleen; Cahoon, Elizabeth K.; Rajaraman, Preetha; Sigurdson, Alice J.; Doody, Michele M.; Guenel, Pascal; Pharoah, Paul D. P.; Schmidt, Marjanka K.; Hall, Per; Easton, Doug F.; Garcia-Closas, Montserrat; Milne, Roger L.; Chang-Claude, Jenny

2013-01-01

200

Evidence of gene-environment interactions between common breast cancer susceptibility loci and established environmental risk factors.  

PubMed

Various common genetic susceptibility loci have been identified for breast cancer; however, it is unclear how they combine with lifestyle/environmental risk factors to influence risk. We undertook an international collaborative study to assess gene-environment interaction for risk of breast cancer. Data from 24 studies of the Breast Cancer Association Consortium were pooled. Using up to 34,793 invasive breast cancers and 41,099 controls, we examined whether the relative risks associated with 23 single nucleotide polymorphisms were modified by 10 established environmental risk factors (age at menarche, parity, breastfeeding, body mass index, height, oral contraceptive use, menopausal hormone therapy use, alcohol consumption, cigarette smoking, physical activity) in women of European ancestry. We used logistic regression models stratified by study and adjusted for age and performed likelihood ratio tests to assess gene-environment interactions. All statistical tests were two-sided. We replicated previously reported potential interactions between LSP1-rs3817198 and parity (Pinteraction = 2.4 × 10(-6)) and between CASP8-rs17468277 and alcohol consumption (Pinteraction = 3.1 × 10(-4)). Overall, the per-allele odds ratio (95% confidence interval) for LSP1-rs3817198 was 1.08 (1.01-1.16) in nulliparous women and ranged from 1.03 (0.96-1.10) in parous women with one birth to 1.26 (1.16-1.37) in women with at least four births. For CASP8-rs17468277, the per-allele OR was 0.91 (0.85-0.98) in those with an alcohol intake of <20 g/day and 1.45 (1.14-1.85) in those who drank ? 20 g/day. Additionally, interaction was found between 1p11.2-rs11249433 and ever being parous (Pinteraction = 5.3 × 10(-5)), with a per-allele OR of 1.14 (1.11-1.17) in parous women and 0.98 (0.92-1.05) in nulliparous women. These data provide first strong evidence that the risk of breast cancer associated with some common genetic variants may vary with environmental risk factors. PMID:23544014

Nickels, Stefan; Truong, Thérèse; Hein, Rebecca; Stevens, Kristen; Buck, Katharina; Behrens, Sabine; Eilber, Ursula; Schmidt, Martina; Häberle, Lothar; Vrieling, Alina; Gaudet, Mia; Figueroa, Jonine; Schoof, Nils; Spurdle, Amanda B; Rudolph, Anja; Fasching, Peter A; Hopper, John L; Makalic, Enes; Schmidt, Daniel F; Southey, Melissa C; Beckmann, Matthias W; Ekici, Arif B; Fletcher, Olivia; Gibson, Lorna; Silva, Isabel dos Santos; Peto, Julian; Humphreys, Manjeet K; Wang, Jean; Cordina-Duverger, Emilie; Menegaux, Florence; Nordestgaard, Børge G; Bojesen, Stig E; Lanng, Charlotte; Anton-Culver, Hoda; Ziogas, Argyrios; Bernstein, Leslie; Clarke, Christina A; Brenner, Hermann; Müller, Heiko; Arndt, Volker; Stegmaier, Christa; Brauch, Hiltrud; Brüning, Thomas; Harth, Volker; Mannermaa, Arto; Kataja, Vesa; Kosma, Veli-Matti; Hartikainen, Jaana M; Lambrechts, Diether; Smeets, Dominiek; Neven, Patrick; Paridaens, Robert; Flesch-Janys, Dieter; Obi, Nadia; Wang-Gohrke, Shan; Couch, Fergus J; Olson, Janet E; Vachon, Celine M; Giles, Graham G; Severi, Gianluca; Baglietto, Laura; Offit, Kenneth; John, Esther M; Miron, Alexander; Andrulis, Irene L; Knight, Julia A; Glendon, Gord; Mulligan, Anna Marie; Chanock, Stephen J; Lissowska, Jolanta; Liu, Jianjun; Cox, Angela; Cramp, Helen; Connley, Dan; Balasubramanian, Sabapathy; Dunning, Alison M; Shah, Mitul; Trentham-Dietz, Amy; Newcomb, Polly; Titus, Linda; Egan, Kathleen; Cahoon, Elizabeth K; Rajaraman, Preetha; Sigurdson, Alice J; Doody, Michele M; Guénel, Pascal; Pharoah, Paul D P; Schmidt, Marjanka K; Hall, Per; Easton, Doug F; Garcia-Closas, Montserrat; Milne, Roger L; Chang-Claude, Jenny

2013-03-27

201

Passive microwave detection of snowmelt and runoff  

NASA Astrophysics Data System (ADS)

Snow melt provides the dominant hydrologic signal for many watersheds across the globe. In developing countries and very remote regions, snow data are rarely available and assessing a snowpack's volume of water can be especially difficult. Remotely sensed passive microwave data offer the capability to monitor snowpack and snowmelt runoff in regions of limited data. Abrupt transitions in the SSM/I and AMSR-E passive microwave SWE estimates can indicate when the dry snowpack becomes wet and signify the onset of melt or rain-on-snow events. These transitions were analyzed with available discharge data to determine the utility in hydrological predictions in a large watershed in central Afghanistan and one of similar size in the United States. A correlation was found between abrupt decreases in SWE and discharge increases following rain events. The value for flood flow predictions is discussed.

Vuyovich, C.; Jacobs, J. M.

2011-12-01

202

Expansion of passive safety function  

SciTech Connect

Expansion of the use of passive safety functions is proposed. Two notions are presented. One is that, in the design of passive safety nuclear reactors where aversion of active components is stressed, some active components are purposely introduced, by which a system is built in such a way that it behaves in an apparently passive manner. The second notion is that, instead of using a passive safety function alone, a passive safety function is combined with some active components, relating the passivity in the safety function with enhanced controllability in normal operation. The nondormant system which the authors propose is one example of the first notion. This is a system in which a standby safety system is a portion of the normal operation system. An interpretation of the nondormant system via synergetics is made. As an example of the second notion, a PIUS density lock aided with active components is proposed and is discussed.

Inai, Nobuhiko; Nei, Hiromichi; Kumada, Toshiaki

1995-07-01

203

Passivation layers for reduced total dose effects and ELDRS in linear bipolar devices.  

SciTech Connect

It is shown that final chip passivation layers can have a significant impact on total dose hardness. A number of final chip passivation layers are evaluated to identify films that mitigate enhanced low-dose-rate sensitivity (ELDRS) in National Semiconductor Corporation's linear bipolar technologies. It is shown that devices fabricated with either a low temperature oxide or a tetraethyl ortho silicate passivation do not exhibit significant ELDRS effects up to 100 krad(SiO{sub 2}). Passivation studies on CMOS SRAMs suggest that it is unlikely that the passivation layers (or processing tools) are acting as a new source of hydrogen, which could drift or diffuse into the oxide and increase ELDRS sensitivity. Instead, it is possible that the passivation layers affect the mechanical stress in the oxide, which may affect oxide trap properties and possibly the release and mobility of hydrogen. Correlations between mechanical stress induced by the passivation layers and radiation degradation are discussed.

Dodd, Paul Emerson; Riewe, Leonard Charles; Pease, Ronald L.; Shaneyfelt, Marty Ray; Gupta, Sunny; Maher, Michael C.; Schwank, James Ralph

2003-07-01

204

Surface passivation optimization using DIRECT  

SciTech Connect

We describe a systematic and efficient method of determining pseudo-atom positions and potentials for use in nanostructure calculations based on bulk empirical pseudopotentials (EPMs). Given a bulk EPM for binary semiconductor X, we produce parameters for pseudo-atoms necessary to passivate a nanostructure of X in preparation for quantum mechanical electronic structure calculations. These passivants are based on the quality of the wave functions of a set of small test structures that include the passivants. Our method is based on the global optimization method DIRECT. It enables and/or streamlines surface passivation for empirical pseudopotential calculations.

Graf, Peter A. [National Renewable Energy Laboratory (NREL), Golden, CO 80401 (United States)]. E-mail: peter_graf@nrel.gov; Kim, Kwiseon [National Renewable Energy Laboratory (NREL), Golden, CO 80401 (United States); Jones, Wesley B. [National Renewable Energy Laboratory (NREL), Golden, CO 80401 (United States); Wang, Lin-Wang [Computational Research Division, Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720 (United States)

2007-06-10

205

Passive-solar construction handbook  

NASA Astrophysics Data System (ADS)

An identification and explanation of pertinent considerations in the construction of passively solar heated buildings are presented. Toward that end, the handbook discusses solar design principles, site planning and access, system components, construction details, financial considerations and other items which are essential considerations in passive solar design. The handbook was designed for a multitude of uses: as an instructional tool in workshops and seminars; as a compendium of passive solar design elements; and, as a reference guide to building trade professionals entering passive solar construction.

1981-09-01

206

Genetic risk for violent behavior and environmental exposure to disadvantage and violent crime: the case for gene-environment interaction.  

PubMed

Despite mounds of evidence to suggest that neighborhood structural factors predict violent behavior, almost no attention has been given to how these influences work synergistically (i.e., interact) with an individual's genetic propensity toward violent behavior. Indeed, two streams of research have, heretofore, flowed independently of one another. On one hand, criminologists have underscored the importance of neighborhood context in the etiology of violence. On the other hand, behavioral geneticists have argued that individual-level genetic propensities are important for understanding violence. The current study seeks to integrate these two compatible frameworks by exploring gene-environment interactions (GxE). Two GxEs were examined and supported by the data (i.e., the National Longitudinal Study of Adolescent Health). Using a scale of genetic risk based on three dopamine genes, the analysis revealed that genetic risk had a greater influence on violent behavior when the individual was also exposed to neighborhood disadvantage or when the individual was exposed to higher violent crime rates. The relevance of these findings for criminological theorizing was considered. PMID:22829212

Barnes, J C; Jacobs, Bruce A

2012-07-24

207

Selection of genes for gene-environment interaction studies: a candidate pathway-based strategy using asthma as an example  

PubMed Central

Background The identification of gene by environment (GxE) interactions has emerged as a challenging but essential task to fully understand the complex mechanism underlying multifactorial diseases. Until now, GxE interactions have been investigated by candidate approaches examining a small number of genes, or agnostically at the genome wide level. Presentation of the hypothesis In this paper, we propose a gene selection strategy for investigation of gene-environment interactions. This strategy integrates the information on biological processes shared by genes, the canonical pathways to which they belong and the biological knowledge related to the environment in the gene selection process. It relies on both bioinformatics resources and biological expertise. Testing the hypothesis We illustrate our strategy by considering asthma, tobacco smoke as the environmental exposure, and genes sharing the same biological function of “response to oxidative stress”. Our filtering strategy leads to a list of 28 pathways involving 182 genes for further GxE investigation. Implications of the hypothesis By integrating the environment into the gene selection process, we expect that our strategy will improve the ability to identify the joint effects and interactions of environmental and genetic factors in disease.

2013-01-01

208

Gene-environment interplay in Drosophila melanogaster: chronic food deprivation in early life affects adult exploratory and fitness traits.  

PubMed

Early life adversity has known impacts on adult health and behavior, yet little is known about the gene-environment interactions (GEIs) that underlie these consequences. We used the fruit fly Drosophila melanogaster to show that chronic early nutritional adversity interacts with rover and sitter allelic variants of foraging (for) to affect adult exploratory behavior, a phenotype that is critical for foraging, and reproductive fitness. Chronic nutritional adversity during adulthood did not affect rover or sitter adult exploratory behavior; however, early nutritional adversity in the larval period increased sitter but not rover adult exploratory behavior. Increasing for gene expression in the mushroom bodies, an important center of integration in the fly brain, changed the amount of exploratory behavior exhibited by sitter adults when they did not experience early nutritional adversity but had no effect in sitters that experienced early nutritional adversity. Manipulation of the larval nutritional environment also affected adult reproductive output of sitters but not rovers, indicating GEIs on fitness itself. The natural for variants are an excellent model to examine how GEIs underlie the biological embedding of early experience. PMID:23045644

Burns, James Geoffrey; Svetec, Nicolas; Rowe, Locke; Mery, Frederic; Dolan, Michael J; Boyce, W Thomas; Sokolowski, Marla B

2012-10-08

209

Gene-environment interactions across development: Exploring DRD2 genotype and prenatal smoking effects on self-regulation  

PubMed Central

Genetic factors dynamically interact with both pre- and postnatal environmental influences to shape development. Considerable attention has been devoted to gene-environment interactions (GxE) on important outcomes (Caspi & Moffitt, 2006). It is also important to consider the possibility that these GxE effects may vary across development, particularly for constructs like self-regulation that emerge slowly, depend on brain regions that change qualitatively in different developmental periods, and thus may be manifested differently. To illustrate one approach to explore such developmental patterns, the relation between variation in the TaqIA polymorphism, related to D2 dopamine receptor expression and availability, and prenatal exposure to tobacco, was examined in two exploratory studies. First, in 4-week-old neonates, genotype-exposure interactions were observed for attention and irritable reactivity, but not for stress dysregulation. Second, in preschool children, genotype was related to Trails-P task performance on conditions requiring executive control, and children with both the A1+ genotype and a history of prenatal tobacco exposure displayed disproportionately poor performance. Despite study limitations, these results illustrate the importance of examining the interplay between genetic and prenatal environmental factors across development.

Wiebe, Sandra A.; Espy, Kimberly Andrews; Stopp, Christian; Respass, Jennifer; Stewart, Peter; Jameson, Travis R.; Gilbert, David G.; Huggenvik, Jodi I.

2010-01-01

210

Chronic and Acute Stress, Gender, and Serotonin Transporter Gene-Environment Interactions Predicting Depression Symptoms in Youth  

PubMed Central

Background Many recent studies of serotonin transporter gene by environment effects predicting depression have used stress assessments with undefined or poor psychometric methods, possibly contributing to wide variation in findings. The present study attempted to distinguish between effects of acute and chronic stress to predict depressive symptoms at age 20 among 346 youth varying in polymorphisms of the 5HTT gene who had been assessed at ages 15 and 20. Methods Interview measures assessed major acute life events between 15 and 19, and multiple interviews and questionnaires with youths and their parents at youth age 15 provided an index of chronic family stress. Lg alleles were reclassified as S. Results Chronic family stress at age 15 predicted higher depression scores at 20 among those with one or two S alleles, and the effects of genetic moderation were significant only for females. Gene-environment interactions with acute stress were nonsignificant. Conclusions Careful measurement and separation of the effects of chronic and acute stress, and gender, are encouraged in the study of mechanisms of the stress-depression association.

Hammen, Constance; Brennan, Patricia A.; Keenan-Miller, Danielle; Hazel, Nicholas A.; Najman, Jake M.

2010-01-01

211

[Determination of the tensile strength of superficial passive implant materials].  

PubMed

The crack strength of passivating surface materials or passive layers on electroconductive substrates is determined by the electronic detection of redox reactions at the electrolyte/sample interface. A sudden increase in corrosion current under mechanical tensile loading or bending moments indicates generation or propagation of macro- and micro-cracks in the passivating layer, and exposure of the substrate. A subsequent decrease in the current indicates repassivation. Titanium oxide passivating layers generated by oxygen diffusion hardening (ODH) on titanium show crack formation at a tensile load on the substrate of more than 230 MPa. Repassivating sandwich layers of tantalum and tantalum oxide on steel substrates (AISI 31 6L) generate micro-cracks at more than 300 MPa. The crack formation of the oxide surface materials correlates with the onset of plastic deformation of the substrate. PMID:12585048

Macionczyk, F; Thull, R

2002-12-01

212

Fundamental studies of passivity and passivity breakdown. Final report.  

National Technical Information Service (NTIS)

This report summarizes the findings of our fundamental research program on passivity and passivity breakdown. During the past three and one half years in this program (including the three year incrementally-funded grant prior to the present grant), we dev...

D. D. Macdonald M. Urquidi-Macdonald H. Song S. Biaggio-Rocha P. Searson

1991-01-01

213

Commentary on "Capturing the Evasive Passive"  

ERIC Educational Resources Information Center

|Passives has been the focus of much research in language acquisition since the 1970s. It has been clear from this research that young children seldom produce passives spontaneously, particularly "long" or "full" passives with a by-phrase; and they usually perform poorly on experimental tests of the comprehension of passives, especially passives

Lillo-Martin, Diane; Snyder, William

2009-01-01

214

Materials for passively safe reactors  

Microsoft Academic Search

Future nuclear power capacity will be based on reactor designs that include passive safety features if recent progress in advanced nuclear power developments is realized. There is a high potential for nuclear systems that are smaller and easier to operate than the current generation of reactors, especially when passive or intrinsic characteristics are applied to provide inherent stability of the

Simnad

1993-01-01

215

Learning the Passive in Zulu.  

ERIC Educational Resources Information Center

|A study of the late acquisition of the passive in Zulu used data from transcripts of naturalistic speech gathered in a longitudinal study of several children's speech development between 1.10 and 3.6 years of age. It was hypothesized that the productivity of the passive construction in Zulu is a factor facilitating acquisition. A range of…

Suzman, Susan M.

1985-01-01

216

Temperature initiated passive cooling system  

Microsoft Academic Search

A passive cooling system for cooling an enclosure only when the enclosure temperature exceeds a maximum standby temperature comprises a passive heat transfer loop containing heat transfer fluid having a particular thermodynamic critical point temperature just above the maximum standby temperature. An upper portion of the heat transfer loop is insulated to prevent two phase operation below the maximum standby

Charles W

1994-01-01

217

Passive solar heating and analysis  

SciTech Connect

Passive solar heating experience and analysis techniques are reviewed with emphasis on annual auxiliary heat requirement. The role of analysis in the design of passive solar buildings is discussed. Selected results for existing systems are presented for locations in Saudi Arabia and climatically similar locations in the US. Advanced systems in the research stage are described.

Jones, R.W.

1984-01-01

218

Passive vapor extraction feasibility study.  

National Technical Information Service (NTIS)

Demonstration of a passive vapor extraction remediation system is planned for sites in the 200 West Area used in the past for the disposal of waste liquids containing carbon tetrachloride. The passive vapor extraction units will consist of a 4-in.-diamete...

V. J. Rohay

1994-01-01

219

Passive solar: subdivisions, windows, underground  

Microsoft Academic Search

A collection of papers illustrating the use of passive solar design are presented. Solar design is traced from over a century ago to the present. Discussed are design considerations for the mass market, products which enhance the application of passive solar techniques, market and financing problems. Window design is discussed in terms of glass, air infiltration, air movement, thermal transfer

H. Wade; J. Cook; K. Labs; S. Selkowitz

1983-01-01

220

Passive containment cooling system  

DOEpatents

A passive containment cooling system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel and is vented to the drywell. An isolation pool is disposed above the GDCS pool and includes an isolation condenser therein. The condenser has an inlet line disposed in flow communication with the drywell for receiving the non-condensable gas along with any steam released therein following a loss-of-coolant accident (LOCA). The condenser also has an outlet line disposed in flow communication with the drywell for returning to the drywell both liquid condensate produced upon cooling of the steam and the non-condensable gas for reducing pressure within the containment vessel following the LOCA. 1 figure.

Billig, P.F.; Cooke, F.E.; Fitch, J.R.

1994-01-25

221

Stain length passive dosimeters  

SciTech Connect

Passive dosimeters with instant readout capability have been devised by combining the principles of a gas indicator tube with membrane control of mass transfer. The membrane controls the diffusion of the gas or vapour to the reagent-impregnated support where it reacts to produce a stain. Results with H/sub 2/S and benzene monitors demonstrate that time-weighted average concentration of ambient gas or vapour can be measured accurately and precisely by following the movement of the coloured stain in the specially prepared and calibrated indicator tube. The 95% confidence interval of such measurements at the ThV is +/-20% for H/sub 2/S and +/-15% for benzene, well within NI0SH limits of acceptability.

Sefton, M.V.

1982-11-01

222

Stain length passive dosimeters  

SciTech Connect

Passive dosimeters with instant readout capability have been devised by combining the principles of a gas indicator tube with membrane control of mass transfer. The membrane controls the diffusion of the gas or vapor to the reagent impregnanted support where it reacts to produce a stain. Results with H/sub 2/S and benzene monitors demonstrated that time weighted average concentration of ambient gas or vapor can be measured accurately and precisely by following the movement of the colored stain in the specially prepared and calibrated indicator tube. The 95% confidence interval of such measurements at the TLV (80 ppm-hrs) is +/- 20% for H/sub 2/S and +/- 15% for benzene, well within NIOSH limits of acceptability.

Sefton, M.V.; Kostas, A.V.; Lombardi, C.

1982-11-01

223

Small passive chemical detector  

SciTech Connect

A novel technique has been developed for the detection of organic compounds in the environment. These detectors are passive'' in the sense that they do not contain any electronic or mechanical instrumentation. A visual color change of the devices after exposure to the target compounds of interest allows a quick identification and quantitative determination of the targets. The detection mechanism is based on colorimetry and combines two molecular biology techniques, Enzyme Multiplied Immunoassay Technique (EMIT) and Ouchterlony Double Diffusion in Two Dimensions. Preliminary studies have shown that the presence of 2,4-dinitrophenol can be monitored by the formation of the blue colored complexes as a result of the reaction between an enzyme (alkaline phosphatase) and a substrate (5-bromo-4-chloro-3-indolyl phosphate).

Hong, K.C.

1992-03-26

224

Affordable passive solar homes  

SciTech Connect

This book presents plans and designs for residential solar heating or cooling systems that use no external mechanical power to move collected solar heat. The proposed designs range in size from 300 to 1,600 square feet and are based on minimal construction time, minimal materials and labor, optimized utilization, and adaptability of space. Topics considered include home ownership economics, site selection and microclimate, codes and regulations, cross ventilation and inductive airflow, basic building materials, the use of waste or salvageable materials, construction procedures, interiors, daylighting, control over noise, indoor air quality, compact homes, midsized homes, multiple homes, ultracompact homes, and survival homes. The passive solar home plans presented are principally designed for the large temperate and cold-climate zones of the continental United States.

Vrowther, R.L.

1984-01-01

225

Passive tamper-indicating secure container.  

National Technical Information Service (NTIS)

This paper describes a passive tamper-indicating secure container that has been designed to demonstrate concepts, features, and materials that can be used in passive container applications. (In a passive security system, physical phenomena provide visual ...

J. C. Bartberger

1993-01-01

226

Gene-environment interaction in externalizing problems among adolescents: evidence from the Pelotas 1993 Birth Cohort Study  

PubMed Central

Background The study of gene–environment interactions (G × E) is one of the most promising strategies to uncover the origins of mental disorders. Replication of initial findings, however, is essential because there is a strong possibility of publication bias in the literature. In addition, there is a scarcity of research on the topic originated from low- and middle-income countries (LMIC). The aim of this study was to replicate G × E hypotheses for externalizing problems among adolescents in a middle-income country. Methods As part of the Pelotas 1993 Birth Cohort Study, 5,249 children were enrolled at birth and followed up to the age of 15 years, with an 85.7% retention rate. We sought an interaction between the homozygosity of the 10-repeat allele at the dopamine transporter (DAT1) gene and prenatal maternal smoking in the development of hyperactivity problems during adolescence assessed by the Strengths and Difficulties Questionnaire. We also tested for an interaction between the uVNTR polymorphism at the monoamine oxidase A (MAOA) and the experience of childhood maltreatment in the occurrence of conduct problems among adolescent boys. Results Although there was a clear association between prenatal maternal smoking and hyperactivity scores in adolescence (p < 0.001), no main genetic or interaction effects for the DAT1 gene were detected. Similarly, childhood maltreatment showed to be associated with conduct problems among boys (p < 0.001), with no observable main genetic or interaction effects for the MAOA gene. Conclusions In the largest mental health G × E study performed in a LMIC to date, we did not replicate previous positive findings from the literature. Despite the presence of main environmental effects, there was no evidence of effect modification by genotype status. Additional replication efforts to measure G × E are needed to better understand the origins of mental health and illness, especially in LMIC.

Kieling, Christian; Hutz, Mara H; Genro, Julia P; Polanczyk, Guilherme V; Anselmi, Luciana; Camey, Suzi; Hallal, Pedro C; Barros, Fernando C; Victora, Cesar G; Menezes, Ana M B; Rohde, Luis Augusto

2013-01-01

227

A study of gene-environment interaction on the gene for angiotensin converting enzyme: a combined functional and population based approach  

Microsoft Academic Search

INTRODUCTION: Studies on the role of the insertion\\/deletion (I\\/D) polymorphism of the gene coding for angiotensin converting enzyme (ACE) in atherosclerosis have been inconsistent. In a meta-analysis, we recently showed that this relationship is stronger in high risk populations. In this paper, we used a combined functional and population based approach to investigate the gene-environment interaction of the ACE I\\/D

F. A. Sayed-Tabatabaei; A. F. C. Schut; A. Hofman; A. M. Bertoli Avella; J. M. Vergeer; J. C. M. Witteman; Duijn van C. M

2004-01-01

228

Cytochrome P450 1B1, a new keystone in gene-environment interactions related to human head and neck cancer?  

Microsoft Academic Search

Alcohol consumption and tobacco smoking are major causes of head and neck cancers, and regional differences point to the importance of research into gene-environment interactions. Much interest has been focused on polymorphisms of CYP1A1 and of GSTM1 and GSTT1, but a number of studies have not demonstrated significant effects. This has mostly been ascribed to small sample sizes. In general,

Ricarda Thier; Thomas Brüning; Peter H. Roos; Hermann M. Bolt

2002-01-01

229

Passive thermosiphon solar collector  

SciTech Connect

A passive thermosiphon solar collector was designed, built, installed and tested under this grant. The basic premise was to design a simple system that was economical to build and easy to install as a retrofit to many similar homes in the local community. The module is comprised of a 2X4 frame with a sandwiched insert consisting of a flat black painted aluminum absorber panel and a fiberglass reinforced plastic glazing. This insert is completely sealed from the environment with neoprene seals and rubber silicone sealant. The modules are enclosed in an overall framework of 2X8 material bolted to a concrete reinforced footing and attached to the residence at the top. This framework results in an air chamber behind the absorber panel where the air from the basement enters the chamber at the bottom and exits at the top of the chamber into the house. The air chamber is completely insulated with 5/8 inch polyisocyanurate foil covered foam board. Fabrication is detailed in the Design and Construction section and supplemented with the photo series submitted with the Second Quarter report. The test results indicate this modular concept is a viable solution to conserving our national resources and reducing heating expenses. In this specific experiment, the use of solar energy provided a thirty-five percent reduction in natural gas consumption for this home.

Sullivan, J.W.

1984-01-01

230

Polymeric passive laser shutters  

NASA Astrophysics Data System (ADS)

Passive laser shutters are designed to control laser pulse duration by the regulation of the Q-factor through the use of substances which change in transparency upon exposure to light. The present paper outlines the development of such a shutter composed of a radiation-resistant modified polymethyl methacrylic matrix which may be filled with different clear dyes. Experiments performed using a nickel dithiobenzyl complex as the dye are presented which show the optical density of the dye in the clear state to be proportional to the initial optical density of the shutter, and the ratio of these optical densities to depend on the purity of the materials and the extent of decay of the dye during polymerization. The feasibility of the polymer shutter in a small laser was demonstrated in experiments with a garnet laser, where no degradation was observed after 100,000 pulses, a neodymium glass laser operating for over 10,000 pulses, and a ruby laser. Potential applications of the modified polymethyl methacrylate material in other laser system components are also noted.

Gromov, D. A.; Diumaev, K. M.; Manenkov, A. A.; Masliukov, A. P.; Matiushin, G. A.; Nechitailo, V. S.; Prokhorov, A. M.

1982-10-01

231

Passive solar heating system  

NASA Astrophysics Data System (ADS)

The Toas State Office Building is a single-story office building in New Mexico which incorporates passive collection and storage of solar energy along with natural lighting for general illumination. The building is oriented to take advantage of early morning sunlight and is designed to supply 70% of the heating load by solar heat. The site is equipped with clerestory windows, totaling 2695 square feet, 296 square feet of south facing windows, and east and west window scoops totaling 218 square feet. The collected solar energy is stored in 14,080 gallons of water contained in drums located in the clerestory area, as well as in the masonry construction mass. Auxiliary heat is provided via electric strips in the supply ducts. Movable, insulated shutters are provided to reduce the loss from the clerestory window area at night. The project is described with pictures and diagrams of the final installation provided. An updated performance data report is included, and functional problems, general comments, maintenance and refurbishment recommendations are discussed.

Mingenbach, W.

1981-08-01

232

Passive blast pressure sensor  

DOEpatents

A passive blast pressure sensor for detecting blast overpressures of at least a predetermined minimum threshold pressure. The blast pressure sensor includes a piston-cylinder arrangement with one end of the piston having a detection surface exposed to a blast event monitored medium through one end of the cylinder and the other end of the piston having a striker surface positioned to impact a contact stress sensitive film that is positioned against a strike surface of a rigid body, such as a backing plate. The contact stress sensitive film is of a type which changes color in response to at least a predetermined minimum contact stress which is defined as a product of the predetermined minimum threshold pressure and an amplification factor of the piston. In this manner, a color change in the film arising from impact of the piston accelerated by a blast event provides visual indication that a blast overpressure encountered from the blast event was not less than the predetermined minimum threshold pressure.

King, Michael J.; Sanchez, Roberto J.; Moss, William C.

2013-03-19

233

Galaxy Zoo: passive red spirals  

NASA Astrophysics Data System (ADS)

We study the spectroscopic properties and environments of red (or passive) spiral galaxies found by the Galaxy Zoo project. By carefully selecting face-on disc-dominated spirals, we construct a sample of truly passive discs (i.e. they are not dust reddened spirals, nor are they dominated by old stellar populations in a bulge). As such, our red spirals represent an interesting set of possible transition objects between normal blue spiral galaxies and red early types, making up ~6 per cent of late-type spirals. We use optical images and spectra from Sloan Digital Sky Survey to investigate the physical processes which could have turned these objects red without disturbing their morphology. We find red spirals preferentially in intermediate density regimes. However, there are no obvious correlations between red spiral properties and environment suggesting that environment alone is not sufficient to determine whether a galaxy will become a red spiral. Red spirals are a very small fraction of all spirals at low masses (M* < 1010 Msolar), but are a significant fraction of the spiral population at large stellar masses showing that massive galaxies are red independent of morphology. We confirm that as expected, red spirals have older stellar populations and less recent star formation than the main spiral population. While the presence of spiral arms suggests that a major star formation could not have ceased a long ago (not more than a few Gyr), we show that these are also not recent post-starburst objects (having had no significant star formation in the last Gyr), so star formation must have ceased gradually. Intriguingly, red spirals are roughly four times as likely than the normal spiral population to host optically identified Seyfert/low-ionization nuclear emission region (LINER; at a given stellar mass and even accounting for low-luminosity lines hidden by star formation), with most of the difference coming from the objects with LINER-like emission. We also find a curiously large optical bar fraction in the red spirals (70 +/- 5 verses 27 +/- 5 per cent in blue spirals) suggesting that the cessation of star formation and bar instabilities in spirals are strongly correlated. We conclude by discussing the possible origins of these red spirals. We suggest that they may represent the very oldest spiral galaxies which have already used up their reserves of gas - probably aided by strangulation or starvation, and perhaps also by the effect of bar instabilities moving material around in the disc. We provide an online table listing our full sample of red spirals along with the normal/blue spirals used for comparison. This publication has been made possible by the participation of more than 160000 volunteers in the Galaxy Zoo project. Their contributions are individually acknowledged at http://www.galaxyzoo.org/Volunteers.aspx E-mail: karen.masters@port.ac.uk

Masters, Karen L.; Mosleh, Moein; Romer, A. Kathy; Nichol, Robert C.; Bamford, Steven P.; Schawinski, Kevin; Lintott, Chris J.; Andreescu, Dan; Campbell, Heather C.; Crowcroft, Ben; Doyle, Isabelle; Edmondson, Edward M.; Murray, Phil; Raddick, M. Jordan; Slosar, Anže; Szalay, Alexander S.; Vandenberg, Jan

2010-06-01

234

PS3-16: Access and Collaboration with the Kaiser Permanente Research Program on Genes, Environment, and Health (RPGEH)  

PubMed Central

Background/Aims The Kaiser Permanente Northern California (KPNC) Research Program on Genes, Environment, and Health (RPGEH) provides a research resource to support investigations of environmental and genetic factors in the development of a wide variety of conditions. While the resource is still evolving with new data collection, it consists of data from surveys and electronic medical records on over 400,000 adult members of KPNC; biospecimens collected and stored on ~200,000 of these individuals; and data from genome-wide and telomere-length assays on ~110,000 of those who have contributed biospecimens; and linkage of these members to environmental, area-level databases. Methods The RPGEH was developed in part with the understanding that it would be made available to the scientific community for appropriate studies. An Access and Collaborations Core has developed procedures for submission of applications for research studies, their review, and decisions on approval and support. Review of proposals by an Applications Review Committee follows a two-step process, with a pre-application to assess feasibility (e.g., adequate numbers of the phenotype: availability of appropriate data, given inclusion criteria) and a full application to assess appropriateness of the study in the RPGEH context. Scientific merit; alignment with RPGEH guiding principles, including ethical, legal, and social implications; consistency with informed consents; potential overlap with prior approvals; and collaboration with a researcher affiliated with the Division of Research are among the criteria for approval. As an alternative for select analyses, genomic and selected phenotypic data will be available in the NIH database of genotypes and phenotypes (dbGaP) for the substantial subset of RPGEH participants who have consented to dbGaP deposition. Results As of October 31, 2012, the RPGEH has received 74 pre-applications and full applications for the use of its resources; only 6 pre-applications were not approved. In 2011–2012, 13 approved applications were funded by NIH and other agencies. Studies currently underway include genome-wide association studies of prostate cancer, bi-polar disorder, multiple sclerosis, and mammographic density. Conclusions Access to the unique and outstanding research resources of the RPGEH balances the mission of promoting research with the need to shepherd finite resources and safeguard member confidentiality.

Schaffer, Donna; Kushi, Lawrence; Henderson, Mary; Clancy, Heather; Somkin, Carol; Quesenberry, Charles; Jorgenson, Eric; Samelson, Allen; Whitmer, Rachel; Habel, Laurel; Barcellos, Lisa

2013-01-01

235

Passive IR SO2 Sensor.  

National Technical Information Service (NTIS)

A remote operating Passive Infrared SO2 Sensor was developed. A system of quantitative measurement for field operation was created with simplicity of operation and minimum of interference as objectives. The complexities of the radiative process limit accu...

J. M. Lepper

1967-01-01

236

Passivating metals on cracking catalysts  

Microsoft Academic Search

Metals such as nickel, vanadium and iron contaminating a cracking catalyst are passivated by contacting the cracking catalyst under elevated temperature conditions with antimony selenide, antimony sulfide, antimony sulfate, bismuth selenide, bismuth sulfide, or bismuth phosphate.

Mckay

1980-01-01

237

Passivating metals on cracking catalysts  

SciTech Connect

Metals such as nickel, vanadium and iron contaminating a cracking catalyst are passivated by contacting the cracking catalyst under elevated temperature conditions with antimony selenide, antimony sulfide, antimony sulfate, bismuth selenide, bismuth sulfide, or bismuth phosphate.

Mckay, D.L.

1980-01-15

238

Passive coherent location radar demonstration  

Microsoft Academic Search

This paper describes a passive coherent location (PCL) radar system developed by Dynetics, Inc. This system uses commercial FM broadcast signals for the radar waveform. This paper presents a technical description of the system and performance data.

C. L. Zoeller; M. J. Moody

2002-01-01

239

Psychoacoustics and Passive Sonar Detection.  

National Technical Information Service (NTIS)

A review is made of the statistical theory of signal detection, followed by application of signal detection theory to psychoacoustics. The differences between relatively simple laboratory tests and the complex problems of passive sonar operating in the re...

J. M. Stallard C. B. Leslie

1974-01-01

240

Active/Passive Optical Hydrography.  

National Technical Information Service (NTIS)

The Airborne Bathymetric Survey (ABS) concept was adopted by the Defense Mapping Agency and the Navy in 1985. The ABS system combines two independent sensors, an active lidar and a passive multispectral scanner using GPS satellite data for positioning, in...

M. C. Harris M. T. Kalcic S. C. Lingsch S. P. Haimbach

1990-01-01

241

Passive Nosetip Technology (PANT) Program.  

National Technical Information Service (NTIS)

A summary of the analytical and experimental activities performed on the Passive Nosetip Technology (PANT) program is given. The various test programs are identified and key test results are described. Analysis results in the areas of surface roughness ef...

M. R. Wool

1975-01-01

242

Passive and active closures by constraining mechanisms  

Microsoft Academic Search

This paper provides a unified theoretical framework for grasping and manipulation by robotic grippers and hands as well as for fixing works by fixtures and vises. The concept of passive closure and active closure for general constraining mechanisms is introduced. Passive closure is further classified into passive form closure and passive force closure. Conditions for these closures to hold are

Tsuneo Yoshikawa

1996-01-01

243

Synthetic passive margin stratigraphy  

Microsoft Academic Search

Synthetic stratigraphic cross sections are derived mathematically for a variety of simple conditions. The variables considered in the mathematical model include variations in sea level, rate of tectonic subsidence, rate of sedimentation, and rate of erosion. Derived stratigraphic relationships include unconformities, correlative conformities and disconformities, coastal onlap, coastal toplap, erosional truncation, pinch-out, and sigmoidal progradational clinoforms. An important conclusion is

D. L. Turcotte; P. M. Kenyon

1984-01-01

244

Arterial stiffness, pressure and flow pulsatility and brain structure and function: the Age, Gene/Environment Susceptibility - Reykjavik Study  

PubMed Central

Aortic stiffness increases with age and vascular risk factor exposure and is associated with increased risk for structural and functional abnormalities in the brain. High ambient flow and low impedance are thought to sensitize the cerebral microcirculation to harmful effects of excessive pressure and flow pulsatility. However, haemodynamic mechanisms contributing to structural brain lesions and cognitive impairment in the presence of high aortic stiffness remain unclear. We hypothesized that disproportionate stiffening of the proximal aorta as compared with the carotid arteries reduces wave reflection at this important interface and thereby facilitates transmission of excessive pulsatile energy into the cerebral microcirculation, leading to microvascular damage and impaired function. To assess this hypothesis, we evaluated carotid pressure and flow, carotid–femoral pulse wave velocity, brain magnetic resonance images and cognitive scores in participants in the community-based Age, Gene/Environment Susceptibility – Reykjavik study who had no history of stroke, transient ischaemic attack or dementia (n = 668, 378 females, 69–93 years of age). Aortic characteristic impedance was assessed in a random subset (n = 422) and the reflection coefficient at the aorta–carotid interface was computed. Carotid flow pulsatility index was negatively related to the aorta–carotid reflection coefficient (R = ?0.66, P<0.001). Carotid pulse pressure, pulsatility index and carotid–femoral pulse wave velocity were each associated with increased risk for silent subcortical infarcts (hazard ratios of 1.62–1.71 per standard deviation, P<0.002). Carotid–femoral pulse wave velocity was associated with higher white matter hyperintensity volume (0.108 ± 0.045 SD/SD, P = 0.018). Pulsatility index was associated with lower whole brain (?0.127 ± 0.037 SD/SD, P<0.001), grey matter (?0.079 ± 0.038 SD/SD, P = 0.038) and white matter (?0.128 ± 0.039 SD/SD, P<0.001) volumes. Carotid–femoral pulse wave velocity (?0.095 ± 0.043 SD/SD, P = 0.028) and carotid pulse pressure (?0.114 ± 0.045 SD/SD, P = 0.013) were associated with lower memory scores. Pulsatility index was associated with lower memory scores (?0.165 ± 0.039 SD/SD, P<0.001), slower processing speed (?0.118 ± 0.033 SD/SD, P<0.001) and worse performance on tests assessing executive function (?0.155 ± 0.041 SD/SD, P<0.001). When magnetic resonance imaging measures (grey and white matter volumes, white matter hyperintensity volumes and prevalent subcortical infarcts) were included in cognitive models, haemodynamic associations were attenuated or no longer significant, consistent with the hypothesis that increased aortic stiffness and excessive flow pulsatility damage the microcirculation, leading to quantifiable tissue damage and reduced cognitive performance. Marked stiffening of the aorta is associated with reduced wave reflection at the interface between carotid and aorta, transmission of excessive flow pulsatility into the brain, microvascular structural brain damage and lower scores in various cognitive domains.

van Buchem, Mark A.; Sigurdsson, Sigurdur; Gotal, John D.; Jonsdottir, Maria K.; Kjartansson, Olafur; Garcia, Melissa; Aspelund, Thor; Harris, Tamara B.; Gudnason, Vilmundur; Launer, Lenore J.

2011-01-01

245

Passive film structure of supersaturated Al-Mo alloys  

SciTech Connect

This paper reports that reflection-extended x-ray absorption fine-structure spectroscopy has been used to probe the local atomic structure of the passive film of supersaturated Al-Mo alloys polarized in KCl. These alloys (with 7-11 atom percent Mo) exhibit resistance to localized attack with an increase in the pitting potential of {approximately} 600 mV relative to pure aluminum. Measurements show that the structure of the Al-Mo passive films resembles that of {alpha}-Al{sub 2}O{sub 3}/AlOOH, whereas an oxide film grown on pure Al in tartaric acid, which does not possess enhanced passivity, is more like {gamma}-Al{sub 2}O{sub 3}/AlOOH. Complementary x-ray photoelectron spectroscopy measurements indicate the Al-Mo passive film composition to be near that of AlOOH and the tartaric-acid film to be Al{sub 2}O{sub 3}. Because corundum ({Alpha}-Al{sub 2}O{sub 3}) and diaspore ({Alpha}-AlOOH), which contain only octahedrally coordinated Al atoms, are very stable and inert while {gamma}-Al{sub 2}O{sub 3}, which contains both octahedral and tetrahedral sites, is reactive, the change in structure of the passive film suggest that improved passivity may be correlated with a reduction in the density of tetrahedrally coordinated atoms. This structural change likely results from the incorporation of oxidized Mo into the passive film; only as this Mo is hydrated with a presumed change in local structure does the alloy pit.

Davis, G.D. (Martin Marietta Lab., Baltimore, MD (US)); Moshier, W.C. (Martin Marietta Space Systems, Denver, CO (US)); Long, G.G.; Black, D.R. (National Inst. for Standards and Technology, Gaithersburg, MD (US))

1991-11-01

246

Passive avoidance in syndromes of disinhibition: psychopathy and extraversion.  

PubMed

According to the physiological animal model proposed by Gorenstein and Newman (1980; see also Newman, Gorenstein, & Kelsey, 1983), psychopaths and extraverts may be characterized by a common psychological diathesis related to behavioral inhibition (see also Fowles, 1980; Gray, 1982). One aspect of this diathesis involves deficient passive avoidance learning, which has been central to explanations of "unsocialized" (e.g., Trasler, 1978) and antisocial behavior (e.g., Hare, 1970). Results from three experiments supported our prediction that psychopaths and extraverts would exhibit deficient passive avoidance relative to nonpsychopaths and introverts, respectively. In addition, the passive avoidance deficit was particularly evident in tasks that required subjects to inhibit a rewarded response in order to avoid punishment. The latter finding may be important for explaining the inconsistent results regarding passive avoidance learning in psychopaths (e.g., Chesno & Kilmann, 1975; Schmauk, 1970). Discussion of the results focuses on the importance of reward in mediating the passive avoidance deficit of "disinhibited" individuals and on the existence of an indirect relationship between psychopathy and extraversion: one that is consistent with the observed experimental parallels as well as with the more ambiguous evidence regarding a direct correlation between measures of the two syndromes. PMID:3998992

Newman, J P; Widom, C S; Nathan, S

1985-05-01

247

Surface passivation of Gallium Arsenide  

NASA Astrophysics Data System (ADS)

The surface passivation of Si doped (100) n-type gallium arsenide (GaAs) by chemical treatment with phosphoric acid (H3P04), phosphorus trichloride (PCl3), and sodium sulfide (Na2S.9H2O) was investigated using room temperature photoluminescence (PL) and a capacitance-voltage (C-V) and current-voltage (I-V) profiler. After passivation, the 300K PL increased for all three treatments. Best results obtained showed improvements of 1.4, 3.5 and 5.3 times greater of PL efficiency for H3PO4, PCl3 and Na2S, respectively, over unpassivated samples that were only cleaned and etched. Samples that were cleaned, etched and washed with de-ionized 18 Mohm, 5 ppm O2 content water showed about the same PL increase as the H3PO4 passivation. Capacitance-voltage and I-V profile curves showed the removal of the surface oxide hysteresis with the PCl3 passivated samples; however, re-oxidation seems to take longer than normal and to be confined to the passivation layer.

Racicot, Robert J.

1988-04-01

248

Passive resonators for wireless passive sensor readout enhancement  

NASA Astrophysics Data System (ADS)

A scheme to enhance a wireless passive sensor's readout is presented. This alternative consists of the addition of a passive inductive-capacitive resonator placed between the sensor and readout antenna. A discrete model is proposed and used in simulations to study the effects of the resonator in the sensor-antenna interaction. A resonator was fabricated at 28 MHz to test the enhancement of the sensor's signal. Increases in the sensor's signal and the power transmitted to the sensor were always obtained for frequencies below 28 MHz. All experimental results were consistent with the simulation outcomes.

Sanz, Diego A.; Mitrosbaras, Costantino; Unigarro, Edgar A.; Segura-Quijano, Fredy

2013-09-01

249

Replication and Meta-analysis of the Gene-Environment Interaction between Body Mass Index and the Interleukin-6 Promoter Polymorphism with Higher Insulin Resistance  

PubMed Central

Objective Insulin resistance (IR) is a complex disorder caused by an interplay of both genetic and environmental factors. Recent studies identified a significant interaction between body mass index (BMI) and the rs1800795 polymorphism of the Interleukin-6 (IL-6) gene that influences both IR and onset of type 2 diabetes mellitus (T2DM) with obese individuals homozygous for the C allele demonstrating the highest level of IR and greatest risk for T2DM. Replication of a gene-environment interaction is important to confirm the validity of the initial finding and extends the generalizability of the results to other populations. Thus, the objective of this study was to replicate this gene-environment interaction on IR in a hypertensive population and perform a meta-analysis with prior published results. Material and Methods The replication analysis was performed using Caucasian individuals with hypertension (HTN) from the HyperPATH cohort (N=311), genotyped for rs1800795. Phenotype studies were conducted after participants consumed two diets: high sodium (HS) (200mmol/day) and low sodium (LS) (10mmol/day) for 7 days each. Measurements for plasma glucose, insulin, and IL-6 were obtained after 8 hours of fasting. IR was characterized by the homeostatic model assessment (HOMA-IR). Results In HyperPATH, BMI was a significant effect modifier of the relationship between rs1800795 and HOMA-IR; higher BMI was associated with higher HOMA-IR among homozygote CC individuals when compared to major allele G carriers (p=0.003). Further, the meta-analysis in 1028 individuals confirmed the result demonstrating the same significant interaction between rs1800795 and BMI on HOMA-IR (p=1.05×10?6). Conclusion This rare replication of a gene-environment interaction extends the generalizability of the results to HTN while highlighting this polymorphism as a marker of IR in obese individuals.

Underwood, Patricia C.; Chamarthi, Bindu; Williams, Jonathan S.; Sun, Bei; Vaidya, Anand; Raby, Benjamin A.; Lasky-Su, Jessica; Hopkins, Paul N.; Adler, Gail K.; Williams, Gordon H.

2012-01-01

250

Integral passive solar water heater performance  

SciTech Connect

Passive solar water heaters can be divided into two classes: systems in which the functions of heat collection and storage are separate (the thermosiphon flat plate systems), and systems with combined collection and storage - the integral passive solar water heater (IPSWH). IPSWH systems are much less widely known despite some inherent advantages, including simplicity, low cost, and resistance to freezing. The first solar water heaters widely used in the U.S were IPSWHs. They gradually fell out of favor because of night cooldown and tank corrosion. New materials and designs minimize these problems and promise to bring the IPSWH back into the forefront of solar activity. Described are recent IPSWH experiments evaluating new materials and designs. These are then correlated with work by other investigators to suggest the tremendous potential for IPSWH use around the world. The characteristics of IPSWHs make traditional solar system test procedures inadequate and a new test procedure for IPSWH system is proposed. The low cost of IPSWHs more than offsets their slightly lower performance and will make them the most cost-effective heater for many climates and uses.

Bainbridge, D.A.

1981-01-01

251

Passive-solar retrofit concepts  

NASA Astrophysics Data System (ADS)

Four retrofit passive solar designs for single family dwellings are presented. The first design, for a house in Minnesota, involves insulating wall cavities and the attic with blown cellulose, reduction of infiltration, and installation of insulating shades on all windows. The second, for a house in Michigan, combines weatherization, a sunspace with clerestory, and a thermosiphoning collector. The third, for a house in Missouri, involves the addition of a large sunspace with a passive solar hot water preheater for a hot tub. The fourth, for a house in Indiana, combines intensive weatherization with a two story sunspace and thermal chimney addition. All designs are thoroughly illustrated.

1981-09-01

252

Passive solar study. Existing passive solar contributions in buildings.  

National Technical Information Service (NTIS)

In November 1992 the Energy Technology Support Unit invited ECD to prepare a study with the objective of quantifying the passive solar contribution to the UK domestic and non-domestic building energy requirements at 1990 levels. This has been achieved by ...

S. Burton J. Maxwell

1993-01-01

253

Bayesian inference of gene-environment interaction from incomplete data: what happens when information on environment is disjoint from data on gene and disease?  

PubMed

Inference in gene-environment studies can sometimes exploit the assumption of mendelian randomization that genotype and environmental exposure are independent in the population under study. Moreover, in some such problems it is reasonable to assume that the disease risk for subjects without environmental exposure will not vary with genotype. When both assumptions can be invoked, we consider the prospects for inferring the dependence of disease risk on genotype and environmental exposure (and particularly the extent of any gene-environment interaction), without detailed data on environmental exposure. The data structure envisioned involves data on disease and genotype jointly, but only external information about the distribution of the environmental exposure in the population. This is relevant as for many environmental exposures individual-level measurements are costly and/or highly error-prone. Working in the setting where all relevant variables are binary, we examine the extent to which such data are informative about the interaction, via determination of the large-sample limit of the posterior distribution. The ideas are illustrated using data from a case-control study for bladder cancer involving smoking behaviour and the NAT2 genotype. PMID:21432881

Gustafson, Paul; Burstyn, Igor

2011-01-13

254

Gene-environment interaction between dopamine receptor D4 7-repeat polymorphism and early maternal sensitivity predicts inattention trajectories across middle childhood.  

PubMed

Evidence suggests that the 7-repeat variant of a 48 base pair variable number tandem repeat polymorphism in the dopamine receptor D4 (DRD4) gene may be associated with the development of attention problems. A parallel literature suggests that genes linked to dopaminergic functioning may be associated with differential sensitivity to context, such that the direction of the genetic effect is hypothesized to vary across environmental experience. Guided by these literatures, we used data from the NICHD Study of Early Child Care and Youth Development to consider (a) whether individual differences in children's inattention problems across middle childhood are predicted by gene-environment interactions between the DRD4 gene 7-repeat polymorphism and children's experiences of maternal sensitivity across infancy and early childhood and (b) the degree to which such interactions are consistent with the differential-sensitivity model. Largely consistent with the hypothesized model, gene-environment interactions indicated that, in the context of insensitive early maternal care, the DRD4 7-repeat polymorphism was associated with higher levels of inattention. Although somewhat less consistently, there was also evidence that, in the context of highly sensitive care, the 7-repeat polymorphism was associated with lower levels of inattention. Overall, the magnitude of the absolute genetic effect increased over time, as children's inattention trajectories diverged. PMID:23627945

Berry, Daniel; Deater-Deckard, Kirby; McCartney, Kathleen; Wang, Zhe; Petrill, Stephen A

2013-05-01

255

Surface Passivation of Gallium Arsenide.  

National Technical Information Service (NTIS)

The surface passivation of Si doped (100) n-type gallium arsenide (GaAs) by chemical treatment with phosphoric acid (H3P04), phosphorus trichloride (PCl3), and sodium sulfide (Na2S.9H2O) was investigated using room temperature photoluminescence (PL) and a...

R. J. Racicot

1988-01-01

256

MGA and passive neutron measurements.  

National Technical Information Service (NTIS)

MGA is a gamma-ray spectrum analysis program for determining relative plutonium isotopic abundances. The isotopic composition of a plutonium sample is needed to calculate (sup 240)Pu(sub eff) that is used to interpret passive neutron coincidence measureme...

W. D. Ruhter R. Gunnink S. Baumann S. Abeynaike J. Verplancke

1993-01-01

257

Passive energy in historical Tunisia  

Microsoft Academic Search

The Romans of 200 AD used a variety pf passive energy devices for climate control of underground housing in the ancient city of Bulla Regia, Tunisia. The preliminary results of a study of three such homes are reported and several of the climate control devices and the methods used to create an even level of natural daylighting in their underground

R. S. Cole; R. Kennedy

1980-01-01

258

Passive solar, country-style  

SciTech Connect

This article describes a 2170 ft{sup 2} (202 m{sup 2}) custom-designed passive solar home in rural Burlington, North Carolina. The architectural style elegantly combines pleasing aesthetics with practical attention to energy conservation. Included in the article are details of the construction, energy efficient materials and design, energy performance, cost performance.

Miller, B.

1996-07-01

259

Slow Modes in Passive Advection.  

National Technical Information Service (NTIS)

The anomalous scaling in the Kraichnan model of advection of the passive scalar by a random velocity field with non-smooth spatial behavior is traced down to the presence of slow resonance-type collective modes of the stochastic evolution of fluid traject...

D. Bernard K. Gawedzki A. Kupiainen

1997-01-01

260

Passive solar energy in buildings  

Microsoft Academic Search

Designing commercial, institutional and domestic buildings so that they reap the benefits of freely available solar energy, is explored fully. People have been orientating buildings to make use of sunlight since they first began to live in permanent dwellings. New techniques are now available for employing passive solar energy in the home. On a bigger scale, these and other techniques

1988-01-01

261

A Multiband Passive Radar Demonstrator  

Microsoft Academic Search

Passive radar systems that exploit signals from the plethora of RF emissions that exist in the external environment offer a number of advantages over conventional active radar system, including procurement and operational cost saving. Each emitter has its own characteristics, including waveforms, which dictate system performance. BAE Systems Advanced Technology Centre has designed and built a demonstrator system to act

Dale Gould; Robert Pollard; Carlos Sarno; Paul Tittensor

2006-01-01

262

PASSIVE DETECTION OF VEHICLE LOADING  

Microsoft Academic Search

The Digital Imaging and Remote Sensing Laboratory (DIRS) at the Rochester Institute of Technology, along with the Savannah River National Laboratory is investigating passive methods to quantify vehicle loading. The research described in this paper investigates multiple vehicle indicators including brake temperature, tire temperature, engine temperature, acceleration and deceleration rates, engine acoustics, suspension response, tire deformation and vibrational response. Our

2012-01-01

263

Passive maser development at NRL  

SciTech Connect

The application of passive hydrogen masers to satellites was investigated. The NRL maser is of compact design suitable for the space environment. It is based on a dielectrically loaded sapphire cavity and uses a computer optimized set of four shields. The servo design is a phase sensitive method which directly measures the phase dispersion of the interrogating signal as it passes through the cavity.

White, J.D.; Frank, A.; Folen, V.

1981-01-01

264

Correlation Algorithm: the Conceptual Framework.  

National Technical Information Service (NTIS)

The lack of a utilitarian solution to the frame-to-frame correlation problem poses insurmountable difficulties for the successful passive observation of a collection of co-moving, nearly co-located objects. This is exactly the task faced in a scenario wit...

L. G. Taff

1988-01-01

265

Mapping the Whole Internet with Passive Measurements.  

National Technical Information Service (NTIS)

This final technical report describes an effort to develop a comprehensive and accurate map of the Internet using passive measurements, diverse data sets and statistical learning methods. The effort passively collected a comprehensive set of Internet traf...

B. Maggs

2012-01-01

266

Passively walking five-link robot  

Microsoft Academic Search

In this article we investigate the dynamics of a five-link, passive bipedal robot. The passivity in this context stands for the ability of the robot to walk autonomously down an inclined surface without any external source of energy. Previous research efforts in passive walking were limited to four link models with knees or 2-link models without knees with a variety

Elena Borzova; Yildirim Hurmuzlu

2004-01-01

267

Radiometric linearity in passive FTIR spectrometry  

Microsoft Academic Search

Passive standoff FTIR spectrometry relies on the radiance differential between a background scene and a target vapor analyte. Unlike traditional FTIR approaches controlling radiance levels within a narrow range, the passive configuration often encounters a large variance in radiance levels. This places higher demands on the passive FTIR configuration for maintaining linearity. The present study assesses the radiometric linearity of

Robert T. Kroutil; Roger J. Combs; Robert B. Knapp

1999-01-01

268

User evaluation study of passive solar residences  

SciTech Connect

Speculation exists regarding the readiness of various passive techniques for commercialization and the market potential for residential applications. This paper discusses the preliminary findings of a market assessment study designed to document user experiences with passive solar energy. Owners and builders of passive solar homes were interviewed and asked to comment on personal experiences with their homes.

Towle, S.

1980-03-01

269

Phase-change products for passive homes  

SciTech Connect

The use of phase change materials (PCM) in passive solar energy applications is discussed. The performance of the passive phase change storage house designs compared with the annual heating loads for an identical house having no added thermal storage mass is discussed. The use of calcium chloride hexahydrate as the PCM in several passive solar applications is discussed.

Kohler, J.; Lewis, D.

1983-05-01

270

Treat mine water using passive methods  

Microsoft Academic Search

Passive treatment represents an alternative to conventional chemical treatment of coal mine drainage. When successful, passive systems require less investment, less maintenance and usually are less expensive than conventional chemical treatment systems. As a result, during the last seven years, more than 500 passive systems have been constructed in the United States to treat coal mine drainage. Some exist as

R. L. P. Kleinmann; R. S. Hedin

1993-01-01

271

Fundamental studies of passivity and passivity breakdown. Final report, [September 1993--September 1994  

SciTech Connect

Purpose is to understand the mechanisms for growth and breakdown of passive films on metal and alloy surfaces in aqueous medium; a secondary goal is to devise methods for predicting localized corrosion damage in industrial systems. Tasks currently being studied are: formation of bilayer structures in passive films on metals and alloys; passivity breakdown on solid vs. liquid gallium; roles of alloying elements in passivity breakdown; electrochemical impedance spectroscopy of passive films; electronic structure of passive oxide films; photoelectrochemical impedance spectroscopy of passive films; and kinetics of localized attack.

Macdonald, D.D.; Urquidi-Macdonald, M.

1994-02-21

272

Use of reference chemicals to determine passive uptake rates of common indoor air VOCs by collocation deployment of active and passive samplers.  

PubMed

Passive samplers have become more popular in their application in the measurement of airborne chemicals. For volatile organic compounds, the rate of a chemical's diffusivity is a determining factor in the quantity of the chemical being collected for a given passive sampler. While uptake rate of a chemical in the passive sampler can be determined either by collocation deployment of both active and passive samplers or use of controlled facilities such as environmental chambers, a new approach without a need for accurate active flow rate in the collocation experiment was demonstrated in this study. This approach uses chemicals of known uptake rates as references to calculate the actual flow rate of the active sampling in the collocation experiment. The active sampling rate in turn can be used in the determination of the uptake rates of all other chemicals present in the passive samplers. The advantage of such approach is the elimination of the errors in actual active sampling rate associated with low flow employed in the collocation experiment. Using this approach, passive uptake rates of more than 80 volatile organic compounds commonly present in indoor air were determined. These experimentally determined uptake rates correlate well with air diffusivity of the chemicals, indicating the regression equation describing such correlation might be useful in predicting the uptake rates of other volatile organic chemicals in indoor air based on their air diffusivity. PMID:21773627

Xian, Qiming; Feng, Yong-Lai; Chan, Cecilia C; Zhu, Jiping

2011-07-20

273

Active and realistic passive marijuana exposure tested by three immunoassays and GC/MS in urine  

SciTech Connect

Human urine samples obtained before and after active and passive exposure to marijuana were analyzed by immune kits (Roche, Amersham, and Syva) and gas chromatography/mass spectrometry (GC/MS). Seven of eight subjects were positive for the entire five-day test period with one immune kit. The latter correlated with GC/MS in 98% of the samples. Passive inhalation experiments under conditions likely to reflect realistic exposure resulted consistently in less than 10 ng/mL of cannabinoids. The 10-100-ng/mL cannabinoid concentration range essential for detection of occasional and moderate marijuana users is thus unaffected by realistic passive inhalation.

Mule, S.J.; Lomax, P.; Gross, S.J.

1988-05-01

274

Development of thermal performance criteria for residential passive solar buildings. Final report  

SciTech Connect

In support of the development of thermal performance criteria for residential passive solar buildings, thermal design characteristics and anticipated performance for 266 projects in the HUD Passive Residential Design Competition and the HUD Cycle 5 Demonstration Program were analyzed. A number of performance measures were examined, including net solar contribution, solar fraction, and auxiliary energy use. These and other design and climate-related parameters were statistically correlated using the DATAPLOT computer program and standard statistical analysis techniques.

Sabatiuk, P.A.; McCabe, M.

1980-10-01

275

A general approach to the development of passive/active sensor data fusion  

NASA Astrophysics Data System (ADS)

This paper addresses the multisensor track-to-track correlation and fusion problem in a surveillance environment. In particular, this paper considers a general approach to the development of a master track file based on track data from a co-located passive and an active sensor. Sensor report-to-track correlation and fusion algorithms are discussed.

Chaudhuri, S. P.

276

Anomalous Scaling in the N-Point Functions of Passive Scalar.  

National Technical Information Service (NTIS)

A recent analysis of the 4-point correlation function of the passive scalar advected by a time-decorrelated random flow is extended to the N-point case. It is shown that all stationary-state inertial-range correlations are dominated by homogeneous zero mo...

D. Bernard K. Gawedzki A. Kupiainen

1996-01-01

277

Passive sonar fusion for submarine C2 systems  

Microsoft Academic Search

The most important sensors for gathering target information onboard a submarine are passive sonars. Problems concerning fusion of these passive sonars are discussed. Three typical passive sonars-passive noise sonar, passive ranging sonar and acoustic pulse surveillance sonar-constitute a passive sonar system for data fusion. This paper is concerned mainly with problems of significance in system development, such as tactical application

Pailon Shar; X. Rong Li

2000-01-01

278

The suppression of immune system disorders by passive attrition.  

PubMed

Exposure to infectious diseases has an unexpected benefit of inhibiting autoimmune diseases and allergies. This is one of many fundamental fitness tradeoffs associated with immune system architecture. The immune system attacks pathogens, but also may (inappropriately) attack the host. Exposure to pathogens can suppress the deleterious response, at the price of illness and the decay of immunity to previous diseases. This "hygiene hypothesis" has been associated with several possible underlying biological mechanisms. This study focuses on physiological constraints that lead to competition for survival between immune system cell types. Competition maintains a relatively constant total number of cells within each niche. The constraint implies that adding cells conferring new immunity requires loss (passive attrition) of some cells conferring previous immunities. We consider passive attrition as a mechanism to prevent the initial proliferation of autoreactive cells, thus preventing autoimmune disease. We see that this protection is a general property of homeostatic regulation and we look specifically at both the IL-15 and IL-7 regulated niches to make quantitative predictions using a mathematical model. This mathematical model yields insight into the dynamics of the "Hygiene Hypothesis," and makes quantitative predictions for experiments testing the ability of passive attrition to suppress immune system disorders. The model also makes a prediction of an anti-correlation between prevalence of immune system disorders and passive attrition rates. PMID:20300517

Stromberg, Sean P; Carlson, Jean M

2010-03-16

279

Evaluation of Alternate Surface Passivation Methods (U)  

SciTech Connect

Stainless steel containers were assembled from parts passivated by four commercial vendors using three passivation methods. The performance of these containers in storing hydrogen isotope mixtures was evaluated by monitoring the composition of initially 50% H{sub 2} 50% D{sub 2} gas with time using mass spectroscopy. Commercial passivation by electropolishing appears to result in surfaces that do not catalyze hydrogen isotope exchange. This method of surface passivation shows promise for tritium service, and should be studied further and considered for use. On the other hand, nitric acid passivation and citric acid passivation may not result in surfaces that do not catalyze the isotope exchange reaction H{sub 2} + D{sub 2} {yields} 2HD. These methods should not be considered to replace the proprietary passivation processes of the two current vendors used at the Savannah River Site Tritium Facility.

Clark, E

2005-05-31

280

Passive Neutron Detection at Borders  

SciTech Connect

Radiation portal monitor systems have been deployed to screen for illicit trafficking of radioactive materials at international border crossings. This report reviews some of the neutron detection requirements and capabilities of passive detection systems used for such applications. Simulations show the effects of cargo materials on neutron spectra, different detector geometries, using a large-array of neutron detectors, and the effects of backgrounds including “ship effect” neutrons.

Kouzes, Richard T.; Siciliano, Edward R.; Ely, James H.; Keller, Paul E.; McConn, Ronald J.

2008-03-01

281

Passive longitudinal phase space linearizer  

Microsoft Academic Search

We report on the possibility to passively linearize the bunch compression process in electron linacs for the next generation x-ray free electron lasers. This can be done by using the monopole wakefields in a dielectric-lined waveguide. The optimum longitudinal voltage loss over the length of the bunch is calculated in order to compensate both the second-order rf time curvature and

P. Craievich

2010-01-01

282

Illegal passive smoking at work.  

PubMed

Introduction. Exposure to passive smoking at work has been forbidden for few years in France. This study's aim is to estimate the prevalence of passive smoking at work (PSW), the characteristics of illegal passive smoking and to identify eventual respiratory effects. Methods. Occupational practitioners (OPs) of a French county of 320,000 wage earners were contacted by mail. Then OP answered questions from a standardized questionnaire. These questions concerned the practised job, exposure features linked to PSW and health effects in relationship with second-hand smoke in workplace, and the focus on nonsmoker encountered by OP during the most recent occupational medical examination. Results. Ninety-five percent of a total group of 172 OP of Champagne county filled the postal questionnaire. More than 80% of OP's replies identified illegal PSW. The average prevalence of PSW exposure was 0.7% of the total working population. Environmental tobacco smoke (ETS) levels were considered between low and medium for most passive smokers (71%). Main features exposure to ETS at work for non-smokers was associated with female gender (69.5%), age between 40 and 49 years (41.2%) and belonging to tertiary sector (75.6%). Environmental tobacco smoke exposures at work was firstly in the office for 49.7% of the subjects and secondly in the restroom for 18% of them. Main medical symptoms encountered by non-smokers were respiratory tractus irritation (81.7%). Eighty-three percent of OPs indicated solution to eradicate PSW. Illegal PSW is really weaker than fifteen years ago. However, the findings support a real ban on smoking in the workplace in order to protect all workers. PMID:21991448

Lesage, François-Xavier; Deschamps, Frédéric; Jurca, Denisa

2011-03-31

283

Gene-environment interactions and obesity traits among postmenopausal African-American and Hispanic women in the Women's Health Initiative SHARe Study  

PubMed Central

Genome-wide association studies of obesity measures have identified associations with single nucleotide polymorphisms (SNPs). However, no large-scale evaluation of gene-environment interactions has been performed. We conducted a search of gene-environment (G×E) interactions in post-menopausal African-American and Hispanic women from the Women’s Health Initiative SNP Health Association Resource GWAS study. Single SNP linear regression on body mass index (BMI) and waist-to-hip circumference ratio (WHR) adjusted for multidimensional-scaling-derived axes of ancestry and age was run in race-stratified data with 871,512 SNPs available from African-Americans (N=8,203) and 786,776 SNPs from Hispanics (N=3,484). Tests of G×E interaction at all SNPs for recreational physical activity (met-hrs/wk), dietary energy intake (kcal/day), alcohol intake (categorical), cigarette smoking years, and cigarette smoking (ever vs. never) were run in African-Americans and Hispanics adjusted for ancestry and age at interview, followed by meta-analysis of G×E interaction terms. The strongest evidence for concordant G×E interactions in African-Americans and Hispanics was for smoking and marker rs10133840 (Q statistic P=0.70, beta=?0.01, P=3.81×10?7) with BMI as the outcome. The strongest evidence for G×E interaction within a cohort was in African-Americans with WHR as outcome for dietary energy intake and rs9557704 (SNP×kcal =?0.04, P=2.17×10?7). No results exceeded the Bonferroni–corrected statistical significance threshold.

Velez Edwards, Digna R.; Naj, Adam C.; Monda, Keri; North, Kari E.; Neuhouser, Marian; Magvanjav, Oyunbileg; Kusimo, Ibukun; Vitolins, Mara Z.; Manson, JoAnn E.; O'Sullivan, Mary Jo; Rampersaud, Evadnie; Edwards, Todd L.

2013-01-01

284

Gene-environment interactions and obesity traits among postmenopausal African-American and Hispanic women in the Women's Health Initiative SHARe Study.  

PubMed

Genome-wide association studies (GWAS) of obesity measures have identified associations with single nucleotide polymorphisms (SNPs). However, no large-scale evaluation of gene-environment interactions has been performed. We conducted a search of gene-environment (G × E) interactions in post-menopausal African-American and Hispanic women from the Women's Health Initiative SNP Health Association Resource GWAS study. Single SNP linear regression on body mass index (BMI) and waist-to-hip circumference ratio (WHR) adjusted for multidimensional-scaling-derived axes of ancestry and age was run in race-stratified data with 871,512 SNPs available from African-Americans (N = 8,203) and 786,776 SNPs from Hispanics (N = 3,484). Tests of G × E interaction at all SNPs for recreational physical activity (m h/week), dietary energy intake (kcal/day), alcohol intake (categorical), cigarette smoking years, and cigarette smoking (ever vs. never) were run in African-Americans and Hispanics adjusted for ancestry and age at interview, followed by meta-analysis of G × E interaction terms. The strongest evidence for concordant G × E interactions in African-Americans and Hispanics was for smoking and marker rs10133840 (Q statistic P = 0.70, beta = -0.01, P = 3.81 × 10(-7)) with BMI as the outcome. The strongest evidence for G × E interaction within a cohort was in African-Americans with WHR as outcome for dietary energy intake and rs9557704 (SNP × kcal = -0.04, P = 2.17 × 10(-7)). No results exceeded the Bonferroni-corrected statistical significance threshold. PMID:23192594

Velez Edwards, Digna R; Naj, Adam C; Monda, Keri; North, Kari E; Neuhouser, Marian; Magvanjav, Oyunbileg; Kusimo, Ibukun; Vitolins, Mara Z; Manson, Joann E; O'Sullivan, Mary Jo; Rampersaud, Evadnie; Edwards, Todd L

2012-11-29

285

Genome-wide association analyses of esophageal squamous cell carcinoma in Chinese identify multiple susceptibility loci and gene-environment interactions.  

PubMed

We conducted a genome-wide association study (GWAS) and a genome-wide gene-environment interaction analysis of esophageal squamous-cell carcinoma (ESCC) in 2,031 affected individuals (cases) and 2,044 controls with independent validation in 8,092 cases and 8,620 controls. We identified nine new ESCC susceptibility loci, of which seven, at chromosomes 4q23, 16q12.1, 17q21, 22q12, 3q27, 17p13 and 18p11, had a significant marginal effect (P=1.78×10(-39) to P=2.49×10(-11)) and two of which, at 2q22 and 13q33, had a significant association only in the gene-alcohol drinking interaction (gene-environment interaction P (PG×E)=4.39×10(-11) and PG×E=4.80×10(-8), respectively). Variants at the 4q23 locus, which includes the ADH cluster, each had a significant interaction with alcohol drinking in their association with ESCC risk (PG×E=2.54×10(-7) to PG×E=3.23×10(-2)). We confirmed the known association of the ALDH2 locus on 12q24 to ESCC, and a joint analysis showed that drinkers with both of the ADH1B and ALDH2 risk alleles had a fourfold increased risk for ESCC compared to drinkers without these risk alleles. Our results underscore the direct genetic contribution to ESCC risk, as well as the genetic contribution to ESCC through interaction with alcohol consumption. PMID:22960999

Wu, Chen; Kraft, Peter; Zhai, Kan; Chang, Jiang; Wang, Zhaoming; Li, Yun; Hu, Zhibin; He, Zhonghu; Jia, Weihua; Abnet, Christian C; Liang, Liming; Hu, Nan; Miao, Xiaoping; Zhou, Yifeng; Liu, Zhihua; Zhan, Qimin; Liu, Yu; Qiao, Yan; Zhou, Yuling; Jin, Guangfu; Guo, Chuanhai; Lu, Changdong; Yang, Haijun; Fu, Jianhua; Yu, Dianke; Freedman, Neal D; Ding, Ti; Tan, Wen; Goldstein, Alisa M; Wu, Tangchun; Shen, Hongbing; Ke, Yang; Zeng, Yixin; Chanock, Stephen J; Taylor, Philip R; Lin, Dongxin

2012-09-09

286

Parallel Genetic Changes and Nonparallel Gene-Environment Interactions Characterize the Evolution of Drug Resistance in Yeast  

PubMed Central

Beneficial mutations are required for adaptation to novel environments, yet the range of mutational pathways that are available to a population has been poorly characterized, particularly in eukaryotes. We assessed the genetic changes of the first mutations acquired during adaptation to a novel environment (exposure to the fungicide, nystatin) in 35 haploid lines of Saccharomyces cerevisiae. Through whole-genome resequencing we found that the genomic scope for adaptation was narrow; all adapted lines acquired a mutation in one of four late-acting genes in the ergosterol biosynthesis pathway, with very few other mutations found. Lines that acquired different ergosterol mutations in the same gene exhibited very similar tolerance to nystatin. All lines were found to have a cost relative to wild type in an unstressful environment; the level of this cost was also strongly correlated with the ergosterol gene bearing the mutation. Interestingly, we uncovered both positive and negative effects on tolerance to other harsh environments for mutations in the different ergosterol genes, indicating that these beneficial mutations have effects that differ in sign among environmental challenges. These results demonstrate that although the genomic target was narrow, different adaptive mutations can lead populations down different evolutionary pathways, with respect to their ability to tolerate (or succumb to) other environmental challenges.

Gerstein, Aleeza C.; Lo, Dara S.; Otto, Sarah P.

2012-01-01

287

Comparison of different passive knee extension torque-angle assessments.  

PubMed

Previous studies have used isokinetic dynamometry to assess joint torques and angles during passive extension of the knee, often without reporting upon methodological errors and reliability outcomes. In addition, the reliability of the techniques used to measure passive knee extension torque-angle and the extent to which reliability may be affected by the position of the subjects is also unclear. Therefore, we conducted an analysis of the intra- and inter-session reliability of two methods of assessing passive knee extension: (A) a 2D kinematic analysis coupled to a custom-made device that enabled the direct measurement of resistance to stretch and (B) an isokinetic dynamometer used in two testing positions (with the non-tested thigh either flexed at 45° or in the neutral position). The intra-class correlation coefficients (ICCs) of torque, the slope of the torque-angle curve, and the parameters of the mathematical model that were fit to the torque-angle data for the above conditions were measured in sixteen healthy male subjects (age: 21.4 ± 2.1 yr; BMI: 22.6 ± 3.3 kg m(-2); tibial length: 37.4 ± 3.4 cm). The results found were: (1) methods A and B led to distinctly different torque-angle responses; (2) passive torque-angle relationship and stretch tolerance were influenced by the position of the non-tested thigh; and (3) ICCs obtained for torque were higher than for the slope and for the mathematical parameters that were fit to the torque-angle curve. In conclusion, the measurement method that is used and the positioning of subjects can influence the passive knee extension torque-angle outcome. PMID:24149660

Freitas, Sandro R; Vaz, João R; Bruno, Paula M; Valamatos, Maria J; Mil-Homens, Pedro

2013-10-22

288

Active and passive fields in turbulent transport: the role of statistically preserved structures.  

PubMed

We have recently proposed that the statistics of active fields (which affect the velocity field itself) in well-developed turbulence are also dominated by the statistically preserved structures of auxiliary passive fields which are advected by the same velocity field. The statistically preserved structures are eigenmodes of eigenvalue 1 of an appropriate propagator of the decaying (unforced) passive field, or equivalently, the zero modes of a related operator. In this paper we investigate further this surprising finding via two examples of shell models, one akin to turbulent convection in which the temperature is the active scalar, and the other akin to magnetohydrodynamics in which the magnetic field is the active vector. In the first example, all the even correlation functions of the active and passive fields exhibit identical scaling behavior. The second example appears at first sight to be a counterexample: the statistical objects of the active and passive fields have entirely different scaling exponents. We demonstrate, nevertheless, that the statistically preserved structures of the passive vector dominate again the statistics of the active field, except that due to a dynamical conservation law the amplitude of the leading zero mode cancels exactly. The active vector is then dominated by the subleading zero mode of the passive vector. Our work thus suggests that the statistical properties of active fields in turbulence can be understood with the same generality as those of passive fields. PMID:12636599

Ching, Emily S C; Cohen, Yoram; Gilbert, Thomas; Procaccia, Itamar

2003-01-15

289

Mechanical measurements of passive film fracture on an austenitic stainless steel  

NASA Astrophysics Data System (ADS)

The initiation of fracture in passive films formed on a 304 stainless steel has been measured using a nanoindentation technique as well as bulk circumferentially notched tensile bars (CNTBs). The nanoindentation method was coupled with scanning probe microscopy to isolate individual grains that were free of any observable inclusions, so as to probe only the properties of the film upon the base alloy. The mechanical response of the film was measured while being anodically polarized in 0.1 M sulfuric acid with various halide concentrations, as well as with respect to the applied potential. The passive film strengthened as the applied potential increased in the passive regime, possibly due to film-thickness changes. In both the bulk and nanoscale tests, the passive film-fracture strength was found to decrease with increasing salt concentration in solution, which cannot be attributed to the uniform thinning of the passive film. The correlation between the bulk and nanoscale tests demonstrates that both methods are viable options of measuring the fracture of passive films on metals. Nanoindentation results are used to estimate the applied tensile stress at film fracture between 1 and 2 GPa for an anodically grown passive film on 304 stainless steel at 0 V vs that on Ag/AgCl in 0.1 pct NaCl-0.1 M sulfuric acid.

Rodriguez-Marek, D.; Bahr, D. F.; Pang, M.

2003-06-01

290

[Adverse health effects of passive smoking].  

PubMed

Passive smoking leads to exposure to carcinogenic, teratogenic, irritant and toxic substances of tobacco smoke as a consequence of other people's smoking. There is strong evidence that passive smoking causes several diseases of major public health importance as well as leads to exacerbations of many diseases. Among children passive smoking increases the risk of middle ear infections, lower respiratory infections, asthma and sudden infant death syndrome, and among adults asthma, COPD, lung cancer and cardiovascular diseases. Passive smoking by pregnant mothers leads to impaired fetal growth and may lead to organ system developmental disturbances. Asking about passive smoking and giving professional advice about stopping such exposure should be part of evidence-based medicine for these diseases. Health care workers have a central role in the prevention of passive smoking in clinical practice and health education. PMID:22724325

Jaakkola, Maritta S; Jaakkola, Jouni J K

2012-01-01

291

Passive longitudinal phase space linearizer  

NASA Astrophysics Data System (ADS)

We report on the possibility to passively linearize the bunch compression process in electron linacs for the next generation x-ray free electron lasers. This can be done by using the monopole wakefields in a dielectric-lined waveguide. The optimum longitudinal voltage loss over the length of the bunch is calculated in order to compensate both the second-order rf time curvature and the second-order momentum compaction terms. Thus, the longitudinal phase space after the compression process is linearized up to a fourth-order term introduced by the convolution between the bunch and the monopole wake function.

Craievich, P.

2010-03-01

292

Passive Testing of Web Services  

NASA Astrophysics Data System (ADS)

This paper presents a methodology to perform passive testing based on invariants of distributed systems with time information. This approach is supported by the following idea: A set of invariants represents the most relevant expected properties of the implementation under test. Intuitively, an invariant expresses the fact that each time the system under test performs a given sequence of actions, then it must exhibit a behavior reflected in the invariant. We call these invariants local because they only check the correctness of the logs that have been recorded in each isolated system.

Andrés, César; Cambronero, M. Emilia; Núñez, Manuel

293

Integrated passive electronic signature modeling  

NASA Astrophysics Data System (ADS)

It has been observed that electronic devices emit unintentional electromagnetic energy. These emissions can create a passive radio frequency signature that can be used to characterize and eventually detect and identify the device. In support of this concept, the authors have integrated high fidelity models and simulations into a framework used to perform collection feasibility studies of unintentional electronic emissions in relevant detection scenarios. This paper will discuss the elements involved in simulating realistic electronic emissions in a complex environment, including near earth propagation, terrain model effects, and visualization techniques.

Bole, M. Kate; McGraw, Jim; Ryan, Frank; Hawley, Todd; Davis, Mike; van, Toan

2009-05-01

294

Passive tamper-indicating secure container  

Microsoft Academic Search

This paper describes a passive tamper-indicating secure container that has been designed to demonstrate concepts, features, and materials that can be used in passive container applications. (In a passive security system, physical phenomena provide visual indication of tampering.) The basic container {open_quotes}volume within a volume{close_quotes} assembly consists of a transparent plastic outer container and an aluminum inner container. Both containers

Bartberger

1993-01-01

295

Gap between active and passive solar heating  

SciTech Connect

The gap between active and passive solar could hardly be wider. The reasons for this are discussed and advantages to narrowing the gap are analyzed. Ten years of experience in both active and passive systems are reviewed, including costs, frequent problems, performance prediction, performance modeling, monitoring, and cooling concerns. Trends are analyzed, both for solar space heating and for service water heating. A tendency for the active and passive technologies to be converging is observed. Several recommendations for narrowing the gap are presented.

Balcomb, J.D.

1985-01-01

296

Comparison between passive solar and superinsulation retrofits  

Microsoft Academic Search

Concepts in energy-efficient retrofit have closely followed the shifts in energy-efficient new construction, from active solar to passive solar, to micro-load passive or superinsulation. During the summer of 1980 the National Center for Appropriate Technology retrofitted a brick bearing wall residence in Butte with a mass wall, passive solar configuration. Subsequent computer simulations indicate that the money spent on the

Quivik

1981-01-01

297

19th National passive solar conference: Proceedings  

SciTech Connect

The 19th National Passive Solar Conference was held June 25--30, 1994 in San Jose, California to provide a forum for state-of-the-art work in solar technologies. Technical papers were presented on the following topics: solar architecture, performance and analysis of passive systems; design tools; thermal mass; daylighting; passive cooling; sustainability; implementation issues; and education. Papers have been processed separately for inclusion on the data base.

Burley, S.M.; Arden, M.E.; Campbell-Howe, R.; Wilkins-Crowder, B. (eds.)

1994-01-01

298

Passive cavitation imaging with ultrasound arrays  

PubMed Central

A method is presented for passive imaging of cavitational acoustic emissions using an ultrasound array, with potential application in real-time monitoring of ultrasound ablation. To create such images, microbubble emissions were passively sensed by an imaging array and dynamically focused at multiple depths. In this paper, an analytic expression for a passive image is obtained by solving the Rayleigh–Sommerfield integral, under the Fresnel approximation, and passive images were simulated. A 192-element array was used to create passive images, in real time, from 520-kHz ultrasound scattered by a 1-mm steel wire. Azimuthal positions of this target were accurately estimated from the passive images. Next, stable and inertial cavitation was passively imaged in saline solution sonicated at 520 kHz. Bubble clusters formed in the saline samples were consistently located on both passive images and B-scans. Passive images were also created using broadband emissions from bovine liver sonicated at 2.2 MHz. Agreement was found between the images and source beam shape, indicating an ability to map therapeutic ultrasound beams in situ. The relation between these broadband emissions, sonication amplitude, and exposure conditions are discussed.

Salgaonkar, Vasant A.; Datta, Saurabh; Holland, Christy K.; Mast, T. Douglas

2009-01-01

299

Comparison between passive solar and superinsulation retrofits  

SciTech Connect

Concepts in energy-efficient retrofit have closely followed the shifts in energy-efficient new construction, from active solar to passive solar, to micro-load passive or superinsulation. During the summer of 1980 the National Center for Appropriate Technology retrofitted a brick bearing wall residence in Butte with a mass wall, passive solar configuration. Subsequent computer simulations indicate that the money spent on the passive solar retrofit would have been better spent on a superinsulation retroft. These simulations make a strong case for supenisulation as a general residential retrofit strategy.

Quivik, F.L.

1981-01-01

300

Response frequency and Exner's active-passive ratio as Rorschach indicators of flexibility.  

PubMed

Among 75 college students, response frequency from the Rorschach correlated significantly at .21 with Alternate Uses and at .20 with Match Problems (measures of divergent thinking), but not significantly (r = .07) with the Questionnaire (a self-report measure of flexibility) from the Test of Behavioral Rigidity. Contrary to hypothesis, the Active-Passive Movement Ratio from the Comprehensive System did not correlate significantly with any of these tests (r = .04-.11). Whereas Response Frequency can be seen as another reflection of ideational fluency or productivity, as long has been speculated, the conceptual and empirical links between flexibility and the ratio of active to passive movement are dubious. PMID:21162456

McCloskey, Lawrence

2010-10-01

301

Passive propulsion in vortex wakes  

NASA Astrophysics Data System (ADS)

A dead fish is propelled upstream when its flexible body resonates with oncoming vortices formed in the wake of a bluff cylinder, despite being well outside the suction region of the cylinder. Within this passive propulsion mode, the body of the fish extracts sufficient energy from the oncoming vortices to develop thrust to overcome its own drag. In a similar turbulent wake and at roughly the same distance behind a bluff cylinder, a passively mounted high-aspect-ratio foil is also shown to propel itself upstream employing a similar flow energy extraction mechanism. In this case, mechanical energy is extracted from the flow at the same time that thrust is produced. These results prove experimentally that, under proper conditions, a body can follow at a distance or even catch up to another upstream body without expending any energy of its own. This observation is also significant in the development of low-drag energy harvesting devices, and in the energetics of fish dwelling in flowing water and swimming behind wake-forming obstacles.

Beal, D. N.; Hover, F. S.; Triantafyllou, M. S.; Liao, J. C.; Lauder, G. V.

302

Passive environmental radon detector study  

SciTech Connect

There are three stages at which the ambient air concentrations of radon-222 are monitored around the Uranium Mill Tailings Remedial Action (UMTRA) Project sites: before, during, and after construction. Pre-remedial-action measurements are taken for approximately 1 year. Monitoring is conducted during the entire duration of construction, and post-remedial-action monitoring is performed for approximately 1 year. Currently, the UMTRA Project uses Radtrak[reg sign] brand alpha-track radon detectors for these environmental measurements. The purposes of radon monitoring around the UMTRA sites are (1) to determine background values around the site and pre-remedial-action conditions, (2) to control construction activities and monitor off-site releases, and (3) to compare post-remedial-action concentrations with pre-remedial-action values to demonstrate that radon concentrations have been reduced to approximately background levels. The Technical Assistance Contractor to the DOE for the UMTRA Project evaluated the performance of four different types of passive environmental radon detectors under both controlled laboratory conditions and field conditions at an unremediated UMTRA site. This study was undertaken to evaluate the accuracy and precision of four different passive, timeintegrating, environmental radon detectors in an effort to determine which brand of detector is best suited to measure environmental outdoor radon concentrations for the UMTRA Project. Voluntary manufacturer participation in the study was solicited by placing an advertisement in the Commerce Business Daily. All manufacturers participating in the study supplied the detectors and analysis free of charge.

Not Available

1992-03-01

303

Passive environmental radon detector study  

SciTech Connect

There are three stages at which the ambient air concentrations of radon-222 are monitored around the Uranium Mill Tailings Remedial Action (UMTRA) Project sites: before, during, and after construction. Pre-remedial-action measurements are taken for approximately 1 year. Monitoring is conducted during the entire duration of construction, and post-remedial-action monitoring is performed for approximately 1 year. Currently, the UMTRA Project uses Radtrak{reg_sign} brand alpha-track radon detectors for these environmental measurements. The purposes of radon monitoring around the UMTRA sites are (1) to determine background values around the site and pre-remedial-action conditions, (2) to control construction activities and monitor off-site releases, and (3) to compare post-remedial-action concentrations with pre-remedial-action values to demonstrate that radon concentrations have been reduced to approximately background levels. The Technical Assistance Contractor to the DOE for the UMTRA Project evaluated the performance of four different types of passive environmental radon detectors under both controlled laboratory conditions and field conditions at an unremediated UMTRA site. This study was undertaken to evaluate the accuracy and precision of four different passive, timeintegrating, environmental radon detectors in an effort to determine which brand of detector is best suited to measure environmental outdoor radon concentrations for the UMTRA Project. Voluntary manufacturer participation in the study was solicited by placing an advertisement in the Commerce Business Daily. All manufacturers participating in the study supplied the detectors and analysis free of charge.

Not Available

1992-03-01

304

Research Review: Gene-environment interaction (GxE) research in youth depression - a systematic review with recommendations for future research  

PubMed Central

Background Depression is a major public health problem among youth, currently estimated to affect as many as 9% of US children and adolescents. The recognition that both genes (“nature”) and environments (“nurture”) are important for understanding the etiology of depression has led to rapid growth in research exploring gene–environment interactions (GxE). However, there has been no systematic review of GxE in youth depression to date. Methods The goal of this article was to systematically review evidence on the contribution of GxE to the risk of child and adolescent depression. Though a search of PubMed and PsycINFO databases to 1 April 2010, we identified 20 candidate gene–environment interaction studies focused on depression in youth (up to age 26) and compared each study in terms of the following characteristics: research design and sample studied; measure of depression and environment used; genes explored; and GxE findings in relation to these factors. Results In total 80% of studies (n=16) found at least one significant GxE association. However, there was wide variation in methods and analyses adopted across studies, especially with respect to environmental measures used and tests conducted to estimate GxE. This heterogeneity made it difficult to compare findings and evaluate the strength of the evidence for GxE. Conclusions The existing body of GxE research on depression in youth contains studies that are conceptually and methodologically quite different, which contributes to mixed findings and makes it difficult to assess the current state of the evidence. To decrease this heterogeneity, we offer 20 recommendations that are focused on: (1) reporting GxE research; (2) testing and reporting GxE effects; (3) conceptualizing, measuring, and analyzing depression; (4) conceptualizing measuring, and analyzing environment; (5) increasing power to test for GxE; and (6) improving the quality of genetic data used. Although targeted to GxE research on depression, these recommendations can be adopted by GxE researchers focusing on other mental health outcomes.

Dunn, Erin C.; Uddin, Monica; Subramanian, S.V.; Smoller, Jordan W.; Galea, Sandro; Koenen, Karestan C.

2011-01-01

305

Effects of hydrogen on the passive film and pitting of iron  

NASA Astrophysics Data System (ADS)

The effects of hydrogen on the passive film, such as the effects of hydrogen on stability and nature of passive film, and pitting of iron were systematically investigated by various electrochemical methods and surface analytical techniques. The mechanism of the decreased stability of the passive film and increased pitting of iron caused by hydrogen were discussed. The results obtained from open circuit potentials, polarization curves and ac impedance measurements show that hydrogen decreases the stability of the passive film on iron, as indicated by decreases in the open circuit potential, the charge transfer resistance, and the increase in the anodic current in the passive region. Hydrogen changes the polarization behavior of iron from simultaneous passivation to active/passivation when the hydrogen charging current density reaches a critical value. Impedance analysis shows that increasing the film formation potential cannot improve the stability of the passive film in the presence of hydrogen. The analysis of impedance data also shows that hydrogen decreases the thickness of the passive film. The results obtained from pitting induction time, pitting potential and electrochemical noise measurements, and the scanning reference electrode technique show that hydrogen significantly increases the pitting susceptibility of iron as indicated by a decreased pitting induction time and pitting potential. Iron covered by a passive film formed at a high film formation potential has a high pitting resistance. Hydrogen significantly increases the number and magnitude of current fluctuations, which are coupled by simultaneous potential fluctuations. This indicates that hydrogen might increase the initiation and growth of metastable pits. Analyses of Power Spectrum Densities (PSDs) of current fluctuations show that hydrogen decreases the repassivation rate of metastable pits, which may be the reason for the increased pitting susceptibility of iron. The presence of hydrogen in the passive film significantly affects the electronic properties of the passive film. It was found that hydrogen increases donor density in the passive films formed at various film formation potentials and the extent of donor density depends upon the film formation potential. It was also found that hydrogen decreases the band gap energy of the passive films formed at potentials lower than 0.6V. The effects of hydrogen on the donor density and band gap energy of the passive film are correlated with the effect of hydrogen on the pitting resistance of iron. Surface analyses by AES, SIMS and NRA show that hydrogen decreases the film thickness and the oxygen content in the passive film. It also increases the contents of iron and hydroxyl ions in the passive film. The effects of hydrogen on the stability of the passive film and pitting of iron have been discussed in terms of the effects of hydrogen on the composition, thickness and structure of the passive film on iron.

Yu, Jianguo

306

PASSIVE ANTIBODY AND THE IMMUNE RESPONSE  

PubMed Central

The isoimmune response of fowl inoculated with RBC coated with antibody was investigated. Anti-B antiserum from a single animal was used to coat different donor type RBC. With each donor type RBC the immune response to the coated determinants is suppressed. Enhancement of the immune response to noncoated determinants occurs when they are products of an allelic gene or belong to a different blood group system. Coating some B antigen determinants suppresses the response to noncoated determinants of the same antigen, i.e., determinants which are products of the same B gene. Varying the quantity of passive antibody revealed that the degree of suppression and the degree of enhancement are negatively correlated. These findings support the concept that antibody-coated determinants function as carrier for noncoated determinants, provided a certain physical association exists between them. A further interpretation of these studies is that in certain situations an antibody to one antigen may interfere with events which lead to an immune response to a different antigen. The possibility, that the protection afforded by ABO incompatibility against Rh isoimmunization is because of a similar phenomenon, is discussed. A hypothesis is presented which states that where the immune response to certain antigens behaves as a dominantly inherited trait, and is associated with histocompatibility type, the nonresponder animals possess an antibody (perhaps cell bound) which interferes with the response to determinants for which it does not have specificity. Responders are assumed to lack this antibody because it has specificity for their major histocompatibility antigens.

McBride, Raymond A.; Schierman, Louis W.

1971-01-01

307

Surface passivation for germanium photovoltaic cells  

Microsoft Academic Search

Passivation of a germanium surface has proved to be challenging. Various materials have been examined for this purpose, like for example silicon nitride and amorphous silicon. In this work the optimisation of PECVD amorphous silicon and the influence of the preliminary surface treatment for passivation purposes are described. Furthermore, experiments done to extract the surface recombination velocity and the bulk

N. E. Posthuma; G. Flamand; W. Geens; J. Poortmans

2005-01-01

308

Ambient stability of chemically passivated germanium interfaces  

Microsoft Academic Search

The stability of any semiconductor surface passivating layer is key to applications. Second harmonic generation (SHG) can be used to probe the chemical state of semiconductor interfaces, as well as investigate the mechanisms of chemical transformation. While the SHG rotational anisotropy changes upon sulfidation or alkylation of Ge surfaces, SHG appears far less sensitive to H and Cl passivation of

D. Bodlaki; H. Yamamoto; D. H. Waldeck; E. Borguet

2003-01-01

309

Passive behaviour of zirconium, hafnium and niobium.  

National Technical Information Service (NTIS)

The paper deals mainly with the results of stationary and transient polarization measurements together with capacitance measurements on passive electrodes of Zr, Hf and Nb over the entire pH-scale. The passive current densities are exstremely low, and ess...

S. Hornkjoel

1990-01-01

310

Subduction initiation at passive margins: Numerical modeling  

Microsoft Academic Search

Subduction is a key process for terrestrial plate tectonics, but its initiation is still not entirely understood. In particular, despite the abundance of both passive and active continental margins on Earth, no obvious cases of transition between them have been identified so far. It has been shown that at most passive margins, elastic and frictional forces exceed gravitational instability and

K. Nikolaeva; T. V. Gerya; F. O. Marques

2010-01-01

311

EVALUATION OF PASSIVE SAMPLING DEVICES (PSDS)  

EPA Science Inventory

The basic objectives of this study were to evaluate the performance of the EPA passive sampling device (PSD) for sampling of ambient level volatile organic compounds (VOC's); to develop an understanding of the mechanics of passive sampling using reversible adsorption; and to appl...

312

Digital beamforming for Passive Coherent Location radar  

Microsoft Academic Search

The paper presents digital beamforming for Passive Coherent Location (PCL) radar. The considered circular antenna array is a part of a passive system developed at Warsaw University of Technology. The system is based on FM radio transmitters. The array consists of eight half-wave dipoles arranged in a circular array covering 360deg with multiple beams. The digital beamforming procedure is presented,

Mateusz Malanowski; Krzysztof Kulpa

2008-01-01

313

Adaptive Multipath Cancellation Algorithm in Passive Radar  

Microsoft Academic Search

In passive radar system, multipath components including direct wave heavily degrades the performance of target detecting. This paper is focused on adaptive multipath cancellation algorithm in passive radar. In order to evaluate the level of cancellation required, the self-ambiguity of FM is analyzed, and the necessary minimum ratio of interference suppressed is brought forward. According to the similarity of multipath

Kui Wang; Ran Tao; Yongfeng Ma; Tao Shan

2006-01-01

314

Passive Radar using Multiple GSM Transmitting Stations  

Microsoft Academic Search

The atmosphere has a wide range of transmissions available from various sources like TV transmissions, GSM signals, FM Radio, AM Radio, GPS signals, etc. These signals open up the opportunity of designing different types of passive radars. Passive radar using a single GSM transmitting station have been designed, but this type of radar cannot give accurate target parameters. This paper

U. M. D. Mendi; B. K. Sarkar

2006-01-01

315

Region-Enhanced Passive Radar Imaging  

Microsoft Academic Search

Abstract We adapt and apply a recently-developed region-enhanced synthetic aperture radar (SAR) image reconstruction technique to the problem of passive radar imaging. One goal in passive radar imaging is to form images of aircraft using signals transmitted by commercial radio and television stations that are reflected from the objects of interest. This involves reconstructing an image from sparse samples of

Mujdat Cetin; Aaron D. Lanterman

2004-01-01

316

Ambiguity function study for UMTS Passive Radar  

Microsoft Academic Search

Passive Radar systems, also referred to as Passive Coherent Location systems (PCL),exploit reflections from illuminators of opportunity in order to detect and track objects. Over the last few years there has been an evolution of mobile networks towards the third generation radio wireless communications (3G) as UMTS (Universal Mobile Telecommunications System). The UMTS is the European standard for 3G wireless

Dario Petri; Amerigo Capria; Marco Martorella; Fabrizio Berizzi

2009-01-01

317

Passive-solar multi-family concepts  

NASA Astrophysics Data System (ADS)

The potential for saving energy and money through the use of passive solar techniques in multi family buildings is examined. Seven designs for passive solar apartment/townhouse buildings are presented. Each design is described and illustrated. The buildings are sited in Indiana, Michigan, Missouri, Ohio, South Dakota, and Minnesota.

1981-08-01

318

Passivation of metal contaminants on cracking catalyst  

Microsoft Academic Search

A contaminating metal on a cracking catalyst used for the cracking of hydrocarbons is passivated by contacting the catalyst with a hydrocarbon gas or mixture of gases comprising molecules of three carbon atoms or less at passivation reaction conditions prior to the cycling of the catalyst to the cracking zone, which conditions include a temperature in excess of 1300° F.

C. Castillo; J. C. Hayes

1983-01-01

319

Passivation of metal contaminants on cracking catalyst  

Microsoft Academic Search

A contaminating metal on a cracking catalyst used for the cracking of hydrocarbons is passivated by contacting the catalyst with a hydrocarbon gas or mixture of gases comprising molecules of three carbon atoms or less at passivation reaction conditions prior to the cycling of the catalyst to the cracking zone. The cracking catalyst comprises crystalline aluminosilicate contained in a substantially

J. C. Hayes; C. Castillo

1984-01-01

320

Passivation of metal contaminants on cracking catalyst  

Microsoft Academic Search

A contaminating metal on a cracking catalyst used for the cracking of hydrocarbons is passivated by contacting the catalyst with a hydrocarbon gas or mixture of gases comprising molecules of three carbon atoms or less at passivation reaction conditions prior to the cycling of the catalyst to the cracking zone.

C. Castillo; J. C. Hayes

1982-01-01

321

Exploiting Perceptual Illusions to Enhance Passive Haptics  

Microsoft Academic Search

Passive haptic feedback is very compelling, but a different physical object is needed for each virtual object requiring haptic feedback. I propose to enhance passive haptics by exploiting visual dominance, enabling a single physical object to provide haptic feedback for many differently shaped virtual objects. Potential applications include virtual prototyping, redirected walking, entertainment, art, and training.

Luv Kohli

322

Local positioning with passive UHF RFID transponders  

Microsoft Academic Search

This paper describes the theory of distance measurements with passive UHF transponders using the principle of modulated backscattering. The method was evaluated with the analogue frontend of a passive RFID chip for the UHF range. The chip was designed in a 0.14mum CMOS technology.

Juergen Heidrich; Daniel Brenk; Jochen Essel; Georg Fischer; Robert Weigel; Stefan Schwarzer

2009-01-01

323

Coupling passive sensors to UHF RFID tags  

Microsoft Academic Search

Coupling passive sensor data to existing UHF RFID tags explores the possibility for low volume applications without designing a new tag ASIC. The existing UHF RFID system can be used to convey additional data by overlaying a coupling loop on the tag antenna and modulating vector backscatter. The design of the RFID passive sensor prototype is presented and the feasibility

Huan-Yang Chen; Sangchul Bae; Atul Bhadkamkar; Yue Weng Mak; Daniel W. van der Weide

2012-01-01

324

Passive solar cooling of an agricultural warehouse  

Microsoft Academic Search

The thermal performance of a warehouse subjected to three different passive cooling concepts was investigated with the aid of a computer simulation model. The passive cooling concepts included logic controlled ventilation cooling, a solar driven thermosiphon wall, and building material (thermal and radiative) property modifications together with energy storage in the bulk of the building contents. The algorithm was formed

J. T. Beard; J. H. Arthur; D. P. Childs; D. G. Fletcher

1983-01-01

325

A compact real time passive terahertz imager  

Microsoft Academic Search

Passive millimetre wave imaging is now an established and accepted technology that is finding viable commercial applications in many areas, particularly security and border control. The upper frequency of operation has largely been governed by the availability of solid state uncooled detectors to around 100GHz. Passive operation at higher frequencies potentially offers some unique features such as higher optical resolution

Chris Mann

2006-01-01

326

Using gene-environment interaction analyses to clarify the role of well-done meat and heterocyclic amine exposure in the etiology of colorectal polyps123  

PubMed Central

Background: The role of well-done meat intake and meat-derived mutagen heterocyclic amine (HCA) exposure in the risk of colorectal neoplasm has been suggested but not yet established. Objective: With the use of gene-environment interaction analyses, we sought to clarify the association of HCA exposure with colorectal polyp risk. Design: In a case-control study including 2057 colorectal polyp patients and 3329 controls, we evaluated 16 functional genetic variants to construct an HCA-metabolizing score. To derive dietary HCA-exposure amount, data were collected regarding dietary intake of meat by cooking method and degree of doneness. Results: A 2-fold elevated risk associated with high red meat intake was found for colorectal polyps or adenomas in subjects with a high HCA-metabolizing risk score, whereas the risk was 1.3- to 1.4-fold among those with a low risk score (P-interaction ? 0.05). The interaction was stronger for the risk of advanced or multiple adenomas, in which an OR of 2.8 (95% CI: 1.8, 4.6) was observed for those with both a high HCA-risk score and high red meat intake (P-interaction = 0.01). No statistically significant interaction was found in analyses that used specific HCA exposure derived from dietary data. Conclusion: High red meat intake is associated with an elevated risk of colorectal polyps, and this association may be synergistically modified by genetic factors involved in HCA metabolism.

Fu, Zhenming; Shrubsole, Martha J; Li, Guoliang; Smalley, Walter E; Hein, David W; Chen, Zhi; Shyr, Yu; Cai, Qiuyin; Ness, Reid M

2012-01-01

327

Evidence of gene-environment interaction for the RUNX2 gene and environmental tobacco smoke in controlling the risk of cleft lip with/without cleft palate.  

PubMed

This study examined the association between 49 markers in the Runt-related transcription factor 2 (RUNX2) gene and nonsyndromic cleft lip with/without cleft palate (CL/P) among 326 Chinese case-parent trios, while considering gene-environment (GxE) interaction and parent-of-origin effects. Five single-nucleotide polymorphisms (SNPs) showed significant evidence of linkage and association with CL/P and these results were replicated in an independent European sample of 825 case-parent trios. We also report compelling evidence for interaction between markers in RUNX2 and environmental tobacco smoke (ETS). Although most marginal SNP effects (i.e., ignoring maternal exposures) were not statistically significant, eight SNPs were significant when considering possible interaction with ETS when testing for gene (G) and GxE interaction simultaneously or when considering GxE alone. Independent samples from European populations showed consistent evidence of significant GxETS interaction at two SNPs (rs6904353 and rs7748231). Our results suggest genetic variation in RUNX2 may influence susceptibility to CL/P through interacting with ETS. PMID:22241686

Wu, Tao; Fallin, M Daniele; Shi, Min; Ruczinski, Ingo; Liang, Kung Yee; Hetmanski, Jacqueline B; Wang, Hong; Ingersoll, Roxann G; Huang, Shangzhi; Ye, Xiaoqian; Wu-Chou, Yah-Huei; Chen, Philip K; Jabs, Ethylin Wang; Shi, Bing; Redett, Richard; Scott, Alan F; Murray, Jeffrey C; Marazita, Mary L; Munger, Ronald G; Beaty, Terri H

2012-01-12

328

Gene-gene and gene-environment interactions in HIV-associated nephropathy: A focus on the MYH9 nephropathy susceptibility gene.  

PubMed

HIV-associated nephropathy (HIVAN) is a leading cause of ESRD in African Americans. The HIV-1 virus infects podocytes, cells integral to formation of the glomerular filtration barrier, often leading to focal segmental glomerulosclerosis. HIVAN is typically a complication of late-stage HIV infection, associated with low CD4 cell counts and elevated serum HIV RNA levels. Highly active antiretroviral therapy is partially protective and has altered the natural history of HIV-associated kidney disease. Nonetheless, HIVAN remains an important public health concern among HIV-infected African Americans. Although polymorphisms in the MYH9 gene on chromosome 22 are strongly associated with HIVAN, as well as with idiopathic focal segmental glomerulosclerosis and global glomerulosclerosis (historically labeled "hypertensive nephrosclerosis"), the majority of HIV-infected patients who are genetically at risk from MYH9 do not appear to develop severe kidney disease. Therefore, we postulate that additional environmental exposures and/or inherited factors are necessary to initiate human HIVAN. Gene-environment interactions have also been proposed as necessary for the initiation of HIVAN in murine models. It is important that these novel risk factors be identified because prevention of environmental exposures and targeting of additional gene products may reduce the risk for HIVAN, even among those harboring 2 risk alleles in MYH9. PMID:20005488

Núñez, Marina; Saran, Anita M; Freedman, Barry I

2010-01-01

329

Gene-Gene and Gene-Environment Interactions in HIV-Associated Nephropathy: a Focus on the MYH9 Nephropathy Susceptibility Gene  

PubMed Central

Human immunodeficiency virus-associated nephropathy (HIVAN) is a leading cause of end-stage renal disease in African Americans. The HIV-1 virus infects podocytes, cells integral to formation of the glomerular filtration barrier, often leading to focal segmental glomerulosclerosis. HIVAN is typically a complication of late-stage HIV infection, associated with low CD4 cell counts and elevated serum HIV RNA levels. Highly active antiretroviral therapy (HAART) is partially protective and has altered the natural history of HIV-associated kidney disease. Nonetheless, HIVAN remains an important public health concern among HIV-infected African Americans. Although polymorphisms in the MYH9 gene on chromosome 22 are strongly associated with HIVAN, as well as with idiopathic focal segmental glomerulosclerosis and global glomerulosclerosis (historically labeled "hypertensive nephrosclerosis"), the majority of HIV-infected patients who are genetically at risk from MYH9 do not appear to develop severe kidney disease. Therefore, we postulate that additional environmental exposures and/or inherited factors are necessary to initiate human HIVAN. Gene-environment interactions have also been proposed as necessary for initiation of HIVAN in murine models. It is important that these novel risk factors be identified, as prevention of environmental exposures and targeting of additional gene products may reduce the risk for HIVAN, even among those harboring two risk alleles in MYH9.

Nunez, Marina; Saran, Anita M.; Freedman, Barry I.

2009-01-01

330

Autism risk factors: genes, environment, and gene-environment interactions  

PubMed Central

The aim of this review is to summarize the key findings from genetic and epidemiological research, which show that autism is a complex disorder resulting from the combination of genetic and environmental factors. Remarkable advances in the knowledge of genetic causes of autism have resulted from the great efforts made in the field of genetics. The identification of specific alleles contributing to the autism spectrum has supplied important pieces for the autism puzzle. However, many questions remain unanswered, and new questions are raised by recent results. Moreover, given the amount of evidence supporting a significant contribution of environmental factors to autism risk, it is now clear that the search for environmental factors should be reinforced. One aspect of this search that has been neglected so far is the study of interactions between genes and environmental factors.

Chaste, Pauline; Leboyer, Marion

2012-01-01

331

Passive Phase Noise Cancellation Scheme  

NASA Astrophysics Data System (ADS)

We introduce a new method for reducing phase noise in oscillators, thereby improving their frequency precision. The noise reduction is realized by a passive device consisting of a pair of coupled nonlinear resonating elements that are driven parametrically by the output of a conventional oscillator at a frequency close to the sum of the linear mode frequencies. Above the threshold for parametric instability, the coupled resonators exhibit self-oscillations which arise as a response to the parametric driving, rather than by application of active feedback. We find operating points of the device for which this periodic signal is immune to frequency noise in the driving oscillator, providing a way to clean its phase noise. We present results for the effect of thermal noise to advance a broader understanding of the overall noise sensitivity and the fundamental operating limits.

Kenig, Eyal; Cross, M. C.; Lifshitz, Ron; Karabalin, R. B.; Villanueva, L. G.; Matheny, M. H.; Roukes, M. L.

2012-06-01

332

Passive flow control by membrane wings for aerodynamic benefit  

NASA Astrophysics Data System (ADS)

The coupling of passive structural response of flexible membranes with the flow over them can significantly alter the aerodynamic characteristic of simple flat-plate wings. The use of flexible wings is common throughout biological flying systems inspiring many engineers to incorporate them into small engineering flying systems. In many of these systems, the motion of the membrane serves to passively alter the flow over the wing potentially resulting in an aerodynamic benefit. In this study, the aerodynamic loads and the flow field for a rigid flat-plate wing are compared to free trailing-edge membrane wings with two different pre-tensions at a chord-based Reynolds number of approximately 50,000. The membrane was silicon rubber with a scalloped free trailing edge. The analysis presented includes load measurements from a sting balance along with velocity fields and membrane deflections from synchronized, time-resolved particle image velocimetry and digital image correlation. The load measurements demonstrate increased aerodynamic efficiency and lift, while the synchronized flow and membrane measurements show how the membrane motion serves to force the flow. This passive flow control introduced by the membranes motion alters the flows development over the wing and into the wake region demonstrating how, at least for lower angles of attack, the membranes motion drives the flow as opposed to the flow driving the membrane motion.

Timpe, Amory; Zhang, Zheng; Hubner, James; Ukeiley, Lawrence

2013-03-01

333

Passive micromixer for luminol-peroxide chemiluminescence detection.  

PubMed

This paper reports a microchip with an integrated passive micromixer based on chaotic advection. The micromixer with staggered herringbone structures was used for luminol-peroxide chemiluminescence detection. The micromixer was examined to assess its suitability for chemiluminescence reaction. The relationship between the flow rate and the location of maximum chemiluminescence intensity was investigated. The light intensity was detected using an optical fiber attached along the mixing channel and a photon detector. A linear correlation between chemiluminescence intensity and the concentration of cobalt(ii) ions or hydrogen peroxide was observed. This microchip has a potential application in environmental monitoring for industries involved in heavy metals and in medical diagnostics. PMID:21552614

Lok, Khoi Seng; Kwok, Yien Chian; Nguyen, Nam-Trung

2011-05-09

334

Passive microwave tags : LDRD 52709, FY04 final report.  

SciTech Connect

This report describes both a general methodology and specific examples of completely passive microwave tags. Surface acoustic wave (SAW) devices were used to make tags for both identification and sensing applications at different frequencies. SAW correlators were optimized for wireless identification, and SAW filters were developed to enable wireless remote sensing of physical properties. Identification tag applications and wireless remote measurement applications are discussed. Significant effort went into optimizing the SAW devices used for this work, and the lessons learned from that effort are reviewed.

Brocato, Robert Wesley

2004-10-01

335

Passive Auditory Stimulation Improves Vision in Hemianopia  

PubMed Central

Techniques employed in rehabilitation of visual field disorders such as hemianopia are usually based on either visual or audio-visual stimulation and patients have to perform a training task. Here we present results from a completely different, novel approach that was based on passive unimodal auditory stimulation. Ten patients with either left or right-sided pure hemianopia (without neglect) received one hour of unilateral passive auditory stimulation on either their anopic or their intact side by application of repetitive trains of sound pulses emitted simultaneously via two loudspeakers. Immediately before and after passive auditory stimulation as well as after a period of recovery, patients completed a simple visual task requiring detection of light flashes presented along the horizontal plane in total darkness. The results showed that one-time passive auditory stimulation on the side of the blind, but not of the intact, hemifield of patients with hemianopia induced an improvement in visual detections by almost 100% within 30 min after passive auditory stimulation. This enhancement in performance was reversible and was reduced to baseline 1.5 h later. A non-significant trend of a shift of the visual field border toward the blind hemifield was obtained after passive auditory stimulation. These results are compatible with the view that passive auditory stimulation elicited some activation of the residual visual pathways, which are known to be multisensory and may also be sensitive to unimodal auditory stimuli as were used here. Trial Registration DRKS00003577

Lewald, Jorg; Tegenthoff, Martin; Peters, Soren; Hausmann, Markus

2012-01-01

336

Passive Elastic Properties of the Rat Ankle  

PubMed Central

Passive properties of muscles and tendons, including their elasticity, have been suggested to influence motor control. We examine here the potential role of passive elastic muscle properties at the rat ankle joint, focusing on their potential to specify an equilibrium position of the ankle. We measured the position-dependent passive torques at the rat ankle before and after sequential cuts of flexor (a.k.a. dorsiflexor) and extensor (a.k.a. plantarflexor) ankle muscles. We found that there was a passive equilibrium position of the ankle that shifted systematically with the cuts, demonstrating that the passive torques produced by ankle flexor and extensor muscles work in opposition in order to maintain a stable equilibrium. The mean equilibrium position of the intact rat ankle ranged from 9.3–15.7 degrees in extension, depending on the torque metric. The mean shift in equilibrium position due to severing extensors ranged from 4.4–7.7 degrees, and the mean shift due to severing flexors was smaller, ranging from 0.9–2.5 degrees. The restoring torques generated by passive elasticity are large enough (approximately 1.5–5mNm for displacements of 18 degrees from equilibrium) to affect ankle movement during the swing phase of locomotion, and the asymmetry of larger extension vs. flexion torques is consistent with weight support, demonstrating the importance of accounting for passive muscle properties when considering the neural control of movement.

Wu, Mengnan (Mary); Pai, Dinesh. K.; Tresch, Matthew. C.; Sandercock, Thomas G.

2013-01-01

337

Improving the resolution of bearing in passive sonar arrays by eigenvalue analysis  

Microsoft Academic Search

A method of improving the bearing-resolving capabilities of a passive array is discussed. This method is an adaptive beamforming method, having many similarities to the minimum energy approach. The evaluation of energy in each steered beam is preceded by an eigenvalue-eigenvector analysis of the empirical correlation matrix. Modification of the computations according to the eigenvalue structure results in improved resolution

DON H. JOHNSON; STUART R. DEGRAAF

1982-01-01

338

Adaptive bearing estimation and tracking of multiple targets in a realistic passive sonar scenario  

Microsoft Academic Search

In a realistic passive sonar environment, the received signal consists of multipath arrivals from closely separated moving targets. The signals are contaminated by spatially correlated noise. The differential MUSIC has been proposed to estimate the DOAs in such a scenario. This method estimates the 'noise subspace' in order to estimate the DOAs. However, the 'noise subspace' estimate has to be

R. Rajagopal; Subhash Challa; Farhan A. Faruqi; P. R. Rao

1997-01-01

339

Oblique rifting and segmentation of the NE Gulf of Aden passive margin  

Microsoft Academic Search

The Gulf of Aden is a young, obliquely opening, oceanic basin where tectonic structures can easily be followed and correlated from the passive margins to the active mid-oceanic ridge. It is an ideal laboratory for studies of continental lithosphere breakup from rifting to spreading. The northeastern margin of the Gulf of Aden offers the opportunity to study on land the

Marc Fournier; Nicolas Bellahsen; Olivier Fabbri; Yanni Gunnell

2004-01-01

340

Relationship between environmental tobacco smoke and urinary cotinine levels in passive smokers at their residence  

Microsoft Academic Search

Studies of the health effects of environmental tobacco smoke (ETS) using measured air concentrations are subject to bias. Cotinine, a nicotine metabolite detected in urine, has been recommended as a quantitative measure of nicotine intake and thus as a marker for ETS exposure in humans. The aim of this study was to correlate home indoor ETS levels with passive smokers’

Hyojin Kim; Youngwook Lim; Seokju Lee; Changsoo Kim; Cheinsoo Hong; Dongchun Shin

2004-01-01

341

High-frequency simulations and compact models compared with measurements for passive on-chip components  

Microsoft Academic Search

Dedicated on-chip passive test structures to test the quality of high-frequency simulations and compact models are described. Based upon the simulations a compact (SPICE) model is calculated. The paper shows the quantitative correlation between measurements and simulations for a resistor, a coplanar line and a metal insulator metal capacitor. Agreement of less than 10 % is obtained between measurements and

Peter Meuris; Gabriela Ciuprina; Ehrenfried Seebacher

2005-01-01

342

Second order modeling of a passive scalar in a turbulent shear flow  

Microsoft Academic Search

A realizability concept for the scalar flux is described, and a new model form of the pressure correlation term in the passive scalar flux equations is carefully derived based on realizability. A modeled scalar dissipation equation is proposed based on the idea that the ratio of mechanical time scale to scalar time scale tends toward an equilibrium value during the

T.-H. Shih; J. L. Lumley; J.-Y. Chen

1989-01-01

343

Cretaceous sequence stratigraphy of the Northern South American Passive Margin: Implications for tectonic evolution  

SciTech Connect

The passive margin of northern South America, from Colombia to northeastern Venezuela, was relatively stable through the Cretaceous and only broadly affected by the entry of the Caribbean Plate into the Protocaribbean Basin. This region offers a unique opportunity to test the relative effects of global sealevel change, autocyclic sedimentologic processed, and regional tectonics in shaping the stratigraphic record of Cretaceous passive margins. High-resolution stratigraphic studies of Colombia and Venezuela have established a precise system of regional chronology and correlation with resolution <1 Ma (50-500 ka for the middle Cretaceous). This allows precise separation of allocyclic and autocyclic controls on facies development. This new chronology integrates assemblage zone biostratigraphy with event/cycle chronostratigraphy. Newly measured Cretaceous sections in Venezuela and throughout Colombia are calibrated to this new chronology, and sequence stratigraphic units independently defined to the third-order of resolution. Graphic correlation of all sections is used to identify sequences with regional stratigraphic expression, and those which correlate to sequence stratigraphic standards of North America, Europe and the global cycles of Hag et al. (1988). 50-60 percent of the stratigraphic sequences across the South American passive margin correlate to other continents and to the global sequence stratigraphic standard, reflecting strong eustatic influence on Cretaceous sedimentation across northern South America. The remaining sequences in this region reflect tectonic modification of the passive margin and autocyclic sedimentary processes.

Kauffman, E.G.; Villamil, T.; Johnson, C.C. (Univ. of Colorado, Boulder, CO (United States))

1993-02-01

344

Passive-sensor data fusion  

NASA Astrophysics Data System (ADS)

Problems in multi-sensor data fusion are addressed for passive (angle-only) sensors; the example used is a constellation of IR sensors on satellites in low-earth orbit, viewing up to several hundred ballistic missile targets. The sensor data used in the methodology of the report is 'post-detection,' with targets resolved on single pixels (it is possible for several targets to be resolved on the same pixel). A 'scan' by a sensor is modeled by the formation of a rectangular focal plane image of lit pixels (bits with value 1), representing the presence of at least one target, and unlit pixels (bits with value 0), representing the absence of a target, at a particular time. Approaches and algorithmic solutions are developed which address the following passive sensor data fusion problems: scan-to-scan target association, and association classification. The ultimate objective is to estimate target states, for use in a larger battle management system. Results indicate that successful scan-to-scan target association is feasible at scan rates >=2 Hz, independent of resolution. Sensor-to-sensor target association is difficult at low resolution; even with high-resolution sensors the performance of a standard two-sensor single scan approach is variable and unpredictable, since it is a function of the relative geometry of sensors and targets. A single-scan approach using the Varad algorithm and three sensors is not as sensitive to this relative geometry, but is usable only for high-resolution sensors. Innovative multi-scan and multi-sensor modifications of the three- sensor Varad algorithm are developed which provide excellent performance for a wide range of sensor resolutions. The multi-sensor multi-scan methodology also provides accurate information on the classification of target associations as correct or incorrect. For the scenarios examined with resolution cell sizes ranging from 300 m to 2 km, association errors are less than 5% and essentially no classification errors are made, when sensor data is integrated over a 60 s time period. With higher-resolution sensors, better results are achievable in less time. The results of the data fusion from three or more sensors over such a period of time provide a rich source of information for the estimation of target states. The algorithms are fast (O(n ln n)); for approximately 100 targets, the average processing per scan in the multi-scan three-sensor methodology takes approximately a second of computational time on a Mac II.

Kolitz, Stephan E.

1991-08-01

345

Los Alamos National Laboratory passive solar program  

SciTech Connect

Progress in passive solar tasks performed at the Los Alamos National Laboratory for FY-81 is documented. A third volume of the Passive Solar Design Handbook is nearly complete. Twenty-eight configurations of sunspaces were studied using the solar load ratio method of predicting performance; the configuration showing best performance is discussed. The minimum level of insolation needed to generate convective flow in the thermosiphon test rig is noted and measured. Information is also included on test room performance, off-peak auxiliary electric heating for a passive home, free convection experiment, monitored buildings, and technical support to the US Department of Energy.

Neeper, D.A.

1981-01-01

346

New assistive technology for passive standing.  

PubMed

The anesthetic skin of patients with spinal cord injuries makes these patients a high-risk population for burn injuries. Innovations in rehabilitation engineering can now provide the disabled with mechanical devices that allow for passive standing. Passive standing has been shown to counteract many of the effects of chronic immobilization and spinal cord injury, including bone demineralization, urinary calculi, cardiovascular instability, and reduced joint range of motion and muscular tone. This article will describe several unique assistive devices that allow for passive standing and an improvement in daily living for people with disabilities. PMID:10188115

Gear, A J; Suber, F; Neal, J G; Nguyen, W D; Edlich, R F

347

Passivation Effects in Copper Thin Films  

SciTech Connect

We studied the influence of a 10 nm AlxOy passivation on the stress-temperature behavior of 100 nm and 1 {mu}m thick Cu films. At low temperatures, the passivation induces a large tensile stress increase in the 100 nm film; however, its effect on the 1 {mu}m film is negligible. At high temperatures, the opposite behavior is observed; while the passivation does not change the 100 nm film behavior, it strengthens the 1 {mu}m film by driving it deeper into compression. These observations are explained in light of a combination of constrained diffusional creep and dislocation dynamics unique to ultra-thin films.

Wiederhirn, G.; Nucci, J.; Richter, G.; Arzt, E. [Max Planck Institute for Metals Research, Heisenbergstr. 3, D-70569 Stuttgart (Germany); Balk, T. J. [University of Kentucky, Department of Chemical and Materials Engineering, 177 F. Paul Anderson Tower, Lexington, KY 40506-0046 (United States); Dehm, G. [Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstr. 12, A-8700 Leoben (Austria); Department Materials Physics, University of Leoben, Jahnstr. 12, A-8700 Leoben (Austria)

2006-02-07

348

Investigation into the relationship between the passive flexibility and active stiffness of the ankle plantar-flexor muscles  

Microsoft Academic Search

Objective. The purpose of the study was to investigate the relationship between measurements of passive flexibility and active stiffness of the ankle plantar-flexor muscles.Design. The study was a correlation design.Background. Flexibility has passive and active components. Little information is available regarding the relationship of these measurements in terms of the information that they yield on the state of the muscle–tendon

D. Glenn Hunter; Jonathon Spriggs

2000-01-01

349

Molecular and genomic approach for understanding the gene-environment interaction between Nrf2 deficiency and carcinogenic nickel-induced DNA damage  

PubMed Central

Nickel (II) is a toxic and carcinogenic metal which induces a redox imbalance following oxidative stress. Nuclear factor erythroid-2 related factor 2 (Nrf2) is a redox factor that regulates oxidation/reduction status and consequently mediates cytoprotective responses against exposure to environmental toxicants. In this study, we investigated the protective roles of the Nrf2 gene against oxidative stress and DNA damage induced by nickel at sub-lethal doses. Under nickel exposure conditions, we detected significantly increased intracellular ROS generation, in addition to higher amounts of DNA damage using comet assay and ?-H2AX immunofluorescence staining in Nrf2 lacking cells, as compared to Nrf2 wild-type cells. In addition, we attempted to identify potential nickel and Nrf2-responsive targets and the relevant pathway. The genomic expression data were analyzed using microarray for the selection of synergistic effect-related genes by Nrf2 knockdown under nickel treatment. In particular, altered expressions of 6 upregulated genes (CAV1, FOSL2, MICA, PIM2, RUNX1 and SLC7A6) and 4 downregulated genes (APLP1, CLSPN, PCAF and PRAME) were confirmed by qRT-PCR. Additionally, using bioinformatics tool, we found that these genes functioned principally in a variety of molecular processes, including oxidative stress response, necrosis, DNA repair and cell survival. Thus, we describe the potential biomarkers regarded as molecular candidates for Nrf2-related cellular protection against nickel exposure. In conclusion, these findings indicate that Nrf2 is an important factor with a protective role in the suppression of mutagenicity and carcinogenicity by environmental nickel exposure in terms of gene-environment interaction.

KIM, HYE LIM; SEO, YOUNG ROK

2012-01-01

350

Gene-environment interactions in the causation of neural tube defects: folate deficiency increases susceptibility conferred by loss of Pax3 function.  

PubMed

Risk of neural tube defects (NTDs) is determined by genetic and environmental factors, among which folate status appears to play a key role. However, the precise nature of the link between low folate status and NTDs is poorly understood, and it remains unclear how folic acid prevents NTDs. We investigated the effect of folate level on risk of NTDs in splotch (Sp(2)(H)) mice, which carry a mutation in Pax3. Dietary folate restriction results in reduced maternal blood folate, elevated plasma homocysteine and reduced embryonic folate content. Folate deficiency does not cause NTDs in wild-type mice, but causes a significant increase in cranial NTDs among Sp(2)(H) embryos, demonstrating a gene-environment interaction. Control treatments, in which intermediate levels of folate are supplied, suggest that NTD risk is related to embryonic folate concentration, not maternal blood folate concentration. Notably, the effect of folate deficiency appears more deleterious in female embryos than males, since defects are not prevented by exogenous folic acid. Folate-deficient embryos exhibit developmental delay and growth retardation. However, folate content normalized to protein content is appropriate for developmental stage, suggesting that folate availability places a tight limit on growth and development. Folate-deficient embryos also exhibit a reduced ratio of s-adenosylmethionine (SAM) to s-adenosylhomocysteine (SAH). This could indicate inhibition of the methylation cycle, but we did not detect any diminution in global DNA methylation, in contrast to embryos in which the methylation cycle was specifically inhibited. Hence, folate deficiency increases the risk of NTDs in genetically predisposed splotch embryos, probably via embryonic growth retardation. PMID:18753144

Burren, Katie A; Savery, Dawn; Massa, Valentina; Kok, Robert M; Scott, John M; Blom, Henk J; Copp, Andrew J; Greene, Nicholas D E

2008-08-26

351

A genome-wide association and gene-environment interaction study for serum triglycerides levels in a healthy Chinese male population.  

PubMed

Triglyceride (TG) is a complex phenotype influenced by both genetic and environmental factors. Recent genome-wide association studies (GWAS) have identified genes or loci affecting lipid levels; however, such studies in Chinese populations are limited. A two-stage GWAS were conducted to identify genetic variants that were associated with TG in a Chinese population of 3495 men. Gene-environment interactions on serum TG levels were further investigated for the seven single nucleotide polymorphisms (SNPs) that were studied in both stages. Two previously reported SNPs (rs651821 in APOA5, rs328 in LPL) were replicated in the second stage, and the combined P-values were 9.19 × 10(-26) and 1.41 × 10(-9) for rs651821 and rs328, respectively. More importantly, a significant interaction between aldehyde dehydrogenase 2 (ALDH2) rs671 and alcohol consumption on serum TG levels were observed (P = 3.34 × 10(-5)). Rs671 was significantly associated with serum TG levels in drinkers (P = 1.90 × 10(-10)), while no association was observed in non-drinkers (P > 0.05). For drinkers, men carrying the AA/AG genotype have significantly lower serum TG levels, compared with men carrying the GG genotype. For men with the GG genotype, the serum TG levels increased with the quantity of alcohol intake (P = 1.28 × 10(-8) for trend test). We identified a novel, significant interaction effect between alcohol consumption and the ALDH2 rs671 polymorphism on TG levels, which suggests that the effect of alcohol intake on TG occurs in a two-faceted manner. Just one drink can increase TG level in susceptible individuals who carry the GG genotype, while individuals carrying AA/AG genotypes may actually benefit from moderate drinking. PMID:22171074

Tan, Aihua; Sun, Jielin; Xia, Ning; Qin, Xue; Hu, Yanling; Zhang, Shijun; Tao, Sha; Gao, Yong; Yang, Xiaobo; Zhang, Haiying; Kim, Seong-Tae; Peng, Tao; Lin, Xiaoling; Li, Li; Mo, Linjian; Liang, Zhengjia; Shi, Deyi; Huang, Zhang; Huang, Xianghua; Liu, Ming; Ding, Qiang; Trent, Jeffrey M; Zheng, S Lilly; Mo, Zengnan; Xu, Jianfeng

2011-12-14

352

Complement Component 3: an assessment of association with AMD and analysis of gene-gene and gene-environment interactions in a Northern Irish cohort  

PubMed Central

Purpose A non-synonymous single nucleotide polymorphism (SNP) in complement component 3 has been shown to increase the risk of age-related macular degeneration (AMD). We assess its effect on AMD risk in a Northern Irish sample, test for gene–gene and gene–environment interaction, and review a risk prediction model. Methods SNP rs2230199 was genotyped in 1,358 samples, which comprised 437 cases, 436 no-disease controls, and 485 participants randomly sampled from the Northern Ireland population. Allele frequencies were assessed in cases and controls. Logistic regression analysis was used to assess interaction and develop a risk prediction model. Results We report a minor allele frequency of 0.248 for rs2230199 in the population (n=485), 0.296 in cases (n=437), and 0.221 in controls (n=436; odds ratio [OR]=1.48; confidence interval [CI]: 1.19–1.85; p=0.0003). The significant association is retained following multivariate analysis with adjustment for age, smoking status, Complement Factor H (CFH), Age-Related Maculopathy Susceptibility 2 (ARMS2), Complement Component 2 (CC2), and Complement Factor B (CFB; OR=1.45; CI: 1.10–1.91; p=0.009). No evidence to support an interaction between any of the covariates within the regression model was found. The area under the receiver operator characteristic curve calculated for the fully adjusted model, including all variables, was 0.86 for late AMD. Conclusions Our study confirmed the association between Complement Component 3 (C3) and late-stage AMD. There was no evidence for an interaction with environmental exposures, nor did we find data to support a gene–gene effect.

Dasari, Shilpa; Patterson, Christopher C.; Chakravarthy, Usha; Silvestri, Giuliana

2010-01-01

353

Characterization of gene-environment interactions by behavioral profiling of selectively bred rats: the effect of NMDA receptor inhibition and social isolation.  

PubMed

Gene-environment interactions have an important role in the development of psychiatric disorders. To generate and validate a new substrain of rats with signs related to schizophrenia, we used selective breeding after postweaning social isolation and chronic ketamine treatment through several generations of animals and compared the subsequent strain to naive rats that were not genetically manipulated. We further investigated whether social isolation and ketamine treatment augmented the appearance of schizophrenic-like signs in these rats. Four experimental groups were studied (n=6-15 rats/group): naive rats without any treatment (NaNo); naive rats with postweaning social isolation and ketamine treatment (NaTr); 15th generation of selectively bred animals without any treatment (SelNo) or selectively bred rats with both isolation and ketamine treatment (SelTr). The startle reaction, tail-flick and novel object recognition tests were used to classify the animals into low- or high-risk for schizophrenia. Reduced pain sensitivity, higher degree of the startle reaction, disturbed prepulse inhibition, altered motor activity and decreased differentiation index in the memory test were observed in the 15th generation of the substrain, along with enhanced grooming behavior. Five functional indices (TF latency, startle reaction, prepulse inhibition, differentiation index, and grooming activity) were rated from 0 to 2, and the analysis of the summarized score revealed that the NaNo group had the lowest overall indication of schizophrenic-like signs, while the SelTr animals scored the highest, suggesting that both heritable and environmental factors were important in the generation of the behavioral alterations. We assume that further breeding after this complex treatment may lead to a valid and reliable animal model of schizophrenia. PMID:23195116

Petrovszki, Zita; Adam, Gabor; Tuboly, Gabor; Kekesi, Gabriella; Benedek, Gyorgy; Keri, Szabolcs; Horvath, Gyongyi

2012-11-27

354

A study of gene-environment interaction on the gene for angiotensin converting enzyme: a combined functional and population based approach  

PubMed Central

Introduction: Studies on the role of the insertion/deletion (I/D) polymorphism of the gene coding for angiotensin converting enzyme (ACE) in atherosclerosis have been inconsistent. In a meta-analysis, we recently showed that this relationship is stronger in high risk populations. In this paper, we used a combined functional and population based approach to investigate the gene–environment interaction of the ACE I/D polymorphism in relation to carotid artery wall thickness. Methods: The study was part of the Rotterdam Study, a prospective population based cohort study. In 5321 subjects, IMT was measured in the carotid arteries by ultrasonography and ACE genotype was determined by size analysis of polymerase chain reaction products. Results: In multiple regression analysis, I/D polymorphism and smoking were the main determinants for plasma ACE activity (r2 = 0.28). There was a positive association between the D allele of the I/D polymorphism and carotid artery thickness among current smokers (p = 0.03). Subjects carrying only one of the risk factors (smoking or the D allele) did not show significant differences in IMT compared with the non-/former smokers group carrying two II alleles, while carriers of both risk factors had significant higher IMT. The association was not present in non-/former smokers. Discussion: The results provide further evidence that genetic and environmental factors interact in the formation of the arterial lesions. This study shows that large population based studies can be extremely helpful in unravelling the genetic origin of complex diseases such as atherosclerosis.

Sayed-Tabatabaei, F; Schut, A; Hofman, A; Bertoli-Avella, A; Vergeer, J; Witteman, J; van Duijn, C M

2004-01-01

355

Synthesis of passive microwave and radar altimeter data for estimating accumulation rates of dry polar snow  

Microsoft Academic Search

In this paper, we compare dry-snow extinction coefficients derived from satellite radar altimeter data with brightness temperature data from passive microwave measurements over a portion of the East Antarctic plateau. The comparison between the extinction coefficients and the brightness temperatures shows a strong negative correlation, where the correlation coefficients ranged from –0·87 to –0·95. The large-scale trend shows that the

C. H. Davis

1995-01-01

356

Passive solar roof ice melter  

SciTech Connect

An elongated passive solar roof ice melter is placed on top of accumulated ice and snow including an ice dam along the lower edge of a roof of a heated building and is held against longitudinal movement with respect to itself. The melter includes a bottom wall having an upper surface highly absorbent to radiant solar energy; a first window situated at right angles with respect to the bottom wall, and a reflecting wall connecting the opposite side edges of the bottom wall and the first window. The reflecting wall has a surface facing the bottom wall and the window which is highly reflective to radiant solar energy. Radiant solar energy passes through the first window and either strikes the highly absorbent upper surface of the bottom wall or first strikes the reflecting wall to be reflected down to the upper surface of the bottom wall. The heat generated thereby melts through the ice below the bottom wall causing the ice dam to be removed between the bottom wall and the top of the roof and immediately adjacent to the ice melter along the roof. Water dammed up by the ice dam can then flow down through this break in the dam and drain out harmlessly onto the ground. This prevents dammed water from seeping back under the shingles and into the house to damage the interior of the house.

Deutz, R.T.

1981-09-29

357

Passive fault current limiting device  

DOEpatents

A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment. 6 figs.

Evans, D.J.; Cha, Y.S.

1999-04-06

358

Passive detection of vehicle loading  

NASA Astrophysics Data System (ADS)

The Digital Imaging and Remote Sensing Laboratory (DIRS) at the Rochester Institute of Technology, along with the Savannah River National Laboratory is investigating passive methods to quantify vehicle loading. The research described in this paper investigates multiple vehicle indicators including brake temperature, tire temperature, engine temperature, acceleration and deceleration rates, engine acoustics, suspension response, tire deformation and vibrational response. Our investigation into these variables includes building and implementing a sensing system for data collection as well as multiple full-scale vehicle tests. The sensing system includes; infrared video cameras, triaxial accelerometers, microphones, video cameras and thermocouples. The full scale testing includes both a medium size dump truck and a tractor-trailer truck on closed courses with loads spanning the full range of the vehicle's capacity. Statistical analysis of the collected data is used to determine the effectiveness of each of the indicators for characterizing the weight of a vehicle. The final sensing system will monitor multiple load indicators and combine the results to achieve a more accurate measurement than any of the indicators could provide alone.

McKay, Troy R.; Salvaggio, Carl; Faulring, Jason W.; Salvaggio, Philip S.; McKeown, Donald M.; Garrett, Alfred J.; Coleman, David H.; Koffman, Larry D.

2012-02-01

359

PASSIVE DETECTION OF VEHICLE LOADING  

SciTech Connect

The Digital Imaging and Remote Sensing Laboratory (DIRS) at the Rochester Institute of Technology, along with the Savannah River National Laboratory is investigating passive methods to quantify vehicle loading. The research described in this paper investigates multiple vehicle indicators including brake temperature, tire temperature, engine temperature, acceleration and deceleration rates, engine acoustics, suspension response, tire deformation and vibrational response. Our investigation into these variables includes building and implementing a sensing system for data collection as well as multiple full-scale vehicle tests. The sensing system includes; infrared video cameras, triaxial accelerometers, microphones, video cameras and thermocouples. The full scale testing includes both a medium size dump truck and a tractor-trailer truck on closed courses with loads spanning the full range of the vehicle's capacity. Statistical analysis of the collected data is used to determine the effectiveness of each of the indicators for characterizing the weight of a vehicle. The final sensing system will monitor multiple load indicators and combine the results to achieve a more accurate measurement than any of the indicators could provide alone.

Garrett, A.

2012-01-03

360

Physiological correlates of learned helplessness in man  

Microsoft Academic Search

Assessed physiological correlates (heart rate, skin resistance, and GSR) of learned helplessness in 48 undergraduates. One group of Ss was pretreated with a series of inescapable aversive tones, and the degree of impairment was measured on a subsequent solvable anagram solution task. These Ss were compared with a group pretreated with escapable aversive tones and a control group which passively

Robert J. Gatchel; Janet D. Proctor

1976-01-01

361

Lipid-Based Passivation in Nanofluidics  

PubMed Central

Stretching DNA in nanochannels is a useful tool for direct, visual studies of genomic DNA at the single molecule level. To facilitate the study of the interaction of linear DNA with proteins in nanochannels, we have implemented a highly effective passivation scheme based on lipid bilayers. We demonstrate virtually complete long-term passivation of nanochannel surfaces to a range of relevant reagents, including streptavidin-coated quantum dots, RecA proteins, and RecA–DNA complexes. We show that the performance of the lipid bilayer is significantly better than that of standard bovine serum albumin-based passivation. Finally, we show how the passivated devices allow us to monitor single DNA cleavage events during enzymatic degradation by DNase I. We expect that our approach will open up for detailed, systematic studies of a wide range of protein–DNA interactions with high spatial and temporal resolution.

2012-01-01

362

Lipid-based passivation in nanofluidics.  

PubMed

Stretching DNA in nanochannels is a useful tool for direct, visual studies of genomic DNA at the single molecule level. To facilitate the study of the interaction of linear DNA with proteins in nanochannels, we have implemented a highly effective passivation scheme based on lipid bilayers. We demonstrate virtually complete long-term passivation of nanochannel surfaces to a range of relevant reagents, including streptavidin-coated quantum dots, RecA proteins, and RecA-DNA complexes. We show that the performance of the lipid bilayer is significantly better than that of standard bovine serum albumin-based passivation. Finally, we show how the passivated devices allow us to monitor single DNA cleavage events during enzymatic degradation by DNase I. We expect that our approach will open up for detailed, systematic studies of a wide range of protein-DNA interactions with high spatial and temporal resolution. PMID:22432814

Persson, Fredrik; Fritzsche, Joachim; Mir, Kalim U; Modesti, Mauro; Westerlund, Fredrik; Tegenfeldt, Jonas O

2012-04-06

363

Passive alignment of second generation optoelectronic devices  

Microsoft Academic Search

This paper details how expanded-mode semiconductor devices and passive alignment techniques can be used to realize low-cost high-performance fiber grating laser and laser amplifier packages for future generations of optical telecommunication systems

John V. Collins; I. F. Lealman; A. Kelly; C. W. Ford

1997-01-01

364

Passive Limitations for a Magnetic Gravity Compensator  

NASA Astrophysics Data System (ADS)

The development of sophisticated advanced vibration isolation is important because even the minutest vibrations have disastrous effects on the performance of static and moving parts in high-precision machines. This paper concerns with the isolation of these vibrations for a large static body in an advanced micro-lithographic system, where a passive/active electromagnetic solution is presented. In these configurations passive permanent magnets (PM) provide the gravity compensation and active electromagnets the accurate positioning. This paper only considers the applicability of a passive magnetic solution for this high force gravity compensation application, or, more specifically, the influence of various PM array topologies on the force density. Further, fast-solving analytical models are presented and consequently are used to illustrate the feasibility of using passive permanent magnets for gravity compensation in this demanding high precision industrial application.

Janssen, Jeroen L. G.; Paulides, Johannes J. H.; Lomonova, Elena A.

365

Anomalous Scaling of the Passive Scalar.  

National Technical Information Service (NTIS)

The authors establish anomalous inertial range scaling of the structure functions for a model of homogeneous, isotropic advection of a passive scalar by a random velocity field. The velocity statistics is taken gaussian with decorrelation in time and velo...

K. Gawedzki A. Kupiainen

1995-01-01

366

Post Marketing Surveillance: Passive and Active Approaches ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... system for passive surveillance of adverse events after vaccination established in 1990 in response to the National Childhood Vaccine Injury Act of ... More results from www.fda.gov/downloads/biologicsbloodvaccines/newsevents

367

Passive imaging with pulsed ultrasound insonations  

PubMed Central

Previously, passive cavitation imaging has been described in the context of continuous-wave high-intensity focused ultrasound thermal ablation. However, the technique has potential use as a feedback mechanism for pulsed-wave therapies, such as ultrasound-mediated drug delivery. In this paper, results of experiments and simulations are reported to demonstrate the feasibility of passive cavitation imaging using pulsed ultrasound insonations and how the images depend on pulsed ultrasound parameters. The passive cavitation images were formed from channel data that was beamformed in the frequency domain. Experiments were performed in an invitro flow phantom with an experimental echo contrast agent, echogenic liposomes, as cavitation nuclei. It was found that the pulse duration and envelope have minimal impact on the image resolution achieved. The passive cavitation image amplitude scales linearly with the cavitation emission energy. Cavitation images for both stable and inertial cavitation can be obtained from the same received data set.

Haworth, Kevin J.; Mast, T. Douglas; Radhakrishnan, Kirthi; Burgess, Mark T.; Kopechek, Jonathan A.; Huang, Shao-Ling; McPherson, David D.; Holland, Christy K.

2012-01-01

368

Passive Treatment Systems for Acid Mine Drainage.  

National Technical Information Service (NTIS)

There are many types of water treatment systems available for removing metals from acid mine drainage. Passive treatment systems are a relatively new technology that involves using sulfate-reducing bacteria or limestone or both to neutralize acidity and p...

K. L. Ford

2003-01-01

369

A Microfluidic Passive Pumping Coulter Counter  

PubMed Central

A microfluidic device using on-chip passive pumping was characterized for use as a particle counter. Flow occurred due to a Young-Laplace pressure gradient between two 1.2 mm diameter inlets and a 4 mm diameter reservoir when 0.5? L fluid droplets were applied to the inlets using a micropipette. Polystyrene particles (10?m diameter) were enumerated using the resistive pulse technique. Particle counts using passive pumping were within 13% of counts from a device using syringe pumping. All pumping methods produced particle counts that were within 16% of those obtained with a hemocytometer. The effect of intermediate wash steps on particle counts within the passive pumping device was determined. Zero, one, or two wash droplets were loaded after the first of two sample droplets. No statistical difference was detected in the mean particle counts among the loading patterns (p > 0.05). Hydrodynamic focusing using passive pumping was also demonstrated.

McPherson, Amy L.; Walker, Glenn M.

2013-01-01

370

Design of PCM Enhanced Passive Solar Structures.  

National Technical Information Service (NTIS)

A design methodology for a passive solar structure using phase change materials for thermal storage is presented. The discussion focuses on the use of PCM's, charged by direct illumination of the sun. The interaction and importance of design elements are ...

J. B. Drake G. A. Geist M. D. Morris A. D. Solomon J. F. Martin

1987-01-01

371

Polarimetric Passive Remote Sensing of Ocean Surface.  

National Technical Information Service (NTIS)

In the microwave remote sensing of ocean surface, the use of polarimetric passive techniques has shown potential for enhancing the retrieval of wind speed and directions. Recent theoretical and experimental research activities have concentrated on studies...

J. Kong

2000-01-01

372

PASSIVE MICROWAVE REMOTE SENSING FOR LAND APPLILCATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Passive microwave remote sensing has made major contributions in atmospheric and oceanic sciences. These applications have exploited higher frequencies and used low frequencies to establish background conditions. Land applications have been hampered by the availability of low frequency observations...

373

Method and structure for passivating semiconductor material  

DOEpatents

A structure for passivating semiconductor material comprises a substrate of crystalline semiconductor material, a relatively thin film of carbon disposed on a surface of the crystalline material, and a layer of hydrogenated amorphous silicon deposited on the carbon film.

Pankove, Jacques I. (Princeton, NJ)

1981-01-01

374

Transport of passive scalars in a turbulent channel flow  

NASA Astrophysics Data System (ADS)

A direct numerical simulation of a turbulent channel flow with three passive scalars at different molecular Prandtl numbers is performed. Computed statistics including the turbulent Prandtl numbers are compared with existing experimental data. The computed fields are also examined to investigate the spatial structure of the scalar fields. The scalar fields are highly correlated with the streamwise velocity; the correlation coefficient between the temperature and the streamwise velocity is as high as 0.95 in the wall region. The joint probability distributions between the temperature and velocity fluctuations are also examined; they suggest that it might be possible to model the scalar fluxes in the wall region in a manner similar to the Reynolds stresses.

Kim, John; Moin, Parviz

1987-07-01

375

Transport of passive scalars in a turbulent channel flow  

NASA Astrophysics Data System (ADS)

A direct numerical simulation of a turbulent channel flow with three passive scalars at different molecular Prandtl numbers is performed. Computed statistics including the turbulent Prandtl numbers are compared with existing experimental data. The computed fields are also examined to investigate the spatial structure of the scalar fields. The scalar fields are highly correlated with the streamwise velocity; the correlation coefficient between the temperature and the streamwise velocity is as high as 0.95 in the wall region. The joint probability distributions between the temperature and velocity fluctuations are also examined; they suggest that it might be possible to model the scalar fluxes in the wall region in a manner similar to the Reynolds stresses.

Kim, John; Moin, Parviz

376

Energy savings obtainable through passive solar techniques  

SciTech Connect

A passive solar energy system is one in which the thermal energy flow is by natural means, that is by radiation, conduction, or natural convection. The purpose of the paper is to provide a survey of passive solar heating experience, especially in the US. Design approaches are reviewed and examples shown. Misconceptions are discussed. Advantages are listed. The Los Alamos program of performance simulation and evaluation is described and a simplified method of performance estimation is outlined.

Balcomb, J.D.

1980-01-01

377

Passivity enforcement via perturbation of Hamiltonian matrices  

Microsoft Academic Search

This paper presents a new technique for the passivity enforcement of linear time-invariant multiport systems in state-space form. This technique is based on a study of the spectral properties of related Hamiltonian matrices. The formulation is applicable in case the system input-output transfer function is in admittance, impedance, hybrid, or scattering form. A standard test for passivity is first performed

S. Grivet-Talocia

2004-01-01

378

Digital audiobook: from passive to active pursuit  

Microsoft Academic Search

The digital home entertainment market is growing at an exceptional speed and, although limited to passive listeners, audiobook\\u000a applications are growing at an annual rate of nearly 20% and hence are playing an important role inside this market. In this\\u000a paper we propose an architecture to produce interactive audiobooks, so as to transform a passive listener into a story director.

Marco Furini

2008-01-01

379

Passive Testing - A Constrained Invariant Checking Approach  

Microsoft Academic Search

\\u000a Passive testing of a network protocol is the process of detecting faults in the protocol implementation by passively observing\\u000a its input\\/output behaviors (execution trace) without interrupting the normal network operations. In observing the trace, we\\u000a can focus on the most expected relevant properties of the protocol specification by defining some invariants on the specification\\u000a and checking them on the trace.

Behrouz Tork Ladani; Baptiste Alcalde; Ana R. Cavalli

2005-01-01

380

Semi-passive replication and Lazy Consensus  

Microsoft Academic Search

Abstract This paper presents two main,contributions: semi-passive replication and Lazy Consensus. The former is a replication technique with parsimonious,processing. It is based on the latter; a variant of Consensus allowing the lazy evaluation of proposed,values. Semi-passive replication is a replication technique with parsimonious processing. This means that, in the normal case, each request is processed by only one single process.

Xavier Défago; André Schiper

2004-01-01

381

Antimony Passivation of InP  

Microsoft Academic Search

Antimony passivation of InP was investigated. Sb was evaporated on a HCl-etched InP substrate and annealed at 300°C for 10 min. I--V characteristics of the Au\\/Sb\\/InP diode are substantially improved and the Schottky barrier height becomes higher as compared with the conventional Au\\/InP diode. The reverse current decreases by about two orders of magnitude upon Sb passivation. X-ray photoelectron spectroscopic

Hajime Nobusawa; Hideaki Ikoma

1993-01-01

382

PRIMA: passive reduced-order interconnect macromodeling algorithm  

Microsoft Academic Search

This paper describes PRIMA, an algorithm for generating provably passive reduced order N-port models for RLC interconnect circuits. It is demonstrated that, in addition to requiring macromodel stability, macromodel passivity is needed to guarantee the overall circuit stability once the active and passive driver\\/load models are connected. PRIMA extends the block Arnoldi technique to include guaranteed passivity. Moreover, it is

Altan Odabasioglu; Mustafa Celik; Lawrence T. Pileggi

1997-01-01

383

Si/Ge heterostructure on sulphur passivated GaAs(110)  

SciTech Connect

The structure and interface state density of thin Si and Si/Ge heterolayers on sulphur passivated GaAs (110) were studied by capacitance{endash}voltage measurements, x-ray scattering, and x-ray absorption with synchrotron radiation. The results show that the reduction of interfacial state density by utilizing Si or Si/Ge thin heterolayers on sulphur passivated GaAs (110) correlates better with the short-range electronic structure at the interface than the commonly believed long-range atomic abruptness. {copyright} {ital 1997 American Institute of Physics.}

Huang, L.J.; Rajesh, K.; Lau, W.M. [Department of Materials Engineering, University of Western Ontario, London, N6A 5B9 (CANADA); Wu, X.Z. [Physics Department, Northern Illinois University, DeKalb, IL 60115 (United States)]|[Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Landheer, D.; Baribeau, J. [National Research Council of Canada, Ottawa, O1R 1C7 (CANADA); Ingrey, S. [Bell Northern Research, Ottawa, K1Y 4H7 (CANADA)

1997-07-01

384

Burgers turbulence and passive random advection  

NASA Astrophysics Data System (ADS)

The thesis is devoted to development of new methods in the theory of strong turbulence. These methods are illustrated with the so-called Burgers' model of turbulence, i.e., the Navier-Stokes equation without pressure, supplemented by a Gaussian, short-time correlated external force. The main goal of the theory is to describe the statistics of the velocity field. Since the Navier-Stokes equation is nonlinear, the problem is highly nontrivial; it is sometimes referred to as the ``Ising model'' of strong turbulence. The importance of the problem for plasma physics, astrophysics, physics of self-organized criticality, disordered systems, etc., is discussed in Chapter 1. In this thesis a new self-consistent theoretical approach to the problem is developed. The problem is treated from the field-theoretical point of view, and, therefore, appropriate methods such as regularization, operator product expansion, and an assumption about scaling invariance are employed. The scheme ``from particular to general'' is adopted. The main ideas of the approach are first developed in detail for the one-dimensional Burgers model in Chapter 2 and then generalized to the multidimensional case in Chapter 3. In all of the cases the velocity- difference and velocity-gradient probability density functions are obtained. Their derivation is based on the self-consistent conjecture about the operator product expansion for the dissipative term, introduced by Polyakov [1995]. Comparison of the obtained results with the available direct numerical simulations shows a very good agreement. The practically important longitudinal velocity-difference PDF and div v PDF in the multidimensional case are discussed within the approach. In Chapter 4 the statistics of passive quantities (such as temperature, concentration, magnetic field) ``frozen'' into the turbulent fluid are obtained by using the methods developed in Chapters 2 and 3. The velocity field is assumed to be Gaussian, and short-time correlated, and the diffusivity is neglected. These considerations illustrate that even with simple statistics of the velocity field, the statistics of advected quantities are nontrivial due to nonlinear interactions of different spatial directions. The last Chapter 5 summarizes the results and discusses future directions of research.

Boldyrev, Stanislav Anatolievich

1999-10-01

385

PS3-13: Re-Identification Risk Associated with Sharing Linked Genomic and Phenotypic Data from the Kaiser Permanente Research Program on Genes, Environment and Health (RPGEH).  

PubMed

Background/Aims It is now understood that conventional de-identification methods such as the HIPAA Safe Harbor standard do not guarantee anonymity of patient records, which may be vulnerable to a variety of attacks aimed at re-identifying confidential information. We present an analytic framework for evaluating these risks quantitatively in order to be able to explicitly balance privacy and scientific utility. As a concrete example, we examine implications for patient privacy of plans to deposit over 70,000 full-genome genotypes and associated clinical data in the dbGaP federally-managed data repository, as a component of a NIH-funded study conducted by the Research Program on Genes, Environment, and Health (RPGEH) at the Kaiser Permanente Northern California Division of Research (KPNC DOR). Risks are examined from multiple perspectives and risk reduction strategies discussed. Methods Two analytic approaches are described: (1) "k-anonymization", which computes risk based only on the distribution of cell sizes in the disclosed dataset; and (2) "k-map" which takes account of the characteristics of potential reference datasets - e.g., voter rolls, disease registries - which may be available to the attacker. Probabilities of re-identification were computed using a random sample of records from actual study participants, and assumed disclosure of the following phenotypic attributes: 5-year age group, sex, race (5 categories) and a set of 22 ICD9-defined common diseases. For method 2, the KPNC EMR was used as a proxy for a highly informative reference dataset. Results The first method tended to yield very conservative estimates of risk: 9.5% of subjects in the disclosed dataset had unique phenotypic attributes, while 18% were in cells of size <5 and 24% were in cells of size <10. Factoring in characteristics of potential reference datasets, method 2, yielded substantially lower levels of risk: 2% of subjects were distinct, 4% in cells size <5, and 6% in cells of size <10. Conclusions Assessment of re-identification risk of disclosed genomic-phenotypic data is complex, involving differing stakeholders' perspectives, attack types, and characteristics of both the disclosed data and the surrounding information environment. However, reasonable assumptions can be made which allow quantitative estimates of risk, and suggest strategies for risk reduction. PMID:24085938

Walter, Lawrence; Sciortino, Stan; Ranatunga, Dilrini; Kay, Julia; Ludwig, Dana; Somkin, Carol; Henderson, Mary; Schaefer, Cathy

2013-09-01

386

PS3-13: Re-Identification Risk Associated with Sharing Linked Genomic and Phenotypic Data from the Kaiser Permanente Research Program on Genes, Environment and Health (RPGEH)  

PubMed Central

Background/Aims It is now understood that conventional de-identification methods such as the HIPAA Safe Harbor standard do not guarantee anonymity of patient records, which may be vulnerable to a variety of attacks aimed at re-identifying confidential information. We present an analytic framework for evaluating these risks quantitatively in order to be able to explicitly balance privacy and scientific utility. As a concrete example, we examine implications for patient privacy of plans to deposit over 70,000 full-genome genotypes and associated clinical data in the dbGaP federally-managed data repository, as a component of a NIH-funded study conducted by the Research Program on Genes, Environment, and Health (RPGEH) at the Kaiser Permanente Northern California Division of Research (KPNC DOR). Risks are examined from multiple perspectives and risk reduction strategies discussed. Methods Two analytic approaches are described: (1) “k-anonymization”, which computes risk based only on the distribution of cell sizes in the disclosed dataset; and (2) “k-map” which takes account of the characteristics of potential reference datasets – e.g., voter rolls, disease registries - which may be available to the attacker. Probabilities of re-identification were computed using a random sample of records from actual study participants, and assumed disclosure of the following phenotypic attributes: 5-year age group, sex, race (5 categories) and a set of 22 ICD9-defined common diseases. For method 2, the KPNC EMR was used as a proxy for a highly informative reference dataset. Results The first method tended to yield very conservative estimates of risk: 9.5% of subjects in the disclosed dataset had unique phenotypic attributes, while 18% were in cells of size <5 and 24% were in cells of size <10. Factoring in characteristics of potential reference datasets, method 2, yielded substantially lower levels of risk: 2% of subjects were distinct, 4% in cells size <5, and 6% in cells of size <10. Conclusions Assessment of re-identification risk of disclosed genomic-phenotypic data is complex, involving differing stakeholders’ perspectives, attack types, and characteristics of both the disclosed data and the surrounding information environment. However, reasonable assumptions can be made which allow quantitative estimates of risk, and suggest strategies for risk reduction.

Walter, Lawrence; Sciortino, Stan; Ranatunga, Dilrini; Kay, Julia; Ludwig, Dana; Somkin, Carol; Henderson, Mary; Schaefer, Cathy

2013-01-01

387

All-optical correlation-based bit-pattern recognition with reduced wavelength sensitivity using wavelength conversion  

Microsoft Academic Search

We demonstrate a method of minimizing the wavelength sensitivity of the all-optical bit-pattern recognition relying on a passive optical correlator. We accomplish all-optical 40-Gb\\/s, 8-bit pattern recognition with much reduced wavelength sensitivity by combining a wavelength converter front-end and a passive optical correlator.

I. Kang; M. Rasras; M. Dinu; L. Buhl; S. Cabot; L. Zhang; M. Cappuzzo; L. T. Gomez; Y. F. Chen; S. S. Patel; D. T. Neilson; C. R. Giles; N. Dutta; A. Piccirilli; J. Jaques

2009-01-01

388

Discreet passive explosive detection through 2-sided wave guided fluorescence  

SciTech Connect

The current invention provides a passive sampling device suitable for collecting and detecting the presence of target analytes. In particular, the passive sampling device is suitable for detecting nitro-aromatic compounds. The current invention further provides a passive sampling device reader suitable for determining the collection of target analytes. Additionally, the current invention provides methods for detecting target analytes using the passive sampling device and the passive sampling device reader.

Harper, Ross James; la Grone, Marcus; Fisher, Mark

2012-10-16

389

Passive acoustics as a monitoring tool for evaluating oyster reef restoration  

NASA Astrophysics Data System (ADS)

Oyster reefs are biodiverse communities that provide many ecological and commercial benefits. However, oyster reefs have declined around the world from human activities. Oyster reef restoration programs have begun to limit some of the decline, but the need for determining the success of a program has been problematic. Passive acoustic techniques can use naturally occurring sounds produced by organisms to assess biodiversity. Passive acoustics was utilized to compare the sounds in natural and restored oyster reefs, with special attention on snapping shrimp (Alpheus spp.) snap sounds, in the St. Lucie Estuary, Florida over a one year period. Season, estuary region, habitat and day period had an effect on sound production Passive acoustic monitoring of snapping shrimp sound production may be a useful non-destructive technique for monitoring the progress of oyster reef restoration projects once further correlations are established between environmental effects and sound production.

Zenil Becerra, Hilde P.

390

Psychopathic tendencies and mesolimbic recruitment by cues for instrumental and passively-obtained rewards  

PubMed Central

Psychopathy is a constellation of self-serving attitudes and antisocial behaviors with little regard to cost to self and others. Might this symptomatology arise in part from an exaggerated response of brain motivational circuitry to prospective rewards? We examined whether psychopathic tendencies are associated with increased recruitment of incentive neurocircuitry during anticipation of instrumental and conditioned rewards. Healthy controls completed the Psychopathic Personality Inventory (PPI), then were presented with response-contingent and passively-delivered rewards during functional MRI. PPI scores correlated negatively with reaction time to incentivized targets, but not with reaction time to non-incentivized targets. PPI scores also correlated positively with recruitment of ventral striatum and anterior cingulate cortex during reward instrumental anticipation. PPI scores also correlated with middle frontal cortex recruitment during anticipation of passively-received rewards. These data indicate that in psychiatrically-healthy controls, individuals with greater endorsement of psychopathic tendencies show more robust neurophysiological and behavioral signatures of incentive motivation.

Bjork, James M.; Chen, Gang; Hommer, Daniel W.

2012-01-01

391

Active and passive mechanisms of helicases.  

PubMed

In this work, we discuss the active or passive character of helicases. In the past years, several studies have used the theoretical framework proposed by Betterton and Julicher [Betterton, M.D. and Julicher, F. (2005) Opening of nucleic-acid double strands by helicases: active versus passive opening. Phys. Rev. E, 71, 11904-11911.] to analyse the unwinding data and assess the mechanism of the helicase under study (active versus passive). However, this procedure has given rise to apparently contradictory interpretations: helicases exhibiting similar behaviour have been classified as both active and passive enzymes [Johnson, D.S., Bai, L. Smith, B.Y., Patel, S.S. and Wang, M.D. (2007) Single-molecule studies reveal dynamics of DNA unwinding by the ring-shaped T7 helicase. Cell, 129, 1299-1309; Lionnet, T., Spiering, M.M., Benkovic, S.J., Bensimon, D. and Croquette, V. (2007) Real-time observation of bacteriophage T4 gp41 helicase reveals an unwinding mechanism Proc. Natl Acid. Sci., 104, 19790-19795]. In this work, we show that when the helicase under study has not been previously well characterized (namely, if its step size and rate of slippage are unknown) a multi-parameter fit to the afore-mentioned model can indeed lead to contradictory interpretations. We thus propose to differentiate between active and passive helicases on the basis of the comparison between their observed translocation velocity on single-stranded nucleic acid and their unwinding rate of double-stranded nucleic acid (with various GC content and under different tensions). A threshold separating active from passive behaviour is proposed following an analysis of the reported activities of different helicases. We study and contrast the mechanism of two helicases that exemplify these two behaviours: active for the RecQ helicase and passive for the gp41 helicase. PMID:20423906

Manosas, Maria; Xi, Xu Guang; Bensimon, David; Croquette, Vincent

2010-04-27

392

Passivation of fluorinated activated charcoal  

SciTech Connect

The Molten Salt Reactor Experiment (MSRE), at the Oak Ridge National Laboratory has been shut down since 1969 when the fuel salt was drained from the core into two Hastelloy N tanks at the reactor site. In 1995, a multiyear project was launched to remediate the potentially hazardous conditions generated by the movement of fissile material and reactive gases from the storage tanks into the piping system and an auxiliary charcoal bed (ACB). The top 12 in. of the ACB is known by gamma scan and thermal analysis to contain about 2.6 kg U-233. According to the laboratory tests, a few feet of fluorinated charcoal are believed to extend beyond the uranium front. The remainder of the ACB should consist of unreacted charcoal. Fluorinated charcoal, when subjected to rapid heating, can decompose generating gaseous products. Under confined conditions, the sudden exothermic decomposition can produce high temperatures and pressures of near-explosive characteristics. Since it will be necessary to drill and tap the ACB to allow installation of piping and instrumentation for remediation and recovery activities, it is necessary to chemically convert the reactive fluorinated charcoal into a more stable material. Ammonia can be administered to the ACB as a volatile denaturing agent that results in the conversion of the C{sub x}F to carbon and ammonium fluoride, NH{sub 4}F. The charcoal laden with NH{sub 4}F can then be heated without risking any sudden decomposition. The only consequence of heating the treated material will be the volatilization of NH{sub 4}F as a mixture of NH{sub 3} and HF, which would primarily recombine as NH{sub 4}F on surfaces below 200 C. The planned scheme for the ACB denaturing is to flow diluted ammonia gas in steps of increasing NH{sub 3} concentration, 2% to 50%, followed by the injection of pure ammonia. This report summarizes the planned passivation treatment scheme to stabilize the ACB and remove the potential hazards. It also includes basic information, results of laboratory tests, thermodynamic calculations, process description, and operational parameters, and addresses safety concerns.

Del Cul, G.D.; Trowbridge, L.D.; Simmons, D.W.; Williams, D.F.; Toth, L.M.

1997-10-01

393

Passive education for active professionals: a review of the effectiveness of the passive studio  

SciTech Connect

A training program was developed for practicing architects and engineers and tested it during the Spring of 1980. The objective of the Passive Studio is to enable the participants to learn the specific needs of designing for various building types and climates and learn how to apply passive techniques in their practices. The Studio attracted over 400 professionals and was held in eight major cities around the country. A program of evaluation was used to document the effectiveness of the Passive Studio at achieving this objective. This testing and evaluation program led to improvements in the workshop and materials. Indications are that in three years firms of Studio participants will be designing passive building worth over $1 billion per year. Over eighty percent of these participants have already implemented passive design techniques in actual building designs in the first three months following the workshops.

Bremer, D.S.

1980-01-01

394

Non-local two-dimensional turbulence and Batchelor's regime for passive scalars  

NASA Astrophysics Data System (ADS)

We study small-scale two-dimensional non-local turbulence, where interaction of small scales with large vortices dominates in the small-scale dynamics, by using a semi-classical approach developed in Dyachenko, Nazarenko & Zakharov (1992), Nazarenko, Zabusky & Scheidegger (1995), Dubrulle & Nazarenko (1997) and Nazarenko, Kevlahan & Dubrulle (1999). Also, we consider a closely related problem of passive scalars in Batchelor's regime, when the Schmidt number is much greater than unity. In our approach, we do not perform any statistical averaging, and most of our results are valid for any form of the large-scale advection. A new invariant is found in this paper for passive scalars when their initial spectrum is isotropic. It is shown, analytically, numerically and using a dimensional argument, that there is a spectrum corresponding to an inverse cascade of the new invariant, which scales like k[minus sign]1 for turbulent energy and k1 for passive scalars. For passive scalars, the k1-spectrum was first found by Kraichnan (1974) in the special case of advection [delta]-correlated in time, and until now it was believed to correspond to an absolute thermodynamic equilibrium and not a cascade. We also obtain, both analytically and numerically, power-law spectra of decaying two-dimensional turbulence, k[minus sign]2, and passive scalar, k0.

Nazarenko, S.; Laval, J.-P.

2000-04-01

395

Passive-solar homes for Texas  

NASA Astrophysics Data System (ADS)

Acceptance of passive solar technologies has been slow within the conventional building trades in Texas because it is a common misconception that solar is expensive, and data on local applications is severely limited or nonexistent. It is the purpose of this solar development to move passive solar design into the mainstream of public acceptance by helping to overcome and eliminate these barriers. Specifically, the goal is to develop a set of regional climatic building standards to help guide the conventional building trade toward the utilization of soft energy systems which will reduce overall consumption at a price and convenience most Texans can afford. To meet this objective, eight sample passive design structures are presented. These designs represent state of the art regional applications of passive solar space conditioning. The methodology used in the passive solar design process included: analysis of regional climatic data; analysis of historical regional building prototypes; determination of regional climatic design priorities and assets; prototypical design models for the discretionary housing market; quantitative thermal analysis of prototypical designs; and construction drawings of building prototypes.

Garrison, M. L.

1982-06-01

396

Passive terahertz imaging for security application  

NASA Astrophysics Data System (ADS)

The passive detection is safe for passengers and operators as no radiation. Therefore, passive terahertz (THz) imaging can be applied to human body security check. Imaging in the THz band offers the unique property of being able to identify object through a range of materials. Therefore passive THz imaging is meaningful for security applications. This attribute has always been of interest to both the civil and military marks with applications. We took advantage of a single THz detector and a trihedral scanning mirror to propose another passive THz beam scanning imaging method. This method overcame the deficiencies of the serious decline in image quality due to the movement of the focused mirror. We exploited a THz scanning mirror with a trihedral scanning mirror and an ellipsoidal mirror to streamline the structure of the system and increase the scanning speed. Then the passive THz beam scanning imaging system was developed based on this method. The parameters were set as follows: the best imaging distance was 1.7m, the image height was 2m, the image width was 1m, the minimum imaging time of per frame was 8s, and the minimum resolution was 4cm. We imaged humans with different objects hidden under their clothes, such as fruit knife, belt buckle, mobile phone, screwdriver, bus cards, keys and other items. All the tested stuffs could be detected and recognized from the image.

Guo, Lan-tao; Deng, Chao; Zhao, Yuan-meng; Zhang, Cun-lin

2013-08-01

397

Passive ventilation for residential air quality control  

SciTech Connect

Infiltration has long served the residential ventilation needs in North America. In Northern Europe it has been augmented by purpose-provided natural ventilation systems--so-called passive ventilation systems--to better control moisture problems in dwellings smaller than their North American counterparts and in a generally wetter climate. The growing concern for energy consumption, and the environmental impacts associated with it, has however led to tighter residential construction standards on both continents and as a result problems associated with insufficient background ventilation have surfaced. Can European passive ventilation systems be adapted for use in North American dwellings to provide general background ventilation for air quality control? This paper attempts to answer this question. The configuration, specifications and performance of the preferred European passive ventilation system--the passive stack ventilation (PSV) system--will be reviewed; innovative components and system design strategies recently developed to improve the traditional PSV system performance will be outlined; and alternative system configurations will be presented that may better serve the climatic extremes and more urban contexts of North America. While these innovative and alternative passive ventilation systems hold great promise for the future, a rational method to size the components of these systems to achieve the control and precision needed to meet the conflicting constraints of new ventilation and air tightness standards has not been forthcoming. Such a method will be introduced in this paper and an application of this method will be presented.

Axley, J.

1999-07-01

398

Contribution of passive smoking to respiratory cancer.  

PubMed Central

This article reviews data from experimental and epidemiologic studies on passive smoking and makes 12 recommendations for further study. The physicochemical nature of passive smoke, the smoke inhaled by nonsmokers, differs significantly from the mainstream smoke inhaled by the active smoker. At present, measurement of urinary cotinine appears to be the best method of assessing exposures to passive smoking. Data indicate that the greater number of lung cancers in nonsmoking women is probably related to environmental tobacco smoke. Exposures in utero and very early in life to passive smoking may be important in relationship to the subsequent development of cancer and need further consideration. The short-term effects of environmental tobacco smoke on the cardiovascular system, especially among high-risk individuals, may be of greater concern than that of cancer and requires further study. Further study of increased risks of lung cancers in relation to environmental tobacco smoke exposure requires larger collaborative studies to identify lung cancer cases among nonsmokers, better delineation of pathology, and more careful selection of controls. In addition, studies of epithelial cells or specific cytology should be undertaken to determine evidence of cellular changes in relation to environmental tobacco smoke exposure. Animal inhalation studies with passive smoke should be initiated with respect to transplacental carcinogenesis, the relationship of sidestream smoke exposure with lung cancer, the induction of tumors in the respiratory tract and other organs, and the differences in the physicochemical natures of sidestream and mainstream smoke.

Kuller, L H; Garfinkel, L; Correa, P; Haley, N; Hoffmann, D; Preston-Martin, S; Sandler, D

1986-01-01

399

Coherent optical pulse CDMA systems based on coherent correlation detection  

Microsoft Academic Search

Passive optical matched filtered detection (MFD) has been employed in many proposed optical pulse code division multiple access (CDMA) system implementations, driving the development of unipolar pseudo-orthogonal codes (incoherent). Coherent optical pulse CDMA systems based on coherent correlation detection (CCD) through homodyne correlation detection (HCD) and self-HCD directly in the optical domain is proposed. With HCD, optical sequences from a

Wei Huang; Ivan Andonovic

1999-01-01

400

Passive infrared bullet detection and tracking  

DOEpatents

An apparatus and method for passively detecting a projectile such as, for example, a bullet using a passive infrared detector. A passive infrared detector is focused onto a region in which a projectile is expected to be located. Successive images of infrared radiation in the region are recorded. Background infrared radiation present in the region is suppressed such that second successive images of infrared radiation generated by the projectile as the projectile passes through the region are produced. A projectile path calculator determines the path and other aspects of the projectile by using the second successive images of infrared radiation generated by the projectile. The present invention, in certain embodiments, also determines the origin of the path of the projectile and takes a photograph of the area surrounding the origin and/or fires at least one projectile at the area surrounding the origin of the path of the projectile.

Karr, T.J.

1994-12-31

401

Load attenuating passively adaptive wind turbine blade  

DOEpatents

A method and apparatus for improving wind turbine performance by alleviating loads and controlling the rotor. The invention employs the use of a passively adaptive blade that senses the wind velocity or rotational speed, and accordingly modifies its aerodynamic configuration. The invention exploits the load mitigation prospects of a blade that twists toward feather as it bends. The invention includes passively adaptive wind turbine rotors or blades with currently preferred power control features. The apparatus is a composite fiber horizontal axis wind-turbine blade, in which a substantial majority of fibers in the blade skin are inclined at angles of between 15 and 30 degrees to the axis of the blade, to produces passive adaptive aeroelastic tailoring (bend-twist coupling) to alleviate loading without unduly jeopardizing performance.

Veers, Paul S. (Albuquerque, NM); Lobitz, Donald W. (Albuquerque, NM)

2003-01-01

402

[Advances in passive OP-FTIR].  

PubMed

As an OP-FTIR(Open Path FTIR) technology, passive OP-FTIR not only has the advantages of OP-FTIR, but also has the ability to collect data from any direction without prior background information. This technology allows mobile, fast, man-held and stand-off detection of hazardous chemical cloud.The present paper presents some developments of passive OP-FTIR, including high altitude atmospheric pollution detection, auto-detection of toxic cloud, hot gases detection (such as the determination of major combustion products in aircraft exhausts, remote sensing of smoke plumes, and remote sensing of volcano emissions), temperature and combustion products determination (including cloud temperature determination). The present paper also gives the application of passive OP-FTIR in the military. With the development of FTIR and computer science, more and more applications of OP-FTIR to environment supervision, aviation and space flight, engine exhausts, combustion and military will be fulfilled. PMID:16395896

Zhang, Li-ming; Zhang, Lin; Li, Yan; Wang, Xiao-fei; Liu, Bing-ping; Wang, Jun-de

2005-10-01

403

Passive infrared bullet detection and tracking  

DOEpatents

An apparatus and method for passively detecting a projectile such as, for example, a bullet using a passive infrared detector. A passive infrared detector is focused onto a region in which a projectile is expected to be located. Successive images of infrared radiation in the region are recorded. Background infrared radiation present in the region is suppressed such that second successive images of infrared radiation generated by the projectile as the projectile passes through the region are produced. A projectile path calculator determines the path and other aspects of the projectile by using the second successive images of infrared radiation generated by the projectile. The present invention, in certain embodiments, also determines the origin of the path of the projectile and takes a photograph of the area surrounding the origin and/or fires at least one projectile at the area surrounding the origin of the path of the projectile. 9 figs.

Karr, T.J.

1997-01-21

404

Passive infrared bullet detection and tracking  

DOEpatents

An apparatus and method for passively detecting a projectile such as, for example, a bullet using a passive infrared detector. A passive infrared detector is focused onto a region in which a projectile is expected to be located. Successive images of infrared radiation in the region are recorded. Background infrared radiation present in the region is suppressed such that second successive images of infrared radiation generated by the projectile as the projectile passes through the region are produced. A projectile path calculator determines the path and other aspects of the projectile by using the second successive images of infrared radiation generated by the projectile. The present invention, in certain embodiments, also determines the origin of the path of the projectile and takes a photograph of the area surrounding the origin and/or fires at least one projectile at the area surrounding the origin of the path of the projectile.

Karr, Thomas J. (Alamo, CA)

1997-01-01

405

Passive Cooling System for a Vehicle  

DOEpatents

A passive cooling system for a vehicle (114) transfers heat from an overheated internal component, for example, an instrument panel (100), to an external portion (116) of the vehicle (114), for example, a side body panel (126). The passive cooling system includes one or more heat pipes (112) having an evaporator section (118) embedded in the overheated internal component and a condenser section (120) at the external portion (116) of the vehicle (114). The evaporator (118) and condenser (120) sections are in fluid communication. The passive cooling system may also include a thermally conductive film (140) for thermally connecting the evaporator sections (118) of the heat pipes (112) to each other and to the instrument panel (100).

Hendricks, T. J.; Thoensen, T.

2005-11-15

406

Passive Corrosion Behavior of Alloy 22  

SciTech Connect

Alloy 22 (NO6022) was designed to stand the most aggressive industrial applications, including both reducing and oxidizing acids. Even in the most aggressive environments, if the temperature is lower than 150 F (66 C) Alloy 22 would remain in the passive state having particularly low corrosion rates. In multi-ionic solutions that may simulate the behavior of concentrated ground water, even at near boiling temperatures, the corrosion rate of Alloy 22 is only a few nano-meters per year because the alloy is in the complete passive state. The corrosion rate of passive Alloy 22 decreases as the time increases. Immersion corrosion testing also show that the newer generation of Ni-Cr-Mo alloys may offer a better corrosion resistance than Alloy 22 only in some highly aggressive conditions such as in hot acids.

R.B. Rebak; J.H. Payer

2006-01-20

407

A passive sampler for atmospheric ozone  

SciTech Connect

A simple, cost-effective passive sampler has been developed for the determination of atmospheric ozone. This passive sampler is based on a colorant which fades upon reaction with ozone, whose concentration can be determined by reflectance measurement of the color change. Direct, on-site measurements are possible, and no chemical analyses are needed. Sampler design and validation studies have been carried out and included quantitative determination of color change vs exposure time (1-8 days), color change vs. ozone concentration (30-350 ppb), and response to changes in sampler configuration that modify the passive sampling rate. With indigo carmine as the colorant, the detection limits are 30 ppb. day and 120 ppb. day using a plastic grid and Teflon filter, respectively, as diffusion barriers. Interferences from nitrogen dioxide, formaldehyde and peroxyacetyl nitrate are 15, 4 and 16%, respectively, thus resulting in a negligible bias when measuring ozone in ambient air.

Grosjean, D.; Hisham, M.W.M. (DGA, Inc., Ventura, CA (United States))

1992-02-01

408

Qualification of a passive catalytic module for hydrogen mitigation  

SciTech Connect

The advantage of passive catalytic modules for hydrogen mitigation during core-melt accidents, as compared with active devices like forced-flow recombiners or ignitors, is given by the high reliability of operation and the elimination of potentially violent combustion events. An important step in the qualification of a passive catalytic module system is the determination of the total required capacity and its distribution at various locations in the containment. Experiments and analytic modeling work were performed to qualify the installation of a system of catalytic modules for a large dry pressurized water reactor (PWR) containment. The operational capacity of a prototype catalytic module was determined experimentally, and a corresponding model correlation was developed and integrated into the GOTHIC containment code. This modified code was validated against experimental data. As an application, predictions of the effects, resulting from backfitting a large, dry PWR containment with 50 catalytic modules, were done using the modified code. The catalytic modules keep the hydrogen concentrations below a level of 10% where violent deflagrations could be expected. Local higher concentrations near the release location are inert due to associated low oxygen and high steam concentrations. A proper distribution of the modules in the containment guarantees full mixing of the atmosphere due to natural convective currents.

Fischer, K. [Battelle Ingenieurtechnik GmbH, Eschborn (Germany)

1995-10-01

409

Hydrogen passivation of self assembled InAs quantum dots  

NASA Astrophysics Data System (ADS)

A systematic study on the hydrogen passivation of nonradiative centers in InAs quantum dot's grown on GaAs substrates is presented. The samples used in this study were grown by molecular beam epitaxy. The structures contain an InxGa1-xAs insertion layer between the InAs quantum dots layer and the GaAs cap layer. The thickness and In concentration of the InxGa1-xAs are varied to achieve the emission wavelength at 1.3 ?m. The samples after the H2 plasma treatment show a significant increase of the photoluminescence intensity. The experimental results show that the quality of the InAs quantum dot structures does not degrade after the hydrogen (H2) plasma treatments. The enhancement of the photoluminescence intensity from the InAs quantum dots is thought to be due to the passivation of nonradiative centers like defects in the structures. High resolution x-ray diffraction rocking curves are used to correlate photoluminescence results.

Jacob, A. P.; Zhao, Q. X.; Willander, M.; Ferdos, F.; Sadeghi, M.; Wang, S. M.

2002-12-01

410

Passive structural health monitoring of a high-speed naval ship from ambient vibrations.  

PubMed

Previous studies have used the cross-correlation of ambient vibrations (CAV) technique to estimate the impulse response (or Green's function) between passive sensors for passive imaging purposes in various engineering applications. The technique (CAV) relies on extracting deterministic coherent time signatures from the noise cross-correlation function computed between passive sensors, without the use of controlled active sources. Provided that the ambient structure-borne noise field remains stable, these resulting coherent waveforms obtained from CAV can then be used for structural monitoring even if they differ from the actual impulse response between the passive sensors. This article presents experimental CAV results using low-frequency random vibration data (<50 Hz) collected on an all-aluminum naval vessel (the HSV-2 Swift) operating at high speed (up to 40 knots) during high sea states. The primary excitation sources were strong wave impact loadings and rotating machinery vibrations. The consistency of the CAV results is established by extracting similar coherent arrivals from ambient vibrations between the pairs of strain gages, symmetrically located across the ship's centerline. The influence of the ship's operating conditions on the stability of the peak coherent arrival time, during the 7 days trial, is also discussed. PMID:21568402

Sabra, Karim G; Huston, Steven

2011-05-01

411

Passive margin earthquakes: Reviewing knowledge and challenges  

NASA Astrophysics Data System (ADS)

Earthquakes like the August 2011 magnitude 5.8 Mineral, Va., temblor that occur on “passive” continental margins surprise people because they expect earthquakes to occur only on plate boundaries. But, in fact, large and damaging intraplate earthquakes occur fairly regularly on passive margins around the world. For instance, in North America the magnitude ˜7 Charleston earthquake shook South Carolina in 1886, causing severe damage and about 60 deaths, and the 1929 magnitude 7.2 earthquake on the Grand Banks of Newfoundland caused a tsunami, a large landslide, and 28 fatalities. Although they are fairly common, these earthquakes are not well studied, and their specific geologic settings and causes are unclear.

Balcerak, Ernie

2012-03-01

412

Passive coherent phasing of fiber laser arrays  

NASA Astrophysics Data System (ADS)

Theoretical and numerical analyses are presented of the passive coherent phasing of an array of fiber lasers that are combined in a single laser cavity by an Nx1 coupler. In an initial linear analysis it is found that the brightness gain of the passive coherent array grows linearly for a small number of fibers, however, for practical parameters, the coherent brightness gain saturates at ~ 8 - 12 for large arrays. An intensity dependent index (Kerr) nonlinearity is then introduced and it is shown that the expected maximum improvement is modest, with the coherent brightness gain saturating at 10 - 14, depending on the strength of the nonlinearity. These results are compared with recent experiments.

Rothenberg, Joshua E.

2008-03-01

413

Distant synchronization through a passive medium  

NASA Astrophysics Data System (ADS)

This paper deals with the phenomenon of synchronization of oscillatory ensembles interacting distantly through the passive medium. Main characteristics of such a kind of synchronization are studied. The results of this work can be applied to describe the synchronization of cardiac oscillatory cells separated by the passive fibroblasts. In this work the phenomenological models (Bonhoeffer-Van der Pol) of cardiac cells as well as biologically relevant (Luo-Rudy, Sachse) models are used. We also propose equivalent model of distant synchronization and derive on its basis an analytical scaling of the frequency of synchronous oscillations.

Petrov, V. S.; Osipov, G. V.; Kurths, J.

2010-08-01

414

Effect of alloying elements on passivity and breakdown of passivity of Fe- and Ni-based alloys mechanistics aspects  

SciTech Connect

On the basis of the literature data and the current results, the mechanism of pitting corrosion of Al-alloys is proposed. An assumption is made that the transport of Cl- ions through defects in the passive film of aluminum an aluminum alloys is not a rate determining step in pitting. The pit development is controlled by the solubility of the oxidized alloying elements in acid solutions. A very good correlation was found between the pitting potential and the oxidized alloying elements for metastable Al-Cr, Al-Zr, Al-W, and Al-Zn alloys. We expect that the effect of oxidized alloying elements in other passive alloys will be the same as in Al-alloys. To verify this hypothesis, susceptibility to pitting in the function of alloying elements in the binary alloys and the composition of the oxide film has to be measured. We propose studying Fe- and Ni-alloys produced by a sputtering deposition method. Using this method one-phaseous alloy can be obtained, even when the two metals are immiscible using conventional methods. Another advantage to studying sputtered alloys is to find new materials with superior resistance to localized corrosion.

Szklarska-Amialowska, Z.

1992-06-01

415

Passive solar design handbook. Volume 2 of two volumes: Passive solar design  

NASA Astrophysics Data System (ADS)

A manual for the design and performance evaluation and analysis of passive solar heating systems is presented. Two passive solar building types are analyzed: direct gain and thermal storage walls. Rules of thumb for the schematic design phase and simpified procedure for the design development phase are described. Analysis methods for the construction documents phase are given. The design procedure for fan-forced rock beds for hybrid systems is presented. Economic analysis methods for passive solar buildings are described. Tables of monthly average solar radiation, temperature and degree days for various locations in the US and southern Canada are included.

Balcomb, J. D.; Barley, D.; McFarland, R.; Perry, J., Jr.; Wray, W. O.; Noll, S.

1980-01-01

416

Passive Seismic Reflectivity Imaging with Ocean-Bottom Cable Data  

NASA Astrophysics Data System (ADS)

The idea of imaging the subsurface reflectivity distribution by correlating long traces of seismic ``noise'' (i.e. seismic data recorded without active sources) goes back more than 30 years [1]. To this day, passive seismic reflectivity imaging has not been exploited for business use in the E&P industry. The conditions for successful passive seismic reflection imaging have greatly improved over the past few years, and the prize of cheap continuous sourceless seismic imaging and possibly monitoring is still large. Nearly unlimited quantities of very high quality passive noise data are now available from permanent 4C ocean bottom cable (OBC) installations. In the present contribution, we report our initial results for single-line (2D) OBC data collected in the North Sea and GOM. The OBCs used for the experiment are of length 6-10 km with 4C receivers spaced 50 m apart. They are deployed in both shallow and deep water over large hydrocarbon reservoirs. Passive noise data were recorded for 8-24 h periods, sometimes several times, and months apart. In the analysis presented here only the hydrophone records are used, and the data from all recording periods are used together to produce a single 2D migrated reflectivity section. We observe that environmental noise (e.g. boat and rig activity) play an important role for imaging and usually requires pre-migration seismic processing steps to filter out unwanted signals. At the core of our image generation and processing sequence is the crosscorrelation of noise trace pairs and subsequent prestack time migration [1] with a velocity model established for the active-source OBC data processing. We compute 4 sec of lag time to either side of t=0. After removing unwanted signals (e.g. seafloor interface waves) from these ``virtual shot gathers'' one can clearly detect the linear-moveout direct water wave with velocity 1500 m/s, and a linear interface wave with velocity 2000 m/s. Other ``events'' with moveout are visible, but the gather is contaminated with water-column multiples. These multiples must be attenuated before migration by standard techniques. In the next processing step all (``virtual'') shot-receiver traces are migrated to obtain a subsurface image. We can clearly identify several continuous shallow events on the passive images that correspond to events known from the active source survey images. Our results, based only on a very small fraction of the available data, are thus very encouraging. No coherent events are visible below a time of about 1.5 sec, presumably still due to data paucity. We also observe that the image quality nearest very strong seafloor noise sources (rigs etc.) is very poor due to the large shear motion induced by such activity. Even in the final migrated image using input data that had water column multiples attenuated, multiples are still degrading the image quality, and we cannot distinguish primaries from multiples. It remains to be seen whether standard OBC data processing techniques like PZ summation can be used on multi-component passive data with the same beneficial effect as on active source data. More sophisticated preprocessing in conjunction with larger data volumes (2 or more OBC lines to approximate 3D coverage, and longer recording periods) and ``mining'' for particularly beneficial data are currently being pursued for image quality improvement. [1] For a review see: G. Schuster, J. Yu, J. Sheng and J. Rickett, Geophys. J. Int. 157 (2004), 838, and references therein.

Hohl, D.; Mateeva, A.

2005-12-01

417

Ocean acoustic noise and passive coherent array processing  

NASA Astrophysics Data System (ADS)

Broadband correlation processing for extracting time-domain Green's functions and coherent wavefronts from random ocean noise has been demonstrated recently using experiments and numerical simulations that are consistent with theoretical predictions. Ocean acoustic noise processing presents additional challenges over its seismological counterpart. Mainly, the ocean environment is temporally non-stationary and it is spatially heterogeneous. Further, in the lower underwater acoustic frequency regime of about 20 to 500 Hz, space-time episodic shipping is the dominant noise source. The data from different publications and research groups are gathered here, with the goal being to review recent underwater acoustic research that demonstrates the viability and potential applications of passive coherent array processing in the ocean.

Roux, Philippe; Kuperman, W. A.; Sabra, Karim G.

2011-09-01

418

Passive measurements of mixed-oxide fuel for nuclear nonproliferation  

NASA Astrophysics Data System (ADS)

We present new results on passive measurements and simulations of mixed-oxide fuel-pin assemblies. Potential tools for mixed-oxide fuel pin characterization are discussed for future nuclear-nonproliferation applications. Four EJ-309 liquid scintillation detectors coupled with an accurate pulse timing and digital, offline and optimized pulse-shape discrimination method were used. Measurement analysis included pulse-height distributions to distinguish between purely fission neutron sources and alpha-n plus fission neutrons sources. Time-dependent cross-correlation functions were analyzed to measure the fission neutron contribution to the measured sample's neutron source. The use of Monte Carlo particle transport code MCNPX-PoliMi is discussed in conjunction with the measurements.

Dolan, Jennifer L.; Flaska, Marek; Pozzi, Sara A.; Chichester, David L.

2013-03-01

419

Multiple quantum wells for passive ultra short laser pulse generation  

NASA Astrophysics Data System (ADS)

Solid state lasers are demanding independent control in the gain media and cavity loss to achieve ultra short laser pulses using passive mode-locking. Recently, laser mode-locking is achieved with a MBE structure with multiple quantum wells, designed to achieve two functions; Bragg mirror and changes in absorption to control the cavity dynamics. The use of an AlGaAs/AlAs Bragg mirror with a 15 nm GaAs saturable absorber used in a Cr:LiSAF tuneable laser proved to be effective to produce femtosecond pulses. The use of saturable absorbers thus far is a trial and error procedure that is changing due to the correlation with more predictive procedures.

Quintero-Torres, R.; Vázquez-Cerón, E.; Rodríguez-Rodríguez, E.; Stintz, Andreas; Diels, Jean-Claude

2005-05-01

420

Stain length passive dosimeter for monitoring of carbon monoxide  

SciTech Connect

A new passive dosimeter for the personal monitoring of CO exposure in the workplace has been developed. This new type of sampling device does not require follow-up analysis of the collected sample to determine the exposure. Rather, the time-weighted average concentration is determined directly from the length of a coloured stain which is produced instantaneously during the exposure period in a specially prepared indicator tube. The stain length is a function of both contaminant concentration and exposure time. The effects of CO concentration in the range 0.5-2.0 x TLV on the response of the dosimeter were evaluated in a dynamic exposure chamber. Data were fitted to the appropriate model equation with a correlation coefficient of 0.968. By eliminating the need for follow-up analysis, this stain-length dosimeter significantly reduces the cost of monitoring.

Gonzalez, L.A.; Sefton, M.V.

1983-07-01

421

Design of Programmable Passive Compliance Shoulder Mechanism  

Microsoft Academic Search

Design of mechanical compliance would be one of the most important technical foci in making humanoid robots really interactive with the humans. For safety insurance mechanical compliance should be developed for humanoid robots. The introduction of the passive compliance to humanoid robots has large possibility for achieving human skill by using the dynamical energy stored in the compliant members. Programmable

Masafumi OKADA' I; Yoshihiko Nakamura; Shigeki Ban

2001-01-01

422

Vulnerabilities of Passive Internet Threat Monitors  

Microsoft Academic Search

Passive Internet monitoring is a powerful tool for mea- suring and characterizing interesting network activity like worms or distributed denial of service attacks. By employing statistical analysis on the captured network traffic, Internet threat monitors gain valuable insight into the nature of Internet threats. In the past, these monitors have been successfully used not only to detect DoS at- tacks

Yoichi Shinoda; Ko Ikai; Motomu Itoh

2005-01-01

423

Intrinsically Passive Force Scaling in Haptic Interfaces  

Microsoft Academic Search

In several applications involving haptic interfaces it can be desirable to scale the interaction force perceived by the user. The most intuitive approach is to change the stiffness of the virtual environment but, unfortunately, changing the physical parameters that characterize a virtual environment is a potentially destabilizing action. In this paper we embed in the intrinsically passive haptic scheme recently

Cristian Secchi; Stefano Stramigioli; Cesare Fantuzzi

2006-01-01

424

Testing of Passive Energy Dissipation Systems  

Microsoft Academic Search

Over the period 1986 to 1991, seven different passive energy dissipation systems were studied in experimental research programs at the Earthquake Engineering Research Center of the University of California at Berkeley. This paper presents an overview of these studies, describing the different types of devices, the results of the shake table experiments, and associated analytical work. Four of the systems

Ian D. Aiken; Douglas K. Nims; Andrew S. Whittaker; James M. Kelly

1993-01-01

425

General Corrosion and Passive Film Stability  

Microsoft Academic Search

This report summarizes both general corrosion of Alloy 22 from 60 to 220 C and the stability of the passive (oxide) film from 60 to 90 C over a range of solution compositions that are relevant to the in-drift chemical environment at the waste package surface. The general corrosion rates were determined by weight-loss measurements in a range of complex

C Orme; J Gray; J Hayes; L Wong; R Rebak; S Carroll; J Harper; G Gdowski

2005-01-01

426

Passive vibration isolation using a Roberts linkage  

Microsoft Academic Search

The article present an ultralow frequency passive vibration isolation device as part of the preisolation stage for the Australian International Gravitational Observatory (AIGO). This isolator is based on the Roberts linkage and simulates a very long radius conical pendulum to provide two-dimensional isolation. It is designed as the second horizontal isolation component of the preisolator and it will support the

F. Garoi; J. Winterflood; L. Ju; J. Jacob; D. G. Blair

2003-01-01

427

Passive Vibration-Cancelling Isolation Mount.  

National Technical Information Service (NTIS)

An analysis of an idealized passive vibration-cancelling two-terminal mount with one degree of freedom at each mechanical terminal isolating a nonrigid machine from a nonrigid foundation is presented. To evaluate a vibration-cancelling (VC) mount, its eff...

A. O. Sykes

1987-01-01

428

Passive mine water treatment: the correct approach?  

Microsoft Academic Search

Passive waste water treatment technologies based on ecological principles for organic pollutants are gaining gradual acceptance in many industrial sectors in the western world. They represent a revival of the ancient stewardship of natural resources in response to the need for sustainable development. This revival has also lead to the use of wetlands for mine waste water with inorganic pollutants.

Margarete Kalin

2004-01-01

429

Airborne passive FT-IR spectrometry  

Microsoft Academic Search

Rapid airborne identification and quantification of vapor hazards is an environmentally important capability for a variety of open-air scenarios. This study demonstrates the use of a commercially available passive Fourier transform IR (FT-IR) spectrometer to detect, identify, and quantify ammonia and ethanol vapor signatures depending on the appropriate signal processing strategy. The signal- processing strategy removes the need for a

Robert T. Kroutil; Roger J. Combs; Robert B. Knapp; Gary W. Small

2002-01-01

430

Range-sensitive Bayesian passive sonar tracking  

Microsoft Academic Search

Passive sonar arrays are commonly operated under a far-field assumption in which the only observable parameter regarding target location is the direction of arrival of the target's signal. Range can be observed, but only when a target is in the near-field region of the array. In a Bayesian formulation of the problem, additional range dependence may be added to the

Bryan A. Yocom; Jason M. Aughenbaugh; Brian R. La Cour

2010-01-01

431

Rate distortion bounds on passive sonar performance  

Microsoft Academic Search

Information theory provides a novel perspective on passive sonar performance analysis. This approach begins by partitioning the search space and then considers the problem of assigning a source to the correct partition based on pressure observations from a hydrophone array. Prior work described necessary conditions for achieving arbitrarily small probability of error (Pe) as a tradeoff between signal-to-noise ratio (SNR)

Tianzhu Meng; John R. Buck

2010-01-01

432

Passive sonar signature estimation using bispectral techniques  

Microsoft Academic Search

An important task in underwater passive sonar signal processing is the determination of target signatures based on the narrow-band signal content in the received signal. To achieve good classification performance it is important to be able to separate the different sources (e.g. engine, hull and drive) present in the signature, and to determine the distinct frequency coupling pattern of each

R. K. Lennartsson; J. W. C. Robinson; L. Persson; M. J. Hinich; S. McLaughlin

2000-01-01

433

(Passive solar heating system). Final technical report  

Microsoft Academic Search

The reason for developing the Biancopanel was to determine the increase in air temperatures while passing over brass finned tubes enclosed in a solar collector. The author wanted to demonstrate that air will circulate by means of natural convection, thus, no fan being required. Passive solar panels were built into the roof between 22-in. center roof rafters. One negative result

Bianco

1985-01-01

434

Broadband digital transmission over passive optical networks  

Microsoft Academic Search

The authors propose a low-cost digital technique for broadband transport which is capable of transparently carrying distribution quality video, data, and digital audio services economically over a passive optical network. Two possible upgrade routes from unidirectional to bidirectional services are discussed, one using optical technology, the other using electrical techniques. The use of digital transmission, with its inherent scrambling abilities,

A. R. J. Cook; D. W. Faulkner; P. J. Smith

1991-01-01

435

Passive controller for flexible L-structures  

NASA Astrophysics Data System (ADS)

The initial findings of an experimental study to investigate the effectiveness of an impact damper to control the excessive transient oscillations of a flexible L-structure are presented here. Resonant L-frames such as overhanging structures for highway lights and two-link robotic manipulators are the possible applications of this passive controller.

Bailey, T.; Semercigil, S. E.

1994-05-01

436

Passive laminar flow control of crossflow vorticity  

NASA Astrophysics Data System (ADS)

A passive laminar flow crossflow vorticity control system includes an aerodynamic or hydrodynamic surface having geometric perturbations. The perturbations include peaks and valleys having a predetermined spacing and aligned approximately in a streamline direction to force the formation of crossflow vortices. This minimizes amplification and growth of the vortices, thus delaying transition to turbulence and reducing overall drag.

Holmes, Bruce J.

1990-11-01

437

How passive voice weakens your scholarly argument  

Microsoft Academic Search

Purpose – The purpose of this paper is to convey to authors that, by avoiding passive constructions in scholarly writing, academics can demonstrate a more thorough understanding of materials, thus strengthening arguments and presenting articles with clarity. Design\\/methodology\\/approach – Based on 12 years' experience in academic publishing, the author has worked directly with major scholars and global publishing houses to

Thomas Sigel

2009-01-01

438

Submerged passively-safe power plant  

DOEpatents

The invention as presented consists of a submerged passively-safe power station including a pressurized water reactor capable of generating at least 600 MW of electricity, encased in a double hull vessel, and provides fresh water by using the spent thermal energy in a multistage flash desalination process.

Herring, J. Stephen (Idaho Falls, ID)

1993-01-01

439

Submerged passively-safe power plant  

DOEpatents

The invention as presented consists of a submerged passively-safe power station including a pressurized water reactor capable of generating at least 600 MW of electricity, encased in a double hull vessel, and provides fresh water by using the spent thermal energy in a multistage flash desalination process. 8 figures.

Herring, J.S.

1993-09-21

440

Electrochemical modeling of passivation phenomena in tribocorrosion  

Microsoft Academic Search

The relationship between repassivation behavior and tribocorrosion is investigated using an iron–chromium alloy (AISI 430) in sulfuric acid as a model system. Tribocorrosion experiments were performed in a reciprocating motion apparatus under electrochemical polarization. A constant potential in the passive region was applied and the current variation during individual stroke periods was measured as a function of applied potential and

P Jemmely; S Mischler; D Landolt

2000-01-01

441

Interaction between Air Pollutants and Passive Sensitization  

Microsoft Academic Search

Although there is epidemiological evidence that an increase in allergic diseases such as asthma may be linked to air pollution, there is little experimental data to address this issue. The aim of this study was thus to investigate the interaction between passive sensitization and exposure to pollutants in human isolated airways. We have examined ( 1 ) th