These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Gene-environment correlation underlying the association between parental negativity and adolescent externalizing problems.  

PubMed

Studies of adolescent or parent-based twins suggest that gene-environment correlation (rGE) is an important mechanism underlying parent-adolescent relationships. However, information on how parents' and children's genes and environments influence correlated parent and child behaviors is needed to distinguish types of rGE. The present study used the novel Extended Children of Twins model to distinguish types of rGE underlying associations between negative parenting and adolescent (age 11-22 years) externalizing problems with a Swedish sample of 909 twin parents and their adolescent offspring and a U.S.-based sample of 405 adolescent siblings and their parents. Results suggest that evocative rGE, not passive rGE or direct environmental effects of parenting on adolescent externalizing, explains associations between maternal and paternal negativity and adolescent externalizing problems. PMID:23573986

Marceau, Kristine; Horwitz, Briana N; Narusyte, Jurgita; Ganiban, Jody M; Spotts, Erica L; Reiss, David; Neiderhiser, Jenae M

2013-01-01

2

Disentangling Gene-Environment Correlations and Interactions on Adolescent Depressive Symptoms  

ERIC Educational Resources Information Center

Background: Genetic risks for depression may be expressed through greater exposure towards environmental stressors (gene-environment correlation, rGE) and increased susceptibility to these stressors (gene-environment interaction, G x E). While these effects are often studied independently, evidence supports their co-occurrence on depression.…

Lau, Jennifer Y. F.; Eley, Thalia C.

2008-01-01

3

Gene-Environment Correlation Underlying the Association between Parental Negativity and Adolescent Externalizing Problems  

ERIC Educational Resources Information Center

Studies of adolescent or parent-based twins suggest that gene-environment correlation (rGE) is an important mechanism underlying parent-adolescent relationships. However, information on how parents' and children's genes and environments influence correlated parent "and" child behaviors is needed to distinguish types of rGE. The…

Marceau, Kristine; Horwitz, Briana N.; Narusyte, Jurgita; Ganiban, Jody M.; Spotts, Erica L.; Reiss, David; Neiderhiser, Jenae M.

2013-01-01

4

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

5

Gene-Environment Correlation and Interaction in Peer Effects on Adolescent Alcohol and Tobacco Use  

PubMed Central

Peer relationships are commonly thought to be critical for adolescent socialization, including the development of negative health behaviors such as alcohol and tobacco use. The interplay between genetic liability and peer influences on the development of adolescent alcohol and tobacco use was examined using a nationally-representative sample of adolescent sibling pairs and their best friends. Genetic factors, some of them related to an adolescent's own substance use and some of them independent of use, were associated with increased exposure to best friends with heavy substance use—a gene-environment correlation. Moreover, adolescents who were genetically liable to substance use were more vulnerable to the adverse influences of their best friends—a gene-environment interaction. PMID:18368474

Harden, K. Paige; Hill, Jennifer E.; Turkheimer, Eric; Emery, Robert E.

2010-01-01

6

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. PMID:20526230

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

7

Gene–environment interdependence  

Microsoft Academic Search

The modern understanding of genetic influences, of environmental effects, of mental disorder, and of heritabilities is noted. The practical utility of finding susceptibility genes with a very small effect is questioned. The empirical findings and implications of developmental perturbations, epigenetics, gene–environment correlations and interactions are then discussed. It is noted that the genes involved in gene–environment interactions may be concerned

Michael Rutter

2012-01-01

8

Genetic Correlation and Gene–Environment Interaction Between Alcohol Problems and Educational Level in Young Adulthood*  

PubMed Central

Objective: A lower level of education often co-occurs with alcohol problems, but factors underlying this co-occurrence are not well understood. Specifically, whether these outcomes share part of their underlying genetic influences has not been widely studied. Educational level also reflects various environmental influences that may moderate the genetic etiology of alcohol problems, but gene–environment interactions between educational attainment and alcohol problems are unknown. Method: We studied the two nonmutually exclusive possibilities of common genetic influences and gene–environment interaction between alcohol problems and low education using a population-based sample (n = 4,858) of Finnish young adult twins (Mage = 24.5 years, range: 22.8–28.6 years). Alcohol problems were assessed with the Rutgers Alcohol Problem Index and self-reported maximum number of drinks consumed in a 24-hour period. Years of education, based on completed and ongo-ing studies, represented educational level. Results: Educational level was inversely associated with alcohol problems in young adulthood, and this association was most parsimoniously explained by overlapping genetic influences. Independent of this co-occurrence, higher education was associated with increased relative importance of genetic influences on alcohol problems, whereas environmental factors had a greater effect among twins with lower education. Conclusions: Our findings suggest a complex relationship between educational level and alcohol problems in young adulthood. Lower education is related to higher levels of alcohol problems, and this co-occurrence is influenced by genetic factors affecting both phenotypes. In addition, educational level moderates the importance of genetic and environmental influences on alcohol problems, possibly reflecting differences in social-control mechanisms related to educational level. PMID:21388594

Latvala, Antti; Dick, Danielle M.; Tuulio-Henriksson, Annamari; Suvisaari, Jaana; Viken, Richard J.; Rose, Richard J.; Kaprio, Jaakko

2011-01-01

9

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

PubMed Central

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

2014-01-01

10

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

11

The heritability of personality is not always 50%: gene-environment interactions and correlations between personality and parenting.  

PubMed

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 both to 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. PMID:19012656

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

2008-12-01

12

Neural Correlates of Processing Passive Sentences  

PubMed Central

Previous research has shown that comprehension of complex sentences involving wh-movement (e.g., object-relative clauses) elicits activation in the left inferior frontal gyrus (IFG) and left posterior temporal cortex. However, relatively little is known about the neural correlates of processing passive sentences, which differ from other complex sentences in terms of representation (i.e., noun phrase (NP)-movement) and processing (i.e., the time course of syntactic reanalysis). In the present study, 27 adults (14 younger and 13 older) listened to passive and active sentences and performed a sentence-picture verification task using functional Magnetic Resonance Imaging (fMRI). Passive sentences, relative to active sentences, elicited greater activation in bilateral IFG and left temporo-occipital regions. Participant age did not significantly affect patterns of activation. Consistent with previous research, activation in left temporo-occipital cortex likely reflects thematic reanalysis processes, whereas, activation in the left IFG supports processing of complex syntax (i.e., NP-movement). Right IFG activation may reflect syntactic reanalysis processing demands associated with the sentence-picture verification task. PMID:24961525

Mack, Jennifer E.; Meltzer-Asscher, Aya; Barbieri, Elena; Thompson, Cynthia K.

2013-01-01

13

Gene-environment correlation in the development of adolescent substance abuse: selection effects of child personality and mediation via contextual risk factors.  

PubMed

We used a longitudinal twin design to examine selection effects of personality traits at age 11 on high-risk environmental contexts at age 14 and the extent to which these contexts mediated risk for substance abuse at age 17. Socialization at age 11 (willingness to follow rules and endorse conventional values) predicted exposure to contextual risk at age 14. Contextual risk partially mediated the effect of socialization on substance abuse, though socialization also had a direct effect. In contrast, boldness at age 11 (social engagement and assurance, thrill seeking, and stress resilience) also predicted substance abuse directly but was unrelated to contextual risk. There was substantial overlap in the genetic and shared environmental influences on socialization and contextual risk, and genetic risk in socialization contributed to substance abuse indirectly via increased exposure to contextual risk. This suggests that active gene-environment correlations related to individual differences in socialization contributed to an early, high-risk developmental trajectory for adolescent substance abuse. In contrast, boldness appeared to index an independent and direct genetic risk factor for adolescent substance abuse. PMID:23398757

Hicks, Brian M; Johnson, Wendy; Durbin, C Emily; Blonigen, Daniel M; Iacono, William G; McGue, Matt

2013-02-01

14

Gene-Environment Correlation in the Development of Adolescent Substance Abuse: Selection Effects of Child Personality and Mediation via Contextual Risk Factors  

PubMed Central

We used a longitudinal twin design to examine selection effects of personality traits at age 11 on high-risk environmental contexts at age 14, and the extent to which these contexts mediated risk for substance abuse at age 17. Socialization at age 11—willingness to follow rules and endorse conventional values—predicted exposure to contextual risk at age 14. Contextual risk partially mediated the effect of socialization on substance abuse, though socialization also had a direct effect. In contrast, boldness at age 11—social engagement and assurance, thrill-seeking, and stress resilience— also predicted substance abuse directly, but was unrelated to contextual risk. There was substantial overlap in the genetic and shared environmental influences on socialization and contextual risk, and genetic risk in socialization contributed to substance abuse indirectly via increased exposure to contextual risk. This suggests that active gene-environment correlations related to individual differences in socialization contributed to an early, high-risk developmental trajectory for adolescent substance abuse. In contrast, boldness appeared to index an independent and direct genetic risk factor for adolescent substance abuse. PMID:23398757

Hicks, Brian M.; Johnson, Wendy; Durbin, C. Emily; Blonigen, Daniel M.; Iacono, William G.; McGue, Matt

2012-01-01

15

Fast correlation method for passive-solar design  

SciTech Connect

A passive-solar design manual for single-family detached residences and dormitory-type buildings is being developed. The design procedure employed in the manual is a simplification of the original monthly solar load ratio (SLR) method. The new SLR correlations involve a single constant for each system. The correlation constant appears as a scale factor permitting the use of a universal performance curve for all passive systems. Furthermore, by providing location-dependent correlations between the annual solar heating fraction (SHF) and the minimum monthly SHF, we have eliminated the need to perform an SLR calculation for each month of the heating season.

Wray, W.O.; Biehl, F.A.; Kosiewicz, C.E.

1982-01-01

16

Entropy-based information gain approaches to detect and to characterize gene-gene and gene-environment interactions/correlations of complex diseases.  

PubMed

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 article, we first develop entropy-based test statistics to identify two-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 (IG) approach based on mutual information. For three-ways and higher order interactions, an interaction IG approach is used. In both cases, 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 single nucleotide polymorphisms, 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. PMID:22009792

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

2011-11-01

17

Gene-environment dependence creates spurious gene-environment interaction.  

PubMed

Gene-environment interactions have the potential to shed light on biological processes leading to disease and to improve the accuracy of epidemiological risk models. However, relatively few such interactions have yet been confirmed. In part this is because genetic markers such as tag SNPs are usually studied, rather than the causal variants themselves. Previous work has shown that this leads to substantial loss of power and increased sample size when gene and environment are independent. However, dependence between gene and environment can arise in several ways including mediation, pleiotropy, and confounding, and several examples of gene-environment interaction under gene-environment dependence have recently been published. Here we show that under gene-environment dependence, a statistical interaction can be present between a marker and environment even if there is no interaction between the causal variant and the environment. We give simple conditions under which there is no marker-environment interaction and note that they do not hold in general when there is gene-environment dependence. Furthermore, the gene-environment dependence applies to the causal variant and cannot be assessed from marker data. Gene-gene interactions are susceptible to the same problem if two causal variants are in linkage disequilibrium. In addition to existing concerns about mechanistic interpretations, we suggest further caution in reporting interactions for genetic markers. PMID:25152454

Dudbridge, Frank; Fletcher, Olivia

2014-09-01

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. PMID:23090766

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

2012-01-01

19

PASSIVE SENSOR IMAGING USING CROSS CORRELATIONS OF NOISY SIGNALS IN A SCATTERING MEDIUM  

E-print Network

PASSIVE SENSOR IMAGING USING CROSS CORRELATIONS OF NOISY SIGNALS IN A SCATTERING MEDIUM JOSSELIN's function between two passive sensors can be estimated from the cross correlation of recorded signal that the travel time can be effectively estimated when the ray joining the two sensors continues into the noise

Garnier, Josselin

20

Genes, Environments, and Behavior 2  

NSDL National Science Digital Library

In this lesson students will study how genetic research on behavior is conducted. Genes, Environment, and Behavior 2 is the second of two lessons about the field called behavioral genetics, in which scientists study the reciprocating influences of genes and environments on behavior, particularly human behavior. Genes, Environment and Behavior 2 introduces students to the various approaches scientists use to explore the interaction of genetic and environmental forces which shape behavior.An important objective of these lessons is to help students overcome the common public misperception that genes can have a direct relationship with behavior; for example, that there may be a "gene for criminality" or a "gene for religiosity." Another common misperception that can be dispelled through these lessons is that the development of an organism is determined solely by genetic factors; this is called genetic determinism. Possibly the most important value of these lessons, therefore, is that they can help students understand why such beliefs are false.These chapters are character-based and have relatively easy context. Provided are quizzes that that are administered after the short readings. These quizzes foster a discussion on each topic in behavior and genetics. Students will also perform a scavenger hunt on a scientific research article for phrases that reference research methods including: family studies, molecular studies, and brain imaging studies.

American Association for the Advancement of Science (;)

2006-04-25

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

Genes, Environments, and Behavior 1  

NSDL National Science Digital Library

Genes, Environment, and Behavior 1 is the first of two lessons about the field called behavioral genetics, in which scientists study the reciprocating influences of genes and environments on behavior, particularly human behavior. It provides students with a clear understanding of how behavior is defined by scientists and an overview of the genetic and environmental forces that interact to shape behavior.In this lesson, students are assigned reading materials from the book Behavioral Genetics: An introduction to how genes and environments interact through development to shape differences in mood, personality, and intelligence, published by AAAS and The Hastings Center. These chapters are character-based and have relatively easy context. Provided are quizzes that that are administered after the short readings. These quizzes foster a discussion on each topic in behavior and genetics. The titles of the chapters in this lesson are: 1) "What is behavioral genetics?", 2) "How do genes work within their environments?", 3) "How do environments impinge upon the genes?"

American Association for the Advancement of Science (;)

2006-04-25

23

Gene-Environment Interplay between Peer Rejection and Depressive Behavior in Children  

ERIC Educational Resources Information Center

Background: Genetic risk for depressive behavior may increase the likelihood of exposure to environmental stressors (gene-environment correlation, rGE). By the same token, exposure to environmental stressors may moderate the effect of genes on depressive behavior (gene-environment interaction, GxE). Relating these processes to a peer-related…

Brendgen, Mara; Vitaro, Frank; Boivin, Michel; Girard, Alain; Bukowski, William M.; Dionne, Ginette; Tremblay, Richard E.; Perusse, Daniel

2009-01-01

24

The Impact of Gene-Environment Dependence and Misclassification in Genetic Association Studies Incorporating Gene-Environment Interactions  

PubMed Central

The possibility of gene-environment interaction can be exploited to identify genetic variants associated with disease using a joint test of genetic main effect and gene-environment interaction. We consider how exposure misclassification and dependence between the true exposure E and the tested genetic variant G affect this joint test in absolute terms and relative to three other tests: the marginal test (G), the standard test for multiplicative gene-environment interaction (GE), and the case-only test for interaction (GE-CO). All tests can have inflated Type I error rate when E and G are correlated in the underlying population. For the GE and G-GE tests this inflation is only noticeable when the gene-environment dependence is unusually strong; the inflation can be large for the GE-CO test even for modest correlation. The joint G-GE test has greater power than the GE test generally, and greater power than the G test when there is no genetic main effect and the measurement error is small to moderate. The joint G-GE test is an attractive test for assessing genetic association when there is limited knowledge about casual mechanisms a priori, even in the presence of misclassification in environmental exposure measurement and correlation between exposure and genetic variants. PMID:19521099

Lindstrom, Sara; Yen, Yu-Chun; Spiegelman, Donna; Kraft, Peter

2009-01-01

25

Spatial dependence of passive scalar correlation functions in  

E-print Network

minimum at tii = 321 eee >>>> #12;Results, 3D-case Pair correlation function (S)aa2,a1,);( 222 2 2 R solution Chaotic flow in curved pipe linear velocity profile at scales t ^^ d ^d = Lagrangian trajectory ),0()()( ^ rr tt W= Diffusion scale /rd = Kolmogorov turbulence

Fominov, Yakov

26

Simulation of GPR passive interferometry using cross-correlation for LNAPL model monitoring application  

NASA Astrophysics Data System (ADS)

Passive interferometry technology is based on the relation between the reflection and the transmission responses of the subsurface. The transmission response can be received at surface in the presence of the ambient noise source in the subsurface with the cross-correlation (CC) or multidimensional deconvolution methods. We investigate the feasibility of electromagnetic (EM) wave passive interferometry with CC method. We design a 2-D finite-difference time domain (FDTD) algorithm to simulate the long-duration ground penetrating radar (GPR) measurements with random distribution of passive EM sources. The noise sources have random duration time, waveform and spatial distribution. We test the FDTD GPR passive interferometry code with above source characteristics and apply the method to light non-aqueous phase liquid (LNAPL) monitoring. Based on the model simulation data, by using common midpoint velocity analysis and normal move out correction to process the interferometry retrieve record, we can accurately obtain the dynamic changing characteristics of the target's permittivity. The LNAPL dynamic leakage model can be imaged as well. The synthetic results demonstrate that the GPR passive interferometry is feasible in subsurface LNAPL monitoring. Our work provides a foundation for a passive interferometry field application using GPR.

Li, Jing; Zeng, Zhaofa; Slob, Evert; Chen, Xiong; Liu, Fengshan

2014-12-01

27

NCI Gene-Environment Think-Tank  

Cancer.gov

Risk of cancer is determined by a complex interplay of genetic and environmental factors. Genome-wide association studies (GWAS) have identified hundreds of genetic variants associated with cancer. However, it remains unclear how to best incorporate gene-environment interplay into study design and analysis in order to better understand cancer etiology, or to identify public health interventions.

28

Gene-environment interplay and psychopathology: multiple varieties but real effects.  

PubMed

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 focus on variations in heritability according to environmental circumstances. Third, we discuss what is known about gene-environment correlations. Finally, we assess concepts and findings on the interaction between specific identified genes and specific measured environmental risks. In order to provide an understanding of what may be involved in gene-environment interplay, we begin our presentation with a brief historical review of prevailing views about the role of genetic and environmental factors in the causation of mental disorders, and we provide a simplified account of some of the key features of how genes 'work'. PMID:16492258

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

2006-01-01

29

Gene-Environment Research and Cancer Epidemiology  

Cancer.gov

Risk of most cancer types are determined by a complex interplay of genetic and environmental factors. Recent studies provide theoretical and empirical evidence that additional genetic and environmental factors can be identified in studies that examine gene-environment (GxE) interactions. More importantly, GxE interaction research has the potential to facilitate insights into biological mechanisms and strategies for cancer prevention and control. Despite progress, several challenges remain for performing these studies.

30

Finding gene-environment interactions for phobias  

Microsoft Academic Search

Phobias are common disorders causing a great deal of suffering. Studies of gene-environment interaction (G × E) have revealed\\u000a much about the complex processes underlying the development of various psychiatric disorders but have told us little about\\u000a phobias. This article describes what is already known about genetic and environmental influences upon phobias and suggests\\u000a how this information can be used

Alice M. Gregory; Jennifer Y. F. Lau; Thalia C. Eley

2008-01-01

31

Neuronal Correlates of a Virtual-Reality-Based Passive Sensory P300 Network  

PubMed Central

P300, a positive event-related potential (ERP) evoked at around 300 ms after stimulus, can be elicited using an active or passive oddball paradigm. Active P300 requires a person’s intentional response, whereas passive P300 does not require an intentional response. Passive P300 has been used in incommunicative patients for consciousness detection and brain computer interface. Active and passive P300 differ in amplitude, but not in latency or scalp distribution. However, no study has addressed the mechanism underlying the production of passive P300. In particular, it remains unclear whether the passive P300 shares an identical active P300 generating network architecture when no response is required. This study aims to explore the hierarchical network of passive sensory P300 production using dynamic causal modelling (DCM) for ERP and a novel virtual reality (VR)-based passive oddball paradigm. Moreover, we investigated the causal relationship of this passive P300 network and the changes in connection strength to address the possible functional roles. A classical ERP analysis was performed to verify that the proposed VR-based game can reliably elicit passive P300. The DCM results suggested that the passive and active P300 share the same parietal-frontal neural network for attentional control and, underlying the passive network, the feed-forward modulation is stronger than the feed-back one. The functional role of this forward modulation may indicate the delivery of sensory information, automatic detection of differences, and stimulus-driven attentional processes involved in performing this passive task. To our best knowledge, this is the first study to address the passive P300 network. The results of this study may provide a reference for future clinical studies on addressing the network alternations under pathological states of incommunicative patients. However, caution is required when comparing patients’ analytic results with this study. For example, the task presented here is not applicable to incommunicative patients. PMID:25401520

Chen, Chun-Chuan; Syue, Kai-Syun; Li, Kai-Chiun; Yeh, Shih-Ching

2014-01-01

32

The Role of Individual Correlates and Class Norms in Defending and Passive Bystanding Behavior in Bullying: A Multilevel Analysis  

ERIC Educational Resources Information Center

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.,…

Pozzoli, Tiziana; Gini, Gianluca; Vieno, Alessio

2012-01-01

33

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. PMID:21536163

Lotrich, Francis E.

2011-01-01

34

Information-theoretic metrics for visualizing gene-environment interactions.  

PubMed

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. PMID:17924337

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

2007-11-01

35

Coherent averaging of the passive fathometer response using short correlation time  

E-print Network

experimental data.1­3,8,9 The technique relies on surface generated noise from wind and waves.10,11 Ship- ping s and, for correlation times less than a few seconds, the observed sig- nal-to-noise ratio (SNR) agrees-correlation of ambient noise data from a drifting vertical array, has been the subject of much discussion in recent years

Gerstoft, Peter

36

The neural correlates of passively viewed sequences of true and false beliefs.  

PubMed

The ability to infer other people's mental states such as desires, emotions, intentions and beliefs is essential for successful social interactions, and it is usually referred to as theory of mind (ToM). In particular, the ability to detect and understand that people have beliefs about reality that may be false is considered an important hallmark of ToM. This experiment reports on the results of 18 participants who viewed photographic sequences of an actress performing actions as a consequence of true and false beliefs. Consistent with prior work, results from the passive viewing of stimuli depicting true belief indicated an increased response over frontal, central and parietal regions when compared with the amplitude for the false belief condition. These results show that (i) frontal activity is required for processing false belief tasks and (ii) parietal effects reported in previous studies to reflect specific cognitive process of monitoring others' beliefs can be elicited in the absence of an explicit instruction for mentalizing. PMID:22317745

Geangu, Elena; Gibson, Aimee; Kaduk, Katharina; Reid, Vincent M

2013-04-01

37

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

NASA Technical Reports Server (NTRS)

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 4) four-look combining methods 2 and 3. The systematic errors are found to depend on the polarimeter component parameters and accuracy of calibration noise temperatures. A case study radiometer in four different remote sensing scenarios was considered in light of these results. Applications for Ocean surface salinity, Ocean surface winds, and soil moisture were found to be sensitive to different systematic errors. Finally, a standard uncertainty analysis was performed on the four-look calibration algorithm, which was found to be most sensitive to the correlated calibration source.

Piepmeier, J. R.

2003-01-01

38

Gene-Environment Contributions to Young Adult Sexual Partnering  

Microsoft Academic Search

To date, there has been relatively little work on gene-environment contributions to human sexuality, especially molecular\\u000a analyses examining the potential contributions of specific polymorphisms in conjunction with life experiences. Using Wave\\u000a III data from 717 heterozygous young adult sibling pairs included in the National Longitudinal Study of Adolescent Health,\\u000a this article examined the combined contributions of attendance at religious services

Carolyn T. Halpern; Christine E. Kaestle; Guang Guo; Denise D. Hallfors

2007-01-01

39

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

40

Mouse models of gene-environment interactions in schizophrenia  

PubMed Central

Gene-environment interactions (GEI) likely play significant roles in the pathogenesis of schizophrenia and underlie differences in pathological, behavioral, and clinical presentations of the disease. Findings from epidemiology and psychiatric genetics have assisted in the generation of animal models of GEI relevant to schizophrenia. These models may provide a foundation for elucidating the molecular, cellular, and circuitry mechanisms that mediate GEI in schizophrenia. Here we critically review current mouse models of GEI related to schizophrenia, describe directions for their improvement, and propose endophenotypes provide a more tangible basis for molecular studies of pathways of GEI and facilitate the identification of novel therapeutic targets. PMID:23748077

Kannan, Geetha; Sawa, Akira; Pletnikov, Mikhail V.

2013-01-01

41

Confluence of genes, environment, development, and behavior in a post Genome-Wide Association Study world.  

PubMed

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 payoffs. 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 in the history of psychology and is informed by psychometrics, whereas the environment remains relatively poorly measured and is often confounded with genetic effects (i.e., gene-environment correlation). Genetically informed designs, which are no longer limited to twin and adoption studies thanks to ever-cheaper genotyping, are required to understand environmental influences. Finally, we outline the vast amount of individual difference in structural genomic variation, most of which remains to be leveraged in genetic association tests. Although the genetic data can be massive and burdensome (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. PMID:23062291

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

2012-11-01

42

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. PMID:23062291

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

2012-01-01

43

Passivation of HgCdTe with CdS thin films - Correlation of device characteristics with surface spectroscopy  

Microsoft Academic Search

Results are presented on the passivation of HgCdTe with thin CdS films grown anodically in nonaqueous polysulfide electrolytes. MIS capacitors were used to demonstrate good passivation layers of CdSZnS on HgCdTe. Results of depth-profiling with AES and XPS show that Hg and Te were partially incorporated into the CdS layer as undissolved HgS and TeS2. The capacitance-voltage data displayed large

John P. Ziegler; John M. Lindquist; John C. Hemminger

1989-01-01

44

Gene-Environment-Wide Association Studies: Emerging Approaches  

PubMed Central

Despite the yield of recent genome-wide association (GWA) studies, the identified variants explain only a small proportion of the heritability of most complex diseases. This unexplained heritability could be partly due to gene-environment (G×E) interactions or more complex pathways involving multiple genes and exposures. This article provides a tutorial on the available epidemiological designs and statistical analysis approaches for studying specific G×E interactions and choosing the most appropriate methods. I discuss the approaches that are being developed to study entire pathways and available techniques for mining interactions in GWA data. I also explore approaches to marrying hypothesis-driven pathway-based approaches with “agnostic” GWA studies. PMID:20212493

Thomas, Duncan

2010-01-01

45

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

2013-02-01

46

Eating disorders, gene-environment interactions and epigenetics.  

PubMed

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 have transcriptional and phenotypic effects, which, in turn, alter the long term risk of developing an eating disorder. It reviews theoretical and practical issues associated with epigenetic studies in psychiatry and how these are relevant to eating disorders. It examines the limited number of epigenetic studies which have been conducted in eating disorders and suggests directions for further research. Understanding the relationship between epigenetic processes and the risk of an eating disorder opens possibilities for preventive and/or therapeutic interventions. For example, epigenetic changes associated with diet and weight may be reversible and those associated with cognitive processes may be accessible to pharmacological interventions. PMID:20888360

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

2011-01-01

47

Study of oral clefts: Indication of gene-environment interaction  

SciTech Connect

In this study of infants with isolated birth defects, 69 cleft palate-only (CPO) cases, 114 cleft lip with or without palate (CL/P), and 284 controls with non-cleft birth defects (all born in Maryland during 1984-1992) were examined to test for associations among genetic markers and different oral clefts. Modest associations were found between transforming growth factor {alpha} (TGF{alpha}) marker and CPO, as well as that between D17S579 (Mfd188) and CL/P in this study. The association between TGF{alpha} marker and CPO reflects a statistical interaction between mother`s smoking and child`s TGF{alpha} genotype. A significantly higher risk of CPO was found among those reporting maternal smoking during pregnancy and carrying less common TGF{alpha} TaqI allele (odds ratio=7.02 with 95% confidence interval 1.8-27.6). This gene-environment interaction was also found among those who reported no family history of any type of birth defect (odds ratio=5.60 with 95% confidence interval 1.4-22.9). Similar associations were seen for CL/P, but these were not statistically significant.

Hwang, S.J.; Beaty, T.H.; Panny, S. [Johns Hopkins Univ., Baltimore, MD (United States)] [and others

1994-09-01

48

Prospects for gene-environment interactions in exfoliation syndrome.  

PubMed

Complex traits can be triggered by environmental factors in genetically predisposed individuals. The lysyl oxidase-like 1 gene (LOXL1) variants associated with exfoliation syndrome (XFS) are detected in >90% of cases that have been genotyped from sites around the world. Remarkably, roughly 80% of people without XFS also possess these same variants in all populations that have been tested. Nonetheless, the prevalence of XFS varies from ?0.4% to >20%. These data suggest that other genetic variants, epigenetic modifications, or environmental factors also contribute to XFS. Furthermore, it is possible that environmental factors modify the association between LOXL1 and XFS. Interactions between LOXL1 variants and environmental factors could explain the varying prevalence of XFS seen throughout the world. At the very least, the discovery of the association between LOXL1 variants and XFS has opened the door to the discovery of environmental risk factors for this condition. Candidate gene-environment interactions in XFS will be discussed. PMID:25275911

Pasquale, Louis R; Kang, Jae H; Wiggs, Janey L

2014-01-01

49

Passivation of HgCdTe with CdS thin films: Correlation of device characteristics with surface spectroscopy  

Microsoft Academic Search

We present results on the passivation of HgCdTe with thin films of CdS grown anodically from nonaqueous polysulfide electrolytes. Electrochemical measurements have been carried out to develop an understanding of the film growth. Capacitance-voltage measurements on metal-insulator-semiconductor (MIS) device structures that incorporated a ZnS cap and Pd gate metal over the CdS are used to compare electrical properties of the

John P. Ziegler; John M. Lindquist; John C. Hemminger

1989-01-01

50

Sleep Duration and Depressive Symptoms: A Gene-Environment Interaction  

PubMed Central

Objective: We used quantitative genetic models to assess whether sleep duration modifies genetic and environmental influences on depressive symptoms. Method: Participants were 1,788 adult twins from 894 same-sex twin pairs (192 male and 412 female monozygotic [MZ] pairs, and 81 male and 209 female dizygotic [DZ] pairs] from the University of Washington Twin Registry. Participants self-reported habitual sleep duration and depressive symptoms. Data were analyzed using quantitative genetic interaction models, which allowed the magnitude of additive genetic, shared environmental, and non-shared environmental influences on depressive symptoms to vary with sleep duration. Results: Within MZ twin pairs, the twin who reported longer sleep duration reported fewer depressive symptoms (ec = -0.17, SE = 0.06, P < 0.05). There was a significant gene × sleep duration interaction effect on depressive symptoms (a'c = 0.23, SE = 0.08, P < 0.05), with the interaction occurring on genetic influences that are common to both sleep duration and depressive symptoms. Among individuals with sleep duration within the normal range (7-8.9 h/night), the total heritability (h2) of depressive symptoms was approximately 27%. However, among individuals with sleep duration within the low (< 7 h/night) or high (? 9 h/night) range, increased genetic influence on depressive symptoms was observed, particularly at sleep duration extremes (5 h/night: h2 = 53%; 10 h/night: h2 = 49%). Conclusion: Genetic contributions to depressive symptoms increase at both short and long sleep durations. Citation: Watson NF; Harden KP; Buchwald D; Vitiello MV; Pack AI; Stachan E; Goldberg J. Sleep duration and depressive symptoms: a gene-environment interaction. SLEEP 2014;37(2):351-358. PMID:24497663

Watson, Nathaniel F.; Harden, Kathryn Paige; Buchwald, Dedra; Vitiello, Michael V.; Pack, Allan I.; Strachan, Eric; Goldberg, Jack

2014-01-01

51

Anomalous scaling of a passive scalar advected by a turbulent velocity field with finite correlation time and uniaxial small-scale anisotropy.  

PubMed

The influence of uniaxial small-scale anisotropy on the stability of the scaling regimes and on the anomalous scaling of the structure functions of a passive scalar advected by a Gaussian solenoidal velocity field with finite correlation time is investigated by the field theoretic renormalization group and operator product expansion within one-loop approximation. Possible scaling regimes are found and classified in the plane of exponents epsilon-eta , where epsilon characterizes the energy spectrum of the velocity field in the inertial range E proportional, variantk;{1-2epsilon} , and eta is related to the correlation time of the velocity field at the wave number k which is scaled as k;{-2+eta} . It is shown that the presence of anisotropy does not disturb the stability of the infrared fixed points of the renormalization group equations, which are directly related to the corresponding scaling regimes. The influence of anisotropy on the anomalous scaling of the structure functions of the passive scalar field is studied as a function of the fixed point value of the parameter u , which represents the ratio of turnover time of scalar field and velocity correlation time. It is shown that the corresponding one-loop anomalous dimensions, which are the same (universal) for all particular models with a concrete value of u in the isotropic case, are different (nonuniversal) in the case with the presence of small-scale anisotropy and they are continuous functions of the anisotropy parameters, as well as the parameter u . The dependence of the anomalous dimensions on the anisotropy parameters of two special limits of the general model, namely, the rapid-change model and the frozen velocity field model, are found when u-->infinity and u-->0 , respectively. PMID:18351933

Jurcisinová, E; Jurcisin, M

2008-01-01

52

Immune correlates of protection against yellow fever determined by passive immunization and challenge in the hamster model  

PubMed Central

Live, attenuated yellow fever (YF) 17D vaccine is highly efficacious but causes rare, serious adverse events resulting from active replication in the host and direct viral injury to vital organs. We recently reported development of a potentially safer ?-propiolactone-inactivated whole virion YF vaccine (XRX-001) which was highly immunogenic in mice, hamsters, monkeys, and humans (Vaccine 2010; 28:3827–40; New Engl J Med 2011;364:1326–33). To characterize the protective efficacy of neutralizing antibodies stimulated by the inactivated vaccine, graded doses of serum from hamsters immunized with inactivated XRX-001 or live 17D vaccine were transferred to hamsters by the intraperitoneal (IP) route 24 hours prior to virulent, viscerotropic YF virus challenge. Neutralizing antibody (PRNT50) titers were determined in the sera of treated animals 4 hours before challenge and 4 and 21 days after challenge. Neutralizing antibodies were shown to mediate protection. Animals having 50% plaque reduction neutralization test (PRNT50) titers of ?40 four hours before challenge were completely protected from disease as evidenced by viremia, liver enzyme elevation, and protection against illness (weight change) and death. Passive titers of 10–20 were partially protective. Immunization with the XRX-001 vaccine stimulated YF neutralizing antibodies that were equally effective (based on dose response) as antibodies stimulated by live 17D vaccine. The results will be useful in defining the level of seroprotection in clinical studies of new yellow fever vaccines. PMID:21718741

Julander, Justin G.; Trent, Dennis W.; Monath, Thomas P.

2011-01-01

53

Gene-Environment Interactions in Genome-Wide Association Studies: Current Approaches and New Directions  

PubMed Central

Background Complex psychiatric traits have long been thought to be the result of a combination of genetic and environmental factors, and gene-environment interactions are thought to play a crucial role in behavioral phenotypes and the susceptibility and progression of psychiatric disorders. Candidate gene studies to investigate hypothesized gene-environment interactions are now fairly common in human genetic research, and with the shift towards genome-wide association studies, genome-wide gene-environment interaction studies are beginning to emerge. Methods We summarize the basic ideas behind gene-environment interaction, and provide an overview of possible study designs and traditional analysis methods in the context of genome-wide analysis. We then discuss novel approaches beyond the traditional strategy of analyzing the interaction between the environmental factor and each polymorphism individually. Results Two-step filtering approaches that reduce the number of polymorphisms tested for interactions can substantially increase the power of genome-wide gene-environment studies. New analytical methods including data-mining approaches, and gene-level and pathway-level analyses, also have the capacity to improve our understanding of how complex genetic and environmental factors interact to influence psychological and psychiatric traits. Such methods, however, have not yet been utilized much in behavioral and mental health research. Conclusions Although methods to investigate gene-environment interactions are available, there is a need for further development and extension of these methods to identify gene-environment interactions in the context of genome-wide association studies. These novel approaches need to be applied in studies of psychology and psychiatry. PMID:23808649

Winham, Stacey J; Biernacka, Joanna M.

2013-01-01

54

Evaluation of an inactivated Ross River virus vaccine in active and passive mouse immunization models and establishment of a correlate of protection.  

PubMed

Ross River Virus has caused reported outbreaks of epidemic polyarthritis, a chronic debilitating disease associated with significant long-term morbidity in Australia and the Pacific region since the 1920s. To address this public health concern, a formalin- and UV-inactivated whole virus vaccine grown in animal protein-free cell culture was developed and tested in preclinical studies to evaluate immunogenicity and efficacy in animal models. After active immunizations, the vaccine dose-dependently induced antibodies and protected adult mice from viremia and interferon ?/? receptor knock-out (IFN-?/?R(-/-)) mice from death and disease. In passive transfer studies, administration of human vaccinee sera followed by RRV challenge protected adult mice from viremia and young mice from development of arthritic signs similar to human RRV-induced disease. Based on the good correlation between antibody titers in human sera and protection of animals, a correlate of protection was defined. This is of particular importance for the evaluation of the vaccine because of the comparatively low annual incidence of RRV disease, which renders a classical efficacy trial impractical. Antibody-dependent enhancement of infection, did not occur in mice even at low to undetectable concentrations of vaccine-induced antibodies. Also, RRV vaccine-induced antibodies were partially cross-protective against infection with a related alphavirus, Chikungunya virus, and did not enhance infection. Based on these findings, the inactivated RRV vaccine is expected to be efficacious and protect humans from RRV disease. PMID:21477673

Holzer, Georg W; Coulibaly, Sogue; Aichinger, Gerald; Savidis-Dacho, Helga; Mayrhofer, Josef; Brunner, Susanne; Schmid, Karl; Kistner, Otfried; Aaskov, John G; Falkner, Falko G; Ehrlich, Hartmut; Barrett, P Noel; Kreil, Thomas R

2011-05-31

55

Correlation  

Microsoft Academic Search

Reviews 16 publications (1913-1914) based on the problem of correlations. Correlation is viewed as a means of solving the problem of development and the traits that are affected. The uses of correlations are also discussed. A high correlation does not signify good quality of the two factors. A more intensive study of the factors influencing correlation is recommended. Cites a

James Burt Miner

1914-01-01

56

Correlation  

Microsoft Academic Search

Reviews 38 studies on statistical correlation (1913-1916). Several studies have tried to explain and investigate Spearman's theory of general and specific mental factors in terms of correlation. The interpretation of correlation through heredity has also been discussed by investigators. A number of methods such as partial and multiple correlations, variant difference correlation method, and several others have been devised. The

James Burt Miner

1916-01-01

57

Correlation  

Microsoft Academic Search

Reviews 7 studies in the area of interpretation of correlation from the psychological point of view. The limitations and meanings of correlation methods have also been given. The statistical methods of calculating correlation, as given by 8 psychologists have been reported. Presents 22 reports, given by various psychologists, who have evaluated the tests using various correlation methods. Six studies were

James Burt Miner

1919-01-01

58

Effect of gene environment interactions on lung function and cardiovascular disease in COPD  

PubMed Central

Background: The objective of this study was to determine if gene-environment interactions between cigarette smoking and interleukin-6 (IL6), interferon-? (IFNG), interleukin-1? (IL1B), or interleukin-1 receptor antagonist (IL1RN) single nucleotide polymorphisms are associated with lung function decline and cardiovascular disease in chronic obstructive pulmonary disease (COPD). Methods: Single nucleotide polymorphisms (SNPs) in IL6, IFNG, IL1B, and IL1RN were genotyped in the Lung Health Study and correlated with rate of decline of forced expiratory volume in 1 second (FEV1) over 5 years, baseline FEV1, serum protein levels, cardiovascular disease, and interactions with smoking. Results: The IL6 rs2069825 single nucleotide polymorphism was associated with the rate of decline of prebronchodilator FEV1 (P = 0.049), and was found to have a significant interaction (P = 0.004) with mean number of cigarettes smoked per day. There was also a significant interaction of IFNG rs2069727 with smoking on prebronchodilator (P = 0.008) and postbronchodilator (P =0.01) FEV1. The IL6 polymorphism was also associated with cardiovascular disease in heterozygous individuals (P = 0.044), and was found to have a significant interaction with smoking (P = 0.024). None of the genetic variants were associated with their respective serum protein levels. Conclusion: The results suggest interactions of IL6 rs2069825 and IFNG rs2069727 single nucleotide polymorphisms with cigarette smoking on measures of lung function. The IL6 rs2069825 single nucleotide polymorphism also interacted with smoking to affect the risk of cardiovascular disease in COPD patients. PMID:21814463

Hackett, Tillie-Louise; Stefanowicz, Dorota; Aminuddin, Farzian; Sin, Don D; Connett, John E; Anthonisen, Nicholas R; Pare, Peter D; Sandford, Andrew J

2011-01-01

59

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. PMID:18791076

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

2008-01-01

60

Exploiting Gene Expression Variation to Capture Gene-Environment Interactions for Disease  

PubMed Central

Gene-environment interactions have long been recognized as a fundamental concept in evolutionary, quantitative, and medical genetics. In the genomics era, study of how environment and genome interact to shape gene expression variation is relevant to understanding the genetic architecture of complex phenotypes. While genetic analysis of gene expression variation focused on main effects, little is known about the extent of interaction effects implicating regulatory variants and their consequences on transcriptional variation. Here we survey the current state of the concept of transcriptional gene-environment interactions and discuss its utility for mapping disease phenotypes in light of the insights gained from genome-wide association studies of gene expression. PMID:23755064

Idaghdour, Youssef; Awadalla, Philip

2013-01-01

61

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.; Dorai-Raj, S.; Robinson, T.

2009-09-14

62

Passive euthanasia  

Microsoft Academic Search

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

E Garrard; S Wilkinson

2005-01-01

63

Challenges in the appraisal and application of gene–environment interdependence  

Microsoft Academic Search

Recent molecular data and behavioural genetic findings add evidence in support of gene–environment interdependence. While it is clear that this new body of knowledge should influence current concepts and methods, it remains to be understood how, and in what specific circumstances, integration with existing science can be accomplished. Considerations on how to deal with some challenges arising from the appraisal

Marco Battaglia

2012-01-01

64

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

65

Gene-Environment interactions in addictive disorders: epidemiological and methodological aspects.  

E-print Network

Gene-Environment interactions in addictive disorders: epidemiological and methodological aspects. Interactions gène - environnement dans les pathologies addictives: aspects méthodologiques et épidémiologiques associated to addictive behaviors. Twin studies first help to disentangle the respective role of environment

Paris-Sud XI, Université de

66

Gene–environment interaction analysis of serotonin system markers with adolescent depression  

Microsoft Academic Search

We report analyses from a study of gene–environment interaction in adolescent depression. The sample was selected from 1990 adolescents aged 10–20 years: those with depression symptoms in the top or bottom 15% were identified and divided into high or low environmental risk groups. DNA was obtained from 377 adolescents, representing the four quadrants of high or low depression and high

T C Eley; K Sugden; A Corsico; A M Gregory; P Sham; P McGuffin; R Plomin; I W Craig

2004-01-01

67

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

68

Correlation  

Microsoft Academic Search

Reviews 32 papers on correlation its methods, interpretation and application. Highlights the contributions of K. Pearson, B. Hart and C. Spearman, and W. H. Winch. W. Betz's publications concludes that correlation alone does not demonstrate a functional connection and serves the purpose of (1) describing educational or social descriptions of Large groups, and (2) discovering functional connections when used with

James Burt Miner

1912-01-01

69

Correlation  

Microsoft Academic Search

Discusses: (1) the need for a general factor to explain the correlation between tested psychophysical processes and (2) the importance of multiple correlation in solving the complex problems. Reports the contributions of Thurstone, Ruml and Kelley to the methods of calculation of coefficients. Doll offers new ways of using corrections. Applications of this method in new fields other than applied

James Burt Miner

1917-01-01

70

Gene-Environment Interactions and Epigenetic Basis of Human Diseases 25 Horizon Scientific Press. http://www.horizonpress.com  

E-print Network

Gene-Environment Interactions and Epigenetic Basis of Human Diseases 25 © Horizon Scientific Press://www.cimb.org Gene-Environment Interactions and Epigenetic Basis of Human Diseases Liang Liu1,2*, Yuanyuan Li3 into chromatin structures, which lead to high condensations of the genes that require dynamic chromatin

71

Correlation  

Microsoft Academic Search

Examines the use of various methods of correlations, for determining the diagnostic value of tests, used in analysis of abilities, in business psychology, mental development and school records. Also reviews a number of studies done in this regard.

James Burt Miner

1918-01-01

72

Timing is critical: Gene, environment and timing interactions in genetics of suicide in children and adolescents  

Microsoft Academic Search

Suicidal behavior runs in families and is prevalent in adolescence. Case-control and family-based studies in this age group failed to find a genetic association that survived replications. Gene environment approach gave new hope for possible associations especially with the short allele of the serotonin transporter promoter polymorphism (5-HTTLPR). However, a recent meta-analysis raised doubts about the consistency of these findings.

G. Zalsman

2010-01-01

73

Using the Stepfamily Genetic Design to Examine Gene-Environment Processes in Child and Family Functioning  

Microsoft Academic Search

Studying children in different types of families-intact, single-mother, and stepparent families-affords opportunities for testing models of gene-environment processes, based on estimates of sibling similarity among full-siblings and half-siblings. We used a stepfamily quantitative genetic design to estimate genetic and environmental sources of variance in children's behavior problems and prosocial behaviors, as well as negativity in their relationships with their mothers

Kirby Deater-Deckard; Judy Dunn; Thomas G. Oconnor; Lisa Davies; Jean Golding

2003-01-01

74

Gene-Environment Interactions in Cancer Epidemiology: A National Cancer Institute Think Tank Report  

PubMed Central

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 (0.01gene-environment 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 10th–011th, 2012. The objective of the Think Tank was to facilitate discussions on: 1) the state of the science; 2) the goals of gene-environment 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 gene-environment 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; Gillander, Elizabeth M.

2014-01-01

75

Comparison of two methods for analysis of gene-environment interactions in longitudinal family data: the Framingham heart study  

PubMed Central

Gene–environment interaction (GEI) analysis can potentially enhance gene discovery for common complex traits. However, genome-wide interaction analysis is computationally intensive. Moreover, analysis of longitudinal data in families is much more challenging due to the two sources of correlations arising from longitudinal measurements and family relationships. GWIS of longitudinal family data can be a computational bottleneck. Therefore, we compared two methods for analysis of longitudinal family data: a methodologically sound but computationally demanding method using the Kronecker model (KRC) and a computationally more forgiving method using the hierarchical linear model (HLM). The KRC model uses a Kronecker product of an unstructured matrix for correlations among repeated measures (longitudinal) and a compound symmetry matrix for correlations within families at a given visit. The HLM uses an autoregressive covariance matrix for correlations among repeated measures and a random intercept for familial correlations. We compared the two methods using the longitudinal Framingham heart study (FHS) SHARe data. Specifically, we evaluated SNP–alcohol (amount of alcohol consumption) interaction effects on high density lipoprotein cholesterol (HDLC). Keeping the prohibitive computational burden of KRC in mind, we limited the analysis to chromosome 16, where preliminary cross-sectional analysis yielded some interesting results. Our first important finding was that the HLM provided very comparable results but was remarkably faster than the KRC, making HLM the method of choice. Our second finding was that longitudinal analysis provided smaller P-values, thus leading to more significant results, than cross-sectional analysis. This was particularly pronounced in identifying GEIs. We conclude that longitudinal analysis of GEIs is more powerful and that the HLM method is an optimal method of choice as compared to the computationally (prohibitively) intensive KRC method. PMID:24523728

Sung, Yun Ju; Simino, Jeannette; Kume, Rezart; Basson, Jacob; Schwander, Karen; Rao, D. C.

2014-01-01

76

Combining disease models to test for gene-environment interaction in nuclear families.  

PubMed

It is useful to have robust gene-environment interaction tests that can utilize a variety of family structures in an efficient way. This article 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. PMID:21401569

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

2011-12-01

77

Integrative analysis of gene-environment interactions under a multi-response partially linear varying coefficient model.  

PubMed

Consider the integrative analysis of genetic data with multiple correlated response variables. The goal is to identify important gene-environment (G × E) interactions along with main gene and environment effects that are associated with the responses. The homogeneity and heterogeneity models can be adopted to describe the genetic basis of multiple responses. To accommodate possible nonlinear effects of some environment effects, a multi-response partially linear varying coefficient model is assumed. Penalization is adopted for marker selection. The proposed penalization method can select genetic variants with G × E interactions, no G × E interactions, and no main effects simultaneously. It adopts different penalties to accommodate the homogeneity and heterogeneity models. The proposed method can be effectively computed using a coordinate descent algorithm. Simulation study and the analysis of Health Professionals Follow-up Study, which has two correlated continuous traits, SNP measurements and multiple environment effects, show superior performance of the proposed method over its competitors. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25146388

Wu, Cen; Cui, Yuehua; Ma, Shuangge

2014-12-10

78

Correlation  

Microsoft Academic Search

A spirit of conservatism and caution in regard to intelligence test correlations animates numerous papers. Several writers urge the use of units of rank orders, in the estimating of mental abilities. (See, Boring, McEwen, Michael and the Scott Laboratory). Several others like Ruml, Myers, Mitchell, Thorndike and Thompson hold various views in favor of or in criticism against numerous concepts

J. B. Miner

1920-01-01

79

Aggressively Passive  

E-print Network

AGRESSIVELY PASSIVE DESIGNING WITH CFD ESL-KT-13-12-48 CATEE 2013: Clean Air Through Energy Efficiency Conference, San Antonio, Texas Dec. 16-18 ESL-KT-13-12-48 CATEE 2013: Clean Air Through Energy Efficiency Conference, San Antonio, Texas Dec. 16...-18 Can passive ventilation work in a hot humid climate ESL-KT-13-12-48 CATEE 2013: Clean Air Through Energy Efficiency Conference, San Antonio, Texas Dec. 16-18 ESL-KT-13-12-48 CATEE 2013: Clean Air Through Energy Efficiency Conference, San Antonio...

Upadhyaya, K.

2013-01-01

80

A novel pathological role of p53 in kidney development revealed by gene-environment interactions.  

PubMed

Gene-environment interactions are implicated in congenital human disorders. Accordingly, there is a pressing need to develop animal models of human disease, which are the product of defined gene-environment interactions. Previously, our laboratory demonstrated that gestational salt stress of bradykinin B(2) receptor (B(2)R)-null mice induces renal dysgenesis and early death of the offspring. In contrast, salt-stressed B(2)R +/+ or +/- littermates have normal development. The present study investigates the mechanisms underlying the susceptibility of B(2)R-null mice to renal dysgenesis. Proteomic and conventional Western blot screens identified E-cadherin among the differentially repressed proteins in B(2)R-/- kidneys, whereas the checkpoint kinase Chk1 and its substrate P-Ser(20) p53 were induced. We tested the hypothesis that p53 mediates repression of E-cadherin gene expression and is causally linked to the renal dysgenesis. Genetic crosses between B(2)R -/- and p53+/- mice revealed that germline reduction of p53 gene dosage rescues B(2)R-/- mice from renal dysgenesis and restores kidney E-cadherin gene expression. Furthermore, gamma-irradiation induces repression of E-cadherin gene expression in p53+/+ but not -/- cells. In transient transfection assays, p53 repressed human E-cadherin promoter-driven reporter activity, whereas a mutant p53, which cannot bind DNA, did not. Functional promoter analysis indicated the presence of a p53-responsive element in exon 1, which partially mediates p53-induced repression. Chromatin immunoprecipitation assays revealed that p53 inhibits histone acetylation of the E-cadherin promoter. Treatment with a histone deacetylase inhibitor reversed both p53-mediated promoter repression and deacetylation. In conclusion, this study demonstrates that gene-environment interactions cooperate to induce congenital defects through p53 activation. PMID:15383401

Fan, Hao; Harrell, Jessica R; Dipp, Susana; Saifudeen, Zubaida; El-Dahr, Samir S

2005-01-01

81

[The role of gene-environment interaction in the development of eating disorders].  

PubMed

The biological research predominant in the last decades have not brought a solution in the discovery of risk factors contributing to the development of eating disorders, and elaborating a more effective therapy. The large amount of molecular genetic studies, however, by showing the various genetic vulnerability, contributed significantly to recognizing a more specific effect of the environmental factors. The authors evaluate the genetic studies of eating disorders and present environmental factors having a role in the development of eating disorders. They report about recently published data of gene-environment interaction and conclude from the data clinically applicable consequences. PMID:19949244

Gáti, Agnes; Abrahám, Ildikó

2009-01-01

82

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. PMID:20682755

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

2011-01-01

83

Genetic risk for schizophrenia, obstetric complications, and adolescent school outcome: evidence for gene-environment interaction.  

PubMed

Low birth weight (LBW) and hypoxia are among the environmental factors most reliably associated with schizophrenia; however, the nature of this relationship is unclear and both gene-environment interaction and gene-environment covariation models have been proposed as explanations. High-risk (HR) designs that explore whether obstetric complications differentially predict outcomes in offspring at low risk (LR) vs HR for schizophrenia, while accounting for differences in rates of maternal risk factors, may shed light on this question. This study used prospectively obtained data to examine relationships between LBW and hypoxia on school outcome at age 15-16 years in a Finnish sample of 1070 offspring at LR for schizophrenia and 373 offspring at HR for schizophrenia, based on parental psychiatric history. Controlling for offspring sex, maternal smoking, social support, parity, age, and number of prenatal care visits, HR offspring performed worse than LR offspring across academic, nonacademic, and physical education domains. LBW predicted poorer academic and physical education performance in HR offspring, but not in LR offspring, and this association was similar for offspring of fathers vs mothers with schizophrenia. Hypoxia predicted poorer physical education score across risk groups. Rates of LBW and hypoxia were similar for LR and HR offspring and for offspring of fathers vs mothers with schizophrenia. Results support the hypothesis that genetic susceptibility to schizophrenia confers augmented vulnerability of the developing brain to the effects of obstetric complications, possibly via epigenetic mechanisms. PMID:22941745

Forsyth, Jennifer K; Ellman, Lauren M; Tanskanen, Antti; Mustonen, Ulla; Huttunen, Matti O; Suvisaari, Jaana; Cannon, Tyrone D

2013-09-01

84

Gene-Environment Interaction Research and Transgenic Mouse Models of Alzheimer's Disease  

PubMed Central

The etiology of the sporadic form of Alzheimer's disease (AD) remains largely unknown. Recent evidence has suggested that gene-environment interactions (GxE) may play a crucial role in its development and progression. Whereas various susceptibility loci have been identified, like the apolipoprotein E4 allele, these cannot fully explain the increasing prevalence of AD observed with aging. In addition to such genetic risk factors, various environmental factors have been proposed to alter the risk of developing AD as well as to affect the rate of cognitive decline in AD patients. Nevertheless, aside from the independent effects of genetic and environmental risk factors, their synergistic participation in increasing the risk of developing AD has been sparsely investigated, even though evidence points towards such a direction. Advances in the genetic manipulation of mice, modeling various aspects of the AD pathology, have provided an excellent tool to dissect the effects of genes, environment, and their interactions. In this paper we present several environmental factors implicated in the etiology of AD that have been tested in transgenic animal models of the disease. The focus lies on the concept of GxE and its importance in a multifactorial disease like AD. Additionally, possible mediating mechanisms and future challenges are discussed. PMID:20953364

Chouliaras, L.; Sierksma, A. S. R.; Kenis, G.; Prickaerts, J.; Lemmens, M. A. M.; Brasnjevic, I.; van Donkelaar, E. L.; Martinez-Martinez, P.; Losen, M.; De Baets, M. H.; Kholod, N.; van Leeuwen, F.; Hof, P. R.; van Os, J.; Steinbusch, H. W. M.; van den Hove, D. L. A.; Rutten, B. P. F.

2010-01-01

85

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. PMID:23514120

2013-01-01

86

An exploratory analysis on gene-environment interactions for Parkinson disease.  

PubMed

Little is known about gene-environment interactions in Parkinson disease (PD). We examined potential interactions of smoking and caffeine intake with 10 genome-wide association studies single nucleotide polymorphisms (SNPs) at or near the SNCA, MAPT, LRRK2, and HLA loci among 584 PD patients and 1571 controls. The main effects of these SNPs and environmental exposures were consistent with previous reports. Family history of PD was associated with PD risk (odds ratio = 2.71, 95% confidence interval, 1.97-3.74), which was little affected by further adjustment for these SNPs and environmental exposures. Overall, we did not find significant interactions of either smoking or caffeine intake with these SNPs. However, with a combined smoking and caffeine intake exposure, we found a significant interaction with rs2896905 at SLC2A13, near LRRK2 (p uncorrected = 0.0008). Each A allele was associated with a 35% higher PD risk among never smokers with low caffeine intake, but with a 32% lower risk among smokers with high caffeine intake. This study provides preliminary evidence of a potential gene-environment interaction for PD, which should be investigated in future studies. PMID:22763023

Gao, Jianjun; Nalls, Michael A; Shi, Min; Joubert, Bonnie R; Hernandez, Dena G; Huang, Xuemei; Hollenbeck, Albert; Singleton, Andrew B; Chen, Honglei

2012-10-01

87

Passivity control of a passive haptic device  

Microsoft Academic Search

In this paper, we propose an energy-based stability control of a passive haptic device equipped with passive actuators such as an electric brake. Unstable behavior is observed even in the passive haptic system due to time delay mainly arising from the slow update rate of the virtual environment. The force approximation, one of the major limitations of the passive haptic

Beom-Seop Kim; Mignon Park; Chang-Soon Hwang; Munsang Kim; Changhyun Cho

2004-01-01

88

Gene-Environment Interactions in Parkinson's Disease: The Importance of Animal Modeling  

PubMed Central

Parkinson's disease (PD), a late-onset neurodegenerative disorder, occurs most commonly in a “sporadic” (idiopathic) form, without a clearly defined genetic basis and only a vaguely delineated pathogenesis. Together, the various monogenic forms of PD (i.e., those arising from mutations in single genes) account for a minority of PD cases but have provided crucial insights into disease mechanisms. Although it is commonly believed that sporadic PD is caused by a lifetime of environmental exposures that are superimposed on an individual's composite genetic susceptibility, this hypothesis has not been tested adequately. This article reviews genetic and environmental factors that have been associated with PD and attempts to put these into a pathogenic framework. We argue that animal modeling will become increasingly important in attempting to elucidate gene–environment interactions, to define pathogenic mechanisms, and to provide a platform for testing of targeted therapeutic interventions. PMID:20811350

Horowitz, MP; Greenamyre, JT

2011-01-01

89

CD14 polymorphisms, microbial exposure and allergic diseases: a systematic review of gene-environment interactions.  

PubMed

Asthma and allergy may develop as a result of interactions between environmental factors and the genetic characteristics of an individual. This review aims to summarize the available evidence for, and potential effects of, an interaction between polymorphisms of the CD14 gene and exposure to microbes on the risk of asthma and allergic diseases. We searched PubMed, MEDLINE and Global Health databases, finding 12 articles which met inclusion criteria. Most studies reported a significant interaction between CD14 polymorphisms and microbial exposure. When stratified by age at microbial exposure (early life vs adult life), there was evidence of a protective effect of gene-environment interaction against atopy in children, but not adults. We also found different effects of interaction depending on the type of microbial exposures. There was no strong evidence for asthma and eczema. Future studies should consider a three-way interaction between CD14 gene polymorphisms, microbial exposures and the age of exposure. PMID:24889096

Lau, M Y Z; Dharmage, S C; Burgess, J A; Lowe, A J; Lodge, C J; Campbell, B; Matheson, M C

2014-11-01

90

Timing is critical: gene, environment and timing interactions in genetics of suicide in children and adolescents.  

PubMed

Suicidal behavior runs in families and is prevalent in adolescence. Case-control and family-based studies in this age group failed to find a genetic association that survived replications. Gene environment approach gave new hope for possible associations especially with the short allele of the serotonin transporter promoter polymorphism (5-HTTLPR). However, a recent meta-analysis raised doubts about the consistency of these findings. Some new structural and functional imaging data may shade light on the age-related and gender-related development of the brain. This review suggests a new approach to gene by environment and timing interaction to understand the interplay that leads to suicidality in adolescents and young adults. PMID:20444577

Zalsman, G

2010-06-01

91

Mechanisms of Gene-Environment Interaction Effects in the Development of Conduct Disorder  

PubMed Central

The gene–environment interaction effect in the development of conduct disorder is one of the most important discoveries of the past decade, but the mechanisms through which this effect operates remain elusive. I propose a model of these processes that focuses on the individual’s response to a threatening stimulus in ongoing social interaction. The individual’s response coordinates three interrelated systems: neural, autonomic, and information-processing. In each system, adaptive, evolutionarily selected response patterns characterize normal responding, but in psychopathology these patterns have gone awry. Antecedents of individual differences in these response patterns arise from genetic polymorphisms, adverse environmental experiences early in life, and their interaction. Programs of research are proposed to test hypotheses in the model through longitudinal, experimental, and clinical intervention methods. This model can serve as a template for inquiry in other forms of developmental psychopathology. PMID:19779577

Dodge, Kenneth A.

2009-01-01

92

Defining the Environment in Gene-Environment Research: Lessons From Social Epidemiology  

PubMed Central

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

Daw, Jonathan; Freese, Jeremy

2013-01-01

93

Heart failure in the post-genomics era: gene-environment interactions.  

PubMed

Cardiovascular diseases remain the major cause of mortality and morbidity in the Western world. Heart failure is the most rapidly rising cardiovascular condition and is associated with high mortality. The etiology of heart failure is multiple, ranging from genetic cardiomyopathies to structural modifications to the heart following myocardial infarction or long-standing high blood pressure. Molecular system biology techniques (microarrays and proteomics) in combination with bioinformatics can now provide unique insights into the molecular mechanisms leading to heart failure. Both gene-gene and gene-environment interactions determine the specific phenotype and outcomes in this condition. The identification of these pathways also provides opportunities for the discovery of novel diagnostic and/or prognostic markers, and important therapeutic targets. How recent applications of genomics technologies depict a more complete portrait of molecular events in heart failure is summarized. PMID:16370381

Arab, Sara; Liu, Peter P

2005-12-01

94

Invited commentary: GE-Whiz! Ratcheting gene-environment studies up to the whole genome and the whole exposome.  

PubMed

One goal in the post-genome-wide association study era is characterizing gene-environment interactions, including scanning for interactions with all available polymorphisms, not just those showing significant main effects. In recent years, several approaches to such "gene-environment-wide interaction studies" have been proposed. Two contributions in this issue of the American Journal of Epidemiology provide systematic comparisons of the performance of these various approaches, one based on simulation and one based on application to 2 real genome-wide association study scans for type 2 diabetes. The authors discuss some of the broader issues raised by these contributions, including the plausibility of the gene-environment independence assumption that some of these approaches rely upon, the need for replication, and various generalizations of these approaches. PMID:22199029

Thomas, Duncan C; Lewinger, Juan Pablo; Murcray, Cassandra E; Gauderman, W James

2012-02-01

95

A model of gene-gene and gene-environment interactions and its implications for targeting environmental interventions by genotype  

Microsoft Academic Search

BACKGROUND: The potential public health benefits of targeting environmental interventions by genotype depend on the environmental and genetic contributions to the variance of common diseases, and the magnitude of any gene-environment interaction. In the absence of prior knowledge of all risk factors, twin, family and environmental data may help to define the potential limits of these benefits in a given

Helen M Wallace

2006-01-01

96

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

97

CardioGxE, a catalog of gene-environment interactions for cardiometabolic traits  

PubMed Central

Background Genetic understanding of complex traits has developed immensely over the past decade but remains hampered by incomplete descriptions of contribution to phenotypic variance. Gene-environment (GxE) interactions are one of these contributors and in the guise of diet and physical activity are important modulators of cardiometabolic phenotypes and ensuing diseases. Results We mined the scientific literature to collect GxE interactions from 386 publications for blood lipids, glycemic traits, obesity anthropometrics, vascular measures, inflammation and metabolic syndrome, and introduce CardioGxE, a gene-environment interaction resource. We then analyzed the genes and SNPs supporting cardiometabolic GxEs in order to demonstrate utility of GxE SNPs and to discern characteristics of these important genetic variants. We were able to draw many observations from our extensive analysis of GxEs. 1) The CardioGxE SNPs showed little overlap with variants identified by main effect GWAS, indicating the importance of environmental interactions with genetic factors on cardiometabolic traits. 2) These GxE SNPs were enriched in adaptation to climatic and geographical features, with implications on energy homeostasis and response to physical activity. 3) Comparison to gene networks responding to plasma cholesterol-lowering or regression of atherosclerotic plaques showed that GxE genes have a greater role in those responses, particularly through high-energy diets and fat intake, than do GWAS-identified genes for the same traits. Other aspects of the CardioGxE dataset were explored. Conclusions Overall, we demonstrate that SNPs supporting cardiometabolic GxE interactions often exhibit transcriptional effects or are under positive selection. Still, not all such SNPs can be assigned potential functional or regulatory roles often because data are lacking in specific cell types or from treatments that approximate the environmental factor of the GxE. With research on metabolic related complex disease risk embarking on genome-wide GxE interaction tests, CardioGxE will be a useful resource. PMID:25368670

2014-01-01

98

A novel method for identifying nonlinear gene-environment interactions in case-control association studies.  

PubMed

The genetic influences on complex disease traits generally depend on the joint effects of multiple genetic variants, environmental factors, as well as their interplays. Gene × environment (G × E) interactions play vital roles in determining an individual's disease risk, but the underlying genetic machinery is poorly understood. Traditional analysis assuming linear relationship between genetic and environmental factors, along with their interactions, is commonly pursued under the regression-based framework to examine G × E interactions. This assumption, however, could be violated due to nonlinear responses of genetic variants to environmental stimuli. As an extension to our previous work on continuous traits, we proposed a flexible varying-coefficient model for the detection of nonlinear G × E interaction with binary disease traits. Varying coefficients were approximated by a non-parametric regression function through which one can assess the nonlinear response of genetic factors to environmental changes. A group of statistical tests were proposed to elucidate various mechanisms of G × E interaction. The utility of the proposed method was illustrated via simulation and real data analysis with application to type 2 diabetes. PMID:23974428

Wu, Cen; Cui, Yuehua

2013-12-01

99

Methods for Investigating Gene-Environment Interactions in Candidate Pathway and Genome-Wide Association Studies  

PubMed Central

Despite the considerable enthusiasm about the yield of novel and replicated discoveries of genetic associations from the new generation of genome-wide association studies (GWAS), the proportion of the heritability of most complex diseases that have been studied to date remains small. Some of this “dark matter” could be due to gene-environment (G×E) interactions or more complex pathways involving multiple genes and exposures. We review the basic epidemiologic study design and statistical analysis approaches to studying G×E interactions individually and then consider more comprehensive approaches to studying entire pathways or GWAS data. In addition to the usual issues in genetic association studies, particular care is needed in exposure assessment and very large sample sizes are required. Although hypothesis-driven pathway-based and “agnostic” GWAS approaches are generally viewed as opposite poles, we suggest that the two can be usefully married using hierarchical modeling strategies that exploit external pathway knowledge in mining genome-wide data. PMID:20070199

Thomas, Duncan

2010-01-01

100

Gene-environment interactions: key to unraveling the mystery of Parkinson's disease  

PubMed Central

Parkinson’s disease (PD) is the second most common neurodegenerative disease. The gradual, irreversible loss of dopamine neurons in the substantia nigra isthe signature lesion of PD. Clinical symptoms of PD become apparent when 50–60% of nigral dopamine neurons are lost. PD progresses insidiously for 5–7 years (preclinical period) and then continues to worsen even under the symptomatic treatment. To determine what triggers the disease onset and what drives the chronic, self-propelling neurodegenerative process becomes critical and urgent, since lack of such knowledge impedes the discovery of effective treatments to retard PD progression. At present, available therapeutics only temporarily relieve PD symptoms. While the identification of causative gene defects in familial PD uncovers important genetic influences in this disease, the majority of PD cases are sporadic and idiopathic. The current consensus suggests that PD develops from multiple risk factors including aging, genetic predisposition, and environmental exposure. Here, we briefly review research on the genetic and environmental causes of PD. We also summarize very recent genome-wide association studies on risk gene polymorphisms in the emergence of PD. We highlight the new converging evidence on gene-environment interplay in the development of PD with an emphasis on newly developed multiple-hit PD models involving both genetic lesions and environmental triggers. PMID:21439347

Gao, Hui-Ming; Hong, Jau-shyong

2011-01-01

101

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. PMID:22454369

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

2012-01-01

102

Gene environment interaction studies in depression and suicidal behavior: An update.  

PubMed

Increasing evidence supports the involvement of both heritable and environmental risk factors in major depression (MD) and suicidal behavior (SB). Studies investigating gene-environment interaction (G × E) may be useful for elucidating the role of biological mechanisms in the risk for mental disorders. In the present paper, we review the literature regarding the interaction between genes modulating brain functions and stressful life events in the etiology of MD and SB and discuss their potential added benefit compared to genetic studies only. Within the context of G × E investigation, thus far, only a few reliable results have been obtained, although some genes have consistently shown interactive effects with environmental risk in MD and, to a lesser extent, in SB. Further investigation is required to disentangle the direct and mediated effects that are common or specific to MD and SB. Since traditional G × E studies overall suffer from important methodological limitations, further effort is required to develop novel methodological strategies with an interdisciplinary approach. PMID:23886513

Mandelli, Laura; Serretti, Alessandro

2013-12-01

103

Molecular genetic gene-environment studies using candidate genes in schizophrenia: a systematic review.  

PubMed

The relatively high heritability of schizophrenia suggests that genetic factors play an important role in the etiology of the disorder. On the other hand, a number of environmental factors significantly influence its incidence. As few direct genetic effects have been demonstrated, and there is considerable inter-individual heterogeneity in the response to the known environmental factors, interactions between genetic and environmental factors may be important in determining whether an individual develops the disorder. To date, a considerable number of studies of gene-environment interactions (G×E) in schizophrenia have employed a hypothesis-based molecular genetic approach using candidate genes, which have led to a range of different findings. This systematic review aims to summarize the results from molecular genetic candidate studies and to review challenges and opportunities of this approach in psychosis research. Finally, we discuss the potential of future prospects, such as new studies that combine hypothesis-based molecular genetic candidate approaches with agnostic genome-wide association studies in determining schizophrenia risk. PMID:24094883

Modinos, Gemma; Iyegbe, Conrad; Prata, Diana; Rivera, Margarita; Kempton, Matthew J; Valmaggia, Lucia R; Sham, Pak C; van Os, Jim; McGuire, Philip

2013-11-01

104

Bayesian Mixture Modeling of Gene-Environment and Gene-Gene Interactions  

PubMed Central

With the advent of rapid and relatively cheap genotyping technologies there is now the opportunity to attempt to identify gene-environment and gene-gene interactions when the number of genes and environmental factors is potentially large. Unfortunately the dimensionality of the parameter space leads to a computational explosion in the number of possible interactions that may be investigated. The full model that includes all interactions and main effects can be unstable, with wide confidence intervals arising from the large number of estimated parameters. We describe a hierarchical mixture model that allows all interactions to be investigated simultaneously, but assumes the effects come from a mixture prior with two components, one that reflects small null effects and the second for epidemiologically significant effects. Effects from the former are effectively set to zero, hence increasing the power for the detection of real signals. The prior framework is very flexible, which allows substantive information to be incorporated into the analysis. We illustrate the methods first using simulation, and then on data from a case-control study of lung cancer in Central and Eastern Europe. PMID:19492346

Wakefield, Jon; De Vocht, Frank; Hung, Rayjean J.

2009-01-01

105

Biometric and developmental gene-environment interactions: looking back, moving forward.  

PubMed

A history of research on gene-environment interaction (G x E) is provided in this article, revealing the fact that there have actually been two distinct concepts of G x E since the very origins of this research. R. A. Fisher introduced what I call the biometric concept of G x E (G x EB), whereas Lancelot Hogben introduced what I call the developmental concept of G x E (G x ED). Much of the subsequent history of research on G x E has largely consisted of the separate legacies of these separate concepts, along with the (sometimes acrimonious) disputes that have arisen time and again when employers of each have argued over the appropriate way to conceptualize the phenomenon. With this history in place, more recent attempts to distinguish between different concepts of G x E are considered, paying particular attention to the commonly made distinction between "statistical interaction" and "interactionism," and Michael Rutter's distinction between statistical interaction and "the biological concept of interaction." I argue that the history of the separate legacies of G x EB and G x ED better supports Rutter's analysis of the situation and that this analysis best paves the way for an integrative relationship between the various scientists investigating the place of G x E in the etiology of complex traits. PMID:17931428

Tabery, James

2007-01-01

106

Identification of gene-environment interactions in cancer studies using penalization  

PubMed Central

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

2013-01-01

107

Identification of New Genetic Susceptibility Loci for Breast Cancer Through Consideration of Gene-Environment Interactions  

PubMed Central

Genes that alter disease risk only in combination with certain environmental exposures may not be detected in genetic association analysis. By using methods accounting for gene-environment (G × E) interaction, we aimed to identify novel genetic loci associated with breast cancer risk. Up to 34,475 cases and 34,786 controls of European ancestry from up to 23 studies in the Breast Cancer Association Consortium were included. Overall, 71,527 single nucleotide polymorphisms (SNPs), enriched for association with breast cancer, were tested for interaction with 10 environmental risk factors using three recently proposed hybrid methods and a joint test of association and interaction. Analyses were adjusted for age, study, population stratification, and confounding factors as applicable. Three SNPs in two independent loci showed statistically significant association: SNPs rs10483028 and rs2242714 in perfect linkage disequilibrium on chromosome 21 and rs12197388 in ARID1B on chromosome 6. While rs12197388 was identified using the joint test with parity and with age at menarche (P-values = 3 × 10?07), the variants on chromosome 21 q22.12, which showed interaction with adult body mass index (BMI) in 8,891 postmenopausal women, were identified by all methods applied. SNP rs10483028 was associated with breast cancer in women with a BMI below 25 kg/m2 (OR = 1.26, 95% CI 1.15–1.38) but not in women with a BMI of 30 kg/m2 or higher (OR = 0.89, 95% CI 0.72–1.11, P for interaction = 3.2 × 10?05). Our findings confirm comparable power of the recent methods for detecting G × E interaction and the utility of using G × E interaction analyses to identify new susceptibility loci. PMID:24248812

Schoeps, Anja; Rudolph, Anja; Seibold, Petra; Dunning, Alison M.; Milne, Roger L.; Bojesen, Stig E.; Swerdlow, Anthony; Andrulis, Irene; Brenner, Hermann; Behrens, Sabine; Orr, Nicholas; Jones, Michael; Ashworth, Alan; Li, Jingmei; Cramp, Helen; Connley, Dan; Czene, Kamila; Darabi, Hatef; Chanock, Stephen J.; Lissowska, Jolanta; Figueroa, Jonine D.; Knight, Julia; Glendon, Gord; Mulligan, Anna M.; Dumont, Martine; Severi, Gianluca; Baglietto, Laura; Olson, Janet; Vachon, Celine; Purrington, Kristen; Moisse, Matthieu; Neven, Patrick; Wildiers, Hans; Spurdle, Amanda; Kosma, Veli-Matti; Kataja, Vesa; Hartikainen, Jaana M.; Hamann, Ute; Ko, Yon-Dschun; Dieffenbach, Aida K.; Arndt, Volker; Stegmaier, Christa; Malats, Nuria; Arias Perez, JoseI.; Benitez, Javier; Flyger, Henrik; Nordestgaard, B?rge G.; Truong, Therese; Cordina-Duverger, Emilie; Menegaux, Florence; Silva, Isabel dos Santos; Fletcher, Olivia; Johnson, Nichola; Haberle, Lothar; Beckmann, Matthias W.; Ekici, Arif B.; Braaf, Linde; Atsma, Femke; van den Broek, Alexandra J.; Makalic, Enes; Schmidt, Daniel F.; Southey, Melissa C.; Cox, Angela; Simard, Jacques; Giles, Graham G.; Lambrechts, Diether; Mannermaa, Arto; Brauch, Hiltrud; Guenel, Pascal; Peto, Julian; Fasching, Peter A.; Hopper, John; Flesch-Janys, Dieter; Couch, Fergus; Chenevix-Trench, Georgia; Pharoah, Paul D. P.; Garcia-Closas, Montserrat; Schmidt, Marjanka K.; Hall, Per; Easton, Douglas F.; Chang-Claude, Jenny

2014-01-01

108

Gene-environment interactions between CRHR1 variants and physical assault in suicide attempts.  

PubMed

Risk factors for suicidal behaviors are partly heritable, including genetic variants that drive diathesis-stress in addition to, or by interaction with, exposure to certain stressful life events (SLEs). Hypothalamic-pituitary-adrenal (HPA) axis regulatory genes are candidates for association with suicide as well as its endophenotypes. Using a family-based design of offspring who attempted suicide (SA) and both parents, we investigated gene-environment interactions (G×Es) of SLE exposures with single nucleotide polymorphisms (SNPs) in corticotropin-releasing hormone receptor-1 (CRHR1), a major HPA axis regulatory gene. We observed a novel G×E among predominantly female SA between 5'-SNP rs7209436 and childhood/adolescence physical assault or attack (PA), as well as a second novel and male-specific G×E between 3'-SNP rs16940665 and adulthood PA exposure. A third male-specific G×E previously reported by us among depressed SA, between SNP rs4792887 and cumulative SLEs, was also further confirmed. The two novel G×Es presented here shared the SA characteristic of aggression, while showing differences on other aspects of SA heterogeneity. We conclude that different SA subjects were observed to differentially associate with two novel G×Es involving exposures to PA with different life timing and SNPs located in opposite ends of CRHR1. Concerning sex differences, we observed three subsets of distinct male SA that associated with each of the three observed G×Es, whereas female SAs were affected by only one of the G×Es. These results are consistent with a diathesis-stress model of suicidal behavior and may help to explain SA heterogeneity. PMID:21605337

Ben-Efraim, Y J; Wasserman, D; Wasserman, J; Sokolowski, M

2011-08-01

109

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. 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; 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

110

Passive solar design handbook. Volume 3: Passive solar design analysis  

NASA Astrophysics Data System (ADS)

Simple analytical methods concerning the design of passive solar heating systems are presented with an emphasis on the average annual heating energy consumption. Key terminology and methods are reviewed. The solar load ratio (SLR) is defined, and its relationship to analysis methods is reviewed. The annual calculation, or Load Collector Ratio (LCR) method, is outlined. Sensitivity data are discussed. Information is presented on balancing conservation and passive solar strategies in building design. Detailed analysis data are presented for direct gain and sunspace systems, and details of the systems are described. Key design parameters are discussed in terms of their impact on annual heating performance of the building. These are the sensitivity data. The SLR correlations for the respective system types are described. The monthly calculation, or SLR method, based on the SLR correlations, is reviewed. Performance data are given for 9 direct gain systems and 15 water wall and 42 Trombe wall systems.

Jones, R. W.; Bascomb, J. D.; Kosiewicz, C. E.; Lazarus, G. S.; McFarland, R. D.; Wray, W. O.

1982-07-01

111

The Challenge of Causal Inference in Gene-Environment Interaction Research: Leveraging Research Designs From the Social Sciences  

PubMed Central

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

Conley, Dalton

2013-01-01

112

Passive sonar calibration spheres  

NASA Astrophysics Data System (ADS)

The need for calibrated sonar targets is addressed with the development and testing of a set of thin-walled spheres filled with a high-density fluid. Using historical research information as a guide, a set of thin-walled metal spheres was developed and filled with a high-density fluid. The combination of the spherical shape and the acoustic focusing effects of the fluid enhanced the acoustic scattering strength of the shape so that it was not only stable with temperature but also significantly greater in amplitude. The simple passive nature of the spheres makes them ideal acoustic targets for long-term unattended deployments. Using a reference level measurement, each sphere was calibrated over a wide frequency range in order to provide the user with a curve of measured scattering strength versus frequency. The resulting curves showed a high degree of correlation between the individual spheres and the modeling that was used to extrapolate the theoretical values.

Deveau, David M.

2002-05-01

113

Early-life stress and antidepressants modulate peripheral biomarkers in a gene–environment rat model of depression  

Microsoft Academic Search

BackgroundAvailability of peripheral biomarkers for depression could aid diagnosis and help to predict treatment response. The objective of this work was to analyse the peripheral biomarker response in a gene–environment interaction model of depression. Genetically selected Flinders Sensitive Line (FSL) rats were subjected to maternal separation (MS), since early-life trauma is an important antecedent of depression. An open-ended approach based

Lucia Carboni; Serena Becchi; Chiara Piubelli; Alessandra Mallei; Roberto Giambelli; Maria Razzoli; Aleksander A. Mathé; Maurizio Popoli; Enrico Domenici

2010-01-01

114

Fundamental studies on passivity and passivity breakdown  

SciTech Connect

Using photoelectrochemical impedance and admittance spectroscopies, a fundamental and quantitative understanding of the mechanisms for the growth and breakdown of passive films on metal and alloy surfaces in contact with aqueous environments is being developed. A point defect model has been extended to explain the breakdown of passive films, leading to pitting and crack growth and thus development of damage due to localized corrosion.

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

1993-06-01

115

From Reflexive to Passive  

E-print Network

Previous approaches to the passive development from a reflexive marking focus on how the former is similar to the latter semantically and syntactically. I show that the passive evolution is better understood by looking at ...

Sohn, Joong-Sun

1998-01-01

116

Passive storage technologies  

NASA Astrophysics Data System (ADS)

Advances in storage technology and how passive techniques could be applied to the storage of propellants at the space station are described. The devices considered are passive orbital disconnect struts, cooled shield optimization, liftweight shields and catalytic converters.

Kittel, P.

1984-04-01

117

Tropospheric Passive Remote Sensing  

NASA Technical Reports Server (NTRS)

The long term role of airborne/spaceborne passive remote sensing systems for tropospheric air quality research and the identification of technology advances required to improve the performance of passive remote sensing systems were discussed.

Keafer, L. S., Jr. (editor)

1982-01-01

118

Passivation of Anodic Reactions.  

National Technical Information Service (NTIS)

Extending the Wagner definition of passivity to anodic reactions of chemical species on inert electrodes, passivation of a Pt electrode for the hydrogen oxidation reaction can be explained as being caused by small amounts (fraction of a monolayer) of adso...

S. Schuldiner

1968-01-01

119

Interlanguage Passive Construction  

ERIC Educational Resources Information Center

Because the appearance of the passive construction varies cross linguistically, differences exist in the interlanguage (IL) passives attempted by learners of English. One such difference is the widely studied IL pseudo passive, as in "*new cars must keep inside" produced by Chinese speakers. The belief that this is a reflection of L1 language…

Simargool, Nirada

2008-01-01

120

Gene-environment interplay in Drosophila melanogaster: Chronic nutritional deprivation in larval life affects adult fecal output.  

PubMed

Life history consequences of stress in early life are varied and known to have lasting impacts on the fitness of an organism. Gene-environment interactions play a large role in how phenotypic differences are mediated by stressful conditions during development. Here we use natural allelic 'rover/sitter' variants of the foraging (for) gene and chronic early life nutrient deprivation to investigate gene-environment interactions on excretion phenotypes. Excretion assay analysis and a fully factorial nutritional regimen encompassing the larval and adult life cycle of Drosophila melanogaster were used to assess the effects of larval and adult nutritional stress on adult excretion phenotypes. Natural allelic variants of for exhibited differences in the number of fecal spots when they were nutritionally deprived as larvae and well fed as adults. for mediates the excretion response to chronic early-life nutritional stress in mated female, virgin female, and male rovers and sitters. Transgenic manipulations of for in a sitter genetic background under larval but not adult food deprivation increases the number of fecal spots. Our study shows that food deprivation early in life affects adult excretion phenotypes and these excretion differences are mediated by for. PMID:24929224

Urquhart-Cronish, Mackenzie; Sokolowski, Marla B

2014-10-01

121

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

122

Passive magnetic bearing configurations  

DOEpatents

A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

Post, Richard F. (Walnut Creek, CA)

2011-01-25

123

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

124

Passive Optical PassiveOpticalNetworks Contents  

E-print Network

Optical Networks (PON) · TDM-PON ­ Physical Layer and Devices ­ Traffic Distribution/Scheduling ­ Power Budget ­ Standards · APON/BPON · EPON · GPON · WDM-PONs ­ Proposed solutions #12;Passive. There is the need for specific access network technologies Access Network Hub Remote node Remote node ... NIU NIU

Mellia, Marco

125

A Twin and Adoption Study of Reading Achievement: Exploration of Shared-Environmental and Gene-Environment-Interaction Effects  

PubMed Central

Existing behavior-genetic research implicates substantial influence of heredity and modest influence of shared environment on reading achievement and reading disability. Applying DeFries-Fulker analysis to a combined sample of twins and adoptees (N = 4,886, including 266 reading-disabled probands), the present study replicates prior findings of considerable heritability for both reading achievement and reading disability. A simple biometric model adequately described parent and offspring data (combined N = 9,430 parents and offspring) across differing types of families present in the sample Analyses yielded a high heritability estimate (around 0.70) and a negligible shared-environmentality estimate for both reading achievement and reading disability. No evidence of gene × environment interaction was found for parental reading ability and parental educational attainment, the two moderators analyzed. PMID:21743785

Kirkpatrick, Robert M.; Legrand, Lisa N.; Iacono, William G.; McGue, Matt

2011-01-01

126

A Twin and Adoption Study of Reading Achievement: Exploration of Shared-Environmental and Gene-Environment-Interaction Effects.  

PubMed

Existing behavior-genetic research implicates substantial influence of heredity and modest influence of shared environment on reading achievement and reading disability. Applying DeFries-Fulker analysis to a combined sample of twins and adoptees (N = 4,886, including 266 reading-disabled probands), the present study replicates prior findings of considerable heritability for both reading achievement and reading disability. A simple biometric model adequately described parent and offspring data (combined N = 9,430 parents and offspring) across differing types of families present in the sample Analyses yielded a high heritability estimate (around 0.70) and a negligible shared-environmentality estimate for both reading achievement and reading disability. No evidence of gene × environment interaction was found for parental reading ability and parental educational attainment, the two moderators analyzed. PMID:21743785

Kirkpatrick, Robert M; Legrand, Lisa N; Iacono, William G; McGue, Matt

2011-08-01

127

Characterization of 9p24 risk locus and colorectal adenoma and cancer: gene-environment interaction and meta-analysis  

PubMed Central

Background A potential susceptibility locus for colorectal cancer on chromosome 9p24 (rs719725) was initially identified through a genome-wide association study, though replication attempts have been inconclusive. Methods We genotyped this locus and explored interactions with known risk factors as potential sources of heterogeneity, which may explain the previously inconsistent replication. We included Caucasians with colorectal adenoma or colorectal cancer and controls from four studies (total 3891 cases, 4490 controls): the Women’s Health Initiative (WHI); the Diet, Activity and Lifestyle Study (DALS); a Minnesota population-based case-control study (MinnCCS); and the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO). We used logistic regression to evaluate the association and test for gene-environment interactions. Results SNP rs719725 was statistically significantly associated with risk of colorectal cancer in WHI (OR per A allele 1.19; 95% CI 1.01–1.40; p-trend 0.04), marginally associated with adenoma risk in PLCO (OR per A allele 1.11; 95% CI 0.99–1.25; p-trend 0.07), and not associated in DALS and MinnCCS. Evaluating for gene-environment interactions yielded no consistent results across the studies. A meta-analysis of seventeen studies (including these four) gave an OR per A allele of 1.07 (95% CI 1.03–1.12; p-trend 0.001). Conclusions Our results suggest the A allele for SNP rs719725 at locus 9p24 is positively associated with a small increase in risk for colorectal tumors. Environmental risk factors for colorectal cancer do not appear to explain heterogeneity across studies. Impact If this finding is supported by further replication and functional studies, it may highlight new pathways underlying colorectal neoplasia. PMID:20978172

Kocarnik, Jonathan D.; Hutter, Carolyn M.; Slattery, Martha L.; Berndt, Sonja I.; Hsu, Li; Duggan, David J.; Muehling, Jill; Caan, Bette J.; Beresford, Shirley A.A.; Rajkovic, Aleksandar; Sarto, Gloria E.; Marshall, James R.; Hammad, Nazik; Wallace, Robert B.; Makar, Karen W.; Prentice, Ross L.; Potter, John D.; Hayes, Richard B.; Peters, Ulrike

2010-01-01

128

The role of covariate heterogeneity in meta-analysis of gene-environment interactions with quantitative traits  

PubMed Central

With challenges in data harmonization and covariate heterogeneity across various data sources, meta-analysis of gene-environment interaction studies can often involve subtle statistical issues. In this paper, we study the effect of environmental covariate heterogeneity (within and between cohorts) on two approaches for fixed-effect meta-analysis: the standard inverse-variance weighted meta-analysis and a meta-regression approach. Akin to the results in Simmonds and Higgins (2007), we obtain analytic efficiency results for both methods under the assumption of gene-environment independence. The relative efficiency of the two methods depends on the ratio of within- versus between- cohort variability of the environmental covariate. We propose to use an adaptively weighted estimator (AWE), between meta-analysis and meta-regression, for the interaction parameter. The AWE retains full efficiency of the joint analysis using individual level data under certain natural assumptions. Lin and Zeng (2010a, b) showed that a multivariate inverse-variance weighted estimator also had asymptotically full efficiency as joint analysis using individual level data, if the estimates with full covariance matrices for all the common parameters are pooled across all studies. We show consistency of our work with Lin and Zeng (2010a, b). Without sacrificing much efficiency, the AWE uses only univariate summary statistics from each study, and bypasses issues with sharing individual level data or full covariance matrices across studies. We compare the performance of the methods both analytically and numerically. The methods are illustrated through meta-analysis of interaction between Single Nucleotide Polymorphisms in FTO gene and body mass index on high-density lipoprotein cholesterol data from a set of eight studies of type 2 diabetes. PMID:24801060

Li, Shi; Mukherjee, Bhramar; Taylor, Jeremy M.G.; Rice, Kenneth M.; XiaoquanWen; Rice, John D.; Stringham, Heather M.; Boehnke, Michael

2014-01-01

129

Hood River Passive House  

SciTech Connect

The Hood River Passive Project was developed by Root Design Build of Hood River Oregon using the Passive House Planning Package (PHPP) to meet all of the requirements for certification under the European Passive House standards. The Passive House design approach has been gaining momentum among residential designers for custom homes and BEopt modeling indicates that these designs may actually exceed the goal of the U.S. Department of Energy's (DOE) Building America program to reduce home energy use by 30%-50% (compared to 2009 energy codes for new homes). This report documents the short term test results of the Shift House and compares the results of PHPP and BEopt modeling of the project.

Hales, D.

2013-03-01

130

Acquisition of the Passive  

E-print Network

This single-subject pilot study, modeled after de Villiers' 1973, investigates the subject's acquisition of the passive construction (i.e., 'The boy was hit by the girl', as opposed to The girl hit the boy'). The purposes ...

Hill, Francine

1998-01-01

131

Immunizations: Active vs. Passive  

MedlinePLUS

... physicians call passive immunizations. If you hear your pediatrician use these terms, this is what they mean. When your child receives an active immunization, the vaccine prevents an infectious disease by activating the body’s ...

132

Passive solar water heaters  

SciTech Connect

Complete descriptions and analyses of batch integral passive, solar water heaters from the first ones in this country in the 1800s to today's latest designs are provided. Separate abstracts were prepared for nine chapters in this book.

Howell, J. (ed.)

1983-01-01

133

Passive microfluidic interconnects  

E-print Network

Equipment and procedures were developed to test two passive microfluidic interconnect rings held together by the friction forces on the contact surfaces. The second design forms fluid seals by means of thin flared rings ...

Jonnalagadda, Aparna S

2005-01-01

134

The clinical application of UGT1A1 pharmacogenetic testing: Gene-environment interactions  

PubMed Central

Over the past decade, the number of pharmacogenetic tests has increased considerably, allowing for the development of our knowledge of their clinical application. The uridine diphosphate glucuronosyltransferase 1A1 gene (UGT1A1) assay is an example of a pharmacogenetic test. Numerous variants have been found in UGT1A1, the main conjugating enzyme of bilirubin and drugs such as the anticancer drug irinotecan. Recently, the US Food and Drug Administration (FDA) recommended testing for the presence of UGT1A1*28, an allele correlated with decreased transcriptional activity, to predict patients at risk of irinotecan toxicity. The administration of other drugs -- such as inhibitors of the UGT1A1 enzyme -- can clinically mimic the *28 phenotype, whereas inducers of UGT1A1 can increase the glucuronidation rate of the enzyme. The *28 polymorphism is not present in all ethnicities at a similar frequency, which suggests that it is important to study different populations to determine the clinical relevance of testing for UGT1A1*28 and to identify other clinically relevant UGT1A1 variants. Environmental factors such as lifestyle can also affect UGT1A1 activity. This review is a critical analysis of studies on drugs that can be affected by the presence of UGT1A1*28, the distribution of this polymorphism around the globe, distinct variants that may be clinically significant in African and Asian populations and how lifestyle can affect treatment outcomes that depend on UGT1A1 activity. PMID:20511137

2010-01-01

135

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

136

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

2013-01-01

137

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. PMID:19209988

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

2010-01-01

138

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

PubMed Central

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.

2012-01-01

139

Pulse pressure relation to aortic and left ventricular structure in the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study.  

PubMed

High pulse pressure, a major cardiovascular risk factor, has been attributed to medial elastic fiber degeneration and aortic dilation, which transfers hemodynamic load to stiffer collagen. However, recent studies suggest higher pulse pressure is instead associated with smaller aortic diameter. Thus, we sought to elucidate relations of pulse pressure with aortic stiffness and aortic and cardiac dimensions. We used magnetic resonance imaging to examine relationships of pulse pressure with lumen area and wall stiffness and thickness in the thoracic aorta and left ventricular structure in 526 participants (72-94 years of age, 295 women) in the community-based Age, Gene/Environment Susceptibility-Reykjavik Study. In a multivariable model that adjusted for age, sex, height, weight, and standard vascular risk factors, central pulse pressure had a negative relationship with aortic lumen area (all effects expressed as mm Hg/SD; B=-8.1±1.2; P<0.001) and positive relationships with left ventricular end-diastolic volume (B=3.8±1.0; P<0.001), carotid-femoral pulse wave velocity (B=3.6±1.0; P<0.001), and aortic wall area (B=3.0±1.2; P=0.015). Higher pulse pressure in older people is associated with smaller aortic lumen area and greater aortic wall stiffness and thickness and left ventricular volume. Relationships of larger ventricular volume and smaller aortic lumen with higher pulse pressure suggest mismatch in hemodynamic load accommodation by the heart and aorta in older people. PMID:25024287

Torjesen, Alyssa A; Sigurðsson, Sigurður; Westenberg, Jos J M; Gotal, John D; Bell, Vanessa; Aspelund, Thor; Launer, Lenore J; de Roos, Albert; Gudnason, Vilmundur; Harris, Tamara B; Mitchell, Gary F

2014-10-01

140

The Influence of Major Life Events on Economic Attitudes in a World of Gene-Environment Interplay  

PubMed Central

The role of “genes” on political attitudes has gained attention across disciplines. However, person-specific experiences have yet to be incorporated into models that consider genetic influences. Relying on a gene-environment interplay approach, this study explicates how life-events, such as losing one’s job or suffering a financial loss, influence economic policy attitudes. The results indicate genetic and environmental variance on support for unions, immigration, capitalism, socialism and property tax is moderated by financial risks. Changes in the magnitude of genetic influences, however, are temporary. After two years, the phenotypic effects of the life events remain on most attitudes, but changes in the sources of individual differences do not. Univariate twin models that estimate the independent contributions of genes and environment on the variation of attitudes appear to provide robust baseline indicators of sources of individual differences. These estimates, however, are not event or day specific. In this way, genetic influences add stability, while environment cues change, and this process is continually updated. PMID:24860199

Hatemi, Peter K.

2014-01-01

141

Through Passive Measurements  

Microsoft Academic Search

We propose a passive measurement method- ology to infer and keep track of the values of two important variables associated with a TCP connection: the sender's congestion window (cwnd) and the connection round trip time (RTT). Together, these variables provide a valuable diagnostic of end-user-perceived network performance. Our methodology is validated via both simulation and concurrent active measurements, and is

Sharad Jaiswal; Gianluca Iannaccone; Christophe Diot; Jim Kurose; Don Towsley

142

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. PMID:23215821

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

143

Novel likelihood ratio tests for screening gene-gene and gene-environment interactions with unbalanced repeated-measures data.  

PubMed

There has been extensive literature on modeling gene-gene interaction (GGI) and gene-environment interaction (GEI) in case-control studies with limited literature on statistical methods for GGI and GEI in longitudinal cohort studies. We borrow ideas from the classical two-way analysis of variance literature to address the issue of robust modeling of interactions in repeated-measures studies. While classical interaction models proposed by Tukey and Mandel have interaction structures as a function of main effects, a newer class of models, additive main effects and multiplicative interaction (AMMI) models, do not have similar restrictive assumptions on the interaction structure. AMMI entails a singular value decomposition of the cell residual matrix after fitting the additive main effects and has been shown to perform well across various interaction structures. We consider these models for testing GGI and GEI from two perspectives: likelihood ratio test based on cell means and a regression-based approach using individual observations. Simulation results indicate that both approaches for AMMI models lead to valid tests in terms of maintaining the type I error rate, with the regression approach having better power properties. The performance of these models was evaluated across different interaction structures and 12 common epistasis patterns. In summary, AMMI model is robust with respect to misspecified interaction structure and is a useful screening tool for interaction even in the absence of main effects. We use the proposed methods to examine the interplay between the hemochromatosis gene and cumulative lead exposure on pulse pressure in the Normative Aging Study. PMID:23798480

Ko, Yi-An; Saha-Chaudhuri, Paramita; Park, Sung Kyun; Vokonas, Pantel Steve; Mukherjee, Bhramar

2013-09-01

144

Gene-environment interplay in alcoholism and other substance abuse disorders: expressions of heritability and factors influencing vulnerability.  

PubMed

Factors that confer predisposition and vulnerability for alcoholism and other substance abuse disorders may be described usefully within the gene-environment interplay framework. Thus, it is postulated that heritability provides a major contribution not only to alcohol but also to other substances of abuse. Studies of evoked potential amplitude reduction have provided a highly suitable and testable method for the assessment of both environmentally-determined and heritable characteristics pertaining to substance use and dependence. The different personal attributes that may co-exist with parental influence or exist in a shared, monozygotic relationship contribute to the final expression of addiction. In this connection, it appears that personality disorders are highly prevalent co-morbid conditions among addicted individuals, and, this co-morbidity is likely to be accounted for by multiple complex etiological relationships, not least in adolescent individuals. Co-morbidity associated with deficient executive functioning may be observed too in alcohol-related aggressiveness and crimes of violence. The successful intervention into alcohol dependence and craving brought about by baclofen in both human and animal studies elucidates glutamatergic mechanisms in alcoholism whereas the role of the dopamine transporter, in conjunction with both the noradrenergic and serotonergic transporters, are implicated in cocaine dependence and craving. The role of the cannabinoids in ontogeny through an influence upon the expression of key genes for the development of neurotransmitter systems must be considered. Finally, the particular form of behaviour/characteristic outcome due to childhood circumstance may lie with biological, gene-based determinants, for example individual characteristics of monoamine oxidase (MAO) activity levels, thereby rendering simple predictive measures both redundant and misguiding. PMID:15545018

Palomo, Tomas; Kostrzewa, R M; Beninger, R J; Archer, T

2004-01-01

145

SEROTONIN PATHWAY GENE-GENE AND GENE-ENVIRONMENT INTERACTIONS INFLUENCE BEHAVIORAL STRESS RESPONSE IN INFANT RHESUS MACAQUES  

PubMed Central

A subset of serotonin pathway polymorphisms has been shown to confer risk for psychological dysfunction, particularly in individuals who experience early adversity. Understanding the developmental processes underlying these gene × environment interactions will strengthen the search for risk factors for behavioral dysfunction. We investigated the combined influence of two serotonin pathway polymorphisms and species-atypical, and possibly adverse, rearing (nursery-rearing, NR) on two dimensions of behavioral stress response in infant rhesus macaques. We hypothesized that the experience of NR and possession of both “high risk” genotypes (genotypes that are thought to confer low 5-HT function) would predict the greatest behavioral stress response to maternal/social separation. Using a matched-pair design, the impact of early experience and the serotonin transporter [rh5-HTTLPR] and monoamine oxidase A [rhMAO-A-LPR] promoter polymorphisms on behavioral reactivity of 136 infant rhesus macaques (90–120 days of age) during a 25-hour social separation/relocation procedure was assessed. Each pair included one infant reared with mother in a large, outdoor field enclosure (FR) and one infant reared in a nursery (NR). Pairs were matched for putative gene activity of each polymorphism, sex, age and weight at testing. Behavioral responses in a “Human Intruder” test were recorded, and Activity and Emotional Reactivity composites were created to detect different aspects of psychological adaptation to stress. Our hypothesis that high-risk groups would be the most reactive to stress was not entirely borne out. Rh5-HTTLPR × rhMAOA-LPR interactions predicted Emotional Reactivity and tended to predict Behavioral Activity scores. However, this interaction was exacerbated by the experience of nursery rearing. We conclude that serotonin pathway multigene-environment interactions influence behavioral development in rhesus macaques. PMID:20102645

Kinnally, Erin L.; Karere, Genesio. M.; Lyons, Leslie A.; Mendoza, Sally P.; Mason, William A.; Capitanio, John P.

2011-01-01

146

The role of environmental heterogeneity in meta-analysis of gene-environment interactions with quantitative traits.  

PubMed

With challenges in data harmonization and environmental heterogeneity across various data sources, meta-analysis of gene-environment interaction studies can often involve subtle statistical issues. In this paper, we study the effect of environmental covariate heterogeneity (within and between cohorts) on two approaches for fixed-effect meta-analysis: the standard inverse-variance weighted meta-analysis and a meta-regression approach. Akin to the results in Simmonds and Higgins (), we obtain analytic efficiency results for both methods under certain assumptions. The relative efficiency of the two methods depends on the ratio of within versus between cohort variability of the environmental covariate. We propose to use an adaptively weighted estimator (AWE), between meta-analysis and meta-regression, for the interaction parameter. The AWE retains full efficiency of the joint analysis using individual level data under certain natural assumptions. Lin and Zeng (2010a, b) showed that a multivariate inverse-variance weighted estimator retains full efficiency as joint analysis using individual level data, if the estimates with full covariance matrices for all the common parameters are pooled across all studies. We show consistency of our work with Lin and Zeng (2010a, b). Without sacrificing much efficiency, the AWE uses only univariate summary statistics from each study, and bypasses issues with sharing individual level data or full covariance matrices across studies. We compare the performance of the methods both analytically and numerically. The methods are illustrated through meta-analysis of interaction between Single Nucleotide Polymorphisms in FTO gene and body mass index on high-density lipoprotein cholesterol data from a set of eight studies of type 2 diabetes. PMID:24801060

Li, Shi; Mukherjee, Bhramar; Taylor, Jeremy M G; Rice, Kenneth M; Wen, Xiaoquan; Rice, John D; Stringham, Heather M; Boehnke, Michael

2014-07-01

147

Effects of prenatal hypoxia on schizophrenia-related phenotypes in heterozygous reeler mice: a gene × environment interaction study.  

PubMed

Both genetic and environmental factors play important roles in the pathophysiology of schizophrenia. Although prenatal hypoxia is a potential environmental factor implicated in schizophrenia, very little is known about the consequences of combining models of genetic risk factor with prenatal hypoxia. Heterozygous reeler (haploinsufficient for reelin; HRM) and wild-type (WT) mice were exposed to prenatal hypoxia (9% oxygen for two hour) or normoxia at embryonic day 17 (E17). Behavioral (Prepulse inhibition, Y-maze and Open field) and functional (regional volume in frontal cortex and hippocampus as well as hippocampal blood flow) tests were performed at 3 months of age. The levels of hypoxia and stress-related molecules such as hypoxia-inducible factor-1 ? (HIF-1?), vascular endothelial factor (VEGF), VEGF receptor-2 (VEGFR2/Flk1) and glucocorticoid receptor (GR) were examined in frontal cortex and hippocampus at E18, 1 month and 3 months of age. In addition, serum VEGF and corticosterone levels were also examined. Prenatal hypoxia induced anxiety-like behavior in both HRM and WT mice. A significant reduction in hippocampal blood flow, but no change in brain regional volume was observed following prenatal hypoxia. Significant age and region-dependent changes in HIF-1?, VEGF, Flk1 and GR were found following prenatal hypoxia. Serum VEGF and corticosterone levels were found decreased following prenatal hypoxia. None of the above prenatal hypoxia-induced changes were either diminished or exacerbated due to reelin deficiency. These results argue against any gene-environment interaction between hypoxia and reelin deficiency. PMID:24946696

Howell, Kristy R; Pillai, Anilkumar

2014-08-01

148

Epigenetic Genes and Emotional Reactivity to Daily Life Events: A Multi-Step Gene-Environment Interaction Study  

PubMed Central

Recent human and animal studies suggest that epigenetic mechanisms mediate the impact of environment on development of mental disorders. Therefore, we hypothesized that polymorphisms in epigenetic-regulatory genes impact stress-induced emotional changes. A multi-step, multi-sample gene-environment interaction analysis was conducted to test whether 31 single nucleotide polymorphisms (SNPs) in epigenetic-regulatory genes, i.e. three DNA methyltransferase genes DNMT1, DNMT3A, DNMT3B, and methylenetetrahydrofolate reductase (MTHFR), moderate emotional responses to stressful and pleasant stimuli in daily life as measured by Experience Sampling Methodology (ESM). In the first step, main and interactive effects were tested in a sample of 112 healthy individuals. Significant associations in this discovery sample were then investigated in a population-based sample of 434 individuals for replication. SNPs showing significant effects in both the discovery and replication samples were subsequently tested in three other samples of: (i) 85 unaffected siblings of patients with psychosis, (ii) 110 patients with psychotic disorders, and iii) 126 patients with a history of major depressive disorder. Multilevel linear regression analyses showed no significant association between SNPs and negative affect or positive affect. No SNPs moderated the effect of pleasant stimuli on positive affect. Three SNPs of DNMT3A (rs11683424, rs1465764, rs1465825) and 1 SNP of MTHFR (rs1801131) moderated the effect of stressful events on negative affect. Only rs11683424 of DNMT3A showed consistent directions of effect in the majority of the 5 samples. These data provide the first evidence that emotional responses to daily life stressors may be moderated by genetic variation in the genes involved in the epigenetic machinery. PMID:24967710

Pishva, Ehsan; Drukker, Marjan; Viechtbauer, Wolfgang; Decoster, Jeroen; Collip, Dina; van Winkel, Ruud; Wichers, Marieke; Jacobs, Nele; Thiery, Evert; Derom, Catherine; Geschwind, Nicole; van den Hove, Daniel; Lataster, Tineke; Myin-Germeys, Inez; van Os, Jim

2014-01-01

149

Regional passive solar design charts  

Microsoft Academic Search

The need for simple, accurate hand calculations of passive solar system performance leads to developent of region-specific passive solar design charts. The passive solar design chart requires, as an input, collector area instead of solar radiation. Annual solar heating fraction is output instead of monthly solar heating fraction. Computational effect for hand calculations is reduced by a factor of 10.

M. Utzinger; R. Bercovitz

1982-01-01

150

Passivated niobium cavities  

DOEpatents

A niobium cavity exhibiting high quality factors at high gradients is provided by treating a niobium cavity through a process comprising: 1) removing surface oxides by plasma etching or a similar process; 2) removing hydrogen or other gases absorbed in the bulk niobium by high temperature treatment of the cavity under ultra high vacuum to achieve hydrogen outgassing; and 3) assuring the long term chemical stability of the niobium cavity by applying a passivating layer of a superconducting material having a superconducting transition temperature higher than niobium thereby reducing losses from electron (cooper pair) scattering in the near surface region of the interior of the niobium cavity. According to a preferred embodiment, the passivating layer comprises niobium nitride (NbN) applied by reactive sputtering.

Myneni, Ganapati Rao (Yorktown, VA); Hjorvarsson, Bjorgvin (Lagga Arby, SE); Ciovati, Gianluigi (Newport News, VA)

2006-12-19

151

Passive solar buildings research  

SciTech Connect

This chapter covers research advances in passive solar buildings research during the time span from 1982 through 1991. These advances fall within the following categories: (1) short-term energy monitoring, (2) heat transport by natural convection within buildings, and (3) design guidelines and design tools. In short-term energy monitoring, a simulation model of the building is calibrated, based on data taken in a 3-day test. The method accurately predicts performance over an extended period. Heat transport through doorways is characterized for complex situations that arise in passive solar buildings. Simple concepts and models adequately describe the energy transport in many situations of interest. In a new approach, design guidelines are automatically generated for any specific locality. Worksheets or an accompanying computer program allow the designer to quickly and accurately evaluate performance and investigate design alternatives. 29 refs., 19 figs., 2 tabs.

Balcomb, J.D.

1992-12-31

152

Asymmetric passive dynamic walker.  

PubMed

The objective of this research is to better understand the dynamics of gait asymmetry in humans with central nervous system damage, such as stroke, by using a model of a passive dynamic walker (PDW). By changing the mass, mass location, knee location, and leg length of one leg while leaving the parameters of the other leg unchanged, we show that stable asymmetric walking patterns exist for PDW models. The asymmetric PDW model shows several stable walking patterns that have a single, double, and quadruple repeat pattern where the step lengths between the two legs differ by over 15%. This model will allow an analysis of the passive dynamics of walking separate from the cognitive control in asymmetric human walking to test different gait rehabilitation hypotheses. PMID:22275663

Honeycutt, Craig; Sushko, John; Reed, Kyle B

2011-01-01

153

Passive fetal monitoring sensor  

NASA Technical Reports Server (NTRS)

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. (inventor); Hall, Earl T. (inventor); Baker, Donald A. (inventor); Bryant, Timothy D. (inventor)

1992-01-01

154

Subject, topic and Sesotho passive.  

PubMed

Counter to findings in English, German and Hebrew, recent acquisition studies have shown that the passive is acquired early in several non-Indo-European languages. In an attempt to explain this phenomenon, this paper addresses certain typological phenomena which influence the early acquisition of passives in Sesotho, a southern Bantu language. After outlining the structure of the Sesotho passive and its syntactic and discourse functions, I examine Sesotho-speaking children's spontaneous use of passives, showing that the acquisition of passives in Sesotho is closely linked to the fact that Sesotho subjects must be discourse topics. I conclude that a detailed examination of how passive constructions interact with other components of a given linguistic system is critical for developing a coherent and universally applicable theory of how passives are acquired. PMID:2312646

Demuth, K

1990-02-01

155

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

156

Passive propellant system  

NASA Technical Reports Server (NTRS)

A passive propellant acquisition and feed system is disclosed which acquires and feeds gas-free propellant in low or zero-g environments during orbital maneuvers and retains this propellant under high axially directed acceleration such as may be experienced during launch of a space vehicle and orbit-to-orbit transfer is described. The propellant system includes a dual compartment propellant tank with independent surface tension acquisition channels in each compartment to provide gas-free flow of pressurized liquid propellant from one compartment to the other in one direction only.

Hess, D. A.; Regnier, W. W.; Jacobs, V. L. (inventors)

1979-01-01

157

Optimizing Passive Quantum Clocks  

E-print Network

We describe protocols for passive atomic clocks based on quantum interrogation of the atoms. Unlike previous techniques, our protocols are adaptive and take advantage of prior information about the clock's state. To reduce deviations from an ideal clock, each interrogation is optimized by means of a semidefinite program for atomic state preparation and measurement whose objective function depends on the prior information. Our knowledge of the clock's state is maintained according to a Bayesian model that accounts for noise and measurement results. We implement a full simulation of a running clock with power-law noise models and find significant improvements by applying our techniques.

Michael Mullan; Emanuel Knill

2014-04-15

158

Passive solar wall collectors  

NASA Astrophysics Data System (ADS)

A study of front covers to be used in passive solar wall systems for building insulation is presented. Nineteen covers were investigated, including glass, translucid plastics and metal plates. The measurements were made under natural conditions on small concrete elements of about 0.5 sq m front surface. A mathematical model was developed and adapted to each case; by fitting the different measured curves, all the physical characteristics of the different covers were obtained. The measurements for 19 covers were presented; the results of a mathematical simulation based on meteorological data near Lausanne of two periods during the 1976-1977 winter were presented for four covers

Faist, A.; Gay, J. B.

159

Optimizing passive quantum clocks  

NASA Astrophysics Data System (ADS)

We describe protocols for passive atomic clocks based on quantum interrogation of the atoms. Unlike previous techniques, our protocols are adaptive and take advantage of prior information about the clock's state. To reduce deviations from an ideal clock, each interrogation is optimized by means of a semidefinite program for atomic state preparation and measurement whose objective function depends on the prior information. Our knowledge of the clock's state is maintained according to a Bayesian model that accounts for noise and measurement results. We implement a full simulation of a running clock with power-law noise models and find significant improvements by applying our techniques.

Mullan, Michael; Knill, Emanuel

2014-10-01

160

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

PubMed

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. PMID:22075523

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

2011-11-01

161

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. PMID:22075523

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

162

Active/Passive Infrared Imaging  

NASA Astrophysics Data System (ADS)

An active/passive CO2 laser radar target acquisition sensor has been developed through cooperation of the United States Army, Navy and Air Force. The Tri-Service Laser Radar (TSLR) produces pixel-registered range, velocity, active signal intensity and passive thermal emission data. Fusion of the active and passive information allows for improved characterization and discrimination between manmade objects and natural background clutter. Simple feature synergy of the pixel-registered active and passive infor-mation also provides robust cues for wire detection algorithms.

Nettleton, J. E.; Fox, C. S.; Rohde, R. S.; Buser, R. G.

1989-12-01

163

Passive-solar construction handbook  

SciTech Connect

Many of the basic elements of passive solar design are reviewed. Passive solar construction is covered according to system type, each system type discussion including a general discussion of the important design and construction issues which apply to the particular system and case studies illustrating designed and built examples of the system type. The three basic types of passive solar systems discussed are direct gain, thermal storage wall, and attached sunspace. Thermal performance and construction information is presented for typical materials used in passive solar collector components, storage components, and control components. Appended are an overview of analysis methods and a technique for estimating performance. (LEW)

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

1981-02-01

164

Fly ash carbon passivation  

DOEpatents

A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

La Count, Robert B; Baltrus, John P; Kern, Douglas G

2013-05-14

165

Passive Dynamic Biped Catalogue, 1991  

Microsoft Academic Search

Passive dynamic bipeds walk and run by virtue of physics inherent in the interaction of their legs and the ground; they need no motor control. A diverse spectrum of passive models are now known; together they offer a lively repertoire, including locomotion at various speeds, up and down hills, in two and three dimensions, and over unevenly-spaced footholds. We review

Tad Mcgeer

1991-01-01

166

Passive Greenhouses and Ecological Reconstruction  

Microsoft Academic Search

This paper is discussing the ecological reconstruction opportunity opened by the extended use of the energetic passive greenhouses, independent of any conventional infrastructure (water, gas, electricity). A specific passive greenhouse configuration is considered: the main heating device is a heat pump extracting energy from cold underground water. A dc wind generator is supplying the small amount of energy necessary for

V. E. Balas; M. M. Balas; M. V. Putin-Racovita

2008-01-01

167

Passive retrofits for Navy housing  

SciTech Connect

A project to assess and initiate passive solar energy retrofits to US Navy family housing is described. The current data base for Navy housing (ECOP), and its enhancement for passive solar purposes options proposed for Navy housing are explained. The analysis goals and methods to evaluate the retrofits are discussed. An educational package to explain the retrofits is described.

Hibbert, R.; Miles, C.; Jones, R.; Peck, C.; Anderson, J.; Jacobson, V.; Dale, A.M.

1985-01-01

168

Temperature initiated passive cooling system  

DOEpatents

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 temperature.

Forsberg, Charles W. (Oak Ridge, TN)

1994-01-01

169

6, 54275456, 2006 Passive microwave  

E-print Network

ACPD 6, 5427­5456, 2006 Passive microwave 3-D polarization effects from rainy clouds A. Battaglia in polarization signatures as observed from precipitating clouds by low frequency ground-based microwave, 5427­5456, 2006 Passive microwave 3-D polarization effects from rainy clouds A. Battaglia et al. Title

Boyer, Edmond

170

Passive Optical Networks (PONs)  

NSDL National Science Digital Library

Gordon and Mike's ICT Podcast offers perspectives on the information and communication technologies (ICT) industries from Gordon Snyder and Mike Qaissaunee. In this podcast, Mike and Gordon take a look at modern day fiber optics delivery systems. The conversation focuses on innovations in the fiber optics industry. Some of these include passive optical networks, fiber P2P networks, and centralized/distributed/cascading splitting choices. The podcast concludes with a question whether or not technicians are âÂÂtypically terminating fiber in the field.â In addition to this, the authors provide a question by question transcript and references to enhance the experience. Running time for the show is 24:24.

Qaissaunee, Michael; Snyder, Gordon F.

2010-11-23

171

Passive Ball Capture Joint  

NASA Technical Reports Server (NTRS)

A passive ball capture joint has a sleeve with a plurality of bores distributed about a circumference thereof and formed therethrough at an acute angle relative to the sleeve's longitudinal axis. A spring-loaded retainer is slidingly fitted in each bore and is biased such that, if allowed, will extend at least partially into the sleeve to retain a ball therein. A ring, rotatably mounted about the bores, has an interior wall defining a plurality of shaped races that bear against the spring-loaded retainers. A mechanized rotational force producer is coupled to the ring. The ring can be rotated from a first position (that presses the retainers into the sleeve to lock the ball in place) to a second position (that allows the retainers to springback out of the sleeve to release the ball).

Cloyd, Richard A. (Inventor); Bryan, Thomas C. (Inventor)

2003-01-01

172

Antireflection/Passivation Step For Silicon Cell  

NASA Technical Reports Server (NTRS)

New process excludes usual silicon oxide passivation. Changes in principal electrical parameters during two kinds of processing suggest antireflection treatment almost as effective as oxide treatment in passivating cells. Does so without disadvantages of SiOx passivation.

Crotty, Gerald T.; Kachare, Akaram H.; Daud, Taher

1988-01-01

173

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

174

Passive Vaporizing Heat Sink  

NASA Technical Reports Server (NTRS)

A passive vaporizing heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a pressure-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The vapor of the liquid escapes when the temperature exceeds the boiling point corresponding to the vapor pressure determined by the setting of the pressure-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of vaporization, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.

Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.

2011-01-01

175

Expansion-based passive ranging  

NASA Technical Reports Server (NTRS)

This paper describes a new technique of passive ranging which is based on utilizing the image-plane expansion experienced by every object as its distance from the sensor decreases. This technique belongs in the feature/object-based family. The motion and shape of a small window, assumed to be fully contained inside the boundaries of some object, is approximated by an affine transformation. The parameters of the transformation matrix are derived by initially comparing successive images, and progressively increasing the image time separation so as to achieve much larger triangulation baseline than currently possible. Depth is directly derived from the expansion part of the transformation. To a first approximation, image-plane expansion is independent of image-plane location with respect to the focus of expansion (FOE) and of platform maneuvers. Thus, an expansion-based method has the potential of providing a reliable range in the difficult image area around the FOE. In areas far from the FOE the shift parameters of the affine transformation can provide more accurate depth information than the expansion alone, and can thus be used similarly to the way they have been used in conjunction with the Inertial Navigation Unit (INU) and Kalman filtering. However, the performance of a shift-based algorithm, when the shifts are derived from the affine transformation, would be much improved compared to current algorithms because the shifts--as well as the other parameters--can be obtained between widely separated images. Thus, the main advantage of this new approach is that, allowing the tracked window to expand and rotate, in addition to moving laterally, enables one to correlate images over a very long time span which, in turn, translates into a large spatial baseline resulting in a proportionately higher depth accuracy.

Barniv, Yair

1993-01-01

176

Expansion-based passive ranging  

NASA Technical Reports Server (NTRS)

A new technique of passive ranging which is based on utilizing the image-plane expansion experienced by every object as its distance from the sensor decreases is described. This technique belongs in the feature/object-based family. The motion and shape of a small window, assumed to be fully contained inside the boundaries of some object, is approximated by an affine transformation. The parameters of the transformation matrix are derived by initially comparing successive images, and progressively increasing the image time separation so as to achieve much larger triangulation baseline than currently possible. Depth is directly derived from the expansion part of the transformation. To a first approximation, image-plane expansion is independent of image-plane location with respect to the focus of expansion (FOE) and of platform maneuvers. Thus, an expansion-based method has the potential of providing a reliable range in the difficult image area around the FOE. In areas far from the FOE the shift parameters of the affine transformation can provide more accurate depth information than the expansion alone, and can thus be used similarly to the way they were used in conjunction with the Inertial Navigation Unit (INU) and Kalman filtering. However, the performance of a shift-based algorithm, when the shifts are derived from the affine transformation, would be much improved compared to current algorithms because the shifts - as well as the other parameters - can be obtained between widely separated images. Thus, the main advantage of this new approach is that, allowing the tracked window to expand and rotate, in addition to moving laterally, enables one to correlate images over a very long time span which, in turn, translates into a large spatial baseline - resulting in a proportionately higher depth accuracy.

Barniv, Yair

1993-01-01

177

Passive Solar Is Common Sense.  

ERIC Educational Resources Information Center

A checklist of concepts concerning passive solar energy techniques. Many can be applied immediately to existing buildings, while others should be brought into the initial planning of buildings. (Author/MLF)

Robison, Rita

1979-01-01

178

Differences and similarities in the serotonergic diathesis for suicide attempts and mood disorders: a 22-year longitudinal gene-environment study.  

PubMed

To investigate similarities and differences in the serotonergic diathesis for mood disorders and suicide attempts, we conducted a study in a cohort followed longitudinally for 22 years. A total of 1255 members of this cohort, which is representative of the French-speaking population of Quebec, were investigated. Main outcome measures included (1) mood disorders (bipolar disorder and major depression) and suicide attempts by early adulthood; (2) odds ratios and probabilities associated with 143 single nucleotide polymorphisms in 11 serotonergic genes, acting directly or as moderators in gene-environment interactions with childhood sexual or childhood physical abuse (CPA), and in gene-gene interactions; (3) regression coefficients for putative endophenotypes for mood disorders (childhood anxiousness) and suicide attempts (childhood disruptiveness). Five genes showed significant adjusted effects (HTR2A, TPH1, HTR5A, SLC6A4 and HTR1A). Of these, HTR2A variation influenced both suicide attempts and mood disorders, although through different mechanisms. In suicide attempts, HTR2A variants (rs6561333, rs7997012 and rs1885884) were involved through interactions with histories of sexual and physical abuse whereas in mood disorders through one main effect (rs9316235). In terms of phenotype-specific contributions, TPH1 variation (rs10488683) was relevant only in the diathesis for suicide attempts. Three genes contributed exclusively to mood disorders, one through a main effect (HTR5A (rs1657268)) and two through gene-environment interactions with CPA (HTR1A (rs878567) and SLC6A4 (rs3794808)). Childhood anxiousness did not mediate the effects of HTR2A and HTR5A on mood disorders, nor did childhood disruptiveness mediate the effects of TPH1 on suicide attempts. Of the serotonergic genes implicated in mood disorders and suicidal behaviors, four exhibited phenotype-specific effects, suggesting that despite their high concordance and common genetic determinants, suicide attempts and mood disorders may also have partially independent etiological pathways. To identify where these pathways diverge, we need to understand the differential, phenotype-specific gene-environment interactions such as the ones observed in the present study, using suitably powered samples. PMID:19381154

Brezo, J; Bureau, A; Mérette, C; Jomphe, V; Barker, E D; Vitaro, F; Hébert, M; Carbonneau, R; Tremblay, R E; Turecki, G

2010-08-01

179

Galaxy Zoo: passive red spirals  

Microsoft Academic Search

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

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

2010-01-01

180

Passive vapor extraction feasibility study  

SciTech Connect

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.-diameter pipe, a check valve, a canister filled with granular activated carbon, and a wind turbine. The check valve will prevent inflow of air that otherwise would dilute the soil gas and make its subsequent extraction less efficient. The granular activated carbon is used to adsorb the carbon tetrachloride from the air. The wind turbine enhances extraction rates on windy days. Passive vapor extraction units will be designed and operated to meet all applicable or relevant and appropriate requirements. Based on a cost analysis, passive vapor extraction was found to be a cost-effective method for remediation of soils containing lower concentrations of volatile contaminants. Passive vapor extraction used on wells that average 10-stdft{sup 3}/min air flow rates was found to be more cost effective than active vapor extraction for concentrations below 500 parts per million by volume (ppm) of carbon tetrachloride. For wells that average 5-stdft{sup 3}/min air flow rates, passive vapor extraction is more cost effective below 100 ppm.

Rohay, V.J.

1994-06-30

181

Estimating Risks and Relative Risks in Case-Base Studies under the Assumptions of Gene-Environment Independence and Hardy-Weinberg Equilibrium  

PubMed Central

Many diseases result from the interactions between genes and the environment. An efficient method has been proposed for a case-control study to estimate the genetic and environmental main effects and their interactions, which exploits the assumptions of gene-environment independence and Hardy-Weinberg equilibrium. To estimate the absolute and relative risks, one needs to resort to an alternative design: the case-base study. In this paper, the authors show how to analyze a case-base study under the above dual assumptions. This approach is based on a conditional logistic regression of case-counterfactual controls matched data. It can be easily fitted with readily available statistical packages. When the dual assumptions are met, the method is approximately unbiased and has adequate coverage probabilities for confidence intervals. It also results in smaller variances and shorter confidence intervals as compared with a previous method for a case-base study which imposes neither assumption. PMID:25137392

Chui, Tina Tsz-Ting; Lee, Wen-Chung

2014-01-01

182

Empirical Hierarchical Bayes Approach to Gene-Environment Interactions: Development and Application to Genome-Wide Association Studies of Lung Cancer in TRICL  

PubMed Central

The analysis of gene-environment (GxE) interactions remains one of the greatest challenges in the post-genome-wide-association-studies (GWAS) era. Recent methods constitute a compromise between the robust but underpowered case-control and powerful case-only methods. Inferences of the latter are biased when the assumption of gene-environment (G-E) independence fails. We propose a novel empirical hierarchical Bayes approach to GxE interaction (EHB-GE), which benefits from greater power while accounting for population-based G-E dependence. Building on Lewinger et al.'s ([2007] Genet Epidemiol 31:871-882) hierarchical Bayes prioritization approach, the method utilizes posterior G-E association estimates in controls based on G-E information across the genome to adjust for it in resulting test statistics. These posteriori estimates are subtracted from the corresponding G-E association coefficients within cases. We compared EHB-GE with rival methods using simulation. EHB-GE has similar or greater rank power to detect GxE interactions in the presence of large numbers of G-E associations with weak to strong effects or only a low number of such associations with large effect. When there are no or only a few weak G-E associations, Murcray et al.'s method ([2009] Am J Epidemiol 169:219-226) identifies markers with low GxE interaction effects better. We applied EHB-GE and competing methods to four lung cancer case-control GWAS from the TRICL/ILCCO consortium with smoking as environmental factor. Genes identified by the EHB-GE approach are reasonable candidates, suggesting usefulness of the method. PMID:23893921

Amos, Christopher I.; Brennan, Paul; Fehringer, Gord; Gaborieau, Valerie; Han, Younghun; Heinrich, Joachim; Chang-Claude, Jenny; Hung, Rayjean J.; Muller-Nurasyid, Martina; Risch, Angela; Thomas, Duncan; Bickeboller, Heike

2014-01-01

183

Evidence of gene-environment interaction for the IRF6 gene and maternal multivitamin supplementation in controlling the risk of cleft lip with/without cleft palate  

PubMed Central

Although multiple genes have been identified as genetic risk factors for isolated, non-syndromic cleft lip with/without cleft palate (CL/P), a complex and heterogeneous birth defect, interferon regulatory factor 6 gene (IRF6) is one of the best documented genetic risk factors. In this study, we tested for association between markers in IRF6 and CL/P in 326 Chinese case–parent trios, considering gene–environment interaction for two common maternal exposures, and parent-of-origin effects. CL/P case–parent trios from three sites in mainland China and Taiwan were genotyped for 22 single nucleotide polymorphisms (SNPs) in IRF6. The transmission disequilibrium test was used to test for marginal effects of individual SNPs. We used PBAT to screen the SNPs and haplotypes for gene–environment (G × E) interaction and conditional logistic regression models to quantify effect sizes for SNP–environment interaction. After Bonferroni correction, 14 SNPs showed statistically significant association with CL/P. Evidence of G × E interaction was found for both maternal exposures, multivitamin supplementation and environmental tobacco smoke (ETS). Two SNPs showed evidence of interaction with multivitamin supplementation in conditional logistic regression models (rs2076153 nominal P = 0.019, rs17015218 nominal P = 0.012). In addition, rs1044516 yielded evidence for interaction with maternal ETS (nominal P = 0.041). Haplotype analysis using PBAT also suggested interaction between SNPs in IRF6 and both multivitamin supplementation and ETS. However, no evidence for maternal genotypic effects or significant parent-of-origin effects was seen in these data. These results suggest IRF6 gene may influence risk of CL/P through interaction with multivitamin supplementation and ETS in the Chinese population. PMID:20652317

Wu, Tao; Liang, Kung Yee; Hetmanski, Jacqueline B.; Ruczinski, Ingo; Fallin, Margaret Daniele; Ingersoll, Roxann G.; Wang, Hong; Huang, Shangzhi; Ye, Xiaoqian; Wu-Chou, Yah-Huei; Chen, Philip K.; Jabs, Ethylin W.; Shi, Bing; Redett, Richard; Scott, Alan F.

2010-01-01

184

Microgravity Passive Phase Separator  

NASA Technical Reports Server (NTRS)

A new invention disclosure discusses a structure and process for separating gas from liquids in microgravity. The Microgravity Passive Phase Separator consists of two concentric, pleated, woven stainless- steel screens (25-micrometer nominal pore) with an axial inlet, and an annular outlet between both screens (see figure). Water enters at one end of the center screen at high velocity, eventually passing through the inner screen and out through the annular exit. As gas is introduced into the flow stream, the drag force exerted on the bubble pushes it downstream until flow stagnation or until it reaches an equilibrium point between the surface tension holding bubble to the screen and the drag force. Gas bubbles of a given size will form a front that is moved further down the length of the inner screen with increasing velocity. As more bubbles are added, the front location will remain fixed, but additional bubbles will move to the end of the unit, eventually coming to rest in the large cavity between the unit housing and the outer screen (storage area). Owing to the small size of the pores and the hydrophilic nature of the screen material, gas does not pass through the screen and is retained within the unit for emptying during ground processing. If debris is picked up on the screen, the area closest to the inlet will become clogged, so high-velocity flow will persist farther down the length of the center screen, pushing the bubble front further from the inlet of the inner screen. It is desired to keep the velocity high enough so that, for any bubble size, an area of clean screen exists between the bubbles and the debris. The primary benefits of this innovation are the lack of any need for additional power, strip gas, or location for venting the separated gas. As the unit contains no membrane, the transport fluid will not be lost due to evaporation in the process of gas separation. Separation is performed with relatively low pressure drop based on the large surface area of the separating screen. Additionally, there are no moving parts, and there are no failure modes that involve fluid loss. A patent application has been filed.

Paragano, Matthew; Indoe, William; Darmetko, Jeffrey

2012-01-01

185

Synthetic passive margin stratigraphy  

SciTech Connect

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 that the rate of erosion is a dominant variable in determining the type of stratigraphic section observed. The proposed approach may provide the basis for either a forward or inverse modeling of seismic stratigraphic sections.

Turcotte, D.L.; Kenyon, P.M.

1984-06-01

186

Multivariate Dimensionality Reduction Approaches to Identify Gene-Gene and Gene-Environment Interactions Underlying Multiple Complex Traits  

PubMed Central

The elusive but ubiquitous multifactor interactions represent a stumbling block that urgently needs to be removed in searching for determinants involved in human complex diseases. The dimensionality reduction approaches are a promising tool for this task. Many complex diseases exhibit composite syndromes required to be measured in a cluster of clinical traits with varying correlations and/or are inherently longitudinal in nature (changing over time and measured dynamically at multiple time points). A multivariate approach for detecting interactions is thus greatly needed on the purposes of handling a multifaceted phenotype and longitudinal data, as well as improving statistical power for multiple significance testing via a two-stage testing procedure that involves a multivariate analysis for grouped phenotypes followed by univariate analysis for the phenotypes in the significant group(s). In this article, we propose a multivariate extension of generalized multifactor dimensionality reduction (GMDR) based on multivariate generalized linear, multivariate quasi-likelihood and generalized estimating equations models. Simulations and real data analysis for the cohort from the Study of Addiction: Genetics and Environment are performed to investigate the properties and performance of the proposed method, as compared with the univariate method. The results suggest that the proposed multivariate GMDR substantially boosts statistical power. PMID:25259584

Xu, Hai-Ming; Sun, Xi-Wei; Qi, Ting; Lin, Wan-Yu; Liu, Nianjun; Lou, Xiang-Yang

2014-01-01

187

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. PMID:22714405

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

2012-01-01

188

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

189

Passive solar energy in buildings  

SciTech Connect

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 are also applicable to sophisticated modern buildings like offices and schools, for example to cut down on fossil fuel usage. An authoritative assessment of the potential for utilizing passive solar energy is ser out in six sections. Domestic dwellings, offices, and industrial, retail and service buildings are all covered.

O'Sullivan, P. (Welsh School of Architecture, UWIST, Cardiff (US))

1988-01-01

190

Gene-environment interaction between body mass index and transforming growth factor beta 1 (TGF?1) gene in knee and hip osteoarthritis  

PubMed Central

Introduction The objective was to investigate potential gene-environment interaction between body mass index (BMI) and each of eight TGF?1 polymorphisms in knee and hip osteoarthritis (OA). Methods We conducted a case-control study of Caucasian men and women aged 45 to 86 years from Nottingham, United Kingdom (Genetics of OA and Lifestyle (GOAL) study). Cases had clinically severe symptoms and radiographic knee or hip OA; controls had no symptoms and no radiographic knee/hip OA. We used logistic regression to investigate the association of TGF?1 polymorphisms and OA when stratifying by BMI. Knee and hip OA were analyzed separately with adjustment for potential confounders. Additive and multiplicative interactions were examined. Results 2,048 cases (1,042 knee OA, 1,006 hip OA) and 967 controls were studied. For hip OA, the highest risk was in overweight (BMI ?25 kg/m2) individuals with the variant allele of single-nucleotide polymorphism (SNP) rs1800468 (odds ratio (OR) 2.21, 95% confidence interval (CI) 1.55, 3.15). Evaluation of gene-environment interaction indicated significant synergetic interaction (relative excess risk due to interaction (RERI) = 0.93, synergy index (SI) = 4.33) with an attributable proportion due to interaction (AP) of 42% (AP = 0.42; 95% CI 0.16, 0.68). Multiplicative interaction was also significant (OR for interaction (ORINT) = 2.27, P = 0.015). For knee OA, the highest risk was in overweight individuals with homozygous genotype 11 of SNP rs2278422 (OR = 6.95, P <0.001). In contrast, the variant allele indicated slightly lower risks (OR = 4.72, P <0.001), a significant antagonistic interaction (RERI = -2.66, SI = 0.59), AP = -0.56 (95%CI -0.94, -0.17) and a significant multiplicative interaction (ORINT = 0.47, P = 0.013). Conclusion TGF?1 gene polymorphisms interact with being overweight to influence the risk of large joint OA. PMID:23597094

2013-01-01

191

Passive infrared motion sensing technology  

Microsoft Academic Search

In the last 10 years passive IR based (8 to 12 microns) motion sensing has matured to become the dominant method of volumetric space protection and surveillance. These systems currently cost less than $25 to produce and yet use traditionally expensive IR optics, filters, sensors, and electronic circuitry. This IR application is quite interesting in that the volumes of systems

Alan P

1994-01-01

192

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

193

Monitored passive-solar buildings  

NASA Astrophysics Data System (ADS)

Selected performance results from six monitored passive and hybrid solar heated buildings are presented. These employ: a two story trombe wall; a thermosyphoning solar air heater with rock bin storage; a greenhouse; a composite concrete and water trombe wall; two story sunspace; and, for a mobile/modular home, direct gain and roof pond.

Jones, R. W.

1982-06-01

194

Passive propulsion in vortex wakes  

Microsoft Academic Search

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

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

2006-01-01

195

Passive margins through earth history  

NASA Astrophysics Data System (ADS)

Passive margins have existed somewhere on Earth almost continually since 2740 Ma. They were abundant at 1900-1890, 610-520, and 150-0 Ma, scarce at ca. 2445-2300, 1600-1000, and 300-275 Ma, and absent before ca. 3000 Ma and at 1740-1600. The fluctuations in abundance of passive margins track the first-order fluctuations of the independently derived seawater 87Sr/ 86Sr secular curve, and the compilation thus appears to be robust. The 76 ancient passive margins for which lifespans could be measured have a mean lifespan of 181 m.y. The world-record holder, with a lifespan of 590 m.y., is the Mesoproterozoic eastern margin of the Siberian craton. Subdivided into natural age groups, mean lifespans are 186 m.y. for the Archean to Paleoproterozoic, 394 m.y. for the Mesoproterozoic, 180 m.y. for the Neoproterozoic, 137 m.y. for the Cambrian to Carboniferous, and 130 m.y. for the Permian to Neogene. The present-day passive margins, which are not yet finished with their lifespans, have a mean age of 104 m.y. and a maximum age of 180 m.y. On average, Precambrian margins thus had longer, not shorter, lifespans than Phanerozoic ones—and this remains the case even discounting all post-300 Ma margins, most of which have time left. Longer lifespans deeper in the past is at odds with the widely held notion that the tempo of plate tectonics was faster in the Precambrian than at present. It is entirely consistent, however, with recent modeling by Korenaga [Korenaga, J., 2004. Archean geodynamics and thermal evolution of Earth. Archean Geodynamics and Environments, AGU Geophysical Monograph Series 164, 7-32], which showed that plate tectonics was more sluggish in the Precambrian. The abundance of passive margins clearly tracks the assembly, tenure, and breakup of Pangea. Earlier parts of the hypothesized supercontinent cycle, however, are only partly consistent with the documented abundance of passive margins. The passive-margin record is not obviously consistent with the proposed breakup of Nuna (Columbia), the assembly of Rodinia, or the assembly or breakup of the putative Pannotia. An alternative model is put forth involving (a) formation of two or more supercratons during the late Paleoproterozoic, (b) a Mesoproterozoic interval dominated by lateral accretion of arcs rather than by continental breakup and dispersal, (c) wholesale collision to form Rodinia by the end of the Mesoproterozoic, and (d) staged breakup of Rodinia through much of the Neoproterozoic.

Bradley, Dwight C.

2008-12-01

196

Simple tool for the design of passive solar buildings  

SciTech Connect

The design tools that are presently available for use by designers of passive solar heating or cooling systems include detailed simulation codes, correlations derived from the detailed codes, and simulations that may be used for short term analyses using programmable handheld calculators or deak-top computers. An alternative method is based on classical frequency response techniques and yields results that are in close agreement with those that are obtained from detailed computer simulations. 13 refs.

Winn, C.B.

1981-01-01

197

Temporal processing of active and passive head movement  

Microsoft Academic Search

The brain can know about an active head movement even in advance of its execution by means of an efference copy signal. In\\u000a fact, sensory correlates of active movements appear to be suppressed. Passive disturbances of the head, however, can be detected\\u000a only by sensory feedback. Might the perceived timing of an active head movement be speeded relative to the

Michael Barnett-CowanLaurence; Laurence R. Harris

198

Citric Acid Passivation of Stainless Steel.  

National Technical Information Service (NTIS)

Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nit...

C. Carl, C. Larson, D. Yasensky, J. Reali

2010-01-01

199

HCI gesture tracking using wearable passive tags  

E-print Network

In this thesis. a wearable system is developed to track hand gestures with passive RFID sensor tags. This system was composed of an ultra-high frequency reader and small, passive, finger-worn tags powered by scavenged RFID ...

Bainbridge, Rachel M

2010-01-01

200

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 Central

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; Yee, Kung; Liang; 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.

2013-01-01

201

Testing for measured gene-environment interaction: problems with the use of cross-product terms and a regression model reparameterization solution.  

PubMed

The study of gene-environment interaction (G × E) has garnered widespread attention. The most common way to assess interaction effects is in a regression model with a G × E interaction term that is a product of the values specified for the genotypic (G) and environmental (E) variables. In this paper we discuss the circumstances under which interaction can be modeled as a product term and cases in which use of a product term is inappropriate and may lead to erroneous conclusions about the presence and nature of interaction effects. In the case of a binary coded genetic variant (as used in dominant and recessive models, or where the minor allele occurs so infrequently that it is not observed in the homozygous state), the regression coefficient corresponding to a significant interaction term reflects a slope difference between the two genotype categories and appropriately characterizes the statistical interaction between the genetic and environmental variables. However, when using a three-category polymorphic genotype, as is commonly done when modeling an additive effect, both false positive and false negative results can occur, and the nature of the interaction can be misrepresented. We present a reparameterized regression equation that accurately captures interaction effects without the constraints imposed by modeling interactions using a single cross-product term. In addition, we provide a series of recommendations for making conclusions about the presence of meaningful G × E interactions, which take into account the nature of the observed interactions and whether they map onto sensible genotypic models. PMID:24531874

Aliev, Fazil; Latendresse, Shawn J; Bacanu, Silviu-Alin; Neale, Michael C; Dick, Danielle M

2014-03-01

202

The Genesis 12-19 (G1219) Study: a twin and sibling study of gene-environment interplay and adolescent development in the UK.  

PubMed

The Genesis 12-19 (G1219) Study is an ongoing longitudinal study of a sample of UK twin pairs, non-twin sibling pairs, and their parents. G1219 was initially designed to examine the role of gene-environment interplay in adolescent depression. However, since then data have continued to be collected from both parents and their offspring into young adulthood. This has allowed for longitudinal analyses of depression and has enabled researchers to investigate multiple phenotypes and to ask questions about intermediate mechanisms. The study has primarily focused on emotional development, particularly depression and anxiety, which have been assessed at multiple levels of analysis (symptoms, cognitions, and relevant environmental experiences). G1219 has also included assessment of a broader range of psychological phenotypes ranging from antisocial behaviors and substance use to sleep difficulties, in addition to multiple aspects of the environment. DNA has also been collected. The first wave of data collection began in the year 1999 and the fifth wave of data collection will be complete before the end of 2012. In this article, we describe the sample, data collection, and measures used. We also summarize some of the key findings to date. PMID:23394190

McAdams, Tom A; Gregory, Alice M; Rowe, Richard; Zavos, Helena M S; Barclay, Nicola L; Lau, Jennifer Y F; Maughan, Barbara; Eley, Thalia C

2013-02-01

203

Phenotypic effects of repeated psychosocial stress during adolescence in mice mutant for the schizophrenia risk gene neuregulin-1: a putative model of gene × environment interaction.  

PubMed

There is a paucity of animal models by which the contributions of environmental and genetic factors to the pathobiology of psychosis can be investigated. This study examined the individual and combined effects of chronic social stress during adolescence and deletion of the schizophrenia risk gene neuregulin-1 (NRG1) on adult mouse phenotype. Mice were exposed to repeated social defeat stress during adolescence and assessed for exploratory behaviour, working memory, sucrose preference, social behaviour and prepulse inhibition in adulthood. Thereafter, in vitro cytokine responses to mitogen stimulation and corticosterone inhibition were assayed in spleen cells, with measurement of cytokine and brain-derived neurotrophic factor (BDNF) mRNA in frontal cortex, hippocampus and striatum. NRG1 mutants exhibited hyperactivity, decreased anxiety, impaired sensorimotor gating and reduced preference for social novelty. The effects of stress on exploratory/anxiety-related parameters, spatial working memory, sucrose preference and basal cytokine levels were modified by NRG1 deletion. Stress also exerted varied effect on spleen cytokine response to concanavalin A and brain cytokine and BDNF mRNA expression in NRG1 mutants. The experience of psychosocial stress during adolescence may trigger further pathobiological features that contribute to the development of schizophrenia, particularly in those with underlying NRG1 gene abnormalities. This model elaborates the importance of gene × environment interactions in the etiology of schizophrenia. PMID:22426432

Desbonnet, Lieve; O'Tuathaigh, Colm; Clarke, Gerard; O'Leary, Claire; Petit, Emilie; Clarke, Niamh; Tighe, Orna; Lai, Donna; Harvey, Richard; Cryan, John F; Dinan, Timothy G; Waddington, John L

2012-05-01

204

Effects of divorce on Dutch boys' and girls' externalizing behavior in Gene × Environment perspective: diathesis stress or differential susceptibility in the Dutch Tracking Adolescents' Individual Lives Survey study?  

PubMed

The effects of divorce on children's behavioral development have proven to be quite varied across studies, and most developmental and family scholars today appreciate the great heterogeneity in divorce effects. Thus, this inquiry sought to determine whether select dopaminergic genes previously associated with externalizing behavior and/or found to moderate diverse environmental effects (dopamine receptors D2 and D4, catechol-O-methyltransferase) might moderate divorce effects on adolescent self-reported externalizing problems; and, if so, whether evidence of gene-environment (G × E) interaction would prove consistent with diathesis-stress or differential-susceptibility models of environmental action. Data from the first and third wave of the Dutch Tracking Adolescents' Individual Lives Survey (n = 1,134) revealed some evidence of G × E interaction reflecting diathesis-stress but not differential susceptibility. It is intriguing that some evidence pointed to "vantage sensitivity," which are benefits accruing to those with a specific genotype when their parents remained together, the exact opposite of diathesis-stress. The limits of this work are considered, especially with regard to the conditions for testing differential susceptibility, and future directions are outlined. PMID:22781863

Nederhof, Esther; Belsky, Jay; Ormel, Johan; Oldehinkel, Albertine J

2012-08-01

205

Dietary habit profile in European communities with different risk of myocardial infarction: the impact of migration as a model of gene-environment interaction. The IMMIDIET Study.  

PubMed

The risk of myocardial infarction (MI) is lower in southern than in northern European countries. The lower rate of MI in the Mediterranean regions of Europe suggested a potential role of the traditional Mediterranean diet in the prevention of MI. Unfortunately, in the last 20 years, a tendency to adopt Westernised food habits even in southern regions of Europe is reflected by an increase in the prevalence of obesity. Therefore the impact of diet on MI risk profile among European populations needs to be reconsidered. Genetic risk factors have also been implicated in the development of MI. Genes, indeed, continuously interact with environmental factors in determining the pathogenesis of MI. The aims of the IMMIDIET study are to evaluate: 1. The present dietary habits and the risk profile of three European communities at different risk of MI; 2. The impact of migration on risk factors for MI. Dietary habits and genetic polymorphisms will be evaluated in an Italian, Belgian and British population sample. The historical Italian migration to Belgium and the integration through mixed marriage will be considered as a model of gene-environment interaction. As an index of MI risk profile, factors that are most likely under the combined influence of both dietary and genetic determinants will be investigated. PMID:11894745

Iacoviello, L; Arnout, J; Buntinx, F; Cappuccio, F P; Dagnelie, P C; de Lorgeril, M; Dirckx, C; Donati, M B; Krogh, V; Siani, A

2001-08-01

206

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. PMID:23226953

Chaste, Pauline; Leboyer, Marion

2012-01-01

207

Multidimensional passive sampled Port-Hamiltonian systems  

Microsoft Academic Search

Passivity of virtual environments running in discrete time is a sufficient condition for stability of the system. The framework for passive sampled Port-Hamiltonian systems allows multi-dimensional virtual environments exhibiting internal dynamic behavior to be computed on a discrete medium in a passive manner. It is shown that a causality analysis is required in the framework to detect if any of

Michel Franken; Rob Reilink; Sarthak Misra; Stefano Stramigioli

2010-01-01

208

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

209

Development of Verbal Passive in Williams Syndrome  

ERIC Educational Resources Information Center

Purpose: To experimentally investigate knowledge of passives of actional ("hold") and psychological ("love") verbs in children with Williams syndrome (WS). Passives are usually reported to be in line with mental age in WS. However, studies usually focus on passives of actional verbs only. Method: Twenty-six children with WS, ages 6-16, and 3…

Perovic, Alexandra; Wexler, Kenneth

2010-01-01

210

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

211

Passive control techniques in earthquake engineering  

Microsoft Academic Search

Significant progress has been made in the development of passive control techniques in earthquake (EQ) engineering during the last two decades. Today, the most successful passive structural control technique in earthquake engineering is base isolation. Following the successful history of implementation of base isolation technology, passive energy dissipation devices are currently making inroads. In this paper a simple comparison of

Simon Kim

1995-01-01

212

Influence of meteorological factors on the atmospheric mercury measurement by a novel passive sampler  

NASA Astrophysics Data System (ADS)

In recent years, an incentive for developing simple and cost-effective samplers that are capable of monitoring over an extended period and require nonattendance at remote locations was obvious. Compared to traditional active sampling approaches, passive samplers require no electric power and are more flexible in field deployment, thus they are more appropriate for screening applications and long-term sampling. However, the performance of passive samplers may be influenced by meteorological factors, therefore inducing bias for the result of passive sampling. In this study, the effects of temperature, relative humidity, and wind speed on the performance of a novel passive sampler for gaseous mercury were investigated. The meteorological factors were well controlled in an exposure chamber. The passive samplers were tested in different conditions: temperature ranging from -10 to 35 °C, relative humidity ranging from 25 to 90%, wind speed ranging from 0.5 to 5.0 m s-1. The results showed that temperature and relative humidity had no significant influence on the performance of the passive sampler. However, wind speed was found to have significant impact on the sampling rate of the passive sampler. Wind correction should be considered when making comparisons among samplings with different average wind speeds. In the field application in Beijing and Tibet site, the passively measured data were well correlated with the active measurements.

Guo, Haoli; Lin, Huiming; Zhang, Wei; Deng, Chunyan; Wang, Huanhuan; Zhang, Qianggong; Shen, Yating; Wang, Xuejun

2014-11-01

213

Passive standoff detection of chemical warfare agents on surfaces.  

PubMed

Results are presented on the passive standoff detection and identification of chemical warfare (CW) liquid agents on surfaces by the Fourier-transform IR radiometry. This study was performed during surface contamination trials at Defence Research and Development Canada-Suffield in September 2002. The goal was to verify that passive long-wave IR spectrometric sensors can potentially remotely detect surfaces contaminated with CW agents. The passive sensor, the Compact Atmospheric Sounding Interferometer, was used in the trial to obtain laboratory and field measurements of CW liquid agents, HD and VX. The agents were applied to high-reflectivity surfaces of aluminum, low-reflectivity surfaces of Mylar, and several other materials including an armored personnel carrier. The field measurements were obtained at a standoff distance of 60 m from the target surfaces. Results indicate that liquid contaminant agents deposited on high-reflectivity surfaces can be detected, identified, and possibly quantified with passive sensors. For low-reflectivity surfaces the presence of the contaminants can usually be detected; however, their identification based on simple correlations with the absorption spectrum of the pure contaminant is not possible. PMID:15540446

Thériault, Jean-Marc; Puckrin, Eldon; Hancock, Jim; Lecavalier, Pierre; Lepage, Carmela Jackson; Jensen, James O

2004-11-01

214

Genes, environment, and cardiovascular disease.  

PubMed

In this essay, we call to attention what every medical researcher knows about the etiology of cardiovascular disease but most deny, or choose to ignore, when designing, carrying out, and reporting genetic studies. Medical research is entering an era of synthesis that will take advantage of the successes of reductionism over the past decade in defining and describing human genome variations. Meaningful insights into the role of such variation requires a biological model of genome-phenotype relationships that incorporates interactions between subsets of possible genetic and environmental agents as causations in particular contexts indexed by time and space. We make recommendations for what needs to be done to cope with these complexities. PMID:12730090

Sing, Charles F; Stengård, Jari H; Kardia, Sharon L R

2003-07-01

215

Myths in passive solar design  

SciTech Connect

For years passive solar design principles have been perpetuated without being reexamined or questioned regarding their relevance in the context of new materials and constructions. Rarely does an architect get quantitative feedback on system or concept performance after the building is built. The result has been the perpetuation of beliefs among conference papers, text books and popular articles, all too often based only on belief. In this paper examples of premises which likely deserve to be kept passive rather than acted on are challenged. Designers are encouraged to ask three questions when applying a commonly held rule or assumption: Does it address the right issue? Does it apply, given the properties of new components and materials? If the premise is violated, how badly is comfort or the energy balance affected? Examples taken from monitoring and sensitivity studies illustrate the importance of asking `stupid` questions. 9 refs., 5 figs.

Hastings, S.R. [Swiss Federal Inst. of Technology, Zuerich (Switzerland)] [Swiss Federal Inst. of Technology, Zuerich (Switzerland)

1995-12-31

216

Workshop 1: Passive solar systems  

NASA Astrophysics Data System (ADS)

The design of a solar house for a latitude of 50 degrees north in Northern Europe is discussed. An evaluation of a 500 cubic meter house and a computerized simulation of a 350 cubic meter house are given. It was found that the heating demand of a poorly insulated house may be decreased by 70 to 75% by means of an extensive insulation; new buildings should be extensively insulated; passive solar energy utilization is usually not cost effective.

Schneider, M.; Schreitmueller, K. R.

1982-11-01

217

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

218

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

219

Serum carboxymethyllysine, an advanced glycation end product, and age-related macular degeneration: the Age, Gene/Environment Susceptibility-Reykjavik Study.  

PubMed

IMPORTANCE Advanced glycation end products have been implicated in the pathogenesis of age-related macular degeneration (AMD). OBJECTIVE To investigate the relationship between serum carboxymethyllysine (CML), a major circulating advanced glycation end product, and AMD in older adults. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study of a population-based sample of 4907 older adults (aged ?66 years) in the Age, Gene/Environment Susceptibility-Reykjavik Study in Iceland. EXPOSURES Serum CML and risk factors for AMD. MAIN OUTCOMES AND MEASURES Early or late AMD, assessed through fundus images taken through dilated pupils using a 45° digital camera and grading for drusen size, type, area, increased retinal pigment, retinal pigment epithelial depigmentation, neovascular lesions, and geographic atrophy using the modified Wisconsin Age-Related Maculopathy Grading System. RESULTS Of the 4907 participants, 1025 (20.9%) had early AMD and 276 (5.6%) had late AMD. Mean (SD) serum CML concentrations among adults with no AMD, early AMD, and late AMD (exudative AMD and pure geographic atrophy) were 618.8 (195.5), 634.2 (206.4), and 638.4 (192.0) ng/mL, respectively (to convert to micromoles per liter, multiply by 0.00489; P?=?.07). Log serum CML (per 1-SD increase) was not associated with any AMD (early and late AMD) (odds ratio?=?0.97; 95% CI, 0.90-1.04; P?=?.44) or with late AMD (odds ratio?=?0.94; 95% CI, 0.82-1.08; P?=?.36) in respective multivariable logistic regression models adjusting for age, sex, body mass index, smoking, and renal function. CONCLUSIONS AND RELEVANCE Higher serum CML concentration had no significant cross-sectional association with prevalent AMD in this large population-based cohort of older adults in Iceland. PMID:24481410

Semba, Richard D; Cotch, Mary Frances; Gudnason, Vilmundur; Eiríksdottir, Gudny; Harris, Tamara B; Sun, Kai; Klein, Ronald; Jonasson, Fridbert; Ferrucci, Luigi; Schaumberg, Debra A

2014-04-01

220

Evidence of gene-environment interaction for two genes on chromosome 4 and environmental tobacco smoke in controlling the risk of nonsyndromic cleft palate.  

PubMed

Nonsyndromic cleft palate (CP) is one of the most common human birth defects and both genetic and environmental risk factors contribute to its etiology. We conducted a genome-wide association study (GWAS) using 550 CP case-parent trios ascertained in an international consortium. Stratified analysis among trios with different ancestries was performed to test for GxE interactions with common maternal exposures using conditional logistic regression models. While no single nucleotide polymorphism (SNP) achieved genome-wide significance when considered alone, markers in SLC2A9 and the neighboring WDR1 on chromosome 4p16.1 gave suggestive evidence of gene-environment interaction with environmental tobacco smoke (ETS) among 259 Asian trios when the models included a term for GxE interaction. Multiple SNPs in these two genes were associated with increased risk of nonsyndromic CP if the mother was exposed to ETS during the peri-conceptual period (3 months prior to conception through the first trimester). When maternal ETS was considered, fifteen of 135 SNPs mapping to SLC2A9 and 9 of 59 SNPs in WDR1 gave P values approaching genome-wide significance (10(-6)

Wu, Tao; Schwender, Holger; Ruczinski, Ingo; Murray, Jeffrey C; Marazita, Mary L; Munger, Ronald G; Hetmanski, Jacqueline B; Parker, Margaret M; Wang, Ping; Murray, Tanda; Taub, Margaret; Li, Shuai; Redett, Richard J; Fallin, M Daniele; Liang, Kung Yee; Wu-Chou, Yah Huei; Chong, Samuel S; Yeow, Vincent; Ye, Xiaoqian; Wang, Hong; Huang, Shangzhi; Jabs, Ethylin W; Shi, Bing; Wilcox, Allen J; Jee, Sun Ha; Scott, Alan F; Beaty, Terri H

2014-01-01

221

Evidence of Gene-Environment Interaction for Two Genes on Chromosome 4 and Environmental Tobacco Smoke in Controlling the Risk of Nonsyndromic Cleft Palate  

PubMed Central

Nonsyndromic cleft palate (CP) is one of the most common human birth defects and both genetic and environmental risk factors contribute to its etiology. We conducted a genome-wide association study (GWAS) using 550 CP case-parent trios ascertained in an international consortium. Stratified analysis among trios with different ancestries was performed to test for GxE interactions with common maternal exposures using conditional logistic regression models. While no single nucleotide polymorphism (SNP) achieved genome-wide significance when considered alone, markers in SLC2A9 and the neighboring WDR1 on chromosome 4p16.1 gave suggestive evidence of gene-environment interaction with environmental tobacco smoke (ETS) among 259 Asian trios when the models included a term for GxE interaction. Multiple SNPs in these two genes were associated with increased risk of nonsyndromic CP if the mother was exposed to ETS during the peri-conceptual period (3 months prior to conception through the first trimester). When maternal ETS was considered, fifteen of 135 SNPs mapping to SLC2A9 and 9 of 59 SNPs in WDR1 gave P values approaching genome-wide significance (10?6

Wu, Tao; Schwender, Holger; Ruczinski, Ingo; Murray, Jeffrey C.; Marazita, Mary L.; Munger, Ronald G.; Hetmanski, Jacqueline B.; Parker, Margaret M.; Wang, Ping; Murray, Tanda; Taub, Margaret; Li, Shuai; Redett, Richard J.; Fallin, M. Daniele; Liang, Kung Yee; Wu-Chou, Yah Huei; Chong, Samuel S.; Yeow, Vincent; Ye, Xiaoqian; Wang, Hong; Huang, Shangzhi; Jabs, Ethylin W.; Shi, Bing; Wilcox, Allen J.; Jee, Sun Ha; Scott, Alan F.; Beaty, Terri H.

2014-01-01

222

Family-based study of HTR2A in suicide attempts: observed gene, gene × environment and parent-of-origin associations.  

PubMed

While suicidal behavior is frequently accompanied by serotonergic system alterations, specific associations with genetic variation in the serotonin 2A receptor (HTR2A) gene have been inconsistent. Using a family-based study design of 660 offspring who have made a suicide attempt (SA) and both parents, we conducted an association and linkage analysis using single-nucleotide polymorphisms (SNPs) with extensive gene coverage, and included the study of parent-of-origin (POE) and gene-environment interaction (G × E), also using previously unstudied exposures. The main finding was a G × E between the exon 1 SNP rs6313 and exposure to cumulative types of lifetime stressful life events (SLEs), driven by overtransmission of CT and undertransmission of TT, both in relation to other genotypes. Further exploratory analysis revealed a significant POE in this G × E in female subjects, which followed a polar overdominant inheritance pattern. In addition, rs6310 and rs6305 were found to significantly associate with SA in the total sample. A G × E in female subjects (rs7322347 × physical assault in childhood/adolescence) confirmed features of a previously observed association with SA. Other potentially interesting nominally significant findings were observed, but like the G × E of rs7322347 did not pass a false-discovery rate cutoff. Taken together, this study found multiple associations of HTR2A SNPs on SA, with strongest statistical evidence for a G × E involving rs6313, and further suggested the importance of taking into account different inheritance patterns and G × Es with regard to HTR2A. PMID:22751492

Ben-Efraim, Y J; Wasserman, D; Wasserman, J; Sokolowski, M

2013-07-01

223

A neural switch for active and passive fear.  

PubMed

The central nucleus of the amygdala (CeA) serves as a major output of this structure and plays a critical role in the expression of conditioned fear. By combining cell- and tissue-specific pharmacogenetic inhibition with functional magnetic resonance imaging (fMRI), we identified circuits downstream of CeA that control fear expression in mice. Selective inhibition of a subset of neurons in CeA led to decreased conditioned freezing behavior and increased cortical arousal as visualized by fMRI. Correlation analysis of fMRI signals identified functional connectivity between CeA, cholinergic forebrain nuclei, and activated cortical structures, and cortical arousal was blocked by cholinergic antagonists. Importantly, inhibition of these neurons switched behavioral responses to the fear stimulus from passive to active responses. Our findings identify a neural circuit in CeA that biases fear responses toward either passive or active coping strategies. PMID:20797541

Gozzi, Alessandro; Jain, Apar; Giovannelli, Aldo; Giovanelli, Aldo; Bertollini, Cristina; Crestan, Valerio; Schwarz, Adam J; Tsetsenis, Theodoros; Ragozzino, Davide; Gross, Cornelius T; Bifone, Angelo

2010-08-26

224

Passive solar: economics and ethics  

SciTech Connect

The economic feasibility of passive solar for space heating is examined. The key finding is that from the standpoint of society the costs of substitutes have been badly understated. The major source of error is valuing at average rather than replacement costs, using steady state furnace efficiencies, and failing to adjust for government subsidies in the production of fossil fuels. This provides a basis for explaining the failure of the market and individual choice. The issue of corrective policy is explained briefly from the standpoint of efficiency and ethical criteria.

Duffield, J.

1980-01-01

225

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

226

Passive mitigation of mode instabilities  

NASA Astrophysics Data System (ADS)

The phenomenon of mode instabilities has quickly become the most limiting effect for a further scaling of the average power of fiber laser systems. Consequently it is of great importance to find solutions for this problem. In this work we propose two concrete possible passive mitigation strategies: the first one is based on the reduction of the heat load in the fiber, whereas the second one is based on the reduction of the pump absorption. In both cases a significant increase of the threshold is expected.

Jauregui, C.; Otto, H.-J.; Stutzki, F.; Jansen, F.; Limpert, J.; Tünnermann, A.

2014-03-01

227

Passive solar in China: traditional and new  

SciTech Connect

The authors' observations of a tradition of passive solar architecture in northern China are described. Tendencies for modern buildings to depart from this tradition are noted. Major passive solar research programs are discussed and experimental buildings are illustrated. It is concluded that the Chinese could realize a major advantage by combining their strong tradition of passive solar architecture with modern insulation methods and improved glazing systems.

Balcomb, J.D.; Balcomb, S.A.

1986-04-01

228

The Future of Passive Solar in Industry  

E-print Network

THE FUTURE OF PASSIVE SOLAR IN INDUSTRY Donald R. WUlfingh9ff, P.E. WUlfinghoff Energy Services, Inc. Wheaton, Maryland ABSTRACT Passive solar is a family of tech niques for the direct use of sunlight for illumination and heating.... Industrial facilities have characteristics which particularly favor the use of these tech niques. This paper examines the applic ability and economic potential of passive solar in the industrial environment, and offers specific suggestions for achieving...

Wulfinghoff, D. R.

229

Cellular automaton formulation of passive scalar dynamics  

NASA Technical Reports Server (NTRS)

Cellular automata modeling of the advection of a passive scalar in a two-dimensional flow is examined in the context of discrete lattice kinetic theory. It is shown that if the passive scalar is represented by tagging or 'coloring' automation particles a passive advection-diffusion equation emerges without use of perturbation expansions. For the specific case of the hydrodynamic lattice gas model of Frisch et al. (1986), the diffusion coefficient is calculated by perturbation.

Chen, Hudong; Matthaeus, William H.

1987-01-01

230

Effects of Isokinetic Passive Exercise and Isometric Muscle Contraction on Passive Stiffness  

PubMed Central

[Purpose] The purpose of this study was to investigate the effects of isokinetic passive exercise and motion velocity on passive stiffness. In addition, we also discuss the effects of the contraction of agonist and antagonist muscles on passive stiffness. [Subjects] The subjects were 20 healthy men with no bone or joint disease. [Methods] Isokinetic passive exercise and isometric muscle contraction were performed on an isokinetic dynamometer. The angular acceleration measured by the accelerometer was compared before and after each task. [Results] After the passive exercise, the angular acceleration increased in the phase of small damped oscillation. Moreover, the effect was higher at high-speed movement. The angular acceleration was decreased by the contraction of the agonist muscle. Conversely, the angular acceleration was increased by the contraction of the antagonist muscle. [Conclusion] Isokinetic passive exercise reduced passive stiffness. Our results suggest the possibility that passive stiffness is increased by agonist muscle contraction and decreased by antagonist muscle contraction. PMID:24259791

Terada, Shigeru; Miaki, Hiroichi; Uchiyama, Keita; Hayakawa, Shozo; Yamazaki, Toshiaki

2013-01-01

231

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.

232

Passive electroreception in aquatic mammals.  

PubMed

Passive electroreception is a sensory modality in many aquatic vertebrates, predominantly fishes. Using passive electroreception, the animal can detect and analyze electric fields in its environment. Most electric fields in the environment are of biogenic origin, often produced by prey items. These electric fields can be relatively strong and can be a highly valuable source of information for a predator, as underlined by the fact that electroreception has evolved multiple times independently. The only mammals that possess electroreception are the platypus (Ornithorhynchus anatinus) and the echidnas (Tachyglossidae) from the monotreme order, and, recently discovered, the Guiana dolphin (Sotalia guianensis) from the cetacean order. Here we review the morphology, function and origin of the electroreceptors in the two aquatic species, the platypus and the Guiana dolphin. The morphology shows certain similarities, also similar to ampullary electroreceptors in fishes, that provide cues for the search for electroreceptors in more vertebrate and invertebrate species. The function of these organs appears to be very similar. Both species search for prey animals in low-visibility conditions or while digging in the substrate, and sensory thresholds are within one order of magnitude. The electroreceptors in both species are innervated by the trigeminal nerve. The origin of the accessory structures, however, is completely different; electroreceptors in the platypus have developed from skin glands, in the Guiana dolphin, from the vibrissal system. PMID:23187861

Czech-Damal, Nicole U; Dehnhardt, Guido; Manger, Paul; Hanke, Wolf

2013-06-01

233

General Corrosion and Passive Film Stability  

SciTech Connect

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 solution compositions representing the products of both the evaporation of seepage water and also the deliquescence of dust previously deposited on the waste canisters. These data represent the first weight-loss measurements performed by the program at temperatures above 90 C. The low corrosion rates of Alloy 22 are attributed to the protective oxide film that forms at the metal surface. In this report, changes in the oxide film composition are correlated with weight loss at the higher temperatures (140-220 C) where film characterization had not been previously performed. The stability of the oxide film was further analyzed by conducting a series of electrochemical tests in progressively more acidic solutions to measure the general corrosion rates in solutions that mimic crevice or pit environments.

Orme, C; Gray, J; Hayes, J; Wong, L; Rebak, R; Carroll, S; Harper, J; Gdowski, G

2005-07-19

234

Condensation model for the ESBWR passive condensers  

SciTech Connect

In the General Electric's Economic simplified boiling water reactor (GE-ESBWR) the passive containment cooling system (PCCS) plays a major role in containment pressure control in case of an loss of coolant accident. The PCCS condenser must be able to remove sufficient energy from the reactor containment to prevent containment from exceeding its design pressure following a design basis accident. There are three PCCS condensation modes depending on the containment pressurization due to coolant discharge; complete condensation, cyclic venting and flow through mode. The present work reviews the models and presents model predictive capability along with comparison with existing data from separate effects test. The condensation models in thermal hydraulics code RELAP5 are also assessed to examine its application to various flow modes of condensation. The default model in the code predicts complete condensation well, and basically is Nusselt solution. The UCB model predicts through flow well. None of condensation model in RELAP5 predict complete condensation, cyclic venting, and through flow condensation consistently. New condensation correlations are given that accurately predict all three modes of PCCS condensation. (authors)

Revankar, S. T. [Pohang Univ. of Science and Technology, 400 Central Drive, West Lafayette, IN 47906 (United States); Zhou, W.; Wolf, B.; Oh, S. [Purdue Univ., West Lafayette, IN 47906 (United States)

2012-07-01

235

Characterization of tetraethylene glycol passivated iron nanoparticles  

NASA Astrophysics Data System (ADS)

The present study describes the synthesis and characterization of iron@iron oxide nanoparticles produced by passivation of metallic iron in tetraethylene glycol media. Structural and chemical characterizations were performed using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Mössbauer spectroscopy. Pomegranate-like core@shell nanoparticulate material in the size range of 90-120 nm was obtained. According to quantitative phase analysis using Rietveld structure refinement the synthesized iron oxide was identified as magnetite (Fe3O4) whereas the iron to magnetite mass fractions was found to be 47:53. These findings are in good agreement with the data obtained from Mössbauer and thermal gravimetric analysis (TGA). The XPS data revealed the presence of a surface organic layer with higher hydrocarbon content, possibly due to the tetraethylene glycol thermal degradation correlated with iron oxidation. The room-temperature (300 K) saturation magnetization measured for the as-synthesized iron and for the iron-iron oxide were 145 emu g-1 and 131 emu g-1, respectively. The measured saturation magnetizations are in good agreement with data obtained from TEM, XRD and Mössbauer spectroscopy.

Nunes, Eloiza da Silva; Viali, Wesley Renato; da Silva, Sebastião William; Coaquira, José Antonio Huamaní; Garg, Vijayendra Kumar; de Oliveira, Aderbal Carlos; Morais, Paulo César; Jafelicci Júnior, Miguel

2014-10-01

236

Development of integrated passives QFN package  

Microsoft Academic Search

Integration of passives or discrete components is advantageous for end-customers in the simplification of their board design, board space-saving and overall cost reduction. The paper will discuss the development of integrating passives within a QFN package for an integrated power management solution. It is quickly found that placing together multiple components of varied dimensions and properties, pose challenges to manufacturability

Edwin Lim Jin Keong

2011-01-01

237

Cues for Understanding the Passive Voice.  

ERIC Educational Resources Information Center

Two experiments were conducted on the use and combination of three cues that differentiate active from passive verbs: a form of the auxiliary "be," the morphology of the passive participle of the verb, and the case-making preposition "by." In the first experiment, 59 children aged 2.9 to 5.10 years were asked to interpret sentences with one, two,…

Stromswold, Karin; And Others

1985-01-01

238

Strong local passivity in finite quantum systems.  

PubMed

Passive states of quantum systems are states from which no system energy can be extracted by any cyclic (unitary) process. Gibbs states of all temperatures are passive. Strong local (SL) passive states are defined to allow any general quantum operation, but the operation is required to be local, being applied only to a specific subsystem. Any mixture of eigenstates in a system-dependent neighborhood of a nondegenerate entangled ground state is found to be SL passive. In particular, Gibbs states are SL passive with respect to a subsystem only at or below a critical system-dependent temperature. SL passivity is associated in many-body systems with the presence of ground state entanglement in a way suggestive of collective quantum phenomena such as quantum phase transitions, superconductivity, and the quantum Hall effect. The presence of SL passivity is detailed for some simple spin systems where it is found that SL passivity is neither confined to systems of only a few particles nor limited to the near vicinity of the ground state. PMID:25122271

Frey, Michael; Funo, Ken; Hotta, Masahiro

2014-07-01

239

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...

240

Passive electronic sensors in military operations  

Microsoft Academic Search

The use of passive electronic sensors in military operations and electronic warfare development are discussed. The advantages of electronic support measures regarding radar are pointed out, and passive and active electronic countermeasures such as jamming and deception are discussed; also considered are electronic counter-countermeasures such as antijamming, antianalysis and antideception. In addition, attention is given to ground-air operations in Vietnam,

R. Mastrofilippo

1980-01-01

241

Reclaiming the Passive-Aggressive Youth  

ERIC Educational Resources Information Center

Few children can control adult emotions more effectively than passive-aggressive youngsters. Their passive lack of compliance can incite even trained professionals to employ ineffective punitive responses. These responses confirm for the child the unreasonable and hurtful nature of adults. In this Life Space Crisis Intervention, the child makes a…

Marquoit, James W.

2004-01-01

242

Passive Identification and Analysis of TCP Anomalies  

E-print Network

and time, which is due to the closed-loop behavior of TCP, the TCP/IP client- server communication paradigmPassive Identification and Analysis of TCP Anomalies Marco Mellia, Michela Meo, Luca Muscariello on passive measurements of TCP traffic, main component of nowadays traffic. We propose a heuristic technique

243

Passive Solar Construction--Design and Performance.  

ERIC Educational Resources Information Center

Presented is a list of books and reports intended to serve as technical sources of information for the building professional interested in energy conservation. These publications are grouped under these headings: (1) energy-conserving building design; (2) passive systems/design; (3) passive systems/performance; and (4) proceedings (of the American…

Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

244

Passive Sampling of Atmospheric Photochemical Oxidants  

Microsoft Academic Search

A simple, cost-effective passive sampler is described that is suitable for measuring parts per billion (ppb) levels of photochemical oxidants (ozone + nitrogen dioxide + peroxyacetyl nitrate + peroxypropionyl nitrate) in ambient air. The passive sampler makes use of oxidant-fugitive colorants, and color changes are proportional to the oxidant dose, i.e. the product of oxidant concentration and sampling duration. Field

D. Grosjean; E. L. Williams Ii; E. Grosjean

1992-01-01

245

Lagrangian velocity correlations in homogeneous isotropic turbulence  

SciTech Connect

The Lagrangian velocity autocorrelation and the time correlations for individual wave-number bands are computed by direct numerical simulation (DNS) using the passive vector method (PVM), and the accuracy of the method is studied. It is found that the PVM is accurate when [ital K][sub max]/[ital k][sub [ital d

Gotoh, T. (Center for Turbulence Research, Stanford University, Stanford, California 94305-3030 (United States)); Rogallo, R.S. (NASA-Ames Research Center, Moffett Field, California 94035 (United States)); Herring, J.R. (National Center for Atmospheric Research, P.O. Box 3000, Boulder, Colorado 80307 (United States)); Kraichnan, R.H. (369 Montezuma 108, Santa Fe, New Mexico 87501 (United States))

1993-11-01

246

A Passive Magnetic Bearing Flywheel  

NASA Technical Reports Server (NTRS)

A 100 percent passive magnetic bearing flywheel rig employing no active control components was designed, constructed, and tested. The suspension clothe rotor was provided by two sets of radial permanent magnetic bearings operating in the repulsive mode. The axial support was provided by jewel bearings on both ends of the rotor. The rig was successfully operated to speeds of 5500 rpm, which is 65 percent above the first critical speed of 3336 rpm. Operation was not continued beyond this point because of the excessive noise generated by the air impeller and because of inadequate containment in case of failure. Radial and axial stiffnesses of the permanent magnetic bearings were experimentally measured and then compared to finite element results. The natural damping of the rotor was measured and a damping coefficient was calculated.

Siebert, Mark; Ebihara, Ben; Jansen, Ralph; Fusaro, Robert L.; Morales, Wilfredo; Kascak, Albert; Kenny, Andrew

2002-01-01

247

Passive Tracking System and Method  

NASA Technical Reports Server (NTRS)

System and methods are disclosed for passively determining the location of a moveable transmitter utilizing a pair of phase shifts at a receiver for extracting a direction vector from a receiver to the transmitter. In a preferred embodiment, a phase difference between the transmitter and receiver is extracted utilizing a noncoherent demodulator in the receiver. The receiver includes antenna array with three antenna elements, which preferably are patch antenna elements placed apart by one-half wavelength. Three receiver channels are preferably utilized for simultaneously processing the received signal from each of the three antenna elements. Multipath transmission paths for each of the three receiver channels are indexed so that comparisons of the same multipath component are made for each of the three receiver channels. The phase difference for each received signal is determined by comparing only the magnitudes of received and stored modulation signals to determine a winning modulation symbol.

Arndt, G. Dickey (Inventor); Ngo, Phong H. (Inventor); Chen, Henry A. (Inventor); Phan, Chau T. (Inventor); Bourgeois, Brian A. (Inventor); Dusl, John (Inventor); Hill, Brent W. (Inventor)

2005-01-01

248

Passive Tracking System and Method  

NASA Technical Reports Server (NTRS)

Systems and methods are disclosed for passively determining the location of a moveable transmitter utilizing a pair of phase shifts at a receiver for extracting a direction vector from a receiver to the transmitter. In a preferred embodiment, a phase difference between the transmitter and receiver is extracted utilizing a noncoherent demodulator in the receiver. The receiver includes an antenna array with three antenna elements, which preferably are patch antenna elements spaced apart by one-half wavelength. Three receiver channels are preferably utilized for simultaneously processing the received signal from each of the three antenna elements. Multipath transmission paths for each of the three receiver channels are indexed so that comparisons of the same multipath component are made for each of the three receiver channels. The phase difference for each received signal is determined by comparing only the magnitudes of received and stored modulation signals to determine a winning modulation symbol.

Arndt, G. Dickey (Inventor); Ngo, Phong H. (Inventor); Chen, Henry A. (Inventor); Phan, Chau T. (Inventor); Bourgeois, Brian A. (Inventor); Dusl, Jon (Inventor); Hill, Brent W. (Inventor)

2003-01-01

249

Passive Optical Sample Assembly (POSA)  

NASA Technical Reports Server (NTRS)

A Passive Optical Sample Assembly (POSA) unit was mounted and flown in the cargo bay of the space shuttle Columbia during the first Orbital Flight Test (OFT-1). A similar unit was mounted in a different location in the cargo bay during the postflight operations. The samples in both POSA arrays were subjected to a series of optical and analytical measurements prior to delivery for installation in the cargo bay and after retrieval of the flight hardware. The final results of a comparison of the two series of measurements are presented. These STS-1 results are based on data obtained from only a portion of one of the ten Induced Environment Contamination Monitor instruments to be flown on several shuttle flights beginning with STS-2. These limited results do not indicate shuttle contamination levels in excess of those anticipated.

Linton, R. C.; Miller, E. R.; Susko, M.

1981-01-01

250

Addressing Passive Smoking in Children  

PubMed Central

Background A significant number of parents are unaware or unconvinced of the health consequences of passive smoking (PS) in children. Physicians could increase parental awareness by giving personal advice. Aim To evaluate the current practices of three Dutch health professions (paediatricians, youth health care physicians, and family physicians) regarding parental counselling for passive smoking (PS) in children. Methods All physicians (n?=?720) representing the three health professions in Limburg, the Netherlands, received an invitation to complete a self-administered electronic questionnaire including questions on their: sex, work experience, personal smoking habits, counselling practices and education regarding PS in children. Results The response rate was 34%. One tenth (11%) of the responding physicians always addressed PS in children, 32% often, 54% occasionally and 4% reported to never attend to it. The three health professions appeared comparable regarding their frequency of parental counselling for PS in children. Addressing PS was more likely when children had respiratory problems. Lack of time was the most frequently mentioned barrier, being very and somewhat applicable for respectively 14% and 43% of the physicians. One fourth of the responders had received postgraduate education about PS. Additionally, 49% of the responders who did not have any education about PS were interested in receiving it. Conclusions Physicians working in the paediatric field in Limburg, the Netherlands, could more frequently address PS in children with parents. Lack of time appeared to be the most mentioned barrier and physicians were more likely to counsel parents for PS in children with respiratory complaints/diseases. Finally, a need for more education on parental counselling for PS was expressed. PMID:24809443

Hutchinson, Sasha G.; Kuijlaars, Jennifer S.; Mesters, Ilse; Muris, Jean W. M.; van Schayck, Constant P.; Dompeling, Edward; Feron, Frans J. M.

2014-01-01

251

ACTIVE AND PASSIVE CONTRIBUTIONS TO JOINT KINETICS DURING WALKING IN OLDER ADULTS  

PubMed Central

The objectives of this study were to characterize the active and passive contributions to joint kinetics during walking in healthy young and older adults, and assess whether isokinetic ankle strength is associated with ankle power output during walking. Twenty healthy young (18–35 years) and 20 healthy older (65–85 years) adults participated in this study. We measured subject-specific passive-elastic joint moment-angle relationships in the lower extremity and tested maximum isokinetic ankle strength at 30deg/sec. Passive moment-angle relationships were used to estimate active and passive joint moment, power, and work quantities during walking at 80, 100, and 120% of preferred walking speed. There were no significant differences in walking speed, step length, or cadence between the older and young adults. However, the older adults produced significantly more net positive work at the hip but less net positive work at the ankle at all walking speeds. Passive contributions to hip and ankle work did not significantly differ between groups, inferring that the older adults generated the additional hip work actively. Maximum isokinetic ankle strength was significantly less in the older adults, and correlated with peak positive plantar-flexor power at both the preferred and fast walking speeds. The results of this study suggest that age-related shifts in joint kinetics do not arise as a result of increased passive hip joint stiffness, but seem to be reflected in plantar-flexor weakness. PMID:18420214

Silder, Amy; Heiderscheit, Bryan; Thelen, Darryl G.

2009-01-01

252

The influence of active and passive smoking on the cardiorespiratory fitness of adults  

PubMed Central

Background The aim of this study was to analyze the influence of active and passive smoking on cardiorespiratory responses in asymptomatic adults during a sub-maximal-exertion incremental test. Methods The participants (n = 43) were divided into three different groups: active smokers (n = 14; aged 36.5 ± 8 years), passive smokers (n = 14; aged 34.6 ± 11.9 years) and non-smokers (n = 15; aged 30 ± 8.1 years). They all answered the Test for Nicotine Dependence and underwent anthropometric evaluation, spirometry and ergospirometry according to the Bruce Treadmill Protocol. Results VO2max differed statistically between active and non-smokers groups (p < 0.001) and between non-smokers and passive group (p=0.022). However, there was no difference between the passive and active smokers groups (p=0.053). Negative and significant correlations occurred between VO2max and age (r = - 0.401, p = 0.044), percentage of body fat (r = - 0.429, p = 0.011), and waist circumference (WC) (r = - 0.382, p = 0.025). Conclusion VO2max was significantly higher in non-smokers compared to active smokers and passive smokers. However, the VO2max of passive smokers did not differ from active smokers. PMID:25009739

2014-01-01

253

Gene-environment interactions on the risk of esophageal cancer among Asian populations with the G48A polymorphism in the alcohol dehydrogenase-2 gene: a meta-analysis.  

PubMed

The aim of this study is to investigate the gene-environment interactions between the G48A polymorphism in the alcohol dehydrogenase-2 (ADH2) gene and environmental factors in determining the risk of esophageal cancer (EC). A literature search was conducted in the PubMed, Embase, Web of Science, Cochrane Library, and Google Scholar databases to indentify eligible studies published before November 1, 2013. We performed a meta-analysis of 18 case-control studies with a total of 8,906 EC patients and 13,712 controls. The overall analysis suggested that individuals with the GG genotype were associated with a 2.77-fold increased risk of EC, compared with carriers of the GA and AA genotypes. In a stratified analysis by ethnic group, Japanese, Mainland Chinese, and Taiwan Chinese with the GG genotype had a significantly higher risk of EC, compared with Thai and Iranian populations, indicating ethnic variance in EC susceptibility. An analysis of combined effect indicated that GG genotype of ADH2 G48A was associated with the highest risk of EC in heavy drinkers and smokers. A striking difference was found to exist between males and females, showing gender variance for the association between ADH2 G48A and EC risk. This meta-analysis shows that the GG genotype of ADH2 G48A may be associated with an increased risk of EC in Asian populations. In addition, significant gene-environment interactions were found. Heavy drinkers, smokers, and males with the GG genotype may have a higher EC risk. Thus, our results shed new light on the complex gene-environment interactions that exist between environmental factors and ADH2 G48A polymorphism in EC risk. PMID:24446180

Zhang, Long; Jiang, Yingjiu; Wu, Qingcheng; Li, Qiang; Chen, Dan; Xu, Ling; Zhang, Cheng; Zhang, Min; Ye, Ling

2014-05-01

254

Citric Acid Passivation of Stainless Steel  

NASA Technical Reports Server (NTRS)

Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nitric acid per year, and receives many parts from vendors who must also dispose of used nitric acid. Unfortunately, nitric acid presents health and environmental hazards. As a result, several recent industry studies have examined citric acid as an alternative. Implementing a citric acid-based passivation procedure would improve the health and environmental safety aspects of passivation process. However although there is a lack of published studies that conclusively prove citric acid is a technically sound passivation agent. In 2007, NASA's KSC Materials Advisory Working Group requested the evaluation of citric acid in place of nitric acid for passivation of parts at KSC. United Space Alliance Materials & Processes engineers have developed a three-phase test plan to evaluate citric acid as an alternative to nitric acid on three stainless steels commonly used at KSC: UNS S30400, S41000, and S17400. Phases 1 and 2 will produce an optimized citric acid treatment based on results from atmospheric exposure at NASA's Beach Corrosion Facility. Phase 3 will compare the optimized solution(s) with nitric acid treatments. If the results indicate that citric acid passivates as well or better than nitric acid, NASA intends to approve this method for parts used at the Kennedy Space Center.

Yasensky, David; Reali, John; Larson, Chris; Carl, Chad

2009-01-01

255

Effectiveness of passivation techniques on hydrogen desorption in a tritium environment  

NASA Astrophysics Data System (ADS)

Tritium is a radioactive isotope of hydrogen. It is used as a fuel in fusion reactors, a booster material in nuclear weapons and as a light source in commercial applications. When tritium is used in fusion reactors, and especially when used in the manufacture of nuclear weapons, purity is critical. For U.S. Department of Energy use, tritium is recycled by Savannah River Site in South Carolina and is processed to a minimum purity of 99.5%. For use elsewhere in the country, it must be shipped and stored, while maintaining the highest purity possible. As an isotope of hydrogen it exchanges easily with the most common isotope of hydrogen, protium. Stainless steel bottles are used to transport and store tritium. Protium, present in air, becomes associated in and on the surface of stainless steel during and after the manufacture of the steel. When filled, the tritium within the bottle exchanges with the protium in and on the surface of the stainless steel, slowly contaminating the pure tritium with protium. The stainless steel is therefore passivated to minimize the protium outgrowth of the bottles into the pure tritium. This research is to determine how effective different passivation techniques are in minimizing the contamination of tritium with protium. Additionally, this research will attempt to determine a relationship between surface chemistry of passivated steels and protium contamination of tritium. The conclusions of this research found that passivated bottles by two companies which routinely provide passivated materials to the US Department of Energy provide low levels of protium outgrowth into pure tritium. A bottle passivated with a material to prevent excessive corrosion in a highly corrosive environment, and a clean and polished bottle provided outgrowth rates roughly twice those of the passivated bottles above. Beyond generally high levels of chromium, oxygen, iron and nickel in the passivated bottles, there did not appear to be a strong correlation between surface chemistry in the surface of the bottles and protium outgrowth rates.

Woodall, Steven Michael

256

Passive Smoking Impairs Histone Deacetylase-2 in Children With Severe Asthma  

PubMed Central

Background: Parental smoking is known to worsen asthma symptoms in children and to make them refractory to asthma treatment, but the molecular mechanism is unclear. Oxidative stress from tobacco smoke has been reported to impair histone deacetylase-2 (HDAC2) via phosphoinositide-3-kinase (PI3K)/Akt activation and, thus, to reduce corticosteroid sensitivity. The aim of this study was to investigate passive smoking-dependent molecular abnormalities in alveolar macrophages (AMs) by comparing passive smoke-exposed children and non-passive smoke-exposed children with uncontrolled severe asthma. Methods: BAL fluid (BALF) was obtained from 19 children with uncontrolled severe asthma (10 non-passive smoking-exposed subjects and nine passive smoking-exposed subjects), and HDAC2 expression/activity, Akt/HDAC2 phosphorylation levels, and corticosteroid responsiveness in AMs were evaluated. Results: Parental smoking reduced HDAC2 protein expression by 54% and activity by 47%, with concomitant enhancement of phosphorylation of Akt1 and HDAC2. In addition, phosphorylation levels of Akt1 correlated positively with HDAC2 phosphorylation levels and negatively with HDAC2 activity. Furthermore, passive smoke exposure reduced the inhibitory effects of dexamethasone on tumor necrosis factor-?-induced CXCL8 release in AMs. There were relatively higher neutrophil counts and CXCL8 concentrations in BALF and lower Asthma Control Test scores compared with non-passive smoke-exposed children with uncontrolled severe asthma. Conclusions: Passive smoking impairs HDAC2 function via PI3K signaling activation, which could contribute to corticosteroid-insensitive inflammation in children with severe asthma. This novel mechanism will be a treatment target in children with severe asthma and stresses the need for a smoke-free environment for asthmatic children. PMID:24030221

Kobayashi, Yoshiki; Bossley, Cara; Gupta, Atul; Akashi, Kenichi; Tsartsali, Lemonia; Mercado, Nicolas; Barnes, Peter J.; Bush, Andrew

2014-01-01

257

Passive smoking elevates neurotrophin levels in tears.  

PubMed

The effect of passive smoking on levels of neurotrophin in tears was studied in normal subjects or patients with atopic keratoconjunctivitis (AKC). Basal levels of neurotrophins, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and NT-4, in tears were significantly higher in AKC patients than those in normal subjects. Passive smoking had no effect on levels of neurotrophin in tears of normal subjects, while it elevated levels of NGF, BDNF, NT-3 and NT-4 in tears of AKC patients. These results indicate that passive smoking elevates levels of neurotrophin in tears, which in turn may aggravate AKC. PMID:15222398

Kimata, Hajime

2004-05-01

258

Passive Cooling of Body Armor  

NASA Astrophysics Data System (ADS)

Warfighter performance can be adversely affected by heat load and weight of equipment. Current tactical vest designs are good insulators and lack ventilation, thus do not provide effective management of metabolic heat generated. NRL has undertaken a systematic study of tactical vest thermal management, leading to physics-based strategies that provide improved cooling without undesirable consequences such as added weight, added electrical power requirements, or compromised protection. The approach is based on evaporative cooling of sweat produced by the wearer of the vest, in an air flow provided by ambient wind or ambulatory motion of the wearer. Using an approach including thermodynamic analysis, computational fluid dynamics modeling, air flow measurements of model ventilated vest architectures, and studies of the influence of fabric aerodynamic drag characteristics, materials and geometry were identified that optimize passive cooling of tactical vests. Specific architectural features of the vest design allow for optimal ventilation patterns, and selection of fabrics for vest construction optimize evaporation rates while reducing air flow resistance. Cooling rates consistent with the theoretical and modeling predictions were verified experimentally for 3D mockups.

Holtz, Ronald; Matic, Peter; Mott, David

2013-03-01

259

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

260

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.

Evans, Daniel J. (Wheeling, IL); Cha, Yung S. (Darien, IL)

1999-01-01

261

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

262

Passive environmental temperature control system  

DOEpatents

Passive environmental heating and cooling systems are described, which utilize heat pipes to transmit heat to or from a thermal reservoir. In a solar heating system, a heat pipe is utilized to carry heat from a solar heat absorber plate that receives sunlight, through a thermal insulation barrier, to a heat storage wall, with the outer end of the pipe which is in contact with the solar absorber being lower than the inner end. The inclining of the heat pipe assures that the portion of working fluid, such as Freon, which is in a liquid phase will fall by gravity to the outer end of the pipe, thereby assuring diode action that prevents the reverse transfer of heat from the reservoir to the outside on cool nights. In a cooling system, the outer end of the pipe which connects to a heat dissipator, is higher than the inner end that is coupled to a cold reservoir, to allow heat transfer only out of the reservoir to the heat dissipator, and not in the reverse direction.

Corliss, John M. (Columbus, OH); Stickford, George H. (Columbus, OH)

1981-01-01

263

Passively controlled supersonic cavity flow using a spanwise cylinder  

NASA Astrophysics Data System (ADS)

An experimental investigation of a passively controlled open cavity with a length to depth ratio of six and freestream Mach number of 1.4 was conducted to investigate the mechanisms responsible for the observed surface pressure reductions. The passive control comes from placing a spanwise aligned cylinder in the boundary layer near the leading edge of the cavity. The two control configurations were isolated from previous experiments of the fluctuating surface pressure and correspond to a larger diameter rod near the top of the boundary layer and a smaller diameter rod placed near the wall. These were further analyzed using particle image velocimetry in an attempt to elicit the responsible mechanism for the flow control. The use of two-point statistics revealed the wall normal turbulent velocity correlation's evolution became elongated in the wall normal direction. This suggests that the shear layer may be less-organized and consists of smaller-scale structures. The disturbance of the feedback receptivity loop is clearly demonstrated for the controlled configurations evidenced by weakened correlation signals between the aft wall sensor and positions on the cavity floor. The presence of the rod is shown to decrease the mean shear gradient, more effectively for the large rod placed at the top of the boundary layer, throughout the shear layer. The efficacy of the control leads to an initially thicker shear layer which spreads more rapidly and is clearly demonstrated by vorticity growth rates, mean, and turbulent flowfield statistics.

Dudley, Jonathan G.; Ukeiley, Lawrence

2014-09-01

264

Reliability of reflectance measures in passive filters  

NASA Astrophysics Data System (ADS)

Measurements of optical reflectance in passive filters impregnated with a reactive chemical solution may be transformed to ozone concentrations via a calibration curve and constitute a low cost alternative for environmental monitoring, mainly to estimate human exposure. Given the possibility of errors caused by exposure bias, it is common to consider sets of m filters exposed during a certain period to estimate the latent reflectance on n different sample occasions at a certain location. Mixed models with sample occasions as random effects are useful to analyze data obtained under such setups. The intra-class correlation coefficient of the mean of the m measurements is an indicator of the reliability of the latent reflectance estimates. Our objective is to determine m in order to obtain a pre-specified reliability of the estimates, taking possible outliers into account. To illustrate the procedure, we consider an experiment conducted at the Laboratory of Experimental Air Pollution, University of São Paulo, Brazil (LPAE/FMUSP), where sets of m = 3 filters were exposed during 7 days on n = 9 different occasions at a certain location. The results show that the reliability of the latent reflectance estimates for each occasion obtained under homoskedasticity is km = 0.74. A residual analysis suggests that the within-occasion variance for two of the occasions should be different from the others. A refined model with two within-occasion variance components was considered, yielding km = 0.56 for these occasions and km = 0.87 for the remaining ones. To guarantee that all estimates have a reliability of at least 80% we require measurements on m = 10 filters on each occasion.

Saldiva de André, Carmen Diva; Afonso de André, Paulo; Rocha, Francisco Marcelo; Saldiva, Paulo Hilário Nascimento; Carvalho de Oliveira, Regiani; Singer, Julio M.

2014-08-01

265

Correlation Introduction  

E-print Network

Correlation 43.2 Introduction While medical researchers might be interested in knowing, tests exist which allow us to interpret the meaning of a calculated correlation coefficient. 9 8 6 7 on a random error component say e and we have Y = mx + c + e In some situations, both X and Y are random

Vickers, James

266

Passive machine augmented composite for multifunctional properties  

E-print Network

This dissertation studies by experiment and numerical analysis an advanced composite material (Machine Augmented Composite or MAC) for enhancement of the passive damping while maintaining its stiffness. This MAC is composed of a pre-buckled wall...

Kim, Jong Hyun

2005-11-01

267

Comparison of active and passive FTIR  

NASA Astrophysics Data System (ADS)

This paper discusses the result of a field trial in which active and passive FTIRs measured plume concentration pathlength (CL). It will be shown that when the coadding duration of passive systems was the same as active systems, nearly identical CL values were obtained. At the field trial, plumes of SF6 were released. The release rate and duration were controlled using a flowmeter. All the FTIR systems were monitoring approximately the same spot in the plume. Weather station data and flowmeter data were used with a gaussian plume model to predict downwind CLs. The active CLs were determined with standard CLS processing. The passive CLs were determined by converting the passive spectra to radiometric spectra. From the radiometric spectra, the air temperature and background temperature were derived. With this information, the absorbance was calculated and the CL was determined from the absorbance peak of the chemical.

Gruber, Thomas C., Jr.; Grim, Larry B.; Ditillo, John T.

1998-08-01

268

Passive and active solar heating technology  

SciTech Connect

This source of information about solar heating technology examines both passive heating approaches, such as direct gain, Trombe wall, and sunspace systems, and active designs for heating buildings, water supplies, and swimming pools.

Meltzer, M.

1985-01-01

269

The Soil Moisture Active Passive (SMAP) Mission  

E-print Network

The Soil Moisture Active Passive (SMAP) mission is one of the first Earth observation satellites being developed by NASA in response to the National Research Council's Decadal Survey. SMAP will make global measurements of ...

Entekhabi, Dara

270

Market ecology of active and passive investors  

NASA Astrophysics Data System (ADS)

We study the role of active and passive investors in an investment market with uncertainties. Active investors concentrate on a single or a few stocks with a given probability of determining the quality of them. Passive investors spread their investment uniformly, resembling buying the market index. In this toy market stocks are introduced as good and bad. If a stock receives sufficient investment it will survive, otherwise die. Active players exert a selective pressure since they can determine to an extent the investment quality. We show that the active players provide the driving force, whereas the passive ones act as free riders. While their gains do not differ too much, we show that the active players enjoy an edge. Their presence also provides better gains to the passive players and stocks themselves.

Capocci, Andrea; Zhang, Yi-Cheng

2001-09-01

271

Passive Earth Entry Vehicle Energy Absorbing Systems  

NASA Astrophysics Data System (ADS)

A critical element of a passive EEV performance is the energy absorbing system required to attenuate the dynamic landing loads. Two design approaches are described and the pros and cons based on particular mission requirements are discussed.

Kellas, S.; Maddock, R. W.

2014-06-01

272

Interior planning of passive solar housing  

SciTech Connect

A study involving 28 Virginia passive solar homeowners was conducted in 1984 to examine their reactions to passive design. The results indicate that a significant source of dissatisfaction was in space planning; the majority of the homeowners had difficulty arranging furniture in the living room. The spatial analysis of the floor plans revealed that the configuration of the open plan and circulation as well as passive design features contributed to these space planning problems. Design guidelines and recommendations that incorporate the research findings are also presented. In terms of other considerations, these homeowners were very satisfied with their passive solar homes. This satisfaction seemed to be related to psychological factors; sunlight, spaciousness, and openness were frequently cited as the most pleasing elements of the designs.

McLain-Kark, J.

1987-01-01

273

Breast Cancer Risk, Fungicide Exposure and CYP1A1*2A Gene-Environment Interactions in a Province-Wide Case Control Study in Prince Edward Island, Canada  

PubMed Central

Scientific certainty regarding environmental toxin-related etiologies of breast cancer, particularly among women with genetic polymorphisms in estrogen metabolizing enzymes, is lacking. Fungicides have been recognized for their carcinogenic potential, yet there is a paucity of epidemiological studies examining the health risks of these agents. The association between agricultural fungicide exposure and breast cancer risk was examined in a secondary analysis of a province-wide breast cancer case-control study in Prince Edward Island (PEI) Canada. Specific objectives were: (1) to derive and examine the level of association between estimated fungicide exposures, and breast cancer risk among women in PEI; and (2) to assess the potential for gene-environment interactions between fungicide exposure and a CYP1A1 polymorphism in cases versus controls. After 1:3 matching of 207 cases to 621 controls by age, family history of breast cancer and menopausal status, fungicide exposure was not significantly associated with an increased risk of breast cancer (OR = 0.74; 95% CI: 0.46–1.17). Moreover, no statistically significant interactions between fungicide exposure and CYP1A1*2A were observed. Gene-environment interactions were identified. Though interpretations of findings are challenged by uncertainty of exposure assignment and small sample sizes, this study does provide grounds for further research. PMID:22754477

Ashley-Martin, Jillian; VanLeeuwen, John; Cribb, Alastair; Andreou, Pantelis; Guernsey, Judith Read

2012-01-01

274

Discreet passive explosive detection through 2-sided waveguided 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 (Stillwater, OK); la Grone, Marcus (Cushing, OK); Fisher, Mark (Stillwater, OK)

2011-10-18

275

Active versus passive proprioceptive straight-ahead pointing in normal subjects.  

PubMed

Eighty blindfolded healthy female subjects participated in an active and a passive straight-ahead pointing task to study the estimation of the subjective sagittal middle in the presence or absence of an active haptic exploration. Subjects were to point straight-ahead with their left or right index finger starting from different right- or left-sided locations, while performing either an active movement or with the hand being passively moved by the examiner. Results showed: (i) a significant effect of the hand used only on the active straight-ahead pointing task performance; (ii) a significant effect of the starting position both on the active and passive pointing performance; (iii) a significant correlation between the two protocols only in terms of spatial bias (algebraic error) but not in terms of precision (absolute errors). These results are discussed with regards to normal and neuropsychological studies of the egocentric frame of reference. PMID:15177798

Chokron, Sylvie; Colliot, Pascale; Atzeni, Thierry; Bartolomeo, Paolo; Ohlmann, Théophile

2004-07-01

276

Mesoscopics of ultrasound and seismic waves: application to passive imaging  

NASA Astrophysics Data System (ADS)

This manuscript deals with different aspects of the propagation of acoustic and seismic waves in heterogeneous media, both simply and multiply scattering ones. After a short introduction on conventional imaging techniques, we describe two observations that demonstrate the presence of multiple scattering in seismic records: the equipartition principle, and the coherent backscattering effect (Chap. 2). Multiple scattering is related to the mesoscopic nature of seismic and acoustic waves, and is a strong limitation for conventional techniques like medical or seismic imaging. In the following part of the manuscript (Chaps. 3 5), we present an application of mesoscopic physics to acoustic and seismic waves: the principle of passive imaging. By correlating records of ambient noise or diffuse waves obtained at two passive sensors, it is possible to reconstruct the impulse response of the medium as if a source was placed at one sensor. This provides the opportunity of doing acoustics and seismology without a source. Several aspects of this technique are presented here, starting with theoretical considerations and numerical simulations (Chaps. 3, 4). Then we present experimental applications (Chap. 5) to ultrasound (passive tomography of a layered medium) and to seismic waves (passive imaging of California, and the Moon, with micro-seismic noise). Physique mésoscopique des ultrasons et des ondes sismiques : application à l'imagerie passive. Cet article de revue rassemble plusieurs aspects fondamentaux et appliqués de la propagation des ondes acoustiques et élastiques dans les milieux hétérogènes, en régime de diffusion simple ou multiple. Après une introduction sur les techniques conventionelles d'imagerie sismique et ultrasonore, nous présentons deux expériences qui mettent en évidence la présence de diffusion multiple dans les enregistrements sismologiques : l'équipartition des ondes, et la rétrodiffusion cohérente (Chap. 2). La diffusion multiple des ondes, qui démontre l'aspect mésoscopique de leur propagation, est une limitation majeure pour les techniques d'imagerie conventionelles (imagerie médicale, sismique réflexion ou réfraction, tomographie...). La deuxième partie du document (Chaps. 3 5) est consacrée à une application de cette physique mésoscopique : le principe de l'imagerie passive. En effectuant la corrélation temporelle d'enregistrement de bruit ambiant ou d'ondes diffuses, il est possible de reconstruire la réponse impulsionnelle du milieu entre deux capteurs passifs comme si l'on avait placé une source en lieu et place d'un des capteurs. Cela offre la possibilité de faire de l'acoustique ou de la sismologie sans source. Plusieurs aspects sont présentés dans ce manuscrit : des aspects théoriques et numériques (Chaps. 3, 4), ensuite des aspects expérimentaux avec des applications (Chap. 5) à l'échelle des ultrasons (tomographie passive d'un milieu stratifié), et des applications à l'échelle de la sismologie (imagerie du sous-sol de la Californie, et même de la Lune).

Larose, É.

2006-05-01

277

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

278

Direct Control of a Passive Haptic Device Based on Passive Force Manipulability Ellipsoid Analysis  

Microsoft Academic Search

In displaying a virtual wall using a passive haptic device equipped with passive ac- tuators such as electric brakes, unsmooth motion frequently occurs. This undesirable behavior is attributed to time delay due to slowness in the virtual environment update and force ap- proximation due to the inability of a brake to generate torque in arbitrary directions. In this paper a

Changhyun Cho; Munsang Kim; Jae-Bok Song

2004-01-01

279

Effects of hydrogen on semiconductivity of passive films and corrosion behavior of 310 stainless steel  

SciTech Connect

The effects of hydrogen on the semiconductive properties and compositions of passive films on AISI 310 stainless steel (310 SS) and their corrosion behavior were investigated by Mott-Schottky plot, polarization, noise resistance analyses, and secondary ion mass spectrometry (SIMS). The results indicate that the susceptibility of 310 SS to pitting is strongly influenced by hydrogen present in the specimens. The conductivity type of the passive film formed at 0.7 V vs. saturated calomel electrode on the specimens charged with hydrogen at the quantity higher than 3.6 C cm{sup {minus}2} is p-type while that formed on the uncharged specimen is n-type, i.e., the presence of hydrogen in 310 SS causes an inversion of conductivity type of a surface film from p-type to n-type. When the concentration of ionized hydrogen in the passive film on the 310 SS, i.e., the donor density reaches the saturated value, the average content of the diffusible hydrogen released from a specimen measured by a U-tube filled with mercury under the condition of mechanical vacuum is 3.8 {times} 10{sup 20} cm{sup {minus}3}. The donor concentration evaluated from the Mott-Schottky slope is on the order of 10{sup 19} cm{sup {minus}3}. The susceptibility of 310 stainless steel (SS) to pitting can be correlated to the electronic properties and chemical compositions of the passive film. The high susceptibility of the charged specimens to pitting corresponds to the n-type conductivity of the passive film. While low susceptibility is connected to p-type conductivity and high content of chromium and nickel oxides. Such a correlation can be explained with the band model of a passive film.

Yang, M.Z.; Luo, J.L.; Yang, Q.; Qiao, L.J. [Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Chemical and Materials Engineering] [Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Chemical and Materials Engineering; Qin, Z.Q.; Norton, P.R. [Western Univ. of Western Ontario, London, Ontario (Canada). Dept. of Chemistry and Interface Science] [Western Univ. of Western Ontario, London, Ontario (Canada). Dept. of Chemistry and Interface Science

1999-06-01

280

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

281

Adaptive Interference Cancellation System with Different Correlation Control Methods  

Microsoft Academic Search

This paper investigates the correlation-integrator, correlation-lowpass and correlation-proportion control methods of an adaptive interference cancellation system (AICS). For a single channel AICS, the convergence characteristic of different control methods is gained and contrasted. The different functions of using active lowpass and passive lowpass are analyzed. The formulation of the changes of interference cancellation ratio (ICR) and convergence time with the

Yunhao Jiang; Weiming Ma; Zhihua Zhao

2009-01-01

282

Partitioning of organochlorine pesticides from water to polyethylene passive samplers.  

PubMed

The mass transfer rates and equilibrium partitioning behaviour of 14 diverse organochlorine pesticides (OCP) between water and polyethylene (PE) passive samplers, cut from custom made PE sheets and commercial polyethylene plastic bags, were quantified. Overall mass transfer coefficients, k(O), estimated PE membrane diffusion coefficients, D(PE), and PE-water partitioning coefficients, K(PE-water,) are reported. In addition, the partitioning of three polycyclic aromatic hydrocarbons (PAHs) from water to PE is quantified and compared with literature values. K(PE-water) values agreed mostly within a factor of two for both passive samplers and also with literature values for the reference PAHs. As PE is expected to exhibit similar sorption behaviour to long-chain alkanes, PE-water partitioning coefficients were compared to hexadecane-water partitioning coefficients estimated with the SPARC online calculator, COSMOtherm and a polyparameter linear free energy relationship based on the Abraham approach. The best correlation for all compounds tested was with COSMOtherm estimated hexadecane-water partitioning coefficients. PMID:20398988

Hale, Sarah E; Martin, Timothy J; Goss, Kai-Uwe; Arp, Hans Peter H; Werner, David

2010-07-01

283

Comparison of Lichen, Conifer Needles, Passive Air Sampling Devices, and Snowpack as Passive Sampling Media to Measure Semi-Volatile Organic Compounds in Remote Atmospheres  

PubMed Central

A wide range of semi-volatile organic compounds (SOCs), including pesticides and polycyclic aromatic hydrocarbons (PAHs), were measured in lichen, conifer needles, snowpack and XAD-based passive air sampling devices (PASDs) collected from 19 different U.S. national parks in order to compare the magnitude and mechanism of SOC accumulation in the different passive sampling media. Lichen accumulated the highest SOC concentrations, in part because of its long (and unknown) exposure period, while PASDs accumulated the lowest concentrations. However, only the PASD SOC concentrations can be used to calculate an average atmospheric gas-phase SOC concentration because the sampling rates are known and the media is uniform. Only the lichen and snowpack SOC accumulation profiles were statistically significantly correlated (r = 0.552, p-value <0.0001) because they both accumulate SOCs present in the atmospheric particle-phase. This suggests that needles and PASDs represent a different composition of the atmosphere than lichen and snowpack and that the interpretation of atmospheric SOC composition is dependent on the type of passive sampling media used. All four passive sampling media preferentially accumulated SOCs with relatively low air-water partition coefficients, while snowpack accumulated SOCs with higher log KOA values compared to the other media. Lichen accumulated more SOCs with log KOA > 10 relative to needles and showed a greater accumulation of particle-phase PAHs. PMID:22087860

SCHRLAU, JILL E.; GEISER, LINDA; HAGEMAN, KIMBERLY J.; LANDERS, DIXON H.

2011-01-01

284

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

285

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

286

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

287

Technical Assessment: WRAP 1 HVAC Passive Shutdown  

SciTech Connect

As the result of careful interpretation of DOE Order 6430.lA and other DOE Orders, the HVAC system for WRAP 1 has been greatly simplified. The HVAC system is now designed to safely shut down to Passive State if power fails for any reason. The fans cease functioning, allowing the Zone 1 and Zone 2 HVAC Confinement Systems to breathe with respect to atmospheric pressure changes. Simplifying the HVAC system avoided overdesign. Construction costs were reduced by eliminating unnecessary equipment. This report summarizes work that was done to define the criteria, physical concepts, and operational experiences that lead to the passive shutdown design for WRAP 1 confinement HVAC systems.

Ball, D.E.; Nash, C.R.; Stroup, J.L.

1993-08-12

288

Heterojunction solar cell with passivated emitter surface  

DOEpatents

A high-efficiency heterojunction solar cell wherein a thin emitter layer (preferably Ga.sub.0.52 In.sub.0.48 P) forms a heterojunction with a GaAs absorber layer. A passivating window layer of defined composition is disposed over the emitter layer. The conversion efficiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the window layer.

Olson, Jerry M. (Lakewood, CO); Kurtz, Sarah R. (Golden, CO)

1994-01-01

289

Passive and active control of jet turbulence  

NASA Technical Reports Server (NTRS)

Techniques for controlling the generation, growth, and interactions of large coherent structures in turbulent flows are discussed, reviewing the results of recent experimental investigations. The fundamental principles of active and passive coherent-structure manipulation are outlined; the effects of geometric modification are examined for the case of an elliptic jet; and particular attention is given to passive control via self-excitation, turbulence and noise suppression, control of pairing interaction via two-frequency excitation, and unsteady boundary-layer separation in wall jets. Diagrams and graphs of typical results are provided.

Fazle Hussain, A. K. M.; Husain, H. S.

1988-01-01

290

Heterojunction solar cell with passivated emitter surface  

DOEpatents

A high-efficiency heterojunction solar cell is described wherein a thin emitter layer (preferably Ga[sub 0.52]In[sub 0.48]P) forms a heterojunction with a GaAs absorber layer. A passivating window layer of defined composition is disposed over the emitter layer. The conversion efficiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the window layer. 1 fig.

Olson, J.M.; Kurtz, S.R.

1994-05-31

291

Dipole transducer enhancement from a passive resonator.  

PubMed

A passive resonator model for enhancing the low frequency performance of dipole transducers is presented using a spherical wave function model. It is shown that because the near field response of a dipole has the same on-axis low frequency dependence as an equivalent monopole, it can effectively excite a nearby monopole passive resonator and do this with enough strength to significantly modify the response of the system. Sample results are presented to demonstrate the performance enhancement and to illustrate the conversion of the dipole beam pattern to a nearly omni-directional beam pattern. PMID:25373949

Butler, John L; Butler, Alexander L; Curtis, Victoria

2014-11-01

292

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

293

The Construct Validity of Passive-Aggressive Personality Disorder  

PubMed Central

Although Passive Aggressive personality disorder (PAPD) plays an important role in many theories of personality pathology, it was consigned to the appendix of the fourth edition of the DSM. The scientific basis of this decision has been questioned, but several controversies persist regarding PAPD, including its structure, content validity, overlap with other PDs, and relations to validating variables such as personality traits, childhood experiences, and clinically relevant correlates. This study examined these facets of PAPD’s construct validity in a large clinical sample. Results suggest that the construct is unidimensional, internally consistent, and reasonably stable. Furthermore, PAPD appears systematically related to borderline and narcissistic personality disorders, sets of personality traits, and childhood experiences consistent with several theoretical formulations, dysfunction, substance abuse disorders, and history of hospitalizations. Overall, results support the construct validity of PAPD. PMID:19821648

Hopwood, Christopher J.; Morey, Leslie C.; Markowitz, John C.; Pinto, Anthony; Skodol, Andrew E.; Gunderson, John G.; Zanarini, Mary C.; Shea, M. Tracie; Yen, Shirley; McGlashan, Thomas H.; Ansell, Emily B.; Grilo, Carlos M.; Sanislow, Charles A.

2010-01-01

294

Advances in Inner Magnetosphere Passive and Active Wave Research  

NASA Technical Reports Server (NTRS)

This review identifies a number of the principal research advancements that have occurred over the last five years in the study of electromagnetic (EM) waves in the Earth's inner magnetosphere. The observations used in this study are from the plasma wave instruments and radio sounders on Cluster, IMAGE, Geotail, Wind, Polar, Interball, and others. The data from passive plasma wave instruments have led to a number of advances such as: determining the origin and importance of whistler mode waves in the plasmasphere, discovery of the source of kilometric continuum radiation, mapping AKR source regions with "pinpoint" accuracy, and correlating the AKR source location with dipole tilt angle. Active magnetospheric wave experiments have shown that long range ducted and direct echoes can be used to obtain the density distribution of electrons in the polar cap and along plasmaspheric field lines, providing key information on plasmaspheric filling rates and polar cap outflows.

Green, James L.; Fung, Shing F.

2004-01-01

295

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

296

Passive solar energy in Washington: results of the Washington passive solar design/build competition  

SciTech Connect

The Washington Passive Solar Design/Build Competition was held in an effort to encourage the design, construction, and marketing of moderately priced passive solar homes in Washington state. Four categories were established, including single and multi-family, new design and remodel. A number of commonly made thermal mistakes are discussed. Eight winning entries are presented along with four notable entries, for each of which is given an overview of the design, energy conservation measures, passive heating and cooling features, system operation, and thermal performance. (LEW)

Not Available

1982-03-01

297

Passive solar energy in Washington: Results of the Washington passive solar design/build/competition  

NASA Astrophysics Data System (ADS)

The Washington Passive Solar Design and Build Competition was held in an effort to encourage the design, construction, and marketing of moderately priced passive solar homes in Washington state. Four categories were established, including single and multi-family, new design and remodel. A number of commonly made thermal mistakes are discussed. Eight winning entries are presented along with four notable entries, for each of which is given as an overview of the design, energy conservation measures, passive heating and cooling features, system operation, and thermal performance.

1982-03-01

298

Passive solar energy design and materials  

Microsoft Academic Search

Passive solar approaches are examined, taking into account direct gain, the thermal storage wall, the solar greenhouse, the roof pond, and the convective loop. Various system components are considered. Window treatments are discussed along with thermal storage, freon-activated controls, hinged skylid shutters and nightwall clips, beadwalls, thermic diode solar panels, heat pipes, the Skytherm roof pond, the energy roof, Suncatcher

J. K. Paul

1979-01-01

299

Natural solar architecture: a passive primer  

Microsoft Academic Search

An active solar heating\\/cooling system requires fans, blowers, motors - high-cost technology. In passive systems, nature does the work, but many details must be considered - climatic factors, building site, dwelling size, etc. Ways to calculate all variables and costs are included. Thermodynamics and natural physical properties that can make solar heating and cooling practical and economical are explained; these

1978-01-01

300

Passive ranging using a single IR sensor  

SciTech Connect

As current defense system architectures change and downsize there is a need to accomplish more with each sensors capability. Desert Storm`s missile to aircraft and missile to missile engagements elevated the need to better cope with early and stealthy assessment of the adversaries location while providing minimal compromise to the operator. The use of stealth vehicles introduces a requirement to deploy sensors that silently assess tactical and theater issues [battle damage assessment (BDA) and theater missile defense (TMD)] without preengagement detection. IR sensor system development and high speed, parallel, distributed processing make practical the implementation of compact passive ranging packages aboard satellites and aircraft. Here, single IR Sensor Passive Ranging from an observer to a target embedded in the atmosphere exploits the effect of atmospheric attenuation of the signal. By judicious choice of wavebands the range and altitude to a target can be determined passively with a single observer. This result will be shown to be relatively insensitive to assumed atmospheric models or precise source spectral content. A detailed closed-form solution relating range (and altitude) to observed target intensities will be presented. Previous studies of this type have required either detailed knowledge of the source spectra or spectral resolution of individual rotational lines. The single sensor passive ranging methodology requires no such detailed information.

Jeffrey, W. [Inst. for Defense Analyses, Alexandria, VA (United States); Gobel, R.W. [Analytic Services, Inc., Arlington, VA (United States); Draper, J.S. [KTAADN, Inc., Newton, MA (United States)

1994-12-31

301

Passive damping in EDS maglev systems.  

SciTech Connect

There continues to be strong interest in the subjects of damping and drag forces associated with electrodynamic suspension (EDS) systems. While electromagnetic drag forces resist the forward motion of a vehicle and therefore consume energy, damping forces control, at least in part, the response of the vehicle to disturbances. Ideally, one would like to reduce the drag forces as much as possible while retaining adequate damping forces to insure dynamic stability and satisfactory ride quality. These two goals turn out to be difficult to achieve in practice. It is well known that maglev systems tend to be intrinsically under damped. Consequently it is often necessary in a practical system design to enhance the damping passively or actively. For reasons of cost and simplicity, it is desirable to rely as much as possible on passive damping mechanisms. In this paper, rough estimates are made of the passive damping and drag forces caused by various mechanisms in EDS systems. No attention will be given to active control systems or secondary suspension systems which are obvious ways to augment passive damping mechanisms if the latter prove to be inadequate.

Rote, D. M.

2002-05-03

302

Photodetectors with passive thermal radiation control  

DOEpatents

A new class of photodetectors which include means for passive shielding against undesired thermal radiation is disclosed. Such devices can substitute in applications currently requiring cooled optical sensors, such as IR detection and imaging. This description is included for purposes of searching, and is not intended to limit or otherwise influence the interpretation of the present invention.

Lin, Shawn-Yu (Albuquerque, NM); Fleming, James G. (Albuquerque, NM); Dodson, Brian W. (Albuquerque, NM)

2001-10-02

303

Inferring TCP Connection Characteristics Through Passive Measurements  

Microsoft Academic Search

We propose a passive measurement methodology to infer and keep track of the values of two important variables as- sociated with a TCP connection: the sender's congestion window (cwnd) and the connection round trip time (RTT). Together, these variables provide a valuable diagnostic of end-user-perceived network performance. Our methodology is validated via both simulation and concurrent active measurements, and is

Sharad Jaiswalt; Gianluca Iannaccone; Christophe DiotF; Donald F. Towsley

2004-01-01

304

Efficient Object Identification with Passive RFID Tags  

E-print Network

frequency identification systems with passive tags are power- ful tools for object identification. However such as asset tracking (e.g. libraries, ani- mals), automated inventory and stock-keeping, toll collecting, however. As examples, consider laundry services, warehouses, or the su- permarket checkout. We have

305

Treat mine water using passive methods  

SciTech Connect

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 an alternative to conventional treatment; others serve as an inexpensive pretreatment step than can decrease subsequent chemical requirements. Sulfide minerals present in rock disturbed during mining can oxidize to form an acidic metal-laden solution, commonly known as acid mine drainage (AMD). Alkalinity present in the rock may partially or completely neutralize AMD, but if either acidity or excessive metal contaminants remain, the water must be treated before it can be discharged legally. The principal regulated contaminant metals of coal mine drainage are iron and manganese. Metal mine drainage often contains more toxic metals, such as cadmium, nickel, copper and zinc. Chemical treatment of AMD is estimated to cost America's mining industry more than $1 million a day. Three principal passive technologies are used in the treatment of coal mine drainage: Aerobic wetlands, wetlands constructed with an organic substrate and anoxic limestone drains (ALDS). The selection of the technology or combination of technologies to be used depends on the quality of the water being treated.

Kleinmann, R.L.P.; Hedin, R.S. (U.S. Bureau of Mines, Pittsburgh, PA (United States). Environmental Technology Group)

1993-08-01

306

Mennonite Nursing Home passive solar demonstration  

SciTech Connect

A long-term nursing care facility and retirement center was designed for passive solar heating. The system comprises thermal mass, thermal insulation, Trombe walls, and direct gain clerestories. Included here is a topical report, analysis of building performance, owner's perspective, designer's perspective, and summary of information dissemination activities. (MHR)

Not Available

1984-03-01

307

NOTE / NOTE Transpiration-dependent passive silica  

E-print Network

NOTE / NOTE Transpiration-dependent passive silica accumulation in cucumber (Cucumis sativus) under transport Si, through transpiration, from soils to shoots, while others actively transport silica manipulated transpiration rates by changing humidity and air movements around pot-grown plants receiving

Kitajima, Kaoru

308

Passive Supporters of Terrorism and Phase Transitions  

E-print Network

We discuss some social contagion processes to describe the formation and spread of radical opinions. The dynamics of opinion spread involves local threshold processes as well as mean field effects. We calculate and observe phase transitions in the dynamical variables resulting in a rapidly increasing number of passive supporters. This strongly indicates that military solutions are inappropriate.

August, Friedrich; Delitzscher, Sascha; Hiller, Gerald; Krueger, Tyll

2010-01-01

309

Passive safety injection system using borated water  

DOEpatents

A passive safety injection system relies on differences in water density to induce natural circulatory flow patterns which help maintain prescribed concentrations of boric acid in borated water, and prevents boron from accumulating in the reactor vessel and possibly preventing heat transfer.

Conway, Lawrence E. (Allegheny, PA); Schulz, Terry L. (Westmoreland, PA)

1993-01-01

310

The Soil Moisture Active Passive (SMAP) Mission  

Microsoft Academic Search

The Soil Moisture Active Passive (SMAP) mission is one of the first Earth observation satellites being developed by NASA in response to the National Research Council's Decadal Survey. SMAP will make global measurements of the soil moisture present at the Earth's land surface and will distinguish frozen from thawed land surfaces. Direct observations of soil moisture and freeze\\/thaw state from

Dara Entekhabi; Eni G. Njoku; Peggy E. O'Neill; Kent H. Kellogg; Wade T. Crow; Wendy N. Edelstein; Jared K. Entin; Shawn D. Goodman; Thomas J. Jackson; Joel Johnson; John Kimball; Jeffrey R. Piepmeier; Randal D. Koster; Neil Martin; Kyle C. McDonald; Mahta Moghaddam; Susan Moran; Rolf Reichle; J. C. Shi; Michael W. Spencer; Samuel W. Thurman; Leung Tsang; Jakob Van Zyl

2010-01-01

311

Mechanical brake design for passive haptic device  

Microsoft Academic Search

This paper explores a new mechanical brake design to be used in order to limit the motion in low cost and high force passive haptic device design. The designed mechanical brake was inspired from the working principle of a coaster brake used in bicycles. The brake consists of conic surfaces actuated by a DC motor. A leaf spring is added

Serter Yilmaz; E. Ilhan Konukseven; Hakan Gurocak

2011-01-01

312

Passive suspensions incorporating inerters for railway vehicles  

Microsoft Academic Search

This paper investigates the possibility of improving the performance of railway vehicle suspensions by incorporating a newly developed mechanical device known as the inerter. A comparative study of several low-complexity passive suspension layouts is made. Improved performance for the lateral and vertical ride comfort, as well as lateral body movement when curving are demonstrated in comparison with the conventional suspension

Jason Zheng Jiang; Alejandra Z. Matamoros-Sanchez; Roger M. Goodall; Malcolm C. Smith

2012-01-01

313

Pitting corrosion of passivated zinc monocrystals  

SciTech Connect

The pitting and polarization characteristics of low-index surfaces of zinc monocrystals were studied in weakly alkaline (pH 9.2) solutions containing 0.1 M sodium chloride, using single-cycle potentiodynamic polarization tests and a scan rate of 0.5 mV/s. Tests were conducted in the presence and absence of a bicarbonate/carbonate buffer. Electrode surface orientations and crystallographic directions lying in these surfaces were determined using X-ray techniques. The surfaces were close to the (0001), (10{bar 1}0), and (11{bar 2}0) planes. Pit morphology was studied by scanning electron microscopy. Passivity was observed only in the buffered solution, and pitting of the passivated surface occurred near {minus}0.85 V{sub SCE}. The (0001) basal plane appeared to have a slightly better pitting resistance and a lower passive current density than the other orientations. Basal plane surfaces prepared by cleavage exhibited superior resistance to anodic dissolution in the unbuffered solution. Crystallographic pitting geometries observed on passivated crystals were attributed to the enhanced resistance of the (0001) plane to active dissolution. Events leading to pit initiation were reviewed in terms of localized changes in solution chemistry that resulted in a decreased pH and formation of soluble zinc chloride ion complexes (ZnCl{sub x}{sup [2{minus}x]+}).

Guo, R.; Weinberg, F.; Tromans, D. [Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Metals and Materials Engineering

1995-05-01

314

Submerged passively-safe power plant  

SciTech Connect

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.S.

1991-12-31

315

Passive Optical Terrain Relative Navigation Using APLNav  

Microsoft Academic Search

The NASA autonomous precision landing and hazard avoidance technology (ALHAT) program is developing an autonomous precision landing system capable of landing a spacecraft on the Moon. To achieve the desired 90 m (3sigma) landing accuracy terrain relative navigation (TRN) is necessary. The Johns Hopkins University Applied Physics Laboratory (APL) is developing a TRN system using passive optical terrain sensing for

Dewey Adams; Thomas B. Criss; Uday J. Shankar

2008-01-01

316

Passive Smoking in the Workplace: Selected Issues.  

ERIC Educational Resources Information Center

This report provides information about the health effects of passive smoking, the types of policies that are in force in the public and private sectors to control workplace smoking, and the costs and effects of those policies. The executive summary briefly highlights the three major areas of the report: (1) a review of the studies of health…

Congress of the U.S., Washington, DC. Office of Technology Assessment.

317

Improved obstacle detection using passive ranging  

NASA Astrophysics Data System (ADS)

Boeing-SVS (BSVS) has been developing a Passive Obstacle Detection System (PODS) under a Small Business Innovative Research (SBIR) contract with NAVAIR. This SBIR will provide image-processing algorithms for the detection of sub-pixel curvilinear features (i.e., power lines, poles, suspension cables, etc). These algorithms will be implemented in the SBIR to run on custom processor boards in real time. As part of the PODS development, BSVS has conducted a study to examine the feasibility of incorporating a passive ranging solution with the obstacle-detection algorithms. This passive ranging capability will not only provide discrimination between power lines and other naturally occurring linear features, but will also provide ranging information for other features in the image. Controlled Flight Into Terrain (CFIT) is a leading cause of both military and civil/commercial rotorcraft accidents. Ranging to other features could be invaluable in the detection of other obstacles within the flight path and therefore the prevention of CFIT accidents. The purpose of this paper is to review the PODS system (presented earlier) and discuss several methods for passive ranging and the performance expected from each of the methods.

Nixon, Matthew D.; Loveland, Rohan C.

2002-07-01

318

Neutralization of wastewater from nitrite passivation  

SciTech Connect

A method for neutralization of wastewater formed in nitrite passivation has been presented. The method consists of introducing urea into wastewater and acidifying it with sulphuric acid. Wastewater is neutralized with lime. After clarification, wastewater can be drained outside the plant.

Pawlowski, L.; Mientki, B.; Wasag, H.

1982-01-01

319

Passive millimeter-wave imaging polarimeter system  

Microsoft Academic Search

The Army has identified a need to rapidly identify, map, and classify natural and manmade features to aid situational awareness as well as mission and tactical planning. To address these needs, Digital Fusion and Trex Enterprises have designed a full Stokes, passive MMW imaging polarimeter that is capable of being deployed on an unmanned aerial vehicle. Results of a detailed

Christopher M. Persons; Christopher A. Martin; Michael W. Jones; Vladimir Kolinko; John A. Lovberg

2009-01-01

320

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

321

Passive wing pitch reversal in insect flight  

Microsoft Academic Search

between hovering with flapping wings and with a continuously rotating blade (e.g. helicopter flight). Although insects have the musculature to control the wing pitch during flight, we show here that aerodynamic and wing inertia forces are sucient to pitch the wing without the aid of the muscles. We study the passive nature of wing pitching in several observed wing kinematics,

ATTILA J. BERGOU; SHENG XU; Z. JANE WANG

2007-01-01

322

Passive wing pitch reversal in insect flight  

NASA Astrophysics Data System (ADS)

Wing pitch reversal, the rapid change of angle of attack near stroke transition, represents a difference between hovering with flapping wings and with a continuously rotating blade (e.g. helicopter flight). Although insects have the musculature to control the wing pitch during flight, we show here that aerodynamic and wing inertia forces are sufficient to pitch the wing without the aid of the muscles. We study the passive nature of wing pitching in several observed wing kinematics, including the wing motion of a tethered dragonfly, Libellula pulchella, hovering fruitfly, hovering hawkmoth and simplified dragonfly hovering kinematics. To determine whether the pitching is passive, we calculate rotational power about the torsion axis owing to aerodynamic and wing inertial forces. This is done using both direct numerical simulations and quasi-steady fluid force models. We find that, in all the cases studied here, the net rotational power is negative, signifying that the fluid force assists rather than resists the wing pitching. To further understand the generality of these results, we use the quasi-steady force model to analyse the effect of the components of the fluid forces at pitch reversal, and predict the conditions under which the wing pitch reversal is passive. These results suggest the pitching motion of the wings can be passive in insect flight.

Bergou, Attila J.; Xu, Sheng; Wang, Z. Jane

323

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

324

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

325

Sunspot Time Series: Passive and Active Intervals  

NASA Astrophysics Data System (ADS)

Solar activity slowly and irregularly decreases from the first spotless day (FSD) in the declining phase of the old sunspot cycle and systematically, but also in an irregular way, increases to the new cycle maximum after the last spotless day (LSD). The time interval between the first and the last spotless day can be called the passive interval (PI), while the time interval from the last spotless day to the first one after the new cycle maximum is the related active interval (AI). Minima of solar cycles are inside PIs, while maxima are inside AIs. In this article, we study the properties of passive and active intervals to determine the relation between them. We have found that some properties of PIs, and related AIs, differ significantly between two group of solar cycles; this has allowed us to classify Cycles 8 - 15 as passive cycles, and Cycles 17 - 23 as active ones. We conclude that the solar activity in the PI declining phase (a descending phase of the previous cycle) determines the strength of the approaching maximum in the case of active cycles, while the activity of the PI rising phase (a phase of the ongoing cycle early growth) determines the strength of passive cycles. This can have implications for solar dynamo models. Our approach indicates the important role of solar activity during the declining and the rising phases of the solar-cycle minimum.

Zi?ba, S.; Nieckarz, Z.

2014-07-01

326

Passive magnetic bearings for vehicular electromechanical batteries  

Microsoft Academic Search

This report describes the design of a passive magnetic bearing system to be used in electromechanical batteries (flywheel energy storage modules) suitable for vehicular use. One or two such EMB modules might, for example, be employed in a hybrid-electric automobile, providing efficient means for power peaking, i.e., for handling acceleration and regenerative braking power demands at high power levels. The

Post

1996-01-01

327

Stability guaranteed control: time domain passivity approach  

Microsoft Academic Search

A general framework for expanding the time-domain passivity control approach, to large classes of control systems is proposed. We show that large classes of control systems can be described from a network point of view. Based on the network presentation, the large classes of control systems are analyzed in a unified framework. In this unified network model, we define \\

Jee-Hwan Ryu; Dong-Soo Kwon; Blake Hannaford

2004-01-01

328

Introduction Passive acoustic telemetry has been  

E-print Network

26 Introduction Passive acoustic telemetry has been used for many years by fisheries and wildlife acoustic telemetry Robert A.Glazer and Gabriel A.Delgado Florida Fish and Wildlife Conservation Commission telemetry can be employed to design effective MFRs by elucidating im- portant life-history parameters

329

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

330

Passive machine augmented composite for multifunctional properties  

Microsoft Academic Search

This dissertation studies by experiment and numerical analysis an advanced composite material (Machine Augmented Composite or MAC) for enhancement of the passive damping while maintaining its stiffness. This MAC is composed of a pre-buckled wall structure placed within a viscoelastic matrix. The pre-buckled machine can contain viscous fluids for additional energy dissipation. For the experiments, the MAC was fabricated by

Jong Hyun Kim

2005-01-01

331

Design tools for passive solar applications  

SciTech Connect

Examples of passive solar design tools are given, categorized as either evaluation tools or guidance tools. A trend toward microcomputer-based tools is noted; however, these are usually developed for use by engineers rather than architects. The need for more instructive tools targeted specifically to designers is emphasized.

Balcomb, J.D.

1986-04-01

332

Passive remote sensing at microwave wavelengths  

Microsoft Academic Search

Passive remote sensing at microwave frequencies has applications which range from meteorology to oceanography and geology. The meteorological applications are the most fully developed and include measurements of the temperature profile of the atmosphere and of the atmospheric distribution of H2O and O3. Such measurements can he made from space or from the ground by utilizing the microwave resonances of

D. H. Staelin; H. M. Swarm; D. K. Reynolds

1969-01-01

333

Passive laminar flow control of crossflow vorticity  

Microsoft Academic Search

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.

Bruce J. Holmes

1990-01-01

334

The Development of Indirect Passives in English.  

ERIC Educational Resources Information Center

An analysis of indirect object passives in English and their development from Late Old English and Early Middle English suggests that their existence is related to the development of double object constructions. As long as the dative and accusative cases had not merged, neither pronominal nor nominal indirect objects required a preposition;…

Estival, Dominique

335

Passive photography from a creative perspective: \\  

Microsoft Academic Search

This paper aims to contribute with an understanding of meaningful experiences of photography, to support reflection upon the design of future camera devices. We have conducted a study of a passive camera device called Sensecam, which previously has been investigated as a memory aid, a combination of life-logging and memory tool and as a resource for digital narratives. We take

Sara Ljungblad

2009-01-01

336

Influence and Passivity in Social Media  

Microsoft Academic Search

The ever-increasing amount of information flowing through Social Media forces the members of these networks to compete for attention and influence by relying on other people to spread their message. A large study of information propagation within Twitter reveals that the majority of users act as passive information consumers and do not forward the content to the network. Therefore, in

Daniel M. Romero; Wojciech Galuba; Sitaram Asur; Bernardo A. Huberman

2010-01-01

337

Influence and passivity in social media  

Microsoft Academic Search

The ever-increasing amount of information flowing through Social Media forces the members of these networks to compete for attention and influence by relying on other people to spread their message. A large study of information propagation within Twitter reveals that the majority of users act as passive information consumers and do not forward the content to the network. Therefore, in

Daniel M. Romero; Wojciech Galuba; Sitaram Asur; Bernardo A. Huberman

2011-01-01

338

PCM Passive Cooling System Containing Active Subsystems  

NASA Technical Reports Server (NTRS)

A multistage system has been proposed for cooling a circulating fluid that is subject to intermittent intense heating. The system would be both flexible and redundant in that it could operate in a basic passive mode, either sequentially or simultaneously with operation of a first, active cooling subsystem, and either sequentially or simultaneously with a second cooling subsystem that could be active, passive, or a combination of both. This flexibility and redundancy, in combination with the passive nature of at least one of the modes of operation, would make the system more reliable, relative to a conventional cooling system. The system would include a tube-in-shell heat exchanger, within which the space between the tubes would be filled with a phase-change material (PCM). The circulating hot fluid would flow along the tubes in the heat exchanger. In the basic passive mode of operation, heat would be conducted from the hot fluid into the PCM, wherein the heat would be stored temporarily by virtue of the phase change.

Blanding, David E.; Bass, David I.

2005-01-01

339

Passive water and ion transport by cotransporters  

PubMed Central

The rabbit Na+-glucose (SGLT1) and the human Na+-Cl?-GABA (GAT1) cotransporters were expressed in Xenopus laevis oocytes, and passive Na+ and water transport were studied using electrical and optical techniques. Passive water permeabilities (Lp) of the cotransporters were determined from the changes in oocyte volume in response to osmotic gradients. The specific SGLT1 and GAT1 Lp values were obtained by measuring Lp in the presence and absence of blockers (phlorizin and SKF89976A). In the presence of the blockers, the Lp values of oocytes expressing SGLT1 and GAT1 were indistinguishable from the Lp of control oocytes. Passive Na+ transport (Na+ leak) was obtained from the blocker-sensitive Na+ currents in the absence of substrates (glucose and GABA). Passive Na+ and water transport through SGLT1 were blocked by phlorizin with the same sensitivity (inhibitory constant (Ki), 3-5 ?M). When Na+ was replaced with Li+, phlorizin also inhibited Li+ and water transport, but with a lower affinity (Ki, 100 ?M). When Na+ was replaced by choline, which is not transported, the SGLT1 Lp was indistinguishable from that in Na+ or Li+, but in this case water transport was less sensitive to phlorizin. The activation energies (Ea) for passive Na+ and water transport through SGLT1 were 21 and 5 kcal mol?1, respectively. The high Ea for Na+ transport is comparable to that of Na+-glucose cotransport and indicates that the process is dependent on conformational changes of the protein, while the low Ea for water transport is similar to that of water channels (aquaporins). GAT1 also behaved as an SKF89976A-sensitive water channel. We did not observe passive Na+ transport through GAT1. We conclude that passive water and Na+ transport through cotransporters depend on different mechanisms: Na+ transport occurs by a saturable uniport mechanism, and water permeation is through a low conductance water channel. In the case of SGLT1, we suggest that both the water channel and water cotransport could contribute to isotonic fluid transport across the intestinal brush border membrane. PMID:10373701

Loo, Donald D F; Hirayama, Bruce A; Meinild, Anne-Kristine; Chandy, Grischa; Zeuthen, Thomas; Wright, Ernest M

1999-01-01

340

Passive infrared remote sensing evidence for large, intermittent CO 2 emissions at Popocatépetl volcano, Mexico  

Microsoft Academic Search

Passive infrared (FTIR) and correlation spectrometer (COSPEC) measurements were conducted at Popocatépetl volcano during February 10 to 26, 1998 from sites 4 to 17 km distant from the summit. Volcano behavior was relatively quiet and SO2 flux averaged 1670±1420 t\\/day (51 measurements), relatively small for Popocatépetl. Concurrent HCl\\/SO2 and HF\\/SO2 ratios were 0.17±0.01 and 0.031±0.003, respectively, about the same as

Fraser Goff; Steven P Love; R. G Warren; Dale Counce; J Obenholzner; Claus Siebe; Stephen C Schmidt

2001-01-01

341

Surface passivation process of compound semiconductor material using UV photosulfidation  

DOEpatents

A method for passivating compound semiconductor surfaces by photolytically disrupting molecular sulfur vapor with ultraviolet radiation to form reactive sulfur which then reacts with and passivates the surface of compound semiconductors.

Ashby, Carol I. H. (Edgewood, NM)

1995-01-01

342

Renewable energy technologies for federal facilities. Passive solar design  

SciTech Connect

Renewable energy technologies for federal facilities using passive solar designs are presented. More than one million residences and 1, 700 commercial buildings across the U.S. now employ passive solar designs.

NONE

1996-05-01

343

Prediction techniques for passive systems' probability of failure  

E-print Network

This work fits into the wider framework of the on-going debate centered on Passive System reliability. Its aim is to provide insights into the design of a dependable method to evaluate the reliability of Passive Systems. ...

Cavalieri d'Oro, Edoardo

2007-01-01

344

Passive background correction method for spatially resolved detection  

DOEpatents

A method for passive background correction during spatially or angularly resolved detection of emission that is based on the simultaneous acquisition of both the passive background spectrum and the spectrum of the target of interest.

Schmitt, Randal L. (Tijeras, NM); Hargis, Jr., Philip J. (Albuquerque, NM)

2011-05-10

345

Passive compact molten salt reactor (PCMSR), modular thermal breeder reactor with totally passive safety system  

NASA Astrophysics Data System (ADS)

Design Study Passive Compact Molten Salt Reactor (PCMSR) with totally passive safety system has been performed. The term of Compact in the PCMSR name means that the reactor system is designed to have relatively small volume per unit power output by using modular and integral concept. In term of modular, the reactor system consists of three modules, i.e. reactor module, turbine module and fuel management module. The reactor module is an integral design that consists of reactor, primary and intermediate heat exchangers and passive post shutdown cooling system. The turbine module is an integral design of a multi heating, multi cooling, regenerative gas turbine. The fuel management module consists of all equipments related to fuel preparation, fuel reprocessing and radioactive handling. The preliminary calculations show that the PCMSR has negative temperature and void reactivity coefficient, passive shutdown characteristic related to fuel pump failure and possibility of using natural circulation for post shutdown cooling system.

Harto, Andang Widi

2012-06-01

346

(a) passive (b) interactive (c) passive-social Fig.1: Robot(s) as medium  

E-print Network

is applied to "robot Manzai," which is a Japanese comedy conversation usually performed by two people for merely presenting information to people, which we named a passive medium. This is the same as a news

Kanda, Takayuki

347

Passive standoff detection by differential FTIR radiometry: an overview of the CATSI project with recent results  

NASA Astrophysics Data System (ADS)

A selection of field trial results on the passive standoff detection by differential FTIR radiometry with the CATSI sensor is presented. This selection covers the seven-year development period (1998-2004) of the CATSI project. The results obtained with the CATSI instrument at two major field trials in Kansas (1998) and Nevada (2001) have shown the successful passive standoff detection of a number of chemical vapors at short and medium ranges of 100 m and 1.5 km, respectively. In particular, the detection method has been used at short range (100m) to map the column amounts of a methanol plume with an estimated uncertainty of the order of 15 - 30%. At medium range (1.5 km), the measurement technique has been successfully used to detect and identify low, medium and high concentrations of vapor mixtures of DMMP and SF6 but appears to have limited quantification capabilities in its original form. At long range, CATSI has successfully measured SF6 gas amounts at the 5.7-km range of DRDC Valcartier. The passive standoff detection of liquid contaminants on surfaces was tested with encouraging results. These results indicate that liquid contaminant agents deposited on high-reflectivity surfaces can be detected, identified and possibly quantified with passive sensors. For low-reflectivity surfaces, the presence of contaminants can usually be detected; however, their identification based on simple correlations with the absorption spectrum of the pure contaminant is not possible. In a field trial (Dugway Proving Ground, 2002) on the standoff detection of bio-aerosols, CATSI has detected large amounts of BG at ranges of up to 3 km. Recent field measurements for a standoff distance of 60 m suggests that the gas constituent ratios of complex mixtures can be properly retrieved from passive spectral measurements performed at 8 cm-1. These results from field experiments clearly show the relevance of the CATSI approach for the passive standoff detection by differential FTIR radiometry.

Theriault, Jean-Marc; Puckrin, Eldon; Lavoie, Hugo; Turcotte, Caroline S.; Bouffard, Francois; Dube, Denis

2004-12-01

348

Image-based dynamic visual feedback control via passivity approach  

Microsoft Academic Search

This paper deals with the image-based dynamic visual feedback control via the passivity approach which is investigated in the position-based one. We construct an energy function using the error in the image plane. The passivity of the visual feedback system is derived from the energy function. We show passivity of the image-based dynamic visual feedback system by combining the passivity

Hiroyuki Kawai; Toshiyuki Murao; Masayuki Fujita

2006-01-01

349

Passive acoustic tomography of the ocean using arrays of unknown shape  

NASA Astrophysics Data System (ADS)

It was recently established that ocean acoustic tomography based on an inversion of ray travel times can be implemented without use of any dedicated sound sources by cross-correlating the ambient noise recorded on two line arrays, the shapes of which are known. In contrast to active tomography, the amount of useful information from noise interferometry is proportional to the product of the numbers of receivers in the two arrays. In our study based on the 2D and 3D numerical experiments, we examine a hypothesis concerning the feasibility of simultaneous performance of a passive ray tomography and passive positioning of arrays through cross-correlation of ambient or shipping noise. The numerical experiments are conducted under conditions close to those of a field experiment on passive ocean tomography. It is demonstrated that, when using arrays of 20-40 hydrophones, the sound velocity profile and the array shape can be found from noise correlation to an accuracy adequate for oceanological and acoustic applications.

Goncharov, V. V.; Chepurin, Yu. A.; Godin, O. A.

2013-03-01

350

A 13-WEEK COMPARISON OF PASSIVE AND CONTINUOUS OZONE MONITORS AT FORESTED SITES IN NORTH-CENTRAL PENNSYLVANIA  

EPA Science Inventory

Ogawa passive 03 samplers were used in a 13-233k study (June 1-September 1, 1999) involving 11 forested and mountaintop sites in north-central Pennsylvania. Four of the sites were collocated with TECO model 49 O3 analyzers. A significant correlation (p...

351

A THIRTEEN-WEEK COMPARISON OF PASSIVE AND CONTINUOUS OZONE MONITORS AT FORESTED SITES IN NORTH-CENTRAL PENNSYLVANIA  

EPA Science Inventory

Ogawa passive 03 samplers were used in a 13-233k study (June 1-September 1, 1999) involving 11 forested and mountaintop sites in north-central Pennsylvania. Four of the sites were collocated with TECO model 49 O3 analyzers. A significant correlation (p...

352

Death Anxiety and Voluntary Passive Euthanasia: Influences of Proximity to Death and Experiences with Death in Important Other Persons.  

ERIC Educational Resources Information Center

Identified five sources of death anxiety. Significant relationships were observed between each source and experimental factors. The relationship between death anxiety and attitude toward voluntary passive euthanasia was explored, and a significant correlation was noted among elderly persons. Results were consistent with an idiographic orientation…

Devins, Gerald M.

1979-01-01

353

Passives in agrammatic sentence comprehension: A German study  

Microsoft Academic Search

Background: A large number of studies examining agrammatic comprehension of canonical and non?canonical sentences in Broca's aphasia have focused on passives and results have been interpreted in theoretical frameworks such as the trace deletion hypothesis (TDH: Grodzinsky, 1995a). However, there are a number of unresolved issues associated with passives. The linguistic analysis of passive structures in different languages has remained

Frank Burchert; Ria De Bleser

2004-01-01

354

The Passive in 3- and 4-Year-Olds  

ERIC Educational Resources Information Center

This paper argues that analyzing the patterns of individual subject performance in tests of comprehension of passives might give insight into how little children interpret passives: 3 and 4 year-olds seem to go through a range of passive interpretation, that varies from actual comprehension to total non-comprehension. The fact that some small…

de Barros Pereira Rubin, Maraci Coelho

2009-01-01

355

A Passive 2nd -Order Sigma-Delta Modulator for  

E-print Network

A Passive 2nd -Order Sigma-Delta Modulator for Low-Power Analog-to-Digital Conversion Angsuman Roy angsumanroy@gmail.com Abstract--A passive 2nd -order sigma-delta modulator based on a cascade of first of a conventional 1st -order passive sigma-delta modulator in order to improve the linearity of its transfer

Baker, R. Jacob

356

Passive Decomposition of Multiple Mechanical Systems under Coordination Requirements  

E-print Network

Passive Decomposition of Multiple Mechanical Systems under Coordination Requirements Dongjun Lee interacting with environments and/or humans under coordination requirements. The key innovation is the passive coordination and energetic passivity of the closed- loop system. It decomposes the system dynamics into shape

Lee, Dongjun

357

Control of a Mobile Robot with Passive Multiple Trailers  

Microsoft Academic Search

A mobile service robot can achieve reconfigurability by exploiting passive trailer systems. Reconfigurability provides significant practical advantages in order to deal with various service tasks. However, a motion control problem of a passive multiple trailer system is difficult, mainly because a kinematic model is highly nonlinear. It is shown how a robot with n passive trailers can be controlled in

Woojin Chung; Munsang Kim; Jae-bok Song

2004-01-01

358

Position control of manipulator with passive joints using dynamic coupling  

Microsoft Academic Search

A method of controlling the position of a manipulator composed of active and passive joints is described. The active joints have actuators and position sensors. The passive joints have holding brakes instead of actuators. While the brakes are released, the passive joints are indirectly controlled by the motion of the active joints using the coupling characteristics of manipulator dynamics. While

Hirohiko Arai; Susumu Tachi

1991-01-01

359

Energy-based Control of a Passive Haptic Device  

Microsoft Academic Search

We propose an energy-based control method of a passive haptic device equipped with electric brakes. Unstable behavior is observed in the passive haptic system due to time delay mainly arising from the slow update rate of the virtual environment. From the passive FME (force manipulability ellipsoid) analysis, a so-called direct force control method is proposed in this paper. Its gain

Changhyun Cho; Jae-bok Song; Munsang Kim; Chang-soon Hwang

2004-01-01

360

Synthesized passive feedback control of sensor-rich structures  

Microsoft Academic Search

The passivity property of dissipative mechanical structures has long been exploited in designing passive controllers that provide robust stability even in the presence of unmodeled dynamics of the system. For an input\\/output map of a flexible structure to be passive, collocation of the actuators and sensors is required and also the sensors should measure the velocity of the system. The

Padma Akella; John T. Wen

1997-01-01

361

Actuating a Simple 3D Passive Dynamic Walker Russ Tedrake  

E-print Network

-- The passive dynamic walker described in this paper is a robot with a minimal number of degrees of freedomActuating a Simple 3D Passive Dynamic Walker Russ Tedrake Computer Science and Artificial used to tune the characteristics of the robot's passive gait. Our sagittal plane model is closely

Tedrake, Russ

362

Active versus passive damping in large flexible structures  

NASA Technical Reports Server (NTRS)

Optimal passive and active damping control can be considered in the context of a general control/structure optimization problem. Using a mean square output response approach, it is shown that the weight sensitivity of the active and passive controllers can be used to determine an optimal mix of active and passive elements in a flexible structure.

Slater, Gary L.; Mclaren, Mark D.

1991-01-01

363

A comparison of serum harvesting methods and type of refractometer for determining total solids to estimate failure of passive transfer in calves.  

PubMed

Monitoring the passive transfer of immunoglobulins from colostrums particularly in noncentrifuged samples can be useful for calf health management programs. The results of total solids refractometry from centrifuge and noncentrifuge harvested sources of serum were highly correlated (R2 = 0.95). Results from a digital and a hand-held refractometer were highly correlated (R2 = 0.96). PMID:16808230

Wallace, Melissa M; Jarvie, Brenna D; Perkins, Nicole R; Leslie, Ken E

2006-06-01

364

A comparison of serum harvesting methods and type of refractometer for determining total solids to estimate failure of passive transfer in calves  

PubMed Central

Abstract Monitoring the passive transfer of immunoglobulins from colostrums particularly in noncentrifuged samples can be useful for calf health management programs. The results of total solids refractometry from centrifuge and noncentrifuge harvested sources of serum were highly correlated (R2 = 0.95). Results from a digital and a hand-held refractometer were highly correlated (R2 = 0.96). PMID:16808230

Wallace, Melissa M.; Jarvie, Brenna D.; Perkins, Nicole R.

2006-01-01

365

26 CFR 1.1398-1 - Treatment of passive activity losses and passive activity credits in individuals' title 11 cases.  

Code of Federal Regulations, 2010 CFR

...is the passive activity credit (as defined in section 469...Estate succeeds to losses and credits upon commencement of case. The bankruptcy estate (estate) succeeds...and unused passive activity credit (determined as of the...

2010-04-01

366

Comparison of the Cleaning Efficacy of Passive Sonic Activation and Passive Ultrasonic Activation After Hand Instrumentation in Molar Root Canals  

Microsoft Academic Search

The purpose of this study was to compare the cleaning efficacy of passive ultrasonic activation with that of passive sonic activation after hand instrumentation. Sixty curved molar canals were hand-instrumented to size 35 and divided into three groups. Group 1 received no further treat- ment. Group 2 received 3 rain of passive sonic activation. Group 3 received 3 rain of

Scott A. Jensen; Thomas L. Walker; Jeffrey W. Hutter; Brian K. Nicoll

367

Analysis and suppression of passive noise in surface microseismic data  

NASA Astrophysics Data System (ADS)

Surface microseismic surveys are gaining popularity in monitoring the hydraulic fracturing process. The effectiveness of these surveys, however, is strongly dependent on the signal-to-noise ratio of the acquired data. Cultural and industrial noise generated during hydraulic fracturing operations usually dominate the data, thereby decreasing the effectiveness of using these data in identifying and locating microseismic events. Hence, noise suppression is a critical step in surface microseismic monitoring. In this thesis, I focus on two important aspects in using surface-recorded microseismic seismic data: first, I take advantage of the unwanted surface noise to understand the characteristics of these noise and extract information about the propagation medium from the noise; second, I propose effective techniques to suppress the surface noise while preserving the waveforms that contain information about the source of microseisms. Automated event identification on passive seismic data using only a few receivers is challenging especially when the record lengths span over long durations of time. I introduce an automatic event identification algorithm that is designed specifically for detecting events in passive data acquired with a small number of receivers. I demonstrate that the conventional STA/LTA (Short-term Average/Long-term Average) algorithm is not sufficiently effective in event detection in the common case of low signal-to-noise ratio. With a cross-correlation based method as an extension of the STA/LTA algorithm, even low signal-to-noise events (that were not detectable with conventional STA/LTA) were revealed. Surface microseismic data contains surface-waves (generated primarily from hydraulic fracturing activities) and body-waves in the form of microseismic events. It is challenging to analyze the surface-waves on the recorded data directly because of the randomness of their source and their unknown source signatures. I use seismic interferometry to extract the surface-wave arrivals. Interferometry is a powerful tool to extract waves (including body-wave and surface-waves) that propagate from any receiver in the array (called a pseudo source) to the other receivers across the array. Since most of the noise sources in surface microseismic data lie on the surface, seismic interferometry yields pseudo source gathers dominated by surface-wave energy. The dispersive characteristics of these surface-waves are important properties that can be used to extract information necessary for suppressing these waves. I demonstrate the application of interferometry to surface passive data recorded during the hydraulic fracturing operation of a tight gas reservoir and extract the dispersion properties of surface-waves corresponding to a pseudo-shot gather. Comparison of the dispersion characteristics of the surface waves from the pseudo-shot gather with that of an active shot-gather shows interesting similarities and differences. The dispersion character (e.g. velocity change with frequency) of the fundamental mode was observed to have the same behavior for both the active and passive data. However, for the higher mode surface-waves, the dispersion properties are extracted at different frequency ranges. Conventional noise suppression techniques in passive data are mostly stacking-based that rely on enforcing the amplitude of the signal by stacking the waveforms at the receivers and are unable to preserve the waveforms at the individual receivers necessary for estimating the microseismic source location and source mechanism. Here, I introduce a technique based on the tau - p transform, that effectively identifies and separates microseismic events from surface-wave noise in the tau -p domain. This technique is superior to conventional stacking-based noise suppression techniques, because it preserves the waveforms at individual receivers. Application of this methodology to microseismic events with isotropic and double-couple source mechanism, show substantial improvement in the signal-to-noise ratio. Imaging of the processed field da

Forghani-Arani, Farnoush

368

Electrochemical emission and impedance spectroscopies of passive iron and carbon steel  

NASA Astrophysics Data System (ADS)

A high fidelity in situ technique for measuring electrochemical noise data on carbon steel in alkaline solutions, referred to as Electrochemical Emission Spectroscopy (EES), or Electrochemical Noise Measurement (ENM), has been developed in this thesis as a means of monitoring general corrosion and pitting corrosion on carbon steel in simulated DOE nuclear waste storage systems and to develop a better understanding of the corrosion processes of carbon steel in these environments. The data acquisition system is essential to the accuracy of voltage and current measurements and the validity of experimental data for further analysis. Time and frequency domain analyses display different characteristics for general corrosion and pitting corrosion. DOE raw noise data analysis shows that the penetration corrosion rate in liquid/sludge phases is in the order of 10-2--10-3 mm/year for the carbon steel-lined tanks in the DOE waste environments. In addition, good correlation has been observed between EES and traditional Linear Polarization Resistance (LPR) method in detecting the corrosion rates of carbon steel. The passive state on iron in EDTA (ethylene diammine tetra acetic acid, disodium salt, C10H14N2Na2O 8)-containing borate buffer solutions of pH ranging from 8.15 to 12.87 at ambient temperature has been explored using Electrochemical Impedance Spectroscopy (EIS), another powerful in situ electrochemical method for investigating steady-state electrochemical and corrosion systems. It has been found that frequency sweep range, perturbation voltage amplitude, solution pH, and film formation voltage are important factors to influence the impedance of passive iron. The steady-state passive films formed on iron have been shown to satisfy the conditions of linearity, causality, stability and finiteness, on the basis of the good agreement observed between the experimental impedance data and the Kramers-Kronig transforms calculated data over most of the frequency range employed. The Point Defect Model (PDM) has been tested as a valid means of accounting for the passivity of iron, and most of its predictions have been experimentally observed. An impedance model for passive iron based on the PDM has been developed to interpret the impedance of this metal in borate buffer solutions as a function of applied film formation voltage and solution pH. Nonlinear curve fitting to the experimental data derives kinetic parameters (transfer coefficients and standard rate constants) for the interfacial reactions occurring in the barrier oxide layer on passive iron. This thesis concludes that the dominant defects for passive iron must be oxygen vacancies, or cation (Fe2+ or possibly Fe3+) interstitials, or both, due to the electronic character of the passive film.

Liu, Jun

369

Transmission electron microscopy of undermined passive films on stainless steel  

SciTech Connect

A study has been made of the passive film remaining over pits on stainless steel using a high resolution transmission electron microscope. Type 305 stainless steel was passivated in a borate buffer solution and pitted in ferric chloride. Passive films formed at 0.2 V relative to a saturated calomel electrode were found to be amorphous. Films formed at higher potentials showed only broad diffraction rings. The passive film was found to cover a remnant lacy structure formed over pits passivated at 0.8 V. The metallic strands of the lace were roughly hemitubular in shape with the curved surface facing the center of the pit.

Isaacs, H.S.; Zhu, Y.; Sabatini, R.L. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science; Ryan, M.P. [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Materials

1999-06-01

370

Passively damped vibration welding system and method  

DOEpatents

A vibration welding system includes a controller, welding horn, an anvil, and a passive damping mechanism (PDM). The controller generates an input signal having a calibrated frequency. The horn vibrates in a desirable first direction at the calibrated frequency in response to the input signal to form a weld in a work piece. The PDM is positioned with respect to the system, and substantially damps or attenuates vibration in an undesirable second direction. A method includes connecting the PDM having calibrated properties and a natural frequency to an anvil of an ultrasonic welding system. Then, an input signal is generated using a weld controller. The method includes vibrating a welding horn in a desirable direction in response to the input signal, and passively damping vibration in an undesirable direction using the PDM.

Tan, Chin-An; Kang, Bongsu; Cai, Wayne W.; Wu, Tao

2013-04-02

371

Managing passive incontinence and incomplete evacuation.  

PubMed

Both passive faecal incontinence and evacuation difficulty are distressing and demoralising conditions, resulting in physical and psychological problems including social restrictions, loss of self-esteem, altered body image and loss of skin integrity. Conservative management and biofeedback therapy has been shown to help most patients with faecal incontinence and evacuation difficulty by creating a manageable situation that can significantly improve quality of life. However, some patients may not improve their symptoms and require alternative measures. This article reports an audit of the use of the Qufora mini irrigation system in 50 patients (48 female, 2 male) with passive faecal incontinence and/or evacuation difficulty who had failed to respond to conventional biofeedback. Seventy percent found the irrigation comfortable and 74% rated the system as good or acceptable. Two-thirds believed symptoms were improved and would wish to continue using the system. Prospective studies are needed to confirm which patients are most suitable and respond well to the irrigation. PMID:23752456

Collins, Brigitte; Norton, Christine

372

Relaxing passivity for human-robot interaction.  

SciTech Connect

Robots for high-force interaction with humans face particular challenges to achieve performance and coupled stability. Because available actuators are unable to provide sufficiently high force density and low impedance, controllers for such machines often attempt to mask the robots physical dynamics, though this threatens stability. Controlling for passivity, the state-of-the-art means of ensuring coupled stability, inherently limits performance to levels that are often unacceptable. A controller that imposes passivity is compared to a controller designed by a new method that uses limited knowledge of human dynamics to improve performance. Both controllers were implemented on a testbed, and coupled stability and performance were tested. Results show that the new controller can improve both stability and performance. The different structures of the controllers yield key differences in physical behavior, and guidelines are provided to assist in choosing the appropriate approach for specific applications.

Buerger, Stephen P. (Massachusetts Institute of Technology, Cambridge, MA.); Hogan, Neville

2007-03-01

373

Power wire signatures in passive infrared sensors  

NASA Astrophysics Data System (ADS)

Power cables present a persistent threat to helicopter pilots and have been responsible for a number of crashes in recent years. Active sensors are currently being developed to detect obstacles such as exposed power wires. However, the ability of passive sensors, such as forward-looking infrared (FLIR) systems currently employed on many rotary-wing aircraft, to detect such wires remains unclear. This study details observations, assumptions, and models that support the conclusion that wires are essentially reflective in nature, thus their signatures on passive thermal sensors depend principally on their surroundings. Because of this irregular nature and inconsistent appearance, predicting the performance of FLIRs in detecting wires is difficult and the utility of FLIRs as wire warning sensors is open to question.

Shea, James J.

1994-04-01

374

Passive appendages generate drift through symmetry breaking.  

PubMed

Plants and animals use plumes, barbs, tails, feathers, hairs and fins to aid locomotion. Many of these appendages are not actively controlled, instead they have to interact passively with the surrounding fluid to generate motion. Here, we use theory, experiments and numerical simulations to show that an object with a protrusion in a separated flow drifts sideways by exploiting a symmetry-breaking instability similar to the instability of an inverted pendulum. Our model explains why the straight position of an appendage in a fluid flow is unstable and how it stabilizes either to the left or right of the incoming flow direction. It is plausible that organisms with appendages in a separated flow use this newly discovered mechanism for locomotion; examples include the drift of plumed seeds without wind and the passive reorientation of motile animals. PMID:25354545

L?cis, U; Brosse, N; Ingremeau, F; Mazzino, A; Lundell, F; Kellay, H; Bagheri, S

2014-01-01

375

Integration of Passive Components for Spacecraft Avionics  

NASA Astrophysics Data System (ADS)

The NASA roadmap outlining future deep space missions to Europa and other outer planetary destinations calls for continued reductions in the mass and volume of the spacecraft avionics. Spacecraft power electronics, including the power switches and converters, remain difficult to miniaturize due to the need for large numbers of discrete passive components such as resistors, capacitors, inductors and transformers. As part of the System-on-a-chip program at the Center for Integrated Space Microsystems and at the University of Arkansas, we are working to develop integrated or embedded passive components geared specifically for use in power management and distribution (PMAD) in future avionics over the next five to ten years. This will not only enable a scaling down of the power subsystems, but will make possible new architectures such as "distributed" PMAD. Additional information is contained in the original extended abstract.

Brandon, E. J.; Wesseling, E.; White, V.; Lieneweg, U.; Mojarradi, M.; Ulrich, R.; Wasef, M.; Mantooth, A.

2001-01-01

376

Passive appendages generate drift through symmetry breaking  

NASA Astrophysics Data System (ADS)

Plants and animals use plumes, barbs, tails, feathers, hairs and fins to aid locomotion. Many of these appendages are not actively controlled, instead they have to interact passively with the surrounding fluid to generate motion. Here, we use theory, experiments and numerical simulations to show that an object with a protrusion in a separated flow drifts sideways by exploiting a symmetry-breaking instability similar to the instability of an inverted pendulum. Our model explains why the straight position of an appendage in a fluid flow is unstable and how it stabilizes either to the left or right of the incoming flow direction. It is plausible that organisms with appendages in a separated flow use this newly discovered mechanism for locomotion; examples include the drift of plumed seeds without wind and the passive reorientation of motile animals.

L?cis, U.; Brosse, N.; Ingremeau, F.; Mazzino, A.; Lundell, F.; Kellay, H.; Bagheri, S.

2014-10-01

377

Passive appendages generate drift through symmetry breaking  

PubMed Central

Plants and animals use plumes, barbs, tails, feathers, hairs and fins to aid locomotion. Many of these appendages are not actively controlled, instead they have to interact passively with the surrounding fluid to generate motion. Here, we use theory, experiments and numerical simulations to show that an object with a protrusion in a separated flow drifts sideways by exploiting a symmetry-breaking instability similar to the instability of an inverted pendulum. Our model explains why the straight position of an appendage in a fluid flow is unstable and how it stabilizes either to the left or right of the incoming flow direction. It is plausible that organisms with appendages in a separated flow use this newly discovered mechanism for locomotion; examples include the drift of plumed seeds without wind and the passive reorientation of motile animals. PMID:25354545

L?cis, U.; Brosse, N.; Ingremeau, F.; Mazzino, A.; Lundell, F.; Kellay, H.; Bagheri, S.

2014-01-01

378

Germanium detector passivated with hydrogenated amorphous germanium  

DOEpatents

Passivation of predominantly crystalline semiconductor devices (12) is provided for by a surface coating (21) of sputtered hydrogenated amorphous semiconductor material. Passivation of a radiation detector germanium diode, for example, is realized by sputtering a coating (21) of amorphous germanium onto the etched and quenched diode surface (11) in a low pressure atmosphere of hydrogen and argon. Unlike prior germanium diode semiconductor devices (12), which must be maintained in vacuum at cryogenic temperatures to avoid deterioration, a diode processed in the described manner may be stored in air at room temperature or otherwise exposed to a variety of environmental conditions. The coating (21) compensates for pre-existing undesirable surface states as well as protecting the semiconductor device (12) against future impregnation with impurities.

Hansen, William L. (Walnut Creek, CA); Haller, Eugene E. (Berkeley, CA)

1986-01-01

379

Passive load control for large wind turbines.  

SciTech Connect

Wind energy research activities at Sandia National Laboratories focus on developing large rotors that are lighter and more cost-effective than those designed with current technologies. Because gravity scales as the cube of the blade length, gravity loads become a constraining design factor for very large blades. Efforts to passively reduce turbulent loading has shown significant potential to reduce blade weight and capture more energy. Research in passive load reduction for wind turbines began at Sandia in the late 1990's and has moved from analytical studies to blade applications. This paper discusses the test results of two Sandia prototype research blades that incorporate load reduction techniques. The TX-100 is a 9-m long blade that induces bend-twist coupling with the use of off-axis carbon in the skin. The STAR blade is a 27-m long blade that induces bend-twist coupling by sweeping the blade in a geometric fashion.

Ashwill, Thomas D.

2010-05-01

380

Structural Damage Detection Using Virtual Passive Controllers  

NASA Technical Reports Server (NTRS)

This paper presents novel approaches for structural damage detection which uses the virtual passive controllers attached to structures, where passive controllers are energy dissipative devices and thus guarantee the closed-loop stability. The use of the identified parameters of various closed-loop systems can solve the problem that reliable identified parameters, such as natural frequencies of the open-loop system may not provide enough information for damage detection. Only a small number of sensors are required for the proposed approaches. The identified natural frequencies, which are generally much less sensitive to noise and more reliable than the identified natural frequencies, are used for damage detection. Two damage detection techniques are presented. One technique is based on the structures with direct output feedback controllers while the other technique uses the second-order dynamic feedback controllers. A least-squares technique, which is based on the sensitivity of natural frequencies to damage variables, is used for accurately identifying the damage variables.

Lew, Jiann-Shiun; Juang, Jer-Nan

2001-01-01

381

Variables Correlated with Violent Behavior in Young Children  

Microsoft Academic Search

A study was made at the Bronx Municipal Hospital Outpatient Clinic on correlates with violence in young children. A group of aggressive children were compared with a similar control group on non-assaultive children at the clinic. It was found that the non-assaultive group showed more passivity, day dreaming and sexually seductive behavior than the aggressive group, who were more prone

Robert Plutchik

1983-01-01

382

REAL TIME OPTICAL CORRELATION WHITE LIGHT FOURIER TWSFORMS  

E-print Network

REAL TIME OPTICAL CORRELATION USING WHITE LIGHT FOURIER TWSFORMS Final Report of the technical work this contract is an investigation of optical pre-detection processing of white light, passively illuminated that an instrument to analyze the spatial frequency content of a white light scene using pre-detection processing

Ribak, Erez

383

Passive ventilation for residential air quality control  

Microsoft Academic Search

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

Axley

1999-01-01

384

Delayed conception and active and passive smoking  

Microsoft Academic Search

Objective: To determine whether passive as well as active smoking by women or smoking by men is associated with delayed conception, after adjustment for confounding factors.Design: Population study of couples expecting a baby. Logistic regression was performed to identify factors associated with delayed conception.Setting: The Avon Health Authority area, United Kingdom.Patient(s): All couples expected to deliver between April 1991 and

Michael G. R Hull; Kate North; Hazel Taylor; Alexandra Farrow; W. Christopher L Ford

2000-01-01

385

Passive vibration absorber with dry friction  

Microsoft Academic Search

Summary  ?The properties of a passive vibration absorber with dry friction significantly differ from those of the classical linear\\u000a absorber. The exceptional phenomenon is the possibility of suppressing all excited modes. This effect is influenced to a small\\u000a extent by a special shape of the friction characteristic, but mainly by an appropriately adjusted threshold of the static\\u000a friction. The theoretical predictions

A. Hartung; H. Schmieg; P. Vielsack

2001-01-01

386

Passive modal damping with piezoelectric shunts  

SciTech Connect

The use of piezoelectric materials in conjunction with passive inductance-resistance-capacitance (RLC) circuits to dampen specific vibration modes is explored. The piezoelectric materials convert mechanical energy to electrical energy, which is then dissipated in the RLC circuit through joule heating. An impulse is applied to a simple cantilevered beam and by varying the inductance and resistance values, the natural oscillation frequency fcir the RLC circuit is tuned to dampen the first mode of vibration.

Granier, J. J. (John J.); Haundhausen, R. J. (R. Jason); Gaytan, G. E. (Gabriel E.)

2001-01-01

387

Increasing passive energy expenditure during clerical work  

Microsoft Academic Search

Sitting on a therapy ball or standing may be a passive means of increasing energy expenditure throughout the workday. The\\u000a purpose of this study was to determine the energy expenditure and liking of performing clerical work in various postures.\\u000a Subjects included 24 men and women employed in sedentary clerical occupations. Energy expenditure was measured while word\\u000a processing in three standardized

Erik A. Beers; James N. Roemmich; Leonard H. Epstein; Peter J. Horvath

2008-01-01

388

Passivation-free solid state battery  

Microsoft Academic Search

This invention pertains to passivation-free solid-state rechargeable batteries composed of LiâTiâOââ anode, a solid polymer electrolyte and a high voltage cathode. The solid polymer electrolyte comprises a polymer host, such as polyacrylonitrile, poly(vinyl chloride), poly(vinyl sulfone), and poly(vinylidene fluoride), plasticized by a solution of a Li salt in an organic solvent. The high voltage cathode includes LiMnâOâ, LiCoOâ, LiNiOâ and

K. M. Abraham; D. Peramunage

1998-01-01

389

High spatial resolution passive microwave sounding systems  

NASA Technical Reports Server (NTRS)

Two extensive series of flights aboard the ER-2 aircraft were conducted with the MIT 118 GHz imaging spectrometer together with a 53.6 GHz nadir channel and a TV camera record of the mission. Other microwave sensors, including a 183 GHz imaging spectrometer were flown simultaneously by other research groups. Work also continued on evaluating the impact of high-resolution passive microwave soundings upon numerical weather prediction models.

Staelin, D. H.; Rosenkranz, P. W.; Bonanni, P. G.; Gasiewski, A. W.

1986-01-01

390

Improved obstacle detection using passive ranging  

Microsoft Academic Search

Boeing-SVS (BSVS) has been developing a Passive Obstacle Detection System (PODS) under a Small Business Innovative Research (SBIR) contract with NAVAIR. This SBIR will provide image-processing algorithms for the detection of sub-pixel curvilinear features (i.e., power lines, poles, suspension cables, etc). These algorithms will be implemented in the SBIR to run on custom processor boards in real time. As part

Matthew D. Nixon; Rohan C. Loveland

2002-01-01

391

Passive Endwall Treatments for Enhancing Stability  

NASA Technical Reports Server (NTRS)

These lecture notes were presented at the von Karman Institutes lecture series on Advances in Axial Compressor Aerodynamics, May 2006. They provide a fairly extensive overview of what's been learned from numerous investigations of various passive casing endwall technologies that have been proposed for alleviating the stall limiting physics associated with the compressor endwall flow field. The lecture notes are organized to give an appreciation for the inventiveness and understanding of the earliest compressor technologists and to provide a coherent thread of understanding that has arisen out of the early investigations. As such the lecture notes begin with a historical overview of casing treatments from their infancy through the earliest proposed concepts involving blowing, suction and flow recirculation. A summary of lessons learned from these early investigations is provided at the end of this section. The lecture notes then provide a somewhat more in-depth overview of recent advancements in the development of passive casing treatments from the late 1990's through 2006, including advancements in understanding the flow mechanism of circumferential groove casing treatments, and the development of discrete tip injection and self-recirculating casing treatments. At the conclusion of the lecture notes a final summary of lessons learned throughout the history of the development of passive casing treatments is provided. Finally, a list of future needs is given. It is hoped that these lecture notes will be a useful reference for future research endeavors to improve our understanding of the fluid physics of passive casing treatments and how they act to enhance compressor stability, and that they will perhaps provide a springboard for future research activities in this area of interest

Hathaway, Michael D.

2007-01-01

392

Passive solar nursing home for Northern Kentucky  

SciTech Connect

This project is a 32-bed nursing home designed as an addition to an existing facility. Passive solar strategies included direct gain room windows and clerestories which admit light to phase change salt pouches in the ceilings of patient rooms. Corridors are skykighted; and the heating, ventilating, and conditioning system is comprised of water-source heat pumps and a 5000 gallon storage tank in conjunction with an air to air heat recovery wheel.

Taylor, J.G.; Ward, J.D.

1980-01-01

393

Passive magnetic bearings for vehicular electromechanical batteries  

SciTech Connect

This report describes the design of a passive magnetic bearing system to be used in electromechanical batteries (flywheel energy storage modules) suitable for vehicular use. One or two such EMB modules might, for example, be employed in a hybrid-electric automobile, providing efficient means for power peaking, i.e., for handling acceleration and regenerative braking power demands at high power levels. The bearing design described herein will be based on a ''dual-mode'' operating regime.

Post, R

1996-03-01

394

Passive solar manufactured buildings development and analyses  

NASA Astrophysics Data System (ADS)

Manufactured buildings which are cost effective residential and light commercial buildings are discussed. The solar energy research institute (SERI) and the Department of Energy (DOE) worked with building manufacturers design, develop, and build passive solar manufactured buildings. This development process lead to valuable information in design development and design options, cost analysis, and estimated and monitored thermal performance on all types of manufactured buildings. The scope and content are described.

Dekieffer, R.

1983-11-01

395

Passive target detection measurements at 220 GHz  

NASA Astrophysics Data System (ADS)

Passive target signature measurements were performed at 220 GHz and 95 GHz. Test results show target detection is possible even with very warm sky temperatures. A 220 GHz/94 GHz sensor was used to detect a metallic vehicle at a range of 300 meters during the summer. Using a raster scan format, scans were made above, through and below the target. The scene thus viewed included trees and grass. Measurements were also made of the overhead sky and calibrated hot and cold radiometer.

Foster, M. L.; Forsythe, R. E.; Welch, J. M.; Schuchardt, J. M.

1980-08-01

396

Parameter ranges for CW passive mode locking  

Microsoft Academic Search

CW passive mode locking of a homogeneously broadened laser is considered. In the coordinate plane, whose abscissa is proportional to the small-signal saturable absorber loading, and whose ordinate is proportional to the small-signal gain, the following regimes are laid out: 1) steady-state single-pulse mode-locking solutions; 2) stability against relaxation oscillations; 3) self-starting of mode locking. The assumption is made that

H. Haus

1976-01-01

397

Evaluation of Alternate Stainless Steel Surface Passivation Methods  

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, Elliot A.

2005-05-31

398

Passivation of irregular surfaces accessed by diffusion.  

PubMed

We investigate the process of progressive passivation of irregular surfaces accessed by diffusion. More precisely, we quantify through numerical simulations how the activity of the von Koch surface is gradually transferred from its initially active (or absorbing) regions to its less accessible regions. We show that in three dimensions, in sharp contrast with the two-dimensional case, the size of the successive active zones steadily decreases during the passivation process, even though a large quantity of alive surface remains available. As a consequence, in three dimensions, the evolution of the efficiency of a surface accessed by diffusion (i.e., by a Laplacian field) can exhibit long-tail behaviors that, unlike in two dimensions, strongly depend on its specific geometry. This fact has important implications for the design of heterogeneous catalysts under deactivation conditions, for the performance of heat exchangers subjected to passivation by "fouling," and for changes in the behavior of the digestive system, where the activity of the absorbing intestinal membrane can be substantially affected by inflammatory disorders. PMID:18509056

Filoche, M; Grebenkov, D S; Andrade, J S; Sapoval, B

2008-06-01

399

Eighth national passive solar conference. Final report  

SciTech Connect

The Eighth National Passive Solar Conference was held near Santa Fe, New Mexico at the Glorieta Conference Center on September 5 to 11, 1983. Nearly 900 people from all across the nation and the world attended the conference. Close to 200 technical papers were presented, 50 solar product exhibits were available; 34 poster sessions were presented; 16 solar workshops were conducted; 10 renowned solar individuals participated in rendezvous sessions; 7 major addresses were delivered; 5 solar home tours were conducted; 2 emerging architecture sessions were held which included 21 separate presentations; and commercial product presentations were given for the first time ever at a national passive solar conference. Peter van Dresser of Santa Fe received the prestigious Passive Solar Pioneer Award, posthumously, from the American Solar Energy Society and Benjamin T. Buck Rogers of Embudo received the prestigious Peter van Dresser Award from the New Mexico Solar Energy Association. This report reviews conference organization, attendance, finances, conference evaluation form results, and includes press coverage samples, selected conference photos courtesy of Marshall Tyler, and a summary with recommendations for future conferences. The Appendices included conference press releases and a report by the New Mexico Solar Industry Development Corporation on exhibits management.

Owen, A.; Zee, R.

1983-12-01

400

Management requirements of a passive access network  

NASA Astrophysics Data System (ADS)

The Broadband Access Facility (BAF) is an affordable method of providing broadband services for the local loop. It is based on the transport of ATM Cells over a shared fiber passive optical network (PON) with a passive optical tree and branch topology. The PON supports 622 Mbits/s over 32 network terminations (BAF-NTs) using a passive optical splitter/combiner. The management architecture of the BAF is based on the CCITT Telecommunications Management Network (TMN) recommendations. The management and control requirements have been analyzed using the OSI decomposition into five functional areas: configuration management (controls the `ranging' procedure which compensates for different distances between the BAF-NTs and the BAF-LT); performance management (manages the allocation of bandwidth between the subscribers to provide statistical gain and monitors network parameters to measure how well the BAF MAC protocol provides the agreed service); fault management (set of functions which enables the detection, isolation, correction of abnormal operation); security management (supports encryption cells which is necessary due to their broadcasting to all the BAF-NTs); and finally, accounting functions.

Sanchez, Jorge E.; Glick, Steve; Sham, Queenie; Sara, Lini; Cuthbert, Laurie; Venieris, Iakovos S.; Mourelatou, K.

1993-11-01

401

Stable surface passivation process for compound semiconductors  

DOEpatents

A passivation process for a previously sulfided, selenided or tellurated III-V compound semiconductor surface. The concentration of undesired mid-gap surface states on a compound semiconductor surface is reduced by the formation of a near-monolayer of metal-(sulfur and/or selenium and/or tellurium)-semiconductor that is effective for long term passivation of the underlying semiconductor surface. Starting with the III-V compound semiconductor surface, any oxidation present thereon is substantially removed and the surface is then treated with sulfur, selenium or tellurium to form a near-monolayer of chalcogen-semiconductor of the surface in an oxygen-free atmosphere. This chalcogenated surface is then contacted with a solution of a metal that will form a low solubility chalcogenide to form a near-monolayer of metal-chalcogen-semiconductor. The resulting passivating layer provides long term protection for the underlying surface at or above the level achieved by a freshly chalcogenated compound semiconductor surface in an oxygen free atmosphere.

Ashby, Carol I. H. (Edgewood, NM)

2001-01-01

402

Jitter suppression experiment passive damping design cycle  

NASA Astrophysics Data System (ADS)

The University of Dayton Research Institute is teamed with McDonnell Douglas Aerospace to develop and fly a NASA IN-STEP experiment entitled Jitter Suppression Experiment (JSX). The JSX will demonstrate a combined active/passive vibration control system on an actual full scale space structure. This paper presents the details of the design of the passive control system to be applied to six graphite/epoxy support tubes for a gimballed telescope assembly (GTA) and the results of concept development laboratory tests. The most promising damping concepts for tubes such as the GTA truss tubes were constrained layer dampers and tuned dampers. The advantages and disadvantages of each of these damping concepts and the reasons for choosing a constrained layer concept are discussed. To verify the effectiveness of the passive damping design and to determine the constrained layer damping system effectiveness for axial modes, a finite element analysis of a single truss tube with the proposed constraining layer design was performed. A laboratory simulation was designed, developed, and evaluated to verify the analysis.

Drake, Michael L.; Frank, Geoffrey J.; Olson, Steven E.

1994-05-01

403

Frequency-sum passive cavitation imaging.  

PubMed

Passive cavitation imaging (PCI) is a method for spatially mapping acoustic emissions caused by microbubble activity, including subharmonic and ultraharmonic emissions that denote stable cavitation. The point spread function (PSF) of passive cavitation images is diffraction limited. When typical clinical diagnostic linear arrays are used for PCI, the diffraction limit results in high azimuthal resolution but low axial resolution. Abadi et al. (2013)recently demonstrated a method called frequency-sum beamforming, which employs second-order or higher products of the acoustic emissions to manufacture higher frequencies, thereby reducing the size of the PSF. We applied this approach to cavitation emissions recorded from albumin-shelled bubbles insonified by 2 MHz ultrasound. Cavitation emissions were recorded on a 5 MHz, 128 element linear array using a Vantage scanner (Verasonics Inc.). Quadratic and fourth-order frequency-sum beamforming was applied to both harmonic and ultraharmonic cavitation emissions. Corresponding simulations were also performed to illustrate frequency-sum passive cavitation imaging of multiple bubbles. In comparison to delay-and-sum PCI, apparent areas of cavitation activity decreased when products of the emissions were used to perform frequency-sum beamforming. However, frequency-sum beamforming also produced artifacts, including the appearance of spurious emission sources. PMID:25235673

Haworth, Kevin J; Radhakrishnan, Kirthi; Mast, T Douglas

2014-04-01

404

Passive dynamic controllers for nonlinear mechanical systems  

NASA Technical Reports Server (NTRS)

A methodology for model-independant controller design for controlling large angular motion of multi-body dynamic systems is outlined. The controlled system may consist of rigid and flexible components that undergo large rigid body motion and small elastic deformations. Control forces/torques are applied to drive the system and at the same time suppress the vibration due to flexibility of the components. The proposed controller consists of passive second-order systems which may be designed with little knowledge of the system parameter, even if the controlled system is nonlinear. Under rather general assumptions, the passive design assures that the closed loop system has guaranteed stability properties. Unlike positive real controller design, stabilization can be accomplished without direct velocity feedback. In addition, the second-order passive design allows dynamic feedback controllers with considerable freedom to tune for desired system response, and to avoid actuator saturation. After developing the basic mathematical formulation of the design methodology, simulation results are presented to illustrate the proposed approach to a flexible six-degree-of-freedom manipulator.

Juang, Jer-Nan; Wu, Shih-Chin; Phan, Minh; Longman, Richard W.

1991-01-01

405

Isoform diversity of giant proteins in relation to passive and active contractile properties of rabbit skeletal muscles.  

PubMed

The active and passive contractile performance of skeletal muscle fibers largely depends on the myosin heavy chain (MHC) isoform and the stiffness of the titin spring, respectively. Open questions concern the relationship between titin-based stiffness and active contractile parameters, and titin's importance for total passive muscle stiffness. Here, a large set of adult rabbit muscles (n = 37) was studied for titin size diversity, passive mechanical properties, and possible correlations with the fiber/MHC composition. Titin isoform analyses showed sizes between approximately 3300 and 3700 kD; 31 muscles contained a single isoform, six muscles coexpressed two isoforms, including the psoas, where individual fibers expressed similar isoform ratios of 30:70 (3.4:3.3 MD). Gel electrophoresis and Western blotting of two other giant muscle proteins, nebulin and obscurin, demonstrated muscle type-dependent size differences of < or =70 kD. Single fiber and single myofibril mechanics performed on a subset of muscles showed inverse relationships between titin size and titin-borne tension. Force measurements on muscle strips suggested that titin-based stiffness is not correlated with total passive stiffness, which is largely determined also by extramyofibrillar structures, particularly collagen. Some muscles have low titin-based stiffness but high total passive stiffness, whereas the opposite is true for other muscles. Plots of titin size versus percentage of fiber type or MHC isoform (I-IIB-IIA-IID) determined by myofibrillar ATPase staining and gel electrophoresis revealed modest correlations with the type I fiber and MHC-I proportions. No relationships were found with the proportions of the different type II fiber/MHC-II subtypes. Titin-based stiffness decreased with the slow fiber/MHC percentage, whereas neither extramyofibrillar nor total passive stiffness depended on the fiber/MHC composition. In conclusion, a low correlation exists between the active and passive mechanical properties of skeletal muscle fibers. Slow muscles usually express long titin(s), predominantly fast muscles can express either short or long titin(s), giving rise to low titin-based stiffness in slow muscles and highly variable stiffness in fast muscles. Titin contributes substantially to total passive stiffness, but this contribution varies greatly among muscles. PMID:16230467

Prado, Lucas G; Makarenko, Irina; Andresen, Christian; Krüger, Martina; Opitz, Christiane A; Linke, Wolfgang A

2005-11-01

406

Pulse and noise properties of a two section passively mode-locked quantum dot laser under long delay feedback  

NASA Astrophysics Data System (ADS)

We present a numerical analysis that focuses on the temporal pulse properties of a monolithic two-section passively mode locked quantum dot laser subject to optical feedback from a very long external cavity. Pulse duration, shape and intensity noise are studied for the first time to our knowledge versus feedback delay and strength for the case of a passively mode locked semiconductor laser. These temporal characteristics are correlated to the previously observed dependence of repetition rate and timing jitter on cavity parameters in order to highlight the dynamics and complete the corresponding theoretical explanations.

Simos, Christos; Simos, Hercules; Mesaritakis, Charis; Kapsalis, Alexandros; Syvridis, Dimitris

2014-02-01

407

Consequences of passive smoking in home environment.  

PubMed

Passive smoking means cigarette smoke inhaling by people other than smokers. Passive smoker inhales tobacco smoke coming not only from side-stream, but also smoke exhaled by the smoker. Long-term tobacco smoke inhaling increases the risk of appearance of smoke related diseases (for example COPD, heart diseases), including the most dangerous types of cancer, which only few smokers realize. The aim of this study was to check whether tobacco smoke inhaling in home environment from childhood to adulthood has an influence on respiratory system of adults. The study included adults. In the study two types of participants division were used. Among 1481 persons two groups were separated. Group 1 contains people, who have never lived in home environment with active smokers, altogether 465 persons. Group 2 contains people who from birth have been exposed to cigarette smoke inhaling (altogether 1016 persons). With help of the author's questionnaire the information concerning demographic features and smoking habit were gathered. The patients underwent doctor's examination. They had a spirometric test and a chest radiogram. Statistically significant differences appear among persons with higher education who belong to two different groups. The number of children who have lived in smoke free rooms during childhood and adolescence and finished studies is bigger than the number of active smokers' children (p<0.001). Over 90% of never smokers have inhaled cigarette smoke since childhood in home environment. Chronic obstructive pulmonary disease has been diagnosed at 47.5% of active smokers, 48.3% of ex-smokers and up to 44.7% of passive smokers. Cigarette smoking and smoke inhaling for more than twenty years has a significant influence on the appearance of COPD. No statistically significant differences were noted among the three groups of participants. (p>0.05). Cigarette smoke inhaling at childhood and adolescence should be taken seriously because it causes development of chronic diseases like COPD. GOLD 2006 standards convince that at every stage of COPD development the effects of this disease may be partly reversed if one stops smoking cigarettes. That is why a child should not be exposed to cigarette smoke at any stage of its life. Permanent inhalation of tobacco smoke since early childhood in home environment influences equal occurrence of COPD at passive, ex- and active smokers. Reduction of tobacco consumption, better care concerning passive smokers, increasing consciousness of parents smoking in home environment may protect their children from serious health consequences in the future. PMID:18409274

Ka?ucka, Sylwia

2007-01-01

408

Electrochemical characterization of anode passivation mechanisms in copper electrorefining  

NASA Astrophysics Data System (ADS)

Anode passivation can decrease productivity and quality while increasing costs in modern copper electrorefineries. This investigation utilized electrochemical techniques to characterize the passivation behavior of anode samples from ten different operating companies. It is believed that this collection of anodes is the most diverse set ever to be assembled to study the effect of anode composition on passivation. Chronopotentiometry was the main electrochemical technique, employing a current density of 3820 A m-2. From statistical analysis of the passivation characteristics, increasing selenium, tellurium, silver, lead and nickel were shown to accelerate passivation. Arsenic was the only anode impurity that inhibited passivation. Oxygen was shown to accelerate passivation when increased from 500 to 1500 ppm, but further increases did not adversely affect passivation. Nine electrolyte variables were also examined. Increasing the copper, sulfuric acid or sulfate concentration of the electrolyte accelerated passivation. Arsenic in the electrolyte had no effect on passivation. Chloride and optimal concentrations of thiourea and glue delayed passivation. Linear sweep voltammetry, cyclic voltammetry, and impedance spectroscopy provided complementary information. Analysis of the electrochemical results led to the development of a unified passivation mechanism. Anode passivation results from the formation of inhibiting films. Careful examination of the potential details, especially those found in the oscillations just prior to passivation, demonstrated the importance of slimes, copper sulfate and copper oxide. Slimes confine dissolution to their pores and inhibit diffusion. This can lead to copper sulfate precipitation, which blocks more of the surface area. Copper oxide forms because of the resulting increase in potential at the interface between the copper sulfate and anode. Ultimate passivation occurs when the anode potential is high enough to stabilize the oxide film in the bulk electrolyte. The effect of anode impurities or electrolyte concentrations can be related to the formation of one of these films. Reactions occurring after passivation have also been examined. Post-passivation reactions are believed to include silver dissolution, transformation of lead sulfate to lead oxide, and oxygen evolution. Following the sharp potential increase caused by the passivation, silver that has accumulated on the anode surface will dissolve into the electrolyte at a potential between 1.0 and 1.3 V. After the silver has dissolved, the potential increases again at which point the oxidation of lead sulfate to lead oxide occurs. The formation of lead oxide provides a surface with a lower oxygen evolution overpotential. The presence of kupferglimmer also results in a stable lower oxygen evolution potential occurring at approximately 2.0 V.

Moats, Michael Scott

409

Early production of the passive in two Eastern Bantu languages  

PubMed Central

The passive construction is acquired relatively late by children learning to speak many languages, with verbal passives not fully acquired until age 6 in English. In other languages it appears earlier, around age 3 or before. Use of passive construction in young children was examined in two Eastern Bantu languages spoken in Kenya (Kiswahili and Kigiriama), both with frequent use of passive. The passive was used productively very early (2;1) in these languages, regardless of the method used to measure productivity. In addition, non-actional passives, particularly rare in English and some other European languages, were seen at these early ages. The proportion of verbs that were passive varied between individuals, both in children’s speech and in the input to children. Pragmatic and grammatical features of the passive in some languages have previously been suggested to drive early passive acquisition, but these features are not found consistently in the two languages studied here. Findings suggest that the relatively high frequency of input found in these languages is the most plausible reason for early productive use of the passive. PMID:23750059

Alcock, Katherine J; Rimba, Kenneth; Newton, Charles RJC

2013-01-01

410

Cavity length dependence of mode beating in passively Q-switched Nd-solid state lasers  

NASA Astrophysics Data System (ADS)

The temporal intensity profile of pulse(s) from passively Q-switched and passively Q-switched mode locked (QSML) solid-state lasers is known to be dependent on cavity length. In this work, the pulse width, modulation depth, and beat frequencies of a Nd:Cr:GSGG laser using a Cr+4:YAG passive Q-switch are investigated as function cavity length. Measured temporal widths are linearly correlated with cavity length but generally 3-5 ns larger than theoretical predictions. Some cavity lengths exhibit pulse profiles with no modulation while other lengths exhibit complete amplitude modulation. The observed beat frequencies at certain cavity lengths cannot be accounted for with passively QSML models in which the pulse train repetition rate is ?RT-1, ?RT= round-trip time. They can be explained, however, by including coupled cavity mode-locking effects. A theoretical model developed for a two section coupled cavity semiconductor laser is adapted to a solid-state laser to interpret measured beat frequencies. We also numerically evaluate the temporal criterion required to achieve temporally smooth Q-switched pulses, versus cavity length and pump rate. We show that in flash lamp pumped systems, the difference in buildup time between longitudinal modes is largely dependent on the pump rate. In applications where short pulse delay is important, the pumping rate may limit the ability to achieve temporally smooth pulses in passively Q-switched lasers. Simulations support trends in experimental data. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Zameroski, Nathan D.; Wanke, Michael; Bossert, David

2013-03-01

411

Cosmic microwave background bispectrum of tensor passive modes induced from primordial magnetic fields  

E-print Network

If the seed magnetic fields exist in the early Universe, tensor components of their anisotropic stresses are not compensated prior to neutrino decoupling and the tensor metric perturbations generated from them survive passively. Consequently, due to the decay of these metric perturbations after recombination, so-called, integrated Sachs-Wolfe effect, the large-scale fluctuations of the cosmic microwave background (CMB) radiation are significantly boosted. This kind of the CMB anisotropy is called "tensor passive mode". Because these fluctuations deviate largely from the Gaussian statistics due to the quadratic dependence on the strength of the Gaussian magnetic field, not only the power spectrum but also the higher-order correlations have reasonable signals. With these motives, we compute the CMB bispectrum induced by this mode. When the magnetic spectrum obeys a nearly scale-invariant shape, we obtain an estimation of a typical value of the normalized reduced bispectrum as $\\ell_1(\\ell_1 + 1)\\ell_3(\\ell_3+1)...

Shiraishi, Maresuke; Yokoyama, Shuichiro; Ichiki, Kiyotomo; Takahashi, Keitaro

2011-01-01

412

Molecular arrangement investigation of copper phthalocyanine grown on hydrogen passivated Si(1 1 1) surfaces  

NASA Astrophysics Data System (ADS)

Chemical, electronic and structural properties of ultra thin films of copper phthalocyanine (CuPc) grown on hydrogen passivated silicon (1 1 1) surfaces were investigated in situ by X-ray photoelectron spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS), X-ray photoelectron diffraction (XPD) and electron diffraction (LEED). The early stages of copper phthalocyanine adsorption (1-2) were characterized by the saturation of surface defects and by a flat lying disposition on the surface. Upon further CuPc coverage, the passivation of Si surfaces resulted in the molecule taking a standing position in films. The molecular packing deduced from these studies appears very close to the one in the bulk ? phase of CuPc. The work function of the films was found to be decreasing during the growth and was correlated with the molecular orientation.

Arbi, I.; Ben Hamada, B.; Souissi, A.; Menzli, S.; Ben Azzouz, C.; Laribi, A.; Akremi, A.; Chefi, C.

2014-06-01

413

Mixing of a passive scalar in isotropic and sheared homogeneous turbulence  

NASA Technical Reports Server (NTRS)

In order to calculate the velocity and scalar fields, the three dimensional, time-dependent equations of motion and the diffusion equation were solved numerically. The following cases were treated: isotropic, homogeneous turbulence with decay of a passive scalar; and homogeneous turbulent shear flow with a passive scalar whose mean varies linearly in the spanwise direction. The solutions were obtained at relatively low Reynolds numbers so that all of the turbulent scales could be resolved without modeling. Turbulent statistics such as integral length scales, Taylor microscales, Kolmogorov length scale, one- and two-point correlations of velocity-velocity and velocity-scalar, turbulent Prandtl/Schmidt number, r.m.s. values of velocities, the scalar quantity and pressure, skewness, decay rates, and decay exponents were calculated. The results are compared with the available expermental results, and good agreement is obtained.

Shirani, E.; Ferziger, J. H.; Reynolds, W. C.

1981-01-01

414

The Relationship of Tropical Cyclone Convective Intensity to Passive Microwave Observations  

NASA Technical Reports Server (NTRS)

During the 1998 and 2001 hurricane seasons, the Advanced Microwave Precipitation Radiometer (AMPR) was flown aboard the National Aeronautics and Space Administration (NASA) ER-2 high altitude aircraft as part of the Third Convection And Moisture EXperiment (CAMEX-3) and the Fourth Convection And Moisture Experiment (CAMEX-4). Several hurricanes and tropical storms were sampled during these experiments. The passive microwave observations of these tropical cyclones collected at frequencies of 10.7, 19.35, 37.1, and 85.5 GHz will be presented to explain differences in precipitation features of the hurricanes. In particular, the relationship of the passive microwave signatures of precipitation-sized ice to vertical updraft strength will be examined as a possible indicator of future convective intensity. Correlated aircraft radar, lightning, visible and infrared information will also be examined to provide further insight.

Hood, Robbie E.; Guillory, Anthony; LaFontaine, Frank J.; Cecil, Dan; Heymsfield, Gerald; Arnold, James E. (Technical Monitor)

2002-01-01

415

Investigation of the Noncondensable Effect and the Operational Modes of the Passive Condenser System  

SciTech Connect

An experimental study is performed to investigate the effect of noncondensable gas in a passive condenser system. A vertical condenser tube is submerged in a water pool where the heat transferred from the condenser tube is removed through boiling. Data are obtained for three operational modes of the passive condenser. Degradation of the condensation with noncondensable gas is investigated. The condensation heat transfer rate is enhanced by increasing the inlet steam flow rate and the system pressure. For the condenser submerged in a saturated water pool, strong primary pressure dependency is observed. A boundary layer-based condensation model and a simple condensation model with the interfacial friction factor correlation are developed. The model predictions are compared with the pure steam data, and the agreement is satisfactory.

Oh, Seungmin; Revankar, Shripad T. [Purdue University (United States)

2005-10-15

416

Anomalous scaling in passive scalar advection from anomalous exponents in polymer partition function  

NASA Astrophysics Data System (ADS)

The problem of turbulence in liquids is addressed by a recent theory of Brownian relativity. It relates the dynamics of the liquid molecules to the static properties of macromolecules dispersed in a polymer solution. As such, features of the random molecular motion in a turbulent fluid should also be recovered from a (simpler) statistical mechanics analysis of chain configurations. We took advantage of a covariant Vineyard-like approximation, formerly derived to get the van Hove's distribution functions in a dilute polymer solution. It points out an extended Gaussian statistics for correlated systems and a condition of probability conservation, exploited here to deal with a turbulently advected passive scalar by the partition function of a polymer network of given topology. Working with star polymers, a semi-heuristic closed-form expression for the anomalous scaling of passive structure exponents is derived. It agrees with earlier numerical simulations, encouraging the search of turbulent patterns "within" static chain configurations alone.

Mezzasalma, Stefano A.

2007-04-01

417

A Passive Probe for Subsurface Oceans and Liquid Water in Jupiter's Icy Moons  

NASA Astrophysics Data System (ADS)

We present a method for passive detection of subsurface oceans and liquid water in Jovian icy moons using Jupiter's decametric radio emission (DAM). The DAM flux density exceeds 3,000 times the galactic background in the neighborhood of the Jovian icy moons, providing a signal that could be used for passive radio sounding. An instrument located between the icy moon and Jupiter could sample the DAM emission along with its echoes reflected in the ice layer of the target moon. Cross-correlating the direct emission with the echoes would provide a measurement of the subsurface ocean depth along with the dielectric properties of the ice shell. The technique is complementary to ice penetrating radar measurements in that it works best where interference due to Jupiter's strong decametric emission is the strongest.

Romero-Wolf, Andrew; Vance, Steve; Maiwald, Frank; Ries, Paul; Liewer, Kurt

2014-11-01

418

Air sampling of fungal spores on filters. An investigation on passive sampling and viability.  

PubMed

In this study, glycerol was tested as a collection substrate for passive bioaerosol sampling. Filters (mixed cellulose acetate and nitrate) were soaked in glycerol and exposed for an aerosol from three different fungal species: Penicillum commune, Aspergillus versicolor and Paecilomyces variotii. The passive sampling method was compared with a closed-face polycarbonate filter sampling method. Exposure was performed in an exposure chamber. The total number of spores was determined by microscopic techniques, and the cultivable number was determined by cultivation on Malt Extract Agar dishes. The glycerol soaked filter demonstrated a good correlation with the closed-face sampler with regard to the total count. Spores stored in a pumped filter cassette were not affected by storage for up to 7 days. On the other hand, the culturability of the spores was markedly decreased after 1 day when stored on glycerol soaked filters. PMID:11529137

Näsman, A; Blomquist, G; Levin, J O

1999-08-01

419

Incentive Relativity: Gene-environment Interactions  

E-print Network

B (2013). Animal models of extinction-induced depression:extinction effect (PREE), and the partial reinforcement contrast effect (PRCE), constitute some animalextinction, and partial reinforcement contrast procedures, and focusing on psychogenetic studies conducted in nonhuman animals.

Torres, Carmen; Sabariego, Marta

2014-01-01

420

Gene-environment interactions in genetic epidemiology  

E-print Network

and the use of oral contraceptives. The methods developed here are especially appropriate for this data, as over half of all of the study participants have unknown genotype. 5 CHAPTER II JOINT LINKAGE DISEQUILIBRIUM AND LINKAGE MAPPING FOR COMPLEX PEDIGREES 2... the interaction between either a BRCA1 or BRCA2 mutation and both oral contraceptive usage and parity. Additionally, many other covariates, including age, family history of breast and ovarian cancer, personal history of breast cancer, history of gynecological...

Spinka, Christine Marie

2005-02-17

421

Breast Cancer Risk - Genes, Environment and Clinics  

PubMed Central

The information available about breast cancer risk factors has increased dramatically during the last 10 years. In particular, studies of low-penetrance genes and mammographic density have improved our understanding of breast cancer risk. In addition, initial steps have been taken in investigating interactions between genes and environmental factors. This review concerns with actual data on this topic. Several genome-wide association studies (GWASs) with a case–control design, as well as large-scale validation studies, have identified and validated more than a dozen single nucleotide polymorphisms (SNPs) associated with breast cancer risk. They are located not only in or close to genes known to be involved in cancer pathogenesis, but also in genes not previously associated with breast cancer pathogenesis, or may even not be related to any genes. SNPs have also been identified that alter the lifetime risk in BRCA mutation carriers. With regard to nongenetic risk factors, studies of postmenopausal hormone replacement therapy (HRT) have revealed important information on how to weigh up the risks and benefits of HRT. Mammographic density (MD) has become an accepted and important breast cancer risk factor. Lifestyle and nutritional considerations have become an integral part of most studies of breast cancer risk, and some improvements have been made in this field as well. More than 10 years after the publication of the first breast cancer prevention studies with tamoxifen, other substances such as raloxifene and aromatase inhibitors have been investigated and have also been shown to have preventive potential. Finally, mammographic screening systems have been implemented in most Western countries during the last decade. These may be developed further by including more individualized methods of predicting the patient?s breast cancer risk.

Fasching, P. A.; Ekici, A. B.; Adamietz, B. R.; Wachter, D. L.; Hein, A.; Bayer, C. M.; Haberle, L.; Loehberg, C. R.; Jud, S. M.; Heusinger, K.; Rubner, M.; Rauh, C.; Bani, M. R.; Lux, M. P.; Schulz-Wendtland, R.; Hartmann, A.; Beckmann, M. W.

2011-01-01

422

Gene environment interactions in bipolar disorder.  

PubMed

It has been estimated that the heritable component of bipolar disorder ranges between 80 and 90%. However, even genome-wide association studies explain only a fraction of phenotypic variability not resolving the problem of "lost heritability". Although direct evidence for epigenetic dysfunction in bipolar disorder is still limited, methodological technologies in epigenomic profiling have advanced, offering even single cell analysing and resolving the problem of cell heterogeneity in epigenetics research. Gene overlapping with other mental disorders represents another problem in identifying potential susceptibility genes in bipolar disorder. Better understanding of the interplay between multiple environmental and genetic factors involved in the patogenesis of bipolar disorder could provide relevant information for treatment of patients with this complex disorder. Future studies on the role of these factors in psychopathological conditions, subphenotypes and endophenotypes may greatly benefit by using more precise clinical data and a combined approach with multiple research tools incorporated into a single study. PMID:21894111

Pregelj, Peter

2011-09-01

423

Genes, Environment, and Race: Quantitative Genetic Approaches  

Microsoft Academic Search

Understanding the origins of racial health disparities is currently a central focus of health-oriented funding agencies and the health policy community. In particular, the role of genetics in the origin of racial health disparities is receiving growing attention and has been susceptible to considerable misinterpretation. In this article, the authors provide a basic discussion about the concept of genes and

Keith E. Whitfield; Gerald McClearn

2005-01-01

424

Passive coolers for pre-cooling of JT loops for deep space infrared imaging applications  

NASA Astrophysics Data System (ADS)

Infrared instruments (IR) for deep space imaging missions, such as the James Webb Space Telescope (JWST) and Planck, require cryogenic cooling for proper operation of their focal plane arrays (FPA) in far infrared and sub-millimeter wavelength ranges. The FPA is sometimes located meters away from the spacecraft. To meet such remote cooling requirement, a Joule-Thomson (J-T) loop becomes a convenient choice for either direct cooling for the FPA or for serving as a heat sink for a cascade cooling system. The refrigerant lines of the JT loop inevitably suffer parasitic heat leak primarily due to IR backload as they traverse from the spacecraft to the FPA. An actively cooled JT loop using a mechanical pre-cooler located at the spacecraft will experience the highest parasitic heat leak since the lines are cold through the entire length whereas a passively cooled JT loop can utilize a number of radiators to cool the lines down gradually in stages and hence reduce the heat leak. In addition to savings in power and mass, a passive cooler offers consistent and predictable performance with practically no performance degradation in a thermally stable orbit, such as one around the Sun-Earth L2 point. Passive coolers are less popular in low temperature applications when their cooling capacity diminishes rapidly in proportion to T4 until the temperature reaches a point where either the parasitic heat leak becomes so significant or its size becomes so excessive that the passive cooling scheme becomes impractical. Despite the limited capacity, passive cooling may still prove to be a viable alternative to active cooling depending on the operating temperature and heat dissipation rate of the FPA. The current effort aims at evaluating the merit of using passive coolers as an alternative to using a mechanical cooler for pre-cooling of a JT loop for remote IR instrument cooling. A parametric study is conducted to explore the merits of passive cooling of a JT loop in a temperature range below 30 K. Correlations between cooling capacity, heat leak from supporting structure, and the operating temperature are investigated to provide design guidelines. Radiator staging options will also be presented and discussed.

Zhang, Burt; Larson, Melora; Rodriguez, Jose

2010-09-01

425

Cooperative passive-solar commercial retrofit  

NASA Astrophysics Data System (ADS)

The primary objectives of this project were: the conversion of an existing south-facing storefront into a trombe'-wall passive solar collector, the sharing of information on simple low-cost energy alternatives with the local community, and the reduction of the store building's dependence on non-renewable fossil fuel for space heating. Six 6' wide pre-assembled collector glazing panels were mounted on a 12' high by 36' long portion of the south-facing masonry wall. Vent-holes were cut through the wall at each panel to provide air inlets and outlets for the collector and monitoring equipment was installed to record performance. A series of hands-on construction workshops were attended by Co-op and community members. During these sessions, collector components were assembled. The panels were installed on April 22, 1981 in celebration of Earth Day. Additional sessions were held to complete the project, make necessary modifications and install sensors. Project personnel participated in several energy-education activities, including workshops, seminars and alternative energy home tours. A community-based energy resource council was founded with the assistance of several key Co-op project members and a fully-illustrated How-To manual, entitled Passive Solar Collector: A Trombe'-Wall Retrofit Guide was published. Finally, a variety of energy conservation measures were undertaken. These included a new airlock store entry, insulated store ceiling, destratification ceiling fans and wood-burning furnaces have combined with the passive solar collector to substantially reduce the use of fuel oil for heat.

Brown, W. T.

1982-12-01

426

Passive solar concepts for multistory buildings  

SciTech Connect

Multistory buildings long in the east-west direction and short in the north-south direction offer good opportunity for passive solar application. If each unit within the building is designed so that the Solar Savings Fraction is the same, each will respond to the weather the same way and no unit-to-unit heat distribution is needed. A numerical example for Denver is given indicating excellent thermal performance and a several-day thermal response time. Solutions involving distribution of heat from unit to unit are also discussed as well as top-floor and south-wall variations.

Balcomb, J.D.

1982-01-01

427

Passivation-free solid state battery  

Microsoft Academic Search

This invention pertains to passivation-free solid-state rechargeable batteries composed of Li.sub.4 Ti.sub.5 O.sub.12 anode, a solid polymer electrolyte and a high voltage cathode. The solid polymer electrolyte comprises a polymer host, such as polyacrylonitrile, poly(vinyl chloride), poly(vinyl sulfone), and poly(vinylidene fluoride), plasticized by a solution of a Li salt in an organic solvent. The high voltage cathode includes LiMn.sub.2 O.sub.4,

Kuzhikalail M. Abraham; Dharmasena Peramunage

1998-01-01

428

Passive vibration isolation using a Roberts linkage  

NASA Astrophysics Data System (ADS)

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 remaining four isolation stages of the AIGO vibration isolator chain. A description of the device together with a theoretical model and its measured isolation performance are presented. With the current setup, we obtained 32 dB of isolation at 1 Hz.

Garoi, F.; Winterflood, J.; Ju, L.; Jacob, J.; Blair, D. G.

2003-07-01

429

Apparatus for passive removal of subsurface contaminants  

DOEpatents

An apparatus is provided which passively removes contaminated gases from a subsurface. The apparatus includes a riser pipe extending into a subsurface which has an exterior end in fluid communication with a valve. When well pressure is greater than atmospheric pressure, the valve opens to release contaminants into the atmosphere, and when well pressure is less than atmospheric pressure, the valve closes to prevent flow of air into the well. The valve assembly of the invention comprises a lightweight ball which is lifted from its valve seat with a slight pressure drop between the well and the atmosphere.

Pemberton, Bradley E. (Aiken, SC); May, Christopher P. (Fairfax, VA); Rossabi, Joseph (Aiken, SC)

1997-01-01

430

Passive Wireless SAW Sensors for IVHM  

NASA Technical Reports Server (NTRS)

NASA aeronautical programs require integrated vehicle health monitoring (IVHM) to ensure the safety of the crew and the vehicles. Future IVHM sensors need to be small, light weight, inexpensive, and wireless. Surface acoustic wave (SAW) technology meets all of these constraints. In addition it operates in harsh environments and over wide temperature ranges, and it is inherently radiation hardened. This paper presents a survey of research opportunities for universities and industry to develop new sensors that address anticipated IVHM needs for aerospace vehicles. Potential applications of passive wireless SAW sensors from ground testing to high altitude aircraft operations are presented, along with some of the challenges and issues of the technology.

Wilson, William C.; Perey, Daniel F.; Atkinson, Gary M.; Barclay, Rebecca O.

2008-01-01

431

Passive solar concepts for multistory buildings  

NASA Astrophysics Data System (ADS)

Multistory buildings long in the east-west direction and short in the north-south direction offer good opportunity for passive solar application. If each unit within the building is designed so that the solar savings fraction is the same, each will respond to the weather the same way and no unit to unit heat distribution is needed. A numerical example for Denver is given indicating excellent thermal performance and a several day thermal response time. Solutions involving distribution of heat from unit to unit are also discussed as well as top floor and south wall variations.

Balcomb, J. D.

432

Development of a Multiband Passive Scanning Imager  

NASA Astrophysics Data System (ADS)

A passive scanning imaging system that can operate at multiband spectra covering infrared, THz, and MMW regions has been developed. A high-quality optical system, which consists of a scanning swing planar mirror and a concave mirror, is used to be compatible in different frequency ranges. An elliptical aperture is opened at the center of the swing mirror to allow the focused light to pass through. Four types of detectors that contain two homemade bolometric detectors are used to distinguish images that range from infrared to millimeter waves. Our results demonstrate that the reflection-type imaging system performs well and exhibits compatibility to operate at different frequencies.

Tong, Jinchao; Huang, Zhingming; Hou, Yun; Zhang, Leibo; Zhou, Wei; Huang, Jingguo; Chu, Junhao

2013-04-01

433

Apparatus for passive removal of subsurface contaminants  

DOEpatents

An apparatus is provided which passively removes contaminated gases from a subsurface. The apparatus includes a riser pipe extending into a subsurface which has an exterior end in fluid communication with a valve. When well pressure is greater than atmospheric pressure, the valve opens to release contaminants into the atmosphere, and when well pressure is less than atmospheric pressure, the valve closes to prevent flow of air into the well. The valve assembly of the invention comprises a lightweight ball which is lifted from its valve seat with a slight pressure drop between the well and the atmosphere. 7 figs.

Pemberton, B.E.; May, C.P.; Rossabi, J.

1997-06-24

434

Passivation-free solid state battery  

DOEpatents

This invention pertains to passivation-free solid-state rechargeable batteries composed of Li{sub 4}Ti{sub 5}O{sub 12} anode, a solid polymer electrolyte and a high voltage cathode. The solid polymer electrolyte comprises a polymer host, such as polyacrylonitrile, poly(vinyl chloride), poly(vinyl sulfone), and poly(vinylidene fluoride), plasticized by a solution of a Li salt in an organic solvent. The high voltage cathode includes LiMn{sub 2}O{sub 4}, LiCoO{sub 2}, LiNiO{sub 2} and LiV{sub 2}O{sub 5} and their derivatives. 5 figs.

Abraham, K.M.; Peramunage, D.

1998-06-16

435

Passivation-free solid state battery  

DOEpatents

This invention pertains to passivation-free solid-state rechargeable batteries composed of Li.sub.4 Ti.sub.5 O.sub.12 anode, a solid polymer electrolyte and a high voltage cathode. The solid polymer electrolyte comprises a polymer host, such as polyacrylonitrile, poly(vinyl chloride), poly(vinyl sulfone), and poly(vinylidene fluoride), plasticized by a solution of a Li salt in an organic solvent. The high voltage cathode includes LiMn.sub.2 O.sub.4, LiCoO.sub.2, LiNiO.sub.2 and LiV.sub.2 O.sub.5 and their derivatives.

Abraham, Kuzhikalail M. (Needham, MA); Peramunage, Dharmasena (Norwood, MA)

1998-01-01

436

SOLCOST-PASSIVE solar energy design program: User's Guide  

SciTech Connect

The SOLCOST-PASSIVE solar energy design program is a public domain interactive computer design tool intended for use by non-thermal specialists to size passive solar systems with a methodology based on the Los Alamos Solar Load Ratio method. A life cycle savings analysis is included in the program. An overview of SOLCOST-PASSIVE capabilities and the Solar Load Ratio method which it is based on is presented. A detailed guide to the SOLCOST-PASSIVE input parameters is given. Sample problems showing typical execution sessions and the resulting SOLCOST-PASSIVE output are included. Appendices A thru D provide details on the SLR method and the life cycle savings methodology of SOLCOST-PASSIVE. (MHR)

Not Available

1980-09-01

437

Passive cooling during transport of asphyxiated term newborns  

PubMed Central

Objective To evaluate the efficacy and safety of passive cooling during transport of asphyxiated newborns. Study Design Retrospective medical record review of newborns with perinatal asphyxia transported for hypothermia between July 2007 and June 2010. Results Forty-three newborns were transported, 27 of whom were passively cooled. Twenty (74%) passively cooled newborns arrived with axillary temperature between 32.5 and 34.5 °C. One newborn (4%) arrived with a subtherapeutic temperature, and 6 (22%) had temperatures >34.5 °C. Time from birth to hypothermia was significantly shorter among passively cooled newborns compared with newborns not cooled (215 vs. 327 minutes, p<0.01), even though time from birth to arrival was similar (252 vs. 259 minutes, p=0.77). There were no significant adverse events related to passive cooling. Conclusions Exclusive passive cooling for hypoxic-ischemic encephalopathy results in significantly earlier achievement of effective therapeutic hypothermia without significant adverse events. PMID:23154670

O'Reilly, Deirdre; Labrecque, Michelle; O'Melia, Michael; Bacic, Janine; Hansen, Anne; Soul, Janet S

2014-01-01

438

Effects of dissolved oxygen on passive behavior of stainless alloys  

Microsoft Academic Search

A potential-control circuit has been devised to measure passive-current (corrosion rate) on stainless alloys in conditions simulating the usual noble drift of the open-circuit corrosion potential in the presence of passivating dissolved oxidizers. Open-circuit corrosion potential and passive-current decay were measured with and without dissolved oxygen in dilute sulfuric acid solutions as a function of time on austenitic stainless steel

K. S. Raja; D. A. Jones

2006-01-01

439

A new algorithm for passive millimeter-wave image enhancement  

Microsoft Academic Search

Passive millimeter-wave image are heavily blurred due to the low-pass filter effect of antenna and the influence of noise. Aimed the problem, an improved method using partial differential equations applied to passive millimeter-wave image high-resolution is proposed. Based on nonlinear bidirectional Laplace filter algorithm, a new passive millimeter-wave image enhancement is proposed. For different characteristics regions of image, using different

Jie Yang; Jianguo Wang; Liangchao Li

2010-01-01

440

Control of a passively steered rover using 3-D kinematics  

Microsoft Academic Search

This paper describes and evaluates a 3-D kine- matic controller for passively-steered rovers. Passively-steered rovers have no steering motors, but rely on differential wheel velocities to change the axle steer angles. This passive steering design is reliable and efficient but more challenging to control than powered steering designs, especially when driving on rough terrain. A controller based on 2-D kinematics

Neal Seegmiller; David Wettergreen

2011-01-01