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1

Childhood Temperament: Passive Gene-Environment Correlation, Gene-Environment Interaction, and the Hidden Importance of the Family Environment  

PubMed Central

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

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

2013-01-01

2

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

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: Difficulties and a Natural Experiment–Based Strategy  

PubMed Central

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

Li, Jiang; Liu, Hexuan; Guo, Guang

2013-01-01

6

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

7

The genetics of music accomplishment: Evidence for gene-environment correlation and interaction.  

PubMed

Theories of skilled performance that emphasize training history, such as K. Anders Ericsson and colleagues' deliberate-practice theory, have received a great deal of recent attention in both the scientific literature and the popular press. Twin studies, however, have demonstrated evidence for moderate-to-strong genetic influences on skilled performance. Focusing on musical accomplishment in a sample of over 800 pairs of twins, we found evidence for gene-environment correlation, in the form of a genetic effect on music practice. However, only about one quarter of the genetic effect on music accomplishment was explained by this genetic effect on music practice, suggesting that genetically influenced factors other than practice contribute to individual differences in music accomplishment. We also found evidence for gene-environment interaction, such that genetic effects on music accomplishment were most pronounced among those engaging in music practice, suggesting that genetic potentials for skilled performance are most fully expressed and fostered by practice. PMID:24957535

Hambrick, David Z; Tucker-Drob, Elliot M

2015-02-01

8

Latent variable models for gene-environment interactions in longitudinal studies with multiple correlated exposures.  

PubMed

Many existing cohort studies designed to investigate health effects of environmental exposures also collect data on genetic markers. The Early Life Exposures in Mexico to Environmental Toxicants project, for instance, has been genotyping single nucleotide polymorphisms on candidate genes involved in mental and nutrient metabolism and also in potentially shared metabolic pathways with the environmental exposures. Given the longitudinal nature of these cohort studies, rich exposure and outcome data are available to address novel questions regarding gene-environment interaction (G × E). Latent variable (LV) models have been effectively used for dimension reduction, helping with multiple testing and multicollinearity issues in the presence of correlated multivariate exposures and outcomes. In this paper, we first propose a modeling strategy, based on LV models, to examine the association between repeated outcome measures (e.g., child weight) and a set of correlated exposure biomarkers (e.g., prenatal lead exposure). We then construct novel tests for G × E effects within the LV framework to examine effect modification of outcome-exposure association by genetic factors (e.g., the hemochromatosis gene). We consider two scenarios: one allowing dependence of the LV models on genes and the other assuming independence between the LV models and genes. We combine the two sets of estimates by shrinkage estimation to trade off bias and efficiency in a data-adaptive way. Using simulations, we evaluate the properties of the shrinkage estimates, and in particular, we demonstrate the need for this data-adaptive shrinkage given repeated outcome measures, exposure measures possibly repeated and time-varying gene-environment association. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25545894

Tao, Yebin; Sánchez, Brisa N; Mukherjee, Bhramar

2015-03-30

9

Observed positive parenting behaviors and youth genotype: Evidence for gene–environment correlations and moderation by parent personality traits  

PubMed Central

Gene–environment correlations (rGE) have been demonstrated in behavioral genetic studies, but rGE have proven elusive in molecular genetic research. Significant gene–environment correlations may be difficult to detect because potential moderators could reduce correlations between measured genetic variants and the environment. Molecular genetic studies investigating moderated rGE are lacking. This study examined associations between child catechol-O-methyltransferase genotype and aspects of positive parenting (responsiveness and warmth), and whether these associations were moderated by parental personality traits (neuroticism and extraversion) among a general community sample of third, sixth, and ninth graders (N = 263) and their parents. Results showed that parent personality traits moderated the rGE association between youths’ genotype and coded observations of positive parenting. Parents with low levels of neuroticism and high levels of extraversion exhibited greater sensitive responsiveness and warmth, respectively, to youth with the valine/valine genotype. Moreover, youth with this genotype exhibited lower levels of observed anger. There was no association between the catechol-O-methyltransferase genotype and parenting behaviors for parents high on neuroticism and low on extraversion. Findings highlight the importance of considering moderating variables that may influence child genetic effects on the rearing environment. Implications for developmental models of maladaptive and adaptive child outcomes, and interventions for psychopathology, are discussed within a developmental psychopathology framework. PMID:23398761

OPPENHEIMER, CAROLINE W.; HANKIN, BENJAMIN L.; JENNESS, JESSICA L.; YOUNG, JAMI F.; SMOLEN, ANDREW

2013-01-01

10

A latent variable approach to study gene-environment interactions in the presence of multiple correlated exposures  

PubMed Central

Summary Many existing cohort studies initially designed to investigate disease risk as a function of environmental exposures have collected genomic data in recent years with the objective of testing for gene-environment interaction (G × E) effects. In environmental epidemiology, interest in G × E arises primarily after a significant effect of the environmental exposure has been documented. Cohort studies often collect rich exposure data, as a result, assessing G × E effects in the presence of multiple exposure markers further increases the burden of multiple testing, an issue already present in both genetic and environment health studies. Latent variable (LV) models have been used in environmental epidemiology to reduce dimensionality of the exposure data, gain power by reducing multiplicity issues via condensing exposure data, and avoid collinearity problems due to presence of multiple correlated exposures. We extend the LV framework to characterize gene-environment interaction in presence of multiple correlated exposures and genotype categories. Further, similar to what has been done in case-control G × E studies, we use the assumption of gene-environment (G-E) independence to boost the power of tests for interaction. The consequences of making this assumption, or the issue of how to explicitly model G-E association has not been previously investigated in LV models. We postulate a hierarchy of assumptions about the LV model regarding the different forms of G-E dependence and show that making such assumptions may influence inferential results on the G, E, and G × E parameters. We implement a class of shrinkage estimators to data adaptively trade-off between the most restrictive to most flexible form of G-E dependence assumption and note that such class of compromise estimators can serve as a benchmark of model adequacy in LV models. We demonstrate the methods with an example from the Early Life Exposures in Mexico City to Neuro-Toxicants (ELEMENT) study of lead exposure, iron metabolism genes, and birth weight. PMID:21955029

Kang, Shan; Mukherjee, Bhramar

2015-01-01

11

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

12

The Interacting Effect of the BDNF Val66Met Polymorphism and Stressful Life Events on Adolescent Depression Is Not an Artifact of Gene-Environment Correlation: Evidence from a Longitudinal Twin Study  

ERIC Educational Resources Information Center

Background: Confounding introduced by gene-environment correlation (rGE) may prevent one from observing a true gene-environment interaction (G × E) effect on psychopathology. The present study investigated the interacting effect of the BDNF Val66Met polymorphism and stressful life events (SLEs) on adolescent depression while controlling for the…

Chen, Jie; Li, Xinying; McGue, Matt

2013-01-01

13

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

14

Gene-Environment Interdependence  

ERIC Educational Resources Information Center

Behavioural genetics was initially concerned with partitioning population variance into that due to genetics and that due to environmental influences. The implication was that the two were separate and it was assumed that gene-environment interactions were usually of so little importance that they could safely be ignored. Theoretical…

Rutter, Michael

2007-01-01

15

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

16

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

17

Gene-Environment Interplay in Twin Models  

PubMed Central

In this article, we respond to Shultziner’s critique that argues that identical twins are more alike not because of genetic similarity, but because they select into more similar environments and respond to stimuli in comparable ways, and that these effects bias twin model estimates to such an extent that they are invalid. The essay further argues that the theory and methods that undergird twin models, as well as the empirical studies which rely upon them, are unaware of these potential biases. We correct this and other misunderstandings in the essay and find that gene-environment (GE) interplay is a well-articulated concept in behavior genetics and political science, operationalized as gene-environment correlation and gene-environment interaction. Both are incorporated into interpretations of the classical twin design (CTD) and estimated in numerous empirical studies through extensions of the CTD. We then conduct simulations to quantify the influence of GE interplay on estimates from the CTD. Due to the criticism’s mischaracterization of the CTD and GE interplay, combined with the absence of any empirical evidence to counter what is presented in the extant literature and this article, we conclude that the critique does not enhance our understanding of the processes that drive political traits, genetic or otherwise. PMID:24808718

Hatemi, Peter K.

2013-01-01

18

Genes, Environment, and Human Behavior.  

ERIC Educational Resources Information Center

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

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

19

Correlation between lidar-derived intensity and passive optical imagery  

NASA Astrophysics Data System (ADS)

When LiDAR data are collected, the intensity information is recorded for each return, and can be used to produce an image resembling those acquired by passive imaging sensors. This research evaluated LiDAR intensity data to determine its potential for use as baseline imagery where optical imagery are unavailable. Two airborne LiDAR datasets collected at different point densities and laser wavelengths were gridded and compared with optical imagery. Optech Orion C200 laser data were compared with a corresponding 1541 nm spectral band from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). Optech ALTM Gemini LiDAR data collected at 1064 nm were compared to the WorldView-2 (WV-2) 949 - 1043 nm NIR2 band. Intensity images were georegistered and spatially resampled to match the optical data. The Pearson Product Moment correlation coefficient was calculated between datasets to determine similarity. Comparison for the full LiDAR datasets yielded correlation coefficients of approximately 0.5. Because LiDAR returns from vegetation are known to be highly variable, a Normalized Difference Vegetation Index (NDVI) was calculated utilizing the optical imagery, and intensity and optical imagery were separated into vegetation and nonvegetation categories. Comparison of the LiDAR intensity for non-vegetated areas to the optical imagery yielded coefficients greater than 0.9. These results demonstrate that LiDAR intensity data may be useful in substituting for optical imagery where only LiDAR is available.

Metcalf, Jeremy P.; Kim, Angela M.; Kruse, Fred A.; Olsen, Richard C.

2014-06-01

20

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

21

Operating Characteristics of Statistical Methods for Detecting Gene-by-Measured Environment Interaction in the Presence of Gene-Environment Correlation under Violations of Distributional Assumptions.  

PubMed

Accurately identifying interactions between genetic vulnerabilities and environmental factors is of critical importance for genetic research on health and behavior. In the previous work of Van Hulle et al. (Behavior Genetics, Vol. 43, 2013, pp. 71-84), we explored the operating characteristics for a set of biometric (e.g., twin) models of Rathouz et al. (Behavior Genetics, Vol. 38, 2008, pp. 301-315), for testing gene-by-measured environment interaction (GxM) in the presence of gene-by-measured environment correlation (rGM) where data followed the assumed distributional structure. Here we explore the effects that violating distributional assumptions have on the operating characteristics of these same models even when structural model assumptions are correct. We simulated N = 2,000 replicates of n = 1,000 twin pairs under a number of conditions. Non-normality was imposed on either the putative moderator or on the ultimate outcome by ordinalizing or censoring the data. We examined the empirical Type I error rates and compared Bayesian information criterion (BIC) values. In general, non-normality in the putative moderator had little impact on the Type I error rates or BIC comparisons. In contrast, non-normality in the outcome was often mistaken for or masked GxM, especially when the outcome data were censored. PMID:25584702

Van Hulle, Carol A; Rathouz, Paul J

2015-02-01

22

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

23

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

24

Multispectral passive microwave correlations with an antecedent precipitation index using the Nimbus 7 SMMR  

E-print Network

MULTISPECTRAL PASSIVE MICROWAVE CORRELATIONS WITH AN ANTECEDENT PRECIPITATION INDEX USING THE NIMBUS 7 SMMR A THESIS by GREGORY DELFIN WILKE Submitted to the Graduate College of Texas A&N University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1984 Major Subject: Meteorology MULT ISPECTRAL PASSIVE MICROWAVE CORRELATIONS WITH AN ANTECEDENT PRECIPITATION INDEX USING THE NIMBUS 7 SMMR A Thesis by GREGORY DELFIN WILKE Approved as to style and content by...

Wilke, Gregory Delfin

1984-01-01

25

Gene-Environment Interplay between Number of Friends and Prosocial Leadership Behavior in Children  

ERIC Educational Resources Information Center

Enriched environments may moderate the effect of genetic factors on prosocial leadership (gene-environment interaction, G × E). However, positive environmental experiences may also themselves be influenced by a genetic disposition for prosocial leadership (gene-environment correlation, rGE). Relating these processes to friendships, the present…

Rivizzigno, Alessandra S.; Brendgen, Mara; Feng, Bei; Vitaro, Frank; Dionne, Ginette; Tremblay, Richard E.; Boivin, Michel

2014-01-01

26

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

27

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

28

Benefits of Time Correlation Measurements for Passive Screening  

NASA Astrophysics Data System (ADS)

The “FLASH Portals Project” is a collaboration between Arktis Radiation Detectors Ltd (CH), the Atomic Weapons Establishment (UK), and the Joint Research Centre (European Commission), supported by the Technical Support Working Group (TSWG). The program's goal was to develop and demonstrate a technology to detect shielded special nuclear materials (SNM) more efficiently and less ambiguously by exploiting time correlation. This study presents experimental results of a two-sided portal monitor equipped with in total 16 4He fast neutron detectors as well as four polyvinyltoluene (PVT) plastic scintillators. All detectors have been synchronized to nanosecond precision, thereby allowing the resolution of time correlations from timescales of tens of microseconds (such as (n, ?) reactions) down to prompt fission correlations directly. Our results demonstrate that such correlations can be detected in a typical radiation portal monitor (RPM) geometry and within operationally acceptable time scales, and that exploiting these signatures significantly improves the performance of the RPM compared to neutron counting. Furthermore, the results show that some time structure remains even in the presence of heavy shielding, thus significantly improving the sensitivity of the detection system to shielded SNM.

Murer, David; Blackie, Douglas; Peerani, Paolo

2014-02-01

29

Passive Sensor Imaging Using Cross Correlations of Noisy Signals in a Scattering Medium  

Microsoft Academic Search

It is well known that the travel time or even the full Green's function between two passive sensors can be estimated from the cross correlation of recorded signal amplitudes generated by ambient noise sources. It is also known that the direction of the energy flux from the noise sources affects the estimation of the travel time. Using the stationary phase

G. Papanicolaou; J. Garnier

2008-01-01

30

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

31

GeneEnvironment Interplay, Family Relationships, and Child Adjustment  

PubMed Central

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

Horwitz, Briana N.; Neiderhiser, Jenae M.

2011-01-01

32

Gene-Environment Studies and Borderline Personality Disorder: A Review  

PubMed Central

We review recent gene-environment studies relevant to borderline personality disorder, including those focusing on impulsivity, emotion sensitivity, suicidal behavior, aggression and anger, and the borderline personality phenotype itself. Almost all the studies reviewed suffered from a number of methodological and statistical problems, limiting the conclusions that currently can be drawn. The best evidence to date supports a gene-environment correlation (rGE) model for borderline personality traits and a range of adverse life events, indicating that those at risk for BPD are also at increased risk for exposure to environments that may trigger BPD. We provide suggestions regarding future research on GxE interaction and rGE effects in borderline personality. PMID:23250817

Carpenter, Ryan W.; Tomko, Rachel L.; Boomsma, Dorret I.

2014-01-01

33

Passive dispersion analysis on a sea dike using cross-correlations and beamforming  

NASA Astrophysics Data System (ADS)

In order to passively infer the velocities of surface waves beneath a receiver array, we propose to apply beamforming on cross-correlated noise records. We test the method with synthetic signals generated for a variety of array geometries and noise distributions. We show that the use of cross-correlations cleans the dispersion diagram that would be obtained from a phase-shift analysis alone, by resolving ambiguities between the location of noise sources and the wave velocities. In particular, when nearby noise sources are present, accurate dispersion curves can be inferred from arrays possessing poor azimuthal coverages. This passive method is therefore appropriate for the monitoring of stiffness at the civil-engineering scale, where multiple isolated noise sources may be present and where the field geometry does not always allow to deploy circular arrays. We apply the method to field data obtained from a linear array installed on top of a sea dike. The seismic noise, recorded at high tide during 8 minutes, is essentially generated by impacts of sea waves. In contrast to a phase-shift analysis performed on the noise itself, we show that the use of cross-correlations allow to infer a dispersion curve consistent with an active hammer-shot measurement, in a larger frequency band, ranging from 5 to 55 Hz. This result opens the possibility of following passively the mechanical evolution of embankments on a daily basis.

Le Feuvre, Mathieu; Joubert, Anaëlle; Leparoux, Donatienne; Côte, Philippe

2014-05-01

34

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.

35

Why study gene-environment interactions?  

Technology Transfer Automated Retrieval System (TEKTRAN)

PURPOSE OF REVIEW: We examine the reasons for investigating gene-environment interactions and address recent reports evaluating interactions between genes and environmental modulators in relation to cardiovascular disease and its common risk factors. RECENT FINDINGS: Studies focusing on smoking, phy...

36

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.

37

Two-photon correlation and photon transport in disordered passive parity-time-symmetric lattices  

NASA Astrophysics Data System (ADS)

Two-photon correlation and photon transport in periodic and disordered passive parity-time-symmetric lattices are studied. A transition on two-photon quantum correlation is observed with the increase of the loss coefficient ? in such non-Hermitian lattices, and the introduction of lattice disorder prompts the occurrence of the transition. The unique loss-enhanced transmission and the associated critical point of loss coefficient ?T of the parity-time-symmetric lattice are also modified significantly by introducing lattice disorder. Our results show that the critical point ?T is brought forward and the loss-enhanced transmission effect is enhanced in the non-Hermitian lattices with off-diagonal lattice disorders, while the critical point ?T is delayed and the loss-enhanced transmission effect is suppressed by introducing diagonal disorder into the non-Hermitian lattices.

Xu, Lei; Dou, Yiling; Bo, Fang; Xu, Jingjun; Zhang, Guoquan

2015-02-01

38

Gene–environment interactions in psychiatry: joining forces with neuroscience  

Microsoft Academic Search

Gene–environment interaction research in psychiatry is new, and is a natural ally of neuroscience. Mental disorders have known environmental causes, but there is heterogeneity in the response to each causal factor, which gene–environment findings attribute to genetic differences at the DNA sequence level. Such findings come from epidemiology, an ideal branch of science for showing that gene–environment interactions exist in

Avshalom Caspi; Terrie E. Moffitt

2006-01-01

39

Gene-Environment Interplay in the Link of Friends' and Nonfriends' Behaviors with Children's Social Reticence in a Competitive Situation  

ERIC Educational Resources Information Center

This study used a genetically informed design to assess the effects of friends' and nonfriends' reticent and dominant behaviors on children's observed social reticence in a competitive situation. Potential gene-environment correlations (rGE) and gene-environment interactions (GxE) in the link between (a) friends' and…

Guimond, Fanny-Alexandra; Brendgen, Mara; Vitaro, Frank; Forget-Dubois, Nadine; Dionne, Ginette; Tremblay, Richard E.; Boivin, Michel

2014-01-01

40

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

41

Gene-Environment Interaction in Psychological Traits and Disorders  

PubMed Central

There has been an explosion of interest in studying gene-environment interactions (GxE) as they relate to the development of psychopathol-ogy. In this article, I review different methodologies to study gene-environment interaction, providing an overview of methods from animal and human studies and illustrations of gene-environment interactions detected using these various methodologies. Gene-environment interaction studies that examine genetic influences as modeled latently (e.g., from family, twin, and adoption studies) are covered, as well as studies of measured genotypes. Importantly, the explosion of interest in gene-environment interactions has raised a number of challenges, including difficulties with differentiating various types of interactions, power, and the scaling of environmental measures, which have profound implications for detecting gene-environment interactions. Taking research on gene-environment interactions to the next level will necessitate close collaborations between psychologists and geneticists so that each field can take advantage of the knowledge base of the other. PMID:21219196

Dick, Danielle M.

2013-01-01

42

An automated cross-correlation based event detection technique and its application to surface passive data set  

USGS Publications Warehouse

In studies on heavy oil, shale reservoirs, tight gas and enhanced geothermal systems, the use of surface passive seismic data to monitor induced microseismicity due to the fluid flow in the subsurface is becoming more common. However, in most studies passive seismic records contain days and months of data and manually analysing the data can be expensive and inaccurate. Moreover, in the presence of noise, detecting the arrival of weak microseismic events becomes challenging. Hence, the use of an automated, accurate and computationally fast technique for event detection in passive seismic data is essential. The conventional automatic event identification algorithm computes a running-window energy ratio of the short-term average to the long-term average of the passive seismic data for each trace. We show that for the common case of a low signal-to-noise ratio in surface passive records, the conventional method is not sufficiently effective at event identification. Here, we extend the conventional algorithm by introducing a technique that is based on the cross-correlation of the energy ratios computed by the conventional method. With our technique we can measure the similarities amongst the computed energy ratios at different traces. Our approach is successful at improving the detectability of events with a low signal-to-noise ratio that are not detectable with the conventional algorithm. Also, our algorithm has the advantage to identify if an event is common to all stations (a regional event) or to a limited number of stations (a local event). We provide examples of applying our technique to synthetic data and a field surface passive data set recorded at a geothermal site.

Forghani-Arani, Farnoush; Behura, Jyoti; Haines, Seth S.; Batzle, Mike

2013-01-01

43

M&M: A Passive Toolkit for Measuring, Tracking, and Correlating Path Characteristics  

Microsoft Academic Search

This paper presents M&M, a passive measurement toolkit suitable for large-scale studies of Internet path characteristics. ThemultiQ tool uses equally-spaced mode gaps in TCP flows' packet interarrival time distributions to detect multiple bottle- neck capacities and their relative order. Unlike other passive tools, multiQ can discover up to three bottlenecks from the trace of a single flow, and can work

Sachin Katti; Dina Katabi; Chuck Blake; Eddie Kohler; Jacob Strauss

44

Gene-environment contributions to young adult sexual partnering.  

PubMed

To date, there has been relatively little work on gene-environment contributions to human sexuality, especially molecular analyses examining the potential contributions of specific polymorphisms in conjunction with life experiences. Using Wave III data from 717 heterozygous young adult sibling pairs included in the National Longitudinal Study of Adolescent Health, this article examined the combined contributions of attendance at religious services and three genetic polymorphisms (in the dopamine D4 receptor [DRD4]), dopamine D2 receptor [DRD2]), and the serotonin transporter promoter [5HTT]) to sensation seeking, a personality construct related to sexual behavior, and the number of vaginal sex partners participants had in the year before interview. Data analyses used an Allison mixed model approach to account for population stratification and correlated observations. DRD4 was unrelated to sensation seeking and to the number of sex partners in tests of both main effects and in interaction with religious attendance. Contrary to hypothesis, presence of the A1 DRD2 allele was associated with having had fewer sex partners in the past year. Associations between the 5HTT allele and sex partners varied by religious attendance, but again the patterns of associations were contrary to hypothesized relationships and were small in magnitude. These findings underscore the necessity of using more comprehensive multiple gene-multiple life experience approaches to investigations of complex behaviors such as sexual patterns. PMID:17186131

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

2007-08-01

45

Comparison of eye-safe solid state laser DIAL with passive gas filter correlation measurements from aircraft and spacecraft  

NASA Technical Reports Server (NTRS)

Differential Absorption Lidar (DIAL) using solid state Ti:sapphire lasers finds current application in the NASA/LASE Project for H2O vapor measurements in the approximately = 0.820 micron region for the lower and mid-troposphere and in potential future applications in planned measurements of the approximately = 0.940 micron region where both strong and weak absorption lines enables measurements throughout the troposphere and lower stratosphere. The challenge exists to perform measurements in the eye-safe greater than 1.5 micron region. A comparison between DIAL and passive Gas Filter Correlation Radiometer (GFCR) measurements is made. The essence of the differences in signal to noise ratio for DIAL and passive GFCR measurements is examined. The state of the art of lasers and optical parametric oscillators (OPO's) is discussed.

Hess, Robert V.; Staton, Leo D.; Wallio, H. Andrew; Wang, Liang-Guo

1992-01-01

46

Correlation between Abortion and Infertility among Nonsmoking Women with a History of Passive Smoking in Childhood and Adolescence  

PubMed Central

The aim of this study is to evaluate the correlation of exposing to the cigarette smoke in childhood and adolescence with infertility and abortion in women. This case-control study evaluated 178 women who had been attended to at the Amir-al-Momenin Hospital in Tehran in 2012-2013. Seventy-eight women with chief complaint of abortion, infertility, and missed abortion and 100 healthy women were considered as case and control groups, respectively. The tool was a questionnaire with two parts. In the first part demographic information was gathered and in the second part the information regarding the history of passive smoking in childhood and adolescence period, abortion, and infertility was gathered. The mean age in case and control groups was 26.24 ± 3.1 and 27.3 ± 4.2 years, respectively. The mean body mass index (BMI) was 25.74 ± 1.38?Kg/m2. Abortion rates among passive smoker and nonpassive smoker patients were statistically significant (P = 0.036). Based on findings of this study, the experience of being a passive smoker in childhood and adolescence in women will increase the risk of abortion and infertility in the future, which could be the reason to encourage the society to step back from smoking cigarettes.

Amirkhani, Jila; Yadollah-Damavandi, Soheila; Mirlohi, Seyed Mohammad-Javad; Nasiri, Seyede Mahnaz; Parsa, Yekta

2014-01-01

47

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

PubMed

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

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

2013-02-01

48

Calibration of passive microwave polarimeters that use hybrid coupler-based correlators  

Microsoft Academic Search

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

Jeffrey R. Piepmeier

2004-01-01

49

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

50

Optical reflectometry based on correlation detection and its application to the in-service monitoring of WDM passive optical network.  

PubMed

We propose and demonstrate a novel technique for measuring the distribution of the reflectivity along an optical fiber transmission line. Unlike the conventional optical time-domain reflectometer (OTDR), the proposed technique utilizes the data-modulated transmitter itself instead of the optical short-pulse source, and monitors the distribution of the back-reflected light by calculating the cross-correlation of the transmitted and back-reflected signals. In this paper, we describe the operating principle of the proposed technique and discuss its potential limitation on the dynamic range. We also show that this limitation can be mitigated by using the discrete-component elimination algorithm. In addition, we experimentally demonstrate that the proposed technique can be used for the in-service monitoring of the transmission fibers in a wavelength-division multiplexed passive optical network (WDM PON). PMID:19532785

Takushima, Y; Chung, Y C

2007-04-30

51

Understanding risk for psychopathology through imaging gene-environment interactions  

PubMed Central

Examining the interplay of genes, experience, and the brain is critical to understanding psychopathology. We review the recent gene-environment interaction (GxE) and imaging genetics literature with the goal of developing models to bridge these approaches within single imaging gene-environment interaction (IGxE) studies. We explore challenges inherent in both GxE and imaging genetics and highlight studies that address these limitations. In specifying IGxE models, we examine statistical methods for combining these approaches, and explore plausible biological mechanisms (e.g., epigenetics) through which these conditional mechanisms can be understood. Finally, we discuss the potential contribution that IGxE studies can make to understanding psychopathology and developing more personalized and effective prevention and treatment. PMID:21839667

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

2011-01-01

52

Gene–environment-wide association studies: emerging approaches  

Microsoft Academic Search

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 Review provides a tutorial on the available epidemiological designs and statistical analysis approaches for studying

Duncan Thomas

2010-01-01

53

Correlation between in vitro complement deposition and passive mouse protection of anti-pneumococcal surface protein a monoclonal antibodies.  

PubMed

The shortcomings of the licensed polysaccharide-based pneumococcal vaccine are driving efforts toward development of a protein-based vaccine that is serotype independent and effective in all age groups. An opsonophagocytic killing assay (OPKA) is used to evaluate the antibody response against polysaccharide-based pneumococcal vaccines. However, the OPKA is not reliable for noncapsular antigens. Thus, there is a need to develop an in vitro surrogate for protection for protein vaccine candidates like pneumococcal surface antigen A (PspA). PspA is a serologically variable cell surface virulence factor. Based on its sequence, PspA has been classified into families 1 (clade 1 and 2), 2 (clades 3, 4 and 5), and 3 (clade 6). Here, we report the characterization of 18 IgG anti-PspA monoclonal antibodies (anti-PspA(hkR36A) MAbs) generated from mice immunized with heat-killed strain R36A (clade 2). An enzyme-linked immunosorbent assay (ELISA)-based analysis of the reactivity of the MAbs with recombinant PspAs from the 6 clades indicated that they were family 1 specific. This was confirmed by flow cytometry using a hyperimmune serum generated against PspA from R36A. Eight MAbs that bind at least one clade 1- and clade 2-expressing strain were evaluated for complement deposition, bactericidal activity, and passive protection. The anti-PspA(hkR36A) MAb-dependent deposition of complement on pneumococci showed a positive correlation with passive protection against strain WU2 (r = 0.8783, P = 0.0041). All of our protective MAbs showed bactericidal activity; however, not all MAbs that exhibited bactericidal activity conferred protection in vivo. The protective MAbs described here can be used to identify conserved protection eliciting B cell epitopes for engineering a superior PspA-based vaccine. PMID:25410204

Khan, Naeem; Qadri, Raies Ahmad; Sehgal, Devinder

2015-01-01

54

Determining 252Cf source strength by absolute passive neutron correlation counting  

NASA Astrophysics Data System (ADS)

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

Croft, S.; Henzlova, D.

2013-06-01

55

Gene–Environment Interactions in Severe Mental Illness  

PubMed Central

Severe mental illness (SMI) is a broad category that includes schizophrenia, bipolar disorder, and severe depression. Both genetic disposition and environmental exposures play important roles in the development of SMI. Multiple lines of evidence suggest that the roles of genetic and environmental factors depend on each other. Gene–environment interactions may underlie the paradox of strong environmental factors for highly heritable disorders, the low estimates of shared environmental influences in twin studies of SMI, and the heritability gap between twin and molecular heritability estimates. Sons and daughters of parents with SMI are more vulnerable to the effects of prenatal and postnatal environmental exposures, suggesting that the expression of genetic liability depends on environment. In the last decade, gene–environment interactions involving specific molecular variants in candidate genes have been identified. Replicated findings include an interaction between a polymorphism in the AKT1 gene and cannabis use in the development of psychosis and an interaction between the length polymorphism of the serotonin transporter gene and childhood maltreatment in the development of persistent depressive disorder. Bipolar disorder has been underinvestigated, with only a single study showing an interaction between a functional polymorphism in the BDNF gene and stressful life events triggering bipolar depressive episodes. The first systematic search for gene–environment interactions has found that a polymorphism in CTNNA3 may sensitize the developing brain to the pathogenic effect of cytomegalovirus in utero, leading to schizophrenia in adulthood. Strategies for genome-wide investigations will likely include coordination between epidemiological and genetic research efforts, systematic assessment of multiple environmental factors in large samples, and prioritization of genetic variants. PMID:24860514

Uher, Rudolf

2014-01-01

56

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

57

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

58

A penalized robust method for identifying gene-environment interactions.  

PubMed

In high-throughput studies, an important objective is to identify gene-environment interactions associated with disease outcomes and phenotypes. Many commonly adopted methods assume specific parametric or semiparametric models, which may be subject to model misspecification. In addition, they usually use significance level as the criterion for selecting important interactions. In this study, we adopt the rank-based estimation, which is much less sensitive to model specification than some of the existing methods and includes several commonly encountered data and models as special cases. Penalization is adopted for the identification of gene-environment interactions. It achieves simultaneous estimation and identification and does not rely on significance level. For computation feasibility, a smoothed rank estimation is further proposed. Simulation shows that under certain scenarios, for example, with contaminated or heavy-tailed data, the proposed method can significantly outperform the existing alternatives with more accurate identification. We analyze a lung cancer prognosis study with gene expression measurements under the AFT (accelerated failure time) model. The proposed method identifies interactions different from those using the alternatives. Some of the identified genes have important implications. PMID:24616063

Shi, Xingjie; Liu, Jin; Huang, Jian; Zhou, Yong; Xie, Yang; Ma, Shuangge

2014-04-01

59

Music training and speech perception: a gene-environment interaction.  

PubMed

Claims of beneficial side effects of music training are made for many different abilities, including verbal and visuospatial abilities, executive functions, working memory, IQ, and speech perception in particular. Such claims assume that music training causes the associations even though children who take music lessons are likely to differ from other children in music aptitude, which is associated with many aspects of speech perception. Music training in childhood is also associated with cognitive, personality, and demographic variables, and it is well established that IQ and personality are determined largely by genetics. Recent evidence also indicates that the role of genetics in music aptitude and music achievement is much larger than previously thought. In short, music training is an ideal model for the study of gene-environment interactions but far less appropriate as a model for the study of plasticity. Children seek out environments, including those with music lessons, that are consistent with their predispositions; such environments exaggerate preexisting individual differences. PMID:25773632

Schellenberg, E Glenn

2015-03-01

60

The epigenetic lorax: gene–environment interactions in human health  

PubMed Central

Over the last decade, we have witnessed an explosion of information on genetic factors underlying common human diseases and disorders. This ‘human genomics’ information revolution has occurred as a backdrop to a rapid increase in the rates of many human disorders and diseases. For example, obesity, Type 2 diabetes, asthma, autism spectrum disorder and attention deficit hyperactivity disorder have increased at rates that cannot be due to changes in the genetic structure of the population, and are difficult to ascribe to changes in diagnostic criteria or ascertainment. A likely cause of the increased incidence of these disorders is increased exposure to environmental factors that modify gene function. Many environmental factors that have epidemiological association with common human disorders are likely to exert their effects through epigenetic alterations. This general mechanism of gene–environment interaction poses special challenges for individuals, educators, scientists and public policy makers in defining, monitoring and mitigating exposures. PMID:22920179

Latham, Keith E; Sapienza, Carmen; Engel, Nora

2012-01-01

61

Gene-environment interaction in posttraumatic stress disorder  

PubMed Central

The purpose of this article is to encourage research investigating the role of measured gene-environment interaction (G × E) in the etiology of posttraumatic stress disorder (PTSD). PTSD is uniquely suited to the study of G × E as the diagnosis requires exposure to a potentially-traumatic life event. PTSD is also moderately heritable; however, the role of genetic factors in PTSD etiology has been largely neglected both by trauma researchers and psychiatric geneticists. First, we summarize evidence for genetic influences on PTSD from family, twin, and molecular genetic studies. Second, we discuss the key challenges in G × E studies of PTSD and offer practical strategies for addressing these challenges and for discovering replicable G × E for PTSD. Finally, we propose some promising new directions for PTSD G × E research. We suggest that G × E research in PTSD is essential to understanding vulnerability and resilience following exposure to a traumatic event. PMID:18297420

Nugent, Nicole R.; Amstadter, Ananda B.

2009-01-01

62

Risk, Resilience, and Gene-Environment Interplay in Primates  

PubMed Central

Objectives: The primary objectives of the body of research reported here was to demonstrate significant interactions between genetic and social environmental factors that clearly influenced both the biological and behavioral responses of rhesus monkeys to social stressors such as separation from familial and/or familiar conspecifics throughout development and to investigate possible mechanisms underlying such interactions. Methods: Prospective longitudinal studies of rhesus monkeys reared in both captive and naturalistic settings have examined individual differences in biological and behavioral responses to stress throughout the lifespan. Results: Approximately 20% of monkeys in both settings consistently display unusually fearful and anxious-like behavioral reactions to novel, mildly stressful social situations and depressive-like symptoms following repeated separations from familial and/or familiar conspecifics during their infant and juvenile years, as well as profound and prolonged activation of the hypothalamic-pituitary-adrenal (HPA) axis in both situations. Both genetic and experiential factors – as well as their interaction -- are implicated in these reactions to social stress. For example, a specific polymorphism in the serotonin transporter gene is associated with deficits in neonatal neurobehavioral functioning and in extreme behavioral and adreno-cortical responses to social separation among infant and juvenile monkeys who experienced insecure early attachments but not in monkeys who developed secure attachment relationships with their mothers during infancy (maternal “buffering”). Similar instances of maternal “buffering” have been demonstrated in significant gene-environment interplay involving several other “candidate” gene polymorphisms. Moreover, because the attachment style of a monkey mother is typically “copied” by her daughters when they become mothers themselves, similar “buffering” is likely to occur for the next generation of infants carrying so-called “risk” alleles. Conclusions: Specific gene-environment interactions can influence behavioral and biological reactions to social stress not only throughout development but also across successive generations of rhesus monkey families. PMID:22114610

Suomi, Stephen J.

2011-01-01

63

When Chocolate Seeking Becomes Compulsion: Gene-Environment Interplay  

PubMed Central

Background Eating disorders appear to be caused by a complex interaction between environmental and genetic factors, and compulsive eating in response to adverse circumstances characterizes many eating disorders. Materials and Methods We compared compulsion-like eating in the form of conditioned suppression of palatable food-seeking in adverse situations in stressed C57BL/6J and DBA/2J mice, two well-characterized inbred strains, to determine the influence of gene-environment interplay on this behavioral phenotype. Moreover, we tested the hypothesis that low accumbal D2 receptor (R) availability is a genetic risk factor of food compulsion-like behavior and that environmental conditions that induce compulsive eating alter D2R expression in the striatum. To this end, we measured D1R and D2R expression in the striatum and D1R, D2R and ?1R levels in the medial prefrontal cortex, respectively, by western blot. Results Exposure to environmental conditions induces compulsion-like eating behavior, depending on genetic background. This behavioral pattern is linked to decreased availability of accumbal D2R. Moreover, exposure to certain environmental conditions upregulates D2R and downregulates ?1R in the striatum and medial prefrontal cortex, respectively, of compulsive animals. These findings confirm the function of gene-environment interplay in the manifestation of compulsive eating and support the hypothesis that low accumbal D2R availability is a “constitutive” genetic risk factor for compulsion-like eating behavior. Finally, D2R upregulation and ?1R downregulation in the striatum and medial prefrontal cortex, respectively, are potential neuroadaptive responses that parallel the shift from motivated to compulsive eating. PMID:25781028

Patella, Loris; Andolina, Diego; Valzania, Alessandro; Latagliata, Emanuele Claudio; Felsani, Armando; Pompili, Assunta; Gasbarri, Antonella; Puglisi-Allegra, Stefano; Ventura, Rossella

2015-01-01

64

J Epidemiol Community Health . Author manuscript Candidate gene-environment interactions  

E-print Network

a hypothesis, based on knowledge ( ).4 It can be done basically two ways ( ). The first is to study gene(sJ Epidemiol Community Health . Author manuscript Page /1 3 Candidate gene-environment interactions it corresponds to the appropriate1 concept. Gene environment interaction is a popular topic, for which there has

Paris-Sud XI, Université de

65

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

ERIC Educational Resources Information Center

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

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

2006-01-01

66

Gene-environment interaction and male reproductive function  

PubMed Central

As genetic factors can hardly explain the changes taking place during short time spans, environmental and lifestyle-related factors have been suggested as the causes of time-related deterioration of male reproductive function. However, considering the strong heterogeneity of male fecundity between and within populations, genetic variants might be important determinants of the individual susceptibility to the adverse effects of environment or lifestyle. Although the possible mechanisms of such interplay in relation to the reproductive system are largely unknown, some recent studies have indicated that specific genotypes may confer a larger risk of male reproductive disorders following certain exposures. This paper presents a critical review of animal and human evidence on how genes may modify environmental effects on male reproductive function. Some examples have been found that support this mechanism, but the number of studies is still limited. This type of interaction studies may improve our understanding of normal physiology and help us to identify the risk factors to male reproductive malfunction. We also shortly discuss other aspects of gene-environment interaction specifically associated with the issue of reproduction, namely environmental and lifestyle factors as the cause of sperm DNA damage. It remains to be investigated to what extent such genetic changes, by natural conception or through the use of assisted reproductive techniques, are transmitted to the next generation, thereby causing increased morbidity in the offspring. PMID:20348940

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

2010-01-01

67

19 Gene × Environment Interaction Models in Psychiatric Genetics  

PubMed Central

Gene-environment (G×E) interaction research is an emerging area in psychiatry, with the number of G×E studies growing rapidly in the past two decades. This article aims to give a comprehensive introduction to the field, with an emphasis on central theoretical and practical problems that are worth considering before conducting a G×E interaction study. On the theoretical side, we discuss two fundamental, but controversial questions about (1) the validity of statistical models for biological interaction and (2) the utility of G×E research for psychiatric genetics. On the practical side, we focus on study characteristics that potentially influence the outcome of G×E interaction studies and discuss strengths and pitfalls of different study designs, including recent approaches like Genome-Environment Wide Interaction Studies (GEWIS). Finally, we discuss recent developments in G×E interaction research on the most heavily investigated example in psychiatric genetics, the interaction between a serotonin transporter gene promoter variant (5-HTTLPR) and stress on depression. PMID:22241248

Karg, Katja; Sen, Srijan

2013-01-01

68

Gene-environment interactions in the etiology of human violence.  

PubMed

This chapter reviews the current research on gene-environment interactions (G × E) with regard to human violence. Findings are summarized from both behavioral and molecular genetic studies that have investigated the interplay of genetic and environmental factors in terms of influencing violence-related behavior. Together, these studies reveal promising evidence that genetic factors combine with environmental influences to impact on the development of violent behavior and related phenotypes. G × E have been identified for a number of candidate genes implicated in violence. Moreover, the reviewed G × E were found to extend to a broad range of environmental characteristics, including both adverse and favorable conditions. As has been the case with other G × E research, findings have been mixed, with considerable heterogeneity between studies. Lack of replication together with serious methodological limitations remains a major challenge for drawing definitive conclusions about the nature of violence-related G × E. In order to fulfill its potential, it is recommended that future G × E research needs to shift its focus to dissecting the neural mechanisms and the underlying pathophysiological pathways by which genetic variation may influence differential susceptibility to environmental exposures. PMID:24362945

Laucht, Manfred; Brandeis, Daniel; Zohsel, Katrin

2014-01-01

69

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

70

Electrophysiological correlates of the threshold to detection of passive motion: an investigation in professional volleyball athletes with and without atrophy of the infraspinatus muscle.  

PubMed

The goal of the present study is to compare the electrophysiological correlates of the threshold to detection of passive motion (TTDPM) among three groups: healthy individuals (control group), professional volleyball athletes with atrophy of the infraspinatus muscle on the dominant side, and athletes with no shoulder pathologies. More specifically, the study aims at assessing the effects of infraspinatus muscle atrophy on the cortical representation of the TTDPM. A proprioception testing device (PTD) was used to measure the TTDPM. The device passively moved the shoulder and participants were instructed to respond as soon as movement was detected (TTDPM) by pressing a button switch. Response latency was established as the delay between the stimulus (movement) and the response (button press). Electroencephalographic (EEG) and electromyographic (EMG) activities were recorded simultaneously. An analysis of variance (ANOVA) and subsequent post hoc tests indicated a significant difference in latency between the group of athletes without the atrophy when compared both to the group of athletes with the atrophy and to the control group. Furthermore, distinct patterns of cortical activity were observed in the three experimental groups. The results suggest that systematically trained motor abilities, as well as the atrophy of the infraspinatus muscle, change the cortical representation of the different stages of proprioceptive information processing and, ultimately, the cortical representation of the TTDPM. PMID:23484136

Salles, José Inácio; Cossich, Victor Rodrigues Amaral; Amaral, Marcus Vinicius; Monteiro, Martim T; Cagy, Maurício; Motta, Geraldo; Velasques, Bruna; Piedade, Roberto; Ribeiro, Pedro

2013-01-01

71

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

PubMed Central

The goal of the present study is to compare the electrophysiological correlates of the threshold to detection of passive motion (TTDPM) among three groups: healthy individuals (control group), professional volleyball athletes with atrophy of the infraspinatus muscle on the dominant side, and athletes with no shoulder pathologies. More specifically, the study aims at assessing the effects of infraspinatus muscle atrophy on the cortical representation of the TTDPM. A proprioception testing device (PTD) was used to measure the TTDPM. The device passively moved the shoulder and participants were instructed to respond as soon as movement was detected (TTDPM) by pressing a button switch. Response latency was established as the delay between the stimulus (movement) and the response (button press). Electroencephalographic (EEG) and electromyographic (EMG) activities were recorded simultaneously. An analysis of variance (ANOVA) and subsequent post hoc tests indicated a significant difference in latency between the group of athletes without the atrophy when compared both to the group of athletes with the atrophy and to the control group. Furthermore, distinct patterns of cortical activity were observed in the three experimental groups. The results suggest that systematically trained motor abilities, as well as the atrophy of the infraspinatus muscle, change the cortical representation of the different stages of proprioceptive information processing and, ultimately, the cortical representation of the TTDPM. PMID:23484136

Salles, José Inácio; Cossich, Victor Rodrigues Amaral; Amaral, Marcus Vinicius; Monteiro, Martim T.; Cagy, Maurício; Motta, Geraldo; Velasques, Bruna; Piedade, Roberto; Ribeiro, Pedro

2013-01-01

72

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

ERIC Educational Resources Information Center

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

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

2012-01-01

73

Passive Sonar  

NASA Astrophysics Data System (ADS)

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

Maranda, Brian H.

74

Gene-environment interactions and obesity: recent developments and future directions  

PubMed Central

Obesity, a major public health concern, is a multifactorial disease caused by both environmental and genetic factors. Although recent genome-wide association studies have identified many loci related to obesity or body mass index, the identified variants explain only a small proportion of the heritability of obesity. Better understanding of the interplay between genetic and environmental factors is the basis for developing effective personalized obesity prevention and management strategies. This article reviews recent advances in identifying gene-environment interactions related to obesity and describes epidemiological designs and newly developed statistical approaches to characterizing and discovering gene-environment interactions on obesity risk.

2015-01-01

75

Gene-environment interactions and obesity: recent developments and future directions.  

PubMed

Obesity, a major public health concern, is a multifactorial disease caused by both environmental and genetic factors. Although recent genome-wide association studies have identified many loci related to obesity or body mass index, the identified variants explain only a small proportion of the heritability of obesity. Better understanding of the interplay between genetic and environmental factors is the basis for developing effective personalized obesity prevention and management strategies. This article reviews recent advances in identifying gene-environment interactions related to obesity and describes epidemiological designs and newly developed statistical approaches to characterizing and discovering gene-environment interactions on obesity risk. PMID:25776093

Huang, Tao; Hu, Frank B

2015-12-01

76

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

77

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

78

Gene-Gene, Gene-Environment & Multiple Interactions in Colorectal Cancer  

Microsoft Academic Search

This review comprehensively evaluates the influence of gene-gene, gene-environment and multiple interactions on the risk of colorectal cancer (CRC). Methods of studying these interactions and their limitations have been discussed herein. There is a need to develop biomarkers of exposure and of risk that are sensitive, specific, present in the pathway of the disease, and that have been clinically tested

FARID E. AHMED

2006-01-01

79

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

80

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

81

Confirmatory and Competitive Evaluation of Alternative Gene-Environment Interaction Hypotheses  

ERIC Educational Resources Information Center

Background: Most gene-environment interaction (GXE) research, though based on clear, vulnerability-oriented hypotheses, is carried out using exploratory rather than hypothesis-informed statistical tests, limiting power and making formal evaluation of competing GXE propositions difficult. Method: We present and illustrate a new regression technique…

Belsky, Jay; Pluess, Michael; Widaman, Keith F.

2013-01-01

82

Gene–Environment Interactions and Susceptibility to Metabolic Syndrome and Other Chronic Diseases  

Technology Transfer Automated Retrieval System (TEKTRAN)

There is an intrinsic complexity in the pathogenesis of common diseases. The concept of gene–environment interaction is receiving support from emerging evidence coming primarily from studies involving diet and cardiovascular disease (CVD) and its various risk factors. The accumulating evidence shows...

83

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

ERIC Educational Resources Information Center

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

Kramer, Douglas A.

2005-01-01

84

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

Microsoft Academic Search

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

Sarah S. Knox

2010-01-01

85

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

ERIC Educational Resources Information Center

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…

Winham, Stacey J.; Biernacka, Joanna M.

2013-01-01

86

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

E-print Network

diseases, such as cystic fibrosis and hemophilia, are individually rare and affect approximately oneGene-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

87

Passive solar ventilation  

Microsoft Academic Search

As the twenty first Century approaches, more emphasis is given to energy conservation and passive systems in order to maintain a clean environment. New strategies showed the necessity of reviewing some design elements and their evaluation techniques. Architects should seek to increase their understanding of the correlation between the natural and the built environment.In the recent years, many architectural styles

I. F. Hamdy; M. A. Fikry

1998-01-01

88

Correlation  

NSDL National Science Digital Library

This chapter will discuss the concept of correlation , which is used in later chapters that will explain the concepts of validity and reliability. Here, the authors introduce the Pearson correlation coefficient, a statistic that is used with ratio

Edwin P. Christmann

2008-11-01

89

Passive sensors  

NASA Astrophysics Data System (ADS)

Passive sensing technologies constitute an integral and critical element of U.S. forces' antistealth-technology efforts. Multiband passive IR and electrooptic sensors can reduce the sensitivity of existing sensors to environmental and target-signature variations. A major U.S. Navy effort exists for the development of large-aperture, high-gain passive acoustic arrays capable of long-range detection of even the quietest adversary submarines. Fiber-optic sensors are under consideration for major ASW surveillance improvements and autonomous underwater-vehicle guidance. Attention is given to the development prospects for structurally embedded fiber-optic sensors and fiber-optic inertial guidance systems.

Luke, Theodore

90

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

91

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

PubMed

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

92

Behavior of QQ-Plots and Genomic Control in Studies of Gene-Environment Interaction  

Microsoft Academic Search

Genome-wide association studies of gene-environment interaction (GxE GWAS) are becoming popular. As with main effects GWAS, quantile-quantile plots (QQ-plots) and Genomic Control are being used to assess and correct for population substructure. However, in GE work these approaches can be seriously misleading, as we illustrate; QQ-plots may give strong indications of substructure when absolutely none is present. Using simulation and

Arend Voorman; Thomas Lumley; Barbara McKnight; Kenneth Rice; Stacey Cherny

2011-01-01

93

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

Cancer.gov

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

94

Gene?environment interactions in parkinsonism and Parkinson's disease: the Geoparkinson study  

PubMed Central

Objectives To investigate associations of Parkinson's disease (PD) and parkinsonian syndromes with polymorphic genes that influence metabolism of either foreign chemical substances or dopamine and to seek evidence of gene?environment interaction effects that modify risk. Methods A case?control study of 959 prevalent cases of parkinsonism (767 with PD) and 1989 controls across five European centres. Occupational hygienists estimated the average annual intensity of exposure to solvents, pesticides and metals, (iron, copper, manganese), blind to disease status. CYP2D6, PON1, GSTM1, GSTT1, GSTM3, GSTP1, NQO1, CYP1B1, MAO?A, MAO?B, SOD 2, EPHX,DAT1, DRD2 and NAT2 were genotyped. Results were analysed using multiple logistic regression adjusting for key confounders. Results There was a modest but significant association between MAO?A polymorphism in males and disease risk (G vs T, OR 1.30, 95% CI 1.02 to 1.66, adjusted). The majority of gene?environment analyses did not show significant interaction effects. There were possible interaction effects between GSTM1 null genotype and solvent exposure (which were stronger when limited to PD cases only). Conclusions Many small studies have reported associations between genetic polymorphisms and PD. Fewer have examined gene?environment interactions. This large study was sufficiently powered to examine these aspects. GSTM1 null subjects heavily exposed to solvents appear to be at increased risk of PD. There was insufficient evidence that the other gene?environment combinations investigated modified disease risk, suggesting they contribute little to the burden of PD. PMID:17449559

Dick, F D; De Palma, G; Ahmadi, A; Osborne, A; Scott, N W; Prescott, G J; Bennett, J; Semple, S; Dick, S; Mozzoni, P; Haites, N; Wettinger, S Bezzina; Mutti, A; Otelea, M; Seaton, A; Soderkvist, P; Felice, A

2007-01-01

95

Practice and public policy in the era of gene-environment interactions.  

PubMed

This chapter argues that implications of the gene-environment interaction revolution for public policy and practice are contingent on how the findings get framed in public discourse. Frame analysis is used to identify the implications of the ways in which findings are cast. The frame of 'defective group' perpetuates racial and class stereotypes and limits policy efforts to redress health disparities. Furthermore, empirical evidence finds it inaccurate. The frame of'defective gene' precludes the adaptive genetic significance of genes. The frame of 'individual genetic profile' offers individualized health care but risks misapplication in policies that place responsibility for disease prevention on the individual to the policy relief of industry and toxic environments. Framing the interaction in terms of 'defective environments' promotes the identification of harmful environments that can be regulated through policy. The 'therapeutic environment' frame offers hope of discovering interventions that have greater precision and effectiveness but risks dis-incentivizing the pharmaceutical industry from discovering drug treatments for 'obscure' gene-environment match groups. Can a more accurate and helpful framing of the gene-environment interaction be identified? Findings that genes shape environments and that environments alter the gene pool suggest a more textured and symbiotic relationship that is still in search of an apt public framing. PMID:18972747

Dodge, Kenneth A

2008-01-01

96

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

97

Passive Curvaton  

E-print Network

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

Chia-Min Lin

2013-06-19

98

A screening-testing approach for detecting gene-environment interactions using sequential penalized and unpenalized multiple logistic regression.  

PubMed

Gene-environment (G × E) interactions are biologically important for a wide range of environmental exposures and clinical outcomes. Because of the large number of potential interactions in genomewide association data, the standard approach fits one model per G × E interaction with multiple hypothesis correction (MHC) used to control the type I error rate. Although sometimes effective, using one model per candidate G × E interaction test has two important limitations: low power due to MHC and omitted variable bias. To avoid the coefficient estimation bias associated with independent models, researchers have used penalized regression methods to jointly test all main effects and interactions in a single regression model. Although penalized regression supports joint analysis of all interactions, can be used with hierarchical constraints, and offers excellent predictive performance, it cannot assess the statistical significance of G × E interactions or compute meaningful estimates of effect size. To address the challenge of low power, researchers have separately explored screening-testing, or two-stage, methods in which the set of potential G × E interactions is first filtered and then tested for interactions with MHC only applied to the tests actually performed in the second stage. Although two-stage methods are statistically valid and effective at improving power, they still test multiple separate models and so are impacted by MHC and biased coefficient estimation. To remedy the challenges of both poor power and omitted variable bias encountered with traditional G × E interaction detection methods, we propose a novel approach that combines elements of screening-testing and hierarchical penalized regression. Specifically, our proposed method uses, in the first stage, an elastic net-penalized multiple logistic regression model to jointly estimate either the marginal association filter statistic or the gene-environment correlation filter statistic for all candidate genetic markers. In the second stage, a single multiple logistic regression model is used to jointly assess marginal terms and G × E interactions for all genetic markers that pass the first stage filter. A single likelihood-ratio test is used to determine whether any of the interactions are statistically significant. We demonstrate the efficacy of our method relative to alternative G × E detection methods on a bladder cancer data set. PMID:25592580

Frost, H Robert; Andrew, Angeline S; Karagas, Margaret R; Moore, Jason H

2015-01-01

99

Enhancing the gene-environment interaction framework through a quasi-experimental research design: evidence from differential responses to September 11.  

PubMed

This article uses a gene-environment interaction framework to examine the differential responses to an objective external stressor based on genetic variation in the production of depressive symptoms. This article advances the literature by utilizing a quasi-experimental environmental exposure design, as well as a regression discontinuity design, to control for seasonal trends, which limit the potential for gene-environment correlation and allow stronger causal claims. Replications are attempted for two prominent genes (5-HTT and MAOA), and three additional genes are explored (DRD2, DRD4, and DAT1). This article provides evidence of a main effect of 9/11 on reports of feelings of sadness and fails to replicate a common finding of interaction using 5-HTT but does show support for interaction with MAOA in men. It also provides new evidence that variation in the DRD4 gene modifies an individual's response to the exposure, with individuals with no 7-repeats found to have a muted response. PMID:24784984

Fletcher, Jason M

2014-01-01

100

Gene-environment interactions in Parkinson’s disease: specific evidence in humans and mammalian models  

PubMed Central

Interactions between genetic factors and environmental exposures are thought to be major contributors to the etiology of Parkinson’s disease. While such interactions are poorly defined and incompletely understood, recent epidemiological studies have identified specific interactions of potential importance to human PD. In this review, the most current data on gene-environment interactions in PD from human studies are critically discussed. Animal models have also highlighted the importance of genetic susceptibility to toxicant exposure and data of potential relevance to human PD are discussed. Goals and needs for the future of the field are proposed. PMID:22776331

Cannon, Jason R.; Greenamyre, J. Timothy

2012-01-01

101

[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

102

Genotype-environment correlation in the era of DNA.  

PubMed

One of John Loehlin's many contributions to the field of behavioral genetics involves gene-environment (GE) correlation. The empirical base for GE correlation was research showing that environmental measures are nearly as heritable as behavioral measures and that genetic factors mediate correlations between environment and behavior. Attempts to identify genes responsible for these phenomena will come up against the 'missing heritability' problem that plagues DNA research on complex traits throughout the life sciences. However, DNA can also be used for quantitative genetic analyses of unrelated individuals (Genome-wide Complex Trait Analysis, GCTA) to investigate genetic influence on environmental measures and their behavioral correlates. A novel feature of GCTA is that it enables genetic analysis of family-level environments (e.g., parental socioeconomic status) and school-level environments (e.g., teaching quality) that cannot be investigated using within-family designs such as the twin method. An important implication of GE correlation is its shift from a passive model of the environment imposed on individuals to an active model in which individuals actively create their own experiences in part on the basis of their genetic propensities. PMID:25195166

Plomin, Robert

2014-11-01

103

Passive imaging and detection in cluttered media Josselin Garnier  

E-print Network

Passive imaging and detection in cluttered media Josselin Garnier Laboratoire de Probabilit´es et passive sensor imaging with ambient noise sources by suitably migrating the cross correlations to subsequent eruptions. Cross correlations of noisy signals recorded by a passive sensor array can also

Garnier, Josselin

104

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

PubMed Central

There are currently more than 15 million preterm births each year. We propose that gene-environment interaction is a major contributor to preterm birth. To address this experimentally, we generated a mouse model with uterine deletion of Trp53, which exhibits approximately 50% incidence of spontaneous preterm birth due to premature decidual senescence with increased mTORC1 activity and COX2 signaling. Here we provide evidence that this predisposition provoked preterm birth in 100% of females exposed to a mild inflammatory insult with LPS, revealing the high significance of gene-environment interactions in preterm birth. More intriguingly, preterm birth was rescued in LPS-treated Trp53-deficient mice when they were treated with a combination of rapamycin (mTORC1 inhibitor) and progesterone (P4), without adverse effects on maternal or fetal health. These results provide evidence for the cooperative contributions of two sites of action (decidua and ovary) toward preterm birth. Moreover, a similar signature of decidual senescence with increased mTORC1 and COX2 signaling was observed in women undergoing preterm birth. Collectively, our findings show that superimposition of inflammation on genetic predisposition results in high incidence of preterm birth and suggest that combined treatment with low doses of rapamycin and P4 may help reduce the incidence of preterm birth in high-risk women. PMID:23979163

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

2013-01-01

105

Semiparametric Bayesian analysis of case-control data under conditional gene-environment independence.  

PubMed

In case-control studies of gene-environment association with disease, when genetic and environmental exposures can be assumed to be independent in the underlying population, one may exploit the independence in order to derive more efficient estimation techniques than the traditional logistic regression analysis (Chatterjee and Carroll, 2005, Biometrika92, 399-418). However, covariates that stratify the population, such as age, ethnicity and alike, could potentially lead to nonindependence. In this article, we provide a novel semiparametric Bayesian approach to model stratification effects under the assumption of gene-environment independence in the control population. We illustrate the methods by applying them to data from a population-based case-control study on ovarian cancer conducted in Israel. A simulation study is conducted to compare our method with other popular choices. The results reflect that the semiparametric Bayesian model allows incorporation of key scientific evidence in the form of a prior and offers a flexible, robust alternative when standard parametric model assumptions do not hold. PMID:17489972

Mukherjee, Bhramar; Zhang, Li; Ghosh, Malay; Sinha, Samiran

2007-09-01

106

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

107

Correlation  

NSDL National Science Digital Library

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

Pennilyn Higgins

108

Passive Optical PassiveOpticalNetworks Contents  

E-print Network

Passive Optical Networks #12;PassiveOpticalNetworks Contents · Optical Access Networks ­ Passive Budget ­ Standards · APON/BPON · EPON · GPON · WDM-PONs ­ Proposed solutions #12;Passivex20 Mb/s TV-channels + VoD services Triple Play 10-50 Mb/s 2x5 Mb/s DVR #12;Passive

Mellia, Marco

109

Gene-environment interplay in common complex diseases: forging an integrative model—recommendations from an NIH workshop.  

PubMed

Although it is recognized that many common complex diseases are a result of multiple genetic and environmental risk factors, studies of gene-environment interaction remain a challenge and have had limited success to date. Given the current state-of-the-science, NIH sought input on ways to accelerate investigations of gene-environment interplay in health and disease by inviting experts from a variety of disciplines to give advice about the future direction of gene-environment interaction studies. Participants of the NIH Gene-Environment Interplay Workshop agreed that there is a need for continued emphasis on studies of the interplay between genetic and environmental factors in disease and that studies need to be designed around a multifaceted approach to reflect differences in diseases, exposure attributes, and pertinent stages of human development. The participants indicated that both targeted and agnostic approaches have strengths and weaknesses for evaluating main effects of genetic and environmental factors and their interactions. The unique perspectives represented at the workshop allowed the exploration of diverse study designs and analytical strategies, and conveyed the need for an interdisciplinary approach including data sharing, and data harmonization to fully explore gene-environment interactions. Further, participants also emphasized the continued need for high-quality measures of environmental exposures and new genomic technologies in ongoing and new studies. PMID:21308768

Bookman, Ebony B; McAllister, Kimberly; Gillanders, Elizabeth; Wanke, Kay; Balshaw, David; Rutter, Joni; Reedy, Jill; Shaughnessy, Daniel; Agurs-Collins, Tanya; Paltoo, Dina; Atienza, Audie; Bierut, Laura; Kraft, Peter; Fallin, M Daniele; Perera, Frederica; Turkheimer, Eric; Boardman, Jason; Marazita, Mary L; Rappaport, Stephen M; Boerwinkle, Eric; Suomi, Stephen J; Caporaso, Neil E; Hertz-Picciotto, Irva; Jacobson, Kristen C; Lowe, William L; Goldman, Lynn R; Duggal, Priya; Gunnar, Megan R; Manolio, Teri A; Green, Eric D; Olster, Deborah H; Birnbaum, Linda S

2011-05-01

110

Gene-Environment Interplay in Common Complex Diseases: Forging an Integrative Model—Recommendations From an NIH Workshop  

PubMed Central

Although it is recognized that many common complex diseases are a result of multiple genetic and environmental risk factors, studies of gene-environment interaction remain a challenge and have had limited success to date. Given the current state-of-the-science, NIH sought input on ways to accelerate investigations of gene-environment interplay in health and disease by inviting experts from a variety of disciplines to give advice about the future direction of gene-environment interaction studies. Participants of the NIH Gene-Environment Interplay Workshop agreed that there is a need for continued emphasis on studies of the interplay between genetic and environmental factors in disease and that studies need to be designed around a multifaceted approach to reflect differences in diseases, exposure attributes, and pertinent stages of human development. The participants indicated that both targeted and agnostic approaches have strengths and weaknesses for evaluating main effects of genetic and environmental factors and their interactions. The unique perspectives represented at the workshop allowed the exploration of diverse study designs and analytical strategies, and conveyed the need for an interdisciplinary approach including data sharing, and data harmonization to fully explore gene-environment interactions. Further, participants also emphasized the continued need for high-quality measures of environmental exposures and new genomic technologies in ongoing and new studies. PMID:21308768

Bookman, Ebony B.; McAllister, Kimberly; Gillanders, Elizabeth; Wanke, Kay; Balshaw, David; Rutter, Joni; Reedy, Jill; Shaughnessy, Daniel; Agurs-Collins, Tanya; Paltoo, Dina; Atienza, Audie; Bierut, Laura; Kraft, Peter; Fallin, M. Daniele; Perera, Frederica; Turkheimer, Eric; Boardman, Jason; Marazita, Mary L.; Rappaport, Stephen M.; Boerwinkle, Eric; Suomi, Stephen J.; Caporaso, Neil E.; Hertz-Picciotto, Irva; Jacobson, Kristen C.; Lowe, William L.; Goldman, Lynn R.; Duggal, Priya; Gunnar, Megan R.; Manolio, Teri A.; Green, Eric D.; Olster, Deborah H.; Birnbaum, Linda S.

2011-01-01

111

Gene-Environment Interactions, Folate Metabolism and the Embryonic Nervous System  

PubMed Central

Formation of brain and spinal cord requires the successful closure of neural ectoderm into an embryonic neural tube. Defects in this process result in anencephaly or spina bifida, which together constitute a leading cause of mortality and morbidity in children, affecting all ethnic and socioeconomic groups. The subject of intensive research for decades, neural tube defects (NTDs) are understood to arise from complex interactions of genes and environmental conditions, though systems-level details are still elusive. Despite the variety of underlying causes, a single intervention, folic acid supplementation given in the first gestational month can measurably reduce the occurrence of NTDs in a population. Evidence for and the scope of gene-environment interactions in the genesis of NTDs are discussed. A systems-based approach is now possible toward studies of genetic and environmental influences underlying NTDs that will enable the assessment of individual risk and personalized optimization of prevention. PMID:20836042

Ross, M. Elizabeth

2010-01-01

112

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

113

Externalizing Disorders and Environmental Risk: Mechanisms of Gene-Environment Interplay and Strategies for Intervention  

PubMed Central

Summary Though heritable, externalizing disorders have a number of robust associations with several environmental risk factors, including family, school, and peer contexts. To account for these associations, we integrate a behavioral genetic perspective with principles of a developmental cascade theory of antisocial behavior. The major environmental contexts associated with child externalizing problems are reviewed, as are the processes of gene-environment interplay underlying these associations. Throughout, we discuss implications for prevention and intervention. Three major approaches designed to reduce child externalizing behavior are reviewed. Prevention and intervention programs appear to be most successful when they target individuals or communities most at risk for developing externalizing disorders, rather than applied universally. We end by commenting on areas in need of additional research concerning environmental influences on persistent externalizing behaviors. PMID:25485087

Samek, Diana R.; Hicks, Brian M.

2014-01-01

114

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

115

Environmental and gene-environment interactions and risk of rheumatoid arthritis  

PubMed Central

Multiple environmental factors including hormones, dietary factors, infections and exposure to tobacco smoke as well as gene-environment interactions have been associated with increased risk for rheumatoid arthritis (RA). Importantly, the growing understanding of the prolonged period prior to the first onset of symptoms of RA suggests that these environmental and genetic factors are likely acting to drive the development of RA-related autoimmunity long before the appearance of the first joint symptoms and clinical findings that are characteristic of RA. Herein we will review these factors and interactions, especially those that have been investigated in a prospective fashion prior to the symptomatic onset of RA. We will also discuss how these factors may be explored in future study to further the understanding of the pathogenesis of RA, and ultimately perhaps develop preventive measures for this disease. PMID:22819092

Karlson, Elizabeth W.; Deane, Kevin

2012-01-01

116

Gene-gene and gene-environment interactions detected by transcriptome sequence analysis in twins.  

PubMed

Understanding the genetic architecture of gene expression is an intermediate step in understanding the genetic architecture of complex diseases. RNA sequencing technologies have improved the quantification of gene expression and allow measurement of allele-specific expression (ASE). ASE is hypothesized to result from the direct effect of cis regulatory variants, but a proper estimation of the causes of ASE has not been performed thus far. In this study, we take advantage of a sample of twins to measure the relative contributions of genetic and environmental effects to ASE, and we find substantial effects from gene × gene (G×G) and gene × environment (G×E) interactions. We propose a model where ASE requires genetic variability in cis, a difference in the sequence of both alleles, but where the magnitude of the ASE effect depends on trans genetic and environmental factors that interact with the cis genetic variants. PMID:25436857

Buil, Alfonso; Brown, Andrew Anand; Lappalainen, Tuuli; Vińuela, Ana; Davies, Matthew N; Zheng, Hou-Feng; Richards, J Brent; Glass, Daniel; Small, Kerrin S; Durbin, Richard; Spector, Timothy D; Dermitzakis, Emmanouil T

2015-01-01

117

Approaches to understanding adaptations of skin color variation by detecting gene-environment interactions.  

PubMed

Genetic and environmental factors are both part of an elaborate feedback mechanism whereby the human adaptive form reacts to environmental stimuli via internal adjustments. Human survival may ultimately depend on understanding two important components of future environmental adaptation. First, we must elucidate the dynamics of the human genome underpinning the complex human phenotype. Second, we must understand how the environment pressures and affects the genome, helping to determine human traits. This article reviews current approaches to detecting the natural selection of skin color variation in human populations. We include statistical methods for clarifying gene-environment interactions applicable to the interactions with UV radiation levels. We recommend spatial data mining as an efficient approach that applies environmental association rules, extending our knowledge of adaptation to the environment. PMID:21080816

Anno, Sumiko; Ohshima, Kazuhiko; Abe, Takashi

2010-11-01

118

Gene-environment interaction in the etiology of mathematical ability using SNP sets.  

PubMed

Mathematics ability and disability is as heritable as other cognitive abilities and disabilities, however its genetic etiology has received relatively little attention. In our recent genome-wide association study of mathematical ability in 10-year-old children, 10 SNP associations were nominated from scans of pooled DNA and validated in an individually genotyped sample. In this paper, we use a 'SNP set' composite of these 10 SNPs to investigate gene-environment (GE) interaction, examining whether the association between the 10-SNP set and mathematical ability differs as a function of ten environmental measures in the home and school in a sample of 1888 children with complete data. We found two significant GE interactions for environmental measures in the home and the school both in the direction of the diathesis-stress type of GE interaction: The 10-SNP set was more strongly associated with mathematical ability in chaotic homes and when parents are negative. PMID:20978832

Docherty, Sophia J; Kovas, Yulia; Plomin, Robert

2011-01-01

119

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

120

Two-stage testing procedures with independent filtering for genome-wide gene-environment interaction.  

PubMed

Several two-stage multiple testing procedures have been proposed to detect gene-environment interaction in genome-wide association studies. In this article, we elucidate general conditions that are required for validity and power of these procedures, and we propose extensions of two-stage procedures using the case-only estimator of gene-treatment interaction in randomized clinical trials. We develop a unified estimating equation approach to proving asymptotic independence between a filtering statistic and an interaction test statistic in a range of situations, including marginal association and interaction in a generalized linear model with a canonical link. We assess the performance of various two-stage procedures in simulations and in genetic studies from Women's Health Initiative clinical trials. PMID:23843674

Dai, James Y; Kooperberg, Charles; Leblanc, Michael; Prentice, Ross L

2012-12-01

121

MAOA, childhood maltreatment and antisocial behavior: Meta-analysis of a gene-environment interaction  

PubMed Central

Background In a seminal study of gene-environment interaction, childhood maltreatment predicted antisocial behavior more strongly in males carrying an MAOA promoter variant of lesser, compared to higher, transcriptional efficiency. Many further investigations have been reported, including studies of other early environmental exposures and females. Here we report a meta-analysis of studies testing the interaction of MAOA genotype and childhood adversities on antisocial outcomes in predominantly non-clinical samples. Method Included were 27 peer-reviewed, English-language studies published through August, 2012, that contained indicators of maltreatment or “other” family (e.g., parenting, sociodemographic) hardships; MAOA genotype; indices of aggressive and antisocial behavior; and statistical test of genotype-environment interaction. Studies of forensic and exclusively clinical samples, clinical cohorts lacking proportionally matched controls, or outcomes non-specific for antisocial behavior were excluded. The Liptak-Stouffer weighted Z-test for meta-analysis was implemented to maximize study inclusion and calculated separately for male and female cohorts. Results Across 20 male cohorts, early adversity presaged antisocial outcomes more strongly for low, relative to high, activity MAOA genotype (P=.0044). Stratified analyses showed the interaction specific to maltreatment (P=.0000008) and robust to several sensitivity analyses. Across 11 female cohorts, MAOA did not interact with combined early life adversities, whereas maltreatment alone predicted antisocial behaviors preferentially, but weakly, in females of high activity MAOA genotype (P=.02). Conclusions We found common regulatory variation in MAOA to moderate effects of childhood maltreatment on male antisocial behaviors, confirming a sentinel finding in research on gene-environment interaction. An analogous, but less consistent, finding in females warrants further investigation. PMID:23786983

Byrd, Amy L.; Manuck, Stephen B.

2013-01-01

122

Gene-environment interactions in cancer epidemiology: a National Cancer Institute Think Tank report.  

PubMed

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

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

2013-11-01

123

Lesson 58: Passive Verbs  

E-print Network

Lesson 58: Passive Verbs Passive Verbs [mnyambuliko wa vitenzi] A). Forming Passive Verbs WhenaSwahiliverbstemhasW suffixedtoit,anactiveverbbecomesa passiveone. Active Verbs Passive Verbs 1 [get] patwa [be got] #12;Sentences with Active verbs: Sentences with Passive verbs: 1. Ali

124

Gene-Environment Interaction in Externalizing Problems among Adolescents: Evidence from the Pelotas 1993 Birth Cohort Study  

ERIC Educational Resources Information Center

Background: The study of gene-environment interactions (G by 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…

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

125

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

ERIC Educational Resources Information Center

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

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

2009-01-01

126

A database of gene-environment interactions pertaining to blood lipid traits, cardiovascular disease and type 2 diabetes  

Technology Transfer Automated Retrieval System (TEKTRAN)

As the role of the environment – diet, exercise, alcohol and tobacco use and sleep among others – is accorded a more prominent role in modifying the relationship between genetic variants and clinical measures of disease, consideration of gene-environment (GxE) interactions is a must. To facilitate i...

127

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

ERIC Educational Resources Information Center

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

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

2011-01-01

128

Testing gene-environment interactions in family-based association studies using trait-based ascertained samples.  

PubMed

The study of gene-environment interactions is an increasingly important aspect of genetic epidemiological investigation. Historically, it has been difficult to study gene-environment interactions using a family-based design for quantitative traits or when parent-offspring trios were incomplete. The QBAT-I provides researchers a tool to estimate and test for a gene-environment interaction in families of arbitrary structure that are sampled without regard to the phenotype of interest, but is vulnerable to inflated type I error if families are ascertained on the basis of the phenotype. In this study, we verified the potential for type I error of the QBAT-I when applied to samples ascertained on a trait of interest. The magnitude of the inflation increases as the main genetic effect increases and as the ascertainment becomes more extreme. We propose an ascertainment-corrected score test that allows the use of the QBAT-I to test for gene-environment interactions in ascertained samples. Our results indicate that the score test and an ad hoc method we propose can often restore the nominal type I error rate, and in cases where complete restoration is not possible, dramatically reduce the inflation of the type I error rate in ascertained samples. PMID:23922213

Zhang, Weiming; Langefeld, Carl D; Grunwald, Gary K; Fingerlin, Tasha E

2014-01-30

129

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

130

BAYESIAN SEMIPARAMETRIC ANALYSIS FOR TWO-PHASE STUDIES OF GENE-ENVIRONMENT INTERACTION.  

PubMed

The two-phase sampling design is a cost-efficient way of collecting expensive covariate information on a judiciously selected sub-sample. It is natural to apply such a strategy for collecting genetic data in a sub-sample enriched for exposure to environmental factors for gene-environment interaction (G × E) analysis. In this paper, we consider two-phase studies of G × E interaction where phase I data are available on exposure, covariates and disease status. Stratified sampling is done to prioritize individuals for genotyping at phase II conditional on disease and exposure. We consider a Bayesian analysis based on the joint retrospective likelihood of phase I and phase II data. We address several important statistical issues: (i) we consider a model with multiple genes, environmental factors and their pairwise interactions. We employ a Bayesian variable selection algorithm to reduce the dimensionality of this potentially high-dimensional model; (ii) we use the assumption of gene-gene and gene-environment independence to trade-off between bias and efficiency for estimating the interaction parameters through use of hierarchical priors reflecting this assumption; (iii) we posit a flexible model for the joint distribution of the phase I categorical variables using the non-parametric Bayes construction of Dunson and Xing (2009). We carry out a small-scale simulation study to compare the proposed Bayesian method with weighted likelihood and pseudo likelihood methods that are standard choices for analyzing two-phase data. The motivating example originates from an ongoing case-control study of colorectal cancer, where the goal is to explore the interaction between the use of statins (a drug used for lowering lipid levels) and 294 genetic markers in the lipid metabolism/cholesterol synthesis pathway. The sub-sample of cases and controls on which these genetic markers were measured is enriched in terms of statin users. The example and simulation results illustrate that the proposed Bayesian approach has a number of advantages for characterizing joint effects of genotype and exposure over existing alternatives and makes efficient use of all available data in both phases. PMID:24587840

Ahn, Jaeil; Mukherjee, Bhramar; Gruber, Stephen B; Ghosh, Malay

2013-03-01

131

Gene?×?Environment Interactions in Autism Spectrum Disorders: Role of Epigenetic Mechanisms  

PubMed Central

Several studies support currently the hypothesis that autism etiology is based on a polygenic and epistatic model. However, despite advances in epidemiological, molecular and clinical genetics, the genetic risk factors remain difficult to identify, with the exception of a few chromosomal disorders and several single gene disorders associated with an increased risk for autism. Furthermore, several studies suggest a role of environmental factors in autism spectrum disorders (ASD). First, arguments for a genetic contribution to autism, based on updated family and twin studies, are examined. Second, a review of possible prenatal, perinatal, and postnatal environmental risk factors for ASD are presented. Then, the hypotheses are discussed concerning the underlying mechanisms related to a role of environmental factors in the development of ASD in association with genetic factors. In particular, epigenetics as a candidate biological mechanism for gene?×?environment interactions is considered and the possible role of epigenetic mechanisms reported in genetic disorders associated with ASD is discussed. Furthermore, the example of in utero exposure to valproate provides a good illustration of epigenetic mechanisms involved in ASD and innovative therapeutic strategies. Epigenetic remodeling by environmental factors opens new perspectives for a better understanding, prevention, and early therapeutic intervention of ASD. PMID:25136320

Tordjman, Sylvie; Somogyi, Eszter; Coulon, Nathalie; Kermarrec, Solenn; Cohen, David; Bronsard, Guillaume; Bonnot, Olivier; Weismann-Arcache, Catherine; Botbol, Michel; Lauth, Bertrand; Ginchat, Vincent; Roubertoux, Pierre; Barburoth, Marianne; Kovess, Viviane; Geoffray, Marie-Maude; Xavier, Jean

2014-01-01

132

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

133

Gene-Environment Interplay in the Association between Pubertal Timing and Delinquency in Adolescent Girls  

PubMed Central

Early pubertal timing places girls at elevated risk for a breadth of negative outcomes, including involvement in delinquent behavior. While previous developmental research has emphasized the unique social challenges faced by early maturing girls, this relation is complicated by genetic influences for both delinquent behavior and pubertal timing, which are seldom controlled for in existing research. The current study uses genetically informed data on 924 female-female twin and sibling pairs drawn from the National Longitudinal Study of Adolescent Health to (1) disentangle biological versus environmental mechanisms for the effects of early pubertal timing and (2) test for gene-environment interactions. Results indicate that early pubertal timing influences girls’ delinquency through a complex interplay between biological risk and environmental experiences. Genes related to earlier age at menarche and higher perceived development significantly predict increased involvement in both non-violent and violent delinquency. Moreover, after accounting for this genetic association between pubertal timing and delinquency, the impact of non-shared environmental influences on delinquency are significantly moderated by pubertal timing, such that the non-shared environment is most important among early maturing girls. This interaction effect is particularly evident for non-violent delinquency. Overall, results suggest early maturing girls are vulnerable to an interaction between genetic and environmental risks for delinquent behavior. PMID:21668078

Harden, K. Paige; Mendle, Jane

2014-01-01

134

What gene-environment interactions can tell us about social competence in typical and atypical populations.  

PubMed

Social competence is a complex human behaviour that is likely to involve a system of genes that interacts with a myriad of environmental risk and protective factors. The search for its genetic and environmental origins and influences is equally complex and will require a multidimensional conceptualization and multiple methods and levels of analysis. Behavioural genetic research can begin to address the fundamental yet complex question of how children develop social competence by uncovering the various influences on social development and disentangling variance due to multiple genes, environments and experiences. In this paper, we review the current status of research on sociability, face recognition, emotion recognition, and theory of mind (TOM)--well defined and measured constructs that are likely to be useful indices for detecting genetic and environmental influences on social competence. We also propose specific milestones as indices of further progress in the field: the development of an operational definition of the construct of social competence, the identification of social endophenotypes-psychological processes that are validly and reliably measured components of social competence, and improving specificity and homogeneity with regard to social endophenotypes within a population of study by employing 'extreme social phenotypes'. These efforts will lead to a better understanding of the specific contributions to the normal variation of social competence in the general population as well as to atypical social development. PMID:17628271

Iarocci, Grace; Yager, Jodi; Elfers, Theo

2007-10-01

135

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

PubMed Central

While genetic factors account for a significant proportion of liability to schizophrenia, a body of evidence attests to a significant environmental contribution. Understanding the mechanisms through which genetic and environmental factors coalesce in influencing schizophrenia is critical for elucidating the pathways underlying psychotic illness and for developing primary prevention strategies. Although obstetric complications (OCs) remain among the most well-documented environmental indicators of risk for schizophrenia, the pathogenic role they play in the etiology of schizophrenia continues to remain poorly understood. A question of major importance is do these factors result from a genetic diathesis to schizophrenia (as in gene-environment covariation), act additively or interactively with predisposing genes for the disorder in influencing disease risk, or independently cause disease onset? In this review, we evaluate 3 classes of OCs commonly related to schizophrenia including hypoxia-associated OCs, maternal infection during pregnancy, and maternal stress during pregnancy. In addition, we discuss several mechanisms by which OCs impact on genetically susceptible brain regions, increasing constitutional vulnerability to neuromaturational events and stressors later in life (ie, adolescence), which may in turn contribute to triggering psychosis. PMID:18635675

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

2008-01-01

136

The role of linkage disequilibrium in case-only studies of gene-environment interactions.  

PubMed

Gene-environment (G × E) interactions have been invoked to account, at least in part, for the gap between the known heritability of common human diseases and the phenotypic variation hitherto explained by genetic variants. Noteworthy in this context, a case-only (CO) design has been proposed in the past as a means to detect G × E interactions possibly more efficiently than by using classical case-control and cohort designs. So far, however, most CO studies have followed a candidate (or single) gene approach, and the genome-wide utility of the CO design is still more or less unknown. In particular, the way in which linkage disequilibrium (LD) impacts upon the chance to detect G × E interaction through the analysis of proxy markers has not been studied in much detail before. Therefore, we systematically assessed the power to indirectly detect a given G × E interaction through exploiting LD in a CO design. Our simulations revealed a strong relationship between LD and detection power that was subsequently validated in a real colorectal cancer data set. PMID:25304818

Yadav, Pankaj; Freitag-Wolf, Sandra; Lieb, Wolfgang; Krawczak, Michael

2015-01-01

137

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

138

FKBP5 and resistant attachment predict cortisol reactivity in infants: gene-environment interaction.  

PubMed

Quality of the parent-infant attachment relationship influences physiological stress regulation. Genetic factors also contribute to the stress regulatory HPA-axis. Quality of attachment as an index of the rearing environment (measured with the Strange Situation Procedure, SSP), and HPA-axis related SNPs (BclI, rs41423247; TthIIII, rs10052957; GR-9?, rs6198; N363S, rs6195; ER22/23EK, rs6189 and 6190; and FKBP5, rs1360780) were hypothesized to be related to cortisol reactivity in the stressful SSP. In this large population based sample, FKBP5 rs1360780, but not GR haplotype, was related to cortisol reactivity. Moreover, we found a significant interaction effect for insecure-resistant attachment and FKBP5 rs1360780, indicating a double-risk for heightened cortisol reactivity levels in infants with one or two T-alleles of the FKBP5 SNP and an insecure-resistant attachment relationship with their mother. Findings are discussed from the perspective of gene-environment interaction. PMID:20547006

Luijk, Maartje P C M; Velders, Fleur P; Tharner, Anne; van Ijzendoorn, Marinus H; Bakermans-Kranenburg, Marian J; Jaddoe, Vincent W V; Hofman, Albert; Verhulst, Frank C; Tiemeier, Henning

2010-11-01

139

Gene-environment interactions at the FKBP5 locus: sensitive periods, mechanisms and pleiotropism.  

PubMed

Psychiatric phenotypes are multifactorial and polygenic, resulting from the complex interplay of genes and environmental factors that act cumulatively throughout an organism's lifetime. Adverse life events are strong predictors of risk for a number of psychiatric disorders and a number of studies have focused on gene-environment interactions (GxEs) occurring at genetic loci involved in the stress response. Such a locus that has received increasing attention is the gene encoding FK506 binding protein 51 (FKBP5), a heat shock protein 90 cochaperone of the steroid receptor complex that among other functions regulates sensitivity of the glucocorticoid receptor. Interactions between FKBP5 gene variants and life stressors alter the risk not only for mood and anxiety disorders, but also for a number of other disease phenotypes. In this review, we will focus on molecular and system-wide mechanisms of this GxE with the aim of establishing a framework that explains GxE interactions. We will also discuss how an understanding of the biological effects of this GxE may lead to novel therapeutic approaches. PMID:24219237

Zannas, A S; Binder, E B

2014-01-01

140

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

PubMed Central

Rationale Prior reviews have examined how stress, broadly defined, interacts with genetic diathesis in the pathogenesis of internalizing (i.e., depressive and anxiety) disorders. Recent findings have suggested a unique role for early life stress (ELS) in the development of internalizing disorders, contributing to the rapid proliferation of research in this area. Objective This paper critically reviews studies in humans examining gene–environment interaction (GxE) effects of ELS on the risk for depression and anxiety, primarily from a candidate gene perspective. Major methodological challenges that are unique to such studies are considered. Results The majority of published studies have focused on candidates that regulate the serotonin system, especially the serotonin transporter. More recent work has addressed interactions of ELS with candidates from the hypothalamic-pituitary-adrenal axis and neurotrophin system. Available studies vary greatly with respect to definitions of ELS, examination of gene–gene interactions, consideration of gender effects, and attention to analytic limitations. Conclusions Overall, there is support for GxE effects of ELS on the risk for depressive and anxiety outcomes. Future studies of ELS in this context will require careful attention to methodologic considerations. Such studies would benefit from more systematic assessment of positive environmental factors (e.g., social support) and greater utilization of developmentally sensitive paradigms. PMID:21225419

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

2013-01-01

141

Bayesian variable selection for hierarchical gene-environment and gene-gene interactions.  

PubMed

We propose a Bayesian hierarchical mixture model framework that allows us to investigate the genetic and environmental effects, gene by gene interactions and gene by environment interactions in the same model. Our approach incorporates the natural hierarchical structure between the main effects and interaction effects into a mixture model, such that our methods tend to remove the irrelevant interaction effects more effectively, resulting in more robust and parsimonious models. We consider both strong and weak hierarchical models. For a strong hierarchical model, both the main effects between interacting factors must be present for the interactions to be considered in the model development, while for a weak hierarchical model, only one of the two main effects is required to be present for the interaction to be evaluated. Our simulation results show that the proposed strong and weak hierarchical mixture models work well in controlling false-positive rates and provide a powerful approach for identifying the predisposing effects and interactions in gene-environment interaction studies, in comparison with the naive model that does not impose this hierarchical constraint in most of the scenarios simulated. We illustrate our approach using data for lung cancer and cutaneous melanoma. PMID:25154630

Liu, Changlu; Ma, Jianzhong; Amos, Christopher I

2015-01-01

142

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

143

Comparison between whitened generalized cross correlation and adaptive filter for time delay estimation with scattered arrays for passive positioning of moving targets in Baltic Sea shallow waters  

Microsoft Academic Search

Results from an acoustic measurement campaign in shallow waters (at 22 meters depth) are given. Eight hydrophones, placed at the seabed, were used simultaneously to investigate how different distances between hydrophones affect the Time Delay Estimation (IDE). In order to position targets two TDE methods were applied. The used methods were the Generalized Cross Correlation (GCQ function weighted by the

V. Zetterberg; M. I. Pettersson; I. Claesson

2005-01-01

144

Effects of exposure to amphetamine derivatives on passive avoidance performance and the central levels of monoamines and their metabolites in mice: correlations between behavior and neurochemistry  

PubMed Central

Rationale Considerable evidence indicates that amphetamine derivatives can deplete brain monoaminergic neurotransmitters. However, the behavioral and cognitive consequences of neurochemical depletions induced by amphetamines are not well established. Objectives In this study, mice were exposed to dosing regimens of 3,4-methylenedioxymethamphetamine (MDMA), methamphetamine (METH), or para-chloroamphetamine (PCA) known to deplete the monoamine neurotransmitters dopamine and serotonin, and the effects of these dosing regimens on learning and memory were assessed. Methods In the same animals, we determined deficits in learning and memory via passive avoidance (PA) behavior and changes in tissue content of monoamine neurotransmitters and their primary metabolites in the striatum, frontal cortex, cingulate, hippocampus, and amygdala via ex vivo high pressure liquid chromatography. Results Consistent with previous studies, significant reductions in tissue content of dopamine and serotonin were readily apparent. In addition, exposure to METH and PCA impaired PA performance and resulted in significant depletions of dopamine, serotonin, and their metabolites in several brain regions. Multiple linear regression analysis revealed that the tissue concentration of dopamine in the anterior striatum was the strongest predictor of PA performance, with an additional significant contribution by the tissue concentration of the serotonin metabolite 5-hydroxyindoleacetic acid in the cingulate. In contrast to the effects of METH and PCA, exposure to MDMA did not deplete anterior striatal dopamine levels or cingulate levels of 5-hydroxyindoleacetic acid, and it did not impair PA performance. Conclusions These studies demonstrate that certain amphetamines impair PA performance in mice and that these impairments may be attributable to specific neurochemical depletions. PMID:21993877

Murnane, Kevin Sean; Perrine, Shane Alan; Finton, Brendan James; Galloway, Matthew Peter; Howell, Leonard Lee; Fantegrossi, William Edward

2011-01-01

145

Passive solar technology  

SciTech Connect

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

Watson, D

1981-04-01

146

2D Raman correlation analysis of formation mechanism of passivating film on overcharged LiCoO2 electrode with additive system  

NASA Astrophysics Data System (ADS)

The effect of vinylene carbonate (VC) as solid electrolyte interface (SEI)-forming additive on the electrochemical performance of the LiCoO2 cathode was investigated by galvanostatic charge-discharge testing as well as Raman and 2D correlation spectroscopy. It was found that VC-containing electrolyte has a positive effect on capacity fading. An analysis of the 2D Raman correlation spectra suggested that even though the same SEI components (i.e., Co3O4 and Li2O) are produced on the cathode surface, the electrochemical reaction kinetics in the cathode/electrolyte interface differ according to the non-use or use of VC: in the latter case, formation of the SEI components is delayed.

Park, Yeonju; Shin, Su Hyun; Lee, Sung Man; Kim, Sung Phil; Choi, Hyun Chul; Jung, Young Mee

2014-07-01

147

Passive Acoustic Vessel Localization  

NASA Astrophysics Data System (ADS)

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

Suwal, Pasang Sherpa

148

Latitudinal Body Size Clines in the Butterfly Polyommatus icarus are Shaped by Gene-Environment Interactions  

PubMed Central

The study of latitudinal body size clines can illuminate processes of local adaptation, but there is a need for an increased understanding of the relative roles of genetic variation, environmental effectstions or this reason, we combined an investigation of a museum collection of the common blue butterfly Polyommatus icarus (Rottemburg) (Lycaenidae: Polyommatini) from Sweden with a common-garden experiment in the laboratory, using strains reared from individuals collected from three different latitudes. Sizes of the field-collected butterflies tended to smoothly decrease northwards in a latitudinal cline, but suddenly increase at the latitude where the life cycle changes from two to one generations per year, hence allowing more time for this single generation. Further north, the size of the field-collected butterflies again decreased with latitude (with the exception of the northernmost collection sites). This is in accordance with the “converse Bergmann” pattern and with the “saw-tooth model” suggesting that insect size is shaped by season length and number of generations along latitudinal transects. In contrast, under laboratory conditions with a constant long day-length there was a different pattern, with the butterflies pupating at a higher mass when individuals originated from southern populations under time stress to achieve a second generation. This is indirect evidence for field patterns being shaped by end-of-season cues cutting development short, and also suggests counter-gradient variation, as butterflies from the time-stressed populations over-compensated for decreasing larval development time by increasing their growth rates, thus obtaining higher mass. Hence, we found support for both adaptive phenotypic plasticity and local genetic adaptation, with gene-environment interactions explaining the observed field patterns.

Nygren, Georg H.; Bergström, Anders; Nylin, Sören

2008-01-01

149

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

PubMed Central

Study Objectives: To examine whether sleep duration modifies genetic and environmental influences on body mass index (BMI). Design: Genotype-environment interaction twin study. Setting: University of Washington Twin Registry. Patients or Participants: A population-based sample of US twins (1,088 pairs, 604 monozygotic, 484 dizygotic; 66% female; mean age = 36.6 yr, standard deviation (SD) = 15.9 yr). Interventions: N/A. Measurements and Results: Participants self-reported information on height, weight, and sleep. Mean BMI was calculated as 25.3 kg/m2 (SD = 5.4) and mean habitual sleep duration was 7.2 hr/night (SD = 1.2). Data were analyzed using biometric genetic interaction models. Overall the heritability of sleep duration was 34%. Longer sleep duration was associated with decreased BMI (P < 0.05). The heritability of BMI when sleep duration was < 7 hr (h2 = 70%) was more than twice as large as the heritability of BMI when sleep duration was ? 9 hr (h2 = 32%); this interaction was significant (P < 0.05). Conclusions: Shorter sleep duration is associated with increased BMI and increased genetic influences on BMI, suggesting that shorter sleep duration increases expression of genetic risks for high body weight. At the same time, longer sleep duration may suppress genetic influences on body weight. Future research aiming to identify specific genotypes for BMI may benefit by considering the moderating role of sleep duration. Citation: Watson NF; Harden KP; Buchwald D; Vitiello MV; Pack AI; Weigle DS; Goldberg J. Sleep duration and body mass index in twins: a gene-environment interaction. SLEEP 2012;35(5):597-603. PMID:22547885

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

2012-01-01

150

Evidence for gene-environment interaction in a genome wide study of nonsyndromic cleft palate.  

PubMed

Nonsyndromic cleft palate (CP) is a common birth defect with a complex and heterogeneous etiology involving both genetic and environmental risk factors. We conducted a genome-wide association study (GWAS) using 550 case-parent trios, ascertained through a CP case collected in an international consortium. Family-based association tests of single nucleotide polymorphisms (SNP) and three common maternal exposures (maternal smoking, alcohol consumption, and multivitamin supplementation) were used in a combined 2 df test for gene (G) and gene-environment (G × E) interaction simultaneously, plus a separate 1 df test for G × E interaction alone. Conditional logistic regression models were used to estimate effects on risk to exposed and unexposed children. While no SNP achieved genome-wide significance when considered alone, markers in several genes attained or approached genome-wide significance when G × E interaction was included. Among these, MLLT3 and SMC2 on chromosome 9 showed multiple SNPs resulting in an increased risk if the mother consumed alcohol during the peri-conceptual period (3 months prior to conception through the first trimester). TBK1 on chr. 12 and ZNF236 on chr. 18 showed multiple SNPs associated with higher risk of CP in the presence of maternal smoking. Additional evidence of reduced risk due to G × E interaction in the presence of multivitamin supplementation was observed for SNPs in BAALC on chr. 8. These results emphasize the need to consider G × E interaction when searching for genes influencing risk to complex and heterogeneous disorders, such as nonsyndromic CP. PMID:21618603

Beaty, Terri H; Ruczinski, Ingo; Murray, Jeffrey C; Marazita, Mary L; Munger, Ronald G; Hetmanski, Jacqueline B; Murray, Tanda; Redett, Richard J; Fallin, M Daniele; Liang, Kung Yee; Wu, Tao; Patel, Poorav J; Jin, Sheng-Chih; Zhang, Tian Xiao; Schwender, Holger; Wu-Chou, Yah Huei; Chen, Philip K; Chong, Samuel S; Cheah, Felicia; Yeow, Vincent; Ye, Xiaoqian; Wang, Hong; Huang, Shangzhi; Jabs, Ethylin W; Shi, Bing; Wilcox, Allen J; Lie, Rolv T; Jee, Sun Ha; Christensen, Kaare; Doheny, Kimberley F; Pugh, Elizabeth W; Ling, Hua; Scott, Alan F

2011-09-01

151

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, Núria; Arias Perez, JoséI.; Benítez, Javier; Flyger, Henrik; Nordestgaard, Břrge G.; Truong, Théresč; Cordina-Duverger, Emilie; Menegaux, Florence; Silva, Isabel dos Santos; Fletcher, Olivia; Johnson, Nichola; Häberle, 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; Guénel, 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

152

G x E: a NIAAA workshop on gene-environment interactions.  

PubMed

The National Institute on Alcohol Abuse and Alcoholism (NIAAA) sponsored a May 2002 workshop on gene-environment interaction (G x E) research to identify potential roadblocks to further research and to propose solutions to those roadblocks, to optimize investigative opportunities and multidisciplinary or multi-institution collaborations, and to explore ways that NIAAA can facilitate G x E studies. Sessions included panels on animal models; phenotypes; genetic findings in humans; study designs and analytical methods; and assessment of environmental risk. Key among the identified challenges to progress in G x E research were issues of study design and sampling strategies; logistic and methodological costs and constraints; availability and understanding of data analysis techniques; potential stigmatization of study populations; and organizational/bureaucratic structures that are inadequate to address the unique needs of large-scale, multicenter, longitudinal projects. Participants proposed a series of recommendations to address these issues. Session coordinators included: Gayle Boyd, Kendall Bryant, Page Chiapella, Vivian Faden, David Goldman, and Antonio Noronha. Session participants included: Laura Almasy, Henri Begleiter, Raul Caetano, Bruce Dudek, Mary Dufour, Cindy Ehlers, Mary-Anne Enoch, Joel Gelernter, David Goldman, Bridget Grant, Lorraine Gunzerath, Deborah Hasin, Andrew Heath, Victor Hesselbrock, J. Dee Higley, Shirley Hill, Kerry Jang, Raynard S. Kington, Rick Kittles, George Koob, Kenneth Leonard, Ting-Kai Li, Jeffrey Long, William McBride, Matthew McGue, Kathleen Merikangas, Tamara Phillips, Bernice Porjesz, Carol Prescott, Theodore Reich, John Rice, Richard Rose, Charmaine Royal, Arnold Sameroff, Marc Schuckit, Kenneth Sher, Renee Sieving, Robert Taylor, Michael Windle, and Robert Zucker. PMID:12658122

Gunzerath, Lorraine; Goldman, David

2003-03-01

153

Principal Interactions Analysis for Repeated Measures Data: Application to Gene-Gene, Gene-Environment Interactions  

PubMed Central

Many existing cohorts with longitudinal data on environmental exposures, occupational history, lifestyle/behavioral characteristics and health outcomes have collected genetic data in recent years. In this paper, we consider the problem of modeling gene-gene, gene-environment interactions with repeated measures data on a quantitative trait. We review possibilities of using classical models proposed by Tukey (1949) and Mandel (1961) using the cell means of a two-way classification array for such data. Whereas these models are effective for detecting interactions in presence of main effects, they fail miserably if the interaction structure is misspecified. We explore a more robust class of interaction models that are based on a singular value decomposition of the cell means residual matrix after fitting the additive main effect terms. This class of additive main effects and multiplicative interaction (AMMI) models (Gollob, 1968) provide useful summaries for subject-specific and time-varying effects as represented in terms of their contribution to the leading eigenvalues of the interaction matrix. It also makes the interaction structure more amenable to geometric representation. We call this analysis “Principal Interactions Analysis” (PIA). While the paper primarily focusses on a cell-mean based analysis of repeated measures outcome, we also introduce resampling-based methods that appropriately recognize the unbalanced and longitudinal nature of the data instead of reducing the response to cell-means. The proposed methods are illustrated by using data from the Normative Aging Study, a longitudinal cohort study of Boston area veterans since 1963. We carry out simulation studies under an array of classical interaction models and common epistasis models to illustrate the properties of the PIA procedure in comparison to the classical alternatives. PMID:22415818

Mukherjee, Bhramar; Ko, Yi-An; Vanderweele, Tyler; Roy, Anindya; Park, Sung Kyun; Chen, Jinbo

2012-01-01

154

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

155

Passive solar design handbook. Volume III. Passive solar design analysis  

SciTech Connect

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. (LEW)

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

1982-07-01

156

Gene-environment interplay in alcoholism and other substance abuse disorders: Expressions of heritability and factors influencing vulnerabilities  

Microsoft Academic Search

Factors that confer predisposition and vulnerability for alcoholism and other substance abuse disorders may be described usefully\\u000a within the gene-environment interplay framework. Thus, it is postulated that heritability provides a major contribution not\\u000a only to alcohol but also to other substances of abuse. Studies of evoked potential amplitude reduction have provided a highly\\u000a suitable and testable method for the assessment

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

2004-01-01

157

Fundamental studies of passivity and passivity breakdown  

SciTech Connect

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

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

1991-11-01

158

Perinatal Gene-Gene and Gene-Environment Interactions on IgE Production and Asthma Development  

PubMed Central

Atopic asthma is a complex disease associated with IgE-mediated immune reactions. Numerous genome-wide studies identified more than 100 genes in 22 chromosomes associated with atopic asthma, and different genetic backgrounds in different environments could modulate susceptibility to atopic asthma. Current knowledge emphasizes the effect of tobacco smoke on the development of childhood asthma. This suggests that asthma, although heritable, is significantly affected by gene-gene and gene-environment interactions. Evidence has recently shown that molecular mechanism of a complex disease may be limited to not only DNA sequence differences, but also gene-environmental interactions for epigenetic difference. This paper reviews and summarizes how gene-gene and gene-environment interactions affect IgE production and the development of atopic asthma in prenatal and childhood stages. Based on the mechanisms responsible for perinatal gene-environment interactions on IgE production and development of asthma, we formulate several potential strategies to prevent the development of asthma in the perinatal stage. PMID:22481967

Chang, Jen-Chieh; Wang, Lin; Chen, Rong-Fu; Liu, Chieh-An

2012-01-01

159

Dynamics of Passive Scalars and Probe Particles in Driven  

E-print Network

Dynamics of Passive Scalars and Probe Particles in Driven Diffusive Systems Sakuntala Chatterjee . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Probe Particles in a Driven Diffusive Medium . . . . . . . . . . . 9 2 Dynamics of Passive-correlation Function in Steady State . . . . . . . . . 23 2.3.2 Space-time Correlation Function in Steady State

160

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

PubMed Central

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 population. However, a general methodology to analyze twin data is required because of the potential importance of gene-gene interactions (epistasis), gene-environment interactions, and conditions that break the 'equal environments' assumption for monozygotic and dizygotic twins. Method A new model for gene-gene and gene-environment interactions is developed that abandons the assumptions of the classical twin study, including Fisher's (1918) assumption that genes act as risk factors for common traits in a manner necessarily dominated by an additive polygenic term. Provided there are no confounders, the model can be used to implement a top-down approach to quantifying the potential utility of genetic prediction and prevention, using twin, family and environmental data. The results describe a solution space for each disease or trait, which may or may not include the classical twin study result. Each point in the solution space corresponds to a different model of genotypic risk and gene-environment interaction. Conclusion The results show that the potential for reducing the incidence of common diseases using environmental interventions targeted by genotype may be limited, except in special cases. The model also confirms that the importance of an individual's genotype in determining their risk of complex diseases tends to be exaggerated by the classical twin studies method, owing to the 'equal environments' assumption and the assumption of no gene-environment interaction. In addition, if phenotypes are genetically robust, because of epistasis, a largely environmental explanation for shared sibling risk is plausible, even if the classical heritability is high. The results therefore highlight the possibility – previously rejected on the basis of twin study results – that inherited genetic variants are important in determining risk only for the relatively rare familial forms of diseases such as breast cancer. If so, genetic models of familial aggregation may be incorrect and the hunt for additional susceptibility genes could be largely fruitless. PMID:17029623

Wallace, Helen M

2006-01-01

161

Toward a 3D model of human brain development for studying gene/environment interactions  

PubMed Central

This project aims to establish and characterize an in vitro model of the developing human brain for the purpose of testing drugs and chemicals. To accurately assess risk, a model needs to recapitulate the complex interactions between different types of glial cells and neurons in a three-dimensional platform. Moreover, human cells are preferred over cells from rodents to eliminate cross-species differences in sensitivity to chemicals. Previously, we established conditions to culture rat primary cells as three-dimensional aggregates, which will be humanized and evaluated here with induced pluripotent stem cells (iPSCs). The use of iPSCs allows us to address gene/environment interactions as well as the potential of chemicals to interfere with epigenetic mechanisms. Additionally, iPSCs afford us the opportunity to study the effect of chemicals during very early stages of brain development. It is well recognized that assays for testing toxicity in the developing brain must consider differences in sensitivity and susceptibility that arise depending on the time of exposure. This model will reflect critical developmental processes such as proliferation, differentiation, lineage specification, migration, axonal growth, dendritic arborization and synaptogenesis, which will probably display differences in sensitivity to different types of chemicals. Functional endpoints will evaluate the complex cell-to-cell interactions that are affected in neurodevelopment through chemical perturbation, and the efficacy of drug intervention to prevent or reverse phenotypes. The model described is designed to assess developmental neurotoxicity effects on unique processes occurring during human brain development by leveraging human iPSCs from diverse genetic backgrounds, which can be differentiated into different cell types of the central nervous system. Our goal is to demonstrate the feasibility of the personalized model using iPSCs derived from individuals with neurodevelopmental disorders caused by known mutations and chromosomal aberrations. Notably, such a human brain model will be a versatile tool for more complex testing platforms and strategies as well as research into central nervous system physiology and pathology. PMID:24564953

2013-01-01

162

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

163

Immunizations: Active vs. Passive  

MedlinePLUS

... they’ve been exposed. For example, the passive rabies immunization (rabies immune globulin) is commonly used after a certain type of wild animal bites a child. Passive immunizations for hepatitis A (gamma globulin) may be helpful ...

164

Passive solar workbook  

SciTech Connect

After a case is presented for the use of solar energy, principles of solar kinetics, solar radiation and weather, and heat flow are reviewed and active, passive and hybrid systems are briefly discussed. Site planning, orientation, and landscaping and solar access are covered, as are the design and components of passive solar systems. Calculation methods are presented for determining building heating load profile, auxiliary load profile, and thermal storage capacity. Construction details are given for foundation, wall, and storage insulation, Trombe walls, movable insulation, and shading devices. Passive solar cooling is also covered. Interior applications for passive solar design are discussed and financial considerations are presented. (LEW)

Not Available

1981-08-01

165

New passive helicopter detector  

SciTech Connect

Sandia has developed a new helicopter detector. The device relies on the correlation between the acoustic wave from the helicopter and the resulting coupled seismic wave. A significant feature of this approach is that the detector is completely passive; there is no radio frequency radiation. Intended for deployment as a perimeter sensor around a site, the unit offers a low nuisance/false alarm rate and a high probability of detection for a wide range of helicopters. Reliable detection occurs when the target is at high altitude and also very near the earth's surface. Detection ranges start at one kilometer for the small, four-place, civilian helicopter and approach five kilometers for heavier, military types. The system has two parts: a transducer package containing a microphone and a geophone and a digital processor. Development is underway for a model which will be AC powered and well suited to permanent facilities. A prototype unit using a lightweight, battery powered processor is being constructed for rapid-deployment applications. 6 figs.

Elliott, G.R.

1985-01-01

166

Physics of passive solar buildings  

SciTech Connect

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

Balcomb, J.D.

1981-01-01

167

Passive Solar Design  

NSDL National Science Digital Library

Students are introduced to passive solar design for buildings — an approach that uses the sun's energy and the surrounding climate to provide natural heating and cooling. They learn about some of the disadvantages of conventional heating and cooling and how engineers incorporate passive solar designs into our buildings for improved efficiency.

2014-09-18

168

Coordinated passivation designs  

Microsoft Academic Search

In two-input (or multi-input) nonlinear systems it may be possible to achieve feedback passivation of a chosen input using the second input (other inputs) to improve the stability properties of the 5rst input's zero dynamics. This 'coordinated passivation' approach is illustratedon a simpli5edmod el of a turbochargedd iesel engine. ? 2002 Elsevier Science Ltd. All rights reserved.

Michael Larsen; Mrdjan Jankovic; Petar V. Kokotovic

2003-01-01

169

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

170

Passive Cryogenic Sampler  

NASA Astrophysics Data System (ADS)

Sampling is the key step in any analysis regime. Gaseous systems only magnify the critical nature of the sampling step. The Passive Cryogenic Gas Sampler provides a proven, cost-effective way to obtain high-quality samples. This report specifies some advantages and design specifications of the Passive Cryogenic Gas Sampler.

171

Passive solar building design  

SciTech Connect

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

Carter, C.; De Villiers, J.

1987-01-01

172

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

173

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

174

Inclusion of Gene-Gene and Gene-Environment Interactions Unlikely to Dramatically Improve Risk Prediction for Complex Diseases  

PubMed Central

Genome-wide association studies have identified hundreds of common genetic variants associated with the risk of multifactorial diseases. However, their impact on discrimination and risk prediction is limited. It has been suggested that the identification of gene-gene (G-G) and gene-environment (G-E) interactions would improve disease prediction and facilitate prevention. We conducted a simulation study to explore the potential improvement in discrimination if G-G and G-E interactions exist and are known. We used three diseases (breast cancer, type 2 diabetes, and rheumatoid arthritis) as motivating examples. We show that the inclusion of G-G and G-E interaction effects in risk-prediction models is unlikely to dramatically improve the discrimination ability of these models. PMID:22633398

Aschard, Hugues; Chen, Jinbo; Cornelis, Marilyn C.; Chibnik, Lori B.; Karlson, Elizabeth W.; Kraft, Peter

2012-01-01

175

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

PubMed

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

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

2013-10-01

176

A powerful statistical method identifies novel loci associated with diastolic blood pressure triggered by nonlinear gene-environment interaction.  

PubMed

The genetic basis of blood pressure often involves multiple genetic factors and their interactions with environmental factors. Gene-environment interaction is assumed to play an important role in determining individual blood pressure variability. Older people are more prone to high blood pressure than younger ones and the risk may not display a linear trend over the life span. However, which gene shows sensitivity to aging in its effect on blood pressure is not clear. In this work, we allowed the genetic effect to vary over time and propose a varying-coefficient model to identify potential genetic players that show nonlinear response across different age stages. We detected 2 novel loci, gene MIR1263 (a microRNA coding gene) on chromosome 3 and gene UNC13B on chromosome 9, that are nonlinearly associated with diastolic blood pressure. Further experimental validation is needed to confirm this finding. PMID:25519336

Wang, Honglang; He, Tao; Wu, Cen; Zhong, Ping-Shou; Cui, Yuehua

2014-01-01

177

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Various Recipes of SiNx Passivated AlGaN/GaN High Electron Mobility Transistors in Correlation with Current Slump  

NASA Astrophysics Data System (ADS)

The current slump of different recipes of SiNx passivated AlGaN/GaN high electron mobility transistors (HEMTs) is investigated. The dc and pulsed current-voltage curves of AlGaN/GaN HEMTs using different recipes are analyzed. It is found that passivation leakage has a strong relationship with NH3 flow in the plasma-enhanced chemical vapor phase deposition process, which has impacted on the current collapse of SiNx passivated devices. We analyze the pulsed IDS - VDS characteristics of different recipes of SiNx passivation devices for different combinations of gate and drain quiescent biases (VGS0, VDS0) of (0, 0), (-6, 0), (-6, 15) and (0, 15)V. The possible mechanisms are the traps in SiNx passivation capturing the electrons and the surface states at the SiNx/AlGaN interface, which can affect the channel of two-dimensional electron gas and cause the current collapse.

Yang, Ling; Hao, Yue; Ma, Xiao-Hua; Quan, Si; Hu, Gui-Zhou; Jiang, Shou-Gao; Yang, Li-Yuan

2009-11-01

178

Glucocorticoid receptor gene polymorphisms and childhood adversity are associated with depression: New evidence for a gene-environment interaction.  

PubMed

The hypothalamic-pituitary-adrenal (HPA)-axis regulates the response to stressful events and is expected to be involved in the pathogenesis of depression. The glucocorticoid receptor (GR) regulates the activity of the HPA-axis. Both GR gene polymorphisms and childhood adversity are known to be associated with increased risk for depression. In the Longitudinal Aging Study Amsterdam, a large population based sample of older men and women, 906 subjects were genotyped. An association study was performed to determine the relationship between GR gene polymorphisms, childhood adversity, HPA-axis markers and depressive symptoms. A gene-environment interaction between the GR polymorphisms 22/23EK and 9beta and childhood adversity resulted in an increased risk of clinically relevant depressive symptoms. Without childhood adversity no increased risk was present. The 22/23EK variant was also associated with a lower Free Cortisol Index in the presence of childhood adversity. Persons that are heterozygous for the BclI variant, in contrast with wild-type and BclI-homozygotes, had lower serum levels of cortisol binding globulin and had no increased risk of recurrent depressive symptoms in the presence of childhood adversity. We found a gene-environment (G x E) interaction between common variants of the GR gene and childhood adversity, demonstrating a vulnerable phenotype for developing clinically relevant depressive symptoms at old age. This G x E interaction also influenced HPA-axis markers providing support for the involvement of the HPA-axis in both stress regulation and the pathogenesis of depression. PMID:19051288

Bet, Pierre M; Penninx, Brenda W J H; Bochdanovits, Zoltan; Uitterlinden, André G; Beekman, Aartjan T F; van Schoor, Natasja M; Deeg, Dorly J H; Hoogendijk, Witte J G

2009-07-01

179

Gene-environment and protein-degradation signatures characterize genomic and phenotypic diversity in wild Caenorhabditis elegans populations  

PubMed Central

Background Analyzing and understanding the relationship between genotypes and phenotypes is at the heart of genetics. Research on the nematode Caenorhabditis elegans has been instrumental for unraveling genotype-phenotype relations, and has important implications for understanding the biology of mammals, but almost all studies, including forward and reverse genetic screens, are limited by investigations in only one canonical genotype. This hampers the detection and functional analysis of allelic variants, which play a key role in controlling many complex traits. It is therefore essential to explore the full potential of the natural genetic variation and evolutionary context of the genotype-phenotype map in wild C. elegans populations. Results We used multiple wild C. elegans populations freshly isolated from local sites to investigate gene sequence polymorphisms and a multitude of phenotypes including the transcriptome, fitness, and behavioral traits. The genotype, transcriptome, and a number of fitness traits showed a direct link with the original site of the strains. The separation between the isolation sites was prevalent on all chromosomes, but chromosome V was the largest contributor to this variation. These results were supported by a differential food preference of the wild isolates for naturally co-existing bacterial species. Comparing polymorphic genes between the populations with a set of genes extracted from 19 different studies on gene expression in C. elegans exposed to biotic and abiotic factors, such as bacteria, osmotic pressure, and temperature, revealed a significant enrichment for genes involved in gene-environment interactions and protein degradation. Conclusions We found that wild C. elegans populations are characterized by gene-environment signatures, and we have unlocked a wealth of genotype-phenotype relations for the first time. Studying natural isolates provides a treasure trove of evidence compared with that unearthed by the current research in C. elegans, which covers only a diminutive part of the myriad of genotype-phenotype relations that are present in the wild. PMID:23957880

2013-01-01

180

Gene-environment interaction effects on lung function- a genome-wide association study within the Framingham heart study  

PubMed Central

Background Previous studies in occupational exposure and lung function have focused only on the main effect of occupational exposure or genetics on lung function. Some disease-susceptible genes may be missed due to their low marginal effects, despite potential involvement in the disease process through interactions with the environment. Through comprehensive genome-wide gene-environment interaction studies, we can uncover these susceptibility genes. Our objective in this study was to explore gene by occupational exposure interaction effects on lung function using both the individual SNPs approach and the genetic network approach. Methods The study population comprised the Offspring Cohort and the Third Generation from the Framingham Heart Study. We used forced expiratory volume in one second (FEV1) and ratio of FEV1 to forced vital capacity (FVC) as outcomes. Occupational exposures were classified using a population-specific job exposure matrix. We performed genome-wide gene-environment interaction analysis, using the Affymetrix 550 K mapping array for genotyping. A linear regression-based generalized estimating equation was applied to account for within-family relatedness. Network analysis was conducted using results from single-nucleotide polymorphism (SNP)-level analyses and from gene expression study results. Results There were 4,785 participants in total. SNP-level analysis and network analysis identified SNP rs9931086 (Pinteraction =1.16 × 10-7) in gene SLC38A8, which may significantly modify the effects of occupational exposure on FEV1. Genes identified from the network analysis included CTLA-4, HDAC, and PPAR-alpha. Conclusions Our study implies that SNP rs9931086 in SLC38A8 and genes CTLA-4, HDAC, and PPAR-alpha, which are related to inflammatory processes, may modify the effect of occupational exposure on lung function. PMID:24289273

2013-01-01

181

The hidden efficacy of interventions: gene×environment experiments from a differential susceptibility perspective.  

PubMed

The efficacy of interventions might be underestimated or even go undetected as a main effect when it is hidden in gene-by-environment (G×E) interactions. This review moves beyond the problems thwarting correlational G×E research to propose genetic differential susceptibility experiments. G×E experiments can test the bright side as well as the dark side of the moderating role of genotypes traditionally considered to represent vulnerability to negative conditions. The differential susceptibility model predicts that carriers of these risk genotypes profit most from interventions changing the environment for the better. The evolutionary background of G×E and differential susceptibility is discussed, and statistical methods for the analysis of differential susceptibility (versus diathesis stress) are reviewed. Then, based on results from 22 randomized G×E experiments, meta-analytic evidence for the differential susceptibility model is presented. Intervention effects are much stronger in the susceptible genotypes than in the nonsusceptible genotypes. The final sections suggest possibilities to broaden the G component in the G×E equation by including genetic pathways, and to broaden the E component by including methylation level and gene expression as promising ways to probe the concept of the environment more deeply and address the perennial issue of what works for whom. PMID:25148854

Bakermans-Kranenburg, Marian J; van IJzendoorn, Marinus H

2015-01-01

182

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

183

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

184

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

185

Ogawa ozone passive sampler range of measurements  

E-print Network

Capsule: upper detectable range of Ogawa ozone samplers is much greater than specified by the manufacturer. Test of the Ogawa ozone (O3) passive samplers were performed in continuously stirred tank reactors (CSTR) at controlled O3 concentrations. Concentrations determined with passive samplers and Dasibi Model 1003AH active UV absorption monitor were highly correlated (R 2 =0.9949). This linear relationship held up to a dose of 52,500 ppb O3 x h, indicating that the samplers are capable of reliable O3 monitoring for at least 477 hours at 110 ppb. This value is substantially higher than the upper detectable range specified by the manufacturer (<168 h at 110 ppb O3) indicating that ~ 3-times longer periods of passive sampler exposure can be applied. This finding also means that by extending sampler exposure times, costs of O3 monitoring can be significantly reduced.

Andrzej Bytnerowicz; Michael J. Arbaugh; Pamela E. Padgett; Antonio Davila

186

Validation of PhenX measures in the personalized medicine research project for use in gene/environment studies  

PubMed Central

Background The purpose of this paper is to describe the data collection efforts and validation of PhenX measures in the Personalized Medicine Research Project (PMRP) cohort. Methods Thirty-six measures were chosen from the PhenX Toolkit within the following domains: demographics; anthropometrics; alcohol, tobacco and other substances; cardiovascular; environmental exposures; cancer; psychiatric; neurology; and physical activity and physical fitness. Eligibility criteria for the current study included: living PMRP subjects with known addresses who consented to future contact and were not currently living in a nursing home, available GWAS data from eMERGE I for subjects where age-related cataract, HDL, dementia and resistant hypertension were the primary phenotypes, thus biasing the sample to the older PMRP participants. The questionnaires were mailed twice. Data from the PhenX measures were compared with information from PMRP questionnaires and data from Marshfield Clinic electronic medical records. Results Completed PhenX questionnaires were returned by 2271 subjects for a final response rate of 70%. The mean age reported on the PhenX questionnaire (73.1 years) was greater than the PMRP questionnaire (64.8 years) because the data were collected at different time points. The mean self-reported weight, and subsequently calculated BMI, were less on the PhenX survey than the measured values at the time of enrollment into PMRP (PhenX means 173.5 pounds and BMI 28.2 kg/m2 versus PMRP 182.9 pounds and BMI 29.6 kg/m2). There was 95.3% agreement between the two questionnaires about having ever smoked at least 100 cigarettes. 139 (6.2%) of subjects indicated on the PhenX questionnaire that they had been told they had a stroke. Of them, only 15 (10.8%) had no electronic indication of a prior stroke or TIA. All of the age-and gender-specific 95% confidence limits around point estimates for major depressive episodes overlap and show that 31% of women aged 50–64 reported symptoms associated with a major depressive episode. Conclusions The approach employed resulted in a high response rate and valuable data for future gene/environment analyses. These results and high response rate highlight the utility of the PhenX Toolkit to collect valid phenotypic data that can be shared across groups to facilitate gene/environment studies. PMID:24423110

2014-01-01

187

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

PubMed Central

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

Nickels, Stefan; Truong, Thérčse; 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; dos Santos Silva, Isabel; Peto, Julian; Humphreys, Manjeet K.; Wang, Jean; Cordina-Duverger, Emilie; Menegaux, Florence; Nordestgaard, Břrge 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; The GENICA Network; Mannermaa, Arto; Kataja, Vesa; Kosma, Veli-Matti; Hartikainen, Jaana M.; kConFab; Group, AOCS Management; Lambrechts, Diether; Smeets, Dominiek; Neven, Patrick; Paridaens, Robert; Flesch-Janys, Dieter; Obi, Nadia; Wang-Gohrke, Shan; Couch, Fergus J.; Olson, Janet E.; Vachon, Celine M.; Giles, Graham G.; Severi, Gianluca; Baglietto, Laura; Offit, Kenneth; John, Esther M.; Miron, Alexander; Andrulis, Irene L.; Knight, Julia A.; Glendon, Gord; Mulligan, Anna Marie; Chanock, Stephen J.; Lissowska, Jolanta; Liu, Jianjun; Cox, Angela; Cramp, Helen; Connley, Dan; Balasubramanian, Sabapathy; Dunning, Alison M.; Shah, Mitul; Trentham-Dietz, Amy; Newcomb, Polly; Titus, Linda; Egan, Kathleen; Cahoon, Elizabeth K.; Rajaraman, Preetha; Sigurdson, Alice J.; Doody, Michele M.; 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

188

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

189

Molecular Pathways: Gene-environment interactions regulating dietary fiber induction of proliferation and apoptosis via butyrate for cancer prevention  

PubMed Central

Gene-environment interactions are so numerous and biologically complicated that it can be challenging to understand their role in cancer. However, dietary fiber and colorectal cancer prevention may represent a tractable model system. Fiber is fermented by colonic bacteria into short-chain fatty acids such as butyrate. One molecular pathway that has emerged involves butyrate having differential effects depending on its concentration and the metabolic state of the cell. Low-moderate concentrations, which are present near the base of colonic crypts, are readily metabolized in the mitochondria to stimulate cell proliferation via energetics. Higher concentrations, which are present near the lumen, exceed the metabolic capacity of the colonocyte. Unmetabolized butyrate enters the nucleus and functions as a histone deacetylase (HDAC) inhibitor that epigenetically regulates gene expression to inhibit cell proliferation and induce apoptosis as the colonocytes exfoliate into the lumen. Butyrate may therefore play a role in normal homeostasis by promoting turnover of the colonic epithelium. Because cancerous colonocytes undergo the Warburg effect, their preferred energy source is glucose instead of butyrate. Consequently, even moderate concentrations of butyrate accumulate in cancerous colonocytes and function as HDAC inhibitors to inhibit cell proliferation and induce apoptosis. These findings implicate a bacterial metabolite with metaboloepigenetic properties in tumor suppression. PMID:24270685

Bultman, Scott J.

2013-01-01

190

Gene-Environment Interaction Effects on the Development of Immune Responses in the 1st Year of Life  

PubMed Central

Asthma is a common disease that results from both genetic and environmental risk factors. Children attending day care in the 1st year of life have lower risks for developing asthma, although the mechanism for this “day care” effect is largely unknown. We investigated the interactions between day care exposure in the 1st 6 mo of life and genotypes for 72 polymorphisms at 45 candidate loci and their effects on cytokine response profiles and on the development of atopic phenotypes in the 1st year of life in the Childhood Onset of Asthma (COAST) cohort of children. Six interactions (at four polymorphisms in three loci) with “day care” that had an effect on early-life immune phenotypes were significant at P<.001. The estimated false-discovery rate was 33%, indicating that an estimated four P values correspond to true associations. Moreover, the “day care” effect at some loci was accounted for by the increased number of viral infections among COAST children attending day care, whereas interactions at other loci were independent of the number of viral infections, indicating the presence of additional risk factors associated with day care environment. This study identified significant gene-environment interactions influencing the early patterning of the immune system and the subsequent development of asthma and highlights the importance of considering environmental risk factors in genetic analyses. PMID:15726497

Hoffjan, Sabine; Nicolae, Dan; Ostrovnaya, Irina; Roberg, Kathy; Evans, Michael; Mirel, Daniel B.; Steiner, Lori; Walker, Karen; Shult, Peter; Gangnon, Ronald E.; Gern, James E.; Martinez, Fernando D.; Lemanske, Robert F.; Ober, Carole

2005-01-01

191

Gene-environment interactions in determining differences in genetic susceptibility to cancer in subsites of the head and neck.  

PubMed

Genetic differences in susceptibility to cancer in subsites of the head and neck were investigated in a case-control study involving 750 cases of cancers of the oral cavity, larynx, or pharynx, and an equal number of healthy controls. The prevalence of variant genotypes of cytochrome P450 (CYP) 1A1, 1B1, 2E1, or glutathione-S-transferase M1 (null) in cases suggests that polymorphisms in drug metabolizing enzymes (DMEs) modify cancer risk within subsites of the head and neck. Tobacco or alcohol use was found to increase the risk in cases of laryngeal, pharyngeal, or oral cavity cancers. Interaction between genetic variation in DMEs and tobacco smoke (or smoking) exposures conferred significant risk for laryngeal cancer. Likewise, strong associations of the polymorphic genotypes of DMEs with cases of pharyngeal and oral cavity cancer who were tobacco chewers or alcohol users demonstrate that gene-environment interactions may explain differences in genetic susceptibility for cancers of the oral cavity, larynx, and pharynx. Environ. Mol. Mutagen. 56:313-321, 2015. © 2014 Wiley Periodicals, Inc. PMID:25399842

Maurya, Shailendra S; Katiyar, Tridiv; Dhawan, Ankur; Singh, Sudhir; Jain, Swatantra K; Pant, Mohan C; Parmar, Devendra

2015-04-01

192

Passive research and practice  

SciTech Connect

Passive-solar applications in buildings are described and examples are given to illustrate how research in the field has been approached. The major emphasis of the research has been on devising mathematical models to characterize heat flow within buildings, on the validation of these models by comparison with test results, and on the subsequent use of the models to investigate the influence of both various design parameters and the weather on system performance. Results from both test modules and monitored buildings are given. Simulation analysis, the development of simplified methods, and systems analysis are outlined. Passive-solar practice is described and the key elements that have led to successful passive-solar applications are discussed.

Balcomb, J.D.

1983-01-01

193

Passive solar retrofit guidebook  

SciTech Connect

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

Not Available

1981-01-01

194

Passive Microwave Measurements of Sea Surface Roughness  

Microsoft Academic Search

Passive microwave measurements of the sea surface were made from Argus Island tower at 1.41, 8.36, and 19.34 GHz over a range in wind speeds from calm to 15 m\\/s. These measurements show a definite frequency-dependent correlation between the microwave brightness temperature and wind speed. This dependence results from roughness effects of the compact sea surface associated with wind-driven waves.

James Hollinger

1971-01-01

195

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, Júlia 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

196

Novel Likelihood Ratio Tests for Screening Gene-Gene and Gene-Environment Interactions with Unbalanced Repeated-Measures Data  

PubMed Central

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 (ANOVA) 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

2013-01-01

197

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

198

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

199

Moderate alcohol consumption, dietary fat composition, and abdominal obesity in women: evidence for gene-environment interaction.  

PubMed

We examined relationships among alcohol intake, dietary fat composition, and total body fat (TBF) and central abdominal fat (CAF), independent of genetic confounders, and evaluated the modulating effect of genetic susceptibility. We studied 334 female twins (57.7 +/- 6.7 yr) after excluding dietary underreporters. Diet was assessed by Food-Frequency Questionnaire and body fat by dual-energy x-ray absorptiometry. Moderate alcohol consumers (12-17.9 g/d) had less TBF (20.6 +/- 5.6 vs. 24.8 +/- 8.4 kg, P = 0.03) and CAF (1.2 +/- 0.6 vs. 1.6 +/- 0.7 kg, P = 0.03) than abstainers. In multiple regression, alcohol consumption remained independently associated with body fat distribution. In cotwin case-control (monozygotic twin) analysis, moderate alcohol consumption accounted for 300 g less CAF, independent of genetic and other environmental factors. Gene-environment interaction analysis indicated that this association was limited to subjects at high genetic risk of abdominal obesity. There was no relationship between dietary fat composition and adiposity. However, in women at low genetic risk of abdominal obesity, subjects with polyunsaturated fat intakes in the highest tertile had about 50% less CAF than subjects with intakes in the lowest tertile (0.9 +/- 0.4 vs. 1.6 +/- 0.4 kg, P = 0.0007), an association absent in subjects with high genetic risk. In conclusion, genetic risk modulates relationships between dietary factors and adiposity. Lower abdominal fat may mediate associations between dietary intake and type 2 diabetes risk. PMID:14602777

Greenfield, Jerry R; Samaras, Katherine; Jenkins, Arthur B; Kelly, Paul J; Spector, Tim D; Campbell, Lesley V

2003-11-01

200

Moving to passive designs  

Microsoft Academic Search

The events at Fukushima Daiichi have greatly renewed the public focus on the safety of the existing fleet of nuclear reactors, especially as many US reactors share the same fundamental design—and safety systems—as the affected Japanese reactors. The authors explore the proposition that a transition to increasingly passive safety features in new advanced reactor designs— supplementing, and in some cases

Robert Rosner; Rebecca Lordan; Stephen Goldberg

2011-01-01

201

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. The design includes high R-Value assemblies, extremely tight construction, high performance doors and windows, solar thermal DHW, heat recovery ventilation, moveable external shutters and a high performance ductless mini-split heat pump. Cost analysis indicates that many of the measures implemented in this project did not meet the BA standard for cost neutrality. The ductless mini-split heat pump, lighting and advanced air leakage control were the most cost effective measures. The future challenge will be to value engineer the performance levels indicated here in modeling using production based practices at a significantly lower cost.

Hales, D.

2014-01-01

202

Passive in vivo elastography from skeletal muscle noise  

SciTech Connect

Measuring the in vivo elastic properties of muscles (e.g., stiffness) provides a means for diagnosing and monitoring muscular activity. The authors demonstrated a passive in vivo elastography technique without an active external radiation source. This technique instead uses cross correlations of contracting skeletal muscle noise recorded with skin-mounted sensors. Each passive sensor becomes a virtual in vivo shear wave source. The results point to a low-cost, noninvasive technique for monitoring biomechanical in vivo muscle properties. The efficacy of the passive elastography technique originates from the high density of cross paths between all sensor pairs, potentially achieving the same sensitivity obtained from active elastography methods.

Sabra, Karim G.; Conti, Stephane; Roux, Philippe; Kuperman, W. A. [Marine Physical Laboratory, Scripps Institution of Oceanography, University of California San Diego, San Diego, California 92093-0238 (United States)

2007-05-07

203

PRELIMINARY VALEN MODELING OF PASSIVE  

E-print Network

PRELIMINARY VALEN MODELING OF PASSIVE AND ACTIVE CONTROL OF RWM IN FIRE J. Bialek Columbia;VALEN Model of FIRE Passive & Active Stabilization 43210 -2 -1 0 1 2 z Z-vv Data from "dcon.FIRE.01" r z structure is computed w/o FIRE conducting wall. #12;VALEN Model of FIRE Passive Stabilization 1 0 0 1 0 - 1

204

Passive retrofit handbook: solar applications for residences  

SciTech Connect

The Handbook covers the following subjects: retrofit, passive solar, the passive solar window, the passive solar wall, the passive solar space, and materials and resources. Detailed construction drawings are included. (MHR)

Not Available

1980-01-01

205

Next-generation analysis of cataracts: determining knowledge driven gene-gene interactions using biofilter, and gene-environment interactions using the Phenx Toolkit*.  

PubMed

Investigating the association between biobank derived genomic data and the information of linked electronic health records (EHRs) is an emerging area of research for dissecting the architecture of complex human traits, where cases and controls for study are defined through the use of electronic phenotyping algorithms deployed in large EHR systems. For our study, cataract cases and controls were identified within the Marshfield Personalized Medicine Research Project (PMRP) biobank and linked EHR, which is a member of the NHGRI-funded electronic Medical Records and Genomics (eMERGE) Network. Our goal was to explore potential gene-gene and gene-environment interactions within these data for 527,953 and 527,936 single nucleotide polymorphisms (SNPs) for gene-gene and gene-environment analyses, respectively, with minor allele frequency > 1%, in order to explore higher level associations with cataract risk beyond investigations of single SNP-phenotype associations. To build our SNP-SNP interaction models we utilized a prior-knowledge driven filtering method called Biofilter to minimize the multiple testing burden of exploring the vast array of interaction models possible from our extensive number of SNPs. Using Biofilter, we developed 57,376 prior-knowledge directed SNP-SNP models to test for association with cataract status. We selected models that required 6 sources of external domain knowledge. We identified 13 statistically significant SNP-SNP models with an interaction with p-value < 1 × 10(-4), as well as an overall model with p-value < 0.01 associated with cataract status. We also conducted gene-environment interaction analyses for all GWAS SNPs and a set of environmental factors from the PhenX Toolkit: smoking, UV exposure, and alcohol use;these environmental factors have been previously associated with the formation of cataracts. We found a total of 782 gene-environment models that exhibit an interaction with a p-value < 1 × 10(-4) associatedwith cataract status. Our results show these approaches enable advanced searches for epistasis and gene-environment interactions beyond GWAS, and that the EHR based approach provides an additional source of data for seeking these advanced explanatory models of the etiology of complex disease/outcome such as cataracts. PMID:25741542

Pendergrass, Sarah A; Verma, Shefali S; Hall, Molly A; Holzinger, Emily R; Moore, Carrie B; Wallace, John R; Dudek, Scott M; Huggins, Wayne; Kitchner, Terrie; Waudby, Carol; Berg, Richard; Mccarty, Catherine A; Ritchie, Marylyn D

2015-01-01

206

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

207

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

208

Passive dynamic quadrupedal walking  

Microsoft Academic Search

It has been shown that a suitably designed biped will walk passively, i.e., without actuation or control, down a shallow slope. This paper extends the concept from bipedal to quadrupedal locomotion. A simple rimless-wheel model is analyzed first to provide a few basic insights, followed by a more complex model with freely-swinging legs. The gaits found for the quadruped are

Adam C. Smith; Matthew D. Berkemeier

1997-01-01

209

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

210

Folding in and out: passive morphing in flapping wings.  

PubMed

We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics as functions of the non-dimensional wingspan fold ratio (2-2.5) and flapping frequency (5-17 Hz) using stereo high-speed cameras. We find that the wings unfold passively within one to two flaps and remain unfolded with only small amplitude oscillations. To better understand the passive dynamics, we constructed a computer model of the unfolding process based on rigid body dynamics, contact models, and aerodynamic correlations. This model predicts the measured passive unfolding within about one flap and shows that unfolding is driven by centrifugal acceleration induced by flapping. The simulations also predict that relative unfolding time only weakly depends on flapping frequency and can be reduced to less than half a wingbeat by increasing flapping amplitude. Subsequent dimensional analysis shows that the time required to unfold passively is of the same order of magnitude as the flapping period. This suggests that centrifugal acceleration can drive passive unfolding within approximately one wingbeat in small and large wings. Finally, we show experimentally that passive unfolding wings can withstand impact with a branch, by first folding and then unfolding passively. This mechanism enables flapping robots to squeeze through clutter without sophisticated control. Passive unfolding also provides a new avenue in morphing wing design that makes future flapping morphing wings possibly more energy efficient and light-weight. Simultaneously these results point to possible inertia driven, and therefore metabolically efficient, control strategies in bats and birds to morph or recover within a beat. PMID:25807583

Stowers, Amanda K; Lentink, David

2015-04-01

211

Fundamental studies of passivity and passivity breakdown. Final report  

SciTech Connect

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

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

1991-11-01

212

Passive solar design handbook  

SciTech Connect

The Passive Solar Design Handbook, Volume Three updates Volume Two by presenting extensive new data on the optimum mix of conservation and solar direct gain, sunspaces, thermal storage walls, and solar radiation. The direct gain, thermal storage wall, and solar radiation data are greatly expanded relative to the Volume 2 coverage. The needed flexibility to analyze a variety of system designs is accommodated by the large number of reference designs to be encompassed - 94 in contrast to 6 in Volume two - and the large amount of sensitivity data for direct gain and sunspace systems - approximately 1100 separate curves.

Jones, R.W.

1981-01-01

213

Passive orbital disconnect strut  

NASA Technical Reports Server (NTRS)

The design and test results with a third generation passive orbital disconnect strut (PODS) for space-based cryogenic He dewars are presented. Three pairs of PODS struts support a tank and change lengths in response to gas and temperature changes. A thin wall fiberglass tube is used on the cold disconnect end, which can be operated on the ground or in space. Tests were performed to characterize heat flows across the cold end to a liquid He sink and subsequent vacuum pressure within the He tank. Heat transfer was lower than predicted, suggesting that longer dewar in-orbit lifetimes can be expected with the new PODS.

Parmley, R. T.; Kittel, P.

1984-01-01

214

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

215

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

216

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

217

Passive-solar construction handbook  

NASA Astrophysics Data System (ADS)

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

1981-09-01

218

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

219

Mechanical passive logic module  

NASA Astrophysics Data System (ADS)

Nothing from nothing gives simple simile, but something from nothing is an interesting and challenging task. Adolf Lohmann once proposed 'do nothing machine' in optics, which only copies input to output. Passive logic module (PALM) is a special type of 'do nothing machine' which can converts inputs into one of 16 possible binary outputs. This logic module is not like the conventional irreversible one. It is a simple type of reversible Turing machine. In this manuscript we discussed and demonstrated PALM using mechanical movement of plane mirrors. Also we discussed the theoretical model of micro electro mechanical system (MEMS) based PALM in this manuscript. It may have several valuable properties such as passive operation (no need for nonlinear elements as other logic device require) and modular logic (one device implementing any Boolean logic function with simple internal changes). The result is obtained from the demonstration by only looking up the output. No calculation is required to get the result. Not only that, PALM is a simple type of the famous 'billiard ball machine', which also discussed in this manuscript.

Chattopadhyay, Tanay; Caulfield, H. John

2015-02-01

220

A new passive helicopter detector  

SciTech Connect

Sandia has developed a new helicopter detector. The device relies on the correlation between the acoustic wave from the helicopter and the resulting coupled seismic wave. A significant feature of this approach is that the detector is completely passive; there is no radio frequency radiation. Intended for deployment as a perimeter sensor around a site, the unit offers a low nuisance/false alarm rate and a high probability of detection for a wide range of helicopters. Reliable detection occurs when the target is at high altitude and also very near the earth's surface. Detection ranges start at one kilometre for the small, four-place, civilian helicopter and approach five kilometres for heavier, military types. The system has two parts: a transducer package containing a microphone and a geophone and a digital processor. Development is underway for a model which will be AC powered and well suited to permanent facilities. A prototype unit using a lightweight, battery powered processor is being constructed for rapid-deployment applications.

Elliott, G.R.

1985-01-01

221

Commentary on "Capturing the Evasive Passive"  

ERIC Educational Resources Information Center

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

Lillo-Martin, Diane; Snyder, William

2009-01-01

222

Is the Gene-Environment Interaction Paradigm Relevant to Genome-Wide Studies? The Case of Education and Body Mass Index  

PubMed Central

This study uses data from the Framingham Heart Study to examine the relevance of the gene-environment interaction paradigm for genome-wide association studies (GWAS). We use completed college education as our environmental measure and estimate the interactive effect of genotype and education on body mass index (BMI) using 260,402 single-nucleotide polymorphisms (SNPs). Our results highlight the sensitivity of parameter estimates obtained from GWAS models and the difficulty of framing genome-wide results using the existing gene-environment interaction typology. We argue that SNP-environment interactions across the human genome are not likely to provide consistent evidence regarding genetic influences on health that differ by environment. Nevertheless, genome-wide data contain rich information about individual respondents, and we demonstrate the utility of this type of data. We highlight the fact that GWAS is just one use of genome-wide data, and we encourage demographers to develop methods that incorporate this vast amount of information from respondents into their analyses. PMID:24281739

Boardman, Jason D.; Domingue, Benjamin W.; Blalock, Casey L.; Haberstick, Brett C.; Harris, Kathleen Mullan; McQueen, Matthew B.

2014-01-01

223

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. 1 fig.

Forsberg, C.W.

1994-11-01

224

Robust passive piezoelectric shunt dampener  

Microsoft Academic Search

This paper introduces a new multiple mode passive piezoelectric shunt damping technique. The robust passive piezoelectric shunt controller is capable of damping multiple structural modes and maybe less susceptible to variations in environmental conditions that can severely effect the performance of other controllers. The proposed control scheme is validated experimentally on a piezoelectric laminated plate structure.

Sam Behrens; Andrew J. Fleming; S. O. R. Moheimani

2003-01-01

225

Passive solar heating for buildings  

Microsoft Academic Search

A survey of passive solar heating experience is presented. Design approaches reviewed include: (1) direct gain, (2) thermal storage wall, (3) attached sun space, (4) thermal storage loops, and (5) convective loop. Consideration is also given to generic categories: (a) direct, (b) indirect, and (c) isolated. Data is given showing that passive heating can be successful in regions such as

J. D. Balcomb

1979-01-01

226

CHAPTER 9CHAPTER 9CHAPTER 9:CHAPTER 9: Active and PassiveActive and Passive  

E-print Network

1 CHAPTER 9CHAPTER 9CHAPTER 9:CHAPTER 9: Active and PassiveActive and Passive Microwave RSMicrowave Hall Passive Remote SensingPassive Remote Sensing Passive remote sensing systems record electromagnetic infrared energy) from the surface of the E hEarth. #12;2 SSM/I Passive Microwave Radiometer Image of

Gilbes, Fernando

227

Passive magnetic bearing system  

DOEpatents

An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.

Post, Richard F.

2014-09-02

228

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

229

Passive containment cooling system  

DOEpatents

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

Billig, Paul F. (San Jose, CA); Cooke, Franklin E. (San Jose, CA); Fitch, James R. (San Jose, CA)

1994-01-01

230

Passive containment cooling system  

DOEpatents

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

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

1994-01-25

231

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 â??typically terminating fiber in the field.â?ť 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

232

The most energetic passive states  

E-print Network

Passive states are defined as those states that do not allow for work extraction in a cyclic (unitary) process. Within the set of passive states, thermal states are the most stable ones: they maximize the entropy for a given energy, and similarly they minimize the energy for a given entropy. In this article we find the passive states lying in the other extreme, i.e., those that maximize the energy for a given entropy, which we show also minimize the entropy when the energy is fixed. These extremal properties make these states useful to obtain fundamental bounds for the thermodynamics of finite dimensional quantum systems, which we show in several scenarios.

Martí Perarnau-Llobet; Karen V. Hovhannisyan; Marcus Huber; Paul Skrzypczyk; Jordi Tura; Antonio Acín

2015-02-25

233

Passive magnetic screening.  

PubMed

It is shown that a passive magnetic shield for a 1.5-T whole-body magnet requires about 20 tons of iron. Moreover, to first order, the amount of shielding material is independent of the radius of the shield. The choice between a thick shield fitting tightly round the magnet and a thinner shield of larger radius is determined by considerations of available space and the need for the highest uniformity of field in the bore. Very high permeability materials such as mu-metal are useful only in special circumstances. Multiple shields are valuable if a high degree of shielding is required, but the spacing between the shields needs careful attention. Although exact reciprocity of internal and external shielding is not found in the general case, the degree of shielding will be of the same order in both cases. The complete behavior of cylindrical shields around superconducting magnets can be determined by analytical solution of Maxwell's equations; for less regular shapes, solutions may be determined numerically by computer. PMID:2067396

Andrew, E R

1991-01-01

234

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

235

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

236

Orion Passive Thermal: Control Overview  

NASA Technical Reports Server (NTRS)

A general overview of the NASA Orion Passive Thermal Control System (PTCS) is presented. The topics include: 1) Orion in CxP Hierarchy; 2) General Orion Description/Orientation; and 3) Orion PTCS Overview.

Alvarez-Hermandez, Angel; Miller, Stephen W.

2009-01-01

237

Gene-environment interactions and the risk of childhood acute lymphoblastic leukemia: exploring the role of maternal folate genes and folic Acid fortification.  

PubMed

Few studies have evaluated the interaction of folic acid fortification and folate metabolic genes on the risk of childhood acute lymphoblastic leukemia (ALL). Because folate status is influenced by both intake and genetic variation, the objective of this study was to explore maternal folate metabolic gene-folic acid fortification interactions and the risk of childhood ALL. The study population consisted of 120 ALL case-parent triads recruited from Texas Children's Cancer Center between 2003 and 2010. For this analysis, we focused on 13 maternal single nucleotide polymorphisms (SNPs) in 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR). Prefortification was defined as delivery before January 1997 and postfortification as delivery in or after January 1997. We used a two-step approach to evaluate gene-environment interactions. First, a case-only approach was used, as this design provides greater power in the assessment of gene-environment interactions compared to other approaches. Second, we confirmed all statistically significant interactions using a log-linear approach among case-parent triads. Only one of 13 interactions evaluated was confirmed in step 2. Specifically, mothers with the minor allele of MTR rs1804742 and who delivered during the prefortification period were at a greater risk of having a child with ALL (OR = 1.54, 95% CI: 0.82-2.88), compared to those mothers who delivered during the postfortification period (OR = 0.81, 95% CI: 0.22-2.99, P for interaction = .03). In one of the few studies to evaluate maternal folate metabolic genotype-folic acid interactions, we found limited evidence that the maternal MTR rs1804742 appeared to interact with higher folic acid levels to influence childhood ALL risk. PMID:24087922

Lupo, Philip J; Dietz, Danielle J; Kamdar, Kala Y; Scheurer, Michael E

2014-03-01

238

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

239

Passive advection in nonlinear medium Michael Chertkov  

E-print Network

Passive advection in nonlinear medium Michael Chertkov Department of Physics, Princeton University, Princeton, New Jersey 08544 Received 23 September 1998; accepted 15 April 1999 Forced advection of passive on velocity, in com- parison with those of advection and nonlinearity, is called passive. The passiveness does

Chertkov, Mikhael

240

Passive Infinite-Dimensional Descriptor Systems  

E-print Network

Passive Infinite-Dimensional Descriptor Systems Timo Reis Birgit Jacob 1 Introduction We consider models [12]. In this work, the concept of input-output-passivity (io-passivity) is considered for systems of type (1). Io-passivity means that U = Y and that the real part of the Lebesgue inner product of input

Reis, Timo

241

Passive turbulent flamelet propagation  

NASA Technical Reports Server (NTRS)

We analyze results of a premixed constant density flame propagating in three-dimensional turbulence, where a flame model developed by Kerstein, et al. (1988) has been used. Simulations with constant and evolving velocity fields are used, where peculiar results were obtained from the constant velocity field runs. Data from the evolving flow runs with various flame speeds are used to determine two-point correlations of the fluctuating scalar field and implications for flamelet modeling are discussed.

Ashurst, William T.; Ruetsch, G. R.; Lund, T. S.

1994-01-01

242

Active and Passive Voice Recognizing the Active and the Passive Voice  

E-print Network

Active and Passive Voice Recognizing the Active and the Passive Voice "Voice" is the part to be in the "passive voice." Here are some examples: Active voice: He served us. Passive voice: We were served by him. Active voice: The dog chased the cat. Passive voice: The cat was chased by the dog. · It is generally

deYoung, Brad

243

PASSIVITY AND PASSIVITY BASED CONTROLLER DESIGN OF A CLASS OF SWITCHED CONTROL SYSTEMS  

Microsoft Academic Search

Notions of passivity for a class of switched control systems (SCS) are developed flrst in this article. We then study the following problems: 1) When is an SCS passive? 2) Does passivity imply Lyapunov stability as in the classical passive systems? 3) How to use passivity as a tool to design controllers to stabilize an SCS? For Problem 1), we

Weitian Chen; Mehrdad Saif

244

Passive Wake Vortex Control  

SciTech Connect

The collapse of the Soviet Union and ending of the Cold War brought about many significant changes in military submarine operations. The enemies that the US Navy faces today and in the future will not likely be superpowers armed with nuclear submarines, but rather smaller, rogue nations employing cheaper diesel/electric submarines with advanced air-independent propulsion systems. Unlike Cold War submarine operations, which occurred in deep-water environments, future submarine conflicts are anticipated to occur in shallow, littoral regions that are complex and noisy. Consequently, non-acoustic signatures will become increasingly important and the submarine stealth technology designed for deep-water operations may not be effective in these environments. One such non-acoustic signature is the surface detection of a submarine's trailing vortex wake. If a submarine runs in a slightly buoyant condition, its diving planes must be inclined at a negative angle of attack to generate sufficient downforce, which keeps the submarine from rising to the surface. As a result, the diving planes produce a pair of counter-rotating trailing vortices that propagate to the water surface. In previous deep-water operations, this was not an issue since the submarines could dive deep enough so that the vortex pair became incoherent before it reached the water surface. However, in shallow, littoral environments, submarines do not have the option of diving deep and, hence, the vortex pair can rise to the surface and leave a distinct signature that might be detectable by synthetic aperture radar. Such detection would jeopardize not only the mission of the submarine, but also the lives of military personnel on board. There has been another attempt to solve this problem and reduce the intensity of trailing vortices in the wakes of military submarines. The research of Quackenbush et al. over the past few years has been directed towards an idea called ''vortex leveraging.'' This active concept works by placing shape memory alloy (SMA) control surfaces on the submarine's diving planes and periodically oscillating them. The modulated control vortices generated by these surfaces interact with the tip vortices on the diving planes, causing an instability to rapidly occur. Though several numerical simulations have been presented, experimental verification does not appear to be available in the open literature. The authors address this problem through a concept called passive wake vortex control (PWVC), which has been demonstrated to rapidly break apart a trailing vortex wake and render it incoherent. PWVC functions by introducing unequal strength, counter-rotating control vortices next to the tip vortices. The presence of these control vortices destabilizes the vortex wake and produces a rapidly growing wake instability.

Ortega, J M

2001-10-18

245

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

246

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

247

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

248

Passive Evolution of Galaxy Clustering  

E-print Network

We present a numerical study of the evolution of galaxy clustering when galaxies flow passively from high redshift, respecting the continuity equation throughout. While passive flow is a special case of galaxy evolution, it allows a well-defined study of galaxy ancestry and serves as an interesting limit to be compared to non-passive cases. We use dissipationless N-body simulations, assign galaxies to massive halos at z=1 and z=2 using various HOD models, and trace these galaxy particles to lower redshift while conserving their number. We find that passive flow results in an asymptotic convergence at low redshift in the HOD and in galaxy clustering on scales above ~3Mpc/h for a wide range of initial HODs. As galaxies become less biased with respect to mass asymptotically with time, the HOD parameters evolve such that M1/Mm decreases while alpha converges toward unity, where Mm is the characteristic halo mass to host a central galaxy, M1 is the halo mass to host one satellite galaxy, and alpha is the power-law index in the halo-mass dependence of the average number of satellites per halo. The satellite populations converge toward the Poisson distribution at low redshift. The convergence is robust for different number densities and is enhanced when galaxies evolve from higher redshift. We compare our results with the observed LRG sample from Sloan Digital Sky Survey that has the same number density. We claim that if LRGs have experienced a strict passive flow, their should be close to a power law with an index of unity in halo mass. Discrepancies could be due to dry galaxy merging or new members arising between the initial and the final redshifts. The spatial distribution of passively flowing galaxies within halos appears on average more concentrated than the halo mass profile at low redshift. (abridged)

Hee-Jong Seo; Daniel J. Eisenstein; Idit Zehavi

2007-12-11

249

All-Passive Nonreciprocal Metasurface  

E-print Network

We introduce a systematic approach to design all-passive subwavelength high performance metasurfaces that exhibit nonreciprocal properties and achieve wave-flow isolation. Moreover we build upon those findings and propose a new paradigm for a quasi-2D metasurface that mimic the nonreciprocal property of Faraday rotation without using any magnetic or electric biasing. We envision that the proposed approaches may serve as a building block for all-passive time-reversal symmetry breaking with potential applications for future nonreciprocal systems and devices.

Mahmoud, Ahmed M; Engheta, Nader

2014-01-01

250

Passivation of high temperature superconductors  

NASA Technical Reports Server (NTRS)

The surface of high temperature superconductors such as YBa2Cu3O(7-x) are passivated by reacting the native Y, Ba and Cu metal ions with an anion such as sulfate or oxalate to form a surface film that is impervious to water and has a solubility in water of no more than 10(exp -3) M. The passivating treatment is preferably conducted by immersing the surface in dilute aqueous acid solution since more soluble species dissolve into the solution. The treatment does not degrade the superconducting properties of the bulk material.

Vasquez, Richard P. (inventor)

1991-01-01

251

Dynamics of Passive-Scalar Turbulence  

E-print Network

We present the first study of the dynamic scaling or multiscaling of passive-scalar and passive-vector turbulence. For the Kraichnan version of passive-scalar and passive-vector turbulence we show analytically, in both Eulerian and quasi-Lagrangian frameworks, that simple dynamic scaling is obtained but with different dynamic exponents. By developing the multifractal model we show that dynamic multiscaling occurs in passive-scalar turbulence only if the advecting velocity field is itself multifractal. We substantiate our results by detailed numerical simulations in shell models of passive-scalar advection.

Dhrubaditya Mitra; Rahul Pandit

2005-10-03

252

On passive adaptive mechanism in passive dynamic walking  

Microsoft Academic Search

In this paper, we point out that these results imply that the passive dynamic walker includes a kind of adaptive mechanism implicitly in its dynamics. Furthermore, we show some simulation results which show the existence of specific routes in adaptive and learning phenomenon. We claim that these results support the validity of a concept of canalization known in the field

Koihci Osuka

2007-01-01

253

ULTOR passive pose and position engine for spacecraft relative navigation  

Microsoft Academic Search

The ULTOR® Passive Pose and Position Engine (P3E) technology, developed by Advanced Optical Systems, Inc (AOS), uses real-time image correlation to provide relative position and pose data for spacecraft guidance, navigation, and control. Potential data sources include a wide variety of sensors, including visible and infrared cameras. ULTOR® P3E has been demonstrated on a number of host processing platforms. NASA

S. Joel Hannah

2008-01-01

254

Nevoid basal cell carcinoma syndrome with medulloblastoma in an African-American boy: A rare case illustrating gene-environment interaction  

SciTech Connect

We present an 8-year-old African-American boy with medulloblastoma and nevoid basal cell carcinoma syndrome (NBCCS) who exhibited the radiosensitive response of basal cell carcinoma (BCC) formation in the area irradiated for medulloblastoma. Such a response is well-documented in Caucasian NBCCS patients with medulloblastoma. The propositus was diagnosed with medulloblastoma at the age of 2 years and underwent surgery, chemotherapy, and craniospinal irradiation. At the age of 6 years, he was diagnosed with NBCCS following his presentation with a large odontogenic keratocyst of the mandible, pits of the palms and soles and numerous BCCs in the area of the back and neck that had been irradiated previously for medulloblastoma. Examination of other relatives showed that the propositus mother also had NBCCS but was more mildly affected; in particular, she had no BCCs. This case illustrates complex gene-environment interaction, in that increased skin pigmentation in African-Americans is presumably protective against ultraviolet, but not ionizing, radiation. This case and other similar cases in the literature show the importance of considering NBCCS in the differential diagnosis of any patient who presents with a medulloblastoma, especially before the age of 5 years, and of examining other close relatives for signs of NBCCS to determine the patient`s at-risk status. Finally, for individuals who are radiosensitive, protocols that utilize chemotherapy in lieu of radiotherapy should be considered. 27 refs., 4 figs.

Korczak, J.F.; Goldstein, A.M. [National Institutes of Health, Bethesda, MD (United States)] [National Institutes of Health, Bethesda, MD (United States); Kase, R.G. [Westat Inc., Rockville, MD (United States)] [and others] [Westat Inc., Rockville, MD (United States); and others

1997-03-31

255

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

256

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

PubMed Central

Background: The role of well-done meat intake and meat-derived mutagen heterocyclic amine (HCA) exposure in the risk of colorectal neoplasm has been suggested but not yet established. Objective: With the use of gene-environment interaction analyses, we sought to clarify the association of HCA exposure with colorectal polyp risk. Design: In a case-control study including 2057 colorectal polyp patients and 3329 controls, we evaluated 16 functional genetic variants to construct an HCA-metabolizing score. To derive dietary HCA-exposure amount, data were collected regarding dietary intake of meat by cooking method and degree of doneness. Results: A 2-fold elevated risk associated with high red meat intake was found for colorectal polyps or adenomas in subjects with a high HCA-metabolizing risk score, whereas the risk was 1.3- to 1.4-fold among those with a low risk score (P-interaction ? 0.05). The interaction was stronger for the risk of advanced or multiple adenomas, in which an OR of 2.8 (95% CI: 1.8, 4.6) was observed for those with both a high HCA-risk score and high red meat intake (P-interaction = 0.01). No statistically significant interaction was found in analyses that used specific HCA exposure derived from dietary data. Conclusion: High red meat intake is associated with an elevated risk of colorectal polyps, and this association may be synergistically modified by genetic factors involved in HCA metabolism. PMID:23015320

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

2012-01-01

257

Associations of PI3KR1 and mTOR Polymorphisms with Esophageal Squamous Cell Carcinoma Risk and Gene-Environment Interactions in Eastern Chinese Populations  

PubMed Central

Single nucleotide polymorphisms (SNPs) in the PI3K/PTEN/AKT/mTOR signaling pathway may contribute to carcinogenesis. We genotyped five potentially functional PIK3R1 and mTOR SNPs in 1116 esophageal squamous cell cancer (ESCC) patients and 1117 cancer-free controls to assess their associations with ESCC risk. We observed no association with ESCC risk for any of the selected SNPs. However, the combined analysis of these SNPs revealed that subjects with one-to-three risk genotypes had an increased ESCC risk. Stratified analysis by body mass index (BMI) found that ESCC risk was significantly associated with each of three mTOR SNPs among subjects with BMI < 25.0. Specifically, we found that subjects carrying ? 1 risk genotypes had significantly increased ESCC risk, particularly for males, ever-smokers, ever-drinkers, and those with age > 60, or BMI < 25.0. Moreover, three mTOR haplotypes were associated with an increase in ESCC risk. Our meta-analysis of mTOR rs2295080 and cancer risk provided further evidence that mTOR SNPs might modulate cancer susceptibility. In this population, such risk effects might be modified by other risk factors, highlighting the importance of gene-environment interaction in esophageal carcinogenesis. Additional, larger studies are warranted to validate our findings. PMID:25654238

Zhu, Jinhong; Wang, Mengyun; Zhu, Meiling; He, Jin; Wang, Jiu-Cun; Jin, Li; Wang, Xiao-Feng; Xiang, Jia-Qing; Wei, Qingyi

2015-01-01

258

Associations of PI3KR1 and mTOR polymorphisms with esophageal squamous cell carcinoma risk and gene-environment interactions in Eastern Chinese populations.  

PubMed

Single nucleotide polymorphisms (SNPs) in the PI3K/PTEN/AKT/mTOR signaling pathway may contribute to carcinogenesis. We genotyped five potentially functional PIK3R1 and mTOR SNPs in 1116 esophageal squamous cell cancer (ESCC) patients and 1117 cancer-free controls to assess their associations with ESCC risk. We observed no association with ESCC risk for any of the selected SNPs. However, the combined analysis of these SNPs revealed that subjects with one-to-three risk genotypes had an increased ESCC risk. Stratified analysis by body mass index (BMI) found that ESCC risk was significantly associated with each of three mTOR SNPs among subjects with BMI < 25.0. Specifically, we found that subjects carrying ? 1 risk genotypes had significantly increased ESCC risk, particularly for males, ever-smokers, ever-drinkers, and those with age > 60, or BMI < 25.0. Moreover, three mTOR haplotypes were associated with an increase in ESCC risk. Our meta-analysis of mTOR rs2295080 and cancer risk provided further evidence that mTOR SNPs might modulate cancer susceptibility. In this population, such risk effects might be modified by other risk factors, highlighting the importance of gene-environment interaction in esophageal carcinogenesis. Additional, larger studies are warranted to validate our findings. PMID:25654238

Zhu, Jinhong; Wang, Mengyun; Zhu, Meiling; He, Jin; Wang, Jiu-Cun; Jin, Li; Wang, Xiao-Feng; Xiang, Jia-Qing; Wei, Qingyi

2015-01-01

259

SEPIC converter passive components design  

Microsoft Academic Search

This paper presents a novel method for the design of passive components for battery powered SEPIC dc-dc switching regulators. The method is based on use of Acceptability Boundary Regions (ABR), which determine an area, in the space of parameters, corresponding to commercial components which ensure acceptable voltage ripples, fulfillment of maximum allowed power dissipation, and non pulsating source current absorption.

A. DeNardo; N. Femia; F. Forrisi; M. Granato

2008-01-01

260

Myths in passive solar design  

Microsoft Academic Search

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

S. Robert Hastings

1995-01-01

261

Passive smoking damages children's health.  

PubMed

Passive smoking in children accounts for an estimated 300,000 general practice consultations in the UK each year, the majority of which are for middle ear disease. There are also more than 100,000 asthma consultations in children attributable to passive smoking. Active maternal smoking causes up to about 5,000 miscarriages, 300 perinatal deaths, and 2,200 premature singleton births in the UK each year. Living in a household in which one or more people smoke more than doubles the risk of sudden infant death. Smoking by the mother increases the riskof lower respiratory infections by about 60%, and smoking by any household member by more than 50%. Passive smoking increases the risk of wheezing at all ages. The effect is strongest for smoking by the mother, with increases in risk of 65% to 77% according to the age of the child. It also increases the risk of asthma, with the risk increased by household smoking by about 50%, in school-aged children, and for middle ear disease, the risk is increased by about 35%. The simplest way to prevent passive exposure of children to tobacco smoke is to encourage and support their parents to quit smoking. PMID:20564879

Britton, John

2010-05-01

262

Orion Passive Thermal Control Overview  

NASA Technical Reports Server (NTRS)

An viewgraph presentation of Orion's passive thermal control system is shown. The topics include: 1) Orion in CxP Hierarchy; 2) General Orion Description/Orientation; 3) Module Descriptions and Images; 4) Orion PTCS Overview; 5) Requirements/Interfaces; 6) Design Reference Missions; 7) Natural Environments; 8) Thermal Models; 9) Challenges/Issues; and 10) Testing

Miller, Stephen W.

2007-01-01

263

Passive solar, country-style  

SciTech Connect

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

Miller, B.

1996-07-01

264

Monitored passive-solar buildings  

SciTech Connect

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. (LEW)

Jones, R.W. (comp.)

1982-06-01

265

The Passive Aggressive Conflict Cycle  

ERIC Educational Resources Information Center

Understanding the Passive Aggressive Conflict Cycle (PACC) helps observers to be able to look beyond behavior and better understand what is occurring beneath the surface. This article presents a real-life example of a seemingly minor conflict between a teacher and child that elicited an apparent major overreaction by the adult. Also provided is a…

Whitson, Signe

2013-01-01

266

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

267

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

SciTech Connect

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

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

1988-05-01

268

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

269

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

270

How to Make Theoretically Passive Reduced-Order Models Passive in Practice  

E-print Network

1 How to Make Theoretically Passive Reduced-Order Models Passive in Practice Zhaojun Bai Peter- stable and non-passive models even when such outcomes are theoretically proven to be impossibleMPVL that, even in practice, is guaranteedto produce stable and passive models for all the circuits

Bai, Zhaojun

271

Passive dynamic walking with elastic energy  

Microsoft Academic Search

This paper presents passive dynamic walking with elastic energy. We propose a new type of passive dynamic walking robot. by adding elastic materials such as spring or rubber between a supporting leg and a swing leg of the robot By utilizing restoring force of spring or rubber, we can make the passive dynamic walking robot easily walk since the crotch

Masahiro Mizuno; Hiroshi Ohtake; Kazuo Tanaka; Hua O. Wang

2008-01-01

272

PASSIVE FEEDFORWARD APPROACH TO BILATERAL TELEOPERATED MANIPULATORS  

E-print Network

PASSIVE FEEDFORWARD APPROACH TO BILATERAL TELEOPERATED MANIPULATORS #3; Perry Y. Li + and Dongjun bilateral teleoperated manipulator system which ensures that the closed loop system is energetically passive, and that the coupling between the system and any strictly passive environment is stable. The control objective

Li, Perry Y.

273

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

274

Imaging passive seismic data Brad Artman  

E-print Network

Imaging passive seismic data Brad Artman brad@sep.stanford.edu Submitted to Geophysics March 2005, CA 94305-2215 ABSTRACT Passive seismic imaging is the process of synthesizing the wealth to produce a subsurface image. For passively acquired data, migration is even more important than for active

275

Passive Scalar Evolution in Peripheral Region  

E-print Network

Passive Scalar Evolution in Peripheral Region V. V. Lebedev Landau Institute for Theoretical investigate the passive scalar (concentration of pollutants or temperature) evolution in the random (turbulent stages of the passive scalar homogenization (decay). There are some peculiarities of the decay related

Fominov, Yakov

276

Passivity Motivated Controller Design for Flexible Structures  

Microsoft Academic Search

When actuators and sensors on a controlled mechanical structure form naturally passive pairs, which usually requires physical collocation, very robust stabilizing controllers can be constructed. If the number of such naturally passive pairs is small, the closed loop performance may not be satisfactory. This motivates the incorporation of additional sensors in the control design. However, the passivity property no longer

Declan Hughes; John T. Wen

1993-01-01

277

Mechanical Computation for Passive Force Control  

Microsoft Academic Search

Force control implemented by a passive mechanical device (perhaps a wrist) has inherent advantages over active implementations. A passive mechanical device can regain some of the versatility of its active counterpart if it incorporates mechanical elements with programmable parameters, e.g. damping coefficients or spring stiffnesses. We wish to characterize the range of accommodation matrices that a passive device may be

Ambarish Goswami; Michael A. Peshkin

1993-01-01

278

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

279

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

SciTech Connect

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

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

1994-02-21

280

The Suppression of Immune System Disorders by Passive Attrition  

PubMed Central

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

Stromberg, Sean P.; Carlson, Jean M.

2010-01-01

281

Passive Standoff Detection of Chemical Warfare Agents on Surfaces  

NASA Astrophysics Data System (ADS)

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.

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

2004-11-01

282

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

Code of Federal Regulations, 2011 CFR

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2011-04-01

283

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

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Treatment of passive activity losses and passive activity credits in individuals' title 11 cases...Title 11 Cases § 1.1398-1 Treatment of passive activity losses and passive activity credits...

2012-04-01

284

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

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Treatment of passive activity losses and passive activity credits in individuals' title 11 cases...Title 11 Cases § 1.1398-1 Treatment of passive activity losses and passive activity credits...

2014-04-01

285

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

...2010-04-01 2010-04-01 true Treatment of passive activity losses and passive activity credits in individuals' title 11 cases...Title 11 Cases § 1.1398-1 Treatment of passive activity losses and passive activity credits...

2010-04-01

286

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

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Treatment of passive activity losses and passive activity credits in individuals' title 11 cases...Title 11 Cases § 1.1398-1 Treatment of passive activity losses and passive activity credits...

2013-04-01

287

Gene-environment interaction: Introduction  

Technology Transfer Automated Retrieval System (TEKTRAN)

The execution and completion of the Human Genome Project was surrounded by great expectations and many overstated promises, and for the first time in history, the information revolution has made of the general public a first row spectator of the scientific advances in real time. Therefore, the publi...

288

Interior design for passive solar homes  

SciTech Connect

The increasing emphasis on refinement of passive solar systems has brought recognition to interior design as an integral part of passive solar architecture. Interior design can be used as a finetuning tool minimizing many of the problems associated with passive solar energy use in residential buildings. In addition, treatment of interior space in solar model homes may be a prime factor in determining sales success. A new style of interior design is evolving in response to changes in building form incorporating passive solar design features. The psychology behind passive solar architecture is reflected in interiors, and selection of interior components increasingly depends on the functional suitability of various interior elements.

Breen, J. C.

1981-07-01

289

21. national passive solar conference: Proceedings. Volume 21  

Microsoft Academic Search

The 70 papers of this conference are arranged under the following topical sections: Passive case studies (7 papers); Daylighting (6); Passive solar cooling (6); School buildings (4); Passive charrettes (4); Emerging architecture (3); Community planning (5); Passive components and materials (9); Passive computer simulation (5); Passive metrics (7); Education and curriculum (9); and Public programs (6). All papers have been

R. Campbell-Howe; B. Wilkins-Crowder

1996-01-01

290

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

291

Robustness analysis based on passivity  

NASA Technical Reports Server (NTRS)

A technique of robust stability analysis for multivariable control systems is introduced. Existing tools in the literature are mostly based on small gain type of conditions such as the H(infinity)-norm or mu measure. In contrast, the approach presented is motivated by passivity theory. The natural energy Lyapunov function associated with a passive system allows robustness to be analyzed with Lyapunov stability theory. Consequently, nonlinear and time-varying perturbations can be considered within the same framework. For unstructured uncertainties, the robustness margin is characterized in terms of an index related to the Hermitian part of a transfer function. If the uncertainties contain additional diagonal structure, stability margins are obtained for variations of each uncertain block in both positive and negative directions. Applications of this robustness analysis technique are illustrated.

Wen, John T.

1988-01-01

292

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

PubMed

Nickel (?) is a toxic and carcinogenic metal which induces a redox imbalance following oxidative stress. Nuclear factor erythroid-2 related factor 2 (Nrf2) is a redox factor that regulates oxidation/reduction status and consequently mediates cytoprotective responses against exposure to environmental toxicants. In this study, we investigated the protective roles of the Nrf2 gene against oxidative stress and DNA damage induced by nickel at sub-lethal doses. Under nickel exposure conditions, we detected significantly increased intracellular ROS generation, in addition to higher amounts of DNA damage using comet assay and ?-H2AX immunofluorescence staining in Nrf2 lacking cells, as compared to Nrf2 wild-type cells. In addition, we attempted to identify potential nickel and Nrf2-responsive targets and the relevant pathway. The genomic expression data were analyzed using microarray for the selection of synergistic effect-related genes by Nrf2 knockdown under nickel treatment. In particular, altered expressions of 6 upregulated genes (CAV1, FOSL2, MICA, PIM2, RUNX1 and SLC7A6) and 4 downregulated genes (APLP1, CLSPN, PCAF and PRAME) were confirmed by qRT-PCR. Additionally, using bioinformatics tool, we found that these genes functioned principally in a variety of molecular processes, including oxidative stress response, necrosis, DNA repair and cell survival. Thus, we describe the potential biomarkers regarded as molecular candidates for Nrf2-related cellular protection against nickel exposure. In conclusion, these findings indicate that Nrf2 is an important factor with a protective role in the suppression of mutagenicity and carcinogenicity by environmental nickel exposure in terms of gene-environment interaction. PMID:23023193

Kim, Hye Lim; Seo, Young Rok

2012-12-01

293

Effect of TNF and LTA polymorphisms on biological markers of response to oxidative stimuli in coal miners: a model of gene-environment interaction  

PubMed Central

Introduction: Interaction between genetic background and oxidative environmental stimuli in the pathogenesis of human lung disease has been largely unexplored. Methods: A prospective epidemiological study was undertaken in 253 coal miners. Intermediate quantitative phenotypes of response to oxidant exposure, including erythrocyte glutathione peroxidase (GSH-Px) and catalase activities, were studied. Oxidant exposures studied were smoking habits and cumulative dust exposure assessed by job history and ambient measures. Disease phenotypes included subclinical computed tomography score at the first survey and x ray profusion grades twice, five years apart, to assess established coal workers' pneumoconiosis (CWP). Miners were genotyped for common functional polymorphisms in the gene for tumour necrosis factor ? (TNF) and lymphotoxin ? (LTA), two proinflammatory cytokines that have been implicated in the pathogenesis of chronic lung diseases. Results: Regarding gene-environment interaction on intermediate phenotypes, results showed interaction of a promoter polymorphism at the –308 position in TNF with occupational exposure on erythrocyte GSH-Px activity with a significant association in those with high exposure (p=0.003), whereas no association was observed among those with low exposure (interaction p=0.06). Regarding gene intermediate phenotype interaction on clinical outcome, results showed an association of CWP prevalence with an NcoI polymorphism in LTA in those with low catalase activity (p=0.05), whereas no association was observed in those with high activity (interaction p=0.03). No other significant association was observed. Conclusion: The results suggest that interactions of genetic background with environmental exposure and intermediate response phenotypes are important components in the pathogenesis of CWP. PMID:12566517

Nadif, R; Jedlicka, A; Mintz, M; Bertrand, J; Kleeberger, S; Kauffmann, F

2003-01-01

294

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

295

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

296

Retinopathy in old persons with and without diabetes mellitus: the Age, Gene/Environment Susceptibility—Reykjavik Study (AGES-R)  

PubMed Central

Aims/hypothesis We aimed to describe the prevalence of retinopathy in an aged cohort of Icelanders with and without diabetes mellitus. Methods The study population consisted of 4,994 persons aged ?67 years, who participated in the Age, Gene/Environment Susceptibility—Reykjavik Study (AGES-R). Type 2 diabetes mellitus was defined as HbA1c ?6.5% (>48 mmol/mol). Retinopathy was assessed by grading fundus photographs using the modified Airlie House adaptation of the Early Treatment Diabetic Retinopathy Study protocol. Associations between retinopathy and risk factors were estimated using odds ratios obtained from multivariate analyses. Results The overall prevalence of retinopathy in AGES-R was 12.4%. Diabetes mellitus was present in 516 persons (10.3%), for 512 of whom gradable fundus photos were available, including 138 persons (27.0%, 95% CI 23.2, 31.0) with any retinopathy. Five persons (1.0%, 95% CI 0.3, 2.3) had proliferative retinopathy. Clinically significant macular oedema was present in five persons (1.0%, 95% CI 0.3, 2.3). Independent risk factors for retinopathy in diabetic patients in a multivariate model included HbA1c, insulin use and use of oral hypoglycaemic agents, the last two being indicators of longer disease duration. In 4478 participants without diabetes mellitus, gradable fundus photos were available for 4,453 participants, with retinopathy present in 476 (10.7%, 95% CI 9.8, 11.6) and clinically significant macular oedema in three persons. Independent risk factors included increasing age and microalbuminuria. Conclusions/interpretation Over three-quarters (78%) of retinopathy cases were found in persons without diabetes and a strong association between microalbuminuria and non-diabetic retinopathy was found. These results may have implications for patient management of the aged. PMID:22134840

Gunnlaugsdottir, E.; Halldorsdottir, S.; Klein, R.; Eiriksdottir, G.; Klein, B. E.; Benediktsson, R.; Harris, T. B.; Launer, L. J.; Aspelund, T.; Gudnason, V.

2012-01-01

297

Interferoceiver, ISAR, and passive identification  

NASA Astrophysics Data System (ADS)

Optical fiber recirculation loops will change the technical foundation of radar and electronic warfare technologies. It becomes possible to measure Doppler beating with a single pulse, to map out micro Doppler signature with a resolution better than 1.0 Hz, and to take sharp IASR images of targets which are more than several hundred miles away. With fine micro Doppler signature and high precision ISAR images, the passive identification of targets will become a reality.

Li, Ming-Chiang

2006-05-01

298

Illegal Passive Smoking at Work  

PubMed Central

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

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

2011-01-01

299

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

300

Passive spatial beam control, appendix  

Microsoft Academic Search

This document discussed the following sections: Eclipsing Z-scan measurement of lambda\\/10(exp 4)wave-front distortion; Time-resolved Z-scan measurements of optical nonlinearities; Nondegenerate optical Kerr effect in semiconductors; Characterization of nonlinear optical absorption and referaction; High dynamic range passive optical limiters; Characterization of nonlinear absorption and refraction in advanced materials; Nonlinear optical materials at 10 micro m: from picoseconds to nanoseconds; Laser-induced acoustic

Eric W. Vanstryland

1994-01-01

301

Comparison of Different Haplotype-Based Haplotype-Based Association Methods for Gene-Environment (G×E) Interactions in Case-Control Studies when Haplotype-Phase Is Ambiguous  

Microsoft Academic Search

Objective: We compared four haplotype-based approaches for the analysis of gene-environment interactions when haplotype-phase is ambiguous. The methods employ different versions of the expectation maximization algorithm and differ in the choice of the reference group and in the way the risk of disease is modeled (retrospective versus prospective). Furthermore, the methods are based on distinct assumptions (such as Hardy Weinberg

Rebecca Hein; Lars Beckmann; Jenny Chang-Claude

2009-01-01

302

Dispersion analysis of passive surface-wave noise generated during hydraulic-fracturing operations  

NASA Astrophysics Data System (ADS)

Surface-wave dispersion analysis is useful for estimating near-surface shear-wave velocity models, designing receiver arrays, and suppressing surface waves. Here, we analyze whether passive seismic noise generated during hydraulic-fracturing operations can be used to extract surface-wave dispersion characteristics. Applying seismic interferometry to noise measurements, we extract surface waves by cross-correlating several minutes of passive records; this approach is distinct from previous studies that used hours or days of passive records for cross-correlation. For comparison, we also perform dispersion analysis for an active-source array that has some receivers in common with the passive array. The active and passive data show good agreement in the dispersive character of the fundamental-mode surface-waves. For the higher mode surface waves, however, active and passive data resolve the dispersive properties at different frequency ranges. To demonstrate an application of dispersion analysis, we invert the observed surface-wave dispersion characteristics to determine the near-surface, one-dimensional shear-wave velocity.

Forghani-Arani, Farnoush; Willis, Mark; Snieder, Roel; Haines, Seth S.; Behura, Jyoti; Batzle, Mike; Davidson, Michael

2014-12-01

303

Active and Passive Fields in Turbulent Transport: the Role of Statistically Preserved Structures  

E-print Network

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

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

2002-07-02

304

Passive solar reflector satellite revisited  

NASA Technical Reports Server (NTRS)

Passive light weight reflectors in space which direct the incident solar energy to a specified location on the Earth surface are proposed as an alternative system for the solar power satellite to overcome conversion losses and to avoid the need for photovoltaic cells. On Earth, either photovoltaic cells or a steam turbine alternator on a solar tower, or a similar conventional, relatively high efficiency cycle are used for electricity generation. The constraints which apply to the design of the optical system if a single satellite is placed in geostationary orbit are outlined. A single lens and a two lens system are discussed.

Polk, C.; Daly, J. C.

1980-01-01

305

Cardiac Hemodynamics are Linked With Structural and Functional Features of Brain Aging: The Age, Gene/Environment Susceptibility (AGES)?Reykjavik Study  

PubMed Central

Background Advanced heart failure is linked with structural and functional alterations in the brain. It is unclear whether a graded decrease in cardiac function puts older subjects at risk for brain aging. We investigated the association between cardiac hemodynamics and features of brain aging in community?dwelling older subjects. Methods and Results With data from a sub?study (n=931 subjects, mean age 75.9 years, 47.7% male) of the Age, Gene/Environment Susceptibility (AGES)?Reykjavik Study, we investigated the association of MRI measures of cardiac hemodynamics, including left ventricular stroke volume (LVSV) and cardiac output (CO) to brain characteristics. In multivariable analyses, each 10 mL lower LVSV was associated with 4.4 mL (95% CI 1.9 to 6.9) lower total parenchymal brain volume (TBV) and 3.7 mL (95% CI 1.8 to 5.7) lower gray matter volume (GMV). Likewise, each unit (L/min) lower CO was associated with 3.9 mL (95% CI 0.4 to 7.4) lower TBV and 3.9 mL (95% CI 0.4 to 7.4) lower GMV. Lower LVSV was associated with worse performance in processing speed (P=0.043) and executive function (P<0.001). Lower CO was associated with worse performance in processing speed (P=0.015) and executive function (P=0.003). Each 10 mL lower LVSV and each unit lower CO associated with a higher risk of mild cognitive impairment or dementia (odds ratio: 1.24, 95% CI 0.99 to 1.57 and odds ratio: 1.40, 95% CI 0.99 to 2.00, respectively). Conclusions A graded decrease in cardiac functioning is associated with features of brain aging. Older persons with cardiac or cognitive signs and symptoms may have both cardiac and cerebral diseases and should be evaluated accordingly. PMID:25628405

Sabayan, Behnam; van Buchem, Mark A.; Sigurdsson, Sigurdur; Zhang, Qian; Harris, Tamara B.; Gudnason, Vilmundur; Arai, Andrew E.; Launer, Lenore J.

2015-01-01

306

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

307

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

308

TORA example: cascade and passivity control designs  

Microsoft Academic Search

Considers the problem of feedback stabilization of translational oscillations by a rotational actuator (TORA system). The authors present several controller designs based on the cascade and passivity paradigms

Mrdjan Jankovic; Dan Fontaine; P. V. Kokotovic

1995-01-01

309

Passive cavitation imaging with ultrasound arrays  

PubMed Central

A method is presented for passive imaging of cavitational acoustic emissions using an ultrasound array, with potential application in real-time monitoring of ultrasound ablation. To create such images, microbubble emissions were passively sensed by an imaging array and dynamically focused at multiple depths. In this paper, an analytic expression for a passive image is obtained by solving the Rayleigh–Sommerfield integral, under the Fresnel approximation, and passive images were simulated. A 192-element array was used to create passive images, in real time, from 520-kHz ultrasound scattered by a 1-mm steel wire. Azimuthal positions of this target were accurately estimated from the passive images. Next, stable and inertial cavitation was passively imaged in saline solution sonicated at 520 kHz. Bubble clusters formed in the saline samples were consistently located on both passive images and B-scans. Passive images were also created using broadband emissions from bovine liver sonicated at 2.2 MHz. Agreement was found between the images and source beam shape, indicating an ability to map therapeutic ultrasound beams in situ. The relation between these broadband emissions, sonication amplitude, and exposure conditions are discussed. PMID:20000921

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

2009-01-01

310

Regulation of adult cardiocyte growth: effects of active and passive mechanical loading  

NASA Technical Reports Server (NTRS)

Fluctuations in hemodynamic load have been documented to modulate contractile protein turnover and myofibrillar structure in the heart; however, the relative importance of active and passive loading in regulating adult cardiocyte growth remains unresolved. To address this issue at the cellular level, adult feline cardiocytes were cultured either on Silastic membranes or plastic surfaces. Cardiocyte-laden membranes were stretched 10% of their rest length to enhance passive loading, whereas heart cells cultured on plastic or Silastic were field stimulated at 1 Hz to mimic active loading. Turnover of contractile proteins and structural integrity of the contractile-cytoskeletal apparatus were monitored for periods ranging from 4 to 72 h. Active and passive loading elevated contractile protein synthesis nearly equally (approximately 50%) and promoted the attachment of remodeled myofibrils to vinculin-positive focal contacts and/or costameres during the first 24 h of loading. Thereafter, rates of contractile protein synthesis returned to control values in passively stretched heart cells but remained elevated in field-stimulated cultures. The fractional rate of growth was increased significantly (approximately 8%/day) in electrically paced cells, whereas in passively stretched cardiocytes the growth rate rose only modestly (approximately 2%/day). Changes in the rate of myocyte growth appeared more closely correlated with the development of focal contacts and myofibril remodeling than with changes in myofibrillar protein turnover per se. 2,3-Butanedione monoxime, nifedipine, and, to a lesser extent, ryanodine blocked field-stimulated contractile protein synthesis and myofibrillar remodeling but had no impact on protein turnover or myofibril reassembly in passively loaded cardiocytes. The results of these experiments imply that both active and passive loading stimulate contractile protein turnover and myofibril remodeling, but the generation of active tension accelerates cardiocyte growth to a greater extent than passive loading. Furthermore, pharmacological interventions suggest that unique pathways may mediate these cellular events in actively and passively loaded adult cardiocytes.

Decker, M. L.; Janes, D. M.; Barclay, M. M.; Harger, L.; Decker, R. S.

1997-01-01

311

Applications of passivated silicon detectors  

NASA Astrophysics Data System (ADS)

We can postulate that dark matter are WIMPS, more specifically, Majorana particles called neutralinos floating through space. Upon neutralino-neutralino annihilation, they create a greater burst of other particles into space: these being all kinds of particles including anti-deuterons which are the indications of the existence of dark matter. For the study of the applications of passivated silicon detectors, this paper shows following procedures in two categories. Painting on little pieces of silicon (Polyimid and Boxcar Red) :Took clean paint brush and painted on Polyimid and Boxcar red samples onto little pieces of sample silicon and dried for a certain number of hours in different conditions. Cooling test : usually done in 7 cycles, cool until usually -35 degrees or -40 degrees Celsius with thermoelectric cooler, dry out, evapate the moisture in the fume hood, take pictures with the microscope and check for irregularities every 1, 4 and 7 times. The results show us how the passivated silicon will act in the real experiment--the vacuum chamber and x-rays (from the radioactive source), and different atmospheric pressures simulate what it will be like in space.

Kyung, Richard; Park, Chan Ho

2012-03-01

312

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.

313

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

314

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

315

An Event-Structural Account of Passive Acquisition in Korean  

ERIC Educational Resources Information Center

Some peculiar properties of children's passives have long been observed in various languages such as an asymmetry between actional passives and nonactional passives. These peculiarities have been accounted for under the hypothesis that children's early passives are adjectival, and as such exhibit properties of adjectival passives in adult grammar.…

Lee, Kwee-Ock; Lee, Youngjoo

2008-01-01

316

Turbulent transport of a passive-scalar field by using a renormalization-group method  

NASA Technical Reports Server (NTRS)

A passive-scalar field is considered to evolve under the influence of a turbulent fluid governed by the Navier-Stokes equation. Turbulent-transport coefficients are calculated by small-scale elimination using a renormalization-group method. Turbulent processes couple both the viscosity and the diffusivity. In the absence of any correlation between the passive-scalar fluctuations and any component of the fluid velocity, the renormalized diffusivity is essentially the same as if the fluid velocity were frozen, although the renormalized equation does contain higher-order nonlinear terms involving viscosity. This arises due to the nonlinear interaction of the velocity with itself. In the presence of a finite correlation, the turbulent diffusivity becomes coupled with both the velocity field and the viscosity. There is then a dependence of the turbulent decay of the passive scalar on the turbulent Prandtl number.

Hossain, Murshed

1992-01-01

317

Passive spatial mapping of inertial cavitation during HIFU exposure.  

PubMed

A novel method for mapping inertial cavitation activity during high-intensity focused ultrasound (HIFU) exposure is presented. Inertial cavitation has been previously shown to result in increased heat deposition and to be associated with broadband noise emissions that can be readily monitored using a passive receiver without interference from the main HIFU signal. In the present study, the signals received passively by each of 64 elements on a standard diagnostic array placed coaxially with the HIFU transducer are combined using time exposure acoustics to generate maps of inertially cavitating regions during HIFU exposure of an agar-based tissue-mimicking material. The technique is shown to be effective in localizing single-bubble activity, as well as contiguous and disjoint cavitating regions instigated by creating regions of lower cavitation threshold within the tissue phantom. The cavitation maps obtained experimentally are also found to be in good agreement with computational simulations and theoretical predictions. Unlike B-mode imaging, which requires interleaving with the HIFU pulse, passive array-based mapping of cavitation activity is possible during HIFU exposure. If cavitating regions can be directly correlated to increased tissue damage, this novel cavitation mapping technique could enable real-time HIFU treatment monitoring. PMID:19628450

Gyöngy, Miklós; Coussios, Constantin-C

2010-01-01

318

Strong local passivity in finite quantum systems  

NASA Astrophysics Data System (ADS)

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.

Frey, Michael; Funo, Ken; Hotta, Masahiro

2014-07-01

319

Simplified boiling water reactor passive safety features  

Microsoft Academic Search

This paper discusses the system functions and related hardware of key passive safety features of the simplified boiling water reactor (SBWR). The SBWR is a nominal 600-MW(electric) BWR that incorporates simplified systems and passive emergency equipment to enhance reactor operability and safety in an economical design that can be rapidly constructed. The SBWR reactor system is based on a nuclear

H. A. Upton; F. E. Cooke; J. K. Sawabe

1993-01-01

320

Manipulability of Cooperating Robots with Passive Joints  

Microsoft Academic Search

We study the differential kinematics and the kineto-static manipulability indices of multiple cooperating robot arms, including active and passive joints. The kinetic manipulability indices are derived as a simple extension of previous results on cooperating robots without passive joints. The force manipulability analysis for cooperative robot systems can not be derived by “duality” arguments as it can with conventional arms,

Antonio Bicchi; Domenico Prattichizzo

1998-01-01

321

Wide band passive repeaters: Design and measurements  

Microsoft Academic Search

The performances of a wideband passive repeater including two broadband antennas and a coaxial line are analyzed both from full-wave electromagnetic simulations and measurement data over 1.6 GHz bandwidth centered at 4 GHz. For carrier signal level lower than the detection threshold, the use of passive repeater can significantly improve the reliability of the wireless link.

A. Ali; A. Coustou; H. Aubert

2009-01-01

322

Passive filter design using genetic algorithms  

Microsoft Academic Search

The objective of this paper is to propose a new approach for designing a passive LC filter of the full-bridge rectifier by using genetic algorithms (GAs). The performance of the cost-effective passive LC filter for a constant load depends on the appropriate inductor and capacitor selection. Several design methods are reviewed and a novel design methodology using GAs is proposed

Yaow-Ming Chen

2003-01-01

323

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.

324

Aeroelastic stability analysis and passive instability suppression  

E-print Network

using parameter variations to support the design of turbines with good passive stability propertiesAeroelastic stability analysis and passive instability suppression Thomas Buhl, Helen Markou author: thomas.buhl@risoe.dk Abstract: Aeroelastic stability issues become more important in the design

325

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...

326

Coupled stability characteristics of nearly passive robots  

Microsoft Academic Search

The authors address the problem of designing manipulator control laws such that interaction between manipulator and environment is stable. Taking passive manipulator admittance as a design goal. a metric that bounds the distance between the achieved nonpassive response and a passive target response is introduced. Conditions for coupled stability are developed based on this measure of admittance error, which result

Jim D. Chapel; R. Su

1992-01-01

327

Passive ice freezing-releasing heat pipe  

DOEpatents

A heat pipe device has been developed which permits completely passive ice formation and periodic release of ice without requiring the ambient temperature to rise above the melting point of water. This passive design enables the maximum amount of cooling capacity to be stored in the tank.

Gorski, Anthony J. (Lemont, IL); Schertz, William W. (Batavia, IL)

1982-01-01

328

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

329

Passive Cooling for Your North Carolina Home  

E-print Network

Passive Cooling for Your North Carolina Home As energy costs rise, and the public becomes more into passive or active solar heating as a way of reducing the amount of energy used in their home. In most in the home is as follows: Block heat from entering Minimize heat generated Ventilate to remove heat

330

Detection of a Virtual Passive Pointer  

Microsoft Academic Search

The paper presents a methodology for detecting a virtual passive pointer. The passive pointer or device does not have any active energy source within it (as opposed to a laser pointer) and thus cannot easily be detected or identified. The modeling and simulation task is carried out by generating high resolution color images of a pointer viewing via two digital

Naren Vir; Shaleen Vir

331

Surface passivation for germanium photovoltaic cells  

Microsoft Academic Search

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

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

2005-01-01

332

A photoelectrochemical investigation of passive films formed by alternating voltage passivation  

SciTech Connect

Photocurrent measurements for stainless steel type 304 in the as-received condition after dc and AV (alternating voltage) passivation have confirmed that significant changes of the passive film properties occur due to AV passivation. The photocurrents were the highest for the sample treated by the AV passivation process (AVPP). The bandgap energy increased from about 2.8 to about 3.05 eV for this treatment. Very similar results have been obtained for pure chromium, which suggests that the AVPP produces a thicker passive film with a less defective nature due to a partial dehydration of the chromium oxide phase in the film.

Schmuki, P.; Boehni, H. (Swiss Federal Inst. of Technology, Zuerich (Switzerland). Inst. of Materials Chemistry and Corrosion); Mansfeld, F. (Univ. of Southern California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering)

1993-07-01

333

Universal long-time properties of Lagrangian statistics in the Batchelor regime and their application to the passive scalar problem  

E-print Network

We consider transport of dynamically passive quantities in the Batchelor regime of smooth in space velocity field. For the case of arbitrary temporal correlations of the velocity we formulate the statistics of relevant characteristics of Lagrangian motion. This allows to generalize many results obtained previously for the delta-correlated in time strain, thus answering the question of universality of these results.

E. Balkovsky; A. Fouxon

1999-08-31

334

Passive States for Essential Observers  

E-print Network

The aim of this note is to present a unified approach to the results given in \\cite{bb99} and \\cite{bs04} which also covers examples of models not presented in these two papers (e.g. $d$-dimensional Minkowski space-time for $d\\geq 3$). Assuming that a state is passive for an observer travelling along certain (essential) worldlines, we show that this state is invariant under the isometry group, is a KMS-state for the observer at a temperature uniquely determined by the structure constants of the Lie algebra involved and fulfills (a variant of) the Reeh-Schlieder property. Also the modular objects associated to such a state and the observable algebra of an observer are computed and a version of weak locality is examined.

Robert Strich

2008-01-23

335

Passive phase noise cancellation scheme.  

PubMed

We introduce a new method for reducing phase noise in oscillators, thereby improving their frequency precision. The noise reduction is realized by a passive device consisting of a pair of coupled nonlinear resonating elements that are driven parametrically by the output of a conventional oscillator at a frequency close to the sum of the linear mode frequencies. Above the threshold for parametric instability, the coupled resonators exhibit self-oscillations which arise as a response to the parametric driving, rather than by application of active feedback. We find operating points of the device for which this periodic signal is immune to frequency noise in the driving oscillator, providing a way to clean its phase noise. We present results for the effect of thermal noise to advance a broader understanding of the overall noise sensitivity and the fundamental operating limits. PMID:23004985

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

2012-06-29

336

Passive Phase Noise Cancellation Scheme  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

337

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

338

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

339

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

SciTech Connect

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

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

1993-02-01

340

Research on sub-pixel accuracy displacement estimation for Passive Millimeter Wave multi-frame Imaging  

Microsoft Academic Search

Passive Millimeter Wave (PMMW) multi-frame Imaging displacement estimation is a key procedure before Super-Resolution Reconstruction. In this paper, a novel method based on Phase-Only Correlation and IDFT for motion estimation is presented. Experimental data demonstrates that the proposed algorithm yields higher accuracy sub-pixel level motion estimation and proves the effectiveness and adaptiveness of this algorithm.

Xiang Shi; Jintao Xiong; Liangchao Li; Jianyu Yang

2011-01-01

341

Passive Ventricular Mechanics Modelling Using MRI of Structure and Function  

PubMed Central

Patients suffering from dilated cardiomyopathy or myocardial infarction can develop left ventricular (LV) diastolic impairment. The LV remodels its structure and function to adapt to pathophysiological changes in geometry and loading conditions and this remodeling process can alter the passive ventricular mechanics. In order to better understand passive ventricular mechanics, a LV finite element model was developed to incorporate physiological and mechanical information derived from in vivo magnetic resonance imaging (MRI) tissue tagging, in vivo LV cavity pressure recording and ex vivo diffusion tensor MRI (DTMRI) of a canine heart. MRI tissue tagging enables quantitative evaluation of cardiac mechanical function with high spatial and temporal resolution, whilst the direction of maximum water diffusion (the primary eigenvector) in each voxel of a DTMRI directly correlates with the myocardial fibre orientation. This model was customized to the geometry of the canine LV during diastasis by fitting the segmented epicardial and endocardial surface data from tagged MRI using nonlinear finite element fitting techniques. Myofibre orientations, extracted from DTMRI of the same heart, were incorporated into this geometric model using a free form deformation methodology. Pressure recordings, temporally synchronized to the tissue tagging MRI data, were used to simulate the LV deformation during diastole. Simulation of the diastolic LV mechanics allowed us to estimate the stiffness of the passive LV myocardium based on kinematic data obtained from tagged MRI. This integrated physiological model will allow more insight into the regional passive diastolic mechanics of the LV on an individualized basis, thereby improving our understanding of the underlying structural basis of mechanical dysfunction in pathological conditions. PMID:18982680

Wang, V.Y.; Lam, H.I.; Ennis, D.B.; Young, A.A.; Nash, M.P.

2009-01-01

342

Passive Haptics Significantly Enhances Virtual Environments Brent Edward Insko  

E-print Network

Passive Haptics Significantly Enhances Virtual Environments by Brent Edward Insko A dissertation Edward Insko ALL RIGHTS RESERVED #12;iii ABSTRACT BRENT EDWARD INSKO: Passive Haptics Significantly objects. I hypothesize that passive haptics, augmenting a high-fidelity visual virtual environment

Whitton, Mary C.

343

76 FR 72875 - Passive Activity Losses and Credits Limited  

Federal Register 2010, 2011, 2012, 2013, 2014

...Part 1 [REG-109369-10] RIN 1545-BJ33 Passive Activity Losses and Credits Limited AGENCY...of certain taxpayers to deduct losses from passive activities. Section 469(b) permits passive losses disallowed in one year to be...

2011-11-28

344

48 CFR 252.211-7006 - Passive Radio Frequency Identification.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Passive Radio Frequency Identification. 252.211-7006...And Clauses 252.211-7006 Passive Radio Frequency Identification. As prescribed... , use the following clause: Passive Radio Frequency Identification (SEP 2011)...

2012-10-01

345

Are Passive Spiral Galaxies truly 'passive' and 'spiral'?: a Near-Infrared perspective  

E-print Network

Passive spiral galaxies - unusual galaxies with spiral morphologies but without any sign of on-going star formation - have recently been shown to exist preferentially in cluster infalling regions. This discovery directly connects passive spiral galaxies to cluster galaxy evolution studies, such as the Butcher-Oemler effect or the morphology-density relation. Thus, detailed study of passive spiral galaxies could potentially yield new insight on the underlying physical mechanisms governing cluster galaxy evolution. However, in previous work, passive spiral galaxies were selected from low-resolution optical images with $\\sim$1.5 arcsec seeing. Passive spirals could therefore be mis-identified as S0 galaxies, or as dusty-starburst galaxies which are not passive at all. To address this issue we performed deep, high-resolution, near-infrared imaging of 32 passive spiral galaxies with UKIRT.

Chisato Yamauchi; Tomotsugu Goto

2005-07-05

346

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

347

The Self-Report Psychopathy Scale and passive avoidance learning: a validation study of race and gender effects.  

PubMed

The reliability and validity of the Self-Report Psychopathy Scale (SRPS) was examined in a noninstitutionalized offender sample of mixed gender and race. Adequate alpha coefficients were obtained for the total sample and across gender and race. The SRPS was compared to measures of trait anxiety and passive avoidance errors. SRPS total, primary, and secondary scores were positively and significantly correlated with trait anxiety and passive avoidance (commission) errors, but not omission errors. Employing hierarchical regression models, no anxiety, gender, or ethnic effects were found. Intelligence confounded the relationship between psychopathic traits and passive avoidance errors. Findings provide tentative support of the SRPS as a valid measure of psychopathy. PMID:16672734

Epstein, Monica K; Poythress, Norman G; Brandon, Karen O

2006-06-01

348

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

2009-11-01

349

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

350

Spatially Resolved Spectroscopy of Passive Spiral Galaxies  

E-print Network

Passive spiral galaxies, despite their spiral morphological appearance, do not have any emission lines indicative of ongoing star formation in their optical spectra. Previous studies have suggested that passive spiral galaxies preferentially exist in infall regions of galaxy clusters, suggesting that the cluster environment is likely to be responsible for creating these galaxies. By carrying out spatially resolved long-slit spectroscopy on four nearby passive spiral galaxies with the Apache Point Observatory 3.5-m telescope, we investigated the stellar populations of passive spiral galaxies separately for their inner and outer regions. In the two unambiguously passive spiral galaxies among the four observed galaxies, H$\\delta$ absorption lines are more prominent in the outer regions of the galaxies, whereas the 4000-{\\AA} breaks (D$_{4000}$) are strongest in the inner regions of the galaxies. A comparison with a simple stellar population model for the two passive spiral galaxies indicates that the outer regions of the galaxies tend to harbour younger populations of stars. The strong H$\\delta$ absorption observed in the outer regions of the sample galaxies is consistent with that of galaxies whose star formation ceased a few Gyrs ago. Because of the large uncertainty in the absorption indices in our samples, further observations are needed in order to place constraints on the mechanisms that quench star formation in passive spiral galaxies.

Miho Ishigaki; Tomotsugu Goto; Hideo Matsuhara

2008-01-07

351

Transport of passive scalars in a turbulent channel flow  

NASA Technical Reports Server (NTRS)

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

Kim, John; Moin, Parviz

1987-01-01

352

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

353

Los Alamos National Laboratory passive solar program  

SciTech Connect

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

Neeper, D.A.

1981-01-01

354

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 Săo 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

355

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

356

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

357

Passive Leg Raising during Pregnancy.  

PubMed

Objective?To determine if passive leg raising (PLR) significantly increases cardiac output in a cohort of healthy pregnant women during the third trimester. Study Design?Using a noninvasive monitor, baseline hemodynamic measurements for arterial blood pressure, systolic and diastolic blood pressure, heart rate, cardiac output, cardiac index, stroke volume, and systemic vascular resistances were obtained with patients in the semirecumbent position. Measurements were repeated after a 3-minute PLR maneuver in supine, right lateral decubitus, and left lateral decubitus positions. Results?After 10 minutes of bed rest, the cohort's mean baseline heart rate was 80?±?12 beats/minute. Baseline stroke volume was 98?±?14 mL, mean cardiac output was 7.8?±?1.2 L/min, and mean cardiac index was 4.32?±?0.63 L/min. The baseline systemic vascular resistance value was 893?±?160 dynes/sec/cm(5). Baseline mean arterial blood pressure was 84?±?11?mm Hg. Following a PLR maneuver in the supine position, heart rate decreased significantly. No difference was noted in other measurements. Findings were similar with PLR in the left lateral decubitus. PLR in the right lateral decubitus resulted in significantly decreased heart rate, cardiac output, and cardiac index. Conclusions?PLR did not result in cardiac output recruitment in a cohort of healthy pregnant women during the third trimester. PMID:25241109

Marques, Nicole Ribeiro; Martinello, Caroline; Kramer, George C; Costantine, Maged M; Vadhera, Rakesh B; Saade, George R; Hankins, Gary D; Pacheco, Luis D

2015-03-01

358

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

359

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

360

[Passive euthanasia and living will].  

PubMed

This article deals with the intentional distinction between murder of first degree and passive euthanasia. In Hungary, active euthanasia is considered to be a murder of first degree, whilst the Netherlands, Belgium, Luxemburg and Switzerland have legalized the active form of mercy killing in Europe. The palliative terminal care, when e.g. giving pain-killer morphine to the patient, might result in decreasing the patient's life-span, and thus causing indirect euthanasia. However, the legal institution of living will exists in several counter-euthanasia countries. The living will allows future patients to express their decision in advance to refuse a life-sustaining treatment, e.g. in case of irreversible coma. The institution of living will exists in Germany and in Hungary too. Nevertheless, the formal criteria of living will make it hardly applicable. The patient ought to express his/her will before a notary public in advance, and he/she should hand it over when being hospitalized. If the patient is not able to present his/her living will to his/her doctor in the hospital, then his/her only hope remains that he/she has given a copy of the living will to the family doctor previously, and the family doctor will notify the hospital. PMID:24974840

Julesz, Máté

2014-07-01

361

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

362

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

363

Optical Correlation  

NASA Technical Reports Server (NTRS)

Pattern recognition may supplement or replace certain navigational aids on spacecraft in docking or landing activities. The need to correctly identify terrain features remains critical in preparation of autonomous planetary landing. One technique that may solve this problem is optical correlation. Correlation has been successfully demonstrated under ideal conditions; however, noise significantly affects the ability of the correlator to accurately identify input signals. Optical correlation in the presence of noise must be successfully demonstrated before this technology can be incorporated into system design. An optical correlator is designed and constructed using a modified 2f configuration. Liquid crystal televisions (LCTV) are used as the spatial light modulators (SLM) for both the input and filter devices. The filter LCTV is characterized and an operating curve is developed. Determination of this operating curve is critical for reduction of input noise. Correlation of live input with a programmable filter is demonstrated.

Cotariu, Steven S.

1991-01-01

364

Passive imaging with pulsed ultrasound insonations  

PubMed Central

Previously, passive cavitation imaging has been described in the context of continuous-wave high-intensity focused ultrasound thermal ablation. However, the technique has potential use as a feedback mechanism for pulsed-wave therapies, such as ultrasound-mediated drug delivery. In this paper, results of experiments and simulations are reported to demonstrate the feasibility of passive cavitation imaging using pulsed ultrasound insonations and how the images depend on pulsed ultrasound parameters. The passive cavitation images were formed from channel data that was beamformed in the frequency domain. Experiments were performed in an invitro flow phantom with an experimental echo contrast agent, echogenic liposomes, as cavitation nuclei. It was found that the pulse duration and envelope have minimal impact on the image resolution achieved. The passive cavitation image amplitude scales linearly with the cavitation emission energy. Cavitation images for both stable and inertial cavitation can be obtained from the same received data set. PMID:22779500

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

2012-01-01

365

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

366

Method and structure for passivating semiconductor material  

DOEpatents

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

Pankove, Jacques I. (Princeton, NJ)

1981-01-01

367

PASSIVE MICROWAVE REMOTE SENSING FOR LAND APPLILCATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

368

Low-cost passive solar demonstration project  

SciTech Connect

The demonstration project is described. The specifications and blueprints of the projects passive solar home are presented. The project has data direct gain and a Trombe wall. It is designed for standard building techniques in the southwest. (MHR)

Not Available

1980-05-15

369

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

370

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

PubMed Central

Psychopathy is a constellation of self-serving attitudes and antisocial behaviors with little regard to cost to self and others. Might this symptomatology arise in part from an exaggerated response of brain motivational circuitry to prospective rewards? We examined whether psychopathic tendencies are associated with increased recruitment of incentive neurocircuitry during anticipation of instrumental and conditioned rewards. Healthy controls completed the Psychopathic Personality Inventory (PPI), then were presented with response-contingent and passively-delivered rewards during functional MRI. PPI scores correlated negatively with reaction time to incentivized targets, but not with reaction time to non-incentivized targets. PPI scores also correlated positively with recruitment of ventral striatum and anterior cingulate cortex during reward instrumental anticipation. PPI scores also correlated with middle frontal cortex recruitment during anticipation of passively-received rewards. These data indicate that in psychiatrically-healthy controls, individuals with greater endorsement of psychopathic tendencies show more robust neurophysiological and behavioral signatures of incentive motivation. PMID:22178441

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

2012-01-01

371

Passive tick surveillance, dog seropositivity, and incidence of human Lyme disease  

USGS Publications Warehouse

Data on nymphal Ixodes scapularis ticks submitted by the public to the University of Rhode Island Tick Research Laboratory for testing from 1991 to 2000 were compared with human case data from the Rhode Island Department of Health to determine the efficacy of passive tick surveillance at assessing human risk of Lyme disease. Numbers of ticks submitted were highly correlated with human cases by county (r = 0.998, n = 5 counties) and by town (r = 0.916, n = 37 towns), as were the numbers of positive ticks submitted (r = 0.989 by county, r = 0.787 by town). Human cases were correlated with ticks submitted by town each year, and with positive ticks in all but 2 years. Thus, passive tick surveillance effectively assessed geographical risk of human Lyme disease. In contrast, tick submissions through time were not correlated with human cases from year to year. Dog seropositivity was significantly correlated with human cases by county in both years tested, but by town in only one of two years. Numbers of ticks submitted were correlated with dog seropositivity by county but not by town, apparently because of high variability among towns with small sample sizes. Our results suggest that passive tick surveillance, using ticks submitted by the public for Lyme spirochete testing, can be used to assess the geographical distribution of Lyme disease risk, but cannot reliably predict Lyme incidence from year to year.

Johnson, J.L.; Ginsberg, H.S.; Zhioua, E.; Whitworth, U.G., Jr.; Markowski, D.; Hyland, K.E.; Hu, R.

2004-01-01

372

An experimental study of passive dynamic walking  

Microsoft Academic Search

SUMMARY A two-straight-legged walking mechanism with flat feet is designed and built to study the passive dynamic gait. It is shown that the mechanism having flat feet can exhibit passive dynamic walking as those with curved feet, but the walking efficiency is significantly lower. It is also shown that the balancing mass and its orientation are etfective for controlling side-to-side

Q. Wu; N. Sabet

2004-01-01

373

Passivation designs for CDMA uplink power control  

Microsoft Academic Search

This paper develops new classes of CDMA power control designs by exploiting passivity properties of a gradient-type algorithm proposed in the literature. The new control algorithms offer further design-flexibility, which can be exploited for improved performance and robustness. In our first design, we extend the base station algorithm with Zames-Falb multipliers which preserve its passivity properties. In our second design,

Xingzhe Fan; Murat Arcak; John T. Wen

2004-01-01

374

Passive radio requestable SAW water content sensor  

Microsoft Academic Search

Using a SAW reflective delay line, a new passive sensor for a remote measurement of water content in sandy soil was built. The system operates in the European 434 MHz ISM-band and consists of a request unit and a passive sensor connected by a radio link to the request unit. The SAW device is fabricated on LiNbO3, YZ-cut, and mounted

L. Reindl; C. C. W. Ruppel; A. Kirmayr; N. Slockhausen; M. A. Hilhorst

1999-01-01

375

International comparison of passive solar simulation codes  

SciTech Connect

Two software-software comparisons of passive solar simulation codes have been conducted by the Passive Solar Applications Group of the Committee on the Challenges to Modern Society. These exercises have involved the simulation of hypothetical Trombe wall and direct gain buildings located in Madison, Wisconsin. The countries that have participated in the exercise include Canada, Denmark, France, and the United States. All results available at the time of writing are discussed in this report.

Wray, W.O.

1980-01-01

376

Vertical Diffusivities of Active and Passive Tracers  

NASA Technical Reports Server (NTRS)

The climate models that include a carbon-cycle need the vertical diffusivity of a passive tracer. Since an expression for the latter is not available, it has been common practice to identify it with that of salt. The identification is questionable since T, S are active, not passive tracers. We present the first derivation of the diffusivity of a passive tracer in terms of Ri (Richardson number) and Rq (density ratio, ratio of salinity over temperature z-gradients). The following results have emerged: (a) The passive tracer diffusivity is an algebraic function of Ri, Rq. (b) In doubly stable regimes (DS, partial derivative of T with respect to z > 0, partial derivative of S with respect to z < 0), the passive scalar diffusivity is nearly the same as that of salt/heat for any values of Rq < 0 and Ri > 0. (c) In DC regimes (diffusive convection, partial derivative of T with respect to z < 0, partial derivative of S with respect to z < 0, Rq > 1), the passive scalar diffusivity is larger than that of salt. At Ri = O(1), it can be more than twice as large. (d) In SF regimes (salt fingers, partial derivative of T with respect to z > 0, partial derivative of S with respect to z > 0, Rq < 1), the passive scalar diffusivity is smaller than that of salt. At Ri = O(1), it can be less than half of it. (e) The passive tracer diffusivity predicted at the location of NATRE (North Atlantic Tracer Release Experiment) is discussed. (f) Perhaps the most relevant conclusion is that the common identification of the tracer diffusivity with that of salt is valid only in DS regimes. In the Southern Ocean, where there is the largest CO2 absorption, the dominant regime is diffusive convection discussed in (c) above.

Canuto, V. M.; Cheng, Y.; Howard, A. M.

2010-01-01

377

Passive Safety Features for Small Modular Reactors  

SciTech Connect

The rapid growth in the size and complexity of commercial nuclear power plants in the 1970s spawned an interest in smaller, simpler designs that are inherently or intrinsically safe through the use of passive design features. Several designs were developed, but none were ever built, although some of their passive safety features were incorporated into large commercial plant designs that are being planned or built today. In recent years, several reactor vendors are actively redeveloping small modular reactor (SMR) designs with even greater use of passive features. Several designs incorporate the ultimate in passive safety they completely eliminate specific accident initiators from the design. Other design features help to reduce the likelihood of an accident or help to mitigate the accident s consequences, should one occur. While some passive safety features are common to most SMR designs, irrespective of the coolant technology, other features are specific to water, gas, or liquid-metal cooled SMR designs. The extensive use of passive safety features in SMRs promise to make these plants highly robust, protecting both the general public and the owner/investor. Once demonstrated, these plants should allow nuclear power to be used confidently for a broader range of customers and applications than will be possible with large plants alone.

Ingersoll, Daniel T [ORNL] [ORNL

2010-01-01

378

Passive Tracer Dispersion with Random or Periodic Source  

E-print Network

Passive Tracer Dispersion with Random or Periodic Source Jinqiao Duan Clemson University sources on the pattern formation and long-time behavior of concentration pro- #12;les of passive tracers #12;1 Introduction The dispersion of passive tracers (or passive scalars) occur in various geo

379

Passive Tracer Dispersion with Random or Periodic Source \\Lambda  

E-print Network

Passive Tracer Dispersion with Random or Periodic Source \\Lambda Jinqiao Duan Clemson University sources on the pattern formation and long­time behavior of concentration pro­ files of passive tracers Introduction The dispersion of passive tracers (or passive scalars) occur in various geo­ physical

380

NETWORK-BASED Efficient and Truly Passive MPI-3  

E-print Network

NETWORK-BASED COMPUTING LABORATORY Efficient and Truly Passive MPI-3 RMA Synchronization Using Passive Synchronization Implementations · Efficient and Truly Passive Synchronization scheme · Performance extensions to provide more flexibility 3EuroMPI 2013 #12;NETWORK-BASED COMPUTING LABORATORY MPI-3 RMA Passive

Panda, Dhabaleswar K.

381

Semi-Passive Replication Xavier Defago Andre Schiper Nicole Sergent  

E-print Network

Semi-Passive Replication Xavier D´efago Andr´e Schiper Nicole Sergent D´epartement d This paper presents the semi-passive replication tech- nique ­ a variant of passive replication ­ that can on a primary. Passive replication is a popular replication technique since it can tolerate non

DĂ©fago, Xavier

382

Low-Cost Manufacturable Microchannel Systems for Passive  

E-print Network

Low-Cost Manufacturable Microchannel Systems for Passive PEM Water Management IIPS Number 16910 LowLow--CostCost ManufacturableManufacturable Microchannel Systems for PassiveMicrochannel Systems for Passive PEM Water;2 Project objective: Create a low cost and passive PEM water management system Project objective

383

PRIMA: passive reduced-order interconnect macromodeling algorithm  

Microsoft Academic Search

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

Altan Odabasioglu; Mustafa Celik; Lawrence T. Pileggi

1997-01-01

384

Passive Control Architecture for Virtual Humans Antoine Rennuit, Alain Micaelli,  

E-print Network

Passive Control Architecture for Virtual Humans Antoine Rennuit, Alain Micaelli, Xavier Merlhiot to passivity. We show projections can break passivity, and thus must be used carefully. Our control scheme enables task space and internal control, contact, and joint limits management. Thanks to passivity, it can

Paris-Sud XI, Université de

385

Active and passive learning connections to sleep management  

Microsoft Academic Search

Strong evidence exists that active is more effective than passive learning. In fact, passive learning is more sensitive to sleep debt. Efficiencies for passive learning and passive activities, such as driving, are reduced by more than 50 percent with as little as 18 hours of sleep debt. This relationship obviously affects highway safety. Further, the relationship also affects academic success.

James M. Gregory; Xuepeng Xie; Susan A. Mengel

2003-01-01

386

Washington Correlator  

NASA Technical Reports Server (NTRS)

This report summarizes the activities of the Washington Correlator for 2012. The Washington Correlator provides up to 80 hours of attended processing per week plus up to 40 hours of unattended operation, primarily supporting Earth Orientation and astrometric observations. In 2012, the major programs supported include the IVS-R4, IVS-INT, APSG, and CRF observing sessions.

Hall, David M.; Boboltz, David

2013-01-01

387

Active control of passive acoustic fields: Passive synthetic apertureDoppler beamforming with data from an autonomous  

E-print Network

Active control of passive acoustic fields: Passive synthetic apertureŐDoppler beamforming with data without the use of an active source under control by the receiver. In this passive case, the properties interest. Passive synthetic aperture sonar has no ana- log in the radar community. In contrast

Smith, Jerome A.

388

METHODOLOGY FOR PASSIVE ANALYSIS OF A UNIVERSITY INTERNET LINK / TALK 13 Methodology for Passive Analysis of a University  

E-print Network

METHODOLOGY FOR PASSIVE ANALYSIS OF A UNIVERSITY INTERNET LINK / TALK 13 Methodology for Passive # Abstract--- Passive monitoring of Internet links can e#­ ciently provide valuable data on a wide variety and research questions using our passive measurement methodology. Keywords--- Network Performance Monitoring

California at San Diego, University of

389

Passivity Analysis and Design of Passivity-Based Controllers for Trajectory Tracking at High Speed of Autonomous Vehicles  

E-print Network

Passivity Analysis and Design of Passivity-Based Controllers for Trajectory Tracking at High Speed of passivity between some inputs and outputs, we present design and validation of lateral controllers based is the lateral error displacement. After passivity analysis of the system to establish the properties

Paris-Sud XI, Université de

390

Discreet passive explosive detection through 2-sided wave guided fluorescence  

DOEpatents

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

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

2012-10-16

391

Discreet passive explosive detection through 2-sided waveguided fluorescence  

DOEpatents

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

392

ChemCam Passive Spectroscopy of the Martian Atmosphere  

NASA Astrophysics Data System (ADS)

The design priority of the Laser-Induced Breakdown Spectrometer (LIBS) portion of the ChemCam instrument (Wiens et al. 2012, Space Sci, Rev. 170) on the Mars Science Laboratory (MSL) Curiosity rover is its active mode, which acquires spectra of a laser induced plasma using three spectrometers. However these same spectrometers have excellent sensitivity to ambient light and so are also used independent of the laser in 'passive' mode to acquire spectra of the Martian surface (Johnson et al., 2013, LPSC #1372) and, as we will describe here, the Martian sky. Using ChemCam passive sky observations, we have successfully measured the column abundance of water vapor, molecular oxygen, and carbon dioxide gas, and with further analysis will likely be able to constrain the column abundance of ozone as well as aerosol and cloud particle properties. Although data analysis is ongoing, we currently estimate a 2 sigma precision of < +/- 1 precipitable microns for water vapor, < +/- 30 ppm for molecular oxygen, and < +/- 4 % for carbon dioxide. The three ChemCam spectrometers span 240-342 nm, 382-469 nm, and 474-906 nm, respectively, with a resolution of 0.6 nm FWHM or better. Passive sky observations were obtained on sols 131, 230, and then at regular ~7 sol intervals starting on sol 278. The observation consists of acquiring spectra of light scattered by the atmosphere at two elevation angles so that the ratio of the two resulting radiance spectra yields (after removing the continuum) an extremely precise absorption spectrum with both the solar spectrum and instrument response uncertainties removed. To yield column abundances, the spectra are modeled with a discrete ordinates multiple scattering radiative transfer code that incorporates gas absorption via the correlated-k method.

McConnochie, T. H.; Smith, M. D.; Wolff, M. J.; Bender, S. C.; Johnson, J. R.; Wiens, R. C.; Maurice, S.; Gasnault, O.; Barraclough, B. L.; Blaney, D. L.; DeFlores, L.; Team, M.

2013-12-01

393

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

394

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

395

Passive-solar homes for Texas  

NASA Astrophysics Data System (ADS)

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

Garrison, M. L.

1982-06-01

396

Initial conditions of a simple passive-dynamic walker  

NASA Astrophysics Data System (ADS)

Walking robots hold great potential for the future of military robotics. Their natural agility in rough, unstructured terrain make them ideal for military applications but their power requirements do not. Passive dynamic walkers offer a potentially low-power solution. This class of legged robots utilize the natural inverted pendular dynamics that humans rely on to locomote. The most basic of these systems uses gravity as its power source and has no control system therefore its stability is heavily reliant on its initial conditions. The VICON Motion Capture System was used to record the motions of Coleman and Ruina's1 TinkertoyWalker. The initial angles and angular velocities of the various trials were extracted from the motion capture data and used as inputs to a multi-body dynamics model of the walker. The model was created to provide insight into passive-dynamic walkers and the interactions between the walker and the ground surface. Several trials were performed to quantify the stability space of the experimental walker and improve the correlation of the dynamics model to the physical robot.

Haueisen, Brooke; Hudas, Greg; Hulbert, Greg; Nebel, Kyle

2006-05-01

397

Integrated Source of Spectrally Filtered Correlated Photons for Large-Scale Quantum Photonic Systems  

E-print Network

We demonstrate the generation of quantum-correlated photon pairs combined with the spectral filtering of the pump field by more than 95 dB on a single silicon chip using electrically tunable ring resonators and passive ...

Grassani, Davide

398

Passive Corrosion Behavior of Alloy 22  

SciTech Connect

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

R.B. Rebak; J.H. Payer

2006-01-20

399

Passive Subharmonic Generation Using Memoryless Nonlinear Circuits  

E-print Network

Abstract—A passive subharmonic generation and frequency downconversion method using a memoryless nonlinear circuit coupled to a linear passive resonator is presented. The frequency downconverter can be used to transfer the energy from a high-frequency signal to a lower frequency without requiring any dc power supply. In the synchronous mode, the passive downconverter acts as a self-powered frequency divider. The characteristics of the self-powered frequency downconverter have been studied analytically, and design tradeoffs have been shown for the specific case of a cross-coupled differential pair nonlinearity. As an example, a low-frequency prototype is implemented with discrete components. Analytical results and design procedures are verified in discrete and integrated prototypes. Index Terms—CMOS, frequency conversion, frequency divider, nonlinear circuits, oscillators, subharmonic generation. I.

Zahra Safarian; Student Member; Hossein Hashemi; Senior Member

400

Passive infrared bullet detection and tracking  

DOEpatents

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

Karr, T.J.

1997-01-21

401

Passive infrared bullet detection and tracking  

DOEpatents

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

Karr, Thomas J. (Alamo, CA)

1997-01-01

402

A hybrid active-passive sound absorber  

NASA Astrophysics Data System (ADS)

The structure of an active-passive sound absorber is considered, and issues concerning analytic and experimental studies of the efficiency of sound absorber operation are discussed. A description is presented of both the passive part of the hybrid sound absorber and the active system incorporated in it. A test bench constructed on the basis of a low-frequency acoustic interferometer for measuring the sound absorption coefficient and the input impedance of the hybrid sound absorber under normally incident sound waves is described. An algorithm is proposed for controlling the active system of the hybrid sound absorber. The operation efficiency of the active system controlled by the proposed algorithm is analytically investigated. The results obtained from the experimental study of the hybrid active-passive sound absorber on the measuring test bench are presented.

Belov, V. D.; Migun, Yu. G.; Orlov, A. I.

2012-07-01

403

Passive Cooling System for a Vehicle  

DOEpatents

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

Hendricks, T. J.; Thoensen, T.

2005-11-15

404

Passive cooling system for a vehicle  

DOEpatents

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

Hendricks, Terry Joseph; Thoensen, Thomas

2005-11-15

405

Alternative to Nitric Acid Passivation Project Overview  

NASA Technical Reports Server (NTRS)

The standard practice for protection of stainless steel is a process called passivation. This procedure results in the formation of a metal oxide layer to prevent corrosion. Typical passivation procedures call for the use of nitric acid which exhibits excellent corrosion performance; however, there are a number of environmental, worker safety, and operational issues associated with its use. The longtime military specification for the passivation of stainless steel was cancelled in favor of newer specifications which allow for the use of citric acid in place of nitric acid. Citric acid offers a variety of benefits that include increased safety for personnel, reduced environmental impact, and reduced operational costs. There have been few studies, however, to determine whether citric acid is an acceptable alternative for NASA and DoD. This paper details activities to date including development of the joint test plan, on-going and planned testing, and preliminary results.

Lewis, Pattie L.

2013-01-01

406

Passive infrared bullet detection and tracking  

SciTech Connect

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

Karr, T.J.

1994-12-31

407

The nonlinearity of passive extraocular muscles  

PubMed Central

Passive extraocular muscles (EOMs), like most biological tissues, are hyper-elastic, i.e., their stiffness increases as they are stretched. It has always been assumed, and in a few occasions argued, that this is their only nonlinearity and that it can be ignored in central gaze. However, using novel measurement techniques in anesthetized paralyzed monkeys, we have recently demonstrated that EOMs are characterized by another prominent nonlinearity: the forces induced by sequences of stretches do not sum. Thus, superposition, a central tenet of linear and quasi-linear models, does not hold in passive EOMs. Here, we outline the implications of this finding, especially in light of the common assumption that it is easier for the brain to control a linear than a nonlinear plant. We argue against this common belief: the specific nonlinearity of passive EOMs may actually make it easier for the brain to control the plant than if muscles were linear. PMID:21950971

Quaia, Christian; Ying, Howard S.; Optican, Lance M.

2011-01-01

408

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

409

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.; Lobitz, Donald W.

2003-01-07

410

Passive retrofit handbook: solar applications for residences  

SciTech Connect

Guidance is provided for retrofitting homes with passive solar heating systems. The information presented is kept simple enough to address the homeowner with no technical background. Systems described include direct gain, Trombe wall, and sunspace systems. Information is given which allows the user to make educated decisions about the various factors involved in retrofitting, and the state of the art is presented in the form of simple rule of thumb procedures and building details such that passive solar components can be fashioned using readily available local materials and common hand tools. Many common products are described that go into passive solar systems, with information provided on sizes, weights and other physical properties as well as descriptions, comparative cost guides and lists of the manufacturers. (LEW)

Not Available

1980-01-01

411

Fully Passive Wireless Acquisition of Neuropotentials  

NASA Astrophysics Data System (ADS)

The ability to monitor electrophysiological signals from the sentient brain is requisite to decipher its enormously complex workings and initiate remedial solutions for the vast amount of neurologically-based disorders. Despite immense advancements in creating a variety of instruments to record signals from the brain, the translation of such neurorecording instrumentation to real clinical domains places heavy demands on their safety and reliability, both of which are not entirely portrayed by presently existing implantable recording solutions. In an attempt to lower these barriers, alternative wireless radar backscattering techniques are proposed to render the technical burdens of the implant chip to entirely passive neurorecording processes that transpire in the absence of formal integrated power sources or powering schemes along with any active circuitry. These radar-like wireless backscattering mechanisms are used to conceive of fully passive neurorecording operations of an implantable microsystem. The fully passive device potentially manifests inherent advantages over current wireless implantable and wired recording systems: negligible heat dissipation to reduce risks of brain tissue damage and minimal circuitry for long term reliability as a chronic implant. Fully passive neurorecording operations are realized via intrinsic nonlinear mixing properties of the varactor diode. These mixing and recording operations are directly activated by wirelessly interrogating the fully passive device with a microwave carrier signal. This fundamental carrier signal, acquired by the implant antenna, mixes through the varactor diode along with the internal targeted neuropotential brain signals to produce higher frequency harmonics containing the targeted neuropotential signals. These harmonics are backscattered wirelessly to the external interrogator that retrieves and recovers the original neuropotential brain signal. The passive approach removes the need for internal power sources and may alleviate heat trauma and reliability issues that limit practical implementation of existing implantable neurorecorders.

Schwerdt, Helen N.

412

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

413

Graphical method to analyze dynamic response of passive buildings  

SciTech Connect

Just as the steady state behavior of a building can be understood by adding the UA values of the components, the dynamic behavior can be understood by adding vectors giving the response of the components to driving functions of any given frequency (e.g. the diurnal frequency). The vector addition can be done graphically to obtain an intuitive understanding of the role of each component. The interaction of a component with all the others can be included simply by changing the amplitude and phase of the contribution of the component. Combinations of direct gain and Trombe wall can be analyzed in this manner. Work is underway (a) to correlate the response to diurnal frequency directly to auxiliary energy as well as overheating problems and cooling season performance, and (b) to include other passive systems, movable insulation, etc.

Subbarao, K.; Anderson, J.V.

1981-07-01

414

Passive and active EO sensing close to the sea surface  

NASA Astrophysics Data System (ADS)

The present paper investigates the use of an eye-safe laser rangefinder at 1.5 ?m and TV/IR imaging to obtain information on atmospheric properties at various paths close to the sea surface. On one day active/passive imaging NIR and SWIR systems were also used. The paper will describe the experimental equipment and the results from measurements of atmospheric backscatter as well as TV and IR images of test targets along a 1.8 km path close to the Baltic Sea. The site also contained a weather station and a scintillometer for logging weather and turbulence parameters. Results correlating the lidar attenuation with the imaging performance will be given and compared with models.

Steinvall, Ove; Persson, Rolf; Berglund, Folke; Öhgren, Johan; Gustafsson, Frank

2014-10-01

415

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

416

The passive diffusion of Leptospira interrogans  

E-print Network

Motivated by recent experimental measurements, the passive diffusion of the bacterium \\textit{Leptospira interrogans} is investigated theoretically. By approximating the cell shape as a straight helix and using the slender-body-theory approximation of Stokesian hydrodynamics, the resistance matrix of \\textit{Leptospira} is first determined numerically. The passive diffusion of the helical cell is then obtained computationally using a Langevin formulation which is sampled in time in a manner consistent with the experimental procedure. Our results are in excellent quantitative agreement with the experimental results with no adjustable parameters.

Lyndon Koens; Eric Lauga

2014-11-20

417

The passive diffusion of Leptospira interrogans  

NASA Astrophysics Data System (ADS)

Motivated by recent experimental measurements, the passive diffusion of the bacterium Leptospira interrogans is investigated theoretically. By approximating the cell shape as a straight helix and using the slender-body-theory approximation of Stokesian hydrodynamics, the resistance matrix of Leptospira is first determined numerically. The passive diffusion of the helical cell is then obtained computationally using a Langevin formulation which is sampled in time in a manner consistent with the experimental procedure. Our results are in excellent quantitative agreement with the experimental results with no adjustable parameters.

Koens, Lyndon; Lauga, Eric

2014-12-01

418

An all-silicon passive optical diode.  

PubMed

A passive optical diode effect would be useful for on-chip optical information processing but has been difficult to achieve. Using a method based on optical nonlinearity, we demonstrate a forward-backward transmission ratio of up to 28 decibels within telecommunication wavelengths. Our device, which uses two silicon rings 5 micrometers in radius, is passive yet maintains optical nonreciprocity for a broad range of input power levels, and it performs equally well even if the backward input power is higher than the forward input. The silicon optical diode is ultracompact and is compatible with current complementary metal-oxide semiconductor processing. PMID:22194410

Fan, Li; Wang, Jian; Varghese, Leo T; Shen, Hao; Niu, Ben; Xuan, Yi; Weiner, Andrew M; Qi, Minghao

2012-01-27

419

The passive diffusion of Leptospira interrogans.  

PubMed

Motivated by recent experimental measurements, the passive diffusion of the bacterium Leptospira interrogans is investigated theoretically. By approximating the cell shape as a straight helix and using the slender-body-theory approximation of Stokesian hydrodynamics, the resistance matrix of Leptospira is first determined numerically. The passive diffusion of the helical cell is then obtained computationally using a Langevin formulation which is sampled in time in a manner consistent with the experimental procedure. Our results are in excellent quantitative agreement with the experimental results with no adjustable parameters. PMID:25426593

Koens, Lyndon; Lauga, Eric

2014-12-01

420

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

421

Passive obstacle location for rotorcraft guidance  

NASA Technical Reports Server (NTRS)

Nap-of-the-earth flight mode is extremely demanding on the rotorcraft pilots. This fact has motivated the research in automating various components of low altitude rotorcraft flight operations. Concurrent with the development of guidance laws, efforts are under way to develop systems for locating the terrain and the obstacles using inputs from passive electrooptical sensors such as TV cameras and infrared imagers. A passive obstable location algorithm that uses image sequences from cameras undergoing translational and rotational motion is developed. The algorithm is in a general form and can operate in multicamera imaging environments. Performance results using an image sequence from an airborne camera are given.

Menon, P. K. A.; Chatterji, G. B.; Sridhar, B.

1991-01-01

422

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

423

Robust Control of Non-Passive Systems via Passification  

NASA Technical Reports Server (NTRS)

This paper presents methods which enable the use of passivity-based control design techniques to control non-passive systems. For inherently non-passive finite- dimensional linear time-invaraint systems, passification methods are presented to render such systems passive by suitable compensation. The passified system can then be controlled by a class of passive linear controllers. The idea is to exploit the robust stability properties of passivity-based control laws for uncertain systems. The proposed passification methods are demonstrated by application to the ACC benchmark problem and to pitch-axis control of an F-18 High Alpha Research Vehicle (HARV) model.

Kelkar, A. G.; Joshi, S. M.

1997-01-01

424

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

425

Physical Factors Influencing Pleasant Touch during Passive Fingertip Stimulation  

PubMed Central

Objective Tactile explorations with the fingertips provide information regarding the physical properties of surfaces and their relative pleasantness. Previously, we performed an investigation in the active touch domain and linked several surface properties (i.e. frictional force fluctuations and net friction) with their pleasantness levels. The aim of the present study was to investigate physical factors being important for pleasantness perception during passive fingertip stimulation. Specifically we were interested to see whether factors, such as surfaces' topographies or their frictional characteristics could influence pleasantness. Furthermore, we ascertained how the stimulus pleasantness level was impacted by (i) the normal force of stimulus application (FN) and (ii) the stimulus temperature (TS). Methods and Results The right index fingertips of 22 blindfolded participants were stimulated using 27 different stimuli, which varied in average roughness (Ra) and TS. A 4-axis robot moved the stimuli horizontally under participants' fingertips with three levels of FN. The robot was equipped with force sensors, which recorded the FN and friction force (FT) during stimulation. Participants rated each stimulus according to a three-level pleasantness scale, as very pleasant (scored 0), pleasant (scored 1), or unpleasant (scored 2). These ordinal pleasantness ratings were logarithmically transformed into linear and unidimensional pleasantness measures with the Rasch model. Statistical analyses were conducted to investigate a possible link between the stimulus properties (i.e. Ra, FN, FT, and TS) and their respective pleasantness levels. Only the mean Ra and FT values were negatively correlated with pleasantness. No significant correlation was detected between FN or TS and pleasantness. Conclusion Pleasantness perception, resulting from passive fingertip stimulation, seems to be influenced by the surfaces' average roughness levels and average FT occurring during fingertip stimulation. PMID:25000561

Klöcker, Anne; Oddo, Calogero Maria; Camboni, Domenico; Penta, Massimo; Thonnard, Jean-Louis

2014-01-01

426

Passive solar design handbook. Volume two of two volumes: passive solar design analysis  

SciTech Connect

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

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

1980-01-01

427

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

428

Space radiation effects on erbium-doped fiber devices: sources, amplifiers, and passive measurements  

Microsoft Academic Search

Measurements have been made of the effect of ?-irradiation on the performance of active erbium-doped fiber devices. These include the decrease in optical power of an erbium-doped fiber amplifier (EDFA) and a superluminescent source (SLS), and the shift in centroid wavelength of the SLS with exposure. Calculations have been performed to correlate these effects with the radiation-induced absorption measured passively.

G. M. Williams; E. J. Friebele

1997-01-01

429

Range sidelobes reduction filters for WiFi-based passive bistatic radar  

Microsoft Academic Search

In this paper the feasibility of a WiFi transmissions based passive bistatic radar is analysed. The auto-correlation function of this waveform of opportunity is characterized with reference to typical signals broadcasted by a 802.11 access point and it is shown to yield a high sidelobe level which strongly limits the useful dynamic range. Proper weighting networks are proposed to cope

Paolo Falcone; Fabiola Colone; Pierfrancesco Lombardo; Tullio Bucciarelli

2009-01-01

430

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

431

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...

432

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...

433

The Self-Report Psychopathy Scale and Passive Avoidance LearningA Validation Study of Race and Gender Effects  

Microsoft Academic Search

The reliability and validity of the Self-Report Psychopathy Scale (SRPS) was examined in a noninstitutionalized offender sample of mixed gender and race. Adequate alpha coefficients were obtained for the total sample and across gender and race. The SRPS was compared to measures of trait anxiety and passive avoidance errors. SRPS total, primary, and secondary scores were positively and significantly correlated

Monica K. Epstein; Norman G. Poythress; Karen O. Brandon

2006-01-01

434

Comparison of passive microwave and modeled estimates of total watershed SWE in the continental United States  

NASA Astrophysics Data System (ADS)

In the U.S., a dedicated system of snow measurement stations and snowpack modeling products is available to estimate the snow water equivalent (SWE) throughout the winter season. In other regions of the world that depend on snowmelt for water resources, snow data can be scarce, and these regions are vulnerable to drought or flood conditions. Even in the U.S., water resource management is hampered by limited snow data in certain regions, as evident by the 2011 Missouri Basin flooding due in large part to the significant Plains snowpack. Satellite data could potentially provide important information in under-sampled areas. This study compared the daily AMSR-E and SSM/I SWE products over nine winter seasons to spatially distributed, modeled output SNODAS summed over 2100 watersheds in the conterminous U.S. Results show large areas where the passive microwave retrievals are highly correlated to the SNODAS data, particularly in the northern Great Plains and southern Rocky Mountain regions. However, the passive microwave SWE is significantly lower than SNODAS in heavily forested areas, and regions that typically receive a deep snowpack. The best correlations are associated with basins in which maximum annual SWE is less than 200 mm, and forest fraction is less than 20%. Even in many watersheds with poor correlations between the passive microwave data and SNODAS maximum annual SWE values, the overall pattern of accumulation and ablation did show good agreement and therefore may provide useful hydrologic information on melt timing and season length.

Vuyovich, Carrie M.; Jacobs, Jennifer M.; Daly, Steven F.

2014-11-01

435

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

436

Correlative Tomography  

PubMed Central

Increasingly researchers are looking to bring together perspectives across multiple scales, or to combine insights from different techniques, for the same region of interest. To this end, correlative microscopy has already yielded substantial new insights in two dimensions (2D). Here we develop correlative tomography where the correlative task is somewhat more challenging because the volume of interest is typically hidden beneath the sample surface. We have threaded together x-ray computed tomography, serial section FIB-SEM tomography, electron backscatter diffraction and finally TEM elemental analysis all for the same 3D region. This has allowed observation of the competition between pitting corrosion and intergranular corrosion at multiple scales revealing the structural hierarchy, crystallography and chemistry of veiled corrosion pits in stainless steel. With automated correlative workflows and co-visualization of the multi-scale or multi-modal datasets the technique promises to provide insights across biological, geological and materials science that are impossible using either individual or multiple uncorrelated techniques. PMID:24736640

Burnett, T. L.; McDonald, S. A.; Gholinia, A.; Geurts, R.; Janus, M.; Slater, T.; Haigh, S. J.; Ornek, C.; Almuaili, F.; Engelberg, D. L.; Thompson, G. E.; Withers, P. J.

2014-01-01

437

Correlation Correlogram  

E-print Network

Network Correlation Neural Oscillator Correlogram CrossHair cell Cochlear Filtering Signal oscillator is combination of raw input (Ir - based on segments), global inhibition and network activity oscillators is active, all others are suppressed; i.e. only one group can be active at any one time. Io Ir Wz

Wrigley, Stuart

438

Ambient stability of chemically passivated germanium interfaces  

E-print Network

Parkman ave., Pittsburgh, PA 15260, USA Received 18 March 2003; accepted for publication 15 July 2003-terminations are more robust, showing little sign of oxide formation after a month in ambient. Ă? 2003 Elsevier B.V. All; Silicon; Sulphides; Single crystal surfaces 1. Introduction The formation of a stable passivating layer

Borguet, Eric

439

Comprehension of Passives in Broca's Aphasia  

ERIC Educational Resources Information Center

Drai and Grodzinsky have statistically analyzed a large corpus of data on the comprehension of passives by patients with Broca's aphasia. The data come, according to Drai and Grodzinsky, from binary choice tasks. Among the languages that are analyzed are Dutch and German. Drai and Grodzinsky argue that Dutch and German speaking Broca patients…

Bastiaanse, Roelien; van Zonneveld, Ron

2006-01-01

440

Passive dynamic walking model with upper body  

Microsoft Academic Search

SUMMARY This paper presents the simplest walking model with an upper body. The model is a passive dynamic walker, i.e. it walks down a slope without motor input or control. The upper body is confined to the midway angle of the two legs. With this kinematic constraint, the model has only two degrees of freedom. The model achieves surprisingly successful

Martijn Wisse; Arend L. Schwab; Frans C. T. Van Der Helm

2004-01-01

441

Axisymmetric Jet Control Using Passive Grids  

Microsoft Academic Search

The structure of a circular jet, modified by placing grids of two different configurations near the nozzle exit plane, was investigated by using a single hot wire probe. An annular grid which perturbed mainly the axisymmetric shear layer and a circular disk grid which covered most of the potential core were used to modify the jet passively. Behind the annular

R. Lehman; S. Rajagopalan; P. Burattini; R. A. Antonia

442

Defeating Passive Eavesdropping with Quantum Illumination  

E-print Network

Quantum illumination permits Alice and Bob to communicate at 50 Mbit/s over 50 km of low-loss fiber with error probability less than 10^(-6) while the optimum passive eavesdropper's error probability must exceed 0.28.

Jeffrey H. Shapiro

2009-04-28

443

Algorithms for passive compliance mechanism design  

Microsoft Academic Search

In this article the authors study the spatial stiffness of passive compliance mechanisms. The mechanisms under consideration are characterized by the 6 by 6 spatial stiffness matrix. Several algorithms for realizations of spatial stiffness matrices are examined. The stiffness constants of the realization are related to the eigenvalues of the linear force portion of the stiffness matrix. Finally, a new

Rodney G. Roberts; Theresa A. Shirey

2003-01-01

444

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

445

OBSERVATIONS OF LAND SURFACE PASSIVE MICROWAVE POLARIMETRY  

Technology Transfer Automated Retrieval System (TEKTRAN)

The launch of WindSat and potential designs of future operational passive microwave sensors such as Conical Scanning Microwave Imager/Scanner (CMIS) have prompted an examination of what additional information about land surface features may be present in the 3rd and 4th Stokes parameters beyond the ...

446

Passive vibration control via electromagnetic shunt damping  

Microsoft Academic Search

This work will present a new type of passive vibration control technique based on the concept of electromagnetic shunt damping. The proposed technique is similar to piezoelectric shunt damping, as an appropriately designed impedance is shunted across the terminals of the transducer. Theoretical and experimental results are presented for a simple electromagnetic mass spring damper system.

Sam Behrens; Andrew J. Fleming; S. O. Reza Moheimani

2005-01-01

447

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

448

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

449

Passive and active Reconfigurable antenna design  

E-print Network

Passive and active Reconfigurable antenna design Doctoral course ­ Ulm, Germany - October 8-12 2012 for reconfigurable antennas (Software defined radio; Cognitive radio; Other needs including defence and space surface mount, LTCC) - MMIC introduction and design flow - MMIC in antenna applications: system aspects

Pfeifer, Holger

450

Passive safety injection system using borated water  

SciTech Connect

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

451

Passive booster for pumping liquified gases  

Microsoft Academic Search

The present invention comprises a method and apparatus for maintaining a liquified gas such as COâ or Nâ in a liquid state prior to its introduction into the suction of a positive displacement pump such as is commonly employed in high pressure well stimulation work in the petroleum industry. A heat exchanger, preferably referred to as a passive booster, is

Hamid

1984-01-01

452

Crystalline passive shutter for iodine lasers  

NASA Astrophysics Data System (ADS)

Results of the investigations of the new passive shutter on the base of yttrium-aluminum garnet activated by vanadium ions (V3+) are presented. Wide absorption band (1.2 - 1.4 (mu) ) with maximum on the wavelength 1.34 (mu) corresponds to the electron-vibration transition 3A2 - 3T2 of ions V3+.

Grenishin, A. S.; Kiselev, V. M.; Krutova, L. I.; Lukin, Alexandre V.; Sandulenko, V. A.

1994-08-01

453

Analysis of passive solar thermal energy storage  

Microsoft Academic Search

This paper describes a study of the effects of energy storage by phase change materials (PCMs) on the thermal performance of a simple, one-room passive solar building. It was found that in direct gain applications, the PCM melting temperature was the thermophysical parameter that most directly affected the building heating load. The relative influence of PCM thickness, thermal conductivity, location,

J. J. Tomlinson; G. A. Geist; M. D. Morris

1984-01-01

454

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

455

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

456

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

457

Efficient Object Identification with Passive RFID Tags  

Microsoft Academic Search

Radio frequency identification systems with passive tags are power- ful tools for object identification. However, if multiple tags are to be identified simultaneously, messages from the tags can collide and cancel each other out. Therefore, multiple read cycles have to be performed in order to achieve a high recognition rate. For a typical stochastic anti-collision scheme, we show how to

Harald Vogt

2002-01-01

458

Multiple object identification with passive RFID tags  

Microsoft Academic Search

We investigate the applicability of passive RFID systems to the task of identifying multiple tagged objects simultaneously, assuming that the number of tags is not known in advance. We present a combinatorial model of the communication mechanism between the reader device and the tags, and use this model to derive the optimal parameter setting for the reading process, based on

Harald Vogt

2002-01-01

459

Passive acoustic analysis of complex bubbly flows  

Microsoft Academic Search

A technique for extracting data from a complex bubbly flow is reviewed, beginning with fundamental laboratory and theoretical developments of the method and ending with an illustration of the technique in practice. Passive bubble acoustics involves 'listening' to the sounds naturally emitted by bubbles and exploiting these data to infer properties of the system. In many industrial plants, the multiphase

Richard Manasseh

2004-01-01

460

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

461

Passive modal damping with piezoelectric shunts  

Microsoft Academic Search

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

John J. Granier; R. Jason Hundhausen; Gabriel E. Gaytan

2001-01-01

462

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

463

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.

464

Multiple finger, passive adaptive grasp prosthetic hand  

Microsoft Academic Search

This paper describes the mechanical features of an experimental, multiple finger, prosthetic hand which has been designed for children in the 7–11 year age group. Conventional prosthetic hands exist for this age group, but they have limited mechanical function. The experimental hand presented is able to perform passive adaptive grasp, that is, the ability of the fingers to conform to

N Dechev; W