Note: This page contains sample records for the topic passive gene-environment correlation from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
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.

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 Central

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.

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

2014-01-01

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.

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.

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

2010-01-01

7

Gene–environment interdependence  

Microsoft Academic Search

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

Michael Rutter

2012-01-01

8

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.

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

2013-01-01

9

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

PubMed

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 Study of lead exposure, iron metabolism genes, and birth weight. PMID:21955029

Sánchez, Brisa N; Kang, Shan; Mukherjee, Bhramar

2012-06-01

10

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.

KLAHR, ASHLEA M.; THOMAS, KATHERINE M.; HOPWOOD, CHRISTOPHER J.; KLUMP, KELLY L.; BURT, S. ALEXANDRA

2014-01-01

11

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.

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

2013-01-01

12

Passive imaging using cross correlations of ambient noise signals  

Microsoft Academic Search

It is possible to estimate the travel time or even the full Green's function between two passive sensors from the cross correlation of recorded signal amplitudes generated by ambient noise sources. Using the stationary phase method we show that it is possible to image reflectors buried in a smoothly varying medium by migrating the cross correlations of the noise signals.

Josselin Garnier; George Papanicolaou

2009-01-01

13

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

PubMed 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.

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

2012-01-01

14

Correlation based testing for passive sonar picture rationalization  

Microsoft Academic Search

Modern passive sonar systems employ a high degree of automation to produce a track-level sonar picture. Further refinement of the track-level information is normally performed by a human operator. Providing automated assistance would reduce the operator's workload and is a key enabler for semi- and fully automated sonar systems. The nature of the signals emitted by targets and of the

Garfield R. Mellema

2007-01-01

15

Correlation of passivity symptoms and dysfunctional visuomotor action monitoring in psychosis  

PubMed Central

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

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

2008-01-01

16

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

17

3D passive photon counting automatic target recognition using advanced correlation filters.  

PubMed

In this Letter, we present results for detecting and recognizing 3D objects in photon counting images using integral imaging with maximum average correlation height filters. We show that even under photon starved conditions objects may be automatically recognized in passively sensed 3D images using advanced correlation filters. We show that the proposed filter synthesized with ideal training images can detect and recognize a 3D object in photon counting images, even in the presence of occlusions and obscuration. PMID:21403709

Cho, Myungjin; Mahalanobis, Abhijit; Javidi, Bahram

2011-03-15

18

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

19

Correlation between mechanomyography features and passive movements in healthy and paraplegic subjects.  

PubMed

Mechanomyography (MMG) measures both muscular contraction and stretching activities and can be used as feedback in the control of neuroprostheses with Functional Electrical Stimulation (FES). In this study we evaluated the correlation between MMG features and passive knee angular movement of rectus femoris and vastus lateralis muscles acquired from healthy volunteers (HV) and spinal cord injured volunteers (SCIV). Twelve HV and thirteen SCIV were submitted to passive and FES elicited knee extensions and in each extension, eleven windows of analysis with 0.5s length were inspected. Temporal (RMS and INT) and frequency (MF and ?3) features were extracted. Spearman correlation coefficients (p) were computed in order to check correlations between the features obtained from both MMG sensors. The correlation between MMG(MF) and MMG temporal analysis (RMS and INT) to HV was classified as positive, moderate (p from 0.635 to 0.681) and high (p from 0.859 to 0.870), and weak (positive e negative) to SCIV. These results differ from those obtained in voluntary contraction or artificially evoked by functional electrical stimulation and may be relevant in applications with closed loop control systems. PMID:22256010

Krueger, Eddy; Scheeren, Eduardo M; Nogueira-Neto, Guilherme N; da S N Button, Vera Lúcia; Nohama, Percy

2011-01-01

20

Gene-environment interactions in asthma  

PubMed Central

The underlying pathogenesis of asthma, one of the most common chronic diseases of childhood, is not fully understood. There is a well?documented heritable component to this disease and environmental factors associated with a Westernised lifestyle have also been implicated; recent studies suggest gene–environment interactions are important in the development of this disease. In the absence of a previous review in children, the present report presents the accumulating evidence for gene–environment interactions in asthma pathogenesis. Studies of these interactions in different populations have yielded both expected and unexpected results. This is a new and rapidly developing field where there are currently many more questions than answers.

McLeish, S; Turner, S W

2007-01-01

21

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.

22

Biological Implications of Gene-Environment Interaction  

ERIC Educational Resources Information Center

Gene-environment interaction (G x E) has been treated as both a statistical phenomenon and a biological reality. It is argued that, although there are important statistical issues that need to be considered, the focus has to be on the biological implications of G x E. Four reports of G x E deriving from the Dunedin longitudinal study are used as…

Rutter, Michael

2008-01-01

23

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.

24

DIRECTIVITY PATTERNS OF THE TRANSDUCERS FOR THE CORRELATIVE PASSIVE ACOUSTIC THERMOTOMOGRAPHY 1 Scientific Research Centre of Electronic Diagnostic Systems \\  

Microsoft Academic Search

Passive acoustic thermotomography is a method of reconstructio n of 2-D and 3-D distributions of temperature at the depth of any objects. The method is based on measurements of intrinsic thermal acoustic radiation of the investigated object. Directivity patterns of two piezotransducers (PTs) for measurement of the spatial correlation function of the sound pressure generated by a source of the

V. I. Passechnik; A. A. Anosov; Yu. N. Barabanenkov; L. R. Gavrilov

25

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

ERIC Educational Resources Information Center

This study investigates possible individual and class correlates of defending and passive bystanding behavior in bullying, in a sample of 1,825 Italian primary school (mean age = 10 years 1 month) and middle school (mean age = 13 years 2 months) students. The findings of a series of multilevel regression models show that both individual (e.g.,…

Pozzoli, Tiziana; Gini, Gianluca; Vieno, Alessio

2012-01-01

26

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

27

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

Microsoft Academic Search

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

Dirk Leube; Carin Whitney; Tilo Kircher

2008-01-01

28

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

29

Correlation between composition of passive layer and corrosion behavior of high Si-containing austenitic stainless steels in nitric acid  

NASA Astrophysics Data System (ADS)

Austenitic stainless steels with 18% Cr have a good corrosion behavior in pure nitric acid. However, when oxidizing power of the solution increases, this kind of stainless steels faces a severe intergranular corrosion. Adding a sufficiently high concentration of silicon to the steel avoids this type of corrosion: in oxidizing solutions, those stainless steels exhibit generalized corrosion but their dissolution rate is higher than the one of stainless steels without silicon. To find out the role of silicon on such effects, the corrosion behavior of two different stainless steels with equivalent chromium content but with different silicon content (304L steel and Uranus S1N) has been studied in concentrated nitric acid solutions. Correlations have been evidenced between the passive layer composition investigated by XPS analysis and the corrosion behavior characterized by electrochemical techniques. The presence of silicon in the steel changes neither the oxidation state of chromium or iron, nor the ratio between iron and chromium in the passive layer. Silicon is present in the passive layer in an important content (35 at.%) and thus decreases the chromium content of the passive layer (80 and 50 at.% respectively for 304L steel and Uranus S1N after nitric passivation). Uranus S1N exhibits a less protective passive layer and so its generalized corrosion rate is higher than the one of 304L steel. A selective deposition of platinoïds highlights differences of polarization distribution on the surface between the grain boundaries and grain faces for theses steels. For Uranus S1N, the similar electrochemical behavior of grain boundaries and faces might be connected with the homogeneous silicon distribution.

Robin, R.; Miserque, F.; Spagnol, V.

2008-03-01

30

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

PubMed Central

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

Ober, Carole; Vercelli, Donata

2010-01-01

31

Animal models of gene-environment interactions in schizophrenia  

PubMed Central

The pathogenesis of schizophrenia and related mental illnesses likely involves multiple interactions between susceptibility genes of small effects and environmental factors. Gene-environment interactions occur across different stages of neurodevelopment to produce heterogeneous clinical and pathological manifestations of the disease. The main obstacle for mechanistic studies of gene-environment interplay has been the paucity of appropriate experimental systems for elucidating the molecular pathways that mediate gene-environment interactions relevant to schizophrenia. Recent advances in psychiatric genetics and a plethora of experimental data from animal studies allow us to suggest a new approach to gene-environment interactions in schizophrenia. We propose that animal models based on identified genetic mutations and measurable environment factors will help advance studies of the molecular mechanisms of gene-environment interplay.

Ayhan, Yavuz; Sawa, Akira; Ross, Christopher A.; Pletnikov, Mikhail V.

2009-01-01

32

Gene-environment interactions in obesity.  

PubMed

Obesity is a global and growing problem. The detrimental health consequences of obesity are significant and include co-morbidities such as diabetes, cancer and coronary heart disease. The marked rise in obesity observed over the last three decades suggests that behavioural and environmental factors underpin the chronic mismatch between energy intake and energy expenditure. However, not all individuals become obese, suggesting that there is considerable variation in responsiveness to 'obesogenic' environments. Some individuals defend easily against a propensity to accumulate fat mass and become overweight whilst others are predisposed to gain weight, possibly as a function of genotype. The genetic contribution to obesity is well established. Common obesity is polygenic, involving complex gene-gene and gene-environment interactions, and it is these interactions that produce the multi-factorial obese phenotypes. Candidate gene variants for polygenic obesity appear to disrupt pathways involved in the regulation of energy intake and expenditure and include adrenergic receptors, uncoupling proteins, PPARG, POMC, MC4R and a set of single nucleotide polymorphisms in the FTO locus. Notably, the FTO gene is the most robust gene for common obesity characterised to date, and recent data shows that the FTO locus seems to confer risk of obesity through increasing energy intake and reduced satiety. Gene variants involved in pathways regulating addiction and reward behaviours may also play a role in predisposition to obesity. Understanding the routes through which the genotype is expressed will ultimately provide opportunities for developing strategies to intervene, as the interaction between genotype and environment is potentially modifiable through behaviour change. PMID:19955787

Hetherington, Marion M; Cecil, Joanne E

2010-01-01

33

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

PubMed

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

Pozzoli, Tiziana; Gini, Gianluca; Vieno, Alessio

2012-11-01

34

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

National Technical Information Service (NTIS)

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

J. R. Piepmeier

2003-01-01

35

Green's Function Retrieval and Passive Imaging from Correlations of Wideband Thermal Radiations  

NASA Astrophysics Data System (ADS)

We present an experimental demonstration of electromagnetic Green’s function retrieval from thermal radiations in anechoic and reverberant cavities. The Green’s function between two antennas is estimated by cross correlating milliseconds of decimeter noise. We show that the temperature dependence of the cross-correlation amplitude is well predicted by the blackbody theory in the Rayleigh-Jeans limit. The effect of a nonuniform temperature distribution on the cross-correlation time symmetry is also explored. Finally, we open a new way to image scatterers using ambient thermal radiations.

Davy, Matthieu; Fink, Mathias; de Rosny, Julien

2013-05-01

36

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

NASA Technical Reports Server (NTRS)

Four calibration algorithms are studied for microwave polarimeters that use hybrid coupler-based correlators: 1) conventional two-look of hot and cold sources, 2) three looks of hot and cold source combinations, 3) two-look with correlated source, and 4) four-look combining methods 2 and 3. The systematic errors are found to depend on the polarimeter component parameters and accuracy of calibration noise temperatures. A case study radiometer in four different remote sensing scenarios was considered in light of these results. Applications for Ocean surface salinity, Ocean surface winds, and soil moisture were found to be sensitive to different systematic errors. Finally, a standard uncertainty analysis was performed on the four-look calibration algorithm, which was found to be most sensitive to the correlated calibration source.

Piepmeier, J. R.

2003-01-01

37

Passive cable properties and morphological correlates of neurones in the lateral geniculate nucleus of the cat.  

PubMed

1. We used an in vivo preparation of the cat to study the passive cable properties of sixteen X and twelve Y cells in the lateral geniculate nucleus. Cells were modelled as equivalent cylinders according to Rall's formulations (Rall, 1959a, 1969, 1977). We injected intracellular current pulses into these geniculate neurones, and we analysed the resulting voltage transients to obtain the cable parameters of these cells. In addition, fifty-four physiologically characterized neurones were labelled with horseradish peroxidase (HRP) and analysed morphologically. 2. Analysis of HRP-labelled geniculate neurones showed that the dendritic branching pattern of these cells adheres closely to the 3/2 power rule. That is, at each branch point, the diameter of the parent branch raised to the 3/2 power equals the sum of the diameters of the daughter dendrites after each is raised to the 3/2 power. Furthermore, preliminary data indicate that the dendritic terminations emanating from each primary dendrite occur at the same electrotonic distance from the soma. These observations suggest that both X and Y cells meet the geometric constraints necessary for reduction of their dendritic arbors into equivalent cylinders. 3. We found a strong linear relationship between the diameter of each primary dendrite and the membrane surface area of the arbor emanating from it. We used this relationship to derive an algorithm for determining the total somatic and dendritic membrane surface area of an X and Y cell simply from knowledge of the diameters of its soma and primary dendrites. 4. Both geniculate X and Y cells display current-voltage relationships that were linear within +/- 20 mV of the resting membrane potential. This meant that we could easily remain within the linear voltage range during the voltage transient analyses. 5. X and Y cells clearly differ in terms of many of their electrical properties, including input resistance, membrane time constant and electrotonic length. The difference in input resistance between X and Y cells cannot be attributed solely to the smaller average size of X cells, but it also reflects a higher specific membrane resistance (Rm) of the X cells. Furthermore, X cells exhibit electrotonic lengths slightly larger than those of Y cells, but both neuronal types display electrotonic lengths of roughly 1. This indicates that even the most distally located innervation to these cells should have considerable influence on their somatic and axonal responses.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3309260

Bloomfield, S A; Hamos, J E; Sherman, S M

1987-02-01

38

Understanding risk for psychopathology through imaging gene-environment interactions  

PubMed Central

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

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

2011-01-01

39

Gene-Environment Contributions to Young Adult Sexual Partnering  

Microsoft Academic Search

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

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

2007-01-01

40

Eating disorders, gene–environment interactions and epigenetics  

Microsoft Academic Search

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

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

2011-01-01

41

Correlation between passive film-induced stress and stress corrosion cracking of ?-Ti in a methanol solution at various potentials  

Microsoft Academic Search

The flow stress of a specimen of ?-Ti before unloading is different with the yield stress of the same specimen after unloading and forming a passive film through immersing in a methanol solution at various constant potentials. The difference is the passive film-induced stress. The film-induced stress and susceptibility to stress corrosion cracking (SCC) in the methanol solution at various

X. Z Guo; K. W Gao; W. Y Chu; L. J Qiao

2003-01-01

42

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.

Uher, Rudolf

2014-01-01

43

Gene-environment interactions in severe mental illness.  

PubMed

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

44

Gene-Environment Interaction in Yeast Gene Expression  

PubMed Central

The effects of genetic variants on phenotypic traits often depend on environmental and physiological conditions, but such gene–environment interactions are poorly understood. Recently developed approaches that treat transcript abundances of thousands of genes as quantitative traits offer the opportunity to broadly characterize the architecture of gene–environment interactions. We examined the genetic and molecular basis of variation in gene expression between two yeast strains (BY and RM) grown in two different conditions (glucose and ethanol as carbon sources). We observed that most transcripts vary by strain and condition, with 2,996, 3,448, and 2,037 transcripts showing significant strain, condition, and strain–condition interaction effects, respectively. We expression profiled over 100 segregants derived from a cross between BY and RM in both growth conditions, and identified 1,555 linkages for 1,382 transcripts that show significant gene–environment interaction. At the locus level, local linkages, which usually correspond to polymorphisms in cis-regulatory elements, tend to be more stable across conditions, such that they are more likely to show the same effect or the same direction of effect across conditions. Distant linkages, which usually correspond to polymorphisms influencing trans-acting factors, are more condition-dependent, and often show effects in different directions in the two conditions. We characterized a locus that influences expression of many growth-related transcripts, and showed that the majority of the variation is explained by polymorphism in the gene IRA2. The RM allele of IRA2 appears to inhibit Ras/PKA signaling more strongly than the BY allele, and has undergone a change in selective pressure. Our results provide a broad overview of the genetic architecture of gene–environment interactions, as well as a detailed molecular example, and lead to key insights into how the effects of different classes of regulatory variants are modulated by the environment. These observations will guide the design of studies aimed at understanding the genetic basis of complex traits.

Smith, Erin N; Kruglyak, Leonid

2008-01-01

45

A novel gene-environment interaction involved in endometriosis  

PubMed Central

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

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

2011-01-01

46

Gene-Environment-Wide Association Studies: Emerging Approaches  

PubMed Central

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

Thomas, Duncan

2010-01-01

47

Risk, Resilience, and Gene-Environment Interplay in Primates  

PubMed Central

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

Suomi, Stephen J.

2011-01-01

48

Correlation between carrier mobility of pentacene thin-film transistor and surface passivation of its gate dielectric  

SciTech Connect

The carrier mobility of pentacene thin-film transistor is studied by passivating the surface of its SiO{sub 2} gate dielectric in NH{sub 3} at different temperatures, namely, 900, 1000, 1100, and 1150 deg. C. Measurements demonstrate that the higher the annealing temperature, the higher the carrier mobility of the OTFT is. The device annealed at 1150 deg. C has a field-effect mobility of 0.74 cm{sup 2}/V s, which is 35% higher than that of the device annealed at 900 deg. C. Energy-dispersive x-ray analysis, scanning-electron microscopy, and atomic-force microscopy show that the higher carrier mobility should be due to more nitrogen incorporated at the gate-dielectric surface which results in more passivated dielectric surface and larger pentacene grains for carrier transport.

Cheng, Kam Ho; Tang, Wing Man; Deng, L. F.; Leung, C. H.; Lai, P. T. [Department of Electrical and Electronic Engineering, University of Hong Kong, Pokfulam Road (Hong Kong); Che Chiming [Department of Chemistry, The University of Hong Kong, Pokfulam Road (Hong Kong)

2008-12-01

49

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

PubMed

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

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

2013-02-01

50

Gene-gene and gene-environment interactions in ulcerative colitis.  

PubMed

Genome-wide association studies (GWAS) have identified at least 133 ulcerative colitis (UC) associated loci. The role of genetic factors in clinical practice is not clearly defined. The relevance of genetic variants to disease pathogenesis is still uncertain because of not characterized gene-gene and gene-environment interactions. We examined the predictive value of combining the 133 UC risk loci with genetic interactions in an ongoing inflammatory bowel disease (IBD) GWAS. The Wellcome Trust Case-Control Consortium (WTCCC) IBD GWAS was used as a replication cohort. We applied logic regression (LR), a novel adaptive regression methodology, to search for high-order interactions. Exploratory genotype correlations with UC sub-phenotypes [extent of disease, need of surgery, age of onset, extra-intestinal manifestations and primary sclerosing cholangitis (PSC)] were conducted. The combination of 133 UC loci yielded good UC risk predictability [area under the curve (AUC) of 0.86]. A higher cumulative allele score predicted higher UC risk. Through LR, several lines of evidence for genetic interactions were identified and successfully replicated in the WTCCC cohort. The genetic interactions combined with the gene-smoking interaction significantly improved predictability in the model (AUC, from 0.86 to 0.89, P = 3.26E-05). Explained UC variance increased from 37 to 42 % after adding the interaction terms. A within case analysis found suggested genetic association with PSC. Our study demonstrates that the LR methodology allows the identification and replication of high-order genetic interactions in UC GWAS datasets. UC risk can be predicted by a 133 loci and improved by adding gene-gene and gene-environment interactions. PMID:24241240

Wang, Ming-Hsi; Fiocchi, Claudio; Zhu, Xiaofeng; Ripke, Stephan; Kamboh, M Ilyas; Rebert, Nancy; Duerr, Richard H; Achkar, Jean-Paul

2014-05-01

51

Estimation of Gene-Environment Interaction by Pooling Biospecimens  

PubMed Central

Summary Case-control studies are prone to low power for testing gene-environment interactions (GXE) given the need for a sufficient number of individuals on each strata of disease, gene, and environment. We propose a new study design to increase power by strategically pooling biospecimens. Pooling biospecimens allows us to increase the number of subjects significantly, thereby providing substantial increase in power. We focus on a special, though realistic case, where disease and environmental statuses are binary, and gene status is ordinal with each individual having 0, 1 or 2 minor alleles. Through pooling, we obtain an allele frequency for each level of disease and environmental status. Using the allele frequencies, we develop new methodology for estimating and testing GXE that is comparable to the situation when we have complete data on gene status for each individual. We also explore the measurement process and its effect on the GXE estimator. Using an illustration, we show the effectiveness of pooling with an epidemiologic study which tests an interaction for fiber and PON1 on anovulation. Through simulation, we show that taking 12 pooled measurements from 1000 individuals achieves more power than individually genotyping 500 individuals. Our findings suggest that strategic pooling should be considered when an investigator designs a pilot study to test for a GXE.

Danaher, M.R.; Schisterman, E.F.; Roy, A.; Albert, P.S.

2014-01-01

52

CD14 tobacco gene-environment interaction in atopic children.  

PubMed

Studying gene-environment interactions may elucidate the complex origins of atopic diseases. The aim of this study was to evaluate the association of CD14 polymorphisms and atopy in Egyptian children and to study whether atopy is influenced by CD14 interaction with tobacco smoke exposure. CD14 -159 C/T and CD14 -550 C/T were genotyped in 500 asthmaic children, 150 allergic rhinitis children and 150 controls. We found that CD14 -159T allele, CD14 -550T allele and CD14 -159T/-550T haplotype were significantly associated with atopic asthma and allergic rhinitis groups. CD14 -159 TT and CD14 -550 TT genotypes associated with elevated IgE levels in children exposed to tobacco smoke. The TT genotype of CD14 -159 C/T and CD14 -550 C/T was associated with higher serum levels of sCD14. The present study indicated that CD14 gene polymorphisms may contribute to susceptibility to atopy in Egyptian children and influenced with tobacco smoke exposure. PMID:24044964

Hussein, Yousri M; Shalaby, Sally M; Zidan, Haidy E; Sabbah, Norhan A; Karam, Nehad A; Alzahrani, Saad S

2013-01-01

53

BPD'S INTERPERSONAL HYPERSENSITIVITY PHENOTYPE: A GENE-ENVIRONMENT-DEVELOPMENTAL MODEL  

PubMed Central

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

Gunderson, John G.; Lyons-Ruth, Karlen

2008-01-01

54

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

55

Efficient Designs of Gene-Environment Interaction Studies: Implications of Hardy-Weinberg Equilibrium and Gene-Environment Independence  

PubMed Central

SUMMARY It is important to investigate whether genetic susceptible variants exercise the same effects in populations that are differentially exposed to environmental risk factors. Here, we assess the power of four two-phase case-control design strategies for assessing multiplicative gene-environment (G-E) interactions or for assessing genetic or environmental effects in the presence of G-E interactions. With a di-allelic SNP and a binary E, we obtained closed-form maximum likelihood estimates of both main effect and interaction odds ratio parameters under the constraints of G-E independence and Hardy-Weinberg Equilibrium, and used the Wald statistic for all tests. We concluded that i) for testing G-E interactions or genetic effects in the presence of G-E interactions when data for E is fully available, it is preferable to ascertain data for G in a subsample of cases with similar numbers of exposed and unexposed and a random subsample of controls; and ii) for testing G-E interactions or environmental effects in the presence of G-E interactions when data for G is fully available, it is preferable to ascertain data for E in a subsample of cases that has similar numbers for each genotype and a random subsample of controls. In addition, supplementing external control data to an existing casecontrol sample leads to improved power for assessing effects of G or E in the presence of G-E interactions.

Chen, Jinbo; Kang, Guolian; VanderWeele, Tyler; Zhang, Cuilin; Mukherjee, Bhramar

2012-01-01

56

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.

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

2014-01-01

57

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

PubMed Central

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

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

2011-01-01

58

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

59

Harold get. Elam K. Lewis G. Rice F. Thapar A. (2013). Integrating family socialisation intergenerational transmission hypotheses underlying childhood antisocial Behavior: role winter-parental conflict passive-genotype environment correlation. Development Psychopathology 25(1) 37-50.  

EPA Pesticide Factsheets

Did you mean: Harold get. Elam K. Lewis G. Rice F. Thapar A. (2013). Integrating family socialisation intergenerational transmission hypotheses underlying childhood antisocial Behavior: role winter-parental conflict passive-genotype environment correlation. Development Psychopathology 25(1) 37-50. ?

60

Genes, environments, and developmental GEWIS: Methods for a multi-site study of early substance abuse  

PubMed Central

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

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

2013-01-01

61

Passive exoskeleton  

US Patent & Trademark Office Database

The present invention relates to a load bearing apparatus, and more particularly, to a passive exoskeleton whereby a load may be placed on the passive exoskeleton and thereby transfer weight of the load from the passive exoskeleton to a ground surface. The passive exoskeleton comprises a rigid body member for attaching proximate a portion of a user's body, a sliding rod attached with the body member, and a ground surface engage-able foot analog attached with the sliding rod. When a user places a load on the body member, weight of the load from is transferred from the body member, through the sliding rod, and into the foot analog, causing the passive exoskeleton to support at least a portion of the load.

2009-08-11

62

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

Christmann, Edwin P.; Badgett, John L.

2008-11-01

63

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

PubMed Central

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

Idaghdour, Youssef; Awadalla, Philip

2013-01-01

64

Passive euthanasia  

PubMed Central

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

Garrard, E; Wilkinson, S

2005-01-01

65

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

66

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

67

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

68

BOGENVI: A Biomedical Ontology for Modelling Gene*Environment Interactions on Intermediate Phenotypes in Nutrigenomics Research  

Microsoft Academic Search

Nutritional Genomics is demanding computing models and technological platforms in order to support acquisition, storage, management and presentation of all the information generated coming from heterogeneous sources: genotypes, environmental factors (diet and other life-style factors) and phenotypes (intermediate and final phenotypes). Our aim is to build a biomedical ontology in order to modelling gene*environment interactions on intermediate phenotypes by means

Antonio Fabregat; Elisabet Barrera; María Arregui; Olga Portolés; Dolores Corella; Óscar Coltell

2008-01-01

69

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

70

Case-Control Studies of Gene-Environment Interaction: Bayesian Design and Analysis  

PubMed Central

Summary With increasing frequency, epidemiologic studies are addressing hypotheses regarding gene-environment interaction. In many well studied candidate genes and for standard dietary and behavioral epidemiologic exposures, there is often substantial prior information available which may be used to analyze current data as well as for designing a new study. In this paper, first, we propose a proper full Bayesian approach for analyzing studies of gene-environment interaction. The Bayesian approach provides a natural way to incorporate uncertainties around the assumption of gene-environment independence, often used in such analysis. We then consider Bayesian sample size determination criteria for both estimation and hypothesis testing regarding the multiplicative gene-environment interaction parameter. We illustrate our proposed methods using data from a large ongoing case-control study of colorectal cancer investigating the interaction of N-acetyl transferase type 2 (NAT2) with smoking and red meat consumption. We use the existing data to elicit a design prior and show how to use this information in allocating cases and controls in planning a future study which investigates the same interaction parameters. The Bayesian design and analysis strategies are compared with their corresponding frequentist counterparts.

Mukherjee, Bhramar; Ahn, Jaeil; Gruber, Stephen B.; Ghosh, Malay; Chatterjee, Nilanjan

2011-01-01

71

Multifactor dimensionality reduction software for detecting gene-gene and gene-environment interactions  

Microsoft Academic Search

Motivation: Polymorphisms in human genes are being described in remarkable numbers. Determining which polymorphisms and which environmental factors are associated with common, complex diseases has become a daunting task. This is partly because the effect of any single genetic variation will likely be dependent on other genetic variations (gene-gene interaction or epistasis) and environmental factors (gene-environment interac- tion). Detecting and

Lance W. Hahn; Marylyn D. Ritchie; Jason H. Moore

2003-01-01

72

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

PubMed Central

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

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

2013-01-01

73

Passive Maser.  

National Technical Information Service (NTIS)

A passive maser wherein control of the cavity and control of the oscillator on the line of stimulated emission operate in a shared-time mode. A control circuit acts on the injected signal by way of a programmable synthesizer, the injected signal then assu...

A. H. Frank J. D. White

1981-01-01

74

Passive Accelerometer  

NASA Technical Reports Server (NTRS)

Motion of ball in liquid indicates acceleration. Passive accelerometer measures small accelerations along cylindrical axis. Principle of operation based on Stokes' law. Provides accurate measurements of small quasi-steady accelerations. Additional advantage, automatically integrates out unwanted higher-frequency components of acceleration.

Naumann, Robert J.; Baugher, Charles; Alexander, Iwan

1992-01-01

75

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.

76

Genome-Wide Meta-Analysis of Joint Tests for Genetic and Gene-Environment Interaction Effects  

Microsoft Academic Search

Background: There is growing interest in the study of gene-environment interactions in the context of genome-wide association studies (GWASs). These studies will likely require meta-analytic approaches to have sufficient power. Methods: We describe an approach for meta-analysis of a joint test for genetic main effects and gene-environment interaction effects. Using simulation studies based on a meta-analysis of five studies (total

Hugues Aschard; Dana B. Hancock; Stephanie J. London; Peter Kraft

2010-01-01

77

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

78

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

PubMed

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

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

2013-09-01

79

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

PubMed Central

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

2013-01-01

80

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

PubMed Central

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

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

2010-01-01

81

Environmental and gene-environment interactions and risk of rheumatoid arthritis  

PubMed Central

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

Karlson, Elizabeth W.; Deane, Kevin

2012-01-01

82

Behavior of QQ-plots and genomic control in studies of gene-environment interaction.  

PubMed

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 G x E 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 theory, we show how and why spurious QQ-plot inflation occurs in G x E GWAS, and how this differs from main-effects analyses. We also explain how simple adjustments to standard regression-based methods used in G x E GWAS can alleviate this problem. PMID:21589913

Voorman, Arend; Lumley, Thomas; McKnight, Barbara; Rice, Kenneth

2011-01-01

83

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.

Daw, Jonathan; Freese, Jeremy

2013-01-01

84

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.

Horowitz, MP; Greenamyre, JT

2011-01-01

85

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

PubMed Central

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 that common variants at candidate genes for lipid metabolism, inflammation, and obesity are associated with altered plasma levels of classic and new biomarkers of metabolic syndrome and CVD risk. Major contributors to this knowledge have been a series of large population studies containing phenotype-rich databases and dietary information to which genetic data have been added. Although this approach has provided strong evidence supporting the concept of gene–diet interactions modulating CVD risk factors, the strength of the individual effect is very small, and the replication among studies is rather disappointing. Current population studies are starting to incorporate experimental and analytical approaches that could provide more solid and comprehensive results. However, other limitations, such as the size of the populations required to examine higher-level interactions, are still major obstacles to translating this knowledge into practical public health applications. Nevertheless, data from numerous molecular and genetic epidemiological studies provide tantalizing evidence suggesting that gene–environment interactions, i.e., the modulation by a genetic polymorphism of a dietary component effect on a specific phenotype (e.g., cholesterol levels and obesity), can interact in ways that increase the risk for developing chronic disease, including susceptibility to developing the metabolic syndrome. Once further experience is gained from patients and/or individuals at high risk, more personalized genetic-based approaches may be applied toward the primary prevention and treatment of CVDs and other complex inflammatory diseases.

Ordovas, Jose M.; Shen, Jian

2009-01-01

86

Role of African Ancestry and Gene-Environment Interactions in Predicting Preterm Birth  

PubMed Central

Objective To estimate whether African ancestry, specific gene polymorphisms, and gene-environment interactions could account for some of the unexplained preterm birth variance within blacks. Methods We genotyped 1,509 African ancestry informative markers, cytochrome P-450 1A1 (CYP1A1) and glutathione S-transferases Theta 1 (GSTT1) variants in 1,030 self-reported black mothers. We estimated the African ancestral proportion using the ancestry informative markers for all 1,030 self-reported black mothers. We examined the effect of African ancestry and CYP1A1 and GSTT1 smoking interactions on preterm birth cases as a whole and within its subgroups: very preterm birth (gestational age less than 34 weeks); and late preterm birth (gestational age greater than 34 and less than 37 weeks). We applied logistic regression and receiver operating characteristic (ROC) curve analysis, separately, to evaluate if African ancestry and CYP1A1- and GSTT1-smoking interactions could make additional contributions to preterm birth beyond epidemiological factors. Results We found significant associations of African ancestry with preterm birth (22% vs. 31%, OR=1.11; 95%CI: 1.02–1.20) and very preterm birth (23% vs. 33%, OR=1.17; 95%CI: 1.03–1.33), but not with late preterm birth (22% vs. 29%, OR=1.06; 95%CI: 0.97–1.16). In addition, the ROC curve analysis suggested that African ancestry and CYP1A1- and GSTT1-smoking interactions made substantial contributions to very preterm birth beyond epidemiologic factors. Conclusion Our data underscore the importance of simultaneously considering epidemiological factors, African ancestry, specific gene polymorphisms and gene-environment interactions to better understand preterm birth racial disparity and to improve our ability to predict preterm birth, especially very preterm birth.

Tsai, Hui-Ju; Hong, Xiumei; Chen, Jinbo; Liu, Xin; Pearson, Colleen; Ortiz, Katherin; Hirsch, Emmet; Heffner, Linda; Weeks, Daniel E.; Zuckerman, Barry; Wang, Xiaobin

2011-01-01

87

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.

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

2011-01-01

88

Hood River Passive House.  

National Technical Information Service (NTIS)

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 a...

D. Hales

2013-01-01

89

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

90

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

91

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

92

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

93

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

PubMed Central

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.

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

2013-01-01

94

THE AUTISM BIRTH COHORT (ABC): A PARADIGM FOR GENE-ENVIRONMENT-TIMING RESEARCH  

PubMed Central

The reported prevalence of autism spectrum disorders (ASD) has increased 5–10× over the past 20 years. Whether ASD are truly more frequent is controversial; nonetheless, the burden is profound in human and economic terms. Although autism is among the most heritable of mental disorders, its pathogenesis remains obscure. Environmental factors are proposed; however, none is implicated. Furthermore, there are no biomarkers to screen for ASD or risk of ASD. The Autism Birth Cohort (ABC) was initiated to investigate gene × environment × timing interactions and enable early diagnosis. It employs a large, unselected birth cohort wherein cases are prospectively ascertained through population screening. Samples collected serially through pregnancy and childhood include parental blood, maternal urine, cord blood, milk teeth and rectal swabs. More than 107 000 children are continuously screened via questionnaires, referral and a national registry. Cases are compared with a control group from the same cohort in a “nested case-control” design. Early screening, diagnostic assessments and re-assessments are designed to provide a rich view of longitudinal trajectory. Genetic, proteomic, immunologic, metagenomic and microbiological tools will be used to exploit unique biological samples. The ABC is a paradigm for investigating the role of genetic and environmental factors in complex disorders.

Stoltenberg, Camilla; Schj?lberg, Synnve; Bresnahan, Michaeline; Hornig, Mady; Hirtz, Deborah; Dahl, Cathrine; Lie, Kari Kveim; Reichborn-Kjennerud, Ted; Schreuder, Patricia; Alsaker, Elin; ?yen, Anne-Siri; Magnus, Per; Suren, Pal; Susser, Ezra; Lipkin, W. Ian

2010-01-01

95

Identifying Gene-Environment Interactions in Schizophrenia: Contemporary Challenges for Integrated, Large-scale Investigations.  

PubMed

Recent years have seen considerable progress in epidemiological and molecular genetic research into environmental and genetic factors in schizophrenia, but methodological uncertainties remain with regard to validating environmental exposures, and the population risk conferred by individual molecular genetic variants is small. There are now also a limited number of studies that have investigated molecular genetic candidate gene-environment interactions (G × E), however, so far, thorough replication of findings is rare and G × E research still faces several conceptual and methodological challenges. In this article, we aim to review these recent developments and illustrate how integrated, large-scale investigations may overcome contemporary challenges in G × E research, drawing on the example of a large, international, multi-center study into the identification and translational application of G × E in schizophrenia. While such investigations are now well underway, new challenges emerge for G × E research from late-breaking evidence that genetic variation and environmental exposures are, to a significant degree, shared across a range of psychiatric disorders, with potential overlap in phenotype. PMID:24860087

2014-07-01

96

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

PubMed Central

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

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

2009-01-01

97

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

98

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

PubMed Central

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

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

2012-01-01

99

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.

Harden, K. Paige; Mendle, Jane

2014-01-01

100

A combinatorial approach to detecting gene-gene and gene-environment interactions in family studies.  

PubMed

Widespread multifactor interactions present a significant challenge in determining risk factors of complex diseases. Several combinatorial approaches, such as the multifactor dimensionality reduction (MDR) method, have emerged as a promising tool for better detecting gene-gene (G x G) and gene-environment (G x E) interactions. We recently developed a general combinatorial approach, namely the generalized multifactor dimensionality reduction (GMDR) method, which can entertain both qualitative and quantitative phenotypes and allows for both discrete and continuous covariates to detect G x G and G x E interactions in a sample of unrelated individuals. In this article, we report the development of an algorithm that can be used to study G x G and G x E interactions for family-based designs, called pedigree-based GMDR (PGMDR). Compared to the available method, our proposed method has several major improvements, including allowing for covariate adjustments and being applicable to arbitrary phenotypes, arbitrary pedigree structures, and arbitrary patterns of missing marker genotypes. Our Monte Carlo simulations provide evidence that the PGMDR method is superior in performance to identify epistatic loci compared to the MDR-pedigree disequilibrium test (PDT). Finally, we applied our proposed approach to a genetic data set on tobacco dependence and found a significant interaction between two taste receptor genes (i.e., TAS2R16 and TAS2R38) in affecting nicotine dependence. PMID:18834969

Lou, Xiang-Yang; Chen, Guo-Bo; Yan, Lei; Ma, Jennie Z; Mangold, Jamie E; Zhu, Jun; Elston, Robert C; Li, Ming D

2008-10-01

101

Gene-environment interactions in asthma and allergic diseases: challenges and perspectives.  

PubMed

The concept of gene-environment (GxE) interactions has dramatically evolved in the last century and has now become a central theme in studies that assess the causes of human disease. Despite the numerous efforts to discover genes associated in asthma and allergy through various approaches, including the recent genome-wide association studies, investigation of GxE interactions has been mainly limited to candidate genes, candidate environmental exposures, or both. This review discusses the various strategies from hypothesis-driven strategies to the full agnostic search of GxE interactions with an illustration from recently published articles. Challenges raised by each piece of the puzzle (ie, phenotype, environment, gene, and analysis of GxE interaction) are put forward, and tentative solutions are proposed. New perspectives to integrate various types of data generated by new sequencing technologies and to progress toward a systems biology approach of disease are outlined. The future of a molecular network-based approach of disease to which GxE interactions are related requires space for innovative and multidisciplinary research. Assembling the various parts of a puzzle in a complex system could well occur in a way that might not necessarily follow the rules of logic. PMID:23195523

Kauffmann, Francine; Demenais, Florence

2012-12-01

102

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

PubMed

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

Mandelli, Laura; Serretti, Alessandro

2013-12-01

103

Effects of gene-environment interactions on cardiovascular risk factors in Chinese adolescent twins.  

PubMed

A population-based sample of 73 male and 77 female monozygotic (MZ), and 41 male and 33 female dizygotic (DZ) Chinese adolescent twin pairs were studied to assess effects of gene-environment interactions of systolic blood pressure (SBP), diastolic blood pressure (DBP), serum cholesterol and triglyceride levels. Intrapair concordance in BP levels was found to be significantly associated with the interaction of zygosity and salty foods preference and also with that of zygosity and vegetable preference. A consistently positive and statistically significant association was observed between the intrapair difference in serum cholesterol and the interaction of zygosity and animal organ preference; while intrapair concordance in serum cholesterol was associated with the interaction of zygosity and milk consumption. Intrapair difference in serum triglycerides was associated with the interaction of zygosity and fish preference, and a significant association was also found between the intrapair concordance in serum triglycerides and the interaction of zygosity and sweets preference. These observations suggest that the impact of these environmental agents may be influenced by the genotype. PMID:6543273

Chen, C J; Cohen, B H; Diamond, E L; Lin, T M; Chen, J S

1984-01-01

104

Gene-Environment Interaction of Body Mass Index and Apolipoprotein E ?4 Allele on Cognitive Decline.  

PubMed

Genetic variation alone may not account for common chronic disease susceptibility. Rather, an interaction between genetic and environmental factors may clarify the underlying disease mechanism. Hence, we tested whether body mass index (BMI) modified the genetic association of the apolipoprotein E ?4 allele with cognitive decline. The data came from a longitudinal population-based sample of 4055 participants interviewed at 3-year intervals from 1993 to 2012. Cognitive function was assessed using a standardized global cognitive score and BMI was assessed at baseline and classified as normal, overweight, and obese. There were 1374 (34%) participants with the ?4 allele. In normal BMI participants, cognitive decline was 0.048 units/y without the ?4 allele, and increased by an additional 0.031 units/y with the ?4 allele. In overweight participants, cognitive decline was 0.038 units/y without the ?4 allele, and increased by an additional 0.026 units/y with the ?4 allele. Finally, in obese participants, cognitive decline was 0.038 units/y without the ?4 allele, and increased by an additional 0.014 units/y with the ?4 allele. The association of ?4 allele with cognitive decline was significantly lower in obese participants compared with normal BMI participants (P=0.003), thereby suggesting significant gene-environment interaction on cognitive decline. PMID:24145695

Rajan, Kumar B; Skarupski, Kimberly A; Rasmussen, Heather E; Evans, Denis A

2014-01-01

105

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

PubMed

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

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

2011-04-01

106

Gene-environment interplay in the association between pubertal timing and delinquency in adolescent girls.  

PubMed

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 nonviolent and violent delinquency. Moreover, after accounting for this genetic association between pubertal timing and delinquency, the impact of nonshared environmental influences on delinquency are significantly moderated by pubertal timing, such that the nonshared environment is most important among early maturing girls. This interaction effect is particularly evident for nonviolent 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

2012-02-01

107

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.

Gao, Hui-Ming; Hong, Jau-shyong

2011-01-01

108

Gene-Environment Interactions of Novel Variants Associated with Head and Neck Cancer  

PubMed Central

Background A genome-wide association study for upper aerodigestive tract cancers identified 19 candidate single-nucleotide polymorphisms (SNPs). We used these SNPs to investigate the potential gene-gene and gene-environment interactions in head and neck squamous cell carcinoma (HNSCC) risk. Methods The 19 variants were genotyped using Taqman (Applied Biosystems) assays among 575 cases and 676 controls in our population-based case-control study. Results A restricted cubic spline model suggested both ADH1B and HEL308 modified the association between smoking pack-years and HNSCC. Classification and regression tree analysis demonstrated a higher order interaction between smoking status, ADH1B, FLJ13089 and FLJ35784 in HNSCC risk. Compared with ever smokers carrying ADH1B T/C+T/T genotypes, smokers carrying ADH1B C/C genotype and FLJ13089 A/G+A/A genotypes had a highest risk of HNSCC (OR=1.84). Conclusions Our results suggest that the risk associated with these variants may be specifically important amongst specific exposure groups.

Liang, Caihua; Marsit, Carmen J.; Houseman, E. Andres; Butler, Rondi; Nelson, Heather H.; McClean, Michael D.; Kelsey, Karl T.

2013-01-01

109

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

PubMed Central

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

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

2013-01-01

110

A genome-wide gene-environment interaction analysis for tobacco smoke and lung cancer susceptibility.  

PubMed

Tobacco smoke is the major environmental risk factor underlying lung carcinogenesis. However, approximately one-tenth smokers develop lung cancer in their lifetime indicating there is significant individual variation in susceptibility to lung cancer. And, the reasons for this are largely unknown. In particular, the genetic variants discovered in genome-wide association studies (GWAS) account for only a small fraction of the phenotypic variations for lung cancer, and gene-environment interactions are thought to explain the missing fraction of disease heritability. The ability to identify smokers at high risk of developing cancer has substantial preventive implications. Thus, we undertook a gene-smoking interaction analysis in a GWAS of lung cancer in Han Chinese population using a two-phase designed case-control study. In the discovery phase, we evaluated all pair-wise (591 370) gene-smoking interactions in 5408 subjects (2331 cases and 3077 controls) using a logistic regression model with covariate adjustment. In the replication phase, promising interactions were validated in an independent population of 3023 subjects (1534 cases and 1489 controls). We identified interactions between two single nucleotide polymorphisms and smoking. The interaction P values are 6.73 × 10(-) (6) and 3.84 × 10(-) (6) for rs1316298 and rs4589502, respectively, in the combined dataset from the two phases. An antagonistic interaction (rs1316298-smoking) and a synergetic interaction (rs4589502-smoking) were observed. The two interactions identified in our study may help explain some of the missing heritability in lung cancer susceptibility and present strong evidence for further study of these gene-smoking interactions, which are benefit to intensive screening and smoking cessation interventions. PMID:24658283

Zhang, Ruyang; Chu, Minjie; Zhao, Yang; Wu, Chen; Guo, Huan; Shi, Yongyong; Dai, Juncheng; Wei, Yongyue; Jin, Guangfu; Ma, Hongxia; Dong, Jing; Yi, Honggang; Bai, Jianling; Gong, Jianhang; Sun, Chongqi; Zhu, Meng; Wu, Tangchun; Hu, Zhibin; Lin, Dongxin; Shen, Hongbing; Chen, Feng

2014-07-01

111

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.

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

2012-01-01

112

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

PubMed Central

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

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

2013-01-01

113

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.

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

2014-01-01

114

Preliminary Evidence for a Gene-Environment Interaction in Predicting Alcohol Use Disorders in Adolescents  

PubMed Central

Background Emerging research suggests that genetic influences on adolescent drinking are moderated by environmental factors. The present study builds on molecular-genetic findings by conducting the first analysis of gene-environment interactions in the association between a functional single nucleotide polymorphism (SNP) of the µ-opioid receptor (OPRM1) gene (A118G) and risk for developing an alcohol use disorder (AUD) during adolescence. Specifically, we tested whether variation in parenting practices or affiliation with deviant peers moderated the link between the OPRM1 gene and risk for an AUD. Methods Adolescents reporting European ancestry (N = 104), ages 12–19 years (M = 15.60, SD = 1.77), were interviewed to ascertain AUD diagnoses, provided a DNA sample for genetic analyses, and completed measures of parental monitoring and deviant peer affiliation. Logistic regression was used to test the effects of environmental variable sand their interactions with OPRM1genotype as predictors of AUD diagnosis while controlling for age and sex. Results Case-control comparisons showed that the proportion of youth with an AUD (n = 18) significantly differed by genotype such that 33.3% of G allele carriers met criteria for an AUD compared to 10.8% of youth who were homozygous for the A allele (p = .006). The OPRM1 × parental monitoring (odds ratio = 0.16) and OPRM1 × deviant peer affiliation (odds ratio = 7.64) interactions were significant predictors of AUD risk, such that G allele carriers with high levels of deviant peer affiliation or lower levels of parental monitoring had the greatest likelihood of developing an AUD (p values < .01). Conclusions This study provides initial evidence that the association between the A118G SNP of the OPRM1 gene and risk for AUDs is moderated by modifiable factors. These results are limited, however, by the small sample size and require replication.

Miranda, Robert; Reynolds, Elizabeth; Ray, Lara; Justus, Alicia; Knopik, Valerie S.; McGeary, John; Meyerson, Lori A.

2013-01-01

115

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

116

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.

Conley, Dalton

2013-01-01

117

Some Key Issues in the Study of Gene–Environment Interplay: Activation, Deactivation, and the Role of Development  

Microsoft Academic Search

Gene–environment interaction (GxE) is thought to constitute a fundamental mechanism though which genes influence human behavior. In the excitement about GxE, however, the deliberative approach that typically characterizes empirical social science research has been inconsistently applied. The current review highlights areas where more work is needed. First, although most GxE research to date has focused on the augmentation of genetic

Alex Burt

2011-01-01

118

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.

Wallace, Helen M

2006-01-01

119

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

PubMed

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

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

2012-11-01

120

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

121

International passive architectural survey  

SciTech Connect

An international survey of research, development, and demonstration in the passive solar design field was begun in October 1979 by the Solar Energy Reseach Institute's Passive Technology Program, and was completed in September 1980. Results will be available in late fall 1980.

Holtz, M. (Solar Energy Reseach Inst., Golden, CO); Diachok, D.; Shanks, D.

1980-01-01

122

Passive magnetic bearing configurations  

DOEpatents

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

Post, Richard F. (Walnut Creek, CA) [Walnut Creek, CA

2011-01-25

123

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

124

Passive Solar Design  

NSDL National Science Digital Library

Students are introduced to passive solar design for buildings â 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.

Integrated Teaching And Learning Program

125

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

126

Passive Seismic Reflectivity Imaging with Ocean-Bottom Cable Data  

Microsoft Academic Search

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

D. Hohl; A. Mateeva

2005-01-01

127

Coherent optical processing of passive signals  

Microsoft Academic Search

The dynamic range, resolution and nonlinear response of the data planes in an optical processor affect the performance of an optical correlator. These system issues are addressed for the passive signal processing problem assuming random variable signals. It is shown that quantization is of no concern for random signal and a new parameter, space blur bandwidth product is introduced to

B. V. K. Vijayakumar

1980-01-01

128

High-throughput phenotypic profiling of gene-environment interactions by quantitative growth curve analysis in Saccharomyces cerevisiae.  

PubMed

Cell-based assays are widely used in high-throughput screening to determine the effects of toxicants and drugs on their biological targets. To enable a functional genomics modeling of gene-environment interactions, quantitative assays are required both for gene expression and for the phenotypic responses to environmental challenge. To address this need, we describe an automated high-throughput methodology that provides phenotypic profiling of the cellular responses to environmental stress in Saccharomyces cerevisiae. Standardized assay conditions enable the use of a single metric value to quantify yeast microculture growth curves. This assay format allows precise control of both genetic and environmental determinants of the cellular responses to oxidative stress, a common mechanism of environmental insult. These yeast-cell-based assays are validated with hydrogen peroxide, a simple direct-acting oxidant. Phenotypic profiling of the oxidative stress response of a yap1 mutant strain demonstrates the mechanistic analysis of genetic susceptibility to oxidative stress. As a proof of concept for analysis of more complex gene-environment interactions, we describe a combinatorial assay design for phenotypic profiling of the cellular responses to tert-butyl hydroperoxide, a complex oxidant that is actively metabolized by its target cells. Thus, the yeast microculture assay format supports comprehensive applications in toxicogenomics. PMID:15033507

Weiss, Andrew; Delproposto, James; Giroux, Craig N

2004-04-01

129

Nonparametric Bayesian variable selection with applications to multiple quantitative trait loci mapping with epistasis and gene-environment interaction.  

PubMed

The joint action of multiple genes is an important source of variation for complex traits and human diseases. However, mapping genes with epistatic effects and gene-environment interactions is a difficult problem because of relatively small sample sizes and very large parameter spaces for quantitative trait locus models that include such interactions. Here we present a nonparametric Bayesian method to map multiple quantitative trait loci (QTL) by considering epistatic and gene-environment interactions. The proposed method is not restricted to pairwise interactions among genes, as is typically done in parametric QTL analysis. Rather than modeling each main and interaction term explicitly, our nonparametric Bayesian method measures the importance of each QTL, irrespective of whether it is mostly due to a main effect or due to some interaction effect(s), via an unspecified function of the genotypes at all candidate QTL. A Gaussian process prior is assigned to this unknown function. In addition to the candidate QTL, nongenetic factors and covariates, such as age, gender, and environmental conditions, can also be included in the unspecified function. The importance of each genetic factor (QTL) and each nongenetic factor/covariate included in the function is estimated by a single hyperparameter, which enters the covariance function and captures any main or interaction effect associated with a given factor/covariate. An initial evaluation of the performance of the proposed method is obtained via analysis of simulated and real data. PMID:20551445

Zou, Fei; Huang, Hanwen; Lee, Seunggeun; Hoeschele, Ina

2010-09-01

130

The logistic regression model for gene-environment interactions using both case-parent trios and unrelated case-controls.  

PubMed

One of the greatest challenges in genetic studies is the determination of gene-environment interactions due to underlying complications and inadequate statistical power. With the increased sample size gained by using case-parent trios and unrelated cases and controls, the performance may be much improved. Focusing on a dichotomous trait, a two-stage approach was previously proposed to deal with gene-environment interaction when utilizing mixed study samples. Theoretically, the two-stage association analysis uses likelihood functions such that the computational algorithms may not converge in the maximum likelihood estimation with small study samples. In an effort to avoid such convergence issues, we propose a logistic regression framework model, based on the combined haplotype relative risk (CHRR) method, which intuitively pools the case-parent trios and unrelated subjects in a two by two table. A positive feature of the logistic regression model is the effortless adjustment for either discrete or continuous covariates. According to computer simulations, under the circumstances in which the two-stage test converges in larger sample sizes, we discovered that the performances of the two tests were quite similar; the two-stage test is more powerful under the dominant and additive disease models, but the extended CHRR is more powerful under the recessive disease model. PMID:24766627

Guo, Chao-Yu; Chen, Yu-Jing; Chen, Yi-Hau

2014-07-01

131

ACR-1000 Passive Features  

SciTech Connect

The Advanced CANDU Reactor{sup TM} (ACR{sup TM}) is a Generation III+ pressure tube type reactor using light water coolant and heavy water moderator. The ACR-1000 reactor design is an evolutionary extension of the proven CANDU reactor design. The ACR-1000 incorporates multiple and diverse passive systems for accident mitigation. Where necessary, one or more features that are passive in nature have been included for mitigation of any postulated accident event. This paper describes how the use of passive design elements complements active features enhances reliability and improves safety margins. (authors)

Lekakh, Boris; Hau, Ken; Ford, Steven [Atomic Energy of Canada Ltd. (Canada)

2006-07-01

132

Passive Explosion Barrier.  

National Technical Information Service (NTIS)

The patent application relates generally to explosion barriers for mines, or the like, and more particularly to a passive explosion barrier that is responsive to relatively low velocity, as well as intermediate and high velocity explosion generated wind, ...

Liebman Corry

1975-01-01

133

Passive MIMO Radar Detection.  

National Technical Information Service (NTIS)

Passive multiple-input multiple-output (MIMO) radar is a sensor network comprised of multiple distributed receivers that detects and localizes targets using the emissions from multiple non-cooperative radio frequency transmitters. This dissertation advanc...

D. E. Hack

2013-01-01

134

Passive-Solar Greenhouse.  

National Technical Information Service (NTIS)

Our project objective was to design, construct, and operate a commercialized (16' x 50') passive, solar greenhouse. The structure was originally intended as a vegetable forcing facility to produce vegetable crops in the off-season. Building and size const...

1982-01-01

135

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.

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

2012-01-01

136

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

PubMed Central

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

Niculescu, Mihai D.; Jackson, Robert T.

2013-01-01

137

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.

2013-01-01

138

Wireless passive radiation sensor  

DOEpatents

A novel measurement technique is employed using surface acoustic wave (SAW) devices, passive RF, and radiation-sensitive films to provide a wireless passive radiation sensor that requires no batteries, outside wiring, or regular maintenance. The sensor is small (<1 cm.sup.2), physically robust, and will operate unattended for decades. In addition, the sensor can be insensitive to measurement position and read distance due to a novel self-referencing technique eliminating the need to measure absolute responses that are dependent on RF transmitter location and power.

Pfeifer, Kent B; Rumpf, Arthur N; Yelton, William G; Limmer, Steven J

2013-12-03

139

Method of passivating semiconductor surfaces  

DOEpatents

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

Wanlass, M.W.

1990-06-19

140

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

141

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

142

Passives and Their Meaning  

ERIC Educational Resources Information Center

An underlying representation for passive sentences in Mojave and Uto-Aztecan is proposed, and the broader issues that arise in extending the analysis to other languages and incorporating it in linguistic theory as a substantive language universal are explored. (Author/RM)

Langacker, Ronald W.; Munro, Pamela

1975-01-01

143

Passive Ranging with Incoherent Systems.  

National Technical Information Service (NTIS)

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

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

1995-01-01

144

Electret-based passive dust sampler: sampling of organic dusts.  

PubMed

Passive samplers are light, convenient and cheap. However, the sample size tends to be small and a correlation exercise between the results of a passive sampler and a conventional sampler must be carried out. The design principles and mode of action of an electret-based passive dust sampler are described. The device captures dust particles at a rate independent of the velocity of air except when this is very low but dependent on the electrical properties of the dust being sampled. Experimental results are presented of measurements made in bakeries, pig farms, a dairy farm, an arable farm and a rubber-manufacturing plant. Correlation between measurements made with the passive sampler and measurements of inhalable dust performed by other means are reasonable. The results are interpreted in terms of the physical properties of the dust being sampled. PMID:8831282

Brown, R C; Hemingway, M A; Wake, D; Thorpe, A

1996-09-01

145

Gender-specific gene-environment interaction in alcohol dependence: the impact of daily life events and GABRA2.  

PubMed

Gender-moderated gene-environment interactions are rarely explored, raising concerns about inaccurate specification of etiological models and inferential errors. The current study examined the influence of gender, negative and positive daily life events, and GABRA2 genotype (SNP rs279871) on alcohol dependence, testing two- and three-way interactions between these variables using multi-level regression models fit to data from 2,281 White participants in the Collaborative Study on the Genetics of Alcoholism. Significant direct effects of variables of interest were identified, as well as gender-specific moderation of genetic risk on this SNP by social experiences. Higher levels of positive life events were protective for men with the high-risk genotype, but not among men with the low-risk genotype or women, regardless of genotype. Our findings support the disinhibition theory of alcohol dependence, suggesting that gender differences in social norms, constraints and opportunities, and behavioral undercontrol may explain men and women's distinct patterns of association. PMID:23974430

Perry, Brea L; Pescosolido, Bernice A; Bucholz, Kathleen; Edenberg, Howard; Kramer, John; Kuperman, Samuel; Schuckit, Marc Alan; Nurnberger, John I

2013-09-01

146

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.

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

147

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

PubMed Central

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

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

2012-01-01

148

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

PubMed

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

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

2012-10-16

149

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

150

Passive chevron replicator  

NASA Technical Reports Server (NTRS)

There is described a passive replicator device to be used in magnetic bubble domain systems. The replicator is passive, i.e., does not require an active element such as a current source or the like, and both propagates and replicates bubble domains. In a preferred embodiment, the replicator uses chevron type elements arranged in an appropriate pattern so as to interact with a pair of propagation paths wherein bubble domains are propagated. A bubble in one propagation path is routinely transferred therealong and, concurrently, replicated by the instant device into another propagation path. A plurality of elements arranged in juxtaposition to the chevrons assists in controlling the propagation of the bubbles through the respective propagation paths and, at the appropriate time, provides a cutting action wherein a bubble which is elongated between the chevrons of the two propagation paths is split into two separate bubbles.

Oeffinger, Thomas R. (Inventor); Tocci, Leonard R. (Inventor)

1977-01-01

151

Passivation of stainless steel  

Microsoft Academic Search

This paper, the 19th in a series of articles on the hygienic design of food processing equipment published in TIFS, introduces the first joint EHEDG\\/3-A Update article in the series, a set of guidelines for the hygienic passivation of stainless steel surfaces intended for food-contact use. These guidelines have been prepared on behalf of the US-based 3-A Steering Committee and

R. R Maller

1998-01-01

152

Passive solar heating analysis  

SciTech Connect

A presentation of solar heating analysis methods developed at the Los Alamos National Laboratory, focusing on small residential and commercial buildings. This book gives building designers a solar sizing and evaluation guide. Tabulated values for 223 North American locations make the methods potentially useful anywhere in the United States and Canada. It establishes 30 guidelines that range from general rules relating to conservation, solar area and orientation, to passive solar system types.

Not Available

1984-01-01

153

Passive fetal monitoring sensor  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

154

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

PubMed Central

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

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

2011-01-01

155

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

PubMed

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

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

2014-07-01

156

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.

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

157

Evidence for gene-environment interaction in a genome wide study of isolated, non-syndromic cleft palate  

PubMed Central

Non-syndromic 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 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 non-syndromic CP.

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 C.; 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.

2011-01-01

158

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.

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

2013-01-01

159

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

160

Passive Immunization Against Poliomyelitis  

PubMed Central

Poliomyelitis has gone from being one of the worst scourges of the 20th century to nearing eradication in the 21st. This success is well known to be attributable to the Salk inactivated and Sabin attenuated poliovirus vaccines. However, before introduction of these vaccines, William McDowall Hammon of the University of Pittsburgh Graduate School of Public Health led the first major breakthrough in prevention of the disease by using passive immunization in one of the earliest double-blind, placebo-controlled clinical trials. This study provided the first evidence that antibodies to poliovirus could prevent the disease in humans.

Rinaldo, Charles R.

2005-01-01

161

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

162

Effects of initial conditions on the passive and active scalar fluxes in unsteady stably stratified turbulence  

NASA Astrophysics Data System (ADS)

Passive and active scalar fluxes in unsteady strongly stratified turbulence are analyzed using the rapid distortion theory (RDT). Analytical solutions of the RDT equations show that the initial conditions, i.e., the initial cross correlation between passive scalar and active scalar (density) and the initial potential energy, make a difference between the passive and active scalar flux, giving the difference between the turbulent diffusion coefficients for passive and active scalars. In other words even the initial zero correlation gives the complete correlation in the long time development, in contrast to the previous discussions in the literature based on the equations for stationary turbulence. The difference appears in the components slowly oscillating at half frequency N (N: Brunt-Väisälä frequency) in the passive scalar flux, while the active scalar flux has only the rapidly oscillating components which oscillate at frequency 2N. It is also found that the correlation coefficient between passive and active scalars is not a good measure of identifying the agreement or disagreement of the turbulent diffusion coefficients for these scalars, since the initially large passive scalar variance can lead to a final small correlation coefficient even when the turbulent diffusion coefficients are equal for the active and passive scalars. The results show the importance of unsteady analysis of the initial value problem in the diffusion problem in stratified turbulence.

Hanazaki, H.

2003-04-01

163

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

164

Matrix metalloproteinases and educational attainment in refractive error: evidence of gene-environment interactions in the AREDS study  

PubMed Central

Purpose A previous study of Old Order Amish families has shown association of ocular refraction with markers proximal to matrix metalloproteinase (MMP) genes MMP1 and MMP10 and intragenic to MMP2. We conducted a candidate gene replication study of association between refraction and single nucleotide polymorphisms (SNPs) within these genomic regions. Design Candidate gene genetic association study. Participants 2,000 participants drawn from the Age Related Eye Disease Study (AREDS) were chosen for genotyping. After quality control filtering, 1912 individuals were available for analysis. Methods Microarray genotyping was performed using the HumanOmni 2.5 bead array. SNPs originally typed in the previous Amish association study were extracted for analysis. In addition, haplotype tagging SNPs were genotyped using TaqMan assays. Quantitative trait association analyses of mean spherical equivalent refraction (MSE) were performed on 30 markers using linear regression models and an additive genetic risk model, while adjusting for age, sex, education, and population substructure. Post-hoc analyses were performed after stratifying on a dichotomous education variable. Pointwise (P-emp) and multiple-test study-wise (P-multi) significance levels were calculated empirically through permutation. Main outcome measures MSE was used as a quantitative measure of ocular refraction. Results The mean age and ocular refraction were 68 years (SD=4.7) and +0.55 D (SD=2.14), respectively. Pointwise statistical significance was obtained for rs1939008 (P-emp=0.0326). No SNP attained statistical significance after correcting for multiple testing. In stratified analyses, multiple SNPs reached pointwise significance in the lower-education group: 2 of these were statistically significant after multiple testing correction. The two highest-ranking SNPs in Amish families (rs1939008 and rs9928731) showed pointwise P-emp<0.01 in the lower-education stratum of AREDS participants. Conclusions We show suggestive evidence of replication of an association signal for ocular refraction to a marker between MMP1 and MMP10. We also provide evidence of a gene-environment interaction between previously-reported markers and education on refractive error. Variants in MMP1- MMP10 and MMP2 regions appear to affect population variation in ocular refraction in environmental conditions less favorable for myopia development.

Wojciechowski, Robert; Yee, Stephanie S.; Simpson, Claire L.; Bailey-Wilson, Joan E.; Stambolian, Dwight

2012-01-01

165

Rule based classifier for the analysis of gene-gene and gene-environment interactions in genetic association studies  

PubMed Central

Background Several methods have been presented for the analysis of complex interactions between genetic polymorphisms and/or environmental factors. Despite the available methods, there is still a need for alternative methods, because no single method will perform well in all scenarios. The aim of this work was to evaluate the performance of three selected rule based classifier algorithms, RIPPER, RIDOR and PART, for the analysis of genetic association studies. Methods Overall, 42 datasets were simulated with three different case-control models, a varying number of subjects (300, 600), SNPs (500, 1500, 3000) and noise (5%, 10%, 20%). The algorithms were applied to each of the datasets with a set of algorithm-specific settings. Results were further investigated with respect to a) the Model, b) the Rules, and c) the Attribute level. Data analysis was performed using WEKA, SAS and PERL. Results The RIPPER algorithm discovered the true case-control model at least once in >33% of the datasets. The RIDOR and PART algorithm performed poorly for model detection. The RIPPER, RIDOR and PART algorithm discovered the true case-control rules in more than 83%, 83% and 44% of the datasets, respectively. All three algorithms were able to detect the attributes utilized in the respective case-control models in most datasets. Conclusions The current analyses substantiate the utility of rule based classifiers such as RIPPER, RIDOR and PART for the detection of gene-gene/gene-environment interactions in genetic association studies. These classifiers could provide a valuable new method, complementing existing approaches, in the analysis of genetic association studies. The methods provide an advantage in being able to handle both categorical and continuous variable types. Further, because the outputs of the analyses are easy to interpret, the rule based classifier approach could quickly generate testable hypotheses for additional evaluation. Since the algorithms are computationally inexpensive, they may serve as valuable tools for preselection of attributes to be used in more complex, computationally intensive approaches. Whether used in isolation or in conjunction with other tools, rule based classifiers are an important addition to the armamentarium of tools available for analyses of complex genetic association studies.

2011-01-01

166

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

PubMed Central

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

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

2013-01-01

167

FPGA based time domain Passivity Observer and Passivity Controller  

Microsoft Academic Search

In this paper, field programmable gate array (FPGA) based time domain passivity observer and passivity controller is proposed to improve the stability range of haptic interfaces. A simplified PO\\/PC algorithm is implemented on FPGA for improving the control efficiency. Thanks to the fast sampling rate and the parallel processing ability of the FPGA, the PO\\/PC can be updated irregularly only

Beibei Han; Jee-Hwan Ryu; Il-Kyun Jung

2009-01-01

168

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

169

Passive cooling effects of courtyards  

Microsoft Academic Search

The passive cooling effects of a courtyard of a small building were determined numerically, employing an energy-analysis software developed for that purpose. The passive cooling features considered were the shading effects of courtyard walls and two large trees (of various shapes) planted immediately next to the south wall of the building, the presence of a pool, a lawn and flowers

H. Safarzadeh; M. N. Bahadori

2005-01-01

170

Passive Greenhouses and Ecological Reconstruction  

Microsoft Academic Search

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

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

2008-01-01

171

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

172

Passive retrofits for Navy housing  

SciTech Connect

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

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

1985-01-01

173

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

174

Passive Optical Networks (PONs)  

NSDL National Science Digital Library

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

Qaissaunee, Michael; Snyder, Gordon F.

2010-11-23

175

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

176

Small passive chemical detector  

SciTech Connect

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

Hong, K.C.

1992-03-26

177

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

178

Passive seismic experiment  

NASA Technical Reports Server (NTRS)

The design, deployment, and operation of the Apollo 16 passive seismic experiment (PSE) are discussed. Since activation, all elements of the PSE have operated as planned, with the exception of the sensor thermal control system. Significant progress in the measurement of meteoroid flux in near-earth space has been made, along with dilineation of active moonquake source regions. The data obtained indicate that moonquakes are concentrated at great depth (800 to 1000 km) and that the apparent disparity between meteoroid flux estimtes based on lunar crater counts and those from earth-based observations can be resolved by seismic measurements in favor of the lower flux indicated by the crater count method. The results obtained from the PSE are summarized and their significance is discussed in detail.

Latham, G. V.; Ewing, M.; Press, F.; Sutton, G.; Dorman, J.; Nakamura, Y.; Toksoz, N.; Lammlein, D.; Duennebier, F.

1972-01-01

179

The relationship between passive smoking and ovarian response outcome in ART cycles  

Microsoft Academic Search

Background: Smoking has negative effects on reproductive process. Exposing to cigarette smoking (passive smoking) may exert some effects as the direct smoking. Objective: The aim of this study was to evaluate the correlation between ovarian response and passive smoking in women who underwent ART cycles. Materials and Methods: One hundred-sixty patients who underwent ICSI between 2000 and 2001 were studied

Monir Owj; Moid Mohseni; Elham Amirchaghmaghi; Maria Sadeghi; Fatemeh Shabani

180

Passive-Solar-Heating Analysis: a new ASHRAE manual  

SciTech Connect

The forthcoming ASHRAE book, Passive Solar Heating Analysis, is described. ASHRAE approval procedures are discussed. An overview of the contents is given. The development of the solar load ratio correlations is described, and the applicability of the analysis method is discussed.

Balcomb, J.D.

1983-01-01

181

Galaxy Zoo: passive red spirals  

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

182

Passive thermosiphon solar collector  

SciTech Connect

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

Sullivan, J.W.

1984-01-01

183

Passive blast pressure sensor  

SciTech Connect

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

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

2013-03-19

184

Ecology of passive smoking by young infants.  

PubMed

This study provides a detailed description of passive smoking by 433 infants (mean age 18 days) enrolled from a representative population of healthy neonates in central North Carolina during 1986 and 1987. Sixty-four percent (276) lived in households with smokers or had contact with nonhousehold smokers. During the week before data collection, two thirds (184) of these 276 infants reportedly had tobacco smoke produced in their presence. Seventy-five percent of smoking mothers smoked near their infants. The amount smoked by the mother near the infant correlated with the amount smoked near the infant by nonmaternal smokers. Cotinine, an indicator of smoke absorption, was found in the urine of 60% (258) of all study infants. The amount smoked in the infant's presence, as well as the amount smoked farther away from the infant, especially by the mother, were the most significant correlates of the urine cotinine concentration. The results of this study suggest that efforts to reduce passive smoking in young infants should emphasize the importance of the mother's smoking behavior, smoke produced anywhere in the home, and household social influences on smoking behavior near the infant. PMID:2715891

Greenberg, R A; Bauman, K E; Glover, L H; Strecher, V J; Kleinbaum, D G; Haley, N J; Stedman, H C; Fowler, M G; Loda, F A

1989-05-01

185

Airborne Passive Target Motion Analysis.  

National Technical Information Service (NTIS)

Kalman filtering techniques are applied to a two sensor bearings only passive target motion analysis problem. An algorithm is developed to simulate tracking long range maneuvering airborne targets. The target tracking performance of the filter is evaluate...

J. A. Gutzler

1987-01-01

186

Enhanced Passive Thermal Propulsion System.  

National Technical Information Service (NTIS)

The long term goal is to advance our understanding of thermal energy extraction from the ocean thermocline using an enhanced passive thermal propulsion system. Integration of this new propulsion technology in a low drag hydrodynamic shape is expected to y...

D. Warner E. Warner

2008-01-01

187

Passive Explosion Barrier for Mines.  

National Technical Information Service (NTIS)

A passive explosion barrier is provided for use in mining operations in suppressing mine explosions. The barrier basically comprises a receptacle or tub which contains an explosion suppressing substance, such as water, and is mounted on a frame adjacent t...

I. Liebman R. Pro J. Corry

1979-01-01

188

Passive Scanning in Modbus Networks  

Microsoft Academic Search

This paper describes the design and implementation of a passive scanner for Modbus networks. The tool integrates packet parsing\\u000a and passive scanning functionality to interpret Modbus transactions and provide accurate network representations. In particular,\\u000a the scanner monitors Modbus messages to maintain and update state table entries associated with field devices. Entries in\\u000a the state tables record important information including function

Jesús González; Mauricio Papa

2007-01-01

189

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

190

A particle swarm optimizer with passive congregation  

Microsoft Academic Search

This paper presents a particle swarm optimizer (PSO) with passive congregation to improve the performance of standard PSO (SPSO). Passive congregation is an important biological force preserving swarm integrity. By introducing passive congregation to PSO, information can be transferred among individuals of the swarm. A particle swarm optimizer with passive congregation (PSOPC) is tested with a set of 10 benchmark

S. He; Q. H. Wu; J. Y. Wen; J. R. Saunders; R. C. Paton

2004-01-01

191

A system model for investigating passive electrical properties of neurons.  

PubMed Central

Passive membrane properties of neurons, characterized by a linear voltage response to constant current stimulation, were investigated by busing a system model approach. This approach utilizes the derived expression for the input impedance of a network, which simulates the passive properties of neurons, to correlate measured intracellular recordings with the response of network models. In this study, the input impedances of different network configurations and of dentate granule neurons, were derived as a function of the network elements and were validated with computer simulations. The parameters of the system model, which are the values of the network elements, were estimated using an optimization strategy. The system model provides for better estimation of the network elements than the previously described signal model, due to its explicit nature. In contrast, the signal model is an implicit function of the network elements which requires intermediate steps to estimate some of the passive properties.

D'Aguanno, A; Bardakjian, B L; Carlen, P L

1989-01-01

192

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

193

Materials for passively safe reactors  

SciTech Connect

Future nuclear power capacity will be based on reactor designs that include passive safety features if recent progress in advanced nuclear power developments is realized. There is a high potential for nuclear systems that are smaller and easier to operate than the current generation of reactors, especially when passive or intrinsic characteristics are applied to provide inherent stability of the chain reaction and to minimize the burden on equipment and operating personnel. Taylor, has listed the following common generic technical features as the most important goals for the principal reactor development systems: passive stability, simplification, ruggedness, case of operation, and modularity. Economic competitiveness also depends on standardization and assurance of licensing. The performance of passively safe reactors will be greatly influenced by the successful development of advanced fuels and materials that will provide lower fuel-cycle costs. A dozen new designs of advanced power reactors have been described recently, covering a wide spectrum of reactor types, including pressurized water reactors, boiling water reactors, heavy-water reactors, modular high-temperature gas-cooled reactors (MHTGRs), and fast breeder reactors. These new designs address the need for passive safety features as well as the requirement of economic competitiveness.

Simnad, T. (Univ. of California, San Diego, (United States))

1993-01-01

194

Correlation Algorithm: the Conceptual Framework.  

National Technical Information Service (NTIS)

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

L. G. Taff

1988-01-01

195

Determining Subsurface Structure From Microtremors Using a Passive Circular Array  

NASA Astrophysics Data System (ADS)

The amount of damage to a structure during an earthquake is related to the ground motion at that site. Therefore, it is important to study seismic waves that propagate through specific soil types to understand site response. However, active seismic surveys are susceptible to noise interference and are limited due to spatial need while boreholes are costly. We develop a method using a passive array to study Rayleigh waves from microtremors, waves originating from building appliances, cars, pedestrians walking, etc. By using everyday noises as the source, site-specific analysis can be done in urban areas without worrying about noise interference or disturbing the public with explosions or other loud active sources. The array is comprised of short period Texans, self contained geophones, which record continuously for 24 hours. Our technique differs slightly from traditional SPAC (SPatial Auto-Correlation) methods used in passive arrays. We first cross correlate time windows between two receivers then stack the correlations to determine a phase delay. Performing the correlation at different frequencies will create a dispersion curve that can be inverted for shear velocity. This approach is similar to the two-station phase delay method used in regional tomography studies at much longer periods. Stacking removes off-azimuth energy, so we do not need to assume a source direction. Preliminary results from a previous passive array survey conducted near El Paso, Texas show 1-D velocity models can be created by cross-correlating noise at various frequencies. We will conduct another survey in alluvium sands at Rio Bosque Park east of El Paso. We will validate the results with active seismic refraction and surface wave survey results as well as other geophysical techniques to determine if a passive array using microtremors is an accurate method of determining subsurface structure.

Folger, D. S.; Doser, D. I.; Velasco, A. A.

2005-12-01

196

Some Hazards of Passive Smoking  

PubMed Central

Non-smokers are exposed to three types of cigaret smoke: mainstream, sidestream and diffusional smoke, of which sidestream (produced while the cigaret smolders in an ashtray) is the most toxic. Studies of passive smoking show that while smoke is an unpleasant irritant, it appears to have no lasting effects on healthy passive smokers. It may, however, be a particular irritant to already sensitive individuals such as asthmatics, and to young children chronically exposed. Such children show an increase of respiratory disorders, and adults show an increase of small airway disease with a possible risk of lung cancer. More stringent legislation on smoking is desirable.

Shephard, Roy J.

1982-01-01

197

Indoor localization using passive RFID  

NASA Astrophysics Data System (ADS)

Radio frequency identification (RFID) systems based on passive tags are used successfully in a wide range of object identification applications. However, the increasing needs to meet new demands on applications of localization and tracking create a new field for evolution of the RFID technology. This paper presents the design, implementation, and evaluation of a cost-effective localization system for in-building usage that is able to localize objects that carry passive RFID tags. The RFID reading is performed by a single Reader and an array of directional antennas through multiplexing. Evaluation and experimental results from three localization algorithms based on RSSI are presented.

Vastianos, George E.; Kyriazanos, Dimitris M.; Segou, Olga E.; Mitilineos, Stelios A.; Thomopoulos, Stelios C. A.

2011-05-01

198

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

199

An Empirical Comparison of Meta-analysis and Mega-analysis of Individual Participant Data for Identifying Gene-Environment Interactions.  

PubMed

For analysis of the main effects of SNPs, meta-analysis of summary results from individual studies has been shown to provide comparable results as "mega-analysis" that jointly analyzes the pooled participant data from the available studies. This fact revolutionized the genetic analysis of complex traits through large GWAS consortia. Investigations of gene-environment (G×E) interactions are on the rise since they can potentially explain a part of the missing heritability and identify individuals at high risk for disease. However, for analysis of gene-environment interactions, it is not known whether these methods yield comparable results. In this empirical study, we report that the results from both methods were largely consistent for all four tests; the standard 1 degree of freedom (df) test of main effect only, the 1 df test of the main effect (in the presence of interaction effect), the 1 df test of the interaction effect, and the joint 2 df test of main and interaction effects. They provided similar effect size and standard error estimates, leading to comparable P-values. The genomic inflation factors and the number of SNPs with various thresholds were also comparable between the two approaches. Mega-analysis is not always feasible especially in very large and diverse consortia since pooling of raw data may be limited by the terms of the informed consent. Our study illustrates that meta-analysis can be an effective approach also for identifying interactions. To our knowledge, this is the first report investigating meta-versus mega-analyses for interactions. PMID:24719363

Sung, Yun Ju; Schwander, Karen; Arnett, Donna K; Kardia, Sharon L R; Rankinen, Tuomo; Bouchard, Claude; Boerwinkle, Eric; Hunt, Steven C; Rao, Dabeeru C

2014-04-01

200

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

PubMed Central

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

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

2010-01-01

201

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

202

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

PubMed Central

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

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

2013-01-01

203

Passive tracking with sensors of opportunity using passive coherent location  

Microsoft Academic Search

Passive coherent location (PCL), which uses the commercial signals as illuminators of opportunity, is an emerging technology in air defense systems. The advantages of PCL are low cost, low vulnerability to electronic counter measures, early detection of stealthy targets and low-altitude detection. However, limitations of PCL include lack of control over illuminators, poor bearing accuracy, time-varying sensor parameters and limited

Mahes Subramaniam; R. Tharmarasa; Mike McDonald; T. Kirubarajan

2008-01-01

204

Optical Correlation.  

National Technical Information Service (NTIS)

Coherent optical correlators, classified as spatial plane correlators, frequency plane correlators, and special reference correlators, are examined. Basic principles, advantages, and disadvantages are discussed, and comparisons made with incoherent correl...

J. A. Boden

1974-01-01

205

Localization of Passive Scalars in Random Fluids  

NASA Astrophysics Data System (ADS)

We study the localization of classical diffusing particles in a quenched disordered velocity field in connection with quantum localizations. In particular, we focus on the time-dependent spatial correlations of the passive scalars (density of particles). Through a combination of numerical and analytic techniques, we find extended eigenstates at the neighborhood of a special point in the spectrum, E_{c}, where a sublattice decomposition obtains. We then analyze the scaling behavior by a finite-size scaling technique and obtain the critical exponent v. We further interpret the Lyapunov exponents in the language of conformal field theory and determine both the exponents of the typical spatial decay of eigenstates in the critical phase and the conformal charge.

Wang, Zheng Jane

1996-08-01

206

Correlation of nitrogen dioxide with other traffic pollutants near a major expressway  

Microsoft Academic Search

Objectives: This study addresses three objectives: (1) to assess the correlation of NO2 to other ambient pollutants measured with passive samplers; (2) to explore peak traffic particulate matter air pollution correlations with passively measured NO2; and (3) to pilot an advanced mobile air pollution laboratory to supply supplementary information on correlations between NO2 and other air pollutants. Methods: Active and

Bernardo Beckermana; Michael Jerrettb; Jeffrey R Brookd; Dave K Vermae; Muhammad A Araine; Murray M Finkelsteine

207

Passive Optical Bathymetry with CAESAR.  

National Technical Information Service (NTIS)

In addition to experiments with passive optical bathymetry with Landsat-TM a new project 'CAESAR-bottom' has been started. Its main objective is to compare the accuracy of the estimated depth of CAESAR with those of Landsat-TM. If possible the method of d...

M. van der Laan

1991-01-01

208

Passive Parallel Automatic Minimalist Processing  

Microsoft Academic Search

Research for which the idea that many basic cognitive processes can be described as fast, parallel, and automatic is reviewed. Memory retrieval\\/decision processes have often been ignored in the cognitive literature. However, in some cases, computation- ally complex processes can be replaced with simple passive processes. Cue-dependent retrieval from memory provides a straightforward example of how encoding, memory, and retrieval

Roger Ratcliff; Gail McKoon

209

Passive oscillatory heat transport systems  

Microsoft Academic Search

An underdeveloped class of oscillatory passive heat transport cycles are discussed that have the potential to transport significantly higher heat loads than current heat pipes. Prototype cycles employing inferior working fluids have demonstrated transport of higher heat loads over significantly greater distances than similarly sized heat pipes (including CPLs and LHPs) employing ammonia. Most of the proposed cycles do not

Mark M. Weislogel

2002-01-01

210

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

211

Passive Shimming for Solenoidal Magnets.  

National Technical Information Service (NTIS)

The report shows how passive iron shims may be used to correct the field of a nearly uniform solenoidal magnet. From the theory which is developed in the appendices, it is shown that thin shell-like shims are preferred for a large volume of corrected fiel...

J. H. Coupland

1986-01-01

212

Adaptive passive velocity field control  

Microsoft Academic Search

Passive velocity field control (PVFC) was previously developed for mechanical systems which have strong coordination and must interact with the physical environment. Applications include teleoperated manipulators, contouring in machining and smart exercise machines. The methodology encodes tasks using time invariant desired velocity fields instead of the more traditional method of timed trajectories and guarantees that the closed loop system behave

Perry Y. Li; Minneapolis MN

1999-01-01

213

Robust Passive Piezoelectric Shunt Dampener  

Microsoft Academic Search

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

S. Behrens; A. J. Fleming; S. O. R. Moheimani

214

[Passive smoking--active killer].  

PubMed

Although still not perceived in this way, passive smoking is a public health issue of great importance. World Health Organization estimates that as a result of passive exposure to tobacco smoke each year 600,000 people die, of which 165,000 children. There are 33% of men, 35% of women and 40% of children who do not smoke, but are exposed to second hand smoke, and still only 11% of the world population is protected by adequate smoke-free legislation. Scientific literature provides evidence that passive exposure to tobacco smoke can result in numerous adverse health effects: asthma and allergies, respiratory infections and (middle) ear infections, cancers of various localization, accelerated atherosclerosis and cardiovascular diseases, retardation of growth and development in children, and in pregnancy it can lead to congenital anomalies and premature birth as well as lower body weight and length of the child. Certainly, the scariest consequence of all is sudden infant death syndrome, also called "death in the crib". Smoke-free policies have proven their effectiveness, but while implementing the laws, it is necessary to raise public awareness of the hazards of, both active and passive, exposure to tobacco smoke. PMID:24490334

Palavra, Irena Rojni?; Franeli?, Iva Pejnovi?; Milanovi?, Sanja Musi?; Pulji?, Kresimir

2013-01-01

215

Passive maser development at NRL  

SciTech Connect

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

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

1981-01-01

216

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

217

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

PubMed Central

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

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

2012-01-01

218

Passive margins through earth history  

NASA Astrophysics Data System (ADS)

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

Bradley, Dwight C.

2008-12-01

219

Interior Design for Passive Solar Homes.  

National Technical Information Service (NTIS)

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 p...

J. C. Breen

1981-01-01

220

Citric Acid Passivation of Stainless Steel.  

National Technical Information Service (NTIS)

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

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

2010-01-01

221

Mapping the Whole Internet with Passive Measurements.  

National Technical Information Service (NTIS)

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

B. Maggs

2012-01-01

222

Passivation Of High-Temperature Superconductors  

NASA Technical Reports Server (NTRS)

Surfaces of high-temperature superconductors passivated with native iodides, sulfides, or sulfates formed by chemical treatments after superconductors grown. Passivating compounds nearly insoluble in and unreactive with water and protect underlying superconductors from effects of moisture. Layers of cuprous iodide and of barium sulfate grown. Other candidate passivating surface films: iodides and sulfides of bismuth, strontium, and thallium. Other proposed techniques for formation of passivating layers include deposition and gas-phase reaction.

Vasquez, Richard P.

1991-01-01

223

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

224

The Passive in Technical and Scientific Writing.  

ERIC Educational Resources Information Center

Almost every discussion of technical or scientific writing style mentions the passive voice as a stylistic choice to avoid. However, the passive voice does have legitimate uses in technical and scientific writing--the problem is to define the appropriate or effective uses and the inappropriate or ineffective ones. An examination of passive voice…

Rodman, Lilita

225

Passive derivation of basic walker-assisted gait characteristics from measured forces and moments  

Microsoft Academic Search

This work describes a method that passively assesses basic walker-assisted gait characteristic, including heel strikes, toe-off events, as well as stride time, double support and right & left single support phases using only force-moment measurements from the walker's handles. The passively derived gait characteristics were validated against motion capture gait analysis and showed good correlations. This research is part of

M. Alwan; G. Wasson; P. Sheth; A. Ledoux; C. Huang

2004-01-01

226

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

227

Interior design for passive solar homes  

NASA Astrophysics Data System (ADS)

The increasing emphasis on refinement of passive solar systems 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 from 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 suitably of various interior elements.

Breen, J. C.

1981-07-01

228

Passive standoff detection of chemical warfare agents on surfaces.  

PubMed

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

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

2004-11-01

229

Using a passive alcohol sensor to detect legally intoxicated drivers.  

PubMed Central

OBJECTIVES. We examined whether a passive alcohol sensor could be used for mass screening of motorists to accurately and quickly detect drivers whose blood alcohol concentration exceeded a variety of levels often established as per se evidence of legal intoxication. METHODS. In a voluntary roadside survey, 1181 late-night drivers in Minnesota were interviewed. Breath measurements were taken with both a passive alcohol sensor and an evidentiary quality portable breath-test device. RESULTS. Measurements could be taken much more easily and quickly with the passive sensor, whose readings correlated very strongly (r = .87) with the evidentiary device. Moreover, for criterion blood alcohol concentration levels ranging from 100 mg/dL to 20 mg/dL, a large proportion of motorists could be accurately identified as being above or below the criterion, with relatively few false-negative or false-positive identifications. CONCLUSIONS. The use of passive alcohol sensors at sobriety checkpoints should allow motorists to be processed very quickly with minimal inconvenience. At the same time, detection of legally intoxicated motorists will probably be substantially increased and the general deterrent value of per se alcohol-impaired driving laws enhanced.

Foss, R D; Voas, R B; Beirness, D J

1993-01-01

230

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

PubMed Central

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

2013-01-01

231

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

PubMed Central

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

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

2011-01-01

232

PASSIVE TRANSFER OF TRANSPLANTATION IMMUNITY  

PubMed Central

Passive transfer of tritiated thymidine labeled lymphoid cells sensitized to homologous tissues into non-sensitized isologous hosts resulted in accelerated rejection of homologous skin grafts in the recipients. Despite 33 per cent label of the suspension, only rare labeled sensitized lymphoid cells could be found at the site of rejection. Passive transfer of sensitized lymphoid cells in millipore chambers implanted subcutaneously or intraperitoneally in non-sensitized isologous hosts resulted in accelerated homograft rejection in the recipients. Transfer of transplantation immunity could not be accomplished with serum from sensitized hosts. The rejection of homologous tissues without the physical presence of the sensitized cell at the graft site suggested that a humoral agent produced by the cell was capable of rejecting the homograft.

Najarian, John S.; Feldman, Joseph D.

1962-01-01

233

Passive Photonic Devices in Glass  

NASA Astrophysics Data System (ADS)

Femtosecond laser microfabrication offers the potential for writing passive photonic circuits inside bulk glasses, for use in last-mile photonic networks, sensing, and lab-on-a-chip applications. In this chapter, the fabrication methods for writing low-loss optical waveguides along with waveguide and device characterization techniques are reviewed. The advantages and disadvantages of femtosecond laser writing are analyzed and compared with existing planar lithographic fabrication techniques.

Eaton, Shane M.; Herman, Peter R.

234

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

2006-06-01

235

Evaluation of Alternate Surface Passivation Methods (U)  

SciTech Connect

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

Clark, E

2005-05-31

236

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

237

Functional Variants in the Catalase and Myeloperoxidase Genes, Ambient Air Pollution, and Respiratory-related School Absences: An Example of Epistasis in Gene-Environment Interactions  

PubMed Central

The individual effect of functional single nucleotide polymorphisms within the catalase and myeloperoxidase genes (CAT and MPO) has been studied in relation to asthma; however, their interrelationship with ambient air pollution exposures has yet to be determined. The authors investigated the interrelationships between variants in CAT and MPO, ambient air pollutants, and acute respiratory illness. Health information, air pollution, and incident respiratory-related school absences were ascertained in January–June 1996 for 1,136 Hispanic and non-Hispanic white US elementary schoolchildren as part of the prospective Children's Health Study. Functional and tagging single nucleotide polymorphisms for the CAT and MPO loci were genotyped. The authors found epistasis between functional polymorphisms in the CAT/MPO loci, which differed by levels of oxidant-stress-producing air pollutants. Risk of respiratory-related school absences was elevated for children with the CAT (G/G) and MPO (G/A or A/A) genes (relative risk?=?1.35, 95% confidence interval: 1.03, 1.77; P-interaction?=?0.005). The epistatic effect of CAT and MPO variants was most evident in communities exhibiting high ambient ozone levels (P-interaction?=?0.03). The association of respiratory-illness absences with functional variants in CAT and MPO that differ by air pollution levels illustrates the need to consider genetic epistasis in assessing gene-environment interactions.

Wenten, Made; Gauderman, W. James; Berhane, Kiros; Lin, Pi-Chu; Peters, John; Gilliland, Frank D.

2009-01-01

238

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

PubMed Central

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

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

2012-01-01

239

Evidence of Gene-Environment Interaction for the RUNX2 Gene and Environmental Tobacco Smoke in Controlling the Risk of Cleft Lip with/without Cleft Palate  

PubMed Central

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

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

2013-01-01

240

Genotype-Based Association Mapping of Complex Diseases: Gene-Environment Interactions with Multiple Genetic Markers and Measurement Error in Environmental Exposures  

PubMed Central

With the advent of dense single nucleotide polymorphism genotyping, population-based association studies have become the major tools for identifying human disease genes and for fine gene mapping of complex traits. We develop a genotype-based approach for association analysis of case-control studies of gene-environment interactions in the case when environmental factors are measured with error and genotype data are available on multiple genetic markers. To directly use the observed genotype data, we propose two genotype-based models: genotype effect and additive effect models. Our approach offers several advantages. First, the proposed risk functions can directly incorporate the observed genotype data while modeling the linkage disequihbrium information in the regression coefficients, thus eliminating the need to infer haplotype phase. Compared with the haplotype-based approach, an estimating procedure based on the proposed methods can be much simpler and significantly faster. In addition, there is no potential risk due to haplotype phase estimation. Further, by fitting the proposed models, it is possible to analyze the risk alleles/variants of complex diseases, including their dominant or additive effects. To model measurement error, we adopt the pseudo-likelihood method by Lobach et al. [2008]. Performance of the proposed method is examined using simulation experiments. An application of our method is illustrated using a population-based case-control study of association between calcium intake with the risk of colorectal adenoma development.

Lobach, Irvna; Fan, Ruzone; Carroll, Raymond T.

2011-01-01

241

A Comparison of Case-Control and Case-Only Designs to Investigate Gene-Environment Interactions Using Breast Cancer Data  

PubMed Central

Background: The traditional methods of studying the gene-environment interactions need a control group. However, the selection of an appropriate control group has been associated with problems. Therefore, new methods, such as case-only design, have been created to study such interactions. The objective of this study was to compare the case-only and case-control designs using data from patients with breast cancer. Methods: The interaction of genetic and environmental factor as well as the ratio of control to population odds ratio was calculated for case-only (300 patients with breast cancer) and case-control (300 cases of breast cancer and 300 matched controls) designs. Results: The confidence intervals and -2log likelihood in all variables in case-only design was smaller than those in the matched case-control design. In case-only design, the standard errors of some variables such as age at menarche, the first delivery at the age of 35 yrs and more or no delivery, the history of having live birth, use of oral contraception pills, breastfeeding history were less than those in the matched case-control design. Conclusion: The findings indicate that the case-only design is an efficient method to investigate the interaction of genetic and environmental factors.

Hassanzadeh, Jafar; Moradzadeh, Rahmatollah; Rajaee fard, Abdolreza; Tahmasebi, Sedigheh; Golmohammadi, Parvaneh

2012-01-01

242

Acute effects of passive stretching of the plantarflexor muscles on neuromuscular function: the influence of age.  

PubMed

The acute effects of stretching on peak force (F peak), percent voluntary activation (%VA), electromyographic (EMG) amplitude, maximum range of motion (MROM), peak passive torque, the passive resistance to stretch, and the percentage of ROM at EMG onset (%EMGonset) were examined in 18 young and 19 old men. Participants performed a MROM assessment and a maximal voluntary contraction of the plantarflexors before and immediately after 20 min of passive stretching. F peak (-11 %), %VA (-6 %), and MG EMG amplitude (-9 %) decreased after stretching in the young, but not the old (P?>?0.05). Changes in F peak were related to reductions in all muscle activation variables (r?=?0.56-0.75), but unrelated to changes in the passive resistance to stretch (P???0.24). Both groups experienced increases in MROM and peak passive torque and decreases in the passive resistance to stretch. However, the old men experienced greater changes in MROM (P?passive resistance (P?=?0.02-0.06). Changes in MROM were correlated to increases in peak passive torque (r?=?0.717), and the old men also experienced a nonsignificant greater (P?=?0.08) increase in peak passive torque. %EMGonset did not change from pre- to post-stretching for both groups (P?=?0.213), but occurred earlier in the old (P?=?0.06). The stretching-induced impairments in strength and activation in the young but not the old men may suggest that the neural impairments following stretching are gamma-loop-mediated. In addition, the augmented changes in MROM and passive torque and the lack of change in %EMGonset for the old men may be a result of age-related changes in muscle-tendon behavior. PMID:24981113

Ryan, Eric D; Herda, Trent J; Costa, Pablo B; Herda, Ashley A; Cramer, Joel T

2014-08-01

243

Determination of the passive absorption through the rat intestine using chromatographic indices and molar volume.  

PubMed

Immobilized artificial membrane (IAM) chromatography coupled to physicochemical descriptors was evaluated to model the passive intestinal absorption of drugs through rat gut sacs. The chromatographic capacity factors (logk'(IAM)) of 12 structurally diverse compounds were determined on a IAM PC DD2 column. The passive permeabilities (P(a)) of the drugs were determined through rat everted gut sacs or through non-everted sacs for actively transported molecules. Correlation studies between logk'(IAM), physicochemical descriptors and P(a) were conducted by stepwise multiple linear regression (MLR) and back-propagation neural network (BPNN). MLR and BPNN showed that logk'(IAM) was the descriptor which correlated best with P(a). Considering the molar volume as an additional descriptor, the correlation was improved. Retention indices on IAM and the molar volume can be used concurrently to predict passive drug absorption. PMID:11113641

Genty, M; González, G; Clere, C; Desangle-Gouty, V; Legendre, J Y

2001-01-01

244

The passive-aggressive organization.  

PubMed

Passive-aggressive organizations are friendly places to work: People are congenial, conflict is rare, and consensus is easy to reach. But, at the end of the day, even the best proposals fail to gain traction, and a company can go nowhere so imperturbably that it's easy to pretend everything is fine. Such companies are not necessarily saddled with mulishly passive-aggressive employees. Rather, they are filled with mostly well-intentioned people who are the victirms of flawed processes and policies. Commonly, a growing company's halfhearted or poorly thought-out attempts to decentralize give rise to multiple layers of managers, whose authority for making decisions becomes increasingly unclear. Some managers, as a result, hang back, while others won't own up to the calls they've made, inviting colleagues to second-guess or overturn the decisions. In such organizations, information does not circulate freely, and that makes it difficult for workers to understand the impact of their actions on company performance and for managers to correctly appraise employees' value to the organization. A failure to accurately match incentives to performance stifles initiative, and people do just enough to get by. Breaking free from this pattern is hard; a long history of seeing corporate initiatives ignored and then fade away tends to make people cynical. Often it's best to bring in an outsider to signal that this time things will be different. He or she will need to address every obstacle all at once: clarify decision rights; see to it that decisions stick; and reward people for sharing information and adding value, not for successfully negotiating corporate politics. If those steps are not taken, it's only a matter of time before the diseased elements of a passive-aggressive organization overwhelm the remaining healthy ones and drive the company into financial distress. PMID:16250627

Kaplan, Robert S; Norton, David P

2005-10-01

245

PASSIVE TRANSFER OF TRANSPLANTATION IMMUNITY  

PubMed Central

Passive transfer of homograft immunity was successfully achieved by injection of the supernatant obtained from tissue-sensitized lymphoid cells disrupted by sonic vibration. The effective substance destroyed specific skin homografts within 6 days but did not reject non-specific skin grafts in this time. No evidence of transferred antigen or of transfer factor was found when the effective material was passed to irradiated recipients carrying test grafts. By a variety of physiochemical procedures the "soluble substance" behaved like a gamma globulin and was considered to be a transplantation antibody.

Najarian, J. S.; Feldman, J. D.

1963-01-01

246

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

247

Passive Testing of Web Services  

NASA Astrophysics Data System (ADS)

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

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

248

Calibration of permeation passive samplers with silicone membranes based on physicochemical properties of the analytes.  

PubMed

Passive sampling is a very attractive alternative to active sampling due to its simplicity and low cost. Among the passive samplers used in air analysis, permeation passive samplers are the least affected by ambient conditions, including humidity, air currents, and temperature changes. The biggest drawback of permeation passive samplers is the need to calibrate them experimentally for each individual target analyte. The paper presents the results of research on the calibration of permeation passive samplers based on physicochemical properties of the analytes. Strong correlations were found between the calibration constants of the samplers and the number of carbon atoms among families of compounds (R2 ranging from 0.8507 for alcohols to 0.9995 for aromatic hydrocarbons), the molecular weights of the compounds (R2 = 0.8742), their boiling points (R2 = 0.8911), and linear temperature-programmed retention indexes (R2 = 0.9225). The last correlation makes it possible to estimate the calibration constants for unidentified analytes, which is impossible when the conventional procedure is used. This makes it possible to deploy permeation passive samplers in the same way in which active sampling is deployed. PMID:12964768

Zabiega?a, Bozena; Górecki, Tadeusz; Namie?nik, Jacek

2003-07-01

249

Differences In The Active and Passive Scalar Fluxes In Stably Stratified Turbulence  

NASA Astrophysics Data System (ADS)

Passive and active scalar (i.e., density) fluxes in unsteady stably stratified turbulence are analyzed using the rapid distortion theory (RDT) (e.g., Hanazaki & Hunt, 1996). Analytical solutions of the RDT equations show that the initial conditions, in par- ticular the initial correlations between the passive scalar and the active scalar, are important in determining the difference in the time development between the pas- sive and the active scalar fluxes. If there is initial correlation between the active and passive scalars, the passive scalar flux has the slowly oscillating components of half frequency N (N:Brunt-Vaisala frequency) compared to the usual frequency 2N of the active scalar (density) flux. Analysis in which the effects of diffusion coeeficients (Pr:active scalar, Sc:passive scalar) are considered show that, in the realistic conditions for which Pr<passive scalar fluxes becomes more pronounced at large times. The results helps explaining the recent DNS and ex- perimental results by Kaltenbach, Gerz & Schumann(1994) and Nagata & Komori (2001).

Hanazaki, H.; Miyazaki, T.

250

The contribution of active and passive leisure to children's well-being.  

PubMed

The relation between leisure and well-being, including happiness and self-concept, was examined in 375 children aged 8-12 years. Active leisure (e.g. physical activity) was positively correlated with well-being. Passive leisure (e.g. television and video games) was negatively correlated with well-being. Aspects of active leisure (e.g. the importance of sport to the child and how sports made the child feel) as judged by both parents and children accounted for unique variance in children's wellbeing; passive leisure did not. Similar to previous research on adolescents and adults, active leisure activities were related to children's well-being. PMID:19293299

Holder, Mark D; Coleman, Benjamin; Sehn, Zoë L

2009-04-01

251

Gap between active and passive solar heating  

SciTech Connect

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

Balcomb, J.D.

1985-01-01

252

Passive cigarette smoking increases isoprostane formation  

Microsoft Academic Search

Passive smoking has been demonstrated to exert a variety of deleterious effects eventually resulting in vascular damage. Isoprostanes, a reliable marker of in vivo oxidation injury, have been shown to increase in active cigarette smoking. Data for passive smoking are lacking. We were examining the isoprostane 8-epi-PGF2? in 12 smokers and non-smokers exposed daily to passive cigarette smoke for 12

Hossein Ahmadzadehfar; Anthony Oguogho; Yannis Efthimiou; Harald Kritz; Helmut Sinzinger

2006-01-01

253

Hydrogen passivation of multicrystalline silicon solar cells  

Microsoft Academic Search

The use of hydrogen for passivation of multicrystalline silicon in solar cell technology is described. Three kinds of hydrogen incorporation into mc-Si solar cells have been evaluated: hydrogen diffusion out of a SiN-layer (SiN:H), low-energy hydrogen ion implantation (HII), and remote plasma hydrogen passivation (RPHP). Best results were obtained by RPHP, whereas using HII, damage exceeded the passivation effect to

Ralf Lüdemann

1999-01-01

254

Time course of changes in passive properties of the gastrocnemius muscle-tendon unit during 5 min of static stretching.  

PubMed

The minimum time required for Static stretching (SS) to change the passive properties of the muscle-tendon unit (MTU), as well as the association between these passive properties, remains unclear. This study investigated the time course of changes in the passive properties of gastrocnemius MTU during 5 min of SS. The subjects comprised 20 healthy males (22.0 ± 1.8 years). Passive torque as an index of MTU resistance and myotendinous junction (MTJ) displacement as an index of muscle extensibility were assessed using ultrasonography and dynamometer during 5 min of SS. Significant differences before and every 1 min during SS were determined using Scheffé's post hoc test. Relationships between passive torque and MTJ displacement for each subject were determined using Pearson's product-moment correlation coefficient. Although gradual changes in both passive torque and MTJ displacement were demonstrated over every minute, these changes became statistically significant after 2, 3, 4, and 5 min of SS compared with the values before SS. In addition, passive torque after 5 min SS was significantly lower than that after 2 min SS. Similarly, MTJ displacement after 5 min SS was significantly higher than that after 2 min SS. A strong correlation was observed between passive torque and MTJ displacement for each subject (r = -0.886 to -0.991). These results suggest that SS for more than 2 min effectively increases muscle extensibility, which in turn decreases MTU resistance. PMID:23294911

Nakamura, Masatoshi; Ikezoe, Tome; Takeno, Yohei; Ichihashi, Noriaki

2013-06-01

255

Passive cavitation imaging with ultrasound arrays  

PubMed Central

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

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

2009-01-01

256

Effects of isokinetic passive exercise and isometric muscle contraction on passive stiffness.  

PubMed

[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

2013-10-01

257

The effect of UGT1A and UGT2B polymorphisms on colorectal cancer risk: haplotype associations and gene–environment interactions.  

PubMed

UDP-glucuronosyltransferases (UGTs) play an important role in the phase II metabolism of exogenous and endogenous compounds. As colorectal cancer (CRC) etiology is thought to involve the biotransformation of dietary factors, UGT polymorphisms may affect CRC risk by altering levels of exposure. Genotyping of over 1800 Caucasian subjects was completed to identify the role of genetic variation in nine UGT1A and five UGT2B genes on CRC risk. Unconditional logistic regression and haplotype analyses were conducted to identify associations with CRC risk and potential gene-environment interactions. UGT1A haplotype analysis found that the T-G haplotype in UGT1A10 exon 1 (block 2: rs17864678, rs10929251) decreased cancer risk for the colon [proximal (OR?=?0.28, 95% CI?=?0.11–0.69) and for the distal colon (OR?=?0.32, 95% CI?=?0.12–0.91)], and that the C-T-G haplotype in the 3? region flanking the UGT1A shared exons (block 11: rs7578153, rs10203853, rs6728940) increased CRC risk in males (OR?=?2.56, 95% CI?=?1.10–5.95). A haplotype in UGT2B15 containing a functional variant (rs4148269, K523T) and an intronic SNP (rs6837575) was found to affect rectal cancer risk overall (OR?=?2.57, 95% CI?=?1.21–5.04) and in females (OR?=?3.08, 95% CI?=?1.08–8.74). An interaction was found between high NSAID use and the A-G-T haplotype (block 10: rs6717546, rs1500482, rs7586006) in the UGT1A shared exons that decreased CRC risk. This suggests that UGT genetic variation alters CRC risk differently by anatomical sub-site and gender and that polymorphisms in the UGT1A shared exons may have a regulatory effect on gene expression that allows for the protective effect of NSAIDs on CRC risk. PMID:24822274

Angstadt, Andrea Y; Hartman, Terryl J; Lesko, Samuel M; Muscat, Joshua E; Zhu, Junjia; Gallagher, Carla J; Lazarus, Philip

2014-06-01

258

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

259

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

260

Impact of variation in the BDNF gene on social stress sensitivity and the buffering impact of positive emotions: replication and extension of a gene-environment interaction.  

PubMed

A previous study reported that social stress sensitivity is moderated by the brain-derived-neurotrophic-factor(Val66Met) (BDNF rs6265) genotype. Additionally, positive emotions partially neutralize this moderating effect. The current study aimed to: (i) replicate in a new independent sample of subjects with residual depressive symptoms the moderating effect of BDNF(Val66Met) genotype on social stress sensitivity, (ii) replicate the neutralizing impact of positive emotions, (iii) extend these analyses to other variations in the BDNF gene in the new independent sample and the original sample of non-depressed individuals. Previous findings were replicated in an experience sampling method (ESM) study. Negative Affect (NA) responses to social stress were stronger in "Val/Met" carriers of BDNF(Val66Met) compared to "Val/Val" carriers. Positive emotions neutralized the moderating effect of BDNF(Val66Met) genotype on social stress sensitivity in a dose-response fashion. Finally, two of four additional BDNF SNPs (rs11030101, rs2049046) showed similar moderating effects on social stress-sensitivity across both samples. The neutralizing effect of positive emotions on the moderating effects of these two additional SNPs was found in one sample. In conclusion, ESM has important advantages in gene-environment (GxE) research and may attribute to more consistent findings in future GxE research. This study shows how the impact of BDNF genetic variation on depressive symptoms may be explained by its impact on subtle daily life responses to social stress. Further, it shows that the generation of positive affect (PA) can buffer social stress sensitivity and partially undo the genetic susceptibility. PMID:24613654

van Winkel, Mark; Peeters, Frenk; van Winkel, Ruud; Kenis, Gunter; Collip, Dina; Geschwind, Nicole; Jacobs, Nele; Derom, Catherine; Thiery, Evert; van Os, Jim; Myin-Germeys, Inez; Wichers, Marieke

2014-06-01

261

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

262

ARTICLES: Polymer passive Q switch  

NASA Astrophysics Data System (ADS)

A study was made of polymer passive Q switches made of polyurethane acrylate colored with a dithiobenzyl complex of nickel. These switches were designed for the use in YAG:Nd3+ lasers. The polymer employed in these switches was elastic in a wide range of temperatures (beginning from -30°C), it adhered well to glass surfaces of the optical grade, and had a high optical strength. The layer structure of these switches improved the transfer of heat from the polymer to the substrate, the thermal conductivity of which was higher, so that the switches could operate stably at radiation intensities up to 16 W/cm2 without any need to move the switch. The photochemical stability of the dye in polyurethane acrylate was 106 pulses at a given point. When the resonator length was reduced to 6 cm and the active element was YAG:Nd3+ , the duration of the single pulses generated using a passive Q switch of this type was ~0.5 nsec and the divergence did not exceed 1 mrad (the corresponding half-width of the beam in the near-field zone was 1.5 mm).

Bezrodny?, V. I.; Tikhonov, E. A.

1986-12-01

263

Passive locomotion in unsteady flows  

NASA Astrophysics Data System (ADS)

The passive locomotion of a submerged body in unsteady flow is studied. This work is motivated by recent experimental evidence that live and dead trout exploit vortices in the wake of an oscillating cylinder to swim upstream. We consider a simple model of a rigid body interacting dynamically with idealized wake models. The wake models consist of point vortices periodically introduced into the fluid domain to emulate shedding of vortices from an external un-modeled fixed or moving obstacle producing a "drag" or "thrust" wake, respectively. Both symmetric and staggered vortex configurations are considered. The submerged body is free to move in the plane, that is to say, it is not pinned at a given point. We do not prescribe a background flow, we rather consider the two-way coupled dynamics between the body's motion and the advection of ambient vortices. We show that both circular and elliptical bodies could "swim" passively against the flow by extracting energy from the ambient vortices. We obtain periodic trajectories for the body-vortex system and analyze their linear stability. We propose active feedback control strategies to overcome the instabilities.

Ghaemi Oskouei, Babak; Kanso, Eva

2010-11-01

264

Photoelectrochemistry of disordered passive films  

SciTech Connect

A theoretical model, which describes subband gap photoexcitation involving localized electronic states, was developed. The escape probability of a charge carrier trapped in a localized state is considered via Poole-Frenkel, direct tunneling, or phonon-assisted tunneling processes, as competing escape mechanisms. Photoelectrochemical experiments were performed on the passive films formed on zirconium and amorphous iron-zirconium alloys and on pure HfO/sub 2/ films and HfO/sub 2/ films implanted with varying concentrations of xenon. These films were found to possess some degree of disorder depending on the substrate, the thickness of the film, and the extent of implantation. The spectral dependence of the photocurrent in all of the films studied is considerably different from what was found for crystalline passive films. The potential dependence of the photocurrent yields Poole-Frenkel behavior. Reverse tunneling processes were also observed at low photon energies and low fields across the film, which is consistent with the theoretical results.

Newark, A.R.

1987-01-01

265

Passive tracking with sensors of opportunity using passive coherent location  

NASA Astrophysics Data System (ADS)

Passive coherent location (PCL), which uses the commercial signals as illuminators of opportunity, is an emerging technology in air defense systems. The advantages of PCL are low cost, low vulnerability to electronic counter measures, early detection of stealthy targets and low-altitude detection. However, limitations of PCL include lack of control over illuminators, poor bearing accuracy, time-varying sensor parameters and limited observability. In this paper, multiple target tracking using PCL with high bearing error is considered. In this case, the challenge is to handle high nonlinearity due to high measurement error. In this paper, we implement the converted measurement Kalman filter, unscented Kalman filter and particle filter based PHD filter for PCL radar measurements and compare their performances.

Subramaniam, Mahes; Tharmarasa, R.; McDonald, Mike; Kirubarajan, T.

2008-05-01

266

Passive optical star systems for fiber optic local area networks  

Microsoft Academic Search

Passive star topology and fiber-optic passive star systems are described. Technologies for passive star local area network (LAN) systems and their installation are discussed. It is contended that passive optical star systems represent an attractive and versatile architecture for implementation of many fiber-optic LANs, and that passive star topology best achieves the system goals of versatility, reliability, noise immunity, and

FREDERICK W. SCHOLL; MICHAEL H. CODEN

1988-01-01

267

General Corrosion and Passive Film Stability  

SciTech Connect

This report summarizes both general corrosion of Alloy 22 from 60 to 220 C and the stability of the passive (oxide) film from 60 to 90 C over a range of solution compositions that are relevant to the in-drift chemical environment at the waste package surface. The general corrosion rates were determined by weight-loss measurements in a range of complex solution compositions representing the products of both the evaporation of seepage water and also the deliquescence of dust previously deposited on the waste canisters. These data represent the first weight-loss measurements performed by the program at temperatures above 90 C. The low corrosion rates of Alloy 22 are attributed to the protective oxide film that forms at the metal surface. In this report, changes in the oxide film composition are correlated with weight loss at the higher temperatures (140-220 C) where film characterization had not been previously performed. The stability of the oxide film was further analyzed by conducting a series of electrochemical tests in progressively more acidic solutions to measure the general corrosion rates in solutions that mimic crevice or pit environments.

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

2005-07-19

268

Passive-solar multi-family concepts  

NASA Astrophysics Data System (ADS)

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

1981-08-01

269

SAW devices as wireless passive sensors  

Microsoft Academic Search

Surface acoustic wave (SAW) radio sensors make it possible to read measurement values from a remote location. The decisive advantage of these SAW sensors lies in their passive operation with no need for a separate power supply, and in the possibility of wireless installation at particularly inaccessible locations. The passive SAW sensors are maintenance free. The physical or chemical properties

L. Reindl; G. Scholl; T. Ostertag; C. C. W. Ruppel; W.-E. Bulst; F. Seifert

1996-01-01

270

Modeling Universal Relationships in Passive Sentences.  

ERIC Educational Resources Information Center

In the past, linguistic descriptions of the relationships common to passive sentences have not been universally applicable. Junction grammar, a type of generative grammar, is a model that may provide a means of describing universal passive relationships. Junction grammar differs from transformational grammar in that its rules (1) claim other…

Luthy, Melvin J.

271

Energy analysis of a passive solar system  

Microsoft Academic Search

This work aims at presenting the numerical solution to a natural convection problem concerning the use of a passive solar system for building heating purpose. The system consists of a modification of the well-known Trombe-Michel passive system. The main differences consist of thermal insulation on the southern wall surface, the presence of two solar ducts separated by a thin metallic

Luca Buzzoni; Roberto Dall'Olio; Marco Spiga

1998-01-01

272

Implementing a passive network covert timing channel  

Microsoft Academic Search

The paper concerns passive network covert timing channels, in which the channel senders reside in intermediate nodes (e.g. router, gateway) and forward the passing-by packets in a carefully planned manner to covertly transmit the information. In this study, we focus on constructing and testing a kind of passive network covert timing channel, in which the information is hidden in the

Xiaochao Zi; Lihong Yao; Li Pan; Jianhua Li

2010-01-01

273

Gap Between Active and Passive Solar Heating.  

National Technical Information Service (NTIS)

The gap between active and passive solar could hardly be wider. The reasons for this are discussed and advantages to narrowing the gap are analyzed. Ten years of experience in both active and passive systems are reviewed, including costs, frequent problem...

J. D. Balcomb

1985-01-01

274

Passive Safety Features for Small Modular Reactors  

Microsoft Academic Search

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

Daniel T

2010-01-01

275

Passive behaviour of zirconium, hafnium and niobium.  

National Technical Information Service (NTIS)

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

S. Hornkjoel

1990-01-01

276

Performance evaluation of passive DMFC single cells  

Microsoft Academic Search

Passive direct methanol fuel cells have been extensively investigated for the effects of methanol concentration, catalyst loading of electrodes, fuel and oxidant supply modes and long-term operation on their performance. Passive cells to which the reactants, methanol and air, are supplied by natural convection flow without the help of any external devices, have shown very different behavior compared with an

Byungchan Bae; Beck Kyun Kho; Tae-Hoon Lim; In-Hwan Oh; Seong-Ahn Hong; Heung Yong Ha

2006-01-01

277

Passive-Solar Manufactured Housing. Final Report.  

National Technical Information Service (NTIS)

Three model homes were developed. An existing model was modified to optimize the direct gain passive solar contribution without using new materials and with little or no added cost. A new model uses new design concepts to increase the direct gain passive ...

1980-01-01

278

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...

279

Passive Phase Noise Cancellation Scheme  

PubMed Central

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.

2013-01-01

280

Passive Tracking System and Method  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

281

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

282

A Passive Magnetic Bearing Flywheel  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

283

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

284

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

285

Addressing Passive Smoking in Children  

PubMed Central

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

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

2014-01-01

286

Integrated passive-solar demonstration project  

NASA Astrophysics Data System (ADS)

The objectives were to collect data on a combination of several passive solar heating and cooling systems. A passive solar test structure was constructed and monitored and the demonstration of passive systems designed into the structure was evaluated. Passive solar cooling principles include: shading all mass walls and windows from direct solar gain, maintaining cool attic and ceiling temperatures using solar induced ventilation, maintaining cool mean radiant wall temperatures, recirculating internal air, and using natural cross-ventilation through the conditioned space in spring and fall. Passive solar heating principles include: orientation of windows and sunspaces towards the south, providing double pane south windows, providing a double pane solar sunspace, using night insulation over glazing, extended thermal storge mass, and using a fan-forced rock/earth/air storage system.

Garrison, M. L.

1982-09-01

287

Passive microwave tags : LDRD 52709, FY04 final report.  

SciTech Connect

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

Brocato, Robert Wesley

2004-10-01

288

Passive remote detection of atmospheric pollutants using Fourier transform infrared (FTIR) spectroscopy  

Microsoft Academic Search

Feasibility studies on the use of passive FTIR spectroscopy for the remote detection of atmospheric pollutants have shown that gases may be identified remotely with an optically modified commercial FTIR spectrometer when only a small 7 degree(s)C) temperature difference exists between the gas and a background IR emitter. A correlation technique was used to extract information from noisy (SNR on

Moira Hilton; Alan H. Lettington; Ian M. Mills

1994-01-01

289

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.

2014-01-01

290

Differences in the passive and active scalar diffusion in stratified turbulence  

NASA Astrophysics Data System (ADS)

Turbulent fluxes of passive and active scalars in unsteady stratified homogeneous turbulence are analyzed using the rapid distortion theory(RDT). Analytical solutions of the RDT equations demonstrate that the initial conditions, i.e., the initial correlation between passive scalar and active scalar (density), and the initial potential energy, make difference between the passive and active scalar flux, giving difference between the turbulent diffusion coefficients for passive and active scalars. The difference appears in the passive scalar flux in its components slowly oscillating at frequency N (N: Brunt-Vaisala frequency), while the active scalar flux has only the twice as rapidly oscillating components with frequency 2N. Above results suggests the importance of the `unsteadness' and the `initial conditions'. Effects of molecular diffusion of pasive scalar (Schmidt number Sc) and density (Prandtl number Pr) show that if Sc>2/(1+1/Pr), the slowly oscillating mode with half frequency N decays more slowly than the fast mode with frequency 2N. Then the difference between the passive and active scalar fluxes would become significant in a long time.

Hanazaki, Hideshi

2004-11-01

291

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

292

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

293

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

294

[Passive euthanasia and living will].  

PubMed

This article deals with the notional 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 medicine, when e.g. giving pain-killer morphin to the patient, might result in shrinking 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 notary 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 notifies the hospital. Orv. Hetil., 2014, 155(27), 1057-1062. PMID:24974840

Julesz, Máté

2014-07-01

295

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

296

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

297

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

298

Reliability of reflectance measures in passive filters  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

299

Passive-Solar Multi-Family Concepts.  

National Technical Information Service (NTIS)

Seven designs for passive solar apartment/townhouse buildings are presented. Each design is briefly described and thoroughly illustrated. The buildings are sited in Indiana, Michigan, Missouri, Ohio, South Dakota, and Minnesota. (ERA citation 06:034606)

1981-01-01

300

Time-Frequency Cardiac Passive Acoustic Localization.  

National Technical Information Service (NTIS)

In a previous work, the authors have used a novel, radically different approach based on concurrent multi-sensor array measurements and 'super-resolution' array processing scheme for phonocardiographic signals. Using a specially designed passive acoustic ...

Y. Bahadirlar H. O. Gulcur

2001-01-01

301

Harmonic scattering from passive UHF RFID tags  

Microsoft Academic Search

This paper discusses harmonic scattering from passive UHF RFID tags. We describe the problem and the basic theory; explain our measurement setup, and present experimental results for three different commercial Gen2 tags.

Pavel V. Nikitin; K. V. S. Rao

2009-01-01

302

Observability in passive target motion analysis  

Microsoft Academic Search

The nature of observability of nonlinear systems encountered in passive target motion analysis (TMA) is carefully examined. The approach proposed here is based upon a well-chosen criterion which allows us to answer the major observability questions

C. Jauffret; D. Pillon

1996-01-01

303

Passive Techniques for Manipulating Field Soil Temperatures.  

National Technical Information Service (NTIS)

Recent concerns about global climate change have focused attention on the methodology for manipulating field soil temperatures. The objective of this study was to evaluate several simple, inexpensive, passive systems for changing soil surface temperature ...

G. M. Marion D. E. Pidgeon

1992-01-01

304

HTSC Microbolometer for Passive MMW Imaging Applications.  

National Technical Information Service (NTIS)

High temperature superconductor (HTSC) microbolometers are highly sensitive thermal detectors that can be miniaturized for affordable passive millimeter-wave (MMW) imaging. When coupled to a micro-antenna and built into an imaging system, they are most pr...

D. Potrepka D. Wikner E. Zakar M. Dubey S. Tidrow

2006-01-01

305

Lipid-Based Passivation in Nanofluidics  

PubMed Central

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

2012-01-01

306

Passive Earth Entry Vehicle Energy Absorbing Systems  

NASA Astrophysics Data System (ADS)

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

Kellas, S.; Maddock, R. W.

2014-06-01

307

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

308

Passive DF, a Tutorial. Part 1.  

National Technical Information Service (NTIS)

This memo introduces passive intercept and emitter identification problems. Then precission Direction of Arrival (DOA) methods and algorithms are introduced. The algorithms for amplitude comparison and phase interferometry are discussed in detail. Four ot...

B. Buckles

1987-01-01

309

A Microfluidic Passive Pumping Coulter Counter  

PubMed Central

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

McPherson, Amy L.; Walker, Glenn M.

2013-01-01

310

Apparatus for Locating Passive Intermodulation Interference Sources.  

National Technical Information Service (NTIS)

An apparatus for locating passive interference sources by using a pair of different RF signals in conjunction with an acoustic signal to generate intermodulation products in metal-to-metal junctions. The acoustic tagging technique utilizes a focused, high...

J. C. Mantovani

1985-01-01

311

Modeling of High Capacity Passive Cooling System.  

National Technical Information Service (NTIS)

High capacity passive cooling system studied in this project utilizes the thermoloop heat transfer concept (THTC). This device is an assemblage of Evaporator, Condenser, Non-return valves and Reservoir charged with a liquid for removing heat from any sour...

A. Islam

2009-01-01

312

Environmentally Dependent Countermeasures to Passive Infrared Detection.  

National Technical Information Service (NTIS)

Simple countermeasures against passive (thermal) infrared intrusion detection systems (IDSs) and thermal imagers were tested in winter by U.S. Army Special Forces soldiers working with personnel of the U. S. Army Cold Regions Research and Engineering Labo...

L. Peck J. Lacombe

1998-01-01

313

Passivity-Based Control of Electric Machines.  

National Technical Information Service (NTIS)

This doctoral thesis presents new results on the design and analysis of controllers for a class of electric machines. Nonlinear controllers are derived from a Lagrangian model representation using passivity techniques, and previous results on induction mo...

P. J. Nicklasson

1996-01-01

314

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

315

Superadditive correlation  

SciTech Connect

The fact that correlation does not imply causation is well known. Correlation between variables at two sites does not imply that the two sites directly interact, because, e.g., correlation between distant sites may be induced by chaining of correlation between a set of intervening, directly interacting sites. Such {open_quotes}noncausal correlation{close_quotes} is well understood in statistical physics: an example is long-range order in spin systems, where spins which have only short-range direct interactions, e.g., the Ising model, display correlation at a distance. It is less well recognized that such long-range {open_quotes}noncausal{close_quotes} correlations can in fact be stronger than the magnitude of any causal correlation induced by direct interactions. We call this phenomenon superadditive correlation (SAC). We demonstrate this counterintuitive phenomenon by explicit examples in (i) a model spin system and (ii) a model continuous variable system, where both models are such that two variables have multiple intervening pathways of indirect interaction. We apply the technique known as decimation to explain SAC as an additive, constructive interference phenomenon between the multiple pathways of indirect interaction. We also explain the effect using a definition of the collective mode describing the intervening spin variables. Finally, we show that the SAC effect is mirrored in information theory, and is true for mutual information measures in addition to correlation measures. Generic complex systems typically exhibit multiple pathways of indirect interaction, making SAC a potentially widespread phenomenon. This affects, e.g., attempts to deduce interactions by examination of correlations, as well as, e.g., hierarchical approximation methods for multivariate probability distributions, which introduce parameters based on successive orders of correlation. {copyright} {ital 1999} {ital The American Physical Society}

Giraud, B.G. [Service de Physique Theorique, Centre dEtudes de Saclay, 91191 Gif-sur-Yvette (France)] [Service de Physique Theorique, Centre dEtudes de Saclay, 91191 Gif-sur-Yvette (France); Heumann, J.M. [Hewlett Packard Company, Manufacturing Test Division, P.O. Box 301, Loveland, Colorado 80539-0301 (United States)] [Hewlett Packard Company, Manufacturing Test Division, P.O. Box 301, Loveland, Colorado 80539-0301 (United States); Lapedes, A.S. [Theoretical Division, Los Alamos National Laboratory, The Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, New Mexico 87501 (United States)] [Theoretical Division, Los Alamos National Laboratory, The Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, New Mexico 87501 (United States)

1999-05-01

316

Antimony Passivation of InP  

Microsoft Academic Search

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

Hajime Nobusawa; Hideaki Ikoma

1993-01-01

317

Passivity enforcement via perturbation of Hamiltonian matrices  

Microsoft Academic Search

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

S. Grivet-Talocia

2004-01-01

318

Energy savings obtainable through passive solar techniques  

SciTech Connect

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

Balcomb, J.D.

1980-01-01

319

Type II interferon induction and passive transfer depress the murine cytochrome P-450 drug metabolism system.  

PubMed Central

Induction of type II interferon by sensitization of mice with Mycobacterium tuberculosis strain BCG and challenge with tuberculin resulted in a depression of the cytochrome P-450 drug metabolism system of the liver. The degree of depression was significantly greater than in mice that were only sensitized to BCG. Cytochrome b5 levels were not affected. In addition, the level of the depression of the cytochrome P-450 system correlated with the levels of type II interferon induced. Passive transfer of exogenous type II interferon preparations also significantly depressed the cytochrome P-450 system. Passive transfer of mock interferon or of normal serum had no effect.

Sonnenfeld, G; Harned, C L; Thaniyavarn, S; Huff, T; Mandel, A D; Nerland, D E

1980-01-01

320

Passivity of corrosion-resistant alloys in environments containing chloride and hydrogen sulfide  

SciTech Connect

Passivity of corrosion-resistance alloys (CRA) in chloride (Cl{sup {minus}}) + hydrogen sulfide (H{sub 2}S) environments was investigated electrochemically to clarify the role of alloying elements. Pitting potential (V{prime}c) was correlated with alloying elements of Ni, Cr, and Mo. Ni was shown ineffective in improving pitting resistance in Cl{sup {minus}} environments. Passivity in Cl{sup {minus}} + H{sub 2}S environments was discussed based upon Auger electron spectroscopy (AES) analysis, and the roles of each alloying element were clarified.

Denpo, K.; Ogawa, H. [Nippon Steel Corp., Futtsu, Chiba (Japan). Pipe and Tube Steel Research Labs.

1997-09-01

321

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

322

Hydrogen in silicon: current understanding of diffusion and passivation mechanisms  

Microsoft Academic Search

A model for H diffusion and passivation is described that explains the experimental results from solar cell passivation, such as variations in the degree of passivation in substrates from different vendors, passivation due to forming gas anneals following Al alloying, and the effects of plasma enhanced chemical vapor deposition (PECVD) nitridation. Two major features of the model are inclusion of:

B. L. Sopori; X. Deng; J. P. Benner; A. Rohatgi; P. Sana; S. K. Estreicher; Y. K. Park; M. A. Roberson

1994-01-01

323

The Construal of Events: Passives in American Sign Language.  

ERIC Educational Resources Information Center

Outlines basic functions of passive constructions in language in general, and describes in more detail what form this takes in a proposal of American Sign Language (ASL). Compares discourse examples of active and passive constructions in ASL, addresses the role of topicalization in passive constructions, and discusses passives and reference…

Janzen, Terry; O'Dea, Barbara; Shaffer, Barbara

2001-01-01

324

Sorption cooling: A valid extension to passive cooling  

Microsoft Academic Search

Passive cooling has shown to be a very dependable cryogenic cooling method for space missions. Several missions employ passive radiators to cool down their delicate sensor systems for many years, without consuming power, without exporting vibrations or producing electromagnetic interference. So for a number of applications, passive cooling is a good choice. At lower temperatures, the passive coolers run into

D. J. Doornink; J. F. Burger; H. J. M. ter Brake

2008-01-01

325

Sorption cooling: a valid extension to passive cooling  

Microsoft Academic Search

Passive cooling has shown to be a very dependable cryogenic cooling method for space missions. Several missions employ passive radiators to cool down their delicate sensor systems for many years, without consuming power, without exporting vibrations or producing electromagnetic interference. So for a number of applications, passive cooling is a good choice. At lower temperatures, the passive coolers run into

Jan Doornink; Johannes Burger; Marcel ter Brake

2007-01-01

326

Coherent optical pulse CDMA systems based on coherent correlation detection  

Microsoft Academic Search

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

Wei Huang; Ivan Andonovic

1999-01-01

327

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

PubMed

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

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

2014-05-01

328

Discreet passive explosive detection through 2-sided waveguided fluorescence  

SciTech Connect

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

Harper, Ross James (Stillwater, OK); la Grone, Marcus (Cushing, OK); Fisher, Mark (Stillwater, OK)

2011-10-18

329

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

330

The Passive Film on Alloy 22  

SciTech Connect

This report describes oxide (passive film) formation on Alloy 22 surfaces when aged in air (25-750 C) and in solutions (90-110 C) over times ranging from days to 5 years. Most zero-valent metals (and their alloys) are thermodynamically unstable on the earth's surface and in its upper crust. Most will therefore convert to oxides when exposed to a surficial or underground environment. Despite the presence of thermodynamic driving forces, metals and their alloys may persist over lengthy timescales, even under normal atmospheric oxidizing conditions. One reason for this is that as metal is converted to metal oxide, the oxide forms a film on the surface that limits diffusion of chemical components between the environment and the metal. The formation of surface oxide is integral to understanding corrosion rates and processes for many of the more ''resistant'' metals and alloys. This report describes the correlation between oxide composition and oxide stability for Alloy 22 under a range of relevant repository environments. In the case in which the oxide itself is thermodynamically stable, the growth of the oxide film is a self-limiting process (i.e., as the film thickens, the diffusion across it slows, and the metal oxidizes at an ever-diminishing rate). In the case where the oxide is not thermodynamically stable, it dissolves at the oxide--solution interface as the metal oxidizes at the metal--oxide interface. The system achieves a steady state with a particular oxide thickness when the oxide dissolution and the metal oxidation rates are balanced. Once sufficient metal has transferred to solution, the solution may become saturated with respect to the oxide, which is then thermodynamically stable. The driving force for dissolution at the oxide--solution interface then ceases, and the first case is obtained. In the case of a complex alloy such as Alloy 22 (Haynes International 1997), the development and behavior of the oxide layer is complicated by the fact that different metal components (e.g., Ni, Cr, Mo, W) form distinct oxides, each of which may be stable under somewhat different environmental conditions. For one set of conditions, the oxide layer may be dominated by one or more of these metals, for another, by a different set. Furthermore, the oxide ''layer'' itself may consist of sub-layers of different composition. The purpose of this report is to characterize the oxide layer obtained from Alloy 22 over a range of environmental conditions and to demonstrate that the oxide shows passive behavior. Section 2 provides background information and theoretical predictions describing the role of pH and applied potential in oxide formation and stability. It includes a review of pertinent data on similar alloys. Section 3 presents data characterizing the oxide over a range applied potential and pH. Section 4 evaluates the oxide obtained from Alloy 22 samples aged for time periods extending from one month to over five years. Section 5 presents data showing that the oxide growth rate is logarithmic in time. Section 6 discusses the stability of the oxide as determined by short-term electrochemical tests. Section 7 describes the oxide scale that forms due to thermal processing (solution annealing and in air). Taken together, the various sections in this report present an understanding of the oxide layer obtained using a variety of methodologies, techniques, and testing conditions. An Appendix provides additional information regarding surface analysis techniques and electrochemical testing.

Orme, C A

2005-09-09

331

Relationship between shear elastic modulus and passive muscle force: an ex-vivo study.  

PubMed

As muscle is stretched, it reacts with increasing passive resistance. This passive force component is important for normal muscle function. Unfortunately, direct measurement of passive muscle force is still beyond the current state-of-the-art. This study aimed to investigate the feasibility of using Supersonic shear wave elastography (SSWE) to indirectly measure passive muscle force. Sixteen gastronomies pars externus and 16 tibialis anterior muscles were dissected from 10 fresh roaster chickens. For each muscle specimen, the proximal bone-tendon junction was kept intact with its tibia or femur clamped in a fixture. Calibration weights (0-400 g in 25 g per increment) were applied to the distal tendon via a pulley system and muscle elasticity was measured simultaneously using SSWE. The measurements were repeated for 3 cycles. The elasticity-load relationship of each tested muscle for each loading cycle was analyzed by fitting a least-squares regression line to the data. Test-retest reliability was evaluated using intraclass correlation coefficient (ICC). Results demonstrated that the relationships between SSWE elasticity and passive muscle force were highly linear for all the tested muscles with coefficients of determination ranging between 0.971 and 0.999. ICCs were 0.996 and 0.985, respectively, for the slope and y-intercept parameters of the regression lines, indicating excellent reliability. These findings indicate that SSWE, when carefully applied, can be a highly reliable technique for muscle elasticity measurements. The linear relationship between SSWE elasticity and passive muscle force identified in the present study demonstrated that SSWE may be used as an indirect measure of passive muscle force. PMID:23769175

Koo, Terry K; Guo, Jing-Yi; Cohen, Jeffrey H; Parker, Kevin J

2013-08-01

332

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

333

Passive ventilation for residential air quality control  

SciTech Connect

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

Axley, J.

1999-07-01

334

HTR1B, ADIPOR1, PPARGC1A, and CYP19A1 and Obesity in a Cohort of Caucasians and African Americans: An Evaluation of Gene-Environment Interactions and Candidate Genes  

PubMed Central

The World Health Organization estimates that the number of obese and overweight adults has increased to 1.6 billion, with concomitant increases in comorbidity. While genetic factors for obesity have been extensively studied in Caucasians, fewer studies have investigated genetic determinants of body mass index (BMI; weight (kg)/height (m)2) in African Americans. A total of 38 genes and 1,086 single nucleotide polymorphisms (SNPs) in African Americans (n = 1,173) and 897 SNPs in Caucasians (n = 1,165) were examined in the Southern Community Cohort Study (2002–2009) for associations with BMI and gene × environment interactions. A statistically significant association with BMI survived correction for multiple testing at rs4140535 (? = ?0.04, 95% confidence interval: ?0.06, ?0.02; P = 5.76 × 10?5) in African Americans but not in Caucasians. Gene-environment interactions were observed with cigarette smoking and a SNP in ADIPOR1 in African Americans, as well as between a different SNP in ADIPOR1 and physical activity in Caucasians. A SNP in PPARGC1A interacted with alcohol consumption in African Americans, and a different SNP in PPARGC1A was nominally associated in Caucasians. A SNP in CYP19A1 interacted with dietary energy intake in African Americans, and another SNP in CYP191A had an independent association with BMI in Caucasians.

Edwards, Todd L.; Velez Edwards, Digna R.; Villegas, Raquel; Cohen, Sarah S.; Buchowski, Maciej S.; Fowke, Jay H.; Schlundt, David; Long, Ji Rong; Cai, Qiuyin; Zheng, Wei; Shu, Xiao-Ou; Hargreaves, Margaret K.; Jeffrey, Smith; Williams, Scott M.; Signorello, Lisa B.; Blot, William J.; Matthews, Charles E.

2012-01-01

335

HTR1B, ADIPOR1, PPARGC1A, and CYP19A1 and obesity in a cohort of Caucasians and African Americans: an evaluation of gene-environment interactions and candidate genes.  

PubMed

The World Health Organization estimates that the number of obese and overweight adults has increased to 1.6 billion, with concomitant increases in comorbidity. While genetic factors for obesity have been extensively studied in Caucasians, fewer studies have investigated genetic determinants of body mass index (BMI; weight (kg)/height (m)(2)) in African Americans. A total of 38 genes and 1,086 single nucleotide polymorphisms (SNPs) in African Americans (n = 1,173) and 897 SNPs in Caucasians (n = 1,165) were examined in the Southern Community Cohort Study (2002-2009) for associations with BMI and gene × environment interactions. A statistically significant association with BMI survived correction for multiple testing at rs4140535 (? = -0.04, 95% confidence interval: -0.06, -0.02; P = 5.76 × 10(-5)) in African Americans but not in Caucasians. Gene-environment interactions were observed with cigarette smoking and a SNP in ADIPOR1 in African Americans, as well as between a different SNP in ADIPOR1 and physical activity in Caucasians. A SNP in PPARGC1A interacted with alcohol consumption in African Americans, and a different SNP in PPARGC1A was nominally associated in Caucasians. A SNP in CYP19A1 interacted with dietary energy intake in African Americans, and another SNP in CYP191A had an independent association with BMI in Caucasians. PMID:22106445

Edwards, Todd L; Velez Edwards, Digna R; Villegas, Raquel; Cohen, Sarah S; Buchowski, Maciej S; Fowke, Jay H; Schlundt, David; Long, Jirong; Long, Ji Rong; Cai, Qiuyin; Zheng, Wei; Shu, Xiao-Ou; Hargreaves, Margaret K; Smith, Jeffrey; Jeffrey, Smith; Williams, Scott M; Signorello, Lisa B; Blot, William J; Matthews, Charles E

2012-01-01

336

Breast cancer risk, fungicide exposure and CYP1A1*2A gene-environment interactions in a province-wide case control study in Prince Edward Island, Canada.  

PubMed

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

2012-05-01

337

Fused performance of passive thermal and active polarimetric EO demining sensor  

NASA Astrophysics Data System (ADS)

The potential for performance improvements through sensor fusion is explored for two electro-optical (EO) imaging sensors: a passive thermal IR camera and an active polarimetric system. Tests of decision-level fusion using a small data set (roughly 60 mine signatures) suggest that a significant performance improvement can be obtained by using an AND fusion approach. The source of this improvement derives from correlation among the sensors. Specifically, the sensors exhibit a strong positive correlation when a mine is present, and a negligible correlation when viewing clutter. The observed improvement is independent of the local ground clutter, but it depends strongly on the decision thresholds used for the individual sensors.

Liao, Wen-Jiao; Baertlein, Brian A.

2002-08-01

338

Photoluminescence model of sulfur passivated p-InP nanowires  

NASA Astrophysics Data System (ADS)

The effect of ammonium polysulfide solution, (NH4)2Sx, on the surface passivation of p-doped InP nanowires (NWs) was investigated by micro-photoluminescence. An improvement in photoluminescence (PL) intensity from individual NWs upon passivation was used to optimize the passivation procedure using different solvents, sulfur concentrations and durations of passivation. The optimized passivation procedure gave an average of 24 times improvement in peak PL intensity. A numerical model is presented to explain the PL improvement upon passivation in terms of a reduction in surface trap density by two orders of magnitude from 1012 to 1010 cm-2, corresponding to a change in surface recombination velocity from 106 to 104 cm s-1. The diameter dependence of the PL intensity is investigated and explained by the model. The PL intensity from passivated nanowires decreased to its initial (pre-passivation) value over a period of seven days in ambient air, indicating that the S passivation was unstable.

Tajik, N.; Haapamaki, C. M.; LaPierre, R. R.

2012-08-01

339

Altered Passive Eruption and Familial Trait: A Preliminary Investigation  

PubMed Central

Altered passive eruption is described as a condition in which the relationship between teeth, alveolar bone, and the soft tissues creates an excessive gingival display and, in turn, in some circumstances, it may reveal a clinical aspect also known as the “gummy smile.” The surgical management of such cases is well understood and has been widely described, with mucogingival and osseous resective procedures being predictable surgical means leading to more balanced aesthetics and proper display of the teeth anatomy. The possible familial trait in case of passive eruption and therefore the possibility of recurrence of the same condition in families of siblings or parents of affected patients have been investigated in this study. 20 patients have been selected and treated in both a private practice and university settings and their immediate family trees were evaluated in order to understand the incidence of the condition. 65% of the treated patients had one or more family members with the same condition leading to seeking further investigation on the possible genetic correlation.

Brunelli, Giorgio; Piras, Vincenzo

2014-01-01

340

Hydrogen passivation of deep levels in n-GaN  

NASA Astrophysics Data System (ADS)

Differential postgrowth hydrogen passivation of deep levels in n-GaN grown by metal-organic chemical vapor deposition has been directly observed by means of both deep level transient spectroscopy and deep level optical spectroscopy. Two deep levels found at Ec-Et=0.62 and 1.35 eV show strong H passivation effects, with their concentrations decreasing by a factor of >=30 and ~14, respectively. The decrease in the 0.62 eV trap concentration together with its correlation with the presence of Mg in n-GaN is consistent with Mg-H complex formation. A band of closely spaced deep levels observed at Ec-Et=2.64-2.80 eV narrows to Ec-Et=2.74-2.80 eV after hydrogenation, consistent with hydrogen complexing with VGa3- defects as anticipated by earlier theoretical results. Finally, a deep level at Ec-Et=3.22 eV likely related to background acceptors remains unaffected by hydrogen.

Hierro, A.; Ringel, S. A.; Hansen, M.; Speck, J. S.; Mishra, U. K.; Denbaars, S. P.

2000-09-01

341

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

342

[Advances in passive OP-FTIR].  

PubMed

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

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

2005-10-01

343

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

344

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

345

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.

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

2011-01-01

346

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

347

Passivated emitters in silicon solar cells  

NASA Astrophysics Data System (ADS)

In high-efficiency silicon solar cells with low metal contact coverage fractions and high bulk lifetimes, cell performance is often dominated by recombination in the oxide-passivated diffusions on the cell surface. Measurements of the emitter saturation current density, Jo, of oxide-passivated, boron and phosphorus diffusions are presented, and from these measurements, the dependence of surface recombination velocity on dopant concentration is extracted. The lowest observed values of Jo which are stable under UV light are given for both boron- and phosphorus-doped, oxide-passivated diffusions, for both textured and untextured surfaces. Contour plots which incorporate the above data were applied to two types of backside-contact solar cells with large area (37.5 sq cm) and one-sun efficiencies up to 22.7 percent.

King, Richard R.; Gruenbaum, Peter E.; Sinton, Ronald A.; Swanson, Richard M.

348

Complete corrosion inhibition through graphene defect passivation.  

PubMed

Graphene is expected to enable superior corrosion protection due to its impermeability and chemical inertness. Previous reports, however, demonstrate limited corrosion inhibition and even corrosion enhancement of graphene on metal surfaces. To enable the reliable and complete passivation, the origin of the low inhibition efficiency of graphene was investigated. Combining electrochemical and morphological characterization techniques, nanometer-sized structural defects in chemical vapor deposition grown graphene were found to be the cause for the limited passivation effect. Extremely fast mass transport on the order of meters per second both across and parallel to graphene layers results in an inhibition efficiency of only ?50% for Cu covered with up to three graphene layers. Through selective passivation of the defects by atomic layer deposition (ALD) an enhanced corrosion protection of more than 99% was achieved, which compares favorably with commercial corrosion protection methods. PMID:24359599

Hsieh, Ya-Ping; Hofmann, Mario; Chang, Kai-Wen; Jhu, Jian Gang; Li, Yuan-Yao; Chen, Kuang Yao; Yang, Chang Chung; Chang, Wen-Sheng; Chen, Li-Chyong

2014-01-28

349

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

350

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

351

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

PubMed Central

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

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

2011-01-01

352

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

PubMed

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

Sabra, Karim G; Huston, Steven

2011-05-01

353

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

354

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

355

Passive Polarimetric Information Processing for Target Classification  

NASA Astrophysics Data System (ADS)

Polarimetric sensing is an area of active research in a variety of applications. In particular, the use of polarization diversity has been shown to improve performance in automatic target detection and recognition. Within the diverse scope of polarimetric sensing, the field of passive polarimetric sensing is of particular interest. This chapter presents several new methods for gathering in formation using such passive techniques. One method extracts three-dimensional (3D) information and surface properties using one or more sensors. Another method extracts scene-specific algebraic expressions that remain unchanged under polariza tion transformations (such as along the transmission path to the sensor).

Sadjadi, Firooz; Sadjadi, Farzad

356

Distant synchronization through a passive medium  

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

357

Passive margin earthquakes: Reviewing knowledge and challenges  

NASA Astrophysics Data System (ADS)

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

Balcerak, Ernie

2012-03-01

358

Passive Thoron-Measurements With And Without Pinocchio's Help  

NASA Astrophysics Data System (ADS)

It is common practice to measure radon gas concentration as a surrogate of its decay products by using a known value of the equilibrium factor. Unfortunately a similar approach has been often used to infer the thoron gas concentration from the measurement of 212Pb, in spite of the fact that the concept of an equilibrium factor is no more meaningful. In order to study the profile of thoron and its decay products in the vicinity of the wall, a passive monitor consisting of a 25cm-long diffusion tube has been used. The most difficult problem in practice is to keep this monitor-tube perpendicular to vertical walls. This problem has been solved by using a 25cm-long nose of a Pinocchio mask. The most important characteristic of the long-nose-geometry for thoron measurements is that it makes it possible to estimate the largest indoor concentrations of thoron, which occur at zero distances from the source under stagnant air conditions. When thoron measurements are carried out without the help from Pinocchio, it is important that the monitors lay adjacent to the thoron emanating surface. Different types of compact passive monitors are available which make it possible to measure thoron in the vicinity of the exhaling surfaces. In these cases, a combination of two different passive monitors is used in order to differentiate the thoron from radon. Because of the lack of correlation between thoron gas and its decay product, 212Pb, a correct dose estimate requires the measurement of the concentration of both radionuclides (220Rn and 212Pb) separately. While the thoron gas should be measured in the vicinity of the exhaling surface just the opposite is true for the 212Pb, which should be measured tens of cm away from said surface. Passive measurements of 212Pb are typically carried out by track detectors with suitable degraders of the alpha-particles energy. Once again Pinocchio can be very helpful, since by positioning the 212Pb at the tip of his nose, he can ensure the exposure of the 212Pb detector always at the same distance from said exhalation surface.

Tommasino, L.; Paschoa, A. S.; Tommasino, M. C.

2008-08-01

359

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

360

Passive measurements of mixed-oxide fuel for nuclear nonproliferation  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

361

The Construct Validity of Passive-Aggressive Personality Disorder  

PubMed Central

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

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

2010-01-01

362

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

363

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.

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

2014-01-01

364

Correlative Tomography  

NASA Astrophysics Data System (ADS)

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.

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.

2014-04-01

365

Correlative tomography.  

PubMed

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

366

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.

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

367

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

368

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

369

Tracking marine mammals using passive acoustics  

Microsoft Academic Search

It is difficult to study the behavior and physiology of marine mammals or to understand and mitigate human impact on them because much of their lives are spent underwater. Since sound propagates for long distances in the ocean and since many cetaceans are vocal, passive acoustics is a valuable tool for studying and monitoring their behavior. After a brief introduction

Eva-Marie Nosal

2007-01-01

370

Thermal-hydraulic unreliability of passive systems  

Microsoft Academic Search

Advanced light water reactor (LWR) like AP600 and the simplified boiling water reactor use passive safety systems for accident prevention and mitigation. Because these systems rely on natural forces for their operation, their unavailability due to hardware failures and human error is significantly smaller than that of active systems. However, the coolant flows predicted to be delivered by these systems

C. P. Tzanos; N. T. Saltos

1995-01-01

371

Thermal-hydraulic unreliability of passive systems  

Microsoft Academic Search

Advanced light water reactor designs like AP600 and the simplified boiling water reactor (SBWR) use passive safety systems for accident prevention and mitigation. Because these systems rely on natural forces for their operation, their unavailability due to hardware failures and human error is significantly smaller than that of active systems. However, the coolant flows predicted to be delivered by these

C. P. Tzanos; N. T. Saltos

1995-01-01

372

Passivation of Steel with Aqueous Amine Solutions.  

National Technical Information Service (NTIS)

This is a process that allows previously cleaned steel (which may have been cleaned in any of several different ways) to be passivated with a rinse of almost pure water, that is made slightly alkaline to inhibit corrosion, and flash rusting such that any ...

P. J. Hearst

1985-01-01

373

Passivation of Steel with Aqueous Amine Solution.  

National Technical Information Service (NTIS)

This is a method for passivating steel surfaces to prevent flash rusting by ensuring that the steel surface remains in an alkaline condition, following cleaning, until all water is evaporated. A 5 to 10 percent citric acid solution, for example, adjusted ...

P. J. Hearst

1983-01-01

374

Passive Ranging and Target Motion Analysis.  

National Technical Information Service (NTIS)

A review is made of various methods for passive ranging and target motion analysis, including some new methods based on three tracking legs. Estimators for range and other parameters are compared with respect to their responses to errors from four major s...

J. M. Dobbie

1971-01-01

375

Helical axes of passive knee joint motions  

Microsoft Academic Search

The purpose of this study was to determine finite helical axes for passive knee joint motions in vitro and to evaluate the descriptive value of the finite helical axes for step-by-step Rexion motions, with respect to consistency and reproducibility. An accurate Roentgenstereophotogrammetric system was used for motion measurements. Four knees were tested in a motion and loading rig with one

L. Blankevoort; HWJ Huiskes; A. de Lange

1990-01-01

376

Passive booster for pumping liquified gases  

SciTech Connect

The present invention comprises a method and apparatus for maintaining a liquified gas such as CO/sub 2/ or N/sub 2/ 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 placed in the liquified gas feed line between the gas source and the positive displacement pump. Gas is introduced into the shell side of the passive booster from a chamber in the tube side through a variable orifice throttling valve which, through the Joule-Thomson Effect, drops the temperature of the gas in the shell to provide refrigeration for the main liquified gas flow through the tube side of the passive booster. Flow through the variable orifice valve may be controlled manually or automatically. A back pressure valve on the shell side of the passive booster may be employed to prevent solid formation if one is employing liquified CO/sub 2/, which forms a solid phase at low temperature at normal atmospheric pressure.

Hamid, S.

1984-12-11

377

Computational methods for passive solar simulation  

Microsoft Academic Search

The use of network models and a range of computational methods for the simulation of passive solar buildings are described, compared, and assessed. The following methods are considered: (i) steady-state methods; (ii) finite difference methods, explicit and implicit; (iii) modal or analytic spectral methods; (iv) Fourier series methods. Methods (ii) to (iv) are compared by applying them to a series

C CARTER

1990-01-01

378

Photodetectors with passive thermal radiation control  

DOEpatents

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

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

2001-10-02

379

Active and Passive Smoking in Military Women.  

National Technical Information Service (NTIS)

Despite a recent decline in smoking by military personnel, military members and their dependents continue to smoke at rates that are higher than their civilian counterparts. The purpose of the original study was to test of a model active and passive smoki...

J. Agazio

1997-01-01

380

KARO BATAK: PASSIVE, ERGATIVE OR NEITHER?  

Microsoft Academic Search

This paper focuses on three questions relating to Western Malayo-Polynesian syntactic typology. Two are general questions concerned with relevant syntactic theory; the first questions the formal differences between passive and ergative constructions and some of the difficulties that arise in distinguishing the two types of construction are discussed. Secondly the usefulness or otherwise of answering the first question is examined.

Clodagh Norwood

1996-01-01

381

Passive component analysis in interleaved buck converters  

Microsoft Academic Search

Interleaved converters are an interesting alternative for many applications due to their advantage in terms of dynamic response, output ripple cancellation, EMI reduction, thermal management and optimized design. In this paper, the benefits of interleaving from the point of view of size and losses reduction of the passive components are quantified. An extensive study has been made considering actual components

J. A. Oliver; P. Zumel; O. Garcia; J. A. Cobos; J. Uceda

2004-01-01

382

Design tools for passive solar applications  

SciTech Connect

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

Balcomb, J.D.

1986-04-01

383

Passivation of InP-based HBTs  

NASA Astrophysics Data System (ADS)

The surface effects, the (NH 4) 2S and low-temperature-deposited SiN x passivations of InP-based heterostructure bipolar transistors (HBTs) have been investigated. The surface recombination current of InP-based HBTs is related to the base structures. The (NH 4) 2S treatment for InGaAs and InP removes the natural oxide layer and results in sulfur-bonded surfaces. This can create surface-recombination-free InP-based HBTs. Degradation is found when the HBTs were exposed to air for 10 days. The low-temperature-deposited SiN x passivation of InGaAs/InP HBTs causes a drastic decrease in the base current and a significant increase in the current gain. The improvement in the HBT performance is attributed to the low deposition temperature and the effect of N 2 plasma treatment in the initial deposition process. The SiN x passivation is found to be stable. S/SiN x passivation of InGaAs/InP HBTs results in a decrease in the base current and an increase in the current gain. The annealing process can cause the base current to decrease further and the current gain increase.

Jin, Z.; Uchida, K.; Nozaki, S.; Prost, W.; Tegude, F.-J.

2006-08-01

384

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

385

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

386

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

387

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

388

Visual Suppression During Passive Eye Movement.  

National Technical Information Service (NTIS)

Visual suppression associated with rapid eye movements is compared for active (voluntary) eye movements and for passive eye movements elicited by tapping the eye. To eliminate retinal blur, test flashes were always delivered at a time when the eye was sta...

W. Richards

1968-01-01

389

Hemodynamic Responses to Passive Body Tilts.  

National Technical Information Service (NTIS)

To investigate the relationship between the effects of gravity and hemodynamic response to body tilt in the early steady-state, twelve healthy young adult males were passively tilted from the supine control position to the 15 degree, 30 degree, and 60 deg...

E. U. Chae Y. S. Suh

1993-01-01

390

Cracks and Corrosion in PSG Passivation Glass  

Microsoft Academic Search

Aluminium corrosion and cracks in single-layer and triple-layer phosphosilicate glasses (PSG) were studied. The optimum phosphorus concentration for producing PSG passivation glass was found to be 3 to 5 mol%. The corrosion of the aluminium was found to proceed by two different processes; a simple electrolytic reaction with water induced by high current density and a cathodic reaction due to

Kenji Takahashi; Kazuya Kitajima; Sumio Imaoka

1982-01-01

391

Passive N-Path Filter Realization.  

National Technical Information Service (NTIS)

Through the intermediary of state-variable equations an equivalence is obtained which shows how passive RC circuits incorporating time-variable gyrators can be used to realize N-path filters. The effects of gyrator losses in the realization of time-invari...

N. DeClaris R. Newcomb S. Chang

1971-01-01

392

Passive damping in EDS maglev systems.  

SciTech Connect

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

Rote, D. M.

2002-05-03

393

Passive Safety Features for Small Modular Reactors.  

National Technical Information Service (NTIS)

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 develope...

D. T. Ingersoll E. Sicily

2010-01-01

394

Remote Passive Road Ice Sensor System (RPRISS).  

National Technical Information Service (NTIS)

RPRISS is a passive infrared (IR) imaging system that can detect the presence of even very thin layers of ice on a paved surfaced. The system can also accurately estimate road surface temperature and provide television-like surveillance of traffic in the ...

J. Reed B. Barbour

1997-01-01

395

Complementary resistive switches for passive nanocrossbar memories  

Microsoft Academic Search

On the road towards higher memory density and computer performance, a significant improvement in energy efficiency constitutes the dominant goal in future information technology. Passive crossbar arrays of memristive elements were suggested a decade ago as non-volatile random access memories (RAM) and can also be used for reconfigurable logic circuits. As such they represent an interesting alternative to the conventional

Eike Linn; Roland Rosezin; Carsten Kügeler; Rainer Waser

2010-01-01

396

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

397

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

398

Limitations of Passive Protection of Quantum Information  

Microsoft Academic Search

The ability to protect quantum information from the effect of noise is one of the major goals of quantum information processing. In this article, we study limitations on the asymptotic stability of quantum information stored in passive N-qubit systems. We consider the effect of small imperfections in the implementation of the protecting Hamiltonian in the form of perturbations or weak

Fernando Pastawski; Alastair Kay; Norbert Schuch; Ignacio Cirac

2009-01-01

399

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

400

Sunspot Time Series: Passive and Active Intervals  

NASA Astrophysics Data System (ADS)

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

Zi?ba, S.; Nieckarz, Z.

2014-07-01

401

Submerged passively-safe power plant  

DOEpatents

The invention as presented consists of a submerged passively-safe power station including a pressurized water reactor capable of generating at least 600 MW of electricity, encased in a double hull vessel, and provides fresh water by using the spent thermal energy in a multistage flash desalination process.

Herring, J. Stephen (Idaho Falls, ID)

1993-01-01

402

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

403

UAV Path Planning for Passive Emitter Localization  

Microsoft Academic Search

A path planning algorithm is presented for uninhabited aerial vehicles (UAVs) trying to geolocate an emitter using passive payload sensors. The objective is to generate a sequence of waypoints for each vehicle that minimizes localization uncertainty. The path planning problem is cast as a nonlinear programming problem using an approximation of the Fisher information matrix (FIM) and solved at successive

Kutluyil Dogancay

2012-01-01

404

A low conversion loss passive frequency doubler  

Microsoft Academic Search

We propose a distributed passive frequency doubler using a bandgap nonlinear transmission line (NLTL) that can achieve low conversion loss even for small input power levels. We also develop a theoretical model of second harmonic generation for a homogeneous NLTL and show adverse effects of dispersion. To resolve dispersion, a bandgap NLTL is introduced which can reach the theoretical limit

Muhammad Adnan; Ehsan Afshari

2011-01-01

405

SAW wireless, passive sensor spread spectrum platforms  

Microsoft Academic Search

SAW technology has been identified as a possible solution for NASA's long term needs for ground, space-flight, and space-exploration sensor requirements. SAW has many unique advantages over possible competing technologies, which include the following properties: passive, radiation hard, operable over wide temperature ranges, small, rugged, inexpensive, and identifiable. The purpose of this paper is a focus on the platform and

J. M. Pavlina; B. Santos; N. Kozlovski; D. C. Malocha

2008-01-01

406

CAN CONTINGENT VALUATION MEASURE PASSIVE USE VALUES  

EPA Science Inventory

Contingent valuation (CV) is the only method currently available for practically measuring passive-use values. Because proposed laws may require that environmental regulations pass a benefit-cost test, CV has become central to the policy debate on environmental protection. Crit...

407

Passive visual fingerprinting of network attack tools  

Microsoft Academic Search

This paper examines the dramatic visual fingerprints left by a wide variety of popular network attack tools in order to better understand the specific methodologies used by attackers as well as the identifiable characteristics of the tools themselves. The techniques used are entirely passive in nature and virtually undetectable by the attackers. While much work has been done on active

Gregory J. Conti; Kulsoom Abdullah

2004-01-01

408

What Kind of Continental Margin am I? Active or Passive?  

NSDL National Science Digital Library

Volcanoes, earthquakes, and topography reveal whether a continental margin is active or passive. In this activity, students use the GeoMapApp tool to work with earthquake, volcano, and topographic data to identify active and passive margins.

Wetzel, Laura; Palinkas, Cindy; Bemis, Karen; Mcdaris, John

409

Design Guidelines for a Rule-Based Passive Surveillance System.  

National Technical Information Service (NTIS)

Thesis addresses the application of artificial intelligence to passive surveillance systems that use waveform analysis as their primary means of detecting, classifying and locating a specific target. Discussion is further limited to those passive surveill...

K. E. Jennings

1986-01-01

410

Passive background correction method for spatially resolved detection  

DOEpatents

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

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

2011-05-10

411

Surface passivation process of compound semiconductor material using UV photosulfidation  

DOEpatents

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

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

1995-01-01

412

Land surface temperature derived from the SSM\\/I passive microwave brightness temperatures  

Microsoft Academic Search

Passive microwave brightness temperatures from the Defense Meteorological Space Program Special Sensor Microwave\\/Imager (SSM\\/I) were used to determine surface temperature over land areas in the central plains of the United States. A regression analysis comparing all of the SSM\\/I channels and minimum screen air temperatures (representing the surface temperature) showed good correlations, with root-mean-square errors of 2-3 degC. Pixels containing

M. J. McFarland; R. L. Miller; C. M. U. Neale

1990-01-01

413

Hybrid passivated colloidal quantum dot solids  

NASA Astrophysics Data System (ADS)

Colloidal quantum dot (CQD) films allow large-area solution processing and bandgap tuning through the quantum size effect. However, the high ratio of surface area to volume makes CQD films prone to high trap state densities if surfaces are imperfectly passivated, promoting recombination of charge carriers that is detrimental to device performance. Recent advances have replaced the long insulating ligands that enable colloidal stability following synthesis with shorter organic linkers or halide anions, leading to improved passivation and higher packing densities. Although this substitution has been performed using solid-state ligand exchange, a solution-based approach is preferable because it enables increased control over the balance of charges on the surface of the quantum dot, which is essential for eliminating midgap trap states. Furthermore, the solution-based approach leverages recent progress in metal:chalcogen chemistry in the liquid phase. Here, we quantify the density of midgap trap states in CQD solids and show that the performance of CQD-based photovoltaics is now limited by electron-hole recombination due to these states. Next, using density functional theory and optoelectronic device modelling, we show that to improve this performance it is essential to bind a suitable ligand to each potential trap site on the surface of the quantum dot. We then develop a robust hybrid passivation scheme that involves introducing halide anions during the end stages of the synthesis process, which can passivate trap sites that are inaccessible to much larger organic ligands. An organic crosslinking strategy is then used to form the film. Finally, we use our hybrid passivated CQD solid to fabricate a solar cell with a certified efficiency of 7.0%, which is a record for a CQD photovoltaic device.

Ip, Alexander H.; Thon, Susanna M.; Hoogland, Sjoerd; Voznyy, Oleksandr; Zhitomirsky, David; Debnath, Ratan; Levina, Larissa; Rollny, Lisa R.; Carey, Graham H.; Fischer, Armin; Kemp, Kyle W.; Kramer, Illan J.; Ning, Zhijun; Labelle, André J.; Chou, Kang Wei; Amassian, Aram; Sargent, Edward H.

2012-09-01

414

Hybrid passivated colloidal quantum dot solids.  

PubMed

Colloidal quantum dot (CQD) films allow large-area solution processing and bandgap tuning through the quantum size effect. However, the high ratio of surface area to volume makes CQD films prone to high trap state densities if surfaces are imperfectly passivated, promoting recombination of charge carriers that is detrimental to device performance. Recent advances have replaced the long insulating ligands that enable colloidal stability following synthesis with shorter organic linkers or halide anions, leading to improved passivation and higher packing densities. Although this substitution has been performed using solid-state ligand exchange, a solution-based approach is preferable because it enables increased control over the balance of charges on the surface of the quantum dot, which is essential for eliminating midgap trap states. Furthermore, the solution-based approach leverages recent progress in metal:chalcogen chemistry in the liquid phase. Here, we quantify the density of midgap trap states in CQD solids and show that the performance of CQD-based photovoltaics is now limited by electron-hole recombination due to these states. Next, using density functional theory and optoelectronic device modelling, we show that to improve this performance it is essential to bind a suitable ligand to each potential trap site on the surface of the quantum dot. We then develop a robust hybrid passivation scheme that involves introducing halide anions during the end stages of the synthesis process, which can passivate trap sites that are inaccessible to much larger organic ligands. An organic crosslinking strategy is then used to form the film. Finally, we use our hybrid passivated CQD solid to fabricate a solar cell with a certified efficiency of 7.0%, which is a record for a CQD photovoltaic device. PMID:22842552

Ip, Alexander H; Thon, Susanna M; Hoogland, Sjoerd; Voznyy, Oleksandr; Zhitomirsky, David; Debnath, Ratan; Levina, Larissa; Rollny, Lisa R; Carey, Graham H; Fischer, Armin; Kemp, Kyle W; Kramer, Illan J; Ning, Zhijun; Labelle, André J; Chou, Kang Wei; Amassian, Aram; Sargent, Edward H

2012-09-01

415

Design of high-speed digital correlator in fully polarimetric microwave radiometer  

Microsoft Academic Search

Fully polarimetric microwave radiometer is a new type of passive microwave sensor for measuring ocean wind vector. Digital correlation technology is used in it to get all the four Stokes parameters of ocean emission in this paper. Digital correlator is the main part of fully polarimetric radiometer. In the paper, design of a novel digital correlator is presented. Two high-speed,

Lu Hao; Wang Zhen-Zhan; Liu Jing-Yi; Jiang Jing-Shan

2010-01-01

416

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

417

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

418

Tectonics and Evolution of the Conjugate Passive Margins of the Eastern Gulf of Aden (Encens-Sheba cruise)  

Microsoft Academic Search

The gulf of Aden is one of the few oceanic basins in the world where the two conjugate passive margins are preserved beneath a thin post-rift sedimentary cover and can be correlated within a lateral error smaller than 10 km. It is also one of the few basins where the structures can be followed from the oceanic ridge to the

E. D'Acremont; S. Leroy; P. Ruellan; N. Bellahsen; M. Beslier; M. Fournier; P. Gente; P. Patriat

2001-01-01

419

Minimum-norm with an application to estimation of bearing angles in passive underwater multi-target scenario  

Microsoft Academic Search

Eigen decomposition methods like minimum-norm, MUSIC are used either for frequency estimation of signals or for finding the bearing angles of the sources. In passive underwater multitarget scenario, the requirement is to find both the targets frequency and location simultaneously. Minimum-norm along with minimum data length (MDL) is used for this purpose. The correlation matrix is constructed and the eigen

S. K. Rao; D. A. Sravanthi; K. L. Madhuri

2005-01-01

420

Passive Biomonitoring with Lichens as a Part of an Integrated Biological Measuring System for Monitoring Air Pollution in Switzerland  

Microsoft Academic Search

Passive Biomonitoring with the folious lichen Hypogymnia physodes (L.) Nyl. has been tested in Switzerland. Multielement analyses enable qualitative and quantitative conclusions about the composition and amount of important active pollutants. Many elements correlate well with the general air pollution indicator IAP18. Hypogymnia physodes possess good accumulation capacity for important air pollutants. The method has been calibrated for Pb and

R. Herzig; L. Liebendörfer; M. Urech; K. Ammann; M. Cuecheva; W. Landolt

1989-01-01

421

The Passive in 3- and 4-Year-Olds  

ERIC Educational Resources Information Center

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

de Barros Pereira Rubin, Maraci Coelho

2009-01-01

422

A local geopotential model for implementation of underwater passive navigation  

Microsoft Academic Search

A main aspect of underwater passive navigation is how to identify the vehicle location on an existing gravity map, and several matching algorithms as ICCP and SITAN are the most prevalent methods that many scholars are using. In this paper, a novel algorithm that is different from matching algorithms for passive navigation is developed. The algorithm implements underwater passive navigation

Zhigang Wang; Shaofeng Bian

2008-01-01

423

Passivation of cracking catalysts with cadmium and tin  

Microsoft Academic Search

A method for passivating the adverse catalytic effects of metal contaminants, such as nickel, vanadium and iron, which become deposited on cracking catalyst is disclosed. A passivation promoter comprising elemental tin and\\/or a tin compound in combination with elemental cadmium and\\/or a cadmium compound is deposited on the catalyst and the catalyst is passed through a passivation zone having a

Bertch

1985-01-01

424

Active versus passive damping in large flexible structures  

NASA Technical Reports Server (NTRS)

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

Slater, Gary L.; Mclaren, Mark D.

1991-01-01

425

Cross-sectional transmission electron microscopy\\/electron beam induced current investigations on as-grown and hydrogen-passivated, gas-assisted solidified polycrystalline silicon  

Microsoft Academic Search

Gas-assisted-solidified (GAS) polycrystalline silicon was developed for low-cost solar cells. The as-grown and hydrogen-passivated samples were investigated by the electron beam induced current (EBIC) technique and cross-sectional transmission electron microscopy (XTEM). The shallow penetrated EBIC line profiles across the grain boundaries were used to monitor the effects of hydrogen passivation, and the results were correlated with those revealed by the

C. H. Chu; C. Y. Sun; H. L. Hwang

1989-01-01

426

PHACT: Parallel HOG and Correlation Tracking  

NASA Astrophysics Data System (ADS)

Histogram of Oriented Gradients (HOG) based methods for the detection of humans have become one of the most reliable methods of detecting pedestrians with a single passive imaging camera. However, they are not 100 percent reliable. This paper presents an improved tracker for the monitoring of pedestrians within images. The Parallel HOG and Correlation Tracking (PHACT) algorithm utilises self learning to overcome the drifting problem. A detection algorithm that utilises HOG features runs in parallel to an adaptive and stateful correlator. The combination of both acting in a cascade provides a much more robust tracker than the two components separately could produce.

Hassan, Waqas; Birch, Philip; Young, Rupert; Chatwin, Chris

2014-03-01

427

Analysis and suppression of passive noise in surface microseismic data  

NASA Astrophysics Data System (ADS)

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

Forghani-Arani, Farnoush

428

Electrochemical emission and impedance spectroscopies of passive iron and carbon steel  

NASA Astrophysics Data System (ADS)

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

Liu, Jun

429

Correlation spectrometer  

DOEpatents

A correlation spectrometer can detect a large number of gaseous compounds, or chemical species, with a species-specific mask wheel. In this mode, the spectrometer is optimized for the direct measurement of individual target compounds. Additionally, the spectrometer can measure the transmission spectrum from a given sample of gas. In this mode, infrared light is passed through a gas sample and the infrared transmission signature of the gasses present is recorded and measured using Hadamard encoding techniques. The spectrometer can detect the transmission or emission spectra in any system where multiple species are present in a generally known volume.

Sinclair, Michael B. (Albuquerque, NM) [Albuquerque, NM; Pfeifer, Kent B. (Los Lunas, NM) [Los Lunas, NM; Flemming, Jeb H. (Albuquerque, NM) [Albuquerque, NM; Jones, Gary D. (Tijeras, NM) [Tijeras, NM; Tigges, Chris P. (Albuquerque, NM) [Albuquerque, NM

2010-04-13

430

Phosphorous passivation of the SiO 2/4H-SiC interface  

NASA Astrophysics Data System (ADS)

We describe experimental and theoretical studies to determine the effects of phosphorous as a passivating agent for the SiO 2/4H-SiC interface. Annealing in a P 2O 5 ambient converts the SiO 2 layer to PSG (phosphosilicate glass) which is known to be a polar material. Higher mobility (approximately twice the value of 30-40 cm 2/V s obtained using nitrogen introduced with an anneal in nitric oxide) and lower threshold voltage are compatible with a lower interface defect density. Trap density, current-voltage and bias-temperature stress (BTS) measurements for MOS capacitors are also discussed. The BTS measurements point to the possibility of an unstable MOSFET threshold voltage caused by PSG polarization charge at the O-S interface. Theoretical considerations suggest that threefold carbon atoms at the interface can be passivated by phosphorous which leads to a lower interface trap density and a higher effective mobility for electrons in the channel. The roles of phosphorous in the passivation of correlated carbon dangling bonds, for SiC counter-doping, for interface band-tail state suppression, for Na-like impurity band formation and for substrate trap passivation are also discussed briefly.

Sharma, Y. K.; Ahyi, A. C.; Issacs-Smith, T.; Shen, X.; Pantelides, S. T.; Zhu, X.; Feldman, L. C.; Rozen, J.; Williams, J. R.

2012-02-01

431

Use of passive alpha detectors to screen for uranium contamination in a field at Fernald, Ohio  

SciTech Connect

This paper reports the results from a field test of newly developed techniques for inexpensive, in situ screening of soil for alpha contamination. Passive alpha detectors that are commercially available for the detection indoor airborne alpha activity (i.e., {sup 222}Rn) have been modified so they can be applied to the detection of alpha contamination on surfaces or in soils. Results reported here are from an intercomparison involving several different techniques with all measurements being made at the same sites in a field near the formerly used uranium processing facility at Fernald, Ohio, during the summer of 1994. The results for two types of passive alpha detector show that the quality of calibration is improved if soils samples are milled to increase homogeneity within the soil matrices. The correlation between laboratory based radiochemical analyses and quick, field-based screening measurements is acceptable and can be improved if the passive devices are left for longer exposure times in the field. The total cost per measurement for either type of passive alpha detector is probably less than $25 and should provide a cost-effective means for site managers to develop the information needed to find areas with remaining alpha contamination so resources can be allocated efficiently.

Dudney, C.S.; Meyer, K.E.; Gammage, R.B. [Oak Ridge National Lab., TN (United States); Wheeler, R.V.; Salasky, M. [Landauer, Inc., Glenwood, IL (United States); Kotrappa, P. [Rad Electric Inc., Frederick, MD (United States)

1995-06-01

432

Managing passive incontinence and incomplete evacuation.  

PubMed

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

Collins, Brigitte; Norton, Christine

433

Passive solar heating and cooling means  

SciTech Connect

The invention comprises means of controlling the insolation and radiation of passive solar thermal storage columns for heating and cooling of homes and other structures. In one embodiment rotatable insulating panels control the exposure of round thermal storage columns to daytime sunlight and the nighttime sky. A second embodiment allows independent rotation of the column and the insulation panel for further control of the insolation and radiation. In a third embodiment the rotatable insulating panels are positioned in concave depressions formed in vertical thermal storage columns. These columns include individual thermal convection means formed therein and are particularly suited to precast concrete or masonry construction. In a fourth embodiment the rotatable panels are adapted to retrofit existing masonry walls for passive solar thermal storage. The constructions disclosed can be utilized for vertical walls, sloping walls and roofs and flat roofs. Structural support must be modified depending on the orientation, however, the basic modes of operation are suitable for all orientations.

Lee, K.S.

1984-01-10

434

Wavelength sharing in WDM passive optical networks  

NASA Astrophysics Data System (ADS)

Progress towards the definition of next-generation passive optical networks (PONs) based on wavelength-division multiplexing (WDM) is reviewed and compared to emerging requirements. A key challenge is providing ultra-high (e.g. 10 Gbps) bandwidth for demanding users while cost-effectively supporting less-demanding users. A new approach is presented in which diverse bandwidth requirements are supported on a conventional WDM PON outside plant through the use of flexible wavelength sharing in the local office. An example is demonstrated experimentally showing that with 16 users per passive node, each wavelength can be shared by up to 16 users distributed across up to 16 PONs served by the same local office. Factors limiting sharing and throughput are discussed.

Darcie, Thomas E.; Barakat, Neil; Iannone, Patrick P.; Reichmann, Kenneth C.

2008-11-01

435

Passive control of wing/store flutter  

NASA Technical Reports Server (NTRS)

Results are presented for a passive flutter suppression approach known as the decoupler pylon. The decoupler pylon dynamically isolates the wing from store pitch inertia effects by means of soft spring/damper elements assisted by a low frequency feedback control system which minimizes static pitch deflections of the store because of maneuvers and changing flight conditions. Wind tunnel tests and analyses show that this relatively simple pylon suspension system provides substantial increases in flutter speed and reduces the sensitivity of flutter to changes in store inertia and center of gravity. Flutter characteristics of F-16 and YF-17 flutter models equipped with decoupler pylon mounted stores are presented and compared with results obtained on the same model configuration with active flutter suppression systems. These studies show both passive and active concepts to be effective in suppressing wing/store flutter. Also presented are data showing the influence of pylon stiffness nonlinearities on wing/store flutter.

Reed, W. H., III; Cazier, F. W., Jr.; Foughner, J. T., Jr.

1980-01-01

436

Passive infrared ice detection for helicopter applications  

NASA Technical Reports Server (NTRS)

A technique is proposed to remotely detect rotor icing on helicopters by using passive IR thermometry to detect the warming caused by latent heat release as supercooled water freezes. During icing, the ice accretion region will be warmer than the uniced trailing edge, resulting in a characteristic chordwise temperature profile. Preliminary tests were conducted on a static model in the NASA Icing Research Tunnel for a variety of wet (glaze) and dry (rime) ice conditions. The chordwise temperature profiles were confirmed by observation with an IR thermal video system and thermocouple observations. The IR observations were consistent with predictions of the LEWICE ice accretion code, which was used to extrapolate the observations to rotor icing conditions. Based on the static observations, the passive IR ice detection technique appears promising; however, further testing or rotating blades is required.

Dershowitz, Adam L.; Hansman, R. John, Jr.

1990-01-01

437

Linear and passive silicon optical isolator  

PubMed Central

On-chip optical isolation plays a key role in optical communications and computing based on silicon integrated photonic structures and has attracted great attentions for long years. Recently there have appeared hot controversies upon whether isolation of light can be realized via linear and passive photonic structures. Here we demonstrate optical isolation of infrared light in purely linear and passive silicon photonic structures. Both numerical simulations and experimental measurements show that the round-trip transmissivity of in-plane infrared light across a silicon photonic crystal slab heterojunction diode could be two orders of magnitudes smaller than the forward transmissivity at around 1,550?nm with a bandwidth of about 50?nm, indicating good performance of optical isolation. The occurrence of in-plane light isolation is attributed to the information dissipation due to off-plane and side-way scattering and selective modal conversion in the multiple-channel structure and has no conflict with the reciprocal principle.

Wang, Chen; Zhong, Xiao-Lan; Li, Zhi-Yuan

2012-01-01

438

Structural Damage Detection Using Virtual Passive Controllers  

NASA Technical Reports Server (NTRS)

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

Lew, Jiann-Shiun; Juang, Jer-Nan

2001-01-01

439

Modeling the formation of passive films on metal surfaces  

NASA Astrophysics Data System (ADS)

Anodic passivation is a critically important phenomenon in lithium ion battery systems. The formation of the SEI (Solid Electrolyte Interphase) layer on the anode during the first few cycles of charging and discharging has a profound effect on battery performance. Formation of the passive layer protects the anode from unwanted side reactions with the electrolyte. However, incomplete or uncontrolled passivation leads to excessive consumption of lithium and this reduces specific capacity. Mathematical models are developed to study the formation of passive films on metal surfaces. The Point defect model is developed to study the formation of passive films on metal surfaces. Vacancy diffusion and migration are considered to be key parameters in studying passive film growth. The variation of the electric field strength is studied across passive film layer. The Point defect Model is compared with the High field model and the results are applied to different metal systems. The formation of anodic passive films on iron metal is studied. Modeling results are compared with experimental data from literature. Though we have studied metal passivation thus far, the applicability of the model lies in the model being able to simulate passive film growth on carbon anodes for lithium ion battery systems. Future battery model studying capacity fading for lithium ion battery systems will be able to use this model to study the impact of passive film on battery behavior.

Krishnamurthy, Balaji

440

Tierra Nueva -- A passive solar cohousing project  

SciTech Connect

California architects take on the formidable challenges of designing a cohousing project, and discover that the end result is well worth the effort. The Tierra Nueva Cohousing Project consists of living units, a common house, community orchard, community gardens, community play space, space for a future shop and at the periphery of the site, parking, carports and garages. The units use thermal mass, solar heating, passive solar cooling, perimeter insulation on slabs. Design was agreed to by the community as a whole.

Haggard, K.; Cooper, P.

1999-10-01