Littérature scientifique sur le sujet « Correlated Exposure »
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Articles de revues sur le sujet "Correlated Exposure"
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Schneider, Peter A., John R. Laird, Gheorghe Doros, Qi Gao, Gary Ansel, Marianne Brodmann, Antonio Micari, Mehdi H. Shishehbor, Gunnar Tepe et Thomas Zeller. « Mortality Not Correlated With Paclitaxel Exposure ». Journal of the American College of Cardiology 73, no 20 (mai 2019) : 2550–63. http://dx.doi.org/10.1016/j.jacc.2019.01.013.
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MacLehose, Richard F., David B. Dunson, Amy H. Herring et Jane A. Hoppin. « Bayesian Methods for Highly Correlated Exposure Data ». Epidemiology 18, no 2 (mars 2007) : 199–207. http://dx.doi.org/10.1097/01.ede.0000256320.30737.c0.
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Gallo, Maria F., Lee Warner, Caroline C. King, Jack D. Sobel, Robert S. Klein, Susan Cu-Uvin, Anne M. Rompalo et Denise J. Jamieson. « Association between Semen Exposure and Incident Bacterial Vaginosis ». Infectious Diseases in Obstetrics and Gynecology 2011 (2011) : 1–10. http://dx.doi.org/10.1155/2011/842652.
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Objective. To identify correlates of incident bacterial vaginosis (BV) diagnosed with Nugent scoring among high-risk women.Study Design. We conducted both cohort and case-crossover analyses, stratified by HIV infection status, based on 871 HIV-infected and 439 HIV-uninfected participants in the HIV Epidemiology Research Study, conducted in 4 US sites in 1993–2000.Results. BV incidence was 21% and 19% among HIV-infected and -uninfected women, respectively. Fewer correlates of BV were found with case-crossover than with cohort design. Reporting frequent coitus (regardless of consistency of condom use) was correlated with BV in cohort analyses but not in case-crossover analyses. The sole correlate of BV in both types of analyses was the detection of spermatozoa on Gram stain, which is a marker of semen exposure.Conclusion. The inconsistent association between condom use and BV in prior studies could be from reporting bias. We found evidence of a relationship between semen exposure and incident BV.
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Siroux, Valérie, Lydiane Agier et Rémy Slama. « The exposome concept : a challenge and a potential driver for environmental health research ». European Respiratory Review 25, no 140 (31 mai 2016) : 124–29. http://dx.doi.org/10.1183/16000617.0034-2016.
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The exposome concept was defined in 2005 as encompassing all environmental exposures from conception onwards, as a new strategy to evidence environmental disease risk factors. Although very appealing, the exposome concept is challenging in many respects. In terms of assessment, several hundreds of time-varying exposures need to be considered, but increasing the number of exposures assessed should not be done at the cost of increased exposure misclassification. Accurately assessing the exposome currently requires numerous measurements, which rely on different technologies; resulting in an expensive set of protocols. In the future, high-throughput ‘omics technologies may be a promising technique to integrate a wide range of exposures from a small numbers of biological matrices. Assessing the association between many exposures and health raises statistical challenges. Due to the correlation structure of the exposome, existing statistical methods cannot fully and efficiently untangle the exposures truly affecting the health outcome from correlated exposures. Other statistical challenges relate to accounting for exposure misclassification or identifying synergistic effects between exposures. On-going exposome projects are trying to overcome technical and statistical challenges. From a public health perspective, a better understanding of the environmental risk factors should open the way to improved prevention strategies.
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Voisin, Dexter R., Dong Ha Kim, Lynn Michalopoulos et Sadiq Patel. « Exposure to Community Violence Among Low-Income African American Youth in Chicago : A Latent Class Analysis ». Violence and Victims 32, no 6 (2017) : 1116–32. http://dx.doi.org/10.1891/0886-6708.vv-d-16-00034.
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African American youth are exposed to some of the highest rates of exposure to community violence. However, few studies have explored factors related to exposures and various subtypes of exposures to community violence (i.e., no exposure, witnessing only and being a witness/victim). Among a matched sample of 129 African American youth and their caregivers, no exposure to community violence was correlated with being heterosexual versus being a lesbian, gay, bisexual, and transgender (LGBT) person, having parents who owned their homes versus rented, and having higher authoritarian parenting attitudes. In addition, being a witness/victim of community violence was correlated with any youth substance use, lower levels of school bonding, having less future orientation, less parental home ownership, and an adverse family history. Practice and programmatic considerations are discussed based on these findings.
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Mandel, Jack S. « Renal cell cancer correlated with occupational exposure to trichloroethylene ». Journal of Cancer Research and Clinical Oncology 127, no 4 (19 mars 2001) : 265–66. http://dx.doi.org/10.1007/s004320000231.
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Vamvakas, S., T. Brüning, H. M. Bolt, D. Henschler et K. Ulm. « Renal cell cancer correlated with occupational exposure to trichloroethene ». Journal of Cancer Research and Clinical Oncology 126, no 3 (18 février 2000) : 178–80. http://dx.doi.org/10.1007/s004320050029.
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Vamvakas, S., T. Brüning, B. Thomasson, M. Lammert, A. Baumüller, H. M. Bolt, W. Dekant, G. Birner, D. Henschler et K. Ulm. « Renal cell cancer correlated with occupational exposure to trichloroethene ». Journal of Cancer Research and Clinical Oncology 124, no 7 (27 juillet 1998) : 374–82. http://dx.doi.org/10.1007/s004320050186.
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Muoka, Alexander K., George O. Agogo, Oscar O. Ngesa et Henry G. Mwambi. « A Method to adjust for measurement error in multiple exposure variables measured with correlated errors in the absence of an internal validation study ». F1000Research 9 (18 décembre 2020) : 1486. http://dx.doi.org/10.12688/f1000research.27892.1.
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Difficulty in obtaining the correct measurement for an individual’s longterm exposure is a major challenge in epidemiological studies that investigate the association between exposures and health outcomes. Measurement error in an exposure biases the association between the exposure and a disease outcome. Usually, an internal validation study is required to adjust for exposure measurement error; it is challenging if such a study is not available. We propose a general method for adjusting for measurement error where multiple exposures are measured with correlated errors (a multivariate method) and illustrate the method using real data. We compare the results from the multivariate method with those obtained using a method that ignores measurement error (the naive method) and a method that ignores correlations between the errors and true exposures (the univariate method). It is found that ignoring measurement error leads to bias and underestimates the standard error. A sensitivity analysis shows that the magnitude of adjustment in the multivariate method is sensitive to the magnitude of measurement error, sign, and the correlation between the errors. We conclude that the multivariate method can be used to adjust for bias in the outcome-exposure association in a case where multiple exposures are measured with correlated errors in the absence of an internal validation study. The method is also useful in conducting a sensitivity analysis on the magnitude of measurement error and the sign of the error correlation.
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Berg, Carla J., Xuejing Duan, Betelihem Getachew, Kim Pulvers, Natalie D. Crawford, Steve Sussman, Yan Ma, Carla Jones-Harrell et Lisa Henriksen. « Young Adult E-cigarette Use and Retail Exposure in 6 US Metropolitan Areas ». Tobacco Regulatory Science 7, no 1 (1 janvier 2021) : 59–75. http://dx.doi.org/10.18001/trs.7.1.5.
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Objectives: Given the need to understand e-cigarette retail and its impact, we examined so- ciodemographic, tobacco and marijuana use, and e-cigarette retail experiences as correlates of (1) past 30-day e-cigarette use, (2) past 30-day advertising/media exposure, and (3) point-of-sale age verification among young adults. Methods: We analyzed baseline survey data (September- December, 2018) among 3006 young adults (ages 18-34) in 6 metropolitan areas (Atlanta, Boston, Minneapolis, Oklahoma City, San Diego, Seattle) in a 2-year longitudinal study. Results: In this sample (Mage = 24.6, 42.3% male, 71.6% white, 11.4% Hispanic), 37.7% (N = 1133) were past 30-day e-cigarette users; 68.6% (N = 2062; non-users: 66.0%, users: 72.9%) reported past 30-day e-cigarette-related advertising/media exposure. Among e-cigarette users, vape shops were the most common source of e-cigarettes (44.7%) followed by online (18.2%). Among users, 34.2% were "almost always" asked for age verification. In multilevel logistic regression, e-cigarette use and advertising/media exposure were correlated (and both correlated with being younger). E- cigarette use also correlated with other tobacco product and marijuana use (and being male and white). Infrequent age verification correlated with commonly purchasing e-cigarettes online (and being older and black). Conclusions: Increased efforts are needed to reduce young adult advertising/media exposure and increase retailer compliance among retailers, particularly online and vape shops.
Thèses sur le sujet "Correlated Exposure"
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Ou, Ju-Chi. « Propensity Score Analysis of Exposure Effects for Spatially Correlated Data ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1263921742.
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Genre, Solene. « To what extent is social media exposure correlated with financial performance for early stage digital consumer-facing startups ? » Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90244.
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Thesis: S.M. in Management Studies, Massachusetts Institute of Technology, Sloan School of Management, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (page 62).
It is very hard to identify and evaluate very early stage investment opportunities in disruptive digital consumer-facing startups as they usually don't have any meaningful revenue data yet. However, these growing startups have "momentums". In classical mechanics, momentum is the product between mass and velocity. When it comes to startups, we can see revenue and web traffic as the mass and unique page views, social presence and sentiment, page rank, inbound links... as velocity (cf. Danielle Morrill start ups momentum index). Analyzing all these data is usually the most relevant way for investors to evaluate investment opportunities. It is however very unclear to what extent startups momentum is an indicator of financial performance. I would like to focus on social media exposure as an indicator of velocity for startups, and investigate further the correlations between social media exposure and revenue data.
by Solene Genre.
S.M. in Management Studies
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PESENTI, NICOLA. « STATISTICAL METHODS FOR CORRELATED PREDICTORS IN PUBLIC HEALTH, WITH APPLICATIONS IN ENVIRONMENTAL AND CLINICAL EPIDEMIOLOGY ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/365518.
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La ricerca epidemiologica mira a generare una migliore comprensione dei meccanismi sanitari e dell'eziologia della malattia. L'abbondanza di informazioni raccolte tramite cartelle cliniche elettroniche ha generato un problema di Big Data, rendendo l'identificazione di modelli predittivi dei rischi per la salute e dei possibili outcome climici ancora più complessa. Pertanto, sono aumentati in importanza e popolarità gli approcci statistici di selezione delle variabili. Tuttavia, i metodi di selezione delle variabili ancora oggi più utilizzati in epidemiologia si basano su conoscenze pregresse o utilizzano approcci automatizzati (es. regressione Stepwise). Quando però si combinano contemporaneamente più variabili d’esposizione con una complessa struttura di correlazione e con potenziali relazioni di tipo non lineare e non additive con l’outcome studiato, questi approcci risultano limitati nel tenere conto della multicollinearità. In questo contesto vengono utilizzati metodi di regressione penalizzati, come il least absolute shrinkage and selection operator (LASSO) e le sue numerose varianti, ma ricerche recenti hanno evidenziato che funzionano male quando sussiste un qualche tipo di struttura complessa di dipendenza tra le covariate. Negli ultimi anni, sono stati sviluppati metodi di selezione delle variabili appartenenti al framework Bayesiano, capaci di gestire congiuntamente più predittori, anche altamente correlati tra loro e con legami non lineari e non additivi con l’outcome. Tra questi metodi Bayesiani spiccano quelli che utilizzano priori spike-and-slab o priori shrinkage. Questi metodi sono ora ampiamente studiati e impiegati all'interno della letteratura epidemiologica ambientale e clinica.
In questo lavoro abbiamo considerato e confrontato tre modelli di selezione delle variabili di tipo Bayesiano: il Bayesian kernel machine regression (BKMR), il Bayesian semiparametric regression (BSR) e il Bayesian LASSO (BLASSO). Il BKMR modellizza le associazioni tra predittori e outcome attraverso l'uso di una funzione kernel dei predittori, il BSR utilizzando spline naturali, mentre il BLASSO attraverso una funzione lineare dei predittori, considerando un parametro di shrinkage che mira ad effettuare selezione delle variabili ponendo a zero il coefficiente di regressione.
In primo luogo, abbiamo valutato la bontà di adattamento e la capacità di selezione dei modelli attraverso uno studio di simulazione, generando diversi scenari con complessa struttura di correlazione e con relazioni disparate tra predittori e outcome. Successivamente, sulla base dei risultati ottenuti nelle simulazioni, abbiamo applicato questi metodi a due casi di studio reali. Il primo è lo studio ROCAV (Rischio di malattie cardiovascolari e aneurisma dell'aorta addominale a Varese), in collaborazione con l'Università dell'Insubria di Varese, con l'obiettivo di studiare l'impatto dell'esposizione a lungo termine a inquinanti ambientali con funzione respiratoria valutata mediante spirometria. I risultati hanno mostrato come non ci sia un inquinante che predomini sugli altri in termini di effetto, ma che tutti contribuiscono all’impatto sulla funzionalità respiratoria.
Nel secondo studio (Follow Up OBese patients at AUXOlogico institute (FUOBAUXO)), in collaborazione con l'Istituto Auxologico Italiano, abbiamo studiato la relazione tra variabili antropometriche, cliniche, biochimiche, infiammatorie e metaboliche sulla perdita di peso percentuale in pazienti affetti da obesità in un periodo di ospedalizzazione di 40 giorni. Il risultato di questo lavoro ha portato all'individuazione di subsets di variabili potenzialmente associate con l’outcome di perdita di peso per diverse tipologie di paziente in base all’età, il genere e livello di BMI.Epidemiological research aims to generate a better understanding of the health mechanisms and disease etiology. Nowadays, the abundance of clinical information collected via electronic medical records have made high-dimensional data extremely popular and the identification of predictive modeling of health risks and possible outcomes has become even more challenging. Therefore, many variable selection approaches have increased in importance and popularity. Nevertheless, the most frequently variable selection methods still used in epidemiology are based on prior knowledge or using stepwise automated selection approaches. However, when multiple exposures co-occur and have a strong complex correlation structure, traditional statistical approaches are limited in accounting for multi-collinearity or standard error inflation. To reduce this problem, dimensionality reduction methods –such as principal component and factor analyses– are very valuable. However, those approaches focus on the transformation of the original variables thus leading to an interpretability issue. In addition, multiple co-occurring predictors can have non-linear and non-additive relationships with the health outcome and most of the statistical methods fail to model properly those relationships. Penalized regression methods are used in this context, such as least absolute shrinkage and selection operator (LASSO) and its numerous variants, but recent research highlighted that they perform poorly when there exists some type of dependence structure between the covariates. In recent years, Bayesian variable selection methods have been developed to handle jointly multiple correlated predictors and both non-linear and non-additive relationships, allowing the inclusion of prior information. Among these Bayesian methods stand out those employing spike-and-slab priors or shrinkage priors for features selection. These methods are now widely studied and employed within the environmental and clinical epidemiological literature. In this thesis work, we considered and compared three Bayesian variable selection models: the Bayesian kernel machine regression (BKMR), the Bayesian semiparametric regression (BSR) and the Bayesian LASSO (BLASSO). BKMR models the outcome-predictors associations using a kernel function of predictors, BSR employing natural splines, while BLASSO using a linear function of predictors and considering a shrinkage parameter that aims to perform variable selection by setting the regression coefficient to zero. We firstly evaluated the models’ goodness of fit and selection ability simulating several predictors with a complex correlation structure and with disparate relationships with a continuous outcome, considering data with different sample sizes. Subsequently, based on the results obtained in the simulations we applied this methods to two real case studies. The first is the ROCAV study (Risk Of Cardiovascular diseases and abdominal aortic Aneurism in Varese), in collaboration with the University of Insubria of Varese, with the aim of studying the impact of long-term exposure to environmental pollutants with respiratory function assessed by spirometry. Results showed that no pollutant overcome the others in terms of effect, but rather all may contribute to the relationship with the respiratory outcome. The second, in collaboration with the Italian Auxological Institute, leveraged data on weight loss in hospitalized obesity affected women from the Follow Up OBese patients at AUXOlogico institute (FUOBAUXO) cohort, with the aim to select most important predictors in explaining the association between biochemical, anthropometric and clinical variables on weight loss percentage in these patients over a period of 40 days. The result of this work led to the identification of subsets of variables potentially associated with the weight loss outcome for different types of patients based on age, gender and BMI level.
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Seabert, Timothy A. « Dietary Markers and Contaminant Exposures Are Correlated to Wild Food Consumption in Two Northern Ontario First Nations Communities ». Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/22829.
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First Nations peoples experience many benefits from eating locally-harvested wild foods, but these benefits must be considered along with the potential risks associated with exposure to environmental contaminants. Unlike store-bought foods, wild foods are an important traditional resource and a significant source of dietary protein, essential minerals and polyunsaturated fatty acids, believed to help in the prevention and treatment of obesity and obesity-related diseases such as type-2 diabetes mellitus. Wild foods continue to be an important and healthy food choice for First Nations peoples; however, they are also a primary source of dietary mercury, polychlorinated biphenyls (PCBs) and other persistent organic pollutants (POPs). To assess the effects of wild food consumption on dietary markers and contaminant accumulation, we grouped individuals from two remote Oji-Cree First Nations communities of north-western Ontario (n=71) according to their level of wild food consumption. In this study, I observed significantly higher organic contaminants in blood and higher mercury concentrations in hair for individuals consuming greater amounts of wild food. Age-adjusted contaminant concentrations were on average 3.5-times higher among high-frequency wild food consumers, with many exceeding federal and international health guidelines for mercury and PCB exposures. Contaminants in these populations approach, and in some cases exceed, threshold levels for adverse effects with potential consequences especially for prenatal development. Here, I also investigated the potential for stable isotope ratios of carbon and nitrogen (δ13C and δ15N) to serve as dietary markers and found strong positive correlations between stable isotopes and frequency of wild food and fish consumption. Frequency of fish consumption and δ15N was also shown to be positively correlated with mercury concentrations in hair and PCB concentrations in plasma. The results of this thesis demonstrate that known differences in dietary behaviour are clearly reflected in stable isotope ratios and contaminant concentrations. The data also show that contaminant exposures to those consuming wild foods in remote Boreal ecosystems is comparable to those associated with serious health effects in industrialized areas, and the problem of contaminants in wild foods is more widespread than the available literature would have led us to believe. These results affect our appreciation of contaminant exposures to First Nations peoples and will have implications for dietary choices, particularly if individuals are encouraged to consume greater amounts of wild foods for their proposed health benefits. We recommend further attention be given to the risks of contaminants in locally-harvested wild foods when promoting the benefits of their consumption to First Nations people as the problem of contaminants in remote communities practicing traditional lifestyles is often underreported and underplayed.
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Harris, Courtenay. « Musculoskeletal outcomes in children using computers : a model representing the relationships between user correlates, computer exposure and musculoskeletal outcomes ». Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/2353.
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The etiology of musculoskeletal outcomes associated with the use of information technology (IT) has predominately been defined by studies of adults in their work environments. Theories explaining the causation of work related musculoskeletal disorders have identified individual user (biomechanical, physiological and psychosocial), task demand, work organization and environmental risk factors. Models based on these theories have subsequently been developed to investigate the causal relationship between IT exposure and outcomes experienced by the user.Computers are an important IT type used by children, and computer use by children is rapidly growing in both school and home environments. Recent literature demonstrates an increase in children’s reports of computer related musculoskeletal outcomes. Children’s computer use appears to be different to adult’s work related computer use. Thus, although many potential risk factors for children may be similar to those for adults, it is proposed that risk factors and models of causal relationships between computer use and musculoskeletal outcomes may vary for children.The main aims of this study were: (1) to investigate children’s computer exposure in their usual occupational environments of school and home; and (2) to develop and test a multivariable model that would assist in understanding relationships between child user correlates, computer exposure and computer related musculoskeletal outcomes.1351 students (792 boys and 559 girls) from eight primary and five secondary schools in Perth, Australia, participated in the study in 2006. Convenience sampling was undertaken within stratified groups, to ensure the sample had the required range of participants from different socioeconomic status (SES) backgrounds, both genders and school Years 1, 6, 9 and 11(approximate ages 6, 9, 14 and 16 years).The study design was cross sectional involving the completion of a questionnaire survey by participants, and for younger participants their parents. Questionnaires contained items relating to the participant and their activity exposure as an individual, within a family context, and within their neighbourhood. Physical measures of height and weight were also collected.The results showed that 100% of children had access to computers at school, and at home 98.9% of children had access to computers, with 95.9% reporting home internet access. The use of different exposure measures demonstrated that at school 97.8% of children had used a computer in the last month, for an average of 2.4 hours per week, commonly for 30-60 minutes in one sitting. At home 95.7% of children had used a computer in the last month, for an average of 7.2 hours per week, commonly for 60 - 120 minutes in one sitting. Computer activities performed more frequently at school were surfing the internet, learning programs and multimedia. At home the most frequent computer activities were surfing the internet and email. Children with bedroom computer access were found to have nearly 50% greater mean weekly hours of use. The use of a range of computer exposure measures (frequency, usual and longest duration, mean weekly hours and frequency of computer activities) provided better characterization of the amount and nature of children’s school and home computer exposure.Age and gender were associated with children’s school and home computer use. Computer use was greater with age for both boys and girls, and boys had greater use than girls across all Year levels for all exposure measures except school usual duration. Children with greater computer exposure were shown to experience less computer anxiety; reported more somatic complaints; had used a broader range of computer activities; had greater exposure to other IT activities (electronic games, TV, mobile phone) and moderate vigorous physical activity. SES was associated with computer exposure, with children from low SES backgrounds having greater home computer exposure, and children from high SES backgrounds having greater school computer exposure.Computer related musculoskeletal outcomes were reported by 10% of children for school computer use and 20% for home computers. The most commonly affected body locations were the neck and back, and 30% of those children reporting outcomes limited their activity participation, 10% took medication and 7% consulted a treating health professional. The use of a range of outcome measures allowed for a better understanding of the impact of children’s computer related musculoskeletal outcomes.Given the significant findings of different relationships between children’s computer exposure patterns at school and home, two models were developed and tested, with one model for school computer exposure and one model for home computer exposure. Path analysis modeling, accounting for user correlates, tested direct relationships and indirect relationships via computer exposure for a range of user correlates. The final school computer exposure model showed direct relationships between gender, somatic complaints, computer exposure and musculoskeletal soreness; and indirect relationships, via computer exposure, between age, computer flow, TV exposure, SES and musculoskeletal soreness. The final home computer exposure model showed direct relationships between gender, age, somatic complaints, computer exposure and musculoskeletal soreness; and indirect relationships, via computer exposure, between age, computer flow, computer anxiety, TV exposure, SES and musculoskeletal soreness.In conclusion, the child specific model tested within this study demonstrated direct relationships between children’s computer exposure and musculoskeletal outcomes. Additionally, direct and indirect relationships were also shown between a range of user correlates, the environment and musculoskeletal outcomes. These findings will assist researchers, teachers and parents to understand the range of potential risk factors for computer related musculoskeletal outcomes. This will also allow researchers to target interventions to child users and their computer environments to ensure children’s computer use is performed in a safe and productive manner.
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Ilg, Liesa, Manousos Klados, Nina Alexander, Clemens Kirschbaum et Shu-Chen Li. « Long-term impacts of prenatal synthetic glucocorticoids exposure on functional brain correlates of cognitive monitoring in adolescence ». Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-236971.
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The fetus is highly responsive to the level of glucocorticoids in the gestational environment. Perturbing glucocorticoids during fetal development could yield long-term consequences. Extending prior research about effects of prenatally exposed synthetic glucocorticoids (sGC) on brain structural development during childhood, we investigated functional brain correlates of cognitive conflict monitoring in term-born adolescents, who were prenatally exposed to sGC. Relative to the comparison group, behavioral response consistency (indexed by lower reaction time variability) and a brain correlate of conflict monitoring (the N2 event-related potential) were reduced in the sGC exposed group. Relatedly, source localization analyses showed that activations in the fronto-parietal network, most notably in the cingulate cortex and precuneus, were also attenuated in these adolescents. These regions are known to subserve conflict detection and response inhibition as well as top-down regulation of stress responses. Moreover, source activation in the anterior cingulate cortex correlated negatively with reaction time variability, whereas activation in the precuneus correlated positively with salivary cortisol reactivity to social stress in the sGC exposed group. Taken together, findings of this study indicate that prenatal exposure to sGC yields lasting impacts on the development of fronto-parietal brain functions during adolescence, affecting multiple facets of adaptive cognitive and behavioral control.
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Gavrilovici, Ovidiu. « EXPOSURE TO VIOLENCE AND ITS PSYCHOLOGICAL CORRELATES IN INSTITUTIONALIZED CHILDREN AND ADOLESCENTS 8 TO 17 YEARS OF AGE IN IASI COUNTY, ROMANIA ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1074852094.
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Bergstrom, Hadley C. « Lateralized dendritic correlates of enhanced conditioned fear retrieval following cessation from chronic nicotine exposure in adolescent and adult rats ». Fairfax, VA : George Mason University, 2009. http://hdl.handle.net/1920/4511.
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Thesis (Ph.D.)--George Mason University, 2009.Vita: p. 118. Thesis director: Robert F. Smith. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Psychology. Title from PDF t.p. (viewed June 10, 2009\). Includes bibliographical references (p. 101-117). Also issued in print.
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PINTORI, NICHOLAS. « “DIFFERENTIAL ADAPTIVE PROPERTIES OF MESOLIMBIC AND MESOCORTICAL DOPAMINE TRANSMISSION TO TASTE STIMULI, NEUROINFLAMMATORY EFFECTS AND BEHAVIORAL CORRELATES AFTER REPEATED EXPOSURE TO THE SYNTHETIC CANNABINOID JWH-018” ». Doctoral thesis, Università degli Studi di Cagliari, 2019. http://hdl.handle.net/11584/260587.
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Since 2004, herbal mixtures broadly known as Spice/K2, containing synthetic cannabinoids (SC) such as JWH-018, have been marketed as a legal marijuana surrogate. Previous studies of our group showed that JWH-018 has CB1-receptor dependent reinforcing properties and increases dopamine (DA) transmission selectively in the shell of the nucleus accumbens (NAc) at the dose of 0.25 mg/kg i.p. (De Luca et al., 2015). Other studies showed that taste stimuli increase extracellular DA in the NAc and in the medial prefrontal cortex (mPFC) of rats; this effect shows single-trial habituation in NAc shell but not in core or in mPFC (Bassareo et al., 2002). However, the selective disruption of mPFC by 6-OHDA lesions, abolishes habituation of DA responsiveness to taste stimuli in NAc shell (Bimpisidis et al., 2013). Such findings support the hypothesis of an inhibitory influence of mPFC on NAc DA, suggesting a top-down control of NAc DA by mPFC and its putative role in the loss of control of the motivational value of stimuli and in impulsivity (De Luca, 2014). In order to test if the repeated administration of JWH-018 is able to modulate the activity of DA terminal areas and is associated to changes in the responsiveness to motivational taste stimuli, adult male Sprague Dawley (SD) rats were administered once a day for 14 consecutive days with JWH-018 (0.25 mg/kg i.p.) or with vehicle. During the last day of administration, DA was quantified by in vivo brain microdialysis in the NAc and in the mPFC. JWH-018 repeated exposure decreases the sensitivity of NAc shell DA to the last JWH-018 administration. After a week of washout, DA was quantified in NAc shell, NAc core and mPFC of rats either naive or pre-exposed to chocolate (1 ml/5 min i.o.). JWH-018 administration decreases the sensitivity of NAc shell DA in naive rats, abolished habituation of DA responsiveness to repeated chocolate exposure in the NAc shell while induced it in the mPFC, suggesting a possible loss of control of the motivational value of stimuli. In the NAc core, JWH-018 treatment potentiated, delayed and prolonged the stimulatory DA response to taste stimuli of animals pre-exposed to chocolate. Parallel studies showed that repeated JWH-018 exposure reduces either spontaneous activity or number of VTA DA neurons, together with an increase of obsessive-compulsive/anxious behavior, attentional deficits, and signs of withdrawal. These data show that JWH-018 is able to change the activity of DA neurons and to induce differential adaptive changes of the responsiveness of DA transmission to taste stimuli in DA terminal areas, similarly to previous results obtained in mPFC 6-OHDA lesioned rats. Interestingly, these neurochemical and behavioral observation are associated with a neuroinflammatory phenotype, as indicated by IBA-1 immunoreactivity and reactive astrogliosis (GFAP) in DA brain areas. Therefore, JWH-018 induces behavioral effects and changes of glial cells (astrocytes and microglia), which might be related to the central effects observed after repeated JWH-018 administration. Taken together these results suggest that JWH-018 repeated treatment may reflect a model of addiction, and this study could be useful to understand if dysfunctions of cortical-limbic-striatal DA circuit, as well as glial cells alterations, can lead or are related to specific detrimental effects of recurring use of Spice/K2 drugs.
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Lin, Fang-Chia, et 林芳佳. « Exposure to Polycyclic Aromatic Hydrocarbons (PAHs) Correlated with Oxidative Stress among Municipal Waste Incinerator Workers ». Thesis, 2016. http://ndltd.ncl.edu.tw/handle/06589783391003688755.
Texte intégralRésumé :
碩士國立陽明大學
環境與職業衛生研究所
104
In recent years, researches have shown that the emitting pollutant from incinerator caused health effects of residents living near community. Meanwhile, workers in incinerator has more likelihood exposure to high levels of pollutants, such dioxin, various metals and polyaromatic hydrocarbon (PAH) etc. The objective of this study is to explore the association between levels of PAH metabolites in urine and oxidative stress. Total of 83 participants from employees in an incinerator, workplace of staffs nearly connected with incinerator plant, and residents living in the vicinity of the incinerator. Each participant was interviewed by a structured questionnaire and collected two urine specimens during pre-shift and post-shift. Urinary1-OHP (1-hydroxypyrene) and 3-OHBaP (3- hydroxybenzo (a) pyrene), respectively represent exposure to pyrene (Pyr) and benzo (a) pyrene (BaP),were analyzed by HPLC-Fluorescence and use the nonparametric statistics analysis. After adjusting for age, gender,educational level,smoke, incense, the result of multiple logistic regression showed that urinary 1-OHP level in high exposure group (HEG) was significantly higher in low exposure group (LEG)(p=0.01) .Similarly, urinary 3-OHP levels in HEG were significantly higher in LEG(p=0.02). Generally speaking, 3-OHBaP levels in urine were considerably higher in post-shift period, but not found in urinary 1-OHP levels. After adjusting for age, gender,educational level,smoke, incense, the result of multiple logistic regression showed that urinary PAH metabolites level was significantly related to MDA concentration , meaning urinary MDA levels affected by PAH exposures. Meanwhile, urinary PAHs metabolite levels also affected by smoking and use of personal protective equipment. We concluded workers in the incinerator showed high levels of PAH metabolites in urine exposure due to exposure to PAH in workplace. As a consequence, it is ii necessary to alleviate the emission of PAH from various processes in incinerator and to effectively reduce risk of PAH exposure by installing isolation area and by monitoring workers worn personal protective equipment.
Livres sur le sujet "Correlated Exposure"
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Wright, A. G. Signal-induced background. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199565092.003.0011.
Texte intégralRésumé :
Signal-induced background has a time dependence that distinguishes it from the sources discussed in Chapter 6. These events refer to a progression in which a signal generates a subsequent one, correlated in time to the initial detection. The timescale for correlated background ranges from nanoseconds to days. The earliest signal is a prepulse generated by a photon incident on d1. Late pulses relate to the k-to-d1, and k-to-anode transit time. The next category, the afterpulses, spans ~100 ns to 10 μs, with a peaked time distribution. There is a long-lived source of photons, extending to days and caused by exposure of a photomultiplier to bright light or to nuclear radiation. Afterpulses contribute to the slope of a photon-counting plateau characteristic, distort fluorescent decay, and pulse shape discrimination measurements. They also affect resolution, and processes of a statistical nature.
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Russell, Cristel Antonia, Dale W. Russell et Joel W. Grube. Substance Use and the Media. Sous la direction de Kenneth J. Sher. Oxford University Press, 2015. http://dx.doi.org/10.1093/oxfordhb/9780199381678.013.19.
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This chapter reviews the research relating to substance use portrayals and marketing in media. Research suggests that alcohol and tobacco marketing through traditional advertising, but also through product placements in film and television and other new forms of promotion, are prevalent. Youth may be especially exposed to these marketing efforts. New interactive electronic media, including social media, mobile phones, and games are increasingly important marketing tools. Overall, there is good evidence that exposure to tobacco marketing and portrayals are related to smoking behaviors, especially among youth. Evidence regarding exposure to alcohol marketing and portrayals also indicates that it is correlated with drinking behaviors among youth. Less is known about the effects of exposure to other substance use portrayals or about new media. There is some evidence that social marketing through media campaigns or entertainment media may have socially desirable effects. Future research should focus on emerging media and marketing techniques.
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Massey, Douglas S., et Brandon Wagner. Segregation, Stigma, and Stratification : A Biosocial Model. Sous la direction de Brenda Major, John F. Dovidio et Bruce G. Link. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780190243470.013.14.
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This chapter reviews research on segregation’s effect in generating concentrated poverty and stigma, and it explores the biological consequences of exposure to these conditions for health and socioeconomic status. High levels of segregation interact with high levels of poverty to produce concentrated poverty for African Americans and Hispanics in many metropolitan areas. In addition to objective circumstances of deprivation, the concentration of poverty also brings about the stigmatization of the segregated group. The differential exposure of Blacks and Hispanics to concentrated neighborhood disadvantage and its correlates, in turn, functions to shorten telomeres, increase allostatic load, and alter gene expression in deleterious ways. In so doing, it compromises health and cognitive ability, the two critical components of human capital formation, thus systematically undermining the socioeconomic prospects of African Americans and Hispanics in today’s post-industrial, information economy.
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Simon, Gleeson. Part I The Elements of Bank Financial Supervision, 1 Introduction to Banks and Banking. Oxford University Press, 2018. http://dx.doi.org/10.1093/law/9780198793410.003.0001.
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This chapter discusses the basic concepts of banks and banking. A bank is an institution that accepts deposits from the public and lends the monies thus raised. However, bank balance sheets include a range of types of exposures to a range of types of counterparties, which give rise to risks. To minimize risks, most banks diversify their lending across a number of different strategies and types of business. Both managers and regulators of banks have a task which in principle is relatively straightforward. These include understanding exactly which risks the bank is in fact exposed to; quantifying those risks; assessing returns which may be obtained through the taking of those risks; and assessing the degree to which the risks to which they are exposed are correlated to each other, in order to establish the total risk which is faced by the institution as a whole.
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Hughes, Jeremy. Proteinuria as a direct cause of progression. Sous la direction de David J. Goldsmith. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199592548.003.0137.
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Proximal tubular cells reabsorb any filtered proteins during health via cell surface receptors such as megalin and cubulin so that very low levels of protein are present in the excreted urine. Significant proteinuria is a common finding in patients with many renal diseases. Proteinuria is a marker of glomerular damage and podocyte loss and injury in particular. The degree of proteinuria at presentation or during the course of the disease correlates with long-term outcome in many renal diseases. Proteinuria per se may be nephrotoxic and thus directly relevant to the progression of renal disease rather than simply acting as a marker of the severity of glomerular injury and podocytes loss. Seminal studies used the atypical renal anatomy of the axolotl to instill proteins directly into the tubular lumen without requiring passage through the glomerulus. This indicated that tubular protein could be cytotoxic and induce interstitial inflammation and fibrosis in the peritubular region. Cell culture studies demonstrate that exposure to proteins results in proximal tubular cell activation and the production of pro-inflammatory and pro-fibrotic mediators. Proximal tubular cell death occurred in some studies reinforcing the potential of protein to exert cytotoxic effects via oxidative stress or endoplasmic reticulum stress. Analysis of renal biopsy material from both experimental studies using models of proteinuric disease or patients with various proteinuric diseases provided evidence of activation of transcription factors and production of chemokines and pro-inflammatory mediators by proximal tubular cells. These data strongly suggest that although proteinuria is the result of glomerular disease it also represents an important cause of progression in patients with chronic kidney disease associated with proteinuria.
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McShane, Tony, Peter Clayton, Michael Donaghy et Robert Surtees. Neurometabolic disorders. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780198569381.003.0213.
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Various disorders result from genetically determined abnormalities of enzymes, the metabolic consequences of which affect the development or functioning of the nervous system. The range of metabolic disturbances is wide, as is the resultant range of clinical syndromes. Although most occur in children, some can present in adult life, and increasing numbers of affected children survive into adult life. In some, specific treatments are possible or are being developed. The last 20 years has seen a considerable expansion in our understanding of the genetic and metabolic basis for many neurological conditions. Particular clinical presentations of neurometabolic disorders include ataxias, movement disorders, childhood epilepsies, or peripheral neuropathy. Detailed coverage of the entire range of inherited metabolic diseases of the nervous system is available in other texts (Brett 1997; Scriver et al. 2001; Menkes et al. 2005).Treatment is possible for some metabolic diseases. For instance, the devastating neurological effects of phenylketonuria have been recognized for many years. Neonatal screening for this disorder and dietary modification in the developed world has removed phenylketonuria from the list of important causes of serious neurological disability in children. This success has led to new challenges in the management of the adult with phenylketonuria and unexpected and devastating effect of the disorder on the unborn child of an untreated Phenylketonuria mother. More recently Biotinidase deficiency has been recognized as an important and easily treatable cause of serious neurological disease usually presenting with early onset drug resistant seizures. This and some other neurometabolic diseases can be identified on neonatal blood screening although a full range of screening is not yet routine in the United Kingdom. More disorders are likely to be picked up at an earlier asymptomatic stage as the sophistication of screening tests increases (Wilcken et al. 2003; Bodamer et al. 2007).Although individual metabolic disorders are rare, collectively such disorders are relatively common. In reality most clinicians will see an individual condition only rarely in a career. Furthermore, patients with certain rare conditions are often concentrated in specialist referral centres, further reducing the exposure of general and paediatric neurologists to these disorders. A recent study into progressive intellectual and neurological deterioration, PIND, gives some information about the relative frequency and distribution of some childhood neurodegenerative diseases in the United Kingdom (Verity et al. 2000; Devereux et al. 2004). Although primarily designed to identify any childhood cases of variant Creutzfeldt- Jakob disease, the study also provided much information about the distribution of neurometabolic disease in children in the United Kingdom. The commonest five causes of progressive intellectual and neurological deterioration over 5 years were Sanfilippo syndrome, 41 cases, adrenoleukodystrophy, 32 cases, late infantile neuronal ceroid lipofuschinosis, 32 cases, mitochondrial cytopathy, 30 cases, and Rett syndrome, 29 cases. Notably, geographical foci of these disorders were also found and correlate with high rate of consanguinity in some local populations.
Chapitres de livres sur le sujet "Correlated Exposure"
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Naumova, Elena N., Timothy C. Haas et Robert D. Morris. « Estimation of Individual Exposure Following a Chemical Spill in Superior, Wisconsin ». Dans Modelling Longitudinal and Spatially Correlated Data, 243–54. New York, NY : Springer New York, 1997. http://dx.doi.org/10.1007/978-1-4612-0699-6_21.
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Saturno, Jacopo. « Strategie di formazione delle parole in varietà iniziali di polacco L2 ». Dans Le lingue slave tra struttura e uso, 279–303. Florence : Firenze University Press, 2016. http://dx.doi.org/10.36253/978-88-6453-328-5.16.
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This paper describes word formation as observed in the earliest stages of L2 Polish. 31 L1 Italian beginning learners took part in a 14-hour Polish course, which was recorded, transcribed and morphologically tagged in order to correlate learner output with the relevant input features. After 4:30 hours, the learners could produce new words using the derivational suffix -k-, which in the input can be found in the majority of feminine nouns. This finding suggests that after minimal exposure, learners can identify the morphological structure of a class of nouns and reproduce it in their output.
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Rey, Beatriz, Vera Parkhutik, José Tembl et Mariano Alcañiz. « Analyzing Neural Correlates of Attentional Changes during the Exposure to Virtual Environments : Application of Transcranial Doppler Monitoring ». Dans Foundations of Augmented Cognition. Directing the Future of Adaptive Systems, 212–20. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-21852-1_27.
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Matić, Gordana, Danijela Vojnović Milutinović, Ivana Elaković, Jelena Nestorov et Danka Savić. « Level of Expression and Functional Properties of Lymphocyte Corticosteroid Receptors as Biological Correlates of PTSD, Trauma-Exposure, or Resilience to PTSD ». Dans Comprehensive Guide to Post-Traumatic Stress Disorders, 961–78. Cham : Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-08359-9_3.
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Matić, Gordana, Danijela Vojnović Milutinović, Ivana Elaković, Jelena Nestorov et Danka Savić. « Level of Expression and Functional Properties of Lymphocyte Corticosteroid Receptors as Biological Correlates of PTSD, Trauma-Exposure or Resiliance to PTSD ». Dans Comprehensive Guide to Post-Traumatic Stress Disorder, 1–16. Cham : Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-08613-2_3-1.
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Pop-Eleches, Grigore, et Joshua A. Tucker. « Social Welfare ». Dans Communism's Shadow. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691175591.003.0006.
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This chapter examines the mechanisms underlying the greater support for an active welfare state among residents of post-communist countries. The analysis found very strong evidence that additional years of exposure to communist rule were correlated with greater support for state responsibility for social welfare. Moreover, and in line with the findings from the preceding two chapters, this chapter also shows that adult communist exposure has a greater impact on welfare state attitudes than childhood exposure. However, unlike in the previous two chapters, it appears that the attitudinal imprint of communism affects not only individuals with long personal exposures to communism but also post-communist citizens with very limited personal exposures to communist regimes and welfare states.
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Haj-Yahia, Muhammad M., et Charles W. Greenbaum. « Prolonged Exposure to Political Violence and the Development of Post-Traumatic Stress Symptoms in Palestinian Adolescents ». Dans Handbook of Political Violence and Children, 189–220. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190874551.003.0007.
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This chapter investigates the relationship between prolonged exposure to political violence (EPV) and post-traumatic stress symptoms (PTSS) among Palestinian adolescents. It also examines the moderating effect of participants’ age, gender, and parental socialization styles on the relationship between EPV and PTSS. A systematic cluster random sample of 2,934 Palestinian adolescents aged 14 to 19 years living in the West Bank and East Jerusalem responded to self-administered questionnaires. Multiple regression analysis showed a positive relationship between levels of EPV and of PTSS. Girls showed higher levels of PTSS than boys. Hostile and rejecting parenting styles, strict discipline, and negative evaluation from parents correlated positively with high PTSS, whereas intimate and loving parenting correlated with low levels of PTSS, supporting the hypotheses presented here. The chapter discusses the importance of intimate and loving parenting styles as a possible protective factor for mitigating the effects of political violence on children.
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Guarascio, Dario, et Stefano Sacchi. « Technology, Risk, and Support for Social Safety Nets. An Empirical Exploration Based on Italy ». Dans Digitalization and the Welfare State, 192–213. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192848369.003.0011.
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This chapter investigates the role of exposure to technological risk in shaping social policy preferences, specifically on support for universal basic income and means-tested guaranteed minimum income. Evidence is provided for Italy, to exploit the availability of high-quality data, allowing measures of two dimensions of technological risk. Objective risk hinges upon the degree of substitutability of one’s occupation by machines, while subjective risk concerns a worker’s perception of their substitutability. We posit that exposure to technological risk induces individuals to ask for protection, and thus increases support for social policy. We test two hypotheses: first, that exposure to objective risk of replacement by machines is correlated with support for both safety nets; second, that such effect is increased by high perception of risk. On the whole, results confirm a strong relationship between exposure to technological risk and support for social safety nets, once objective risk is disentangled from subjective perceptions.
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Aubrey, Jennifer Stevens, Leah Dajches et Larissa Terán. « Media as a Source of Sexual Socialization for Emerging Adults ». Dans Sexuality in Emerging Adulthood, 312–32. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780190057008.003.0019.
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This chapter examines the role of three medium types—television and films, music and music videos, and pornography—in the sexual socialization of emerging adults. For television/films and music/music videos, researchers have found that increased exposure to both is associated with more gendered sexual beliefs and more sexually permissive attitudes and expectations. There is also evidence that exposure to mainstream television and movies is related to a variety of sexual behaviors, including age at sexual debut, sexual experience, and risky sexual behaviors. The literatures on music/music videos and pornography share a common interest in sexism, reporting that both types of media exposure are related to sexist beliefs and lax perceptions of sexual aggression. Pornography consumption is also correlated with more negative body image and higher relational dissatisfaction, which have consequences for the quality of emerging adults’ sexual experiences.
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Mann, J. John, et Dianne Currier. « Biological aspects of suicidal behaviour ». Dans New Oxford Textbook of Psychiatry, 963–69. Oxford University Press, 2012. http://dx.doi.org/10.1093/med/9780199696758.003.0123.
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To understand the biological underpinnings of multi-determined behaviours such as suicide and attempted suicide it is necessary to situate them within an explanatory model that can elaborate the causal pathways and interrelations between biological, clinical, genetic, and environmental factors that all play a role in suicidal behaviour. Where possible, such a model should be clinically explanatory, incorporate biological correlates, be testable in both clinical and biological studies, and have some utility in identifying high-risk individuals. We have proposed a stress–diathesis model of suicidal behaviour wherein exposure to a stressor precipitates a suicidal act in those with the diathesis, or propensity, for suicidal behaviour. Stressors are generally state-dependent factors such as an episode of major depression or adverse life event. The diathesis, we have hypothesized, comprises trait characteristics such as impulsive aggression, and pessimism. Uncovering the biological mechanisms relevant to the stress and the diathesis dimensions of suicidal behaviour will facilitate the identification of both enduring and proximal markers of risk, as well as potential targets for treatment. One biological correlate of the diathesis for suicidal behaviour appears to be low serotonergic activity. Abnormal serotonergic function may be the result of numerous factors including genetics, early life experience, chronic medical illness, alcoholism or substance use disorder, many of which have been correlated with increased risk for suicidal behaviour. Moreover, serotonergic dysfunction may underlie recurrent mood disorders or behavioural traits that characterize the diathesis, such as aggression and impulsivity. In terms of stress response, the noradrenergic and HPA axis have been the focus of biological studies in suicidal behaviour. This chapter gives an overview of the major neurobiological findings in suicide and attempted suicide, as well as emerging findings from studies of genes related to those systems.
Actes de conférences sur le sujet "Correlated Exposure"
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Kiel, Erlend Sando, et Gerd Hovin Kjolle. « Transmission line unavailability due to correlated threat exposure ». Dans 2019 IEEE Milan PowerTech. IEEE, 2019. http://dx.doi.org/10.1109/ptc.2019.8810845.
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Chena, Hsieh-Ching, Yu-Wen Chena, Yung-Ping Liub et Yi-Tsong Pan. « Quantitative Assessment of Computer Inputs and Musculoskeletal Complaints among Three Workgroups ». Dans Applied Human Factors and Ergonomics Conference. AHFE International, 2018. http://dx.doi.org/10.54941/10045.
Texte intégralRésumé :
Musculoskeletal disorders associated with computer use are closely related to the level of computer exposure. Various studies have been conducted for recording and evaluating long-term use of mouse and keyboard in computer workers. However, keyboard exposure is distributed over two hands and different fingers and mouse workload is mainly borne by the dominant hand which is with significantly higher musculoskeletal risk. This study utilizes an external logger for onsite measurements of computer activities in three professional groups over 6 months. All subjects include twelve university administrators, eight computer-aided design (CAD) draftsmen, and eight software programmers. Individual participant’s typing pattern was determined by a novel hardware and software developed in this study to separate keyboarding workload in the dominant hand from that in the nondominant hand. Each participant’s daily computer exposures, number of keystroke typing and mouse clicking, in one’s dominant and nondominant hand were then predicted by individual typing pattern and the logged computer activities. Estimated computer exposures of participants’ dominant and nondominant hand were then correlated with the musculoskeletal complaints collected by a questionnaire of body part discomfort rating. Regression analysis show participants’ average daily computer exposure was only moderately correlated with their hand discomfort. Research finding suggests computer associated discomfort may be affected by factors other than keyboard and mouse exposures.
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Woodward, Kelsey, Annalee Ellis, Jenni Teeters et Matthew Woodward. « Examining Associations Between Trauma Exposure and Cannabis Use Frequency, Quantity, Duration, and Age of Onset ». Dans 2020 Virtual Scientific Meeting of the Research Society on Marijuana. Research Society on Marijuana, 2021. http://dx.doi.org/10.26828/cannabis.2021.01.000.39.
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Prior research has identified an association between trauma exposure and cannabis use, such that a history of trauma exposure is associated with greater likelihood of lifetime cannabis use. However, little research has expanded upon this association, making it unclear whether trauma exposure is associated with cannabis use outcomes beyond lifetime history of use. Given that heavy cannabis use and trauma exposure are risk factors for a number of deleterious outcomes, it is important to further examine the influence of trauma exposure on cannabis use. The purpose of the current study was to further explore this relationship by examining associations between trauma exposure and various indices of cannabis use. Participants included a sample of 722 female undergraduates at least 18 years or older (M = 19.0) who were recruited through a campus-wide online study pool. Participants completed measures on trauma exposure (calculated as number of traumas experienced), cannabis use (i.e., Daily Sessions, Frequency, Age of Onset, and Quantity of Cannabis Use [DFAQ-CU]; Cutler & Spradlin, 2017), and mental health symptoms. Specific indices of cannabis use were lifetime history of cannabis use, age of onset of cannabis use, current frequency of use, current quantity of use (in grams), and length of use. Logistic regression analyses and correlations were used to explore the associations between trauma and cannabis use variables. Subsequent analyses were conducted controlling for posttraumatic stress disorder (PTSD) symptoms to determine whether relationships between trauma exposure and cannabis use remained after accounting for PTSD symptoms. Thirty-seven percent (n = 266) of the sample indicated a lifetime history of cannabis use. Similar to previous research, greater trauma exposure was significantly associated with a greater likelihood of a lifetime history of cannabis use (OR = 1.14, p < .001). Additionally, number of traumas experienced and age of onset of cannabis use were significantly negatively correlated, r(262) = -.16, p < .01, indicating that greater trauma exposure was associated with earlier onset of use. Number of traumas experienced was positively correlated with duration of cannabis use, r(236)=.14, p = .03, indicating greater trauma exposure was associated with greater duration of use. Number of traumas experienced was also positively correlated with quantity of cannabis use, r(175)=.20, p < .01, showing that greater trauma exposure was associated with higher amounts of cannabis used. These associations remained significant even after controlling for PTSD symptoms. Frequency of cannabis use was not significantly correlated with trauma exposure, r(266) = -.01, p = .82. The results of the present study indicate that trauma exposure is associated with a range of indices of cannabis use beyond lifetime history of use, even after accounting for the influence of PTSD. These findings highlight the importance of extending examination of trauma and cannabis beyond frequency of use. Although trauma exposure may serve as a risk factor for elevated cannabis use, it is also possible that cannabis use may increase the risk of trauma exposure. Future studies should explore these associations longitudinally as well as examine the mechanisms that link these outcomes together.
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Carlsen, Hanne Krage, David Olsson, Thorarinn Gislason, Johan Hellgren, Christer Janson, Ane Johannessen, Rain Jögi, Torben Sigsgaard et Bertil Forsberg. « Self-reported traffic exposure is not strongly correlated with modelled NOx in a Northern European cohort study ». Dans ERS International Congress 2016 abstracts. European Respiratory Society, 2016. http://dx.doi.org/10.1183/13993003.congress-2016.pa4287.
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Zhuang, Z., C. Coffey, J. Nicholson, B. Lawrence, G. Qiao, D. Campbell et P. Jensen. « 341. Evaluation of New Strategies for Measuring Freon-113 Exposure Dose to Be Correlated to Quantitative Fit Factor ». Dans AIHce 2001. AIHA, 2001. http://dx.doi.org/10.3320/1.2765876.
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Vasilyeva, Irina, O. Korytov, V. Bespalov, A. Semenov, G. Tochil'nikov, S. Ivanov et L. Korytova. « EFFECTS OF RADIATION EXPOSURE OF THE BLADDER ON EARLY CHANGES OF EXTRACELLULAR DNA AND OTHER INDICATORS OF PERIPHERAL BLOOD ». Dans XIV International Scientific Conference "System Analysis in Medicine". Far Eastern Scientific Center of Physiology and Pathology of Respiration, 2020. http://dx.doi.org/10.12737/conferencearticle_5fe01d9b37c7f8.86673968.
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On the model of radiation cystitis in rats, a decrease in the number of blood cells was found 6 h after local irradiation and an increase in extracellular DNA level was found in 6-24 h with normalization 48 h after exposure. The relative change in the content of extracellular DNA (0 h against 6 h) correlated with changes in triglycerides (0 h against 24 h).
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Patrick, Heather, et Sarah Gilbert. « Comparison of UV Photosensitivity and Fluorescence During Fiber Grating Formation ». Dans Photosensitivity and Quadratic Nonlinearity in Glass Waveguides. Washington, D.C. : Optica Publishing Group, 1995. http://dx.doi.org/10.1364/pqn.1995.sub.15.
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We have conducted a comparison of the UV photosensitivity of optical fiber with the blue fluorescence emitted during the exposure. In a survey of ten non-hydrogen-loaded germanium-doped fibers, we measured the UV photosensitivity and monitored the blue fluorescence during the growth of fiber gratings. Our goal was to determine whether the initial fluorescence, or the change in the fluorescence during exposure, is correlated with the index change. This provides insight into the underlying physical mechanism of UV-induced index change and also determines whether the blue fluorescence can be used as an indicator of the photosensitivity of a fiber.
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Morinaga, Masahiko, Tomoharu Fujii et Takeshi Takahashi. « Development of Actual TBC Exposure Temperature Prediction Method ». Dans ASME Turbo Expo 2004 : Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-53267.
Texte intégralRésumé :
Gas turbines are being operated at ever-higher temperatures in order to increase their efficiency. As a result, thermal barrier technology to protect the gas turbine hot gas path parts from high-temperature combustion gas is becoming increasingly important, making it necessary to evaluate the thermal barrier performance of the thermal barrier coating (TBC) coated on these gas turbine hot gas path parts. Thermal barrier performance of the TBC deteriorates with the number of operating hours of the gas turbine. The degradation of TBC thermal barrier performance raises substrate temperature, and this rise in substrate temperature reduces the remaining life of the substrate. We proposed an effective nondestructive inspection (NDI) method to evaluate the thermal barrier performance of the TBC by infrared transient heating of the TBC surface. The temperature behavior closely correlated with the thermal barrier performance of the TBC. The results of numerical analysis and laboratory tests showed that the proposed NDI method was effective for evaluating the thermal barrier performance of TBC. So we developed NDI apparatus to inspect the thermal barrier performance of actual combustion liner TBC. In this NDI apparatus, the surface of the TBC was heated using a CO2 laser, and the temperature of the heated surface measured using an infrared camera. The CO2 laser and infrared camera were fixed, while the measured combustion liner was traversed continuously. The NDI apparatus developed enabled us to inspect the whole inner surface of an actual gas turbine combustion liner. We also showed the correlation with thermal conductivity of a virgin TBC, thermal conductivity of an inspected TBC, operating hours and TBC exposure temperature in our TBC thermophysical property study. The combination of this method and the NDI apparatus developed proved an effective way of clarifying the operating temperature of the hot gas path parts of the gas turbine. In this paper, we show a method for predicting actual gas turbine TBC exposure temperature, important when evaluating the remaining life of gas turbine substrate by the NDI apparatus developed and method of predicting TBC exposure temperature.
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Lindon, J. N., L. Kushner, E. Shiba et E. W. Salzman. « PLATELET ADHESION ON SYNTHETIC SURFACES PRETREATED WITH DILUTED PLASMA IS DETERMINED BY THE SURFACE CONCENTRATION OF "NATIVE" FIBRINOGEN ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643551.
Texte intégralRésumé :
Platelet adhesion and activation on synthetic surfaces are thought to require the prior adsorption of fibrinogen. We have reported that platelet activation by polyalkyl methacrylates (measured in bead columns exposed to flowing blood) is better correlated with the concentration of conformationally unaltered, "native" (recognizable by radiolabeled antifibrinogen antibodies) bound fibrinogen than with total bound fibrinogen (measured with radiolabeled fibrinogen) following exposure of the surfaces to purified fibrinogen in solution or to diluted blood plasma (Blood 68:355, 1986). We now report that adhesion of washed platelets to polybutyl methacrylate (PBMA; approx. 20% retention in bead columns), was unaffected by preincubation of the surface with whole plasma but was increased significantly by precoating with diluted plasma, with maximum retention (approx. 65%) occurring with plasma diluted 3000-fold. Upon exposure of PBMA to various plasma dilutions the surface concentration of antibody-detectable fibrinogen, but. not of total surface-bound fibrinogen, was correlated with the activation of washed platelets by such pretreated surfaces, With maximal platelet reactivity occurring in columns precoated with the plasma dilution (1:3000) that produced the highest concentration of "native" surface-bound fibrinogen. The plasma dilution that gave maximum total fibrinogen adsorption (100-fold dilution) was not correlated with the concentration of antibody-detectable fibrinogen. Fab fragments of polyclonal anti-fibrinogen antibodies totally prevented platelet activation by PBMA surfaces precoated with diluted plasma. It appears that participation of surface-bound fibrinogen in platelet activation on some artificial surfaces requires that fibrinogen be adsorbed in a conformationally "native" state, presumably thereby permitting multivalent, cooperative interactions with GP IIb/IIIa receptors on platelets.
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Li, Kun, Kensuke Sasaki, Soichi Watanabe et Kanako Wake. « Averaging Area for Transmitted Power Density Correlated to Temperature Elevation on Human Skin Surface due to RF Exposure at 60 GHz ». Dans 2019 IEEE MTT-S International Microwave Biomedical Conference (IMBioC). IEEE, 2019. http://dx.doi.org/10.1109/imbioc.2019.8777894.
Texte intégralRapports d'organisations sur le sujet "Correlated Exposure"
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Avila-Montealegre, Oscar, et Carter Mix. Common Trade Exposure and Business Cycle Comovement. Banco de la República de Colombia, décembre 2020. http://dx.doi.org/10.32468/be.1149.
Texte intégralRésumé :
A large empirical literature has shown that countries that trade more with each other have more correlated business cycles. We show that previous estimates of this relationship are biased upward because they ignore common trade exposure to other countries. When we account for common trade exposure to foreign business cycles, we find that (1) the effect of bilateral trade on business cycle comovement falls by roughly 25 percent and (2) common exposure is a significant driver of business cycle comovement. A standard international real business cycle model is qualitatively consistent with these facts but fails to reproduce their magnitudes. Past studies have used models that allow for productivity shock transmission through trade to strengthen the relationship between trade and comovement. We find that productivity shock transmission increases business cycle comovement largely because of a country-pair's common trade exposure to other countries rather than because of bilateral trade. When we allow for stronger transmission between small open economies than other country-pairs, comovement increases both from bilateral trade and common exposure, similar to the data.
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Hanna, Rema, Bridget Hoffmann, Paulina Oliva et Jake Schneider. The Power of Perception : Limitations of Information in Reducing Air Pollution Exposure. Inter-American Development Bank, juillet 2021. http://dx.doi.org/10.18235/0003392.
Texte intégralRésumé :
We conduct a randomized controlled trial in Mexico City to determine willingness to pay (WTP) for SMS air quality alerts and to study the effects of air quality alerts, reminders, and a reusable N95 mask on air pollution information and avoidance behavior. At baseline, we elicit WTP for the alerts service after revealing whether the household will receive an N95 mask and participant compensation, but before revealing whether they will receive alert or reminder services. While we observe no significant impact of mask provision on WTP, higher compensation increases WTP, suggesting a possible cash-on-hand constraint. The perception of high pollution days prior to the survey is positively correlated with WTP, but the presence of actual high pollution days is not correlated with WTP. Follow-up survey data demonstrate that the alerts treatment increases reporting of receiving air pollution information via SMS, a high pollution day in the past week, and staying indoors on the most recent perceived high pollution day. However, we observe no significant effect on the ability to correctly identify which specific days had high pollution. Similarly, households that received an N95 mask are more likely to report utilizing a mask with filter in the past two weeks, but we observe no effect on using a filter mask on the specific days with high particulate matter. Although we nd that air quality alerts increased the salience of air quality and avoidance behavior, these results illustrate the difficulty that information treatments face in overcoming perceptions to effectively reduce exposure to air pollution.
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Hourani, Laurel, et Susan Hilton. Occupational and Environmental Exposure Correlates of Adverse Live-Birth Outcomes Among 1,032 U.S. Navy Women. Fort Belvoir, VA : Defense Technical Information Center, juin 1999. http://dx.doi.org/10.21236/ada381317.
Texte intégral
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Hourani, Laurel L., Huixing Yuan et Robert M. Bray. Psychosocial and Health Correlates of Types of Traumatic Event Exposures Among U.S. Military Personnel. Fort Belvoir, VA : Defense Technical Information Center, septembre 2003. http://dx.doi.org/10.21236/ada419553.
Texte intégral
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Samach, Alon, Douglas Cook et Jaime Kigel. Molecular mechanisms of plant reproductive adaptation to aridity gradients. United States Department of Agriculture, janvier 2008. http://dx.doi.org/10.32747/2008.7696513.bard.
Texte intégralRésumé :
Annual plants have developed a range of different mechanisms to avoid flowering (exposure of reproductive organs to the environment) under adverse environmental conditions. Seasonal environmental events such as gradual changes in day length and temperature affect the timing of transition to flowering in many annual and perennial plants. Research in Arabidopsis and additional species suggest that some environmental signals converge on transcriptional regulation of common floral integrators such as FLOWERING LOCUS T (FT). Here we studied environmental induction of flowering in the model legume Medicago truncatula. Similarly to Arabidopsis, the transition to flowering in M. truncatula is hastened by long photoperiods and long periods of vernalization (4°C for 2-3 weeks). Ecotypes collected in Israel retain a vernalization response even though winter temperatures are way above 4°C. Here we show that this species is also highly responsive (flowers earlier) to mild ambient temperatures up to 19°C simulating winter conditions in its natural habitat. Physiological experiments allowed us to time the transition to flowering due to low temperatures, and to compare it to vernalization. We have made use of natural variation, and induced mutants to identify key genes involved in this process, and we provide here data suggesting that an FT gene in M.truncatula is transcriptionally regulated by different environmental cues. Flowering time was found to be correlated with MtFTA and MtFTB expression levels. Mutation in the MtFTA gene showed a late flowering phenotype, while over-expressing MtFTA in Arabidopsis complemented the ft- phenotype. We found that combination of 4°C and 12°C resulted in a synergistic increase in MtFTB expression, while combining 4°C and long photoperiods caused a synergistic increase in MtFTA expression. These results suggest that the two vernalization temperatures work through distinct mechanisms. The early flowering kalil mutant expressed higher levels of MtFTA and not MtFTB suggesting that the KALIL protein represses MtFTA specifically. The desert ecotype Sde Boker flowers earlier in response to short treatments of 8-12oc vernalization and expresses higher levels of MtFTA. This suggests a possible mechanism this desert ecotype developed to flower as fast as possible and finish its growth cycle before the dry period. MtFTA and FT expression are induced by common environmental cues in each species, and expression is repressed under short days. Replacing FT with the MtFTA gene (including regulatory elements) caused high MtFTA expression and early flowering under short days suggesting that the mechanism used to repress flowering under short days has diversified between the two species.The circadian regulated gene, GIGANTEA (GI) encodes a unique protein in Arabidopsis that is involved in flowering mechanism. In this research we characterized how the expression of the M.truncatula GI ortholog is regulated by light and temperature in comparison to its regulation in Arabidopsis. In Arabidopsis GI was found to be involved in temperature compensation to the clock. In addition, GI was found to be involved in mediating the effect of temperature on flowering time. We tested the influence of cold temperature on the MtGI gene in M.truncatula and found correlation between MtGI levels and extended periods of 12°C treatment. MtGI elevation that was found mostly after plants were removed from the cold influence preceded the induction of MtFT expression. This data suggests that MtGI might be involved in 12°C cold perception with respect to flowering in M.truncatula. GI seems to integrate diverse environmental inputs and translates them to the proper physiological and developmental outputs, acting through several different pathways. These research enabled to correlate between temperature and circadian clock in M.truncatula and achieved a better understanding of the flowering mechanism of this species.
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Freeman, Stanley, et Russell J. Rodriguez. The Interaction Between Nonpathogenic Mutants of Colletotrichum and Fusarium, and the Plant Host Defense System. United States Department of Agriculture, septembre 2000. http://dx.doi.org/10.32747/2000.7573069.bard.
Texte intégralRésumé :
The intent of this proposal was to study the interaction between nonpathogenic mutants of Colletotrichum magna and Fusarium oxysporum, and the cucurbit host defense system. We had shown previously that a nonpathogenic endophytic mutant path- 1 of C. magna, caused no visible disease symptoms but protected watermelon seedlings from disease caused by the wildtype isolate and F. o. niveum. Objectives were: 1) Determine the microscopic, biochemical and molecular genetic interaction between "protected" (path- 1 colonized) cucurbit hosts and wildtype isolates of C. magna; 2) Isolate non-pathogenic mutants of F.o. melonis and test feasibility for protecting plants against fungal diseases. We found that path-1 caused no visible disease symptoms in cucurbit seedlings but conferred disease resistance against pathogenic isolates of C. magna, C. orbiculare, and F. oxysporum. Disease resistance conferred by path-1 correlated to a decrease in the time of activation of host defense systems after exposure of path-1 colonized plants to virulent pathogens. This was determined by monitoring the biochemical activity of PAL and peroxidase, and the deposition of lignin. It appears that path-1-conferred disease resistance is a multigenic phenomenon which should be more difficult for pathogen to overcome than single gene conferred resistance. Based on the benefits conferred by path-1, we have defined this mutant as expressing a mutualistic lifestyle. REMI (restriction enzyme-mediated integration) nonpathogenic mutants were also isolated using pHA1.3 plasmid linearized with Hind III and transformed into wildtype C. magna. The integrated vector and flanking genomic DNA sequences in REMI mutant R1 was re-isolated and cloned resulting in a product of approximately 11 kb designated pGMR1. Transformations of wildtype C. magna with pGMR1 resulted in the same non-pathogenic phenotype. A nonpathogenic mutant of F.o. melonis (pathogenic to melon) was isolated that colonized melon plants but elicited no disease symptoms in seedlings and conferred 25 - 50% disease protection against the virulent wildtype isolate. Subsequently, nonpathogenic mutant isolates of F.o. niveum (pathogenic to watermelon) were also isolated. Their protection capacity against the respective wildtype parent is currently under investigation. This research has provided information toward a better understanding of host-parasite interactions; specifically, endophytes, pathogens and their hosts. It will also allow us to assess the potential for utilizing nonpathogenic mutants as biological control agents against fungal pathogens and isolating molecular genetic factors of pathogenicity in Fusarium.
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Lichter, Amnon, David Obenland, Nirit Bernstein, Jennifer Hashim et Joseph Smilanick. The role of potassium in quality of grapes after harvest. United States Department of Agriculture, octobre 2015. http://dx.doi.org/10.32747/2015.7597914.bard.
Texte intégralRésumé :
Objectives: The objectives of the proposal were to study how potassium (K) enters the berry and in what tissues it accumulates, to determine what is the sensitive phenological stage that is responsive to K, to study the influence of K on sugar translocation, to determine if K has effects on expression of genes in source and sink organs and to study applied aspects of the responses to K at the vineyard level. During the research it was realized that K acts externally so a major part of the original objectives had to be deserted and new ones, i.e. the role of K in enhancing water loss from the berry, had to be developed. In addition, the US partners developed practical objectives of understanding the interaction of K application and water deficit as well as application of growth regulators. Background: In our preliminary data we showed that application of K at mid-ripening enhanced sugar accumulation of table grapes. This finding is of major implications to both early and late harvested grapes and it was essential to understand the mode of action of this treatment. Our major hypothesis was that K enters the berry and by that increases sugar translocation into the berry. In addition it was important to cover practical issues of the application which may influence its efficacy and its reproducibility. Conclusions: The major conclusion from the research was that our initial hypothesis was wrong. Mineral analysis of pulp tissue indicated that upon application of K there was a significant increase in most of the major minerals. Subsequently, we developed a new hypothesis that K acts by increasing the water loss from the berry. In vitro studies of K-treated berries corroborated this hypothesis showing greater weight-loss of treated berries. This was not necessarily expressed in the vineyard as in some experiments berry weight remained unchanged, suggesting that the vine compensated for the enhanced water loss. Importantly, we also discovered that the efficacy of different K salts was strongly correlated to the pH of the salt solution: basic K salts had better efficacy than neutral or acidic salts and modifying the pH of the same salt changed its efficacy. It was therefore suggested that K changes the properties of the cuticle making it more susceptible to water loss. Of the practical aspects it was found that application of K to the clusters was sufficient to trigger its affect and that dual application of K had a stronger effect than single application. With regard to timing, it was realized that application of K after veraison was affective and the berries responded also when ripe. While the effect of K application was significant at harvest, it was mostly insignificant one week after application, suggesting that prolonged exposure to K was required. Implications: The scientific implications of the study are that the external mineral composition of the berry may have a significant role in sugar accumulation and that water loss may have an important role in sugar accumulation in grapes. It is not entirely clear how K modulates the cuticle but according to the literature its incorporation into the cuticle may increase its polarity and facilitate generation of "water bridges" between the flesh and the environment. The practical implications of this study are very significant because realizing the mode of action of K can facilitate a much more efficient application strategy. For example, it can be understood that sprays must be directed to the clusters rather than the whole vines and it can be predicted that the length of exposure is important. Also, by increasing the pH of simple K salts, the efficacy of the treatment can be enhanced, saving in the costs of the treatment. Finally, the ability of grape growers to apply K in a safe and knowledgeable way can have significant impact on the length of the season of early grape cultivars and improve the flavor of high grape yields which may otherwise have compromised sugar levels.
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Chejanovsky, Nor, Diana Cox-Foster, Victoria Soroker et Ron Ophir. Honeybee modulation of infection with the Israeli acute paralysis virus, in asymptomatic, acutely infected and CCD colonies. United States Department of Agriculture, décembre 2013. http://dx.doi.org/10.32747/2013.7594392.bard.
Texte intégralRésumé :
Honey bee (Apis mellifera) colony losses pose a severe risk to the food chain. The IAPV (Israeli acute paralysis virus) was correlated with CCD, a particular case of colony collapse. Honey bees severely infected with IAPV show shivering wings that progress to paralysis and subsequent death. Bee viruses, including IAPV, are widely present in honey bee colonies but often there are no pathological symptoms. Infestation of the beehive with Varroa mites or exposure to stress factors leads to significant increase in viral titers and fatal infections. We hypothesized that the honey bee is regulating/controlling IAPV and viral infections in asymptomatic infections and this control is broken through "stress" leading to acute infections and/or CCD. Our aims were: 1. To discover genetic changes in IAPV that may affect tissue tropism in the host, and/or virus infectivity and pathogenicity. 2. To elucidate mechanisms used by the host to regulate/ manage the IAPV-infection in vivo and in vitro. To achieve the above objectives we first studied stress-induced virus activation. Our data indicated that some pesticides, including myclobutanil, chlorothalonil and fluvalinate, result in amplified viral titers when bees are exposed at sub lethal levels by a single feeding. Analysis of the level of immune-related bee genes indicated that CCD-colonies exhibit altered and weaker immune responses than healthy colonies. Given the important role of viral RNA interference (RNAi) in combating viral infections we investigated if CCD-colonies were able to elicit this particular antiviral response. Deep-sequencing analysis of samples from CCD-colonies from US and Israel revealed high frequency of small interfering RNAs (siRNA) perfectly matching IAPV, Kashmir bee virus and Deformed wing virus genomes. Israeli colonies showed high titers of IAPV and a conserved RNAi pattern of targeting the viral genome .Our findings were further supported by analysis of samples from colonies experimentally infected with IAPV. Following for the first time the dynamics of IAPV infection in a group of CCD colonies that we rescued from collapse, we found that IAPV conserves its potential to act as one lethal, infectious factor and that its continuous replication in CCD colonies deeply affects their health and survival. Ours is the first report on the dominant role of IAPV in CCD-colonies outside from the US under natural conditions. We concluded that CCD-colonies do exhibit a regular siRNA response that is specific against predominant viruses associated with colony losses and other immune pathways may account for their weak immune response towards virus infection. Our findings: 1. Reveal that preventive measures should be taken by the beekeepers to avoid insecticide-based stress induction of viral infections as well as to manage CCD colonies as a source of highly infectious viruses such as IAPV. 2. Contribute to identify honey bee mechanisms involved in managing viral infections.
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Chefetz, Benny, Baoshan Xing, Leor Eshed-Williams, Tamara Polubesova et Jason Unrine. DOM affected behavior of manufactured nanoparticles in soil-plant system. United States Department of Agriculture, janvier 2016. http://dx.doi.org/10.32747/2016.7604286.bard.
Texte intégralRésumé :
The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.
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Cahaner, Avigdor, Sacit F. Bilgili, Orna Halevy, Roger J. Lien et Kellye S. Joiner. effects of enhanced hypertrophy, reduced oxygen supply and heat load on breast meat yield and quality in broilers. United States Department of Agriculture, novembre 2014. http://dx.doi.org/10.32747/2014.7699855.bard.
Texte intégralRésumé :
Original objectivesThe objectives of this project were to evaluate the growth performance, meat yield and quality attributes of broiler strains widely differing in their genetic potential under normal temperature vs. warm temperature (short and long-term) conditions. Strain differences in breast muscle accretion rate, metabolic responses under heat load and, gross and histopathological changes in breast muscle under thermal load was also to be characterized. BackgroundTremendous genetic progress has been made in broiler chicken growth rate and meat yield since the 1950s. Higher growth rate is driven by higher rates of feed intake and metabolism, resulting in elevated internal heat production. Hot rearing conditions negatively affect broiler growth by hindering dissipation of heat and may lead to a lethal elevation in body temperature. To avoid heat-induced mortality, broilers reduce feed intake, leading to depressed growth rate, lower weight gain, reduce breast meat yield and quality. Thus, the genetic potential of contemporary commercial broilers (CCB) is not fully expressed under hot conditions. Major conclusions, solutions, and achievementsResearch conducted in Israel focused on three broiler strains – CCB, Featherless, Feathered sibs (i.e., sharing similar genetic background). Complimentary research trials conducted at Auburn utilized CCB (Cobb 500, Cobb 700, Ross 308, Ross 708), contrasting their performance to slow growing strains. Warm rearing conditions consistently reduced feed intake, growth rate, feed efficiency, body weight uniformity and breast muscle yield, especially pronounced with CCB and magnified with age. Breast meat quality was also negatively affected, as measured by higher drip loss and paler meat color. Exposure to continuous or short-term heat stress induced respiratory alkalosis. Breast muscle histomorphometrics confirmed enhanced myofiber hypertrophy in CCB. Featherless broilers exhibited a significant increase in blood-vessel density under warm conditions. Rapid growth and muscle accretion rate was correlated to various myopathies (white striping, woody and necrotic) as well as to increases in plasma creatinekinase levels. Whether the trigger(s) of muscle damage is loss of cellular membrane integrity due to oxidative damage or tissue lactate accumulation, or to loss of inter-compartmental cation homeostasis is yet to be determined. Based on genome-wide single-nucleotide polymorphism array genotyping, identification of the gene with the recessive mutation Scaleless (sc) facilitated the development a dCAPS assay to discriminate between sc carrier (sc/+) and non-carrier (+/+) individuals. ImplicationsThis project confirmed that featherless broiler strains grow efficiently with high yield and quality of breast meat, even under warm rearing conditions that significantly depress the overall performance of CCB. Therefore, broiler meat production in hot regions and climates can be substantially improved by introducing the featherless gene into contemporary commercial broiler stocks. This approach has become more feasible with the development of dCAPS assay. A novel modification of the PCR protocol (using whole blood samples instead of extracted DNA) may contribute to the efficient development of commercial featherless broiler strains. Such strains will allow expansion of the broiler meat production in developing countries in warm climates, where energy intensive environmental control of rearing facilities are not economical and easily achievable.