Shipbuilding Docks as Experimental Systems for Realistic Assessments of Anthropogenic Stressors on Marine Organisms

PubMed Central

Harding, Harry R.; Bunce, Tom; Birch, Fiona; Lister, Jessica; Spiga, Ilaria; Benson, Tom; Rossington, Kate; Jones, Diane; Tyler, Charles R.; Simpson, Stephen D.

2017-01-01

Abstract Empirical investigations of the impacts of anthropogenic stressors on marine organisms are typically performed under controlled laboratory conditions, onshore mesocosms, or via offshore experiments with realistic (but uncontrolled) environmental variation. These approaches have merits, but onshore setups are generally small sized and fail to recreate natural stressor fields, whereas offshore studies are often compromised by confounding factors. We suggest the use of flooded shipbuilding docks to allow studying realistic exposure to stressors and their impacts on the intra- and interspecific responses of animals. Shipbuilding docks permit the careful study of groups of known animals, including the evaluation of their behavioral interactions, while enabling full control of the stressor and many environmental conditions. We propose that this approach could be used for assessing the impacts of prominent anthropogenic stressors, including chemicals, ocean warming, and sound. Results from shipbuilding-dock studies could allow improved parameterization of predictive models relating to the environmental risks and population consequences of anthropogenic stressors. PMID:29599545

Shipbuilding Docks as Experimental Systems for Realistic Assessments of Anthropogenic Stressors on Marine Organisms.

PubMed

Bruintjes, Rick; Harding, Harry R; Bunce, Tom; Birch, Fiona; Lister, Jessica; Spiga, Ilaria; Benson, Tom; Rossington, Kate; Jones, Diane; Tyler, Charles R; Radford, Andrew N; Simpson, Stephen D

2017-09-01

Empirical investigations of the impacts of anthropogenic stressors on marine organisms are typically performed under controlled laboratory conditions, onshore mesocosms, or via offshore experiments with realistic (but uncontrolled) environmental variation. These approaches have merits, but onshore setups are generally small sized and fail to recreate natural stressor fields, whereas offshore studies are often compromised by confounding factors. We suggest the use of flooded shipbuilding docks to allow studying realistic exposure to stressors and their impacts on the intra- and interspecific responses of animals. Shipbuilding docks permit the careful study of groups of known animals, including the evaluation of their behavioral interactions, while enabling full control of the stressor and many environmental conditions. We propose that this approach could be used for assessing the impacts of prominent anthropogenic stressors, including chemicals, ocean warming, and sound. Results from shipbuilding-dock studies could allow improved parameterization of predictive models relating to the environmental risks and population consequences of anthropogenic stressors.

[Exposure to addictogenic substances, conditioned response and treatment of the exposure with response prevention].

PubMed

Khazaal, Y; Frésard, E; Zullino, D

2007-01-01

Exposure to drugs or related cues is associated with psycho-physiological reactivity. These responses are conditioned during periods of active consumption. Exposure with response prevention (EPR) is a treatment established for anxiety disorder and aims to reduce anxiety by an extinction of previously conditioned responses. The conditioning recognized in additive processes has led to research into EPR's therapeutic potential for treating addiction. This paper is a review of the main studies on reactivity to cues, and EPR, particularly with respect to addiction to alcohol, opiates, cocaine and tobacco. This review is based on information from the Medline database, dealing with cue reactivity, attentional bias during exposure to cues and exposure treatment for addiction in general and, in particular, for each of the aforementioned substances. Exposure to drug-related cues is clearly associated with psycho-physiological reactivity and with attentional bias. Those phenomena are associated with craving and more difficulty in maintaining abstinence. The subject's attention is thus held by a large number of drug-related environmental stimuli. These observations are linked with conditioning phenomena and suggest the possibility of treatment by EPR conditioning extinction procedures. EPR has been most widely studied for abuse and alcohol addiction. Case reports give favourable outcomes. Results from controlled studies are less clear. Studies on patients addicted to cocaine or heroine are still limited and not conclusive. Different controlled studies on EPR for nicotine addiction have not produced conclusions in favour of this treatment. Generally, the EPR procedures used vary among studies. Studies focussing particularly on the evolution of physiological responses in a laboratory setting after EPR have demonstrated reduced autonomic nervous system activity. These results do not consistently lead to a reduction in consumption behaviour and in craving when the patient is in

Modelling effects of diquat under realistic exposure patterns in genetically differentiated populations of the gastropod Lymnaea stagnalis

PubMed Central

Ducrot, Virginie; Péry, Alexandre R. R.; Lagadic, Laurent

2010-01-01

Pesticide use leads to complex exposure and response patterns in non-target aquatic species, so that the analysis of data from standard toxicity tests may result in unrealistic risk forecasts. Developing models that are able to capture such complexity from toxicity test data is thus a crucial issue for pesticide risk assessment. In this study, freshwater snails from two genetically differentiated populations of Lymnaea stagnalis were exposed to repeated acute applications of environmentally realistic concentrations of the herbicide diquat, from the embryo to the adult stage. Hatching rate, embryonic development duration, juvenile mortality, feeding rate and age at first spawning were investigated during both exposure and recovery periods. Effects of diquat on mortality were analysed using a threshold hazard model accounting for time-varying herbicide concentrations. All endpoints were significantly impaired at diquat environmental concentrations in both populations. Snail evolutionary history had no significant impact on their sensitivity and responsiveness to diquat, whereas food acted as a modulating factor of toxicant-induced mortality. The time course of effects was adequately described by the model, which thus appears suitable to analyse long-term effects of complex exposure patterns based upon full life cycle experiment data. Obtained model outputs (e.g. no-effect concentrations) could be directly used for chemical risk assessment. PMID:20921047

Modelling effects of diquat under realistic exposure patterns in genetically differentiated populations of the gastropod Lymnaea stagnalis.

PubMed

Ducrot, Virginie; Péry, Alexandre R R; Lagadic, Laurent

2010-11-12

Pesticide use leads to complex exposure and response patterns in non-target aquatic species, so that the analysis of data from standard toxicity tests may result in unrealistic risk forecasts. Developing models that are able to capture such complexity from toxicity test data is thus a crucial issue for pesticide risk assessment. In this study, freshwater snails from two genetically differentiated populations of Lymnaea stagnalis were exposed to repeated acute applications of environmentally realistic concentrations of the herbicide diquat, from the embryo to the adult stage. Hatching rate, embryonic development duration, juvenile mortality, feeding rate and age at first spawning were investigated during both exposure and recovery periods. Effects of diquat on mortality were analysed using a threshold hazard model accounting for time-varying herbicide concentrations. All endpoints were significantly impaired at diquat environmental concentrations in both populations. Snail evolutionary history had no significant impact on their sensitivity and responsiveness to diquat, whereas food acted as a modulating factor of toxicant-induced mortality. The time course of effects was adequately described by the model, which thus appears suitable to analyse long-term effects of complex exposure patterns based upon full life cycle experiment data. Obtained model outputs (e.g. no-effect concentrations) could be directly used for chemical risk assessment.

The multi-modal responses of a physical head model subjected to various blast exposure conditions

NASA Astrophysics Data System (ADS)

Ouellet, S.; Philippens, M.

2018-01-01

structure, and direction of propagation. Convincing evidence of stresses generated from local skull deformation is presented along with evidence of stress transmission through relative brain-to-skull motion. These findings suggest that research aimed at defining exposure thresholds should not focus on a single stress transmission mechanism or use experimental designs unrepresentative of realistic blast loading conditions that may favour a given mechanism over another.

The Formation of Teacher Work Teams under Adverse Conditions: Towards a More Realistic Scenario for Schools in Distress

ERIC Educational Resources Information Center

Mintrop, Rick; Charles, Jessica

2017-01-01

Group formation studies are rare in the literature on teacher professional learning communities (PLCs). But they are needed to render realistic scenarios and design interventions for practitioners who work in schools where teachers encounter distress and social adversity. Under these conditions, we may need approaches to PLC development that are…

Evaluation of air-liquid interface exposure systems for in vitro assessment of airborne pollutants

EPA Science Inventory

Exposure of cells to airborne pollutants at the air-liquid interface (ALI) is a more realistic approach than exposures of submerged cells. The published literature, however, describes irreproducible and/or unrealistic experimental conditions using ALI systems. We have compared fi...

Is realistic neuronal modeling realistic?

PubMed Central

Almog, Mara

2016-01-01

Scientific models are abstractions that aim to explain natural phenomena. A successful model shows how a complex phenomenon arises from relatively simple principles while preserving major physical or biological rules and predicting novel experiments. A model should not be a facsimile of reality; it is an aid for understanding it. Contrary to this basic premise, with the 21st century has come a surge in computational efforts to model biological processes in great detail. Here we discuss the oxymoronic, realistic modeling of single neurons. This rapidly advancing field is driven by the discovery that some neurons don't merely sum their inputs and fire if the sum exceeds some threshold. Thus researchers have asked what are the computational abilities of single neurons and attempted to give answers using realistic models. We briefly review the state of the art of compartmental modeling highlighting recent progress and intrinsic flaws. We then attempt to address two fundamental questions. Practically, can we realistically model single neurons? Philosophically, should we realistically model single neurons? We use layer 5 neocortical pyramidal neurons as a test case to examine these issues. We subject three publically available models of layer 5 pyramidal neurons to three simple computational challenges. Based on their performance and a partial survey of published models, we conclude that current compartmental models are ad hoc, unrealistic models functioning poorly once they are stretched beyond the specific problems for which they were designed. We then attempt to plot possible paths for generating realistic single neuron models. PMID:27535372

Low cost digester monitoring under realistic conditions: Rural use of biogas and digestate quality.

PubMed

Castro, L; Escalante, H; Jaimes-Estévez, J; Díaz, L J; Vecino, K; Rojas, G; Mantilla, L

2017-09-01

The purpose of this work was to assess the behaviour of anaerobic digestion of cattle manure in a rural digester under realistic conditions, and estimate the quality and properties of the digestate. The data obtained during monitoring indicated that the digester operation was stable without risk of inhibition. It produced an average of 0.85Nm 3 biogas/d at 65.6% methane, providing an energy savings of 76%. In addition, the digestate contained high nutrient concentrations, which is an important feature of fertilizers. However, this method requires post-treatment due to the presence of pathogens. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optical filter highlighting spectral features part II: quantitative measurements of cosmetic foundation and assessment of their spatial distributions under realistic facial conditions.

PubMed

Nishino, Ken; Nakamura, Mutsuko; Matsumoto, Masayuki; Tanno, Osamu; Nakauchi, Shigeki

2011-03-28

We previously proposed a filter that could detect cosmetic foundations with high discrimination accuracy [Opt. Express 19, 6020 (2011)]. This study extends the filter's functionality to the quantification of the amount of foundation and applies the filter for the assessment of spatial distributions of foundation under realistic facial conditions. Human faces that are applied with quantitatively controlled amounts of cosmetic foundations were measured using the filter. A calibration curve between pixel values of the image and the amount of foundation was created. The optical filter was applied to visualize spatial foundation distributions under realistic facial conditions, which clearly indicated areas on the face where foundation remained even after cleansing. Results confirm that the proposed filter could visualize and nondestructively inspect the foundation distributions.

Particulate matter from both heavy fuel oil and diesel fuel shipping emissions show strong biological effects on human lung cells at realistic and comparable in vitro exposure conditions.

PubMed

Oeder, Sebastian; Kanashova, Tamara; Sippula, Olli; Sapcariu, Sean C; Streibel, Thorsten; Arteaga-Salas, Jose Manuel; Passig, Johannes; Dilger, Marco; Paur, Hanns-Rudolf; Schlager, Christoph; Mülhopt, Sonja; Diabaté, Silvia; Weiss, Carsten; Stengel, Benjamin; Rabe, Rom; Harndorf, Horst; Torvela, Tiina; Jokiniemi, Jorma K; Hirvonen, Maija-Riitta; Schmidt-Weber, Carsten; Traidl-Hoffmann, Claudia; BéruBé, Kelly A; Wlodarczyk, Anna J; Prytherch, Zoë; Michalke, Bernhard; Krebs, Tobias; Prévôt, André S H; Kelbg, Michael; Tiggesbäumker, Josef; Karg, Erwin; Jakobi, Gert; Scholtes, Sorana; Schnelle-Kreis, Jürgen; Lintelmann, Jutta; Matuschek, Georg; Sklorz, Martin; Klingbeil, Sophie; Orasche, Jürgen; Richthammer, Patrick; Müller, Laarnie; Elsasser, Michael; Reda, Ahmed; Gröger, Thomas; Weggler, Benedikt; Schwemer, Theo; Czech, Hendryk; Rüger, Christopher P; Abbaszade, Gülcin; Radischat, Christian; Hiller, Karsten; Buters, Jeroen T M; Dittmar, Gunnar; Zimmermann, Ralf

2015-01-01

Ship engine emissions are important with regard to lung and cardiovascular diseases especially in coastal regions worldwide. Known cellular responses to combustion particles include oxidative stress and inflammatory signalling. To provide a molecular link between the chemical and physical characteristics of ship emission particles and the cellular responses they elicit and to identify potentially harmful fractions in shipping emission aerosols. Through an air-liquid interface exposure system, we exposed human lung cells under realistic in vitro conditions to exhaust fumes from a ship engine running on either common heavy fuel oil (HFO) or cleaner-burning diesel fuel (DF). Advanced chemical analyses of the exhaust aerosols were combined with transcriptional, proteomic and metabolomic profiling including isotope labelling methods to characterise the lung cell responses. The HFO emissions contained high concentrations of toxic compounds such as metals and polycyclic aromatic hydrocarbon, and were higher in particle mass. These compounds were lower in DF emissions, which in turn had higher concentrations of elemental carbon ("soot"). Common cellular reactions included cellular stress responses and endocytosis. Reactions to HFO emissions were dominated by oxidative stress and inflammatory responses, whereas DF emissions induced generally a broader biological response than HFO emissions and affected essential cellular pathways such as energy metabolism, protein synthesis, and chromatin modification. Despite a lower content of known toxic compounds, combustion particles from the clean shipping fuel DF influenced several essential pathways of lung cell metabolism more strongly than particles from the unrefined fuel HFO. This might be attributable to a higher soot content in DF. Thus the role of diesel soot, which is a known carcinogen in acute air pollution-induced health effects should be further investigated. For the use of HFO and DF we recommend a reduction of

Particulate Matter from Both Heavy Fuel Oil and Diesel Fuel Shipping Emissions Show Strong Biological Effects on Human Lung Cells at Realistic and Comparable In Vitro Exposure Conditions

PubMed Central

Dilger, Marco; Paur, Hanns-Rudolf; Schlager, Christoph; Mülhopt, Sonja; Diabaté, Silvia; Weiss, Carsten; Stengel, Benjamin; Rabe, Rom; Harndorf, Horst; Torvela, Tiina; Jokiniemi, Jorma K.; Hirvonen, Maija-Riitta; Schmidt-Weber, Carsten; Traidl-Hoffmann, Claudia; BéruBé, Kelly A.; Wlodarczyk, Anna J.; Prytherch, Zoë; Michalke, Bernhard; Krebs, Tobias; Prévôt, André S. H.; Kelbg, Michael; Tiggesbäumker, Josef; Karg, Erwin; Jakobi, Gert; Scholtes, Sorana; Schnelle-Kreis, Jürgen; Lintelmann, Jutta; Matuschek, Georg; Sklorz, Martin; Klingbeil, Sophie; Orasche, Jürgen; Richthammer, Patrick; Müller, Laarnie; Elsasser, Michael; Reda, Ahmed; Gröger, Thomas; Weggler, Benedikt; Schwemer, Theo; Czech, Hendryk; Rüger, Christopher P.; Abbaszade, Gülcin; Radischat, Christian; Hiller, Karsten; Buters, Jeroen T. M.; Dittmar, Gunnar; Zimmermann, Ralf

2015-01-01

Background Ship engine emissions are important with regard to lung and cardiovascular diseases especially in coastal regions worldwide. Known cellular responses to combustion particles include oxidative stress and inflammatory signalling. Objectives To provide a molecular link between the chemical and physical characteristics of ship emission particles and the cellular responses they elicit and to identify potentially harmful fractions in shipping emission aerosols. Methods Through an air-liquid interface exposure system, we exposed human lung cells under realistic in vitro conditions to exhaust fumes from a ship engine running on either common heavy fuel oil (HFO) or cleaner-burning diesel fuel (DF). Advanced chemical analyses of the exhaust aerosols were combined with transcriptional, proteomic and metabolomic profiling including isotope labelling methods to characterise the lung cell responses. Results The HFO emissions contained high concentrations of toxic compounds such as metals and polycyclic aromatic hydrocarbon, and were higher in particle mass. These compounds were lower in DF emissions, which in turn had higher concentrations of elemental carbon (“soot”). Common cellular reactions included cellular stress responses and endocytosis. Reactions to HFO emissions were dominated by oxidative stress and inflammatory responses, whereas DF emissions induced generally a broader biological response than HFO emissions and affected essential cellular pathways such as energy metabolism, protein synthesis, and chromatin modification. Conclusions Despite a lower content of known toxic compounds, combustion particles from the clean shipping fuel DF influenced several essential pathways of lung cell metabolism more strongly than particles from the unrefined fuel HFO. This might be attributable to a higher soot content in DF. Thus the role of diesel soot, which is a known carcinogen in acute air pollution-induced health effects should be further investigated. For the

The Toxicological Evaluation of Realistic Emissions of Source Aerosols Study: Statistical Methods

PubMed Central

Coull, Brent A.; Wellenius, Gregory A.; Gonzalez-Flecha, Beatriz; Diaz, Edgar; Koutrakis, Petros; Godleski, John J.

2013-01-01

The Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) study involved withdrawal, aging, and atmospheric transformation of emissions of three coal-fired power plants. Toxicological evaluations were carried out in rats exposed to different emission scenarios with extensive exposure characterization. Data generated had multiple levels of resolution: exposure, scenario and constituent chemical composition. Here, we outline a multilayered approach to analyze the associations between exposure and health effects beginning with standard ANOVA models that treat exposure as a categorical variable. The model assessed differences in exposure effects across scenarios (by plant). To assess unadjusted associations between pollutant concentrations and health, univariate analyses were conducted using the difference between the response means under exposed and control conditions and a single constituent concentration as the predictor. Then, a novel multivariate analysis of exposure composition and health was used based on random forests, a recent extension of classification and regression trees that were applied to the outcome differences. For each exposure constituent, this approach yielded a nonparametric measure of the importance of that constituent in predicting differences in response on a given day, controlling for the other measured constituent concentrations in the model. Finally, an R2 analysis compared the relative importance of exposure scenario, plant, and constituent concentrations on each outcome. Peak expiratory flow is used to demonstrate how the multiple levels of the analysis complement each other to assess constituents most strongly associated with health effects. PMID:21913820

The toxicological evaluation of realistic emissions of source aerosols study: statistical methods.

PubMed

Coull, Brent A; Wellenius, Gregory A; Gonzalez-Flecha, Beatriz; Diaz, Edgar; Koutrakis, Petros; Godleski, John J

2011-08-01

The Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) study involved withdrawal, aging, and atmospheric transformation of emissions of three coal-fired power plants. Toxicological evaluations were carried out in rats exposed to different emission scenarios with extensive exposure characterization. Data generated had multiple levels of resolution: exposure, scenario, and constituent chemical composition. Here, we outline a multilayered approach to analyze the associations between exposure and health effects beginning with standard ANOVA models that treat exposure as a categorical variable. The model assessed differences in exposure effects across scenarios (by plant). To assess unadjusted associations between pollutant concentrations and health, univariate analyses were conducted using the difference between the response means under exposed and control conditions and a single constituent concentration as the predictor. Then, a novel multivariate analysis of exposure composition and health was used based on Random Forests(™), a recent extension of classification and regression trees that were applied to the outcome differences. For each exposure constituent, this approach yielded a nonparametric measure of the importance of that constituent in predicting differences in response on a given day, controlling for the other measured constituent concentrations in the model. Finally, an R(2) analysis compared the relative importance of exposure scenario, plant, and constituent concentrations on each outcome. Peak expiratory flow (PEF) is used to demonstrate how the multiple levels of the analysis complement each other to assess constituents most strongly associated with health effects.

Synchronized moving aperture radiation therapy (SMART): superimposing tumor motion on IMRT MLC leaf sequences under realistic delivery conditions

NASA Astrophysics Data System (ADS)

Xu, Jun; Papanikolaou, Nikos; Shi, Chengyu; Jiang, Steve B.

2009-08-01

Synchronized moving aperture radiation therapy (SMART) has been proposed to account for tumor motions during radiotherapy in prior work. The basic idea of SMART is to synchronize the moving radiation beam aperture formed by a dynamic multileaf collimator (DMLC) with the tumor motion induced by respiration. In this paper, a two-dimensional (2D) superimposing leaf sequencing method is presented for SMART. A leaf sequence optimization strategy was generated to assure the SMART delivery under realistic delivery conditions. The study of delivery performance using the Varian LINAC and the Millennium DMLC showed that clinical factors such as collimator angle, dose rate, initial phase and machine tolerance affect the delivery accuracy and efficiency. An in-house leaf sequencing software was developed to implement the 2D superimposing leaf sequencing method and optimize the motion-corrected leaf sequence under realistic clinical conditions. The analysis of dynamic log (Dynalog) files showed that optimization of the leaf sequence for various clinical factors can avoid beam hold-offs which break the synchronization of SMART and fail the SMART dose delivery. Through comparison between the simulated delivered fluence map and the planed fluence map, it was shown that the motion-corrected leaf sequence can greatly reduce the dose error.

Synchronized moving aperture radiation therapy (SMART): superimposing tumor motion on IMRT MLC leaf sequences under realistic delivery conditions.

PubMed

Xu, Jun; Papanikolaou, Nikos; Shi, Chengyu; Jiang, Steve B

2009-08-21

Synchronized moving aperture radiation therapy (SMART) has been proposed to account for tumor motions during radiotherapy in prior work. The basic idea of SMART is to synchronize the moving radiation beam aperture formed by a dynamic multileaf collimator (DMLC) with the tumor motion induced by respiration. In this paper, a two-dimensional (2D) superimposing leaf sequencing method is presented for SMART. A leaf sequence optimization strategy was generated to assure the SMART delivery under realistic delivery conditions. The study of delivery performance using the Varian LINAC and the Millennium DMLC showed that clinical factors such as collimator angle, dose rate, initial phase and machine tolerance affect the delivery accuracy and efficiency. An in-house leaf sequencing software was developed to implement the 2D superimposing leaf sequencing method and optimize the motion-corrected leaf sequence under realistic clinical conditions. The analysis of dynamic log (Dynalog) files showed that optimization of the leaf sequence for various clinical factors can avoid beam hold-offs which break the synchronization of SMART and fail the SMART dose delivery. Through comparison between the simulated delivered fluence map and the planed fluence map, it was shown that the motion-corrected leaf sequence can greatly reduce the dose error.

The Effect of Microplastic on the Uptake of Chemicals by the Lugworm Arenicola marina (L.) under Environmentally Relevant Exposure Conditions

PubMed Central

2017-01-01

It has been hypothesized that ingestion of microplastic increases exposure of aquatic organisms to hydrophobic contaminants. To date, most laboratory studies investigated chemical transfer from ingested microplastic without taking other exposure pathways into account. Therefore, we studied the effect of polyethylene (PE) microplastic in sediment on PCB uptake by Arenicola marina as a model species, quantifying uptake fluxes from all natural exposure pathways. PCB concentrations in sediment, biota lipids (Clip) and porewater measured with passive samplers were used to derive lipid-normalized bioaccumulation metrics Clip, Biota sediment accumulation factor (BSAF), Bioaccumulation factor (BAF) and the Biota plastic accumulation factor (BPAF). Small effects of PE addition were detected suggesting slightly increased or decreased bioaccumulation. However, the differences decreased in magnitude dependent on the metric used to assess bioaccumulation, in the order: Clip > BSAF > BPAF > BAF, and were nonsignificant for BAF. The fact that BAF, that is, normalization of Clip on porewater concentration, largely removed all effects of PE, shows that PE did not act as a measurable vector of PCBs. Biodynamic model analysis confirmed that PE ingestion contributed marginally to bioaccumulation. This work confirmed model-based predictions on the limited relevance of microplastic for bioaccumulation under environmentally realistic conditions, and illustrated the importance of assessing exposure through all media in microplastic bioaccumulation studies. PMID:28682597

Controlling Item Exposure Conditional on Ability in Computerized Adaptive Testing.

ERIC Educational Resources Information Center

Stocking, Martha L.; Lewis, Charles

1998-01-01

Ensuring item and pool security in a continuous testing environment is explored through a new method of controlling exposure rate of items conditional on ability level in computerized testing. Properties of this conditional control on exposure rate, when used in conjunction with a particular adaptive testing algorithm, are explored using simulated…

Does therapeutic writing help people with long-term conditions? Systematic review, realist synthesis and economic considerations.

PubMed

Nyssen, Olga P; Taylor, Stephanie J C; Wong, Geoff; Steed, Elizabeth; Bourke, Liam; Lord, Joanne; Ross, Carol A; Hayman, Sheila; Field, Victoria; Higgins, Ailish; Greenhalgh, Trisha; Meads, Catherine

2016-04-01

Writing therapy to improve physical or mental health can take many forms. The most researched model of therapeutic writing (TW) is unfacilitated, individual expressive writing (written emotional disclosure). Facilitated writing activities are less widely researched. Databases, including MEDLINE, EMBASE, PsycINFO, Linguistics and Language Behaviour Abstracts, Allied and Complementary Medicine Database and Cumulative Index to Nursing and Allied Health Literature, were searched from inception to March 2013 (updated January 2015). Four TW practitioners provided expert advice. Study procedures were conducted by one reviewer and checked by a second. Randomised controlled trials (RCTs) and non-randomised comparative studies were included. Quality was appraised using the Cochrane risk-of-bias tool. Unfacilitated and facilitated TW studies were analysed separately under International Classification of Diseases, Tenth Revision chapter headings. Meta-analyses were performed where possible using RevMan version 5.2.6 (RevMan 2012, The Cochrane Collaboration, The Nordic Cochrane Centre, Copenhagen, Denmark). Costs were estimated from a UK NHS perspective and three cost-consequence case studies were prepared. Realist synthesis followed Realist and Meta-narrative Evidence Synthesis: Evolving Standards guidelines. To review the clinical effectiveness and cost-effectiveness of TW for people with long-term conditions (LTCs) compared with no writing, or other controls, reporting any relevant clinical outcomes. To conduct a realist synthesis to understand how TW might work, and for whom. From 14,658 unique citations, 284 full-text papers were reviewed and 64 studies (59 RCTs) were included in the final effectiveness reviews. Five studies examined facilitated TW; these were extremely heterogeneous with unclear or high risk of bias but suggested that facilitated TW interventions may be beneficial in individual LTCs. Unfacilitated expressive writing was examined in 59 studies of variable

Realist complex intervention science: Applying realist principles across all phases of the Medical Research Council framework for developing and evaluating complex interventions

PubMed Central

Fletcher, Adam; Jamal, Farah; Moore, Graham; Evans, Rhiannon E.; Murphy, Simon; Bonell, Chris

2016-01-01

The integration of realist evaluation principles within randomised controlled trials (‘realist RCTs’) enables evaluations of complex interventions to answer questions about what works, for whom and under what circumstances. This allows evaluators to better develop and refine mid-level programme theories. However, this is only one phase in the process of developing and evaluating complex interventions. We describe and exemplify how social scientists can integrate realist principles across all phases of the Medical Research Council framework. Intervention development, modelling, and feasibility and pilot studies need to theorise the contextual conditions necessary for intervention mechanisms to be activated. Where interventions are scaled up and translated into routine practice, realist principles also have much to offer in facilitating knowledge about longer-term sustainability, benefits and harms. Integrating a realist approach across all phases of complex intervention science is vital for considering the feasibility and likely effects of interventions for different localities and population subgroups. PMID:27478401

Quantum-continuum simulation of the electrochemical response of pseudocapacitor electrodes under realistic conditions

NASA Astrophysics Data System (ADS)

Keilbart, Nathan; Okada, Yasuaki; Feehan, Aion; Higai, Shin'ichi; Dabo, Ismaila

2017-03-01

Pseudocapacitors are energy-storage devices characterized by fast and reversible redox reactions that enable them to store large amounts of electrical energy at high rates. We simulate the response of pseudocapacitive electrodes under realistic conditions to identify the microscopic factors that determine their performance, focusing on ruthenia (RuO2) as a prototypical electrode material. Electronic-structure methods are used together with a self-consistent continuum solvation (SCCS) model to build a complete data set of free energies as the surface of the charged electrode is gradually covered with protons under applied voltage. The resulting data set is exploited to compute hydrogen-adsorption isotherms and charge-voltage responses by means of grand-canonical sampling, finding close agreement with experimental voltammetry. These simulations reveal that small changes on the order of 5 μ F /cm2 in the intrinsic double-layer capacitance of the electrode-electrolyte interface can induce variations of up to 40 μ F /cm2 in the overall pseudocapacitance.

Prior cocaine exposure disrupts extinction of fear conditioning

PubMed Central

Burke, Kathryn A.; Franz, Theresa M.; Gugsa, Nishan; Schoenbaum, Geoffrey

2008-01-01

Psychostimulant exposure has been shown to cause molecular and cellular changes in prefrontal cortex. It has been hypothesized that these drug-induced changes might affect the operation of prefrontal-limbic circuits, disrupting their normal role in controlling behavior and thereby leading to compulsive drug-seeking. To test this hypothesis, we tested cocaine-treated rats in a fear conditioning, inflation, and extinction task, known to depend on medial prefrontal cortex and amygdala. Cocaine-treated rats conditioned and inflated similar to saline controls but displayed slower extinction learning. These results support the hypothesis that control processes in the medial prefrontal cortex are impaired by cocaine exposure. PMID:16847305

Prior cocaine exposure disrupts extinction of fear conditioning.

PubMed

Burke, Kathryn A; Franz, Theresa M; Gugsa, Nishan; Schoenbaum, Geoffrey

2006-01-01

Psychostimulant exposure has been shown to cause molecular and cellular changes in prefrontal cortex. It has been hypothesized that these drug-induced changes might affect the operation of prefrontal-limbic circuits, disrupting their normal role in controlling behavior and thereby leading to compulsive drug-seeking. To test this hypothesis, we tested cocaine-treated rats in a fear conditioning, inflation, and extinction task, known to depend on medial prefrontal cortex and amygdala. Cocaine-treated rats conditioned and inflated similar to saline controls but displayed slower extinction learning. These results support the hypothesis that control processes in the medial prefrontal cortex are impaired by cocaine exposure.

Exposure of Mammalian Cells to Air-Pollutant Mixtures at the Air-Liquid Interface

EPA Science Inventory

It has been widely accepted that exposure of mammalian cells to air-pollutant mixtures at the air-liquid interface is a more realistic approach than exposing cell under submerged conditions. The VITROCELL systems, are commercially available systems for air-liquid interface expo...

Do absorption and realistic distraction influence performance of component task surgical procedure?

PubMed

Pluyter, Jon R; Buzink, Sonja N; Rutkowski, Anne-F; Jakimowicz, Jack J

2010-04-01

Surgeons perform complex tasks while exposed to multiple distracting sources that may increase stress in the operating room (e.g., music, conversation, and unadapted use of sophisticated technologies). This study aimed to examine whether such realistic social and technological distracting conditions may influence surgical performance. Twelve medical interns performed a laparoscopic cholecystectomy task with the Xitact LC 3.0 virtual reality simulator under distracting conditions (exposure to music, conversation, and nonoptimal handling of the laparoscope) versus nondistracting conditions (control condition) as part of a 2 x 2 within-subject experimental design. Under distracting conditions, the medical interns showed a significant decline in task performance (overall task score, task errors, and operating time) and significantly increased levels of irritation toward both the assistant handling the laparoscope in a nonoptimal way and the sources of social distraction. Furthermore, individual differences in cognitive style (i.e., cognitive absorption and need for cognition) significantly influenced the levels of irritation experienced by the medical interns. The results suggest careful evaluation of the social and technological sources of distraction in the operation room to reduce irritation for the surgeon and provision of proper preclinical laparoscope navigation training to increase security for the patient.

Order Matters: Sequencing Scale-Realistic Versus Simplified Models to Improve Science Learning

NASA Astrophysics Data System (ADS)

Chen, Chen; Schneps, Matthew H.; Sonnert, Gerhard

2016-10-01

Teachers choosing between different models to facilitate students' understanding of an abstract system must decide whether to adopt a model that is simplified and striking or one that is realistic and complex. Only recently have instructional technologies enabled teachers and learners to change presentations swiftly and to provide for learning based on multiple models, thus giving rise to questions about the order of presentation. Using disjoint individual growth modeling to examine the learning of astronomical concepts using a simulation of the solar system on tablets for 152 high school students (age 15), the authors detect both a model effect and an order effect in the use of the Orrery, a simplified model that exaggerates the scale relationships, and the True-to-scale, a proportional model that more accurately represents the realistic scale relationships. Specifically, earlier exposure to the simplified model resulted in diminution of the conceptual gain from the subsequent realistic model, but the realistic model did not impede learning from the following simplified model.

The Effect of Microplastic on the Uptake of Chemicals by the Lugworm Arenicola marina (L.) under Environmentally Relevant Exposure Conditions.

PubMed

Besseling, Ellen; Foekema, Edwin M; van den Heuvel-Greve, Martine J; Koelmans, Albert A

2017-08-01

It has been hypothesized that ingestion of microplastic increases exposure of aquatic organisms to hydrophobic contaminants. To date, most laboratory studies investigated chemical transfer from ingested microplastic without taking other exposure pathways into account. Therefore, we studied the effect of polyethylene (PE) microplastic in sediment on PCB uptake by Arenicola marina as a model species, quantifying uptake fluxes from all natural exposure pathways. PCB concentrations in sediment, biota lipids (C lip ) and porewater measured with passive samplers were used to derive lipid-normalized bioaccumulation metrics C lip , Biota sediment accumulation factor (BSAF), Bioaccumulation factor (BAF) and the Biota plastic accumulation factor (BPAF). Small effects of PE addition were detected suggesting slightly increased or decreased bioaccumulation. However, the differences decreased in magnitude dependent on the metric used to assess bioaccumulation, in the order: C lip > BSAF > BPAF > BAF, and were nonsignificant for BAF. The fact that BAF, that is, normalization of C lip on porewater concentration, largely removed all effects of PE, shows that PE did not act as a measurable vector of PCBs. Biodynamic model analysis confirmed that PE ingestion contributed marginally to bioaccumulation. This work confirmed model-based predictions on the limited relevance of microplastic for bioaccumulation under environmentally realistic conditions, and illustrated the importance of assessing exposure through all media in microplastic bioaccumulation studies.

Adolescent nicotine exposure disrupts context conditioning in adulthood in rats.

PubMed

Spaeth, Andrea M; Barnet, Robert C; Hunt, Pamela S; Burk, Joshua A

2010-10-01

Despite the prevalence of smoking among adolescents, few studies have assessed the effects of adolescent nicotine exposure on learning in adulthood. In particular, it remains unclear whether adolescent nicotine exposure has effects on hippocampus-dependent learning that persist into adulthood. The present experiment examined whether there were effects of adolescent nicotine exposure on context conditioning, a form of learning dependent on the integrity of the hippocampus, when tested during adulthood. Rats were exposed to nicotine during adolescence (postnatal days [PD] 28-42) via osmotic minipump (0, 3.0 or 6.0mg/kg/day). Context conditioning occurred in early adulthood (PD 65-70). Animals were exposed to an experimental context and were given 10 unsignaled footshocks or no shock. Additional groups were included to test the effects of adolescent nicotine on delay conditioning, a form of learning that is not dependent upon the hippocampus. Conditioning was assessed using a lick suppression paradigm. For animals in the context conditioning groups, adolescent nicotine resulted in significantly less suppression of drinking in the presence of context cues compared with vehicle-pretreated animals. For animals in the delay conditioning groups, there was a trend for adolescent nicotine (3.0mg/kg/day) to suppress drinking compared to vehicle-pretreated animals. There were no differences in extinction of contextual fear or cued fear between rats previously exposed to vehicle or nicotine. The data indicate that adolescent nicotine administration impairs context conditioning when animals are trained and tested as adults. The present data suggest that adolescent nicotine exposure may disrupt hippocampus-dependent learning when animals are tested during adulthood. (c) 2010 Elsevier Inc. All rights reserved.

Maltreatment Exposure, Brain Structure, and Fear Conditioning in Children and Adolescents.

PubMed

McLaughlin, Katie A; Sheridan, Margaret A; Gold, Andrea L; Duys, Andrea; Lambert, Hilary K; Peverill, Matthew; Heleniak, Charlotte; Shechner, Tomer; Wojcieszak, Zuzanna; Pine, Daniel S

2016-07-01

Alterations in learning processes and the neural circuitry that supports fear conditioning and extinction represent mechanisms through which trauma exposure might influence risk for psychopathology. Few studies examine how trauma or neural structure relates to fear conditioning in children. Children (n=94) aged 6-18 years, 40.4% (n=38) with exposure to maltreatment (physical abuse, sexual abuse, or domestic violence), completed a fear conditioning paradigm utilizing blue and yellow bells as conditioned stimuli (CS+/CS-) and an aversive alarm noise as the unconditioned stimulus. Skin conductance responses (SCR) and self-reported fear were acquired. Magnetic resonance imaging data were acquired from 60 children. Children without maltreatment exposure exhibited strong differential conditioning to the CS+ vs CS-, based on SCR and self-reported fear. In contrast, maltreated children exhibited blunted SCR to the CS+ and failed to exhibit differential SCR to the CS+ vs CS- during early conditioning. Amygdala and hippocampal volume were reduced among children with maltreatment exposure and were negatively associated with SCR to the CS+ during early conditioning in the total sample, although these associations were negative only among non-maltreated children and were positive among maltreated children. The association of maltreatment with externalizing psychopathology was mediated by this perturbed pattern of fear conditioning. Child maltreatment is associated with failure to discriminate between threat and safety cues during fear conditioning in children. Poor threat-safety discrimination might reflect either enhanced fear generalization or a deficit in associative learning, which may in turn represent a central mechanism underlying the development of maltreatment-related externalizing psychopathology in children.

Maltreatment Exposure, Brain Structure, and Fear Conditioning in Children and Adolescents

PubMed Central

McLaughlin, Katie A; Sheridan, Margaret A; Gold, Andrea L; Duys, Andrea; Lambert, Hilary K; Peverill, Matthew; Heleniak, Charlotte; Shechner, Tomer; Wojcieszak, Zuzanna; Pine, Daniel S

2016-01-01

Alterations in learning processes and the neural circuitry that supports fear conditioning and extinction represent mechanisms through which trauma exposure might influence risk for psychopathology. Few studies examine how trauma or neural structure relates to fear conditioning in children. Children (n=94) aged 6–18 years, 40.4% (n=38) with exposure to maltreatment (physical abuse, sexual abuse, or domestic violence), completed a fear conditioning paradigm utilizing blue and yellow bells as conditioned stimuli (CS+/CS−) and an aversive alarm noise as the unconditioned stimulus. Skin conductance responses (SCR) and self-reported fear were acquired. Magnetic resonance imaging data were acquired from 60 children. Children without maltreatment exposure exhibited strong differential conditioning to the CS+ vs CS−, based on SCR and self-reported fear. In contrast, maltreated children exhibited blunted SCR to the CS+ and failed to exhibit differential SCR to the CS+ vs CS− during early conditioning. Amygdala and hippocampal volume were reduced among children with maltreatment exposure and were negatively associated with SCR to the CS+ during early conditioning in the total sample, although these associations were negative only among non-maltreated children and were positive among maltreated children. The association of maltreatment with externalizing psychopathology was mediated by this perturbed pattern of fear conditioning. Child maltreatment is associated with failure to discriminate between threat and safety cues during fear conditioning in children. Poor threat–safety discrimination might reflect either enhanced fear generalization or a deficit in associative learning, which may in turn represent a central mechanism underlying the development of maltreatment-related externalizing psychopathology in children. PMID:26677946

Pre-exposure to wheel running disrupts taste aversion conditioning.

PubMed

Salvy, Sarah-Jeanne; Pierce, W David; Heth, Donald C; Russell, James C

2002-05-01

When rats are given access to a running wheel after drinking a flavored solution, they subsequently drink less of that flavor solution. It has been suggested that running produces a conditioned taste aversion (CTA). This study explored whether CTA is eliminated by prior exposure to wheel running [i.e., unconditioned stimulus (UCS) pre-exposure effect]. The rats in the experimental group (UW) were allowed to wheel run for 1 h daily for seven consecutive days of pre-exposure. Rats in the two other groups had either access to locked wheels (LW group) or were maintained in their home cages (HC group) during the pre-exposure days. All rats were then exposed to four paired and four unpaired trials using a "ABBAABBA" design. Conditioning trials were composed of one flavored liquid followed by 60-min access to wheel running. For the unpaired trials, rats received a different flavor not followed by the opportunity to run. All rats were then initially tested for water consumption followed by tests of the two flavors (paired or unpaired) in a counterbalanced design. Rats in the UW group show no CTA to the liquid paired with wheel running, whereas LW and HC groups developed CTA. These results indicate that pre-exposure to wheel running (i.e., the UCS), eliminates subsequent CTA.

Assessment of Solder Joint Fatigue Life Under Realistic Service Conditions

NASA Astrophysics Data System (ADS)

Hamasha, Sa'd.; Jaradat, Younis; Qasaimeh, Awni; Obaidat, Mazin; Borgesen, Peter

2014-12-01

The behavior of lead-free solder alloys under complex loading scenarios is still not well understood. Common damage accumulation rules fail to account for strong effects of variations in cycling amplitude, and random vibration test results cannot be interpreted in terms of performance under realistic service conditions. This is a result of the effects of cycling parameters on materials properties. These effects are not yet fully understood or quantitatively predictable, preventing modeling based on parameters such as strain, work, or entropy. Depending on the actual spectrum of amplitudes, Miner's rule of linear damage accumulation has been shown to overestimate life by more than an order of magnitude, and greater errors are predicted for other combinations. Consequences may be particularly critical for so-called environmental stress screening. Damage accumulation has, however, been shown to scale with the inelastic work done, even if amplitudes vary. This and the observation of effects of loading history on subsequent work per cycle provide for a modified damage accumulation rule which allows for the prediction of life. Individual joints of four different Sn-Ag-Cu-based solder alloys (SAC305, SAC105, SAC-Ni, and SACXplus) were cycled in shear at room temperature, alternating between two different amplitudes while monitoring the evolution of the effective stiffness and work per cycle. This helped elucidate general trends and behaviors that are expected to occur in vibrations of microelectronics assemblies. Deviations from Miner's rule varied systematically with the combination of amplitudes, the sequences of cycles, and the strain rates in each. The severity of deviations also varied systematically with Ag content in the solder, but major effects were observed for all the alloys. A systematic analysis was conducted to assess whether scenarios might exist in which the more fatigue-resistant high-Ag alloys would fail sooner than the lower-Ag ones.

Impacts of freeway traffic conditions on in-vehicle exposure to ultrafine particulate matter

NASA Astrophysics Data System (ADS)

Bigazzi, Alexander Y.; Figliozzi, Miguel A.

2012-12-01

There is evidence of adverse health impacts from human exposure to traffic-related ultrafine particulate matter pollution. As more commuters are spending a significant portion of their daily routine inside vehicles, it is increasingly relevant to study exposure levels to harmful pollutants inside the vehicle microenvironment. This study is one of the first research efforts to combine detailed freeway traffic data (at 20 s intervals) and in-vehicle ultrafine particulate (UFP) exposure data under varying vehicle ventilation conditions. Results show that due to negative correlation between traffic speed and density, traffic states have a small but significant impact on in-vehicle UFP concentrations, highest in high traffic flow-high speed conditions or in high traffic density-low speed conditions. Vehicle cabin barrier effects are the primary determinant of in-vehicle exposure concentrations, providing 15% protection with the windows down, 47% protection with the windows up and the vent open, and 83-90% protection with the windows up and the vent closed (more with the air conditioning on). Unique results from this study include the dominance of ventilation over traffic effects on UFP and the non-linear relationships between traffic variables and UFP concentrations. The results of this research have important implications for exposure modeling and potential exposure mitigation strategies.

Novel high-fidelity realistic explosion damage simulation for urban environments

NASA Astrophysics Data System (ADS)

Liu, Xiaoqing; Yadegar, Jacob; Zhu, Youding; Raju, Chaitanya; Bhagavathula, Jaya

2010-04-01

Realistic building damage simulation has a significant impact in modern modeling and simulation systems especially in diverse panoply of military and civil applications where these simulation systems are widely used for personnel training, critical mission planning, disaster management, etc. Realistic building damage simulation should incorporate accurate physics-based explosion models, rubble generation, rubble flyout, and interactions between flying rubble and their surrounding entities. However, none of the existing building damage simulation systems sufficiently faithfully realize the criteria of realism required for effective military applications. In this paper, we present a novel physics-based high-fidelity and runtime efficient explosion simulation system to realistically simulate destruction to buildings. In the proposed system, a family of novel blast models is applied to accurately and realistically simulate explosions based on static and/or dynamic detonation conditions. The system also takes account of rubble pile formation and applies a generic and scalable multi-component based object representation to describe scene entities and highly scalable agent-subsumption architecture and scheduler to schedule clusters of sequential and parallel events. The proposed system utilizes a highly efficient and scalable tetrahedral decomposition approach to realistically simulate rubble formation. Experimental results demonstrate that the proposed system has the capability to realistically simulate rubble generation, rubble flyout and their primary and secondary impacts on surrounding objects including buildings, constructions, vehicles and pedestrians in clusters of sequential and parallel damage events.

Pre-exposure to cocaine or morphine attenuates taste avoidance conditioning in adolescent rats: Drug specificity in the US pre-exposure effect.

PubMed

Clasen, Matthew M; Hempel, Briana J; Riley, Anthony L

2017-05-01

Although the attenuating effects of drug history on conditioned taste avoidance (CTA) learning have been widely investigated in adults, such effects in adolescents have not been well characterized. Recent research has suggested that the display of the drug pre-exposure effect during adolescence may be drug dependent given that pre-exposure to ethanol attenuates subsequent conditioning, whereas pre-exposure to the classic emetic lithium chloride (LiCl) fails to do so. The present study began investigating the possible drug-dependent nature of the effects of drug pre-exposure by pre-exposing and conditioning adolescent male Sprague-Dawley rats to drugs from two additional classes, specifically psychostimulants (cocaine; Experiment 1) and opioids (morphine; Experiment 2). Consistent with prior work with ethanol (but not LiCl), prior exposure to both cocaine and morphine attenuated taste avoidance induced by these compounds. Although this work supports the view of drug-dependent pre-exposure effects on taste avoidance learning during adolescence, research is needed to assess its mechanisms. © 2017 Wiley Periodicals, Inc.

Neuropsychiatric conditions associated with anesthesia exposure.

PubMed

Gross, Anne F; Stern, Theodore A

2014-01-01

Although anesthetics have been used for more than a century, their mechanisms of action remain poorly understood. Given that a number of intraoperative and postoperative neuropsychiatric syndromes have been linked to the use of anesthetics, practitioners should familiarize themselves with these conditions. Basic concepts about anesthesia are reviewed and neuropsychiatric syndromes associated with anesthesia exposure described. Emergence delirium, postoperative delirium, postoperative cognitive dysfunction, and intraoperative awareness can develop in association with use of inhalation anesthetics and intravenously administered anesthetics. Copyright © 2014 The Academy of Psychosomatic Medicine. Published by Elsevier Inc. All rights reserved.

DESIGN STRATEGY FOR ASSESSING MULTI-PATHWAY EXPOSURE FOR CHILDREN: THE MINNESOTA CHILDREN'S PESTICIDE EXPOSURE STUDY (MNCPES)

EPA Science Inventory

Although children are exposed to a variety of environmental hazards, including pesticides, there is a scarcity of information available to estimate exposures realistically. This article reports on one of the first attempts to measure multi-pathway pesticide exposures in a popu...

Occupational noise exposure, psychosocial working conditions and the risk of tinnitus.

PubMed

Frederiksen, Thomas Winther; Ramlau-Hansen, Cecilia Høst; Stokholm, Zara Ann; Grynderup, Matias Brødsgaard; Hansen, Åse Marie; Lund, Søren Peter; Kristiansen, Jesper; Vestergaard, Jesper Medom; Bonde, Jens Peter; Kolstad, Henrik Albert

2017-02-01

The purpose of this study was to evaluate the influence of occupational noise (current and cumulative doses) and psychosocial work factors (psychological demands and decision latitude) on tinnitus occurrence among workers, using objective and non-self-reported exposure measures to prevent reporting bias. In a cross-sectional study, we analyzed data from a Danish survey from 2009 to 2010 that included 534 workers from children day care units and 10 manufacturing trades. Associations between risk factors (current noise exposure, cumulative noise exposure and psychosocial working conditions) and tinnitus were analyzed with logistic regression. We found no statistically significant associations between either current [OR 0.95 (95% CI 0.89; 1.01)] or cumulative [OR 0.93 (95% CI 0.81; 1.06)] occupational noise exposure and tinnitus. Likewise, results for psychosocial working conditions showed no statistically significant association between work place decision latitude [OR 1.06 (95% CI 0.94; 1.13)] or psychological demands [OR 1.07 (95% CI 0.90; 1.26)] and tinnitus. Our results suggest that current Danish occupational noise levels (in combination with relevant noise protection) are not associated with tinnitus. Also, results indicated that the psychosocial working conditions we observed in this cohort of mainly industrial workers were not associated with tinnitus. Therefore, psychosocial working conditions comparable to those observed in this study are probably not relevant to take into account in the evaluation of workers presenting with tinnitus.

Children's Responses to Contrasting 'Realistic' Mathematics Problems: Just How Realistic Are Children Ready To Be?

ERIC Educational Resources Information Center

Cooper, Barry; Harries, Tony

2002-01-01

Analyzes 11-12-year-old English children's responses to two 'realistic' problems. Through a comparison of responses to two items, suggests that, given suitable 'realistic' problems, many children may be more willing and able to introduce realistic responses in a testing context than earlier research might lead one to expect. (Author/MM)

Simulation of realistic retinoscopic measurement

NASA Astrophysics Data System (ADS)

Tan, Bo; Chen, Ying-Ling; Baker, K.; Lewis, J. W.; Swartz, T.; Jiang, Y.; Wang, M.

2007-03-01

Realistic simulation of ophthalmic measurements on normal and diseased eyes is presented. We use clinical data of ametropic and keratoconus patients to construct anatomically accurate three-dimensional eye models and simulate the measurement of a streak retinoscope with all the optical elements. The results show the clinical observations including the anomalous motion in high myopia and the scissors reflex in keratoconus. The demonstrated technique can be applied to other ophthalmic instruments and to other and more extensively abnormal eye conditions. It provides promising features for medical training and for evaluating and developing ocular instruments.

Impaired vascular function after exposure to diesel exhaust generated at urban transient running conditions

PubMed Central

2010-01-01

Background Traffic emissions including diesel engine exhaust are associated with increased respiratory and cardiovascular morbidity and mortality. Controlled human exposure studies have demonstrated impaired vascular function after inhalation of exhaust generated by a diesel engine under idling conditions. Objectives To assess the vascular and fibrinolytic effects of exposure to diesel exhaust generated during urban-cycle running conditions that mimic ambient 'real-world' exposures. Methods In a randomised double-blind crossover study, eighteen healthy male volunteers were exposed to diesel exhaust (approximately 250 μg/m3) or filtered air for one hour during intermittent exercise. Diesel exhaust was generated during the urban part of the standardized European Transient Cycle. Six hours post-exposure, vascular vasomotor and fibrinolytic function was assessed during venous occlusion plethysmography with intra-arterial agonist infusions. Measurements and Main Results Forearm blood flow increased in a dose-dependent manner with both endothelial-dependent (acetylcholine and bradykinin) and endothelial-independent (sodium nitroprusside and verapamil) vasodilators. Diesel exhaust exposure attenuated the vasodilatation to acetylcholine (P < 0.001), bradykinin (P < 0.05), sodium nitroprusside (P < 0.05) and verapamil (P < 0.001). In addition, the net release of tissue plasminogen activator during bradykinin infusion was impaired following diesel exhaust exposure (P < 0.05). Conclusion Exposure to diesel exhaust generated under transient running conditions, as a relevant model of urban air pollution, impairs vasomotor function and endogenous fibrinolysis in a similar way as exposure to diesel exhaust generated at idling. This indicates that adverse vascular effects of diesel exhaust inhalation occur over different running conditions with varying exhaust composition and concentrations as well as physicochemical particle properties. Importantly, exposure to diesel exhaust

A conformally flat realistic anisotropic model for a compact star

NASA Astrophysics Data System (ADS)

Ivanov, B. V.

2018-04-01

A physically realistic stellar model with a simple expression for the energy density and conformally flat interior is found. The relations between the different conditions are used without graphic proofs. It may represent a real pulsar.

The effects of nicotine exposure during Pavlovian conditioning in rats on several measures of incentive motivation for a conditioned stimulus paired with water.

PubMed

Guy, Elizabeth Glenn; Fletcher, Paul J

2014-06-01

Nicotine enhances approach toward and operant responding for conditioned stimuli (CSs), but the effect of exposure during different phases of Pavlovian incentive learning on these measures remains to be determined. These studies examined the effects of administering nicotine early, late or throughout Pavlovian conditioning trials on discriminated approach behavior, nicotine-enhanced responding for conditioned reinforcement, extinction, and the reinstatement of responding for conditioned reinforcement. We also tested the effect of nicotine on approach to a lever-CS in a Pavlovian autoshaping procedure and for this CS to serve as a conditioned reinforcer. Thirsty rats were exposed to 13 conditioning sessions where a light/tone CS was paired with the delivery of water. Nicotine was administered either prior to the first or last seven sessions, or throughout the entire conditioning procedure. Responding for conditioned reinforcement, extinction, and the reinstatement of responding by the stimulus and nicotine were compared across exposure groups. Separately, the effects of nicotine on conditioned approach toward a lever-CS during autoshaping, and responding for that CS as a conditioned reinforcer, were examined. Nicotine exposure was necessary for nicotine-enhanced responding for conditioned reinforcement and the ability for nicotine and the stimulus to additively reinstate responding on the reinforced lever. Nicotine increased contacts with a lever-CS during autoshaping, and removal of nicotine abolished this effect. Prior nicotine exposure was necessary for nicotine-enhanced responding reinforced by the lever. Enhancements in the motivating properties of CSs by nicotine occur independently from duration and timing effects of nicotine exposure during conditioning.

Effects of Recent Exposure to a Conditioned Stimulus on Extinction of Pavlovian Fear Conditioning

ERIC Educational Resources Information Center

Chan, Wan Yee Macy; Leung, Hiu T.; Westbrook, R. Frederick; McNally, Gavan P.

2010-01-01

In six experiments we studied the effects of a single re-exposure to a conditioned stimulus (CS; "retrieval trial") prior to extinction training (extinction-reconsolidation boundary) on the development of and recovery from fear extinction. A single retrieval trial prior to extinction training significantly augmented the renewal and reinstatement…

Kinetics of devolatilization and oxidation of a pulverized biomass in an entrained flow reactor under realistic combustion conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jimenez, Santiago; Remacha, Pilar; Ballester, Javier

2008-03-15

In this paper the results of a complete set of devolatilization and combustion experiments performed with pulverized ({proportional_to}500 {mu}m) biomass in an entrained flow reactor under realistic combustion conditions are presented. The data obtained are used to derive the kinetic parameters that best fit the observed behaviors, according to a simple model of particle combustion (one-step devolatilization, apparent oxidation kinetics, thermally thin particles). The model is found to adequately reproduce the experimental trends regarding both volatile release and char oxidation rates for the range of particle sizes and combustion conditions explored. The experimental and numerical procedures, similar to those recentlymore » proposed for the combustion of pulverized coal [J. Ballester, S. Jimenez, Combust. Flame 142 (2005) 210-222], have been designed to derive the parameters required for the analysis of biomass combustion in practical pulverized fuel configurations and allow a reliable characterization of any finely pulverized biomass. Additionally, the results of a limited study on the release rate of nitrogen from the biomass particle along combustion are shown. (author)« less

Realistic full wave modeling of focal plane array pixels

DOE PAGES

Campione, Salvatore; Warne, Larry K.; Jorgenson, Roy E.; ...

2017-11-01

Here, we investigate full-wave simulations of realistic implementations of multifunctional nanoantenna enabled detectors (NEDs). We focus on a 2x2 pixelated array structure that supports two wavelengths of operation. We design each resonating structure independently using full-wave simulations with periodic boundary conditions mimicking the whole infinite array. We then construct a supercell made of a 2x2 pixelated array with periodic boundary conditions mimicking the full NED; in this case, however, each pixel comprises 10-20 antennas per side. In this way, the cross-talk between contiguous pixels is accounted for in our simulations. We observe that, even though there are finite extent effects,more » the pixels work as designed, each responding at the respective wavelength of operation. This allows us to stress that realistic simulations of multifunctional NEDs need to be performed to verify the design functionality by taking into account finite extent and cross-talk effects.« less

Effects of field-realistic doses of glyphosate on honeybee appetitive behaviour.

PubMed

Herbert, Lucila T; Vázquez, Diego E; Arenas, Andrés; Farina, Walter M

2014-10-01

Glyphosate (GLY) is a broad-spectrum herbicide used for weed control. The sub-lethal impact of GLY on non-target organisms such as insect pollinators has not yet been evaluated. Apis mellifera is the main pollinator in agricultural environments and is a well-known model for behavioural research. Honeybees are also accurate biosensors of environmental pollutants and their appetitive behavioural response is a suitable tool with which to test sub-lethal effects of agrochemicals. We studied the effects of field-realistic doses of GLY on honeybees exposed chronically or acutely to the herbicide. We focused on sucrose sensitivity, elemental and non-elemental associative olfactory conditioning of the proboscis extension response (PER), and foraging-related behaviour. We found a reduced sensitivity to sucrose and learning performance for the groups chronically exposed to GLY concentrations within the range of recommended doses. When olfactory PER conditioning was performed with sucrose reward with the same GLY concentrations (acute exposure), elemental learning and short-term memory retention decreased significantly compared with controls. Non-elemental associative learning was also impaired by an acute exposure to GLY traces. Altogether, these results imply that GLY at concentrations found in agro-ecosystems as a result of standard spraying can reduce sensitivity to nectar reward and impair associative learning in honeybees. However, no effect on foraging-related behaviour was found. Therefore, we speculate that successful forager bees could become a source of constant inflow of nectar with GLY traces that could then be distributed among nestmates, stored in the hive and have long-term negative consequences on colony performance. © 2014. Published by The Company of Biologists Ltd.

Chronic exposure to neonicotinoids reduces honey bee health near corn crops.

PubMed

Tsvetkov, N; Samson-Robert, O; Sood, K; Patel, H S; Malena, D A; Gajiwala, P H; Maciukiewicz, P; Fournier, V; Zayed, A

2017-06-30

Experiments linking neonicotinoids and declining bee health have been criticized for not simulating realistic exposure. Here we quantified the duration and magnitude of neonicotinoid exposure in Canada's corn-growing regions and used these data to design realistic experiments to investigate the effect of such insecticides on honey bees. Colonies near corn were naturally exposed to neonicotinoids for up to 4 months-the majority of the honey bee's active season. Realistic experiments showed that neonicotinoids increased worker mortality and were associated with declines in social immunity and increased queenlessness over time. We also discovered that the acute toxicity of neonicotinoids to honey bees doubles in the presence of a commonly encountered fungicide. Our work demonstrates that field-realistic exposure to neonicotinoids can reduce honey bee health in corn-growing regions. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Sex and Adolescent Ethanol Exposure Influence Pavlovian Conditioned Approach

PubMed Central

Madayag, Aric C.; Stringfield, Sierra J.; Reissner, Kathryn J.; Boettiger, Charlotte A.; Robinson, Donita L.

2017-01-01

BACKGROUND Alcohol use among adolescents is widespread and a growing concern due to long-term behavioral deficits, including altered Pavlovian behavior, that potentially contribute to addiction vulnerability. We tested the hypothesis that adolescent intermittent ethanol (AIE) exposure alters Pavlovian behavior in males and females as measured by a shift from goal-tracking to sign-tracking. Additionally, we investigated GLT-1, an astrocytic glutamate transporter, as a potential contributor to a sign-tracking phenotype. METHODS Male and female Sprague-Dawley rats were exposed to AIE (5g/Kg, intragastric) or water intermittently 2 days on, 2 days off from postnatal day (P) 25 to 54. Around P70, animals began 20 daily sessions of Pavlovian conditioned approach, where they learned that a cue predicted non-contingent reward delivery. Lever pressing indicated interaction with the cue, or sign-tracking, and receptacle entries indicated approach to the reward delivery location, or goal-tracking. To test for effects of AIE on nucleus accumbens excitatory signaling, we isolated membrane subfractions and measured protein levels of the glutamate transporter GLT-1 after animals completed behavior as a measure of glutamate homeostasis. RESULTS Females exhibited elevated sign-tracking compared to males with significantly more lever presses, faster latency to first lever press, and greater probability to lever press in a trial. AIE significantly increased lever pressing while blunting goal tracking, as indicated by fewer cue-evoked receptacle entries, slower latency to receptacle entry, and lower probability to enter the receptacle in a trial. No significant Sex-by-Exposure interactions were observed in sign- or goal-tracking metrics. Moreover, we found no significant effects of Sex or Exposure on membrane GLT-1 expression in the nucleus accumbens. CONCLUSIONS Females exhibited enhanced sign-tracking compared to males, while AIE decreased goal-tracking compared to control exposure

Chemical changes exhibited by latent fingerprints after exposure to vacuum conditions.

PubMed

Bright, Nicholas J; Willson, Terry R; Driscoll, Daniel J; Reddy, Subrayal M; Webb, Roger P; Bleay, Stephen; Ward, Neil I; Kirkby, Karen J; Bailey, Melanie J

2013-07-10

The effect of vacuum exposure on latent fingerprint chemistry has been evaluated. Fingerprints were analysed using a quartz crystal microbalance to measure changes in mass, gas chromatography mass spectrometry to measure changes in lipid composition and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to determine changes in the content of water, fatty acids and their esters after exposure to vacuum. The results are compared with samples aged under ambient conditions. It was found that fingerprints lose around 26% of their mass when exposed to vacuum conditions, equivalent to around 5 weeks ageing under ambient conditions. Further exposure to vacuum causes a significant reduction in the lipid composition of a fingerprint, in particular with the loss of tetradecanoic and pentadecanoic acid, that was not observed in ambient aged samples. There are therefore implications for sequence in which fingerprint development procedures (for example vacuum metal deposition) are carried out, as well as the use of vacuum based methods such as secondary ion mass spectrometry (SIMS) and matrix-assisted laser desorption ionisation (MALDI) in the study of fingerprint chemistry. Copyright © 2013. Published by Elsevier Ireland Ltd.

Realists, Radicals, and Rainbows. The Twenty-Eighth Amy Morris Homans Lecture 1994.

ERIC Educational Resources Information Center

Bennett, Roberta S.

1995-01-01

Challenges physical education professionals to be realists who name the conditions around them that divide according to group identity and thus perpetuate injustice; to be radicals who work to change conditions; and to build and follow a rainbow path to a future where social justice, human rights, and the human condition are first priorities. (JB)

Working conditions and occupational risk exposure in employees driving for work.

PubMed

Fort, Emmanuel; Ndagire, Sheba; Gadegbeku, Blandine; Hours, Martine; Charbotel, Barbara

2016-04-01

An analysis of the occupational constraints and exposures to which employees facing road risk at work are subject was performed, with comparison versus non-exposed employees. Objective was to improve knowledge of the characteristics of workers exposed to road risk in France and of the concomitant occupational constraints. The descriptive study was based on data from the 2010 SUMER survey (Medical Monitoring of Occupational Risk Exposure: Surveillance Médicale des Expositions aux Risques professionnels), which included data not only on road risk exposure at work but also on a range of socio-occupational factors and working conditions. The main variable of interest was "driving (car, truck, bus, coach, etc.) on public thoroughfares" for work (during the last week of work). This was a dichotomous "Yes/No" variable, distinguishing employees who drove for work; it also comprised 4-step weekly exposure duration: <2h, 2-10h, 10-20h and ≥20h. 75% of the employees with driving exposure were male. Certain socio-occupational categories were found significantly more frequently: professional drivers (INSEE occupations and socio-occupational categories (PCS) 64), skilled workers (PCS 61), intermediate professions and teaching, health, civil service (functionaries) and assimilated (PCS 46) and company executives (PCS 36). Employees with driving exposure more often worked in small businesses or establishments. Constraints in terms of schedule and work-time were more frequent in employees with driving exposure. Constraints in terms of work rhythm were more frequent in non-exposed employees, with the exception of external demands requiring immediate response. On the Karasek's Job Demand-Control Model, employees with driving exposure less often had low decision latitude. Prevalence of job-strain was also lower, as was prevalence of "iso-strain" (combination of job-strain and social isolation). Employees with driving exposure were less often concerned by hostile behavior and, when

Use of polar organic chemical integrative samplers to assess the effects of chronic pesticide exposure on biofilms.

PubMed

Morin, Soizic; Pesce, Stéphane; Kim-Tiam, Sandra; Libert, Xavier; Coquery, Marina; Mazzella, Nicolas

2012-07-01

The responses of aquatic organisms to chronic exposure to environmental concentrations of toxicants, often found in mixtures, are poorly documented. Here passive sampler extracts were used in experimental contamination of laboratory channels, to investigate their effects on natural biofilm communities. A realistic mixture of pesticides extracted from Polar Organic Chemical Integrative Samplers was used to expose biofilms in laboratory channels to total pesticide concentrations averaging 0.5 ± 0.1 μg l⁻¹. The level of exposure was representative of field conditions in terms of relative proportions of the substances but the exposure concentration was not maintained (decreasing concentrations between contamination occasions). The impact on the structural as well as the functional characteristics of the autotrophic and heterotrophic components was determined, using biofilm grown in uncontaminated conditions (reference site) and in sites exposed to pesticides (contaminated site). The exposure imposed did not significantly modify the structure or functions of reference biofilms, nor did it modify tolerance as measured by mixture EC₅₀ (EC₅₀ mix). In contrast, the communities from the more contaminated downstream section lost tolerance following decreased dose exposure, but community composition remained fairly stable. Overall, these results indicate that low levels of contamination did not lead to strong changes in community structure, and 14-day changes in tolerance seemed to depend mainly on physiological adaptation, suggesting that other environmental factors or longer-lasting processes prevailed. This study reports the first attempt to use passive sampler extracts as a realistic composite contaminant for experimental exposure of biofilms, with promising perspectives in further ecotoxicology studies.

Helping With All Your Heart: Realistic Heart Stimulus and Compliance With an Organ Donation Request.

PubMed

Jacob, Céline; Guéguen, Nicolas

2015-01-01

Pictures and images are important aspects in fundraising advertising and could generate more donations. In two experimental studies, we examined the effect of various pictures of hearts on compliance with a request for organ donations. The solicitor wore a white tee shirt where various forms of hearts were printed: symbolic versus realistic (first experiment), none versus symbolic versus realistic (second experiment). Results showed that more compliance was found in the realistic heart experimental condition whereas the symbolic heart form had no significant effect.

Fault tree analysis for exposure to refrigerants used for automotive air conditioning in the United States.

PubMed

Jetter, J J; Forte, R; Rubenstein, R

2001-02-01

A fault tree analysis was used to estimate the number of refrigerant exposures of automotive service technicians and vehicle occupants in the United States. Exposures of service technicians can occur when service equipment or automotive air-conditioning systems leak during servicing. The number of refrigerant exposures of service technicians was estimated to be 135,000 per year. Exposures of vehicle occupants can occur when refrigerant enters passenger compartments due to sudden leaks in air-conditioning systems, leaks following servicing, or leaks caused by collisions. The total number of exposures of vehicle occupants was estimated to be 3,600 per year. The largest number of exposures of vehicle occupants was estimated for leaks caused by collisions, and the second largest number of exposures was estimated for leaks following servicing. Estimates used in the fault tree analysis were based on a survey of automotive air-conditioning service shops, the best available data from the literature, and the engineering judgement of the authors and expert reviewers from the Society of Automotive Engineers Interior Climate Control Standards Committee. Exposure concentrations and durations were estimated and compared with toxicity data for refrigerants currently used in automotive air conditioners. Uncertainty was high for the estimated numbers of exposures, exposure concentrations, and exposure durations. Uncertainty could be reduced in the future by conducting more extensive surveys, measurements of refrigerant concentrations, and exposure monitoring. Nevertheless, the analysis indicated that the risk of exposure of service technicians and vehicle occupants is significant, and it is recommended that no refrigerant that is substantially more toxic than currently available substitutes be accepted for use in vehicle air-conditioning systems, absent a means of mitigating exposure.

Keeping It Real: How Realistic Does Realistic Fiction for Children Need to Be?

ERIC Educational Resources Information Center

O'Connor, Barbara

2010-01-01

O'Connor, an author of realistic fiction for children, shares her attempts to strike a balance between carefree, uncensored, authentic, realistic writing and age-appropriate writing. Of course, complicating that balancing act is the fact that what seems age-appropriate to her might not seem so to everyone. O'Connor suggests that while it may be…

The effectiveness and cost-effectiveness of shared care: protocol for a realist review.

PubMed

Hardwick, Rebecca; Pearson, Mark; Byng, Richard; Anderson, Rob

2013-02-12

Shared care (an enhanced information exchange over and above routine outpatient letters) is commonly used to improve care coordination and communication between a specialist and primary care services for people with long-term conditions. Evidence of the effectiveness and cost-effectiveness of shared care is mixed. Informed decision-making for targeting shared care requires a greater understanding of how it works, for whom it works, in what contexts and why. This protocol outlines how realist review methods can be used to synthesise evidence on shared care for long-term conditions.A further aim of the review is to explore economic evaluations of shared care. Economic evaluations are difficult to synthesise due to problems in accounting for contextual differences that impact on resource use and opportunity costs. Realist review methods have been suggested as a way to overcome some of these issues, so this review will also assess whether realist review methods are amenable to synthesising economic evidence. Database and web searching will be carried out in order to find relevant evidence to develop and test programme theories about how shared care works. The review will have two phases. Phase 1 will concentrate on the contextual conditions and mechanisms that influence how shared care works, in order to develop programme theories, which partially explain how it works. Phase 2 will focus on testing these programme theories. A Project Reference Group made up of health service professionals and people with actual experience of long-term conditions will be used to ground the study in real-life experience. Review findings will be disseminated through local and sub-national networks for integrated care and long-term conditions. This realist review will explore why and for whom shared care works, in order to support decision-makers working to improve the effectiveness of care for people outside hospital. The development of realist review methods to take into account cost and

Nanoparticle exposure at nanotechnology workplaces: A review

PubMed Central

2011-01-01

Risk, associated with nanomaterial use, is determined by exposure and hazard potential of these materials. Both topics cannot be evaluated absolutely independently. Realistic dose concentrations should be tested based on stringent exposure assessments for the corresponding nanomaterial taking into account also the environmental and product matrix. This review focuses on current available information from peer reviewed publications related to airborne nanomaterial exposure. Two approaches to derive realistic exposure values are differentiated and independently presented; those based on workplace measurements and the others based on simulations in laboratories. An assessment of the current available workplace measurement data using a matrix, which is related to nanomaterials and work processes, shows, that data are available on the likelihood of release and possible exposure. Laboratory studies are seen as an important complementary source of information on particle release processes and hence for possible exposure. In both cases, whether workplace measurements or laboratories studies, the issue of background particles is a major problem. From this review, major areas for future activities and focal points are identified. PMID:21794132

[Some aspects of animal-to-human approximation of low frequency electromagnetic field exposure conditions].

PubMed

Vasin, A L

2003-01-01

Appropriateness of representation of a biological object surface as an equipotential surface has been proved for conditions of a quasistatic exposure to EMF of frequencies lower than 1 MHz. The conditions, at which a self capacitance of a biological object is its basic electrical parameter, have been considered. A factor of animal-to-human approximation of low-frequency EMF exposure conditions was estimated on the basis of equal dose loading in biological objects of different geometric sizes.

Realistic Evaluation of Titanium Dioxide Nanoparticle Exposure in Chewing Gum.

PubMed

Fiordaliso, Fabio; Foray, Claudia; Salio, Monica; Salmona, Mario; Diomede, Luisa

2018-06-20

There is growing concern about the presence of nanoparticles (NPs) in titanium dioxide (TiO 2 ) as food additive (E171). To realistically estimate the number and the amount of TiO 2 NPs ingested with food, we applied a transmission electron microscopy method combined with inductively coupled plasma optical emission spectrometry. Different percentages of TiO 2 NPs (6-18%) were detected in E171 from various suppliers. In the eight chewing gums analyzed as food prototypes, TiO 2 NPs were absent in one sample and ranged 0.01-0.66 mg/gum, corresponding to 7-568 billion NPs/gum, in the other seven. We estimated that the mass-based TiO 2 NPs ingested with chewing gums by the European population ranged from 0.28 to 112.40 μg/kg b.w./day, and children ingested more nanosized titanium than adolescents and adults. Although this level may appear negligible it corresponds to 0.1-84 billion TiO 2 NPs/kg b.w/day, raising important questions regarding their potential accumulation in the body, possibly causing long-term effects on consumers' health.

Enhanced Eyeblink Conditioning in Behaviorally Inhibited Individuals is Disrupted by Proactive Interference Following US Alone Pre-exposures.

PubMed

Allen, Michael Todd; Miller, Daniel P

2016-01-01

Anxiety vulnerable individuals exhibit enhanced acquisition of conditioned eyeblinks as well as enhanced proactive interference from conditioned stimulus (CS) or unconditioned stimulus (US) alone pre-exposures (Holloway et al., 2012). US alone pre-exposures disrupt subsequent conditioned response (CR) acquisition to CS-US paired trials as compared to context pre-exposure controls. While Holloway et al. (2012) reported enhanced acquisition in high trait anxiety individuals in the context condition, anxiety vulnerability effects were not reported for the US alone pre-exposure group. It appears from the published data that there were no differences between high and low anxiety individuals in the US alone condition. In the work reported here, we sought to extend the findings of enhanced proactive interference with US alone pre-exposures to determine if the enhanced conditioning was disrupted by proactive interference procedures. We also were interested in the spontaneous eyeblinks during the pre-exposure phase of training. We categorized individuals as anxiety vulnerability or non-vulnerable individuals based scores on the Adult Measure of Behavioral Inhibition (AMBI). Sixty-six participants received 60 trials consisting of 30 US alone or context alone pre-exposures followed by 30 CS-US trials. US alone pre-exposures not only disrupted CR acquisition overall, but behaviorally inhibited (BI) individuals exhibited enhanced proactive interference as compared to non-inhibited (NI) individuals. In addition, US alone pre-exposures disrupted the enhanced acquisition observed in BI individuals as compared to NI individuals following context alone pre-exposures. Differences were also found in rates of spontaneous eyeblinks between BI and NI individuals during context pre-exposure. Our findings will be discussed in the light of the neural substrates of eyeblink conditioning as well as possible factors such as hypervigilance in the amygdala and hippocampal systems, and possible

Enhanced Eyeblink Conditioning in Behaviorally Inhibited Individuals is Disrupted by Proactive Interference Following US Alone Pre-exposures

PubMed Central

Allen, Michael Todd; Miller, Daniel P.

2016-01-01

Anxiety vulnerable individuals exhibit enhanced acquisition of conditioned eyeblinks as well as enhanced proactive interference from conditioned stimulus (CS) or unconditioned stimulus (US) alone pre-exposures (Holloway et al., 2012). US alone pre-exposures disrupt subsequent conditioned response (CR) acquisition to CS-US paired trials as compared to context pre-exposure controls. While Holloway et al. (2012) reported enhanced acquisition in high trait anxiety individuals in the context condition, anxiety vulnerability effects were not reported for the US alone pre-exposure group. It appears from the published data that there were no differences between high and low anxiety individuals in the US alone condition. In the work reported here, we sought to extend the findings of enhanced proactive interference with US alone pre-exposures to determine if the enhanced conditioning was disrupted by proactive interference procedures. We also were interested in the spontaneous eyeblinks during the pre-exposure phase of training. We categorized individuals as anxiety vulnerability or non-vulnerable individuals based scores on the Adult Measure of Behavioral Inhibition (AMBI). Sixty-six participants received 60 trials consisting of 30 US alone or context alone pre-exposures followed by 30 CS-US trials. US alone pre-exposures not only disrupted CR acquisition overall, but behaviorally inhibited (BI) individuals exhibited enhanced proactive interference as compared to non-inhibited (NI) individuals. In addition, US alone pre-exposures disrupted the enhanced acquisition observed in BI individuals as compared to NI individuals following context alone pre-exposures. Differences were also found in rates of spontaneous eyeblinks between BI and NI individuals during context pre-exposure. Our findings will be discussed in the light of the neural substrates of eyeblink conditioning as well as possible factors such as hypervigilance in the amygdala and hippocampal systems, and possible

Effects of carbaryl on green frog (Rana clamitans) tadpoles: Timing of exposure versus multiple exposures

USGS Publications Warehouse

Boone, M.D.; Bridges, C.M.

2003-01-01

The majority of studies on pesticide impacts have evaluated the effects of single exposures. However, multiple exposures to a pesticide may be more prevalent. The objective of our study was to determine how multiple exposures versus single exposure at different times during development affected survival to metamorphosis, tadpole survival, tadpole mass, and tadpole developmental stage of green frog (Rana clamitans) tadpoles reared at low and high density in outdoor cattle tank ponds. Tadpoles were exposed to carbaryl zero, one, two, or three times at 14-d intervals. We applied single doses of carbaryl at one of three times, specifically during early, mid, or late development. Overall, we found that multiple exposures had a greater impact than single exposures during development. More individuals reached metamorphosis in ponds exposed to multiple doses of carbaryl compared with controls, indicating that the presence of carbaryl stimulated metamorphosis. The presence of carbaryl in the aquatic environment also resulted in more developed tadpoles compared with controls. Tadpoles in control ponds did not reach metamorphosis and were less developed than individuals exposed to carbaryl; this effect indicates that, under ideal conditions, green frogs could overwinter in ponds so that greater size could be attained before metamorphosis in the following spring or summer. Our study demonstrated the importance of including realistic application procedures when evaluating the effects of a pesticide and that multiple exposures to a short-lived pesticide are more likely to affect an amphibian population.

Atomistic simulations of graphite etching at realistic time scales.

PubMed

Aussems, D U B; Bal, K M; Morgan, T W; van de Sanden, M C M; Neyts, E C

2017-10-01

Hydrogen-graphite interactions are relevant to a wide variety of applications, ranging from astrophysics to fusion devices and nano-electronics. In order to shed light on these interactions, atomistic simulation using Molecular Dynamics (MD) has been shown to be an invaluable tool. It suffers, however, from severe time-scale limitations. In this work we apply the recently developed Collective Variable-Driven Hyperdynamics (CVHD) method to hydrogen etching of graphite for varying inter-impact times up to a realistic value of 1 ms, which corresponds to a flux of ∼10 20 m -2 s -1 . The results show that the erosion yield, hydrogen surface coverage and species distribution are significantly affected by the time between impacts. This can be explained by the higher probability of C-C bond breaking due to the prolonged exposure to thermal stress and the subsequent transition from ion- to thermal-induced etching. This latter regime of thermal-induced etching - chemical erosion - is here accessed for the first time using atomistic simulations. In conclusion, this study demonstrates that accounting for long time-scales significantly affects ion bombardment simulations and should not be neglected in a wide range of conditions, in contrast to what is typically assumed.

A realistic chemical system presenting a self-organized critical behavior

NASA Astrophysics Data System (ADS)

Gaveau, Bernard; Latrémolière, Daniel; Moreau, Michel

2003-04-01

We consider a realistic example of chemical system which presents self-organized criticality. We can study the kinetic equations analytically, and show that the conditions for self-organized criticality are satisfied. We find power relaxation laws for certain variables near the critical state, confirming the self-organized critical behavior.

Acute exposure to realistic acid fog: effects on respiratory function and airway responsiveness in asthmatics.

PubMed

Leduc, D; Fally, S; De Vuyst, P; Wollast, R; Yernault, J C

1995-11-01

Naturally occurring fogs in industrialized cities are contaminated by acidic air pollutants. In Brussels, Belgium, the pH of polluted fogwater may be as low as 3 with osmolarity as low as 30 mOsm. In order to explore short-term respiratory effects of a realistic acid-polluted fog, we collected samples of acid fog in Brussels, Belgium, which is a densely populated and industrialized city, we defined characteristics of this fog and exposed asthmatic volunteers at rest through a face mask to fogs with physical and chemical characteristics similar to those of natural fogs assessed in this urban area. Fogwater was sampled using a screen collector where droplets are collected by inertial impaction and chemical content of fogwater was assessed by measurement of conductivity, pH, visible colorimetry, high pressure liquid chromatography, and atomic absorption spectrophotometry over a period of one year. The fogwater composition was dominated by NH4+ and SO4- ions. First we evaluated the possible effect of fog acidity alone. For this purpose 14 subjects with asthma were exposed at rest for 1 hr [mass median aerodynamic diameter to a large-particle (MMAD), 9 microns] aerosol with H2SO4 concentration of 500 micrograms/m3 (pH 2.5) and osmolarity of 300 mOsm. We did not observe significant change in pulmonary function or bronchial responsiveness to metacholine. In the second part of the work, 10 asthmatic subjects were exposed to acid fog (MMAD, 7 microns) containing sulfate and ammonium ions (major ions recovered in naturally occurring fogs) with pH 3.5 and osmolarity 30 mOsm. Again, pulmonary function and bronchial reactivity were not modified after inhalation of this fog. It was concluded that short-term exposure to acid fog reproducing acidity and hypoosmolarity of natural polluted fogs does not induce bronchoconstriction and does not change bronchial responsiveness in asthmatics.

Improving stamping simulation accuracy by accounting for realistic friction and lubrication conditions: Application to the door-outer of the Mercedes-Benz C-class Coupé

NASA Astrophysics Data System (ADS)

Hol, J.; Wiebenga, J. H.; Stock, J.; Wied, J.; Wiegand, K.; Carleer, B.

2016-08-01

In the stamping of automotive parts, friction and lubrication play a key role in achieving high quality products. In the development process of new automotive parts, it is therefore crucial to accurately account for these effects in sheet metal forming simulations. Only then, one can obtain reliable and realistic simulation results that correspond to the actual try-out and mass production conditions. In this work, the TriboForm software is used to accurately account for tribology-, friction-, and lubrication conditions in stamping simulations. The enhanced stamping simulations are applied and validated for the door-outer of the Mercedes- Benz C-Class Coupe. The project results demonstrate the improved prediction accuracy of stamping simulations with respect to both part quality and actual stamping process conditions.

Hyper-realistic face masks: a new challenge in person identification.

PubMed

Sanders, Jet Gabrielle; Ueda, Yoshiyuki; Minemoto, Kazusa; Noyes, Eilidh; Yoshikawa, Sakiko; Jenkins, Rob

2017-01-01

We often identify people using face images. This is true in occupational settings such as passport control as well as in everyday social environments. Mapping between images and identities assumes that facial appearance is stable within certain bounds. For example, a person's apparent age, gender and ethnicity change slowly, if at all. It also assumes that deliberate changes beyond these bounds (i.e., disguises) would be easy to spot. Hyper-realistic face masks overturn these assumptions by allowing the wearer to look like an entirely different person. If unnoticed, these masks break the link between facial appearance and personal identity, with clear implications for applied face recognition. However, to date, no one has assessed the realism of these masks, or specified conditions under which they may be accepted as real faces. Herein, we examined incidental detection of unexpected but attended hyper-realistic masks in both photographic and live presentations. Experiment 1 (UK; n = 60) revealed no evidence for overt detection of hyper-realistic masks among real face photos, and little evidence of covert detection. Experiment 2 (Japan; n = 60) extended these findings to different masks, mask-wearers and participant pools. In Experiment 3 (UK and Japan; n = 407), passers-by failed to notice that a live confederate was wearing a hyper-realistic mask and showed limited evidence of covert detection, even at close viewing distance (5 vs. 20 m). Across all of these studies, viewers accepted hyper-realistic masks as real faces. Specific countermeasures will be required if detection rates are to be improved.

Oxidation Behavior of Ferritic Stainless Steels under SOFC Interconnect Exposure Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Zhenguo; Walker, Matthew S.; Singh, Prabhakar

The oxidation of ferritic stainless steels has been studied under solid oxide fuel cell (SOFC) interconnect “dual” exposure conditions, i.e. simultaneous exposure to air on one side of the sample, and moist hydrogen on the other side. This paper focuses on the oxidation behavior of ferritic stainless steels during the isothermal oxidation in the dual environments. It was found that scales grown on the air side under these dual exposure conditions can be significantly different from scales grown on samples exposed to air on both sides. In contrast, no substantial difference was observed between the scales grown on the fuelmore » side of the dual atmosphere samples and scales grown on samples exposed to moist hydrogen on both sides. AISI430, with 17% Cr, suffered localized attack via formation of Fe2O3 hematite-rich nodules on the air side of dual exposure samples, while the spinel top layer of the air side scale of Crofer22 APU (23% Cr) was enriched in iron. For E-brite, with the highest Cr content (27%), no unusual phases were found in the scale on the air side, but it was noticed the air side scale was less dense and appeared to be more prone to defects than the scale grown in air only. The anomalous oxidation behavior of ferritic stainless steels on the air side of dual exposure specimens is related to the transport of hydrogen through the steel and its subsequent presence in the air side scale.« less

Laboratory exposure systems to simulate atmospheric degradation of building stone under dry and wet deposition conditions

NASA Astrophysics Data System (ADS)

Johnson, J. B.; Haneef, S. J.; Hepburn, B. J.; Hutchinson, A. J.; Thompson, G. E.; Wood, G. C.

The design philosophy, construction and use of two exposure test systems are described, in which the objective is to simulate the degradation of stone samples under, respectively, the 'dry' and 'wet' deposition of atmospheric pollutants. Some element of realistic acceleration is possible in certain experiments. Particular emphasis is placed upon using known presentation rates of the pollutants, both in respect of typical depositions of pollutants and their oxidation products appropriate for an industrial atmosphere. In the dry deposition rig, SO 2, NO 2, NO, HCl and the oxidant O 3 are presented individually or together at realistic deposition rates. In the wet deposition apparatus, SO 2-4, NO -3 and Cl - at a pH of 3.5, simulating 'acid rain' but in a more concentrated form, are deposited. The dry deposition chamber can be operated at constant relative humidity (typically 84%) with pre-dried or precisely wetted stones to simulate episodic rain wetting, or using other methods of wet/dry cycling, which are also a feature of the wet deposition chamber. Heating and cooling of the samples is also possible, as is the use of shaped or coupled stones of different kinds such as are found in a building facade. The results are illustrated in terms of data on the weight change, the anion content of stone and run-off, the pH change of run-off and the total calcium reacted, using Portland stone, as a prelude to later papers in which behaviour of a whole matrix of stone types and environments is presented and discussed. Such an approach permits the eventual production of 'pollutant-material response' relationships and damage functions for comparison with and prediction of external exposure results.

Considerations of Environmentally Relevant Test Conditions for Improved Evaluation of Ecological Hazards of Engineered Nanomaterials.

PubMed

Holden, Patricia A; Gardea-Torresdey, Jorge L; Klaessig, Fred; Turco, Ronald F; Mortimer, Monika; Hund-Rinke, Kerstin; Cohen Hubal, Elaine A; Avery, David; Barceló, Damià; Behra, Renata; Cohen, Yoram; Deydier-Stephan, Laurence; Ferguson, P Lee; Fernandes, Teresa F; Herr Harthorn, Barbara; Henderson, W Matthew; Hoke, Robert A; Hristozov, Danail; Johnston, John M; Kane, Agnes B; Kapustka, Larry; Keller, Arturo A; Lenihan, Hunter S; Lovell, Wess; Murphy, Catherine J; Nisbet, Roger M; Petersen, Elijah J; Salinas, Edward R; Scheringer, Martin; Sharma, Monita; Speed, David E; Sultan, Yasir; Westerhoff, Paul; White, Jason C; Wiesner, Mark R; Wong, Eva M; Xing, Baoshan; Steele Horan, Meghan; Godwin, Hilary A; Nel, André E

2016-06-21

Engineered nanomaterials (ENMs) are increasingly entering the environment with uncertain consequences including potential ecological effects. Various research communities view differently whether ecotoxicological testing of ENMs should be conducted using environmentally relevant concentrations-where observing outcomes is difficult-versus higher ENM doses, where responses are observable. What exposure conditions are typically used in assessing ENM hazards to populations? What conditions are used to test ecosystem-scale hazards? What is known regarding actual ENMs in the environment, via measurements or modeling simulations? How should exposure conditions, ENM transformation, dose, and body burden be used in interpreting biological and computational findings for assessing risks? These questions were addressed in the context of this critical review. As a result, three main recommendations emerged. First, researchers should improve ecotoxicology of ENMs by choosing test end points, duration, and study conditions-including ENM test concentrations-that align with realistic exposure scenarios. Second, testing should proceed via tiers with iterative feedback that informs experiments at other levels of biological organization. Finally, environmental realism in ENM hazard assessments should involve greater coordination among ENM quantitative analysts, exposure modelers, and ecotoxicologists, across government, industry, and academia.

Exposure assessment through realistic laboratory simulation of a soccer stadium fire.

PubMed

van Belle, N J C; van Putten, E M; de Groot, A C; Meeussen, V J A; Banus, S

2010-10-01

On Sunday April 13, 2008 a fire broke out on a grandstand in the Euroborg soccer stadium in Groningen The Netherlands. The polyamide chairs on the grandstand were set on fire and supporters were exposed to the emitted smoke which induced mild health effects. The Dutch government was concerned about potential health risks that such fires could have to exposed fans. Especially the exposure to toxic fumes was considered a risk because prior research has proven that large amounts of chemical compounds are emitted during the burning of chemical substances such as polyamide. Among these emitted compounds are HCN, CO, NO(x), NH(3) and volatile organic compounds. To study if supporters were exposed to hazardous chemical compounds we designed a laboratory controlled replica of a part of the grandstand of the Euroborg stadium to perform fire-experiments. This simulation of the fire under controlled circumstances proved that a wide variety of chemicals were emitted. Especially the emission of CO and NO(x) were high, but also the emission of formaldehyde might be toxicologically relevant. The emission of HCN and NH(3) were less than expected. Exposure assessment suggests that the exposure to NO(x) is the main health risk for the supporters that were present at the Euroborg fire. Copyright © 2010 Elsevier Ltd. All rights reserved.

Repeated Exposure to Conditioned Fear Stress Increases Anxiety and Delays Sleep Recovery Following Exposure to an Acute Traumatic Stressor

PubMed Central

Greenwood, Benjamin N.; Thompson, Robert S.; Opp, Mark R.; Fleshner, Monika

2014-01-01

Repeated stressor exposure can sensitize physiological responses to novel stressors and facilitate the development of stress-related psychiatric disorders including anxiety. Disruptions in diurnal rhythms of sleep–wake behavior accompany stress-related psychiatric disorders and could contribute to their development. Complex stressors that include fear-eliciting stimuli can be a component of repeated stress experienced by human beings, but whether exposure to repeated fear can prime the development of anxiety and sleep disturbances is unknown. In the current study, adult male F344 rats were exposed to either control conditions or repeated contextual fear conditioning for 22 days followed by exposure to no, mild (10), or severe (100) acute uncontrollable tail shock stress. Exposure to acute stress produced anxiety-like behavior as measured by a reduction in juvenile social exploration and exaggerated shock-elicited freezing in a novel context. Prior exposure to repeated fear enhanced anxiety-like behavior as measured by shock-elicited freezing, but did not alter social exploratory behavior. The potentiation of anxiety produced by prior repeated fear was temporary; exaggerated fear was present 1 day but not 4 days following acute stress. Interestingly, exposure to acute stress reduced rapid eye movement (REM) and non-REM (NREM) sleep during the hours immediately following acute stress. This initial reduction in sleep was followed by robust REM rebound and diurnal rhythm flattening of sleep/wake behavior. Prior repeated fear extended the acute stress-induced REM and NREM sleep loss, impaired REM rebound, and prolonged the flattening of the diurnal rhythm of NREM sleep following acute stressor exposure. These data suggest that impaired recovery of sleep/wake behavior following acute stress could contribute to the mechanisms by which a history of prior repeated stress increases vulnerability to subsequent novel stressors and stress-related disorders. PMID

Post-Extinction Conditional Stimulus Valence Predicts Reinstatement Fear: Relevance for Long Term Outcomes of Exposure Therapy

PubMed Central

Zbozinek, Tomislav D.; Hermans, Dirk; Prenoveau, Jason M.; Liao, Betty; Craske, Michelle G.

2014-01-01

Exposure therapy for anxiety disorders is translated from fear conditioning and extinction. While exposure therapy is effective in treating anxiety, fear sometimes returns after exposure. One pathway for return of fear is reinstatement: unsignaled unconditional stimuli following completion of extinction. The present study investigated the extent to which valence of the conditional stimulus (CS+) after extinction predicts return of CS+ fear after reinstatement. Participants (N = 84) engaged in a differential fear conditioning paradigm and were randomized to reinstatement or non-reinstatement. We hypothesized that more negative post-extinction CS+ valence would predict higher CS+ fear after reinstatement relative to non-reinstatement and relative to extinction retest. Results supported the hypotheses and suggest that strategies designed to decrease negative valence of the CS+ may reduce the return of fear via reinstatement following exposure therapy. PMID:24957680

Sex and Adolescent Ethanol Exposure Influence Pavlovian Conditioned Approach.

PubMed

Madayag, Aric C; Stringfield, Sierra J; Reissner, Kathryn J; Boettiger, Charlotte A; Robinson, Donita L

2017-04-01

Alcohol use among adolescents is widespread and a growing concern due to long-term behavioral deficits, including altered Pavlovian behavior, that potentially contribute to addiction vulnerability. We tested the hypothesis that adolescent intermittent ethanol (AIE) exposure alters Pavlovian behavior in males and females as measured by a shift from goal-tracking to sign-tracking. Additionally, we investigated GLT-1, an astrocytic glutamate transporter, as a potential contributor to a sign-tracking phenotype. Male and female Sprague-Dawley rats were exposed to AIE (5 g/kg, intragastric) or water intermittently 2 days on and 2 days off from postnatal day (P) 25 to 54. Around P70, animals began 20 daily sessions of Pavlovian conditioned approach (PCA), where they learned that a cue predicted noncontingent reward delivery. Lever pressing indicated interaction with the cue, or sign-tracking, and receptacle entries indicated approach to the reward delivery location, or goal-tracking. To test for effects of AIE on nucleus accumbens (NAcc) excitatory signaling, we isolated membrane subfractions and measured protein levels of the glutamate transporter GLT-1 after animals completed behavior as a measure of glutamate homeostasis. Females exhibited elevated sign-tracking compared to males with significantly more lever presses, faster latency to first lever press, and greater probability to lever press in a trial. AIE significantly increased lever pressing while blunting goal-tracking, as indicated by fewer cue-evoked receptacle entries, slower latency to receptacle entry, and lower probability to enter the receptacle in a trial. No significant sex-by-exposure interactions were observed in sign- or goal-tracking metrics. Moreover, we found no significant effects of sex or exposure on membrane GLT-1 expression in the NAcc. Females exhibited enhanced sign-tracking compared to males, while AIE decreased goal-tracking compared to control exposure. Our findings support the

Protocol for an HTA report: Does therapeutic writing help people with long-term conditions? Systematic review, realist synthesis and economic modelling.

PubMed

Meads, C; Nyssen, O P; Wong, G; Steed, L; Bourke, L; Ross, C A; Hayman, S; Field, V; Lord, J; Greenhalgh, T; Taylor, S J C

2014-02-18

Long-term medical conditions (LTCs) cause reduced health-related quality of life and considerable health service expenditure. Writing therapy has potential to improve physical and mental health in people with LTCs, but its effectiveness is not established. This project aims to establish the clinical and cost-effectiveness of therapeutic writing in LTCs by systematic review and economic evaluation, and to evaluate context and mechanisms by which it might work, through realist synthesis. Included are any comparative study of therapeutic writing compared with no writing, waiting list, attention control or placebo writing in patients with any diagnosed LTCs that report at least one of the following: relevant clinical outcomes; quality of life; health service use; psychological, behavioural or social functioning; adherence or adverse events. Searches will be conducted in the main medical databases including MEDLINE, EMBASE, PsycINFO, The Cochrane Library and Science Citation Index. For the realist review, further purposive and iterative searches through snowballing techniques will be undertaken. Inclusions, data extraction and quality assessment will be in duplicate with disagreements resolved through discussion. Quality assessment will include using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. Data synthesis will be narrative and tabular with meta-analysis where appropriate. De novo economic modelling will be attempted in one clinical area if sufficient evidence is available and performed according to the National Institute for Health and Care Excellence (NICE) reference case.

Consequences of ethanol exposure on cued and contextual fear conditioning and extinction in adulthood differ depending on timing of exposure

PubMed Central

Broadwater, Margaret; Spear, Linda P.

2013-01-01

Some evidence suggests that adolescents are more sensitive than adults to ethanol-induced cognitive deficits and that these effects may be long-lasting. The purpose of Exp 1 was to determine if early-mid adolescent [Postnatal day (P) 28-48] intermittent ethanol exposure would affect later learning and memory in a Pavlovian fear conditioning paradigm differently than comparable exposures in adulthood (P70-90). In Exp 2 animals were exposed to ethanol during mid-late adolescence (P35-55) to assess whether age of initiation within the adolescent period would influence learning and memory differentially. Male Sprague-Dawley rats were given 4 g/kg i.g. ethanol (25%) or water every 48 hours for a total of 11 exposures. After a 22 day non-ethanol period, animals were fear conditioned to a context (relatively hippocampal-dependent task) or tone (amygdala-dependent task), followed by retention tests and extinction (mPFC-dependent) of this conditioning. Despite similar acquisition, a deficit in context fear retention was evident in animals exposed to ethanol in early adolescence, an effect not observed after a comparable ethanol exposure in mid-late adolescence or adulthood. In contrast, animals that were exposed to ethanol in mid-late adolescence or adulthood showed enhanced resistance to context extinction. Together these findings suggest that repeated ethanol imparts long-lasting consequences on learning and memory, with outcomes that differ depending on age of exposure. These results may reflect differential influence of ethanol on the brain as it changes throughout ontogeny and may have implications for alcohol use not only throughout the developmental period of adolescence, but also in adulthood. PMID:23938333

[Occupational differences in exposure to hazardous work conditions].

PubMed

Marinacci, Chiara; d'Errico, A; Cardano, M; Perini, F; Costa, G

2005-01-01

Few studies have been aimed at describing organizational and psychosocial conditions of the Italian workforce by occupational group, and they have been mainly conducted within specific occupations. The present study aimed at identifying specific groups of occupations which have unfavourable profiles from the point of view of exposure to specific organizational factors and psychosocial risks, and to physical, chemical and ergonomic risks, and analyzing their distribution by worker age. The analysis was conducted on a sample of 4,195 workers in the Piedmont Region who were members of the CGIL Trade Union (Italian General Confederation of Labour), who answered a self-administered questionnaire in 2000, aimed at assessing chemical, physical, and ergonomic risks, accidents, and psychosocial factors connected with work organization and work tasks. Psychosocial risks were assessed via three scales aimed at measuring the degree of control, psychophysical demands, and worker satisfaction. The proportion of workers exposed to the above mentioned risks was analysed according to occupational group. This group was then compared with all other groups taken together, according to prevalence of high strain condition (combination of high demand and low control) and HSUR condition (High Strain Unfairly Rewarded; combination of high strain and low satisfaction). Among males aged 25-44 years, restricted to the occupation groups with more than ten workers in high strain condition, significantly higher proportions of stress were observed in leather workers and shoemakers, paper factory workers, rubber workers, crane and bridge crane operators, plastic workers, painters, transport drivers and carpenters. For many of these groups, excesses were confirmed for the HSUR condition. Among subjects aged over 44 years, a higher risk for high strain was confirmed in rubber workers, transport drivers and carpenters. In addition, machine tool operators, assembly line and mechanical workers in this

Toxicity effects of an environmental realistic herbicide mixture on the seagrass Zostera noltei.

PubMed

Diepens, Noël J; Buffan-Dubau, Evelyne; Budzinski, Hélène; Kallerhoff, Jean; Merlina, Georges; Silvestre, Jérome; Auby, Isabelle; Nathalie Tapie; Elger, Arnaud

2017-03-01

Worldwide seagrass declines have been observed due to multiple stressors. One of them is the mixture of pesticides used in intensive agriculture and boat antifouling paints in coastal areas. Effects of mixture toxicity are complex and poorly understood. However, consideration of mixture toxicity is more realistic and ecologically relevant for environmental risk assessment (ERA). The first aim of this study was to determine short-term effects of realistic herbicide mixture exposure on physiological endpoints of Zostera noltei. The second aim was to assess the environmental risks of this mixture, by comparing the results to previously published data. Z. noltei was exposed to a mixture of four herbicides: atrazine, diuron, irgarol and S-metolachlor, simulating the composition of typical cocktail of contaminants in the Arcachon bay (Atlantic coast, France). Three stress biomarkers were measured: enzymatic activity of glutathione reductase, effective quantum yield (EQY) and photosynthetic pigment composition after 6, 24 and 96 h. Short term exposure to realistic herbicide mixtures affected EQY, with almost 100% inhibition for the two highest concentrations, and photosynthetic pigments. Effect on pigment composition was detected after 6 h with a no observed effect concentration (NOEC) of 1 μg/L total mixture concentration. The lowest EQY effect concentration at 10% (EC 10 ) (2 μg/L) and pigment composition NOEC with an assessment factor of 10 were above the maximal field concentrations along the French Atlantic coast, suggesting that there are no potential short term adverse effects of this particular mixture on Z. noltei. However, chronic effects on photosynthesis may lead to reduced energy reserves, which could thus lead to effects at whole plant and population level. Understanding the consequences of chemical mixtures could help to improve ERA and enhance management strategies to prevent further declines of seagrass meadows worldwide. Copyright © 2016

Exposure to Novelty Weakens Conditioned Fear in Long-Evans Rats

ERIC Educational Resources Information Center

Anderson, Matthew J.; Burpee, Tara E.; Wall, Matthew J.; McGraw, Justin J.

2013-01-01

The present study sought to determine whether post-training exposure to a novel or familiar object, encountered in either the location of the original fear conditioning (black compartment of a passive avoidance {PA} chamber) or in a neutral setting (open field where initial object training had occurred) would prove capable of reducing fear at…

Realistic Control Perceptions, Age, and Gender as Moderators of the Relationship between Victimization and Hope in Children.

ERIC Educational Resources Information Center

Oskin, Deborah L.

This study examined age, gender, and subjects' realistic perceptions of control as potential moderators of the effect of community violence exposure (victimization and witnessing) on children's hopes for the future. Home interviews were conducted with 99 children ages 8 to 12 years living in high violence areas of a large southeastern city.…

Consequences of adolescent ethanol exposure in male Sprague-Dawley rats on fear conditioning and extinction in adulthood

NASA Astrophysics Data System (ADS)

Broadwater, Margaret A.

Some evidence suggests that adolescents are more vulnerable than adults to alcohol-induced cognitive deficits and that these deficits may persist into adulthood. Five experiments were conducted to assess long-term consequences of ethanol exposure on tone and context Pavlovian fear conditioning in male Sprague-Dawley rats. Experiment 1 examined age-related differences in sensitivity to ethanol-induced disruptions of fear conditioning to a pre-conditioning ethanol challenge. Experiments 2 examined fear conditioning 22 days after early-mid adolescent (P28-48) or adult (P70-90) exposure to 4 g/kg i.g. ethanol or water given every other day (total of 11 exposures). In Experiment 3, mid-late adolescents (P35-55) were exposed in the same manner to assess whether timing of ethanol exposure within the adolescent period would differentially affect later fear conditioning. Experiment 4 assessed the influence of prior adolescent or adult ethanol exposure on the disrupting effects of a pre-conditioning ethanol challenge. In Experiment 5, neurogenesis (doublecortin---DCX) and cholinergic (choline acetyltransferase---ChAT) markers were measured to assess potential long-term ethanol-induced changes in neural mechanisms important for learning and memory. Results indicated that the long-lasting behavioral effects of ethanol exposure varied depending on exposure age, with early-mid adolescent exposed animals showing attenuated context fear retention (a relatively hippocampal-dependent task), whereas mid-late adolescent and adult exposed animals showed slower context extinction (thought to be reliant on the mPFC). Early-mid adolescent ethanol-exposed animals also had significantly less DCX and ChAT expression than their water-exposed counterparts, possibly contributing to deficits in context fear. Tone fear was not influenced by prior ethanol exposure at any age. In terms of age differences in ethanol sensitivity, adolescents were less sensitive than adults to ethanol

Metallothionein-Like Proteins and Energy Reserve Levels after Ni and Pb Exposure in the Pacific White Prawn Penaeus vannamei

PubMed Central

Nunez-Nogueira, Gabriel; Mouneyrac, Catherine; Muntz, Alice; Fernandez-Bringas, Laura

2010-01-01

This study analyzed the changes in metallothionein-like proteins (MTLPs) and Energy Reserves (ERs) in hepatopancreas and abdominal muscle of the white prawn Penaeus vannamei. Realistic metal concentration exposure for 10 days to Ni and Pb in solution revealed that juvenile prawns partially induce MTLP in hepatopancreas after Pb exposure. Ni was distributed equally between soluble and insoluble fractions, while Pb was present only in the insoluble fraction, suggesting different detoxification strategy. No changes in lipids and glycogen concentration were detected under these experimental conditions in both tissues analyzed. MTLP could not be considered as a suitable indicator for lead exposure in hepatopancreas. PMID:20862200

A critical review of perfluorooctanoate and perfluorooctanesulfonate exposure and immunological health conditions in humans

PubMed Central

Chang, Ellen T.; Adami, Hans-Olov; Boffetta, Paolo; Wedner, H. James; Mandel, Jack S.

2016-01-01

Abstract Whether perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS), two widely used and biopersistent synthetic chemicals, are immunotoxic in humans is unclear. Accordingly, this article systematically and critically reviews the epidemiologic evidence on the association between exposure to PFOA and PFOS and various immune-related health conditions in humans. Twenty-four epidemiologic studies have reported associations of PFOA and/or PFOS with immune-related health conditions, including ten studies of immune biomarker levels or gene expression patterns, ten studies of atopic or allergic disorders, five studies of infectious diseases, four studies of vaccine responses, and five studies of chronic inflammatory or autoimmune conditions (with several studies evaluating multiple endpoints). Asthma, the most commonly studied condition, was evaluated in seven studies. With few, often methodologically limited studies of any particular health condition, generally inconsistent results, and an inability to exclude confounding, bias, or chance as an explanation for observed associations, the available epidemiologic evidence is insufficient to reach a conclusion about a causal relationship between exposure to PFOA and PFOS and any immune-related health condition in humans. When interpreting such studies, an immunodeficiency should not be presumed to exist when there is no evidence of a clinical abnormality. Large, prospective studies with repeated exposure assessment in independent populations are needed to confirm some suggestive associations with certain endpoints. PMID:26761418

Exposure to conditions of uncertainty promotes the pursuit of amphetamine.

PubMed

Mascia, Paola; Neugebauer, Nichole M; Brown, Jason; Bubula, Nancy; Nesbitt, Kathryn M; Kennedy, Robert T; Vezina, Paul

2018-05-22

Prior exposure to abused drugs leads to long-lasting neuroadaptations culminating in excessive drug intake. Given the comorbidity between substance use and gambling disorders, surprisingly little is known about the effects of exposure to reinforcement contingencies experienced during games of chance. As it is a central feature of these games, we characterized the effects of exposure to uncertainty on biochemical and behavioral effects normally observed in rats exposed to amphetamine. Rats in different groups were trained to nose-poke for saccharin under certain [fixed-ratio (FR)] or uncertain conditions [variable-ratio (VR)] for 55 1-h sessions. Ratios were escalated on successive sessions and rats maintained on the last ratio (FR/VR 20) for 20-25 days. Two to three weeks later, rats were tested for their locomotor or nucleus accumbens dopamine (NAcc DA) response to amphetamine or self-administration of the drug using a lever press operant. NAcc DA overflow was also assessed in additional rats during the saccharin sessions. Rats exposed to uncertainty subsequently showed a higher locomotor and NAcc DA response to amphetamine and self-administered more drug infusions relative to rats exposed to predictable reinforcement. NAcc DA levels during the saccharin sessions tracked the variance of the scheduled ratios (a measure of uncertainty). VR rats showed escalating DA overflow with increasing ratios. Exposure to uncertainty triggered neuroadaptations similar to those produced by exposure to abused drugs. As these were produced in drug naive rats both during and after exposure to uncertainty, they provide a novel common pathway to drug and behavioral addictions.

Cadmium uptake and toxicity to water hyacinth: Effect of repeated exposures under controlled conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nir, R.; Gasith, A.; Perry, A.S.

1990-01-01

Water hyacinth, Eichornia crassipes has drawn attention as a plant of rapid growth and high biomass production, and capable of removing pollutants from domestic and industrial waste effluents. Most of the studies were static assays of short duration (1 to 3 days) and with a single exposure of the plants to cadmium. The authors presumed that repeated exposures to Cd might change the rate of uptake of the metal as well as the growth and physiological state of the plant. This prompted us to undertake the present study in order to evaluate the potential capacity of water hyacinth to removemore » Cd from solution under conditions of repeated exposures but otherwise favorable growth conditions and without interference from other toxic compounds. Removal of metal from effluents by plants is expected to be compounded by the influence of specific conditions of the medium such as temperature, pH, ionic strength, presence of other metals or complexing ligands. The results of the present study will serve as a comparative reference for evaluating the effect of effluent conditions on CD toxicity to water hyacinth and the plant's capacity for metal removal.« less

Embryonic Methamphetamine Exposure Inhibits Methamphetamine Cue Conditioning and Reduces Dopamine Concentrations in Adult N2 C. elegans

PubMed Central

Katner, S.N.; Neal-Beliveau, B.S.; Engleman, E.A.

2016-01-01

Methamphetamine (MAP) addiction is substantially prevalent in today's society, resulting in thousands of deaths and costing billions of dollars annually. Despite the potential deleterious consequences, few studies have examined the long-term effects of embryonic MAP exposure. Using the invertebrate nematode Caenorhabditis elegans (C. elegans) allows for a controlled analysis of behavioral and neurochemical changes due to early developmental drug exposure. The objective of the current studies was to determine the long-term behavioral and neurochemical effects of embryonic exposure to MAP in C. elegans. In addition, we sought to improve our conditioning and testing procedures by utilizing liquid filtration, as opposed to agar, and smaller, 6-well testing plates to increase throughput. Wild-type N2 C. elegans were embryonically exposed to 50 μM MAP. Using classical conditioning, adult-stage C. elegans were conditioned to MAP (17 and 500 μM) in the presence of either sodium ions (Na+) or chloride (Cl-) ions as conditioned stimuli (CS+/CS-). Following conditioning, a preference test was performed by placing worms in 6-well test plates spotted with the CS+ and CS- at opposite ends of each well. A preference index (PI) was determined by counting the number of worms in the CS+ target zone divided by the total number of worms in the CS+ and CS- target zones. A food conditioning experiment was also performed in order to determine if embryonic MAP exposure affected food conditioning behavior. For the neurochemical experiments, adult worms that were embryonically exposed to MAP were analyzed for (dopamine) DA content using high performance liquid chromatography (HPLC). The liquid filtration conditioning procedure employed here in combination with the use 6-well test plates significantly decreased the time required to perform these experiments and ultimately increased throughput. The MAP conditioning data found that pairing an ion with MAP at 17 or 500 μM significantly

Embryonic Methamphetamine Exposure Inhibits Methamphetamine Cue Conditioning and Reduces Dopamine Concentrations in Adult N2 Caenorhabditis elegans.

PubMed

Katner, Simon N; Neal-Beliveau, Bethany S; Engleman, Eric A

2016-01-01

Methamphetamine (MAP) addiction is substantially prevalent in today's society, resulting in thousands of deaths and costing billions of dollars annually. Despite the potential deleterious consequences, few studies have examined the long-term effects of embryonic MAP exposure. Using the invertebrate nematode Caenorhabditis elegans allows for a controlled analysis of behavioral and neurochemical changes due to early developmental drug exposure. The objective of the current study was to determine the long-term behavioral and neurochemical effects of embryonic exposure to MAP in C. elegans. In addition, we sought to improve our conditioning and testing procedures by utilizing liquid filtration, as opposed to agar, and smaller, 6-well testing plates to increase throughput. Wild-type N2 C. elegans were embryonically exposed to 50 μM MAP. Using classical conditioning, adult-stage C. elegans were conditioned to MAP (17 and 500 μM) in the presence of either sodium ions (Na+) or chloride ions (Cl-) as conditioned stimuli (CS+/CS-). Following conditioning, a preference test was performed by placing worms in 6-well test plates spotted with the CS+ and CS- at opposite ends of each well. A preference index was determined by counting the number of worms in the CS+ target zone divided by the total number of worms in the CS+ and CS- target zones. A food conditioning experiment was also performed in order to determine whether embryonic MAP exposure affected food conditioning behavior. For the neurochemical experiments, adult worms that were embryonically exposed to MAP were analyzed for dopamine (DA) content using high-performance liquid chromatography. The liquid filtration conditioning procedure employed here in combination with the use of 6-well test plates significantly decreased the time required to perform these experiments and ultimately increased throughput. The MAP conditioning data found that pairing an ion with MAP at 17 or 500 μM significantly increased the preference

Protocol for an HTA report: Does therapeutic writing help people with long-term conditions? Systematic review, realist synthesis and economic modelling

PubMed Central

Meads, C; Nyssen, O P; Wong, G; Steed, L; Bourke, L; Ross, C A; Hayman, S; Field, V; Lord, J; Greenhalgh, T; Taylor, S J C

2014-01-01

Introduction Long-term medical conditions (LTCs) cause reduced health-related quality of life and considerable health service expenditure. Writing therapy has potential to improve physical and mental health in people with LTCs, but its effectiveness is not established. This project aims to establish the clinical and cost-effectiveness of therapeutic writing in LTCs by systematic review and economic evaluation, and to evaluate context and mechanisms by which it might work, through realist synthesis. Methods Included are any comparative study of therapeutic writing compared with no writing, waiting list, attention control or placebo writing in patients with any diagnosed LTCs that report at least one of the following: relevant clinical outcomes; quality of life; health service use; psychological, behavioural or social functioning; adherence or adverse events. Searches will be conducted in the main medical databases including MEDLINE, EMBASE, PsycINFO, The Cochrane Library and Science Citation Index. For the realist review, further purposive and iterative searches through snowballing techniques will be undertaken. Inclusions, data extraction and quality assessment will be in duplicate with disagreements resolved through discussion. Quality assessment will include using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. Data synthesis will be narrative and tabular with meta-analysis where appropriate. De novo economic modelling will be attempted in one clinical area if sufficient evidence is available and performed according to the National Institute for Health and Care Excellence (NICE) reference case. PMID:24549165

A DYNAMIC NONLINEAR MODEL OF OZONE-INDUCED FEV1 RESPONSE UNDER CHANGING EXPOSURE CONDITIONS

EPA Science Inventory

A Dynamic Nonlinear Model of Ozone-induced FEV1 Response under Changing Exposure Conditions. 1WF McDonnell, 2PW Stewart, 3MV Smith. 1Human Studies Division, NHEERL, U.S. EPA, RTP, NC. 2University of North Carolina, Chapel Hill, NC. 3ASI, Durham, NC.

Ozone exposure result...

A realist evaluation of the management of a well- performing regional hospital in Ghana

PubMed Central

2010-01-01

Background Realist evaluation offers an interesting approach to evaluation of interventions in complex settings, but has been little applied in health care. We report on a realist case study of a well performing hospital in Ghana and show how such a realist evaluation design can help to overcome the limited external validity of a traditional case study. Methods We developed a realist evaluation framework for hypothesis formulation, data collection, data analysis and synthesis of the findings. Focusing on the role of human resource management in hospital performance, we formulated our hypothesis around the high commitment management concept. Mixed methods were used in data collection, including individual and group interviews, observations and document reviews. Results We found that the human resource management approach (the actual intervention) included induction of new staff, training and personal development, good communication and information sharing, and decentralised decision-making. We identified 3 additional practices: ensuring optimal physical working conditions, access to top managers and managers' involvement on the work floor. Teamwork, recognition and trust emerged as key elements of the organisational climate. Interviewees reported high levels of organisational commitment. The analysis unearthed perceived organisational support and reciprocity as underlying mechanisms that link the management practices with commitment. Methodologically, we found that realist evaluation can be fruitfully used to develop detailed case studies that analyse how management interventions work and in which conditions. Analysing the links between intervention, mechanism and outcome increases the explaining power, while identification of essential context elements improves the usefulness of the findings for decision-makers in other settings (external validity). We also identified a number of practical difficulties and priorities for further methodological development

A realist evaluation of the management of a well-performing regional hospital in Ghana.

PubMed

Marchal, Bruno; Dedzo, McDamien; Kegels, Guy

2010-01-25

Realist evaluation offers an interesting approach to evaluation of interventions in complex settings, but has been little applied in health care. We report on a realist case study of a well performing hospital in Ghana and show how such a realist evaluation design can help to overcome the limited external validity of a traditional case study. We developed a realist evaluation framework for hypothesis formulation, data collection, data analysis and synthesis of the findings. Focusing on the role of human resource management in hospital performance, we formulated our hypothesis around the high commitment management concept. Mixed methods were used in data collection, including individual and group interviews, observations and document reviews. We found that the human resource management approach (the actual intervention) included induction of new staff, training and personal development, good communication and information sharing, and decentralised decision-making. We identified 3 additional practices: ensuring optimal physical working conditions, access to top managers and managers' involvement on the work floor. Teamwork, recognition and trust emerged as key elements of the organisational climate. Interviewees reported high levels of organisational commitment. The analysis unearthed perceived organisational support and reciprocity as underlying mechanisms that link the management practices with commitment. Methodologically, we found that realist evaluation can be fruitfully used to develop detailed case studies that analyse how management interventions work and in which conditions. Analysing the links between intervention, mechanism and outcome increases the explaining power, while identification of essential context elements improves the usefulness of the findings for decision-makers in other settings (external validity). We also identified a number of practical difficulties and priorities for further methodological development. This case suggests that a well

29 CFR Appendix A to Subpart Y of... - Examples of Conditions Which May Restrict or Limit Exposure to Hyperbaric Conditions

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 8 2010-07-01 2010-07-01 false Examples of Conditions Which May Restrict or Limit Exposure to Hyperbaric Conditions A Appendix A to Subpart Y of Part 1926 Labor Regulations Relating to Labor... REGULATIONS FOR CONSTRUCTION Diving Pt. 1926, Subpt. Y, App. A Appendix A to Subpart Y of Part 1926—Examples...

The effect of post-conditioning exposure to morphine on the retention of a morphine-induced conditioned taste aversion.

PubMed

Jacobs, W J; Zellner, D A; LoLordo, V M; Riley, A L

1981-06-01

In the following experiment, multiple injections of morphine sulfate following the acquisition of a morphine-induced taste aversion had no effect on the retention of the previously acquired aversion. Post-conditioning injections of morphine resulted in the development of physical dependence to morphine and led to a decrement in the ability of morphine to induce a subsequent aversion to a second novel taste. This failure of post-conditioning exposures to morphine to affect a previously acquired morphine-induced taste aversion even though tolerance to morphine had occurred was discussed in the context of Rescorla's event-memory model of conditioning.

Hydroquinone PBPK model refinement and application to dermal exposure.

PubMed

Poet, Torka S; Carlton, Betsy D; Deyo, James A; Hinderliter, Paul M

2010-11-01

A physiologically based pharmacokinetic (PBPK) model for hydroquinone (HQ) was refined to include an expanded description of HQ-glucuronide metabolites and a description of dermal exposures to support route-to-route and cross-species extrapolation. Total urinary excretion of metabolites from in vivo rat dermal exposures was used to estimate a percutaneous permeability coefficient (K(p); 3.6×10(-5) cm/h). The human in vivo K(p) was estimated to be 1.62×10(-4) cm/h, based on in vitro skin permeability data in rats and humans and rat in vivo values. The projected total multi-substituted glutathione (which was used as an internal dose surrogate for the toxic glutathione metabolites) was modeled following an exposure scenario based on submersion of both hands in a 5% aqueous solution of HQ (similar to black and white photographic developing solution) for 2 h, a worst-case exposure scenario. Total multi-substituted glutathione following this human dermal exposure scenario was several orders of magnitude lower than the internal total glutathione conjugates in rats following an oral exposure to the rat NOEL of 20 mg/kg. Thus, under more realistic human dermal exposure conditions, it is unlikely that toxic glutathione conjugates (primarily the di- and, to a lesser degree, the tri-glutathione conjugate) will reach significant levels in target tissues. Copyright © 2010. Published by Elsevier Ltd.

CONSEQUENCES OF REPEATED ETHANOL EXPOSURE DURING EARLY OR LATE ADOLESCENCE ON CONDITIONED TASTE AVERSIONS IN RATS

PubMed Central

Saalfield, Jessica; Spear, Linda

2015-01-01

Alcohol use is prevalent during adolescence, yet little is known about possible long-lasting consequences.. Recent evidence suggests that adolescents are less sensitive than adults to ethanol’s aversive effects, an insensitivity that may be retained into adulthood after repeated adolescent ethanol exposure. This study assessed whether intermittent ethanol exposure during early or late adolescence (early-AIE or late-AIE, respectively) would affect ethanol conditioned taste aversions 2 days (CTA1) and >3 weeks (CTA2) post-exposure using supersaccharin and saline as conditioning stimuli (CS), respectively. Pair-housed male Sprague-Dawley rats received 4 g/kg i.g. ethanol (25%) or water every 48 hours from postnatal day (P) 25–45 (early AIE) or P45–65 (late AIE), or were left non-manipulated (NM). During conditioning, 30 min home cage access to the CS was followed by 0, 1, 1.5, 2 or 2.5 g/kg ethanol i.p., with testing 2 days later. Attenuated CTA relative to controls was seen among early and late AIE animals at both CTA1 and CTA2, an effect particularly pronounced at CTA1 after late AIE. Thus, adolescent exposure to ethanol was found to induce an insensitivity to ethanol CTA seen soon after exposure and lasting into adulthood, and evident with ethanol exposures not only early but also later in adolescence. PMID:25698309

The Role of Exposure Condition in the Effectiveness of Explicit Correction

ERIC Educational Resources Information Center

Yilmaz, Yucel

2016-01-01

This article reports on a study that investigated the effects of two feedback exposure conditions on the acquisition of two Turkish morphemes. The study followed a randomized experimental design with an immediate and a delayed posttest. Forty-two Chinese-speaking learners of Turkish were randomly assigned to one of three groups: receivers,…

IMPORTANT EXPOSURE FACTORS FOR CHILDREN AN ANALYSIS OF LABORATORY AND OBSERVATIONAL FIELD DATA CHARACTERIZING CUMULATIVE EXPOSURE TO PESTICIDES

EPA Science Inventory

In an effort to facilitate more realistic risk assessments that take into account unique childhood vulnerabilities to environmental toxicants, the U.S. EPA's National Exposure Research Laboratory (NERL) developed a framework for systematically identifying and addressing the most ...

Downscaling Ocean Conditions: Initial Results using a Quasigeostrophic and Realistic Ocean Model

NASA Astrophysics Data System (ADS)

Katavouta, Anna; Thompson, Keith

2014-05-01

Previous theoretical work (Henshaw et al, 2003) has shown that the small-scale modes of variability of solutions of the unforced, incompressible Navier-Stokes equation, and Burgers' equation, can be reconstructed with surprisingly high accuracy from the time history of a few of the large-scale modes. Motivated by this theoretical work we first describe a straightforward method for assimilating information on the large scales in order to recover the small scale oceanic variability. The method is based on nudging in specific wavebands and frequencies and is similar to the so-called spectral nudging method that has been used successfully for atmospheric downscaling with limited area models (e.g. von Storch et al., 2000). The validity of the method is tested using a quasigestrophic model configured to simulate a double ocean gyre separated by an unstable mid-ocean jet. It is shown that important features of the ocean circulation including the position of the meandering mid-ocean jet and associated pinch-off eddies can indeed be recovered from the time history of a small number of large-scales modes. The benefit of assimilating additional time series of observations from a limited number of locations, that alone are too sparse to significantly improve the recovery of the small scales using traditional assimilation techniques, is also demonstrated using several twin experiments. The final part of the study outlines the application of the approach using a realistic high resolution (1/36 degree) model, based on the NEMO (Nucleus for European Modelling of the Ocean) modeling framework, configured for the Scotian Shelf of the east coast of Canada. The large scale conditions used in this application are obtained from the HYCOM (HYbrid Coordinate Ocean Model) + NCODA (Navy Coupled Ocean Data Assimilation) global 1/12 degree analysis product. Henshaw, W., Kreiss, H.-O., Ystrom, J., 2003. Numerical experiments on the interaction between the larger- and the small-scale motion of

A realistic evaluation: the case of protocol-based care

PubMed Central

2010-01-01

Background 'Protocol based care' was envisioned by policy makers as a mechanism for delivering on the service improvement agenda in England. Realistic evaluation is an increasingly popular approach, but few published examples exist, particularly in implementation research. To fill this gap, within this paper we describe the application of a realistic evaluation approach to the study of protocol-based care, whilst sharing findings of relevance about standardising care through the use of protocols, guidelines, and pathways. Methods Situated between positivism and relativism, realistic evaluation is concerned with the identification of underlying causal mechanisms, how they work, and under what conditions. Fundamentally it focuses attention on finding out what works, for whom, how, and in what circumstances. Results In this research, we were interested in understanding the relationships between the type and nature of particular approaches to protocol-based care (mechanisms), within different clinical settings (context), and what impacts this resulted in (outcomes). An evidence review using the principles of realist synthesis resulted in a number of propositions, i.e., context, mechanism, and outcome threads (CMOs). These propositions were then 'tested' through multiple case studies, using multiple methods including non-participant observation, interviews, and document analysis through an iterative analysis process. The initial propositions (conjectured CMOs) only partially corresponded to the findings that emerged during analysis. From the iterative analysis process of scrutinising mechanisms, context, and outcomes we were able to draw out some theoretically generalisable features about what works, for whom, how, and what circumstances in relation to the use of standardised care approaches (refined CMOs). Conclusions As one of the first studies to apply realistic evaluation in implementation research, it was a good fit, particularly given the growing emphasis on

Improvement in Simulation of Eurasian Winter Climate Variability with a Realistic Arctic Sea Ice Condition in an Atmospheric GCM

NASA Technical Reports Server (NTRS)

Lim, Young-Kwon; Ham, Yoo-Geun; Jeong, Jee-Hoon; Kug, Jong-Seong

2012-01-01

The present study investigates how much a realistic Arctic sea ice condition can contribute to improve simulation of the winter climate variation over the Eurasia region. Model experiments are set up using different sea ice boundary conditions over the past 24 years (i.e., 1988-2011). One is an atmospheric model inter-comparison (AMIP) type of run forced with observed sea-surface temperature (SST), sea ice, and greenhouse gases (referred to as Exp RSI), and the other is the same as Exp RSI except for the sea ice forcing, which is a repeating climatological annual cycle (referred to as Exp CSI). Results show that Exp RSI produces the observed dominant pattern of Eurasian winter temperatures and their interannual variation better than Exp CSI (correlation difference up to approx. 0.3). Exp RSI captures the observed strong relationship between the sea ice concentration near the Barents and Kara seas and the temperature anomaly across Eurasia, including northeastern Asia, which is not well captured in Exp CSI. Lagged atmospheric responses to sea ice retreat are examined using observations to understand atmospheric processes for the Eurasian cooling response including the Arctic temperature increase, sea-level pressure increase, upper-level jet weakening and cold air outbreak toward the mid-latitude. The reproducibility of these lagged responses by Exp RSI is also evaluated.

Consequences of repeated ethanol exposure during early or late adolescence on conditioned taste aversions in rats.

PubMed

Saalfield, Jessica; Spear, Linda

2015-12-01

Alcohol use is prevalent during adolescence, yet little is known about possible long-lasting consequences. Recent evidence suggests that adolescents are less sensitive than adults to ethanol's aversive effects, an insensitivity that may be retained into adulthood after repeated adolescent ethanol exposure. This study assessed whether intermittent ethanol exposure during early or late adolescence (early-AIE or late-AIE, respectively) would affect ethanol conditioned taste aversions 2 days (CTA1) and >3 weeks (CTA2) post-exposure using supersaccharin and saline as conditioning stimuli (CS), respectively. Pair-housed male Sprague-Dawley rats received 4g/kg i.g. ethanol (25%) or water every 48 h from postnatal day (P) 25-45 (early AIE) or P45-65 (late AIE), or were left non-manipulated (NM). During conditioning, 30 min home cage access to the CS was followed by 0, 1, 1.5, 2 or 2.5g/kg ethanol i.p., with testing 2 days later. Attenuated CTA relative to controls was seen among early and late AIE animals at both CTA1 and CTA2, an effect particularly pronounced at CTA1 after late AIE. Thus, adolescent exposure to ethanol was found to induce an insensitivity to ethanol CTA seen soon after exposure and lasting into adulthood, and evident with ethanol exposures not only early but also later in adolescence. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Realistic Clocks for a Universe Without Time

NASA Astrophysics Data System (ADS)

Bryan, K. L. H.; Medved, A. J. M.

2018-01-01

There are a number of problematic features within the current treatment of time in physical theories, including the "timelessness" of the Universe as encapsulated by the Wheeler-DeWitt equation. This paper considers one particular investigation into resolving this issue; a conditional probability interpretation that was first proposed by Page and Wooters. Those authors addressed the apparent timelessness by subdividing a faux Universe into two entangled parts, "the clock" and "the remainder of the Universe", and then synchronizing the effective dynamics of the two subsystems by way of conditional probabilities. The current treatment focuses on the possibility of using a (somewhat) realistic clock system; namely, a coherent-state description of a damped harmonic oscillator. This clock proves to be consistent with the conditional probability interpretation; in particular, a standard evolution operator is identified with the position of the clock playing the role of time for the rest of the Universe. Restrictions on the damping factor are determined and, perhaps contrary to expectations, the optimal choice of clock is not necessarily one of minimal damping.

Simulated response and effects to oil exposure in an estuarine fish species

EPA Science Inventory

Experimental toxicity data alone lack ecological relevance to assess more realistic situations, such as variable exposure to a contaminant and long-term impact. Evaluating the implications of sublethal effects or behavioral response to exposure requires long-term, population-leve...

Hemograms for and nutritional condition of migrant bald eagles tested for exposure to lead.

PubMed

Miller, M J; Wayland, M E; Bortolotti, G R

2001-07-01

Plasma proteins, hematocrit, differential blood counts were examined and nutritional condition was estimated for bald eagles (Haliaeetus leucocephalus) trapped (n = 66) during antumn migration, 1994-95 at Galloway Bay (Saskatchewan, Canada), for the purposes of estimating prevalence of exposure to lead. Sex and age differences in hematocrit and plasma proteins were not observed; however, female eagles exhibited larger median absolute heterophil counts than males. Hematologic values were similar to those previously reported from eagles in captivity. Departures from expected hematological values from a healthy population of eagles were not observed in birds with elevated levels of blood lead (> or =0.200 microg/ml). Similarly, nutritional condition was not related to blood-lead concentrations. Therefore, it appears that lead exposure in this population was below a threshold required to indicate toxicological alteration in the hematological values and index of nutritional condition that we measured.

Exposure assessment of microwave ovens and impact on total exposure in WLANs

PubMed Central

Plets, David; Verloock, Leen; Van Den Bossche, Matthias; Tanghe, Emmeric; Joseph, Wout; Martens, Luc

2016-01-01

In situ exposure of electric fields of 11 microwave ovens is assessed in an occupational environment and in an office. Measurements as a function of distance without load and with a load of 275 ml of tap water were performed at distances of <1 m. The maximal measured field was 55.2 V m−1 at 5 cm from the oven (without load), which is 2.5 and 1.1 times below the International Commission on Non-Ionizing Radiation Protection reference level for occupational exposure and general public exposure, respectively. For exposure at distances of >1 m, a model of the electric field in a realistic environment is proposed. In an office scenario, switching on a microwave oven increases the median field strength from 91 to 145 mV m−1 (+91 %) in a traditional Wireless Local Area Network (WLAN) deployment and from 44 to 92 mV m−1 (+109 %) in an exposure-optimised WLAN deployment. PMID:25956787

FAULT TREE ANALYSIS FOR EXPOSURE TO REFRIGERANTS USED FOR AUTOMOTIVE AIR CONDITIONING IN THE U.S.

EPA Science Inventory

A fault tree analysis was used to estimate the number of refrigerant exposures of automotive service technicians and vehicle occupants in the United States. Exposures of service technicians can occur when service equipment or automotive air-conditioning systems leak during servic...

Review of Non-Respiratory, Non-Cancer Physical Health Conditions from Exposure to the World Trade Center Disaster

PubMed Central

Gargano, Lisa M.; Mantilla, Kimberly; Fairclough, Monique; Yu, Shengchao; Brackbill, Robert M.

2018-01-01

After the World Trade Center attacks on 11 September 2001 (9/11), multiple cohorts were developed to monitor the health outcomes of exposure. Respiratory and cancer effects have been covered at length. This current study sought to review the literature on other physical conditions associated with 9/11-exposure. Researchers searched seven databases for literature published in English from 2002 to October 2017, coded, and included articles for health condition outcome, population, 9/11-exposures, and comorbidity. Of the 322 titles and abstracts screened, 30 studies met inclusion criteria, and of these, 28 were from three cohorts: the World Trade Center Health Registry, Fire Department of New York, and World Trade Center Health Consortium. Most studies focused on rescue and recovery workers. While many of the findings were consistent across different populations and supported by objective measures, some of the less studied conditions need additional research to substantiate current findings. In the 16 years after 9/11, longitudinal cohorts have been essential in investigating the health consequences of 9/11-exposure. Longitudinal studies will be vital in furthering our understanding of these emerging conditions, as well as treatment effectiveness. PMID:29401643

Consumer exposure scenarios: development, challenges and possible solutions.

PubMed

Van Engelen, J G M; Heinemeyer, G; Rodriguez, C

2007-12-01

Exposure scenarios (ES) under REACH (Registration, Evaluation, and Authorisation of Chemicals; new EU legislation) aim to describe safe conditions of product and substance use. Both operational conditions and risk management measures (RMMs) are part of the ES. For consumer use of chemicals, one of the challenges will be to identify all of the consumer uses of a given chemical and then quantify the exposure derived from each of them. Product use categories can be established to identify in a systematic fashion how products are used. These product categories comprise products that are used similarly (e.g. paints, adhesives). They deliver information about product use characteristics, and provide an easy-to-handle tool for exchanging standardised information. For practical reasons, broad ES will have to be developed, which cover a wide range of products and use. The challenge will be to define them broadly, but not in a way that they provide such an overestimation of exposure that a next iteration or a more complex model is always needed. Tiered and targeted approaches for estimation of exposure at the right level of detail may offer the best solution. RMMs relevant for consumers include those inherent to product design (controllable) and those that are communicated to consumers as directions for use (non-controllable). Quantification of the effect of non-controllable RMMs on consumer exposure can prove to be difficult. REACH requires aggregation of exposure from all relevant identified sources. Development of appropriate methodology for realistic aggregation of exposure will be no small challenge and will likely require probabilistic approaches and comprehensive databases on populations' habits, practices and behaviours. REACH regulation aims at controlling the use of chemicals so that exposure to every chemical can be demonstrated to be safe for consumers, workers, and the environment when considered separately, but also when considered in an integrated way. This

Effect of Conditioned Stimulus Exposure during Slow Wave Sleep on Fear Memory Extinction in Humans

PubMed Central

He, Jia; Sun, Hong-Qiang; Li, Su-Xia; Zhang, Wei-Hua; Shi, Jie; Ai, Si-Zhi; Li, Yun; Li, Xiao-Jun; Tang, Xiang-Dong; Lu, Lin

2015-01-01

Study Objectives: Repeated exposure to a neutral conditioned stimulus (CS) in the absence of a noxious unconditioned stimulus (US) elicits fear memory extinction. The aim of the current study was to investigate the effects of mild tone exposure (CS) during slow wave sleep (SWS) on fear memory extinction in humans. Design: The healthy volunteers underwent an auditory fear conditioning paradigm on the experimental night, during which tones served as the CS, and a mild shock served as the US. They were then randomly assigned to four groups. Three groups were exposed to the CS for 3 or 10 min or an irrelevant tone (control stimulus, CtrS) for 10 min during SWS. The fourth group served as controls and was not subjected to any interventions. All of the subjects completed a memory test 4 h after SWS-rich stage to evaluate the effect on fear extinction. Moreover, we conducted similar experiments using an independent group of subjects during the daytime to test whether the memory extinction effect was specific to the sleep condition. Participants: Ninety-six healthy volunteers (44 males) aged 18–28 y. Measurements and Results: Participants exhibited undisturbed sleep during 2 consecutive nights, as assessed by sleep variables (all P > 0.05) from polysomnographic recordings and power spectral analysis. Participants who were re-exposed to the 10 min CS either during SWS and wakefulness exhibited attenuated fear responses (wake-10 min CS, P < 0.05; SWS-10 min CS, P < 0.01). Conclusions: Conditioned stimulus re-exposure during slow wave sleep promoted fear memory extinction without altering sleep profiles. Citation: He J, Sun HQ, Li SX, Zhang WH, Shi J, Ai SZ, Li Y, Li XJ, Tang XD, Lu L. Effect of conditioned stimulus exposure during slow wave sleep on fear memory extinction in humans. SLEEP 2015;38(3):423–431. PMID:25348121

Acute exposure to selenium disrupts associative conditioning and long-term memory recall in honey bees (Apis mellifera).

PubMed

Burden, Christina M; Elmore, Christopher; Hladun, Kristen R; Trumble, John T; Smith, Brian H

2016-05-01

A plethora of toxic compounds - including pesticides, heavy metals, and metalloids - have been detected in honey bees (Apis mellifera) and their colonies. One such compound is selenium, which bees are exposed to by consuming nectar and pollen from flowers grown in contaminated areas. Though selenium is lethal at high concentrations, sublethal exposure may also impair honey bees' ability to function normally. Examining the effect of selenium exposure on learning and memory provides a sensitive assay with which to identify sublethal effects on honey bee health and behavior. To determine whether sublethal selenium exposure causes learning and memory deficits, we used proboscis extension reflex conditioning coupled with recall tests 30min and 24h post-conditioning. We exposed forager honey bees to a single sublethal dose of selenium, and 3h later we used an olfactory conditioning assay to train the bees to discriminate between one odor associated with sucrose-reinforcement and a second unreinforced odor. Following conditioning we tested short- and long-term recall of the task. Acute exposure to as little as 1.8ng of an inorganic form of selenium (sodium selenate) before conditioning caused a reduction in behavioral performance during conditioning. And, exposure to 18ng of either an inorganic form (sodium selenate) or an organic form (methylseleno-l-cysteine) of selenium caused a reduction in the bees' performance during the long-term recall test. These concentrations of selenium are lower than those found in the nectar of plants grown in selenium-contaminated soil, indicating that even low-grade selenium toxicity produces significant learning and memory impairments. This may reduce foragers' ability to effectively gather resources for the colony or nurse bees' ability to care for and maintain a healthy colony. Copyright © 2016. Published by Elsevier Inc.

Cardiovascular conditions, hearing difficulty, and occupational noise exposure within US industries and occupations.

PubMed

Kerns, Ellen; Masterson, Elizabeth A; Themann, Christa L; Calvert, Geoffrey M

2018-06-01

The purpose of this study was to estimate the prevalence of occupational noise exposure, hearing difficulty and cardiovascular conditions within US industries and occupations, and to examine any associations of these outcomes with occupational noise exposure. National Health Interview Survey data from 2014 were examined. Weighted prevalence and adjusted prevalence ratios of self-reported hearing difficulty, hypertension, elevated cholesterol, and coronary heart disease or stroke were estimated by level of occupational noise exposure, industry, and occupation. Twenty-five percent of current workers had a history of occupational noise exposure (14% exposed in the last year), 12% had hearing difficulty, 24% had hypertension, 28% had elevated cholesterol; 58%, 14%, and 9% of these cases can be attributed to occupational noise exposure, respectively. Hypertension, elevated cholesterol, and hearing difficulty are more prevalent among noise-exposed workers. Reducing workplace noise levels is critical. Workplace-based health and wellness programs should also be considered. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Neonatal alcohol exposure disrupts hippocampal neurogenesis and contextual fear conditioning in adult rats

PubMed Central

Hamilton, G.F.; Murawski, N.J.; St. Cyr, S.A.; Jablonski, S.A.; Schiffino, F.L.; Stanton, M.E.; Klintsova, A.Y.

2011-01-01

Developmental alcohol exposure can permanently alter brain structures and produce functional impairments in many aspects of behavior, including learning and memory. This study evaluates the effect of neonatal alcohol exposure on adult neurogenesis in the dentate gyrus of the hippocampus and the implications of such exposure for hippocampus-dependent contextual fear conditioning. Alcohol-exposed rats (AE) received 5.25 g/kg/day of alcohol on postnatal days (PD) 4-9 (third trimester in humans), in a binge-like manner. Two control groups were included: sham-intubated (SI) and suckle-control (SC). Animals were housed in social cages (3/cage) after weaning. On PD80, animals were injected with 200 mg/kg BrdU. Half of the animals were sacrificed two hours later. The remainder were sacrificed on PD114 to evaluate cell survival; separate AE, SI, and SC rats not injected with BrdU were tested for the context preexposure facilitation effect (CPFE; ∼PD117). There was no difference in the number of BrdU+ cells in AE, SI and SC groups on PD80. On PD114, cell survival was significantly decreased in AE rats, demonstrating that developmental alcohol exposure damages new cells' ability to incorporate into the network and survive. Behaviorally tested SC and SI groups preexposed to the training context 24h prior to receiving a 1.5mA 2s footshock froze significantly more during the context test than their counterparts preexposed to an alternate context. AE rats failed to show the CPFE. The current study shows the detrimental, long-lasting effects of developmental alcohol exposure on hippocampal adult neurogenesis and contextual fear conditioning. PMID:21816390

Burn Pit Emissions Exposure and Respiratory and Cardiovascular Conditions Among Airborne Hazards and Open Burn Pit Registry Participants.

PubMed

Liu, Jason; Lezama, Nicholas; Gasper, Joseph; Kawata, Jennifer; Morley, Sybil; Helmer, Drew; Ciminera, Paul

2016-07-01

The aim of this study was to determine how burn pit emissions exposure is associated with the incidence of respiratory and cardiovascular conditions. We examined the associations between assumed geographic and self-reported burn pit emissions exposure and respiratory and cardiovascular outcomes in participants of the Airborne Hazards and Open Burn Pit Registry. We found significant dose-response associations for higher risk of self-reported emphysema, chronic bronchitis, or chronic obstructive pulmonary disease with increased days of deployment within 2 miles of selected burn pits (P-trend = 0.01) and self-reported burn pit smoke exposure (P-trend = 0.0005). We found associations between burn pit emissions exposure and higher incidence of post-deployment self-reported respiratory and cardiovascular conditions, but these findings should be interpreted with caution because the surrogate measurements of burn pit emissions exposure in this analysis may not reflect individual exposure levels.

Effects of the neonicotinoid pesticide thiamethoxam at field-realistic levels on microcolonies of Bombus terrestris worker bumble bees.

PubMed

Laycock, Ian; Cotterell, Katie C; O'Shea-Wheller, Thomas A; Cresswell, James E

2014-02-01

Neonicotinoid pesticides are currently implicated in the decline of wild bee populations. Bumble bees, Bombus spp., are important wild pollinators that are detrimentally affected by ingestion of neonicotinoid residues. To date, imidacloprid has been the major focus of study into the effects of neonicotinoids on bumble bee health, but wild populations are increasingly exposed to alternative neonicotinoids such as thiamethoxam. To investigate whether environmentally realistic levels of thiamethoxam affect bumble bee performance over a realistic exposure period, we exposed queenless microcolonies of Bombus terrestris L. workers to a wide range of dosages up to 98 μgkg(-1) in dietary syrup for 17 days. Results showed that bumble bee workers survived fewer days when presented with syrup dosed at 98 μg thiamethoxamkg(-1), while production of brood (eggs and larvae) and consumption of syrup and pollen in microcolonies were significantly reduced by thiamethoxam only at the two highest concentrations (39, 98 μgkg(-1)). In contrast, we found no detectable effect of thiamethoxam at levels typically found in the nectars of treated crops (between 1 and 11 μgkg(-1)). By comparison with published data, we demonstrate that during an exposure to field-realistic concentrations lasting approximately two weeks, brood production in worker bumble bees is more sensitive to imidacloprid than thiamethoxam. We speculate that differential sensitivity arises because imidacloprid produces a stronger repression of feeding in bumble bees than thiamethoxam, which imposes a greater nutrient limitation on production of brood. © 2013 Published by Elsevier Inc.

Postpositivist Realist Theory: Identity and Representation Revisited

ERIC Educational Resources Information Center

Gilpin, Lorraine S.

2006-01-01

In postpositivist realist theory, people like Paula Moya (2000) and Satya Mohanty (2000) make a space that at once reflects and informs my location as a Third-World woman of color and a Black-immigrant educator in the United States. In postpositivist realist theory, understanding emerges from one's past and present experiences and interactions as…

Diameter of the useful diffraction halo in double-exposure speckle photographs recorded under various conditions

NASA Astrophysics Data System (ADS)

Alejo, A.; Marti, L.; Moreno, A.; Ostrovskii, Iu. I.; Serra, R.

1985-06-01

Consideration is given to the relationship between the diffraction halo radius Theta(h) and the displacement (Delta) of the object in double exposed speckle photographs taken in various conditions. The numerical values of Theta(h)/Delta were obtained for several speckle recordings having exposure times in the range 0.5-3.8 s. It is shown that long exposure times did not significantly decrease the minimum measureable displacement of the object. The radii of the diffraction halo were the same in the case of both long and short exposure times.

SiC-based neutron detector in quasi-realistic working conditions: efficiency and stability at room and high temperature under fast neutron irradiations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferone, Raffaello; Issa, Fatima; Ottaviani, Laurent

In the framework of the European I SMART project, we have designed and made new SiC-based nuclear radiation detectors able to operate in harsh environments and to detect both fast and thermal neutrons. In this paper, we report experimental results of fast neutron irradiation campaign at high temperature (106 deg. C) in quasi-realistic working conditions. Our device does not suffer from high temperature, and spectra do show strong stability, preserving features. These experiments, as well as others in progress, show the I SMART SiC-based device skills to operate in harsh environments, whereas other materials would strongly suffer from degradation. Workmore » is still demanded to test our device at higher temperatures and to enhance efficiency in order to make our device fully exploitable from an industrial point of view. (authors)« less

Effects of bright light exposure on human fear conditioning, extinction, and associated prefrontal activation.

PubMed

Yoshiike, Takuya; Honma, Motoyasu; Yamada, Naoto; Kim, Yoshiharu; Kuriyama, Kenichi

2018-06-18

Bright light (BL) not only regulates human emotion and circadian physiology but can also directly modulate emotional memories. Impaired fear extinction and enhanced fear acquisition and consolidation are hallmarks of fear-circuitry disorders; thus, we tested whether BL facilitates fear extinction and inhibits fear acquisition. We randomly exposed 29 healthy humans to high- (9000 lx) or low-intensity light (<500 lx) for 15 min, near the nadir of the phase response to light, in a single-blind manner. Simultaneously with the light exposure, subjects performed fear extinction training and second fear acquisition, where a visual conditioned stimulus (CS), previously paired with an electric shock unconditioned stimulus (US), was presented without the US, while another CS was newly paired with the US. Conditioned responses (CRs) and changes in prefrontal cortex (PFC) activity were determined during encoding and delayed recall sessions. BL-exposed subjects exhibited lower extinction-related PFC activity and marginally higher acquisition-related PFC activity during light exposure than subjects exposed to control light. Twenty-four hours later, BL reduced CRs to both the extinguished and non-extinguished CSs with marginally lower extinction-related PFC activation, suggesting that BL enhanced fear extinction, while suppressing fear acquisition. Further, BL sustained tolerance to fear re-conditioning. Our results demonstrate that a single and brief BL exposure, synchronized with fear extinction and acquisition, instantaneously influences prefrontal hemodynamic responses and alleviates fear expression after 24 h. Although the specificity of BL effects deems further investigation, our findings indicate the clinical relevance of adjunctive BL intervention in exposure-based cognitive-behavioral therapy for fear-circuitry disorders. Copyright © 2018 Elsevier Inc. All rights reserved.

Acute exposure to PBDEs at an environmentally realistic concentration causes abrupt changes in the gut microbiota and host health of zebrafish.

PubMed

Chen, Lianguo; Hu, Chenyan; Lok-Shun Lai, Nelson; Zhang, Weipeng; Hua, Jianghuan; Lam, Paul K S; Lam, James C W; Zhou, Bingsheng

2018-05-02

Contamination from lower brominated PBDEs is ubiquitous in the environments. However, their effects on gut microbiota and intestinal health have not yet been investigated. This study exposed adult zebrafish to an environmentally realistic concentration of pentaBDE mixture (DE-71) at 5.0 ng/L for 7 days, after which metagenomic sequencing of the intestinal microbiome was conducted and host physiological activities in the intestine and liver were also examined. The results showed that acute exposure to DE-71 significantly shifted the gut microbial community in a sex-specific manner. Certain genera (e.g., Mycoplasma, Ruminiclostridium, unclassified Firmicutes sensu stricto, and Fusobacterium) disappeared from the DE-71-exposed intestines, resulting in decreased bacterial diversity. Bacterial metabolic functions in guts were also affected by DE-71, namely those covering energy metabolism, virulence, respiration, cell division, cell signaling, and stress response. In addition, measurement of diverse sensitive biomarkers showed that the health of male intestines was remarkably compromised by the DE-71 exposure, as indicated by the disruption to its neural signaling (serotonin), epithelial barrier integrity (tight junction protein 2), inflammatory response (interleukin 1β), oxidative stress and antioxidant capacity, as well as detoxifying potential (ethoxyresorufin-O-deethylase activity). However, female intestines maintained intact physiological activities. Compared to the direct impact on intestines, a latent effect of DE-71 was observed in livers. Co-occurrence network analysis demonstrated that the gut bacteria vigorously interacted to establish the fittest community under DE-71 stress by promoting the reproduction of favorable genera, while diminishing the survival of unfavorable ones. Significant correlations between the zebrafish gut microbiota and physiological activities (e.g., oxidative stress, detoxification, neurotransmission, and epithelial integrity) were

Are Exposures to Multiple Frequencies the Key to Future Radiofrequency Research?

PubMed Central

Sienkiewicz, Zenon; Calderón, Carolina; Broom, Kerry A.; Addison, Darren; Gavard, Amélie; Lundberg, Louise; Maslanyj, Myron

2017-01-01

There is an extensive literature investigating possible effects of exposure to radiofrequency (RF) electromagnetic fields associated with mobile phone technologies. This has not identified any public health risks with any degree of certainty. Some epidemiological studies have observed associations between heavy users of mobile phones and some types of cancer, but animal studies do not support this association, although a few studies have reported increased tumor yields. However, there is a crucial difference between epidemiology studies and laboratory work in terms of signals investigated: most people are exposed to a complex mixture of frequencies and signals at varying intensities, whereas the majority of animal studies have been performed using a single frequency or intensity. Whether this might explain the differences in outcome will be discussed, and whether there is a need for additional laboratory investigations that reproduce more accurately realistic exposure conditions will be considered. PMID:29276705

Radiation Damage to Nervous System: Designing Optimal Models for Realistic Neuron Morphology in Hippocampus

NASA Astrophysics Data System (ADS)

Batmunkh, Munkhbaatar; Bugay, Alexander; Bayarchimeg, Lkhagvaa; Lkhagva, Oidov

2018-02-01

The present study is focused on the development of optimal models of neuron morphology for Monte Carlo microdosimetry simulations of initial radiation-induced events of heavy charged particles in the specific types of cells of the hippocampus, which is the most radiation-sensitive structure of the central nervous system. The neuron geometry and particles track structures were simulated by the Geant4/Geant4-DNA Monte Carlo toolkits. The calculations were made for beams of protons and heavy ions with different energies and doses corresponding to real fluxes of galactic cosmic rays. A simple compartmental model and a complex model with realistic morphology extracted from experimental data were constructed and compared. We estimated the distribution of the energy deposition events and the production of reactive chemical species within the developed models of CA3/CA1 pyramidal neurons and DG granule cells of the rat hippocampus under exposure to different particles with the same dose. Similar distributions of the energy deposition events and concentration of some oxidative radical species were obtained in both the simplified and realistic neuron models.

Adapting realist synthesis methodology: The case of workplace harassment interventions.

PubMed

Carr, Tracey; Quinlan, Elizabeth; Robertson, Susan; Gerrard, Angie

2017-12-01

Realist synthesis techniques can be used to assess complex interventions by extracting and synthesizing configurations of contexts, mechanisms, and outcomes found in the literature. Our novel and multi-pronged approach to the realist synthesis of workplace harassment interventions describes our pursuit of theory to link macro and program level theories. After discovering the limitations of a dogmatic approach to realist synthesis, we adapted our search strategy and focused our analysis on a subset of data. We tailored our realist synthesis to understand how, why, and under what circumstances workplace harassment interventions are effective. The result was a conceptual framework to test our theory-based interventions and provide the basis for subsequent realist evaluation. Our experience documented in this article contributes to an understanding of how, under what circumstances, and with what consequences realist synthesis principles can be customized. Copyright © 2017 John Wiley & Sons, Ltd.

Adolescent delta-9-tetrahydrocannabinol (THC) exposure fails to affect THC-induced place and taste conditioning in adult male rats.

PubMed

Wakeford, Alison G P; Flax, Shaun M; Pomfrey, Rebecca L; Riley, Anthony L

2016-01-01

Adolescent initiation of drug use has been linked to problematic drug taking later in life and may represent an important variable that changes the balance of the rewarding and/or aversive effects of abused drugs which may contribute to abuse vulnerability. The current study examined the effects of adolescent THC exposure on THC-induced place preference (rewarding effects) and taste avoidance (aversive effects) conditioning in adulthood. Forty-six male Sprague-Dawley adolescent rats received eight injections of an intermediate dose of THC (3.2mg/kg) or vehicle. After these injections, animals were allowed to mature and then trained in a combined CTA/CPP procedure in adulthood (PND ~90). Animals were given four trials of conditioning with intervening water-recovery days, a final CPP test and then a one-bottle taste avoidance test. THC induced dose-dependent taste avoidance but did not produce place conditioning. None of these effects was impacted by adolescent THC exposure. Adolescent exposure to THC had no effect on THC taste and place conditioning in adulthood. The failure to see an effect of adolescent exposure was addressed in the context of other research that has assessed exposure of drugs of abuse during adolescence on drug reactivity in adulthood. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of prior amphetamine exposure on approach strategy in appetitive Pavlovian conditioning in rats.

PubMed

Simon, Nicholas W; Mendez, Ian A; Setlow, Barry

2009-03-01

Pavlovian conditioning with a discrete reward-predictive visual cue can elicit two classes of behaviors: "sign-tracking" (approach toward and contact with the cue) and "goal-tracking" (approach toward the site of reward delivery). Sign-tracking has been proposed to be linked to behavioral disorders involving compulsive reward-seeking, such as addiction. Prior exposure to psychostimulant drugs of abuse can facilitate reward-seeking behaviors through enhancements in incentive salience attribution. Thus, it was predicted that a sensitizing regimen of amphetamine exposure would increase sign-tracking behavior. The purpose of these experiments was to determine how a regimen of exposure to amphetamine affects subsequent sign-tracking behavior. Male Long-Evans rats were given daily injections of d-amphetamine (2.0 mg/kg) or saline for 5 days, then given a 7-day drug-free period followed by testing in a Pavlovian conditioning task. In experiment 1, rats were presented with a visual cue (simultaneous illumination of a light and extension of a lever) located either to the left or right of a centrally located food trough. One cue (CS+) was always followed by food delivery, whereas the other (CS-) was not. In experiment 2, rats were tested in a nondiscriminative (CS+ only) version of the task. In both experiments, amphetamine-exposed rats showed less sign-tracking and more goal-tracking compared to saline controls. Contrary to predictions, prior amphetamine exposure decreased sign-tracking and increased goal-tracking behavior. However, these results do support the hypothesis that psychostimulant exposure and incentive sensitization enhance behavior directed toward reward-proximal cues at the expense of reward-distal cues.

Experimental analysis of the vorticity and turbulent flow dynamics of a pitching airfoil at realistic flight (helicopter) conditions

NASA Astrophysics Data System (ADS)

Sahoo, Dipankar

Improved basic understanding, predictability, and controllability of vortex-dominated and unsteady aerodynamic flows are important in enhancement of the performance of next generation helicopters. The primary objective of this research project was improved understanding of the fundamental vorticity and turbulent flow physics for a dynamically stalling airfoil at realistic helicopter flight conditions. An experimental program was performed on a large-scale (C = 0.45 m) dynamically pitching NACA 0012 wing operating in the Texas A&M University large-scale wind tunnel. High-resolution particle image velocimetry data were acquired on the first 10-15% of the wing. Six test cases were examined including the unsteady (k>0) and steady (k=0) conditions. The relevant mechanical, shear and turbulent time-scales were all of comparable magnitude, which indicated that the flow was in a state of mechanical non-equilibrium, and the expected flow separation and reattachment hystersis was observed. Analyses of the databases provided new insights into the leading-edge Reynolds stress structure and the turbulent transport processes. Both of which were previously uncharacterized. During the upstroke motion of the wing, a bubble structure formed in the leading-edge Reynolds shear stress. The size of the bubble increased with increasing angle-of-attack before being diffused into a shear layer at full separation. The turbulent transport analyses indicated that the axial stress production was positive, where the transverse production was negative. This implied that axial turbulent stresses were being produced from the axial component of the mean flow. A significant portion of the energy was transferred to the transverse stress through the pressure-strain redistribution, and then back to the transverse mean flow through the negative transverse production. An opposite trend was observed further downstream of this region.

Exposure to multiple cholinergic pesticides impairs olfactory learning and memory in honeybees.

PubMed

Williamson, Sally M; Wright, Geraldine A

2013-05-15

Pesticides are important agricultural tools often used in combination to avoid resistance in target pest species, but there is growing concern that their widespread use contributes to the decline of pollinator populations. Pollinators perform sophisticated behaviours while foraging that require them to learn and remember floral traits associated with food, but we know relatively little about the way that combined exposure to multiple pesticides affects neural function and behaviour. The experiments reported here show that prolonged exposure to field-realistic concentrations of the neonicotinoid imidacloprid and the organophosphate acetylcholinesterase inhibitor coumaphos and their combination impairs olfactory learning and memory formation in the honeybee. Using a method for classical conditioning of proboscis extension, honeybees were trained in either a massed or spaced conditioning protocol to examine how these pesticides affected performance during learning and short- and long-term memory tasks. We found that bees exposed to imidacloprid, coumaphos, or a combination of these compounds, were less likely to express conditioned proboscis extension towards an odor associated with reward. Bees exposed to imidacloprid were less likely to form a long-term memory, whereas bees exposed to coumaphos were only less likely to respond during the short-term memory test after massed conditioning. Imidacloprid, coumaphos and a combination of the two compounds impaired the bees' ability to differentiate the conditioned odour from a novel odour during the memory test. Our results demonstrate that exposure to sublethal doses of combined cholinergic pesticides significantly impairs important behaviours involved in foraging, implying that pollinator population decline could be the result of a failure of neural function of bees exposed to pesticides in agricultural landscapes.

Exposure to multiple cholinergic pesticides impairs olfactory learning and memory in honeybees

PubMed Central

Williamson, Sally M.; Wright, Geraldine A.

2013-01-01

SUMMARY Pesticides are important agricultural tools often used in combination to avoid resistance in target pest species, but there is growing concern that their widespread use contributes to the decline of pollinator populations. Pollinators perform sophisticated behaviours while foraging that require them to learn and remember floral traits associated with food, but we know relatively little about the way that combined exposure to multiple pesticides affects neural function and behaviour. The experiments reported here show that prolonged exposure to field-realistic concentrations of the neonicotinoid imidacloprid and the organophosphate acetylcholinesterase inhibitor coumaphos and their combination impairs olfactory learning and memory formation in the honeybee. Using a method for classical conditioning of proboscis extension, honeybees were trained in either a massed or spaced conditioning protocol to examine how these pesticides affected performance during learning and short- and long-term memory tasks. We found that bees exposed to imidacloprid, coumaphos, or a combination of these compounds, were less likely to express conditioned proboscis extension towards an odor associated with reward. Bees exposed to imidacloprid were less likely to form a long-term memory, whereas bees exposed to coumaphos were only less likely to respond during the short-term memory test after massed conditioning. Imidacloprid, coumaphos and a combination of the two compounds impaired the bees' ability to differentiate the conditioned odour from a novel odour during the memory test. Our results demonstrate that exposure to sublethal doses of combined cholinergic pesticides significantly impairs important behaviours involved in foraging, implying that pollinator population decline could be the result of a failure of neural function of bees exposed to pesticides in agricultural landscapes. PMID:23393272

Realistic Real-Time Outdoor Rendering in Augmented Reality

PubMed Central

Kolivand, Hoshang; Sunar, Mohd Shahrizal

2014-01-01

Realistic rendering techniques of outdoor Augmented Reality (AR) has been an attractive topic since the last two decades considering the sizeable amount of publications in computer graphics. Realistic virtual objects in outdoor rendering AR systems require sophisticated effects such as: shadows, daylight and interactions between sky colours and virtual as well as real objects. A few realistic rendering techniques have been designed to overcome this obstacle, most of which are related to non real-time rendering. However, the problem still remains, especially in outdoor rendering. This paper proposed a much newer, unique technique to achieve realistic real-time outdoor rendering, while taking into account the interaction between sky colours and objects in AR systems with respect to shadows in any specific location, date and time. This approach involves three main phases, which cover different outdoor AR rendering requirements. Firstly, sky colour was generated with respect to the position of the sun. Second step involves the shadow generation algorithm, Z-Partitioning: Gaussian and Fog Shadow Maps (Z-GaF Shadow Maps). Lastly, a technique to integrate sky colours and shadows through its effects on virtual objects in the AR system, is introduced. The experimental results reveal that the proposed technique has significantly improved the realism of real-time outdoor AR rendering, thus solving the problem of realistic AR systems. PMID:25268480

Realistic real-time outdoor rendering in augmented reality.

PubMed

Kolivand, Hoshang; Sunar, Mohd Shahrizal

2014-01-01

Realistic rendering techniques of outdoor Augmented Reality (AR) has been an attractive topic since the last two decades considering the sizeable amount of publications in computer graphics. Realistic virtual objects in outdoor rendering AR systems require sophisticated effects such as: shadows, daylight and interactions between sky colours and virtual as well as real objects. A few realistic rendering techniques have been designed to overcome this obstacle, most of which are related to non real-time rendering. However, the problem still remains, especially in outdoor rendering. This paper proposed a much newer, unique technique to achieve realistic real-time outdoor rendering, while taking into account the interaction between sky colours and objects in AR systems with respect to shadows in any specific location, date and time. This approach involves three main phases, which cover different outdoor AR rendering requirements. Firstly, sky colour was generated with respect to the position of the sun. Second step involves the shadow generation algorithm, Z-Partitioning: Gaussian and Fog Shadow Maps (Z-GaF Shadow Maps). Lastly, a technique to integrate sky colours and shadows through its effects on virtual objects in the AR system, is introduced. The experimental results reveal that the proposed technique has significantly improved the realism of real-time outdoor AR rendering, thus solving the problem of realistic AR systems.

Echolocation behavior in big brown bats is not impaired after intense broadband noise exposures.

PubMed

Hom, Kelsey N; Linnenschmidt, Meike; Simmons, James A; Simmons, Andrea Megela

2016-10-15

Echolocating bats emit trains of intense ultrasonic biosonar pulses and listen to weaker echoes returning from objects in their environment. Identification and categorization of echoes are crucial for orientation and prey capture. Bats are social animals and often fly in groups in which they are exposed to their own emissions and to those from other bats, as well as to echoes from multiple surrounding objects. Sound pressure levels in these noisy conditions can exceed 110 dB, with no obvious deleterious effects on echolocation performance. Psychophysical experiments show that big brown bats (Eptesicus fuscus) do not experience temporary threshold shifts after exposure to intense broadband ultrasonic noise, but it is not known if they make fine-scale adjustments in their pulse emissions to compensate for any effects of the noise. We investigated whether big brown bats adapt the number, temporal patterning or relative amplitude of their emitted pulses while flying through an acoustically cluttered corridor after exposure to intense broadband noise (frequency range 10-100 kHz; sound exposure level 152 dB). Under these conditions, four bats made no significant changes in navigation errors or in pulse number, timing and amplitude 20 min, 24 h or 48 h after noise exposure. These data suggest that big brown bats remain able to perform difficult echolocation tasks after exposure to ecologically realistic levels of broadband noise. © 2016. Published by The Company of Biologists Ltd.

Generating realistic images using Kray

NASA Astrophysics Data System (ADS)

Tanski, Grzegorz

2004-07-01

Kray is an application for creating realistic images. It is written in C++ programming language, has a text-based interface, solves global illumination problem using techniques such as radiosity, path tracing and photon mapping.

Prior exposure to a single stress session facilitates subsequent contextual fear conditioning in rats. Evidence for a role of corticosterone.

PubMed

Cordero, M Isabel; Venero, Cesar; Kruyt, Nyika D; Sandi, Carmen

2003-11-01

Previous studies showed that exposure of rats to chronic restraint stress for 21 days enhances subsequent contextual fear conditioning. Since recent evidence suggest that this effect is not dependent on stress-induced neurodegenerative processes, but to elevated training-elicited glucocorticoid release in chronically stressed animals, we aimed to explore here whether a single exposure to restraint stress, which is not expected to induce neuronal damage, would also affect contextual fear conditioning. We also questioned whether post-training corticosterone levels might be associated with any potential effect of stress on fear conditioning. Adult male Wistar rats were exposed to acute restraint stress for 2 h and, two days later, trained in the contextual fear conditioning task, under training conditions involving either moderate (0.4 mA shock) or high (1 mA shock) stress levels. The results showed that acute stress enhanced conditioned freezing at both training conditions, although data from the 1 mA shock intensity experiment only approached significance. Stressed animals were shown to display higher post-training corticosterone levels. Furthermore, the facilitating effect of prior stress was not evident when animals were trained in the hippocampal-independent auditory-cued conditioning task. Therefore, these findings support the idea that stress experiences preceding exposure to new types of stressors facilitate the development of contextual fear conditioning. They also indicate that not only repeated, but also a single exposure to aversive stimulation is sufficient to facilitate context-dependent fear conditioning, and suggest that increased glucocorticoid release at training might be implicated in the mechanisms mediating the memory facilitating effects induced by prior stress experiences.

The effects of intermittent exposure to low pH and oxygen conditions on survival and growth of juvenile red abalone

NASA Astrophysics Data System (ADS)

Kim, T. W.; Barry, J. P.; Micheli, F.

2013-02-01

Exposure of nearshore animals to hypoxic, low pH waters upwelled from below the continental shelf and advected near the coast may be stressful to marine organisms and lead to impaired physiological performance. We mimicked upwelling conditions in the laboratory and tested the effect of fluctuating exposure to water with low pH and/or low oxygen levels on the mortality and growth of juvenile red abalone (Haliotis rufescens, shell length 5-10 mm). Mortality rates of juvenile abalone exposed to low pH (7.5, total scale) and low O2 (40% saturation, 5 mg L-1) conditions for periods of 3 to 6 h every 3-5 days over 2 weeks did not differ from those exposed to control conditions (O2: 100% saturation, 12 mg L-1; pH 8.0). However, when exposure was extended to 24 h repeated twice over a 15 day period, juveniles experienced higher mortality in the low oxygen treatments compared to control conditions, regardless of pH levels (pH 7.5 vs. 8.0). Growth rates were reduced significantly when juveniles were exposed to low pH or low oxygen treatments and the growth was lowest when low pH exposure was combined with low O2. Furthermore, individual variation of growth rate increased when they were exposed to low pH and low O2 conditions. These results indicate that prolonged exposure to low oxygen levels is detrimental for the survival of red abalone, whereas both pH and oxygen is a crucial factor for their growth. However, given the higher individual variation in growth rate, they may have an ability to adapt to extended exposure to upwelling conditions.

Effect of conditioned stimulus exposure during slow wave sleep on fear memory extinction in humans.

PubMed

He, Jia; Sun, Hong-Qiang; Li, Su-Xia; Zhang, Wei-Hua; Shi, Jie; Ai, Si-Zhi; Li, Yun; Li, Xiao-Jun; Tang, Xiang-Dong; Lu, Lin

2015-03-01

Repeated exposure to a neutral conditioned stimulus (CS) in the absence of a noxious unconditioned stimulus (US) elicits fear memory extinction. The aim of the current study was to investigate the effects of mild tone exposure (CS) during slow wave sleep (SWS) on fear memory extinction in humans. The healthy volunteers underwent an auditory fear conditioning paradigm on the experimental night, during which tones served as the CS, and a mild shock served as the US. They were then randomly assigned to four groups. Three groups were exposed to the CS for 3 or 10 min or an irrelevant tone (control stimulus, CtrS) for 10 min during SWS. The fourth group served as controls and was not subjected to any interventions. All of the subjects completed a memory test 4 h after SWS-rich stage to evaluate the effect on fear extinction. Moreover, we conducted similar experiments using an independent group of subjects during the daytime to test whether the memory extinction effect was specific to the sleep condition. Ninety-six healthy volunteers (44 males) aged 18-28 y. Participants exhibited undisturbed sleep during 2 consecutive nights, as assessed by sleep variables (all P > 0.05) from polysomnographic recordings and power spectral analysis. Participants who were re-exposed to the 10 min CS either during SWS and wakefulness exhibited attenuated fear responses (wake-10 min CS, P < 0.05; SWS-10 min CS, P < 0.01). Conditioned stimulus re-exposure during SWS promoted fear memory extinction without altering sleep profiles. © 2015 Associated Professional Sleep Societies, LLC.

Isotopically modified silver nanoparticles to assess nanosilver bioavailability and toxicity at environmentally relevant exposures

USGS Publications Warehouse

Croteau, Marie-Noële; Dybowska, Agnieszka D.; Luoma, Samuel N.; Misra, Superb K.; Valsami-Jones, Eugenia

2014-01-01

A major challenge in understanding the environmental implications of nanotechnology lies in studying nanoparticle uptake in organisms at environmentally realistic exposure concentrations. Typically, high exposure concentrations are needed to trigger measurable effects and to detect accumulation above background. But application of tracer techniques can overcome these limitations. Here we synthesised, for the first time, citrate-coated Ag nanoparticles using Ag that was 99.7 % 109Ag. In addition to conducting reactivity and dissolution studies, we assessed the bioavailability and toxicity of these isotopically modified Ag nanoparticles (109Ag NPs) to a freshwater snail under conditions typical of nature. We showed that accumulation of 109Ag from 109Ag NPs is detectable in the tissues of Lymnaea stagnalis after 24-h exposure to aqueous concentrations as low as 6 ng L–1 as well as after 3 h of dietary exposure to concentrations as low as 0.07 μg g–1. Silver uptake from unlabelled Ag NPs would not have been detected under similar exposure conditions. Uptake rates of 109Ag from 109Ag NPs mixed with food or dispersed in water were largely linear over a wide range of concentrations. Particle dissolution was most important at low waterborne concentrations. We estimated that 70 % of the bioaccumulated 109Ag concentration in L. stagnalis at exposures –1 originated from the newly solubilised Ag. Above this concentration, we predicted that 80 % of the bioaccumulated 109Ag concentration originated from the 109Ag NPs. It was not clear if agglomeration had a major influence on uptake rates.

Aquatic risk assessment of a realistic exposure to pesticides used in bulb crops: a microcosm study.

PubMed

van Wijngaarden, René P A; Cuppen, Jan G M; Arts, Gertie H P; Crum, Steven J H; van den Hoorn, Martin W; van den Brink, Paul J; Brock, Theo C M

2004-06-01

The fungicide fluazinam, the insecticide lambda-cyhalothrin, and the herbicides asulam and metamitron were applied to indoor freshwater microcosms (water volume approximately 0.6 m3). The treatment regime was based on a realistic application scenario in tulip cultivation. Concentrations of each pesticide were equal to 0%, 0.2%, 0.5%, 2%, and 5% spray drift emission of label-recommended rates. Contribution of compounds to the toxicity of the pesticide package was established by expressing their concentrations as fractions of toxic units. The fate of the compounds in the water, and responses of phytoplankton, zooplankton, periphyton, macroinvertebrates, macrophytes, decomposition, and water quality were followed for 13 weeks. The half-lives of lambda-cyhalothrin, metamitron, and fluazinam were 1 to 2 d; that of asulam was >30 d. No consistent effects could be demonstrated for the 0.2% treatment regime that was therefore considered the no-observed-effect concentration community (NOEC). The macroinvertebrate populations of Gammarus pulex, Asellus aquaticus, and Proasellus meridianus were the most sensitive end points, followed by species of copepods and cladocerans. Responses mainly were due to lambda-cyhalothrin. The 0.5% treatment regime resulted in short-term effects. Pronounced effects were observed at the 2% and 5% treatment levels. At the end of the experiment, the macrophyte biomass that consisted of Elodea nuttallii, showed a decline at the two highest treatment levels, asulam being the causal factor (NOEC: 0.5% treatment level). Primary production was reduced at the 5% treatment level only. In our experiment, the first-tier risk assessment procedure for individual compounds was adequate for protecting sensitive populations exposed to realistic combinations of pesticides. Spray drift reduction measures seem to be efficient in protecting aquatic ecosystems in agricultural areas.

Critical Evaluation of Air-Liquid Interface Exposure Devices for In Vitro Assessment of Atmospheric Pollutants

EPA Science Inventory

Exposure of cells to atmospheric pollutants at the air-liquid interface (ALI) is a more realistic approach than exposures of attached cells submerged in liquid medium. However, there is still limited understanding of the ideal ALI device design features that permit reproducible a...

Elodea nuttallii exposure to mercury exposure under enhanced ultraviolet radiation: Effects on bioaccumulation, transcriptome, pigment content and oxidative stress.

PubMed

Regier, Nicole; Beauvais-Flück, Rebecca; Slaveykova, Vera I; Cosio, Claudia

2016-11-01

The hypothesis that increased UV radiation result in co-tolerance to Hg toxicity in aquatic plants was studied at the physiological and transcriptomic level in Elodea nuttallii. At the transcriptomic level, combined exposure to UV+Hg enhanced the stress response in comparison with single treatments, affecting the expression level of transcripts involved in energy metabolism, lipid metabolism, nutrition, and redox homeostasis. Single and combined UV and Hg treatments dysregulated different genes but with similar functions, suggesting a fine regulation of the plant to stresses triggered by Hg, UV and their combination but lack of co-tolerance. At the physiological level, UV+Hg treatment reduced chlorophyll content and depleted antioxidative compounds such as anthocyanin and GSH/GSSG in E. nuttallii. Nonetheless, combined exposure to UV+Hg resulted in about 30% reduction of Hg accumulation into shoots vs exposure to Hg alone, which was congruent with the level of expression of several transporter genes, as well as the UV effect on Hg bioavailability in water. The findings of the present work underlined the importance of performing experimentation under environmentally realistic conditions and to consider the interplay between contaminants and environmental variables such as light that might have confounding effects to better understand and anticipate the effects of multiple stressors in aquatic environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of combined dredging-related stressors on sponges: a laboratory approach using realistic scenarios.

PubMed

Pineda, Mari-Carmen; Strehlow, Brian; Kamp, Jasmine; Duckworth, Alan; Jones, Ross; Webster, Nicole S

2017-07-12

Dredging can cause increased suspended sediment concentrations (SSCs), light attenuation and sedimentation in marine communities. In order to determine the combined effects of dredging-related pressures on adult sponges, three species spanning different nutritional modes and morphologies were exposed to 5 treatment levels representing realistic dredging scenarios. Most sponges survived under low to moderate turbidity scenarios (SSCs of ≤ 33 mg L -1 , and a daily light integral of ≥0.5 mol photons m -2 d -1 ) for up to 28 d. However, under the highest turbidity scenario (76 mg L -1 , 0.1 mol photons m -2 d -1 ) there was 20% and 90% mortality of the phototrophic sponges Cliona orientalis and Carteriospongia foliascens respectively, and tissue regression in the heterotrophic Ianthella basta. All three sponge species exhibited mechanisms to effectively tolerate dredging-related pressures in the short term (e.g. oscula closure, mucus production and tissue regression), although reduced lipids and deterioration of sponge health suggest that longer term exposure to similar conditions is likely to result in higher mortality. These results suggest that the combination of high SSCs and low light availability can accelerate mortality, increasing the probability of biological effects, although there is considerable interspecies variability in how adult sponges respond to dredging pressures.

Realistic modeling of neurons and networks: towards brain simulation.

PubMed

D'Angelo, Egidio; Solinas, Sergio; Garrido, Jesus; Casellato, Claudia; Pedrocchi, Alessandra; Mapelli, Jonathan; Gandolfi, Daniela; Prestori, Francesca

2013-01-01

Realistic modeling is a new advanced methodology for investigating brain functions. Realistic modeling is based on a detailed biophysical description of neurons and synapses, which can be integrated into microcircuits. The latter can, in turn, be further integrated to form large-scale brain networks and eventually to reconstruct complex brain systems. Here we provide a review of the realistic simulation strategy and use the cerebellar network as an example. This network has been carefully investigated at molecular and cellular level and has been the object of intense theoretical investigation. The cerebellum is thought to lie at the core of the forward controller operations of the brain and to implement timing and sensory prediction functions. The cerebellum is well described and provides a challenging field in which one of the most advanced realistic microcircuit models has been generated. We illustrate how these models can be elaborated and embedded into robotic control systems to gain insight into how the cellular properties of cerebellar neurons emerge in integrated behaviors. Realistic network modeling opens up new perspectives for the investigation of brain pathologies and for the neurorobotic field.

Realistic modeling of neurons and networks: towards brain simulation

PubMed Central

D’Angelo, Egidio; Solinas, Sergio; Garrido, Jesus; Casellato, Claudia; Pedrocchi, Alessandra; Mapelli, Jonathan; Gandolfi, Daniela; Prestori, Francesca

Summary Realistic modeling is a new advanced methodology for investigating brain functions. Realistic modeling is based on a detailed biophysical description of neurons and synapses, which can be integrated into microcircuits. The latter can, in turn, be further integrated to form large-scale brain networks and eventually to reconstruct complex brain systems. Here we provide a review of the realistic simulation strategy and use the cerebellar network as an example. This network has been carefully investigated at molecular and cellular level and has been the object of intense theoretical investigation. The cerebellum is thought to lie at the core of the forward controller operations of the brain and to implement timing and sensory prediction functions. The cerebellum is well described and provides a challenging field in which one of the most advanced realistic microcircuit models has been generated. We illustrate how these models can be elaborated and embedded into robotic control systems to gain insight into how the cellular properties of cerebellar neurons emerge in integrated behaviors. Realistic network modeling opens up new perspectives for the investigation of brain pathologies and for the neurorobotic field. PMID:24139652

Case management in primary care among frequent users of healthcare services with chronic conditions: protocol of a realist synthesis.

PubMed

Hudon, Catherine; Chouinard, Maud-Christine; Aubrey-Bassler, Kris; Muhajarine, Nazeem; Burge, Fred; Pluye, Pierre; Bush, Paula L; Ramsden, Vivian R; Legare, France; Guenette, Line; Morin, Paul; Lambert, Mireille; Groulx, Antoine; Couture, Martine; Campbell, Cameron; Baker, Margaret; Edwards, Lynn; Sabourin, Véronique; Spence, Claude; Gauthier, Gilles; Warren, Mike; Godbout, Julie; Davis, Breanna; Rabbitskin, Norma

2017-09-03

A common reason for frequent use of healthcare services is the complex healthcare needs of individuals suffering from multiple chronic conditions, especially in combination with mental health comorbidities and/or social vulnerability. Frequent users (FUs) of healthcare services are more at risk for disability, loss of quality of life and mortality. Case management (CM) is a promising intervention to improve care integration for FU and to reduce healthcare costs. This review aims to develop a middle-range theory explaining how CM in primary care improves outcomes among FU with chronic conditions, for what types of FU and in what circumstances. A realist synthesis (RS) will be conducted between March 2017 and March 2018 to explore the causal mechanisms that underlie CM and how contextual factors influence the link between these causal mechanisms and outcomes. According to RS methodology, five steps will be followed: (1) focusing the scope of the RS; (2) searching for the evidence; (3) appraising the quality of evidence; (4) extracting the data; and (5) synthesising the evidence. Patterns in context-mechanism-outcomes (CMOs) configurations will be identified, within and across identified studies. Analysis of CMO configurations will help confirm, refute, modify or add to the components of our initial rough theory and ultimately produce a refined theory explaining how and why CM interventions in primary care works, in which contexts and for which FU with chronic conditions. Research ethics is not required for this review, but publication guidelines on RS will be followed. Based on the review findings, we will develop and disseminate messages tailored to various relevant stakeholder groups. These messages will allow the development of material that provides guidance on the design and the implementation of CM in health organisations. Prospero CRD42017057753. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights

A Radiosity Approach to Realistic Image Synthesis

DTIC Science & Technology

1992-12-01

AD-A259 082 AFIT/GCE/ENG/92D-09 A RADIOSITY APPROACH TO REALISTIC IMAGE SYNTHESIS THESIS Richard L. Remington Captain, USAF fl ECTE AFIT/GCE/ENG/92D...09 SJANl 1993U 93-00134 Approved for public release; distribution unlimited 93& 1! A -A- AFIT/GCE/ENG/92D-09 A RADIOSITY APPROACH TO REALISTIC IMAGE...assistance in creating the input geometry file for the AWACS aircraft interior. Without his assistance, a good model for the diffuse radiosity implementation

Assessment of tbe Performance of Ablative Insulators Under Realistic Solid Rocket Motor Operating Conditions (a Doctoral Dissertation)

NASA Technical Reports Server (NTRS)

Martin, Heath Thomas

2013-01-01

Ablative insulators are used in the interior surfaces of solid rocket motors to prevent the mechanical structure of the rocket from failing due to intense heating by the high-temperature solid-propellant combustion products. The complexity of the ablation process underscores the need for ablative material response data procured from a realistic solid rocket motor environment, where all of the potential contributions to material degradation are present and in their appropriate proportions. For this purpose, the present study examines ablative material behavior in a laboratory-scale solid rocket motor. The test apparatus includes a planar, two-dimensional flow channel in which flat ablative material samples are installed downstream of an aluminized solid propellant grain and imaged via real-time X-ray radiography. In this way, the in-situ transient thermal response of an ablator to all of the thermal, chemical, and mechanical erosion mechanisms present in a solid rocket environment can be observed and recorded. The ablative material is instrumented with multiple micro-thermocouples, so that in-depth temperature histories are known. Both total heat flux and thermal radiation flux gauges have been designed, fabricated, and tested to characterize the thermal environment to which the ablative material samples are exposed. These tests not only allow different ablative materials to be compared in a realistic solid rocket motor environment but also improve the understanding of the mechanisms that influence the erosion behavior of a given ablative material.

Interprofessional education in a student-led emergency department: A realist evaluation.

PubMed

Ericson, Anne; Löfgren, Susanne; Bolinder, Gunilla; Reeves, Scott; Kitto, Simon; Masiello, Italo

2017-03-01

This article reports a realist evaluation undertaken to identify factors that facilitated or hindered the successful implementation of interprofessional clinical training for undergraduate students in an emergency department. A realist evaluation provides a framework for understanding how the context and underlying mechanisms affect the outcome patterns of an intervention. The researchers gathered both qualitative and quantitative data from internal documents, semi-structured interviews, observations, and questionnaires to study what worked, for whom, and under what circumstances in this specific interprofessional setting. The study participants were medical, nursing, and physiotherapy students, their supervisors, and two members of the emergency department's management staff. The data analysis indicated that the emergency ward provided an excellent environment for interprofessional education (IPE), as attested by the students, supervisors, and the clinical managers. An essential prerequisite is that the students have obtained adequate skills to work independently. Exemplary conditions for IPE to work well in an emergency department demand the continuity of effective and encouraging supervision throughout the training period and supervisors who are knowledgeable about developing a team.

Noise exposure in marching bands

NASA Astrophysics Data System (ADS)

Keefe, Joseph

2005-09-01

Previous studies involving orchestras have shown that music ensembles can produce hazardous noise levels. There are no similar data for marching bands and pep bands. In order to evaluate the noise levels produced by marching and pep bands, 1/3-octave-band sound-pressure levels were measured while these groups rehearsed and performed. Data were collected while marching with the bands to ensure a realistic environment. Comparing these data to OSHA and NIOSH criteria, marching and pep band exposures often exceed safe values. For typical exposures, OSHA doses range from 11% to 295%, while NIOSH doses range from 35% to 3055%. Exposures that would be considered hazardous in the workplace are common in marching and pep bands; students and band directors should take steps to recognize the risk posed by various instruments and various locations, and should implement hearing conservation efforts.

Survey of Approaches to Generate Realistic Synthetic Graphs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Seung-Hwan; Lee, Sangkeun; Powers, Sarah S

A graph is a flexible data structure that can represent relationships between entities. As with other data analysis tasks, the use of realistic graphs is critical to obtaining valid research results. Unfortunately, using the actual ("real-world") graphs for research and new algorithm development is difficult due to the presence of sensitive information in the data or due to the scale of data. This results in practitioners developing algorithms and systems that employ synthetic graphs instead of real-world graphs. Generating realistic synthetic graphs that provide reliable statistical confidence to algorithmic analysis and system evaluation involves addressing technical hurdles in a broadmore » set of areas. This report surveys the state of the art in approaches to generate realistic graphs that are derived from fitted graph models on real-world graphs.« less

Impact of Soil Cadmium on Land Snails: A Two-Stage Exposure Approach under Semi-Field Conditions Using Bioaccumulative and Conchological End-Points of Exposure

PubMed Central

Nica, Dragos V.; Filimon, Marioara Nicoleta; Bordean, Despina-Maria; Harmanescu, Monica; Draghici, George Andrei; Dragan, Simona; Gergen, Iosif I.

2015-01-01

Land snails are highly tolerant to cadmium exposure and are able to accumulate soil cadmium independently of food ingestion. However, little information exists on the kinetics of cadmium retention in terrestrial gastropods exposed to an increase in the soil cadmium content, over time. There is also little knowledge about how exposure to cadmium-polluted soils influences shell growth and architecture. In this context, we examined cadmium accumulation in the hepatopancreas and shell of juvenile Cantareus aspersus exposed to elevating high levels of cadmium in soil. Also, the toxicity of cadmium to snails was assessed using a range of conchological endpoints, including shell height, width, volume, allometry and integrity. Test snails, aged three months, were reared under semi-field conditions, fed an uncontaminated diet and exposed first, for a period of 30 days, to a series of soil cadmium concentrations, and then, for a second period of 30 days, to soils with higher cadmium content. Cadmium showed a dose-dependent accumulation in both the hepatopancreas and shell. The kinetics of cadmium retention in the hepatopancreas of snails previously exposed to cadmium-spiked soils was significantly influenced by a new exposure event. The shell was not a relevant bioaccumulator for soil cadmium. Under the present experimental conditions, only high cadmium exposure significantly affected either the shell growth or snail survival. There was no consistent effect on shell allometry, but the shell integrity, especially in rapidly growing parts, appeared to be affected by high cadmium exposure. Our results attest to the value of hepatopancreas for describing cadmium retention in land snails and to the difficulty of using conchological parameters in field surveys for estimating the environmental hazard of soil cadmium. PMID:25790135

Designing field-controllable graphene-dot-graphene single molecule switches: A quantum-theoretical proof-of-concept under realistic operating conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pejov, Ljupčo, E-mail: ljupcop@pmf.ukim.mk; Petreska, Irina; Kocarev, Ljupčo

2015-12-28

A theoretical proof of the concept that a particularly designed graphene-based moletronics device, constituted by two semi-infinite graphene subunits, acting as source and drain electrodes, and a central benzenoid ring rotator (a “quantum dot”), could act as a field-controllable molecular switch is outlined and analyzed with the density functional theory approach. Besides the ideal (0 K) case, we also consider the operation of such a device under realistic operating (i.e., finite-temperature) conditions. An in-depth insight into the physics behind device controllability by an external field was gained by thorough analyses of the torsional potential of the dot under various conditionsmore » (absence or presence of an external gating field with varying strength), computing the torsional correlation time and transition probabilities within the Bloembergen-Purcell-Pound formalism. Both classical and quantum mechanical tunneling contributions to the intramolecular rotation were considered in the model. The main idea that we put forward in the present study is that intramolecular rotors can be controlled by the gating field even in cases when these groups do not possess a permanent dipole moment (as in cases considered previously by us [I. Petreska et al., J. Chem. Phys. 134, 014708-1–014708-12 (2011)] and also by other groups [P. E. Kornilovitch et al., Phys. Rev. B 66, 245413-1–245413-7 (2002)]). Consequently, one can control the molecular switching properties by an external electrostatic field utilizing even nonpolar intramolecular rotors (i.e., in a more general case than those considered so far). Molecular admittance of the currently considered graphene-based molecular switch under various conditions is analyzed employing non-equilibrium Green’s function formalism, as well as by analysis of frontier molecular orbitals’ behavior.« less

Transition from children's to adult services for young adults with life-limiting conditions: A realist review of the literature.

PubMed

Kerr, Helen; Price, Jayne; Nicholl, Honor; O'Halloran, Peter

2017-11-01

Improvements in care and treatment have led to more young adults with life-limiting conditions living beyond childhood, which means they must make the transition from children's to adult services. This has proved a challenging process for both young adults and service providers, with complex transition interventions interacting in unpredictable ways with local contexts. To explain how intervention processes interact with contextual factors to help transition from children's to adult services for young adults with life-limiting conditions. Systematic realist review of the literature. Literature was sourced from four electronic databases: Embase, MEDLINE, Science Direct and Cochrane Library from January 1995 to April 2016. This was supplemented with a search in Google Scholar and articles sourced from reference lists of included papers. Data were extracted using an adapted standardised data extraction tool which included identifying information related to interventions, mechanisms, contextual influences and outcomes. Two reviewers assessed the relevance of papers based on the inclusion criteria. Methodological rigor was assessed using the relevant Critical Appraisal Skills Programme tools. 78 articles were included in the review. Six interventions were identified related to an effective transition to adult services. Contextual factors include the need for children's service providers to collaborate with adult service providers to prepare an environment with knowledgeable staff and adequate resources. Mechanisms triggered by the interventions include a sense of empowerment and agency amongst all stakeholders. Early planning, collaboration between children's and adult service providers, and a focus on increasing the young adults' confidence in decision-making and engaging with adult services, are vital to a successful transition. Interventions should be tailored to their context and focused not only on organisational procedures but on equipping young adults, parents

A Low-cost System for Generating Near-realistic Virtual Actors

NASA Astrophysics Data System (ADS)

Afifi, Mahmoud; Hussain, Khaled F.; Ibrahim, Hosny M.; Omar, Nagwa M.

2015-06-01

Generating virtual actors is one of the most challenging fields in computer graphics. The reconstruction of a realistic virtual actor has been paid attention by the academic research and the film industry to generate human-like virtual actors. Many movies were acted by human-like virtual actors, where the audience cannot distinguish between real and virtual actors. The synthesis of realistic virtual actors is considered a complex process. Many techniques are used to generate a realistic virtual actor; however they usually require expensive hardware equipment. In this paper, a low-cost system that generates near-realistic virtual actors is presented. The facial features of the real actor are blended with a virtual head that is attached to the actor's body. Comparing with other techniques that generate virtual actors, the proposed system is considered a low-cost system that requires only one camera that records the scene without using any expensive hardware equipment. The results of our system show that the system generates good near-realistic virtual actors that can be used on many applications.

Problem Posing with Realistic Mathematics Education Approach in Geometry Learning

NASA Astrophysics Data System (ADS)

Mahendra, R.; Slamet, I.; Budiyono

2017-09-01

One of the difficulties of students in the learning of geometry is on the subject of plane that requires students to understand the abstract matter. The aim of this research is to determine the effect of Problem Posing learning model with Realistic Mathematics Education Approach in geometry learning. This quasi experimental research was conducted in one of the junior high schools in Karanganyar, Indonesia. The sample was taken using stratified cluster random sampling technique. The results of this research indicate that the model of Problem Posing learning with Realistic Mathematics Education Approach can improve students’ conceptual understanding significantly in geometry learning especially on plane topics. It is because students on the application of Problem Posing with Realistic Mathematics Education Approach are become to be active in constructing their knowledge, proposing, and problem solving in realistic, so it easier for students to understand concepts and solve the problems. Therefore, the model of Problem Posing learning with Realistic Mathematics Education Approach is appropriately applied in mathematics learning especially on geometry material. Furthermore, the impact can improve student achievement.

Pregnancy exposure to atmospheric pollution and meteorological conditions and placental DNA methylation.

PubMed

Abraham, Emilie; Rousseaux, Sophie; Agier, Lydiane; Giorgis-Allemand, Lise; Tost, Jörg; Galineau, Julien; Hulin, Agnès; Siroux, Valérie; Vaiman, Daniel; Charles, Marie-Aline; Heude, Barbara; Forhan, Anne; Schwartz, Joel; Chuffart, Florent; Bourova-Flin, Ekaterina; Khochbin, Saadi; Slama, Rémy; Lepeule, Johanna

2018-06-19

Air pollution exposure represents a major health threat to the developing foetus. DNA methylation is one of the most well-known molecular determinants of the epigenetic status of cells. Blood DNA methylation has been proven sensitive to air pollutants, but the molecular impact of air pollution on new-borns has so far received little attention. We investigated whether nitrogen dioxide (NO 2 ), particulate matter (PM 10 ), temperature and humidity during pregnancy are associated with differences in placental DNA methylation levels. Whole-genome DNA-methylation was measured using the Illumina's Infinium HumanMethylation450 BeadChip in the placenta of 668 newborns from the EDEN cohort. We designed an original strategy using a priori biological information to focus on candidate genes with a specific expression pattern in placenta (active or silent) combined with an agnostic epigenome-wide association study (EWAS). We used robust linear regression to identify CpGs and differentially methylated regions (DMR) associated with each exposure during short- and long-term time-windows. The candidate genes approach identified nine CpGs mapping to 9 genes associated with prenatal NO 2 and PM 10 exposure [false discovery rate (FDR) p < 0.05]. Among these, the methylation level of 2 CpGs located in ADORA2B remained significantly associated with NO 2 exposure during the 2nd trimester and whole pregnancy in the EWAS (FDR p < 0.05). EWAS further revealed associations between the environmental exposures under study and variations of DNA methylation of 4 other CpGs. We further identified 27 DMRs significantly (FDR p < 0.05) associated with air pollutants exposure and 13 DMRs with meteorological conditions. The methylation of ADORA2B, a gene whose expression was previously associated with hypoxia and pre-eclampsia, was consistently found here sensitive to atmospheric pollutants. In addition, air pollutants were associated to DMRs pointing towards genes previously implicated in

Effects of microplastic exposure on the body condition and behaviour of planktivorous reef fish (Acanthochromis polyacanthus)

PubMed Central

Hoogenboom, Mia O.

2018-01-01

The effect of a pollutant on the base of the food web can have knock-on effects for trophic structure and ecosystem functioning. In this study we assess the effect of microplastic exposure on juveniles of a planktivorous fish (Acanthochromis polyacanthus), a species that is widespread and abundant on Indo-Pacific coral reefs. Under five different plastic concentration treatments, with plastics the same size as the natural food particles (mean 2mm diameter), there was no significant effect of plastic exposure on fish growth, body condition or behaviour. The amount of plastics found in the gastro-intestinal (GI) tract was low, with a range of one to eight particles remaining in the gut of individual fish at the end of a 6-week plastic-exposure period, suggesting that these fish are able to detect and avoid ingesting microplastics in this size range. However, in a second experiment the number of plastics in the GI tract vastly increased when plastic particle size was reduced to approximately one quarter the size of the food particles, with a maximum of 2102 small (< 300μm diameter) particles present in the gut of individual fish after a 1-week plastic exposure period. Under conditions where food was replaced by plastic, there was a negative effect on the growth and body condition of the fish. These results suggest plastics could become more of a problem as they break up into smaller size classes, and that environmental changes that lead to a decrease in plankton concentrations combined with microplastic presence is likely have a greater influence on fish populations than microplastic presence alone. PMID:29494635

Effects of microplastic exposure on the body condition and behaviour of planktivorous reef fish (Acanthochromis polyacanthus).

PubMed

Critchell, Kay; Hoogenboom, Mia O

2018-01-01

The effect of a pollutant on the base of the food web can have knock-on effects for trophic structure and ecosystem functioning. In this study we assess the effect of microplastic exposure on juveniles of a planktivorous fish (Acanthochromis polyacanthus), a species that is widespread and abundant on Indo-Pacific coral reefs. Under five different plastic concentration treatments, with plastics the same size as the natural food particles (mean 2mm diameter), there was no significant effect of plastic exposure on fish growth, body condition or behaviour. The amount of plastics found in the gastro-intestinal (GI) tract was low, with a range of one to eight particles remaining in the gut of individual fish at the end of a 6-week plastic-exposure period, suggesting that these fish are able to detect and avoid ingesting microplastics in this size range. However, in a second experiment the number of plastics in the GI tract vastly increased when plastic particle size was reduced to approximately one quarter the size of the food particles, with a maximum of 2102 small (< 300μm diameter) particles present in the gut of individual fish after a 1-week plastic exposure period. Under conditions where food was replaced by plastic, there was a negative effect on the growth and body condition of the fish. These results suggest plastics could become more of a problem as they break up into smaller size classes, and that environmental changes that lead to a decrease in plankton concentrations combined with microplastic presence is likely have a greater influence on fish populations than microplastic presence alone.

Impact of age-related macular degeneration on object searches in realistic panoramic scenes.

PubMed

Thibaut, Miguel; Tran, Thi-Ha-Chau; Szaffarczyk, Sebastien; Boucart, Muriel

2018-05-01

This study investigated whether realistic immersive conditions with dynamic indoor scenes presented on a large, hemispheric panoramic screen covering 180° of the visual field improved the visual search abilities of participants with age-related macular degeneration (AMD). Twenty-one participants with AMD, 16 age-matched controls and 16 young observers were included. Realistic indoor scenes were presented on a panoramic five metre diameter screen. Twelve different objects were used as targets. The participants were asked to search for a target object, shown on paper before each trial, within a room composed of various objects. A joystick was used for navigation within the scene views. A target object was present in 24 trials and absent in 24 trials. The percentage of correct detection of the target, the percentage of false alarms (that is, the detection of the target when it was absent), the number of scene views explored and the search time were measured. The search time was slower for participants with AMD than for the age-matched controls, who in turn were slower than the young participants. The participants with AMD were able to accomplish the task with a performance of 75 per cent correct detections. This was slightly lower than older controls (79.2 per cent) while young controls were at ceiling (91.7 per cent). Errors were mainly due to false alarms resulting from confusion between the target object and another object present in the scene in the target-absent trials. The outcomes of the present study indicate that, under realistic conditions, although slower than age-matched, normally sighted controls, participants with AMD were able to accomplish visual searches of objects with high accuracy. © 2017 Optometry Australia.

SMART-DS: Synthetic Models for Advanced, Realistic Testing: Distribution

Science.gov Websites

statistical summary of the U.S. distribution systems World-class, high spatial/temporal resolution of solar Systems and Scenarios | Grid Modernization | NREL SMART-DS: Synthetic Models for Advanced , Realistic Testing: Distribution Systems and Scenarios SMART-DS: Synthetic Models for Advanced, Realistic

A full potential flow analysis with realistic wake influence for helicopter rotor airload prediction

NASA Technical Reports Server (NTRS)

Egolf, T. Alan; Sparks, S. Patrick

1987-01-01

A 3-D, quasi-steady, full potential flow solver was adapted to include realistic wake influence for the aerodynamic analysis of helicopter rotors. The method is based on a finite difference solution of the full potential equation, using an inner and outer domain procedure for the blade flowfield to accommodate wake effects. The nonlinear flow is computed in the inner domain region using a finite difference solution method. The wake is modeled by a vortex lattice using prescribed geometry techniques to allow for the inclusion of realistic rotor wakes. The key feature of the analysis is that vortices contained within the finite difference mesh (inner domain) were treated with a vortex embedding technique while the influence of the remaining portion of the wake (in the outer domain) is impressed as a boundary condition on the outer surface of the finite difference mesh. The solution procedure couples the wake influence with the inner domain solution in a consistent and efficient solution process. The method has been applied to both hover and forward flight conditions. Correlation with subsonic and transonic hover airload data is shown which demonstrates the merits of the approach.

Toxicological Evaluation of Realistic Emission Source Aerosols (TERESA): Introduction and overview

PubMed Central

Godleski, John J.; Rohr, Annette C.; Kang, Choong M.; Diaz, Edgar A.; Ruiz, Pablo A.; Koutrakis, Petros

2013-01-01

Determining the health impacts of sources and components of fine particulate matter (PM2.5) is an important scientific goal. PM2.5 is a complex mixture of inorganic and organic constituents that are likely to differ in their potential to cause adverse health outcomes. The Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) study focused on two PM sources—coal-fired power plants and mobile sources—and sought to investigate the toxicological effects of exposure to emissions from these sources. The set of papers published here document the power plant experiments. TERESA attempted to delineate health effects of primary particles, secondary (aged) particles, and mixtures of these with common atmospheric constituents. TERESA involved withdrawal of emissions from the stacks of three coal-fired power plants in the United States. The emissions were aged and atmospherically transformed in a mobile laboratory simulating downwind power plant plume processing. Toxicological evaluations were carried out in laboratory rats exposed to different emission scenarios with extensive exposure characterization. The approach employed in TERESA was ambitious and innovative. Technical challenges included the development of stack sampling technology that prevented condensation of water vapor from the power plant exhaust during sampling and transfer, while minimizing losses of primary particles; development and optimization of a photochemical chamber to provide an aged aerosol for animal exposures; development and evaluation of a denuder system to remove excess gaseous components; and development of a mobile toxicology laboratory. This paper provides an overview of the conceptual framework, design, and methods employed in the study. PMID:21639692

Feasibility study for a realistic training dedicated to radiological protection improvement

NASA Astrophysics Data System (ADS)

Courageot, Estelle; Reinald, Kutschera; Gaillard-Lecanu, Emmanuelle; Sylvie, Jahan; Riedel, Alexandre; Therache, Benjamin

2014-06-01

Any personnel involved in activities within the controlled area of a nuclear facility must be provided with appropriate radiological protection training. An evident purpose of this training is to know the regulation dedicated to workplaces where ionizing radiation may be present, in order to properly carry out the radiation monitoring, to use suitable protective equipments and to behave correctly if unexpected working conditions happen. A major difficulty of this training consist in having the most realistic reading from the monitoring devices for a given exposure situation, but without using real radioactive sources. A new approach is developed at EDF R&D for radiological protection training. This approach combines different technologies, in an environment representative of the workplace but geographically separated from the nuclear power plant: a training area representative of a workplace, a Man Machine Interface used by the trainer to define the source configuration and the training scenario, a geolocalization system, fictive radiation monitoring devices and a particle transport code able to calculate in real time the dose map due to the virtual sources. In a first approach, our real-time particles transport code, called Moderato, used only an attenuation low in straight line. To improve the realism further, we would like to switch a code based on the Monte Carlo transport of particles method like Geant 4 or MCNPX instead of Moderato. The aim of our study is the evaluation of the code in our application, in particular, the possibility to keep a real time response of our architecture.

Performance of honey bee colonies under a long-lasting dietary exposure to sublethal concentrations of the neonicotinoid insecticide thiacloprid.

PubMed

Siede, Reinhold; Faust, Lena; Meixner, Marina D; Maus, Christian; Grünewald, Bernd; Büchler, Ralph

2017-07-01

Substantial honey bee colony losses have occurred periodically in the last decades. The drivers for these losses are not fully understood. The influence of pests and pathogens are beyond dispute, but in addition, chronic exposure to sublethal concentrations of pesticides has been suggested to affect the performance of honey bee colonies. This study aims to elucidate the potential effects of a chronic exposure to sublethal concentrations (one realistic worst-case concentration) of the neonicotinoid thiacloprid to honey bee colonies in a three year replicated colony feeding study. Thiacloprid did not significantly affect the colony strength. No differences between treatment and control were observed for the mortality of bees, the infestation with the parasitic mite Varroa destructor and the infection levels of viruses. No colony losses occurred during the overwintering seasons. Furthermore, thiacloprid did not influence the constitutive expression of the immunity-related hymenoptaecin gene. However, upregulation of hymenoptaecin expression as a response to bacterial challenge was less pronounced in exposed bees than in control bees. Under field conditions, bee colonies are not adversely affected by a long-lasting exposure to sublethal concentrations of thiacloprid. No indications were found that field-realistic and higher doses exerted a biologically significant effect on colony performance. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Glucocorticoid exposure and fracture risk in a cohort of US patients with selected conditions.

PubMed

Balasubramanian, A; Wade, S W; Adler, R A; Saag, K; Pannacciulli, N; Curtis, J R

2018-06-20

We evaluated systemic glucocorticoid exposure and fracture among patients with newly-diagnosed inflammatory and immune-modulated conditions. Using administrative data, inception cohorts of RA, asthma/COPD, IBD, MS, lupus, and sarcoidosis patients age 18-64 years with benefits coverage ≥12 months before diagnosis (1/1/2005-12/31/2012) were followed to clinical fracture, cancer diagnosis, or 12/31/2012. Glucocorticoid users were new to therapy. Fracture incidence rates (IR) per 1,000 person-years were stratified by prednisone equivalent doses. Cox's proportional hazards models assessed risk by daily and cumulative dose, and by time since discontinuation, adjusted for baseline characteristics. Most patients (72% of 403,337) had glucocorticoid exposure; 52% were under age 50. IR (95% confidence intervals [CI]) of any osteoporotic fracture was elevated at doses < 5 mg/day, IR: 9.33 [7.29, 11.77] versus 0 mg/day, IR: 4.87 [4.72, 5.02]). Fracture rates were elevated at doses < 5 mg/day in patients < 50 years and those ≥ 50 years. In both age groups, fracture risk increased with increasing cumulative exposure, being approximately 2.5-fold higher at cumulative dose ≥ 5400 mg compared to < 675 mg. At ≥ 5400 mg, IR were 5.69 [4.32, 7.35] in patients < 50 years and 17.10 [14.97, 19.46] in older patients. Fracture risk decreased significantly within months following glucocorticoid discontinuation. In patients with a variety of inflammatory conditions, fracture risk increased at doses as low as < 5 mg/day. Risk increased with increasing cumulative exposure and decreased soon following glucocorticoid discontinuation. Trends were similar between patients older and younger than 50 years. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Time management: a realistic approach.

PubMed

Jackson, Valerie P

2009-06-01

Realistic time management and organization plans can improve productivity and the quality of life. However, these skills can be difficult to develop and maintain. The key elements of time management are goals, organization, delegation, and relaxation. The author addresses each of these components and provides suggestions for successful time management.

Mathematical modeling in realistic mathematics education

NASA Astrophysics Data System (ADS)

Riyanto, B.; Zulkardi; Putri, R. I. I.; Darmawijoyo

2017-12-01

The purpose of this paper is to produce Mathematical modelling in Realistics Mathematics Education of Junior High School. This study used development research consisting of 3 stages, namely analysis, design and evaluation. The success criteria of this study were obtained in the form of local instruction theory for school mathematical modelling learning which was valid and practical for students. The data were analyzed using descriptive analysis method as follows: (1) walk through, analysis based on the expert comments in the expert review to get Hypothetical Learning Trajectory for valid mathematical modelling learning; (2) analyzing the results of the review in one to one and small group to gain practicality. Based on the expert validation and students’ opinion and answers, the obtained mathematical modeling problem in Realistics Mathematics Education was valid and practical.

Computational dosimetry of induced electric fields during realistic movements in the vicinity of a 3 T MRI scanner

NASA Astrophysics Data System (ADS)

Laakso, Ilkka; Kännälä, Sami; Jokela, Kari

2013-04-01

Medical staff working near magnetic resonance imaging (MRI) scanners are exposed both to the static magnetic field itself and also to electric currents that are induced in the body when the body moves in the magnetic field. However, there are currently limited data available on the induced electric field for realistic movements. This study computationally investigates the movement induced electric fields for realistic movements in the magnetic field of a 3 T MRI scanner. The path of movement near the MRI scanner is based on magnetic field measurements using a coil sensor attached to a human volunteer. Utilizing realistic models for both the motion of the head and the magnetic field of the MRI scanner, the induced fields are computationally determined using the finite-element method for five high-resolution numerical anatomical models. The results show that the time-derivative of the magnetic flux density (dB/dt) is approximately linearly proportional to the induced electric field in the head, independent of the position of the head with respect to the magnet. This supports the use of dB/dt measurements for occupational exposure assessment. For the path of movement considered herein, the spatial maximum of the induced electric field is close to the basic restriction for the peripheral nervous system and exceeds the basic restriction for the central nervous system in the international guidelines. The 99th percentile electric field is a considerably less restrictive metric for the exposure than the spatial maximum electric field; the former is typically 60-70% lower than the latter. However, the 99th percentile electric field may exceed the basic restriction for dB/dt values that can be encountered during tasks commonly performed by MRI workers. It is also shown that the movement-induced eddy currents may reach magnitudes that could electrically stimulate the vestibular system, which could play a significant role in the generation of vertigo-like sensations reported

How effectively do horizontal and vertical response strategies of long-finned pilot whales reduce sound exposure from naval sonar?

PubMed

Wensveen, Paul J; von Benda-Beckmann, Alexander M; Ainslie, Michael A; Lam, Frans-Peter A; Kvadsheim, Petter H; Tyack, Peter L; Miller, Patrick J O

2015-05-01

The behaviour of a marine mammal near a noise source can modulate the sound exposure it receives. We demonstrate that two long-finned pilot whales both surfaced in synchrony with consecutive arrivals of multiple sonar pulses. We then assess the effect of surfacing and other behavioural response strategies on the received cumulative sound exposure levels and maximum sound pressure levels (SPLs) by modelling realistic spatiotemporal interactions of a pilot whale with an approaching source. Under the propagation conditions of our model, some response strategies observed in the wild were effective in reducing received levels (e.g. movement perpendicular to the source's line of approach), but others were not (e.g. switching from deep to shallow diving; synchronous surfacing after maximum SPLs). Our study exemplifies how simulations of source-whale interactions guided by detailed observational data can improve our understanding about motivations behind behaviour responses observed in the wild (e.g., reducing sound exposure, prey movement). Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of Realistic and Idealized Breathing Patterns in Computational Models of Airflow and Vapor Dosimetry in the Rodent Upper Respiratory Tract

PubMed Central

Jacob, Richard E.; Kuprat, Andrew P.; Einstein, Daniel R.; Corley, Richard A.

2016-01-01

Context Computational fluid dynamics (CFD) simulations of airflows coupled with physiologically-based pharmacokinetic (PBPK) modeling of respiratory tissue doses of airborne materials have traditionally used either steady-state inhalation or a sinusoidal approximation of the breathing cycle for airflow simulations despite their differences from normal breathing patterns. Objective Evaluate the impact of realistic breathing patterns, including sniffing, on predicted nasal tissue concentrations of a reactive vapor that targets the nose in rats as a case study. Materials and methods Whole-body plethysmography measurements from a free-breathing rat were used to produce profiles of normal breathing, sniffing, and combinations of both as flow inputs to CFD/PBPK simulations of acetaldehyde exposure. Results For the normal measured ventilation profile, modest reductions in time- and tissue depth-dependent areas under the curve (AUC) acetaldehyde concentrations were predicted in the wet squamous, respiratory, and transitional epithelium along the main airflow path, while corresponding increases were predicted in the olfactory epithelium, especially the most distal regions of the ethmoid turbinates, versus the idealized profile. The higher amplitude/frequency sniffing profile produced greater AUC increases over the idealized profile in the olfactory epithelium, especially in the posterior region. Conclusions The differences in tissue AUCs at known lesion-forming regions for acetaldehyde between normal and idealized profiles were minimal, suggesting that sinusoidal profiles may be used for this chemical and exposure concentration. However, depending upon the chemical, exposure system and concentration, and the time spent sniffing, the use of realistic breathing profiles—including sniffing—could become an important modulator for local tissue dose predictions. PMID:26986954

Mechanical stabilization of the Levitron's realistic model

NASA Astrophysics Data System (ADS)

Olvera, Arturo; De la Rosa, Abraham; Giordano, Claudia M.

2016-11-01

The stability of the magnetic levitation showed by the Levitron was studied by M.V. Berry as a six degrees of freedom Hamiltonian system using an adiabatic approximation. Further, H.R. Dullin found critical spin rate bounds where the levitation persists and R.F. Gans et al. offered numerical results regarding the initial conditions' manifold where this occurs. In the line of this series of works, first, we extend the equations of motion to include dissipation for a more realistic model, and then introduce a mechanical forcing to inject energy into the system in order to prevent the Levitron from falling. A systematic study of the flying time as a function of the forcing parameters is carried out which yields detailed bifurcation diagrams showing an Arnold's tongues structure. The stability of these solutions were studied with the help of a novel method to compute the maximum Lyapunov exponent called MEGNO. The bifurcation diagrams for MEGNO reproduce the same Arnold's tongue structure.

TOXICOLOGICAL EVALUATION OF REALISTIC EMISSIONS OF SOURCE AEROSOLS (TERESA): APPLICATION TO POWER PLANT-DERIVED PM2.5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annette Rohr

2006-03-01

TERESA (Toxicological Evaluation of Realistic Emissions of Source Aerosols) involves exposing laboratory rats to realistic coal-fired power plant and mobile source emissions to help determine the relative toxicity of these PM sources. There are three coal-fired power plants in the TERESA program; this report describes the results of fieldwork conducted at the first plant, located in the Upper Midwest. The project was technically challenging by virtue of its novel design and requirement for the development of new techniques. By examining aged, atmospherically transformed aerosol derived from power plant stack emissions, we were able to evaluate the toxicity of PM derivedmore » from coal combustion in a manner that more accurately reflects the exposure of concern than existing methodologies. TERESA also involves assessment of actual plant emissions in a field setting--an important strength since it reduces the question of representativeness of emissions. A sampling system was developed and assembled to draw emissions from the stack; stack sampling conducted according to standard EPA protocol suggested that the sampled emissions are representative of those exiting the stack into the atmosphere. Two mobile laboratories were then outfitted for the study: (1) a chemical laboratory in which the atmospheric aging was conducted and which housed the bulk of the analytical equipment; and (2) a toxicological laboratory, which contained animal caging and the exposure apparatus. Animal exposures were carried out from May-November 2004 to a number of simulated atmospheric scenarios. Toxicological endpoints included (1) pulmonary function and breathing pattern; (2) bronchoalveolar lavage fluid cytological and biochemical analyses; (3) blood cytological analyses; (4) in vivo oxidative stress in heart and lung tissue; and (5) heart and lung histopathology. Results indicated no differences between exposed and control animals in any of the endpoints examined. Exposure concentrations

Impact of body condition on influenza A virus infection dynamics in mallards following a secondary exposure

PubMed Central

Webb, Colleen T.; Wilson, Kenneth R.; Bentler, Kevin T.; Mooers, Nicole L.; Ellis, Jeremy W.; Root, J. Jeffrey; Franklin, Alan B.; Shriner, Susan A.

2017-01-01

Migratory waterfowl are often viewed as vehicles for the global spread of influenza A viruses (IAVs), with mallards (Anas platyrhynchos) implicated as particularly important reservoir hosts. The physical demands and energetic costs of migration have been shown to influence birds’ body condition; poorer body condition may suppress immune function and affect the course of IAV infection. Our study evaluated the impact of body condition on immune function and viral shedding dynamics in mallards naturally exposed to an H9 IAV, and then secondarily exposed to an H4N6 IAV. Mallards were divided into three treatment groups of 10 birds per group, with each bird’s body condition manipulated as a function of body weight by restricting food availability to achieve either a -10%, -20%, or control body weight class. We found that mallards exhibit moderate heterosubtypic immunity against an H4N6 IAV infection after an infection from an H9 IAV, and that body condition did not have an impact on shedding dynamics in response to a secondary exposure. Furthermore, body condition did not affect aspects of the innate and adaptive immune system, including the acute phase protein haptoglobin, heterophil/lymphocyte ratios, and antibody production. Contrary to recently proposed hypotheses and some experimental evidence, our data do not support relationships between body condition, infection and immunocompetence following a second exposure to IAV in mallards. Consequently, while annual migration may be a driver in the maintenance and spread of IAVs, the energetic demands of migration may not affect susceptibility in mallards. PMID:28423047

Impact of body condition on influenza A virus infection dynamics in mallards following a secondary exposure.

PubMed

Dannemiller, Nicholas G; Webb, Colleen T; Wilson, Kenneth R; Bentler, Kevin T; Mooers, Nicole L; Ellis, Jeremy W; Root, J Jeffrey; Franklin, Alan B; Shriner, Susan A

2017-01-01

Migratory waterfowl are often viewed as vehicles for the global spread of influenza A viruses (IAVs), with mallards (Anas platyrhynchos) implicated as particularly important reservoir hosts. The physical demands and energetic costs of migration have been shown to influence birds' body condition; poorer body condition may suppress immune function and affect the course of IAV infection. Our study evaluated the impact of body condition on immune function and viral shedding dynamics in mallards naturally exposed to an H9 IAV, and then secondarily exposed to an H4N6 IAV. Mallards were divided into three treatment groups of 10 birds per group, with each bird's body condition manipulated as a function of body weight by restricting food availability to achieve either a -10%, -20%, or control body weight class. We found that mallards exhibit moderate heterosubtypic immunity against an H4N6 IAV infection after an infection from an H9 IAV, and that body condition did not have an impact on shedding dynamics in response to a secondary exposure. Furthermore, body condition did not affect aspects of the innate and adaptive immune system, including the acute phase protein haptoglobin, heterophil/lymphocyte ratios, and antibody production. Contrary to recently proposed hypotheses and some experimental evidence, our data do not support relationships between body condition, infection and immunocompetence following a second exposure to IAV in mallards. Consequently, while annual migration may be a driver in the maintenance and spread of IAVs, the energetic demands of migration may not affect susceptibility in mallards.

A realistic in vitro exposure revealed seasonal differences in (pro-)inflammatory effects from ambient air in Fribourg, Switzerland.

PubMed

Bisig, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara

2018-01-01

Ambient air pollutant levels vary widely in space and time, therefore thorough local evaluation of possible effects is needed. In vitro approaches using lung cell cultures grown at the air-liquid interface and directly exposed to ambient air can offer a reliable addition to animal experimentations and epidemiological studies. To evaluate the adverse effects of ambient air in summer and winter a multi-cellular lung model (16HBE14o-, macrophages, and dendritic cells) was exposed in a mobile cell exposure system. Cells were exposed on up to three consecutive days each 12 h to ambient air from Fribourg, Switzerland, during summer and winter seasons. Higher particle number, particulate matter mass, and nitrogen oxide levels were observed in winter ambient air compared to summer. Good cell viability was seen in cells exposed to summer air and short-term winter air, but cells exposed three days to winter air were compromised. Exposure of summer ambient air revealed no significant upregulation of oxidative stress or pro-inflammatory genes. On the opposite, the winter ambient air exposure led to an increased oxidative stress after two exposure days, and an increase in three assessed pro-inflammatory genes already after 12 h of exposure. We found that even with a short exposure time of 12 h adverse effects in vitro were observed only during exposure to winter but not summer ambient air. With this work we have demonstrated that our simple, fast, and cost-effective approach can be used to assess (adverse) effects of ambient air.

Acute nonhypothermic exposure to cold impedes motor skill performance in video gaming compared to thermo-neutral and hot conditions.

PubMed

Edwards, Andrew M; Crowther, Robert G; Morton, R Hugh; Polman, Remco C

2011-02-01

The study examined whether or not acute exposure to unfamiliar hot or cold conditions impairs performance of highly skilled coordinative activities and whether prior physical self-efficacy beliefs were associated with task completion. Nineteen volunteers completed both Guitar Hero and Archery activities as a test battery using the Nintendo Wii console in cold (2 degrees C), neutral (20 degrees C), and hot (38 degrees C) conditions. Participants all completed physical self-efficacy questionnaires following experimental familiarization. Performances of both Guitar Hero and Archery significantly decreased in the cold compared with the neutral condition. The cold trial was also perceived as the condition requiring both greater concentration and effort. There was no association between performance and physical self-efficacy. Performance of these coordinative tasks was compromised by acute (nonhypothermic) exposure to cold; the most likely explanation is that the cold condition presented a greater challenge to attentional processes as a form of environmental distraction.

Results of extended plant tests using more realistic exposure scenarios for improving environmental risk assessment of veterinary pharmaceuticals.

PubMed

Richter, Elisabeth; Berkner, Silvia; Ebert, Ina; Förster, Bernhard; Graf, Nadin; Herrchen, Monika; Kühnen, Ute; Römbke, Jörg; Simon, Markus

2016-01-01

Residues of veterinary medicinal products (VMPs) enter the environment via application of manure onto agricultural areas where in particular antibiotics can cause phytotoxicity. Terrestrial plant tests according to OECD guideline 208 are part of the environmental risk assessment of VMPs. However, this standard approach might not be appropriate for VMPs which form non-extractable residues or transformation products in manure and manure-amended soil. Therefore, a new test design with a more realistic exposure scenario via manure application is needed. This paper presents an extended plant test and its experimental verification with the veterinary antibiotics florfenicol and tylosin tartrate. With each substance, plant tests with four different types of application were conducted: standard tests according to OECD 208 and three tests with application of test substance via spiked manure either without storage, aerobically incubated, or anaerobically incubated for different time periods. In standard tests, the lowest NOEC was <0.06 mg/kg dry soil for florfenicol and 16.0 mg/kg dry soil for tylosin tartrate. Pre-tests showed that plant growth was not impaired at 22-g fresh manure/kg dry soil, which therefore was used for the final tests. The application of the test substances via freshly spiked as well as via aerobically incubated manure had no significant influence on the test results. Application of florfenicol via anaerobically incubated manure increased the EC10 by a factor up to 282 and 540 for half-maximum and for maximum incubation period, respectively. For tylosin tartrate, this factor amounted to 64 at half-maximum and 61 at maximum incubation period. The reduction of phytotoxicity was generally stronger when using cattle manure than pig manure and particularly in tests with cattle manure phytotoxicity decreased over the incubation period. The verification of the extended plant test showed that seedling emergence and growth are comparable to a standard OECD

Retrospective estimation of the electric and magnetic field exposure conditions in in vitro experimental reports reveal considerable potential for uncertainty.

PubMed

Portelli, Lucas A; Falldorf, Karsten; Thuróczy, György; Cuppen, Jan

2018-04-01

Experiments on cell cultures exposed to extremely low frequency (ELF, 3-300 Hz) magnetic fields are often subject to multiple sources of uncertainty associated with specific electric and magnetic field exposure conditions. Here we systemically quantify these uncertainties based on exposure conditions described in a group of bioelectromagnetic experimental reports for a representative sampling of the existing literature. The resulting uncertainties, stemming from insufficient, ambiguous, or erroneous description, design, implementation, or validation of the experimental methods and systems, were often substantial enough to potentially make any successful reproduction of the original experimental conditions difficult or impossible. Without making any assumption about the true biological relevance of ELF electric and magnetic fields, these findings suggest another contributing factor which may add to the overall variability and irreproducibility traditionally associated with experimental results of in vitro exposures to low-level ELF magnetic fields. Bioelectromagnetics. 39:231-243, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Impact of smoking on in-vehicle fine particle exposure during driving

NASA Astrophysics Data System (ADS)

Sohn, Hongji; Lee, Kiyoung

2010-09-01

Indoor smoking ban in public places can reduce secondhand smoke (SHS) exposure. However, smoking in cars and homes has continued. The purpose of this study was to assess particulate matter less than 2.5 μm (PM 2.5) concentration in moving cars with different window opening conditions. The PM 2.5 level was measured by an aerosol spectrometer inside and outside moving cars simultaneously, along with ultrafine particle (UFP) number concentration, speed, temperature and humidity inside cars. Two sport utility vehicles were used. Three different ventilation conditions were evaluated by up to 20 repeated experiments. In the pre-smoking phase, average in-vehicle PM 2.5 concentrations were 16-17 μg m -3. Regardless of different window opening conditions, the PM 2.5 levels promptly increased when smoking occurred and decreased after cigarette was extinguished. Although only a single cigarette was smoked, the average PM 2.5 levels were 506-1307 μg m -3 with different window opening conditions. When smoking was ceased, the average PM 2.5 levels for 15 min were several times higher than the US National Ambient Air Quality Standard of 35 μg m -3. It took longer than 10 min to reach the level of the pre-smoking phase. Although UFP levels had a similar temporal profile of PM 2.5, the increased levels during the smoking phase were relatively small. This study demonstrated that the SHS exposure in cars with just a single cigarette being smoked could exceed the US EPA NAAQS under realistic window opening conditions. Therefore, the findings support the need for public education against smoking in cars and advocacy for a smoke-free car policy.

Five year ground exposure of composite materials used on the Bell Model 206L flight service evaluation

NASA Technical Reports Server (NTRS)

Baker, Donald J.

1989-01-01

Part of the results of a U.S. Army/NASA-Langley sponsored research program to establish the long term-term effects of realistic ground based exposure on advanced composite materials is presented. Residual strengths and moisture absorption as a function of exposure time and exposure location are reported for four different composite material systems that were exposed for five years on the North American Continent.

Exposure to Free-Play Modes in Simulated Online Gaming Increases Risk-Taking in Monetary Gambling.

PubMed

Frahn, Tahnee; Delfabbro, Paul; King, Daniel L

2015-12-01

This study examined the behavioral effects of practice modes in simulated slot machine gambling. A sample of 128 participants predominantly aged 18-24 years were randomly allocated to 1 of 4 pre-exposure conditions: control (no practice), standard 90% return to player, inflated return to player and inflated return with pop-up messages. Participants in all conditions engaged in monetary gambling using a realistic online simulation of a slot machine. As predicted, the results showed that those players exposed to inflated or 'profit' demonstration modes placed significantly higher bets in the real-play mode as compared to the other groups. However, the groups did not differ in relation to how long they persisted in the real-play mode. Pop-up messages had no significant effect on monetary gambling behavior. The results of this study confirm that exposure to inflated practice or "demo" modes lead to short-term increases in risk-taking. These findings highlight the need for careful regulation and monitoring of internet gambling sites, as well as further research on the potential risks of simulated gambling activities for vulnerable segments of the gambling population.

The effects of intermittent exposure to low-pH and low-oxygen conditions on survival and growth of juvenile red abalone

NASA Astrophysics Data System (ADS)

Kim, T. W.; Barry, J. P.; Micheli, F.

2013-11-01

Exposure of nearshore animals to hypoxic, low-pH waters upwelled from below the continental shelf and advected near the coast may be stressful to marine organisms and lead to impaired physiological performance. We mimicked upwelling conditions in the laboratory and tested the effect of fluctuating exposure to water with low-pH and/or low-oxygen levels on the mortality and growth of juvenile red abalone (Haliotis rufescens, shell length 5-10 mm). Mortality rates of juvenile abalone exposed to low-pH (7.5, total scale) and low-O2 (40% saturation, mg L-1) conditions for periods of 3 to 6 h every 3-5 days over 2 weeks did not differ from those exposed to control conditions (O2: 100% saturation, 12 mg L-1; pH 8.0). However, when exposure was extended to 24 h, twice over a 15-day period, juveniles experienced 5-20% higher mortality in the low-oxygen treatments compared to control conditions. Growth rates were reduced significantly when juveniles were exposed to low-oxygen and low-pH treatments. Furthermore, individual variation of growth rate increased when juveniles were exposed simultaneously to low-pH and low-O2 conditions. These results indicate that prolonged exposure to low-oxygen levels is detrimental for the survival of red abalone, whereas pH is a crucial factor for their growth. However, the high individual variation in growth rate under low levels of both pH and oxygen suggests that cryptic phenotypic plasticity may promote resistance to prolonged upwelling conditions by a portion of the population.

Realistic nurse-led policy implementation, optimization and evaluation: novel methodological exemplar.

PubMed

Noyes, Jane; Lewis, Mary; Bennett, Virginia; Widdas, David; Brombley, Karen

2014-01-01

To report the first large-scale realistic nurse-led implementation, optimization and evaluation of a complex children's continuing-care policy. Health policies are increasingly complex, involve multiple Government departments and frequently fail to translate into better patient outcomes. Realist methods have not yet been adapted for policy implementation. Research methodology - Evaluation using theory-based realist methods for policy implementation. An expert group developed the policy and supporting tools. Implementation and evaluation design integrated diffusion of innovation theory with multiple case study and adapted realist principles. Practitioners in 12 English sites worked with Consultant Nurse implementers to manipulate the programme theory and logic of new decision-support tools and care pathway to optimize local implementation. Methods included key-stakeholder interviews, developing practical diffusion of innovation processes using key-opinion leaders and active facilitation strategies and a mini-community of practice. New and existing processes and outcomes were compared for 137 children during 2007-2008. Realist principles were successfully adapted to a shorter policy implementation and evaluation time frame. Important new implementation success factors included facilitated implementation that enabled 'real-time' manipulation of programme logic and local context to best-fit evolving theories of what worked; using local experiential opinion to change supporting tools to more realistically align with local context and what worked; and having sufficient existing local infrastructure to support implementation. Ten mechanisms explained implementation success and differences in outcomes between new and existing processes. Realistic policy implementation methods have advantages over top-down approaches, especially where clinical expertise is low and unlikely to diffuse innovations 'naturally' without facilitated implementation and local optimization. © 2013

Personal Air Pollution Exposure Monitoring using Low Cost Sensors in Chennai City

NASA Astrophysics Data System (ADS)

Reddy Yasa, Pavan; Shiva, Nagendra S. N.

2016-04-01

Air quality in many cities is deteriorating due to rapid urbanization and motorization. In the past, most of the health impacts studies in the urban areas have considered stationary air quality monitoring station data for health impact assessment. Since, there exist a spatial and temporal variation of air quality because of rapid change in land use pattern and complex interaction between emission sources and meteorological conditions, the human exposure assessment using stationary data may not provide realistic information. In such cases low cost sensors monitoring is viable in providing both spatial and temporal variations of air pollutant concentrations. In the present study an attempt has been made to use low cost sensor for monitoring the personal exposure to the two criteria pollutants CO and PM2.5 at 3 different locations of Chennai city. Maximum and minimum concentrations of CO and PM2.5 were found to be 5.4ppm, 0.8ppm and 534.8μg/m3, 1.9μg/m3 respectively. Results showed high concentrations near the intersection and low concentrations in the straight road.

Linking Different Exposure Patterns to Internal Lung Dose for Heterogeneous Ambient Aerosols

EPA Science Inventory

Particulate matter (PM) in the ambient air is a complex mixture of particles with different sizes and chemical compositions. Because potential health effects are known to be different for different size particles, specific dose of size-fractionated PM under realistic exposure con...

Convective aggregation in realistic convective-scale simulations

NASA Astrophysics Data System (ADS)

Holloway, Christopher E.

2017-06-01

To investigate the real-world relevance of idealized-model convective self-aggregation, five 15 day cases of real organized convection in the tropics are simulated. These include multiple simulations of each case to test sensitivities of the convective organization and mean states to interactive radiation, interactive surface fluxes, and evaporation of rain. These simulations are compared to self-aggregation seen in the same model configured to run in idealized radiative-convective equilibrium. Analysis of the budget of the spatial variance of column-integrated frozen moist static energy shows that control runs have significant positive contributions to organization from radiation and negative contributions from surface fluxes and transport, similar to idealized runs once they become aggregated. Despite identical lateral boundary conditions for all experiments in each case, systematic differences in mean column water vapor (CWV), CWV distribution shape, and CWV autocorrelation length scale are found between the different sensitivity runs, particularly for those without interactive radiation, showing that there are at least some similarities in sensitivities to these feedbacks in both idealized and realistic simulations (although the organization of precipitation shows less sensitivity to interactive radiation). The magnitudes and signs of these systematic differences are consistent with a rough equilibrium between (1) equalization due to advection from the lateral boundaries and (2) disaggregation due to the absence of interactive radiation, implying disaggregation rates comparable to those in idealized runs with aggregated initial conditions and noninteractive radiation. This points to a plausible similarity in the way that radiation feedbacks maintain aggregated convection in both idealized simulations and the real world.