Science.gov

Sample records for disruption cascading effects

  1. Market disruption, cascading effects, and economic recovery:a life-cycle hypothesis model.

    SciTech Connect

    Sprigg, James A.

    2004-11-01

    This paper builds upon previous work [Sprigg and Ehlen, 2004] by introducing a bond market into a model of production and employment. The previous paper described an economy in which households choose whether to enter the labor and product markets based on wages and prices. Firms experiment with prices and employment levels to maximize their profits. We developed agent-based simulations using Aspen, a powerful economic modeling tool developed at Sandia, to demonstrate that multiple-firm economies converge toward the competitive equilibria typified by lower prices and higher output and employment, but also suffer from market noise stemming from consumer churn. In this paper we introduce a bond market as a mechanism for household savings. We simulate an economy of continuous overlapping generations in which each household grows older in the course of the simulation and continually revises its target level of savings according to a life-cycle hypothesis. Households can seek employment, earn income, purchase goods, and contribute to savings until they reach the mandatory retirement age; upon retirement households must draw from savings in order to purchase goods. This paper demonstrates the simultaneous convergence of product, labor, and savings markets to their calculated equilibria, and simulates how a disruption to a productive sector will create cascading effects in all markets. Subsequent work will use similar models to simulate how disruptions, such as terrorist attacks, would interplay with consumer confidence to affect financial markets and the broader economy.

  2. The new concept of the Disruption Index (DI) as an indicator to measure cascading effects in urban areas

    NASA Astrophysics Data System (ADS)

    Oliveira, C. S.; Ferreira, M. A.

    2015-12-01

    Apart from the loss of lives, injuries and homeless resulting from an earthquake, not only the economy and physical landscape are altered, but also the lives of citizens and their places of work are dramatically altered. If critical services and functions are disrupted for more than a reasonable time period, consequences can be severe. All communities are at risk and face potential disaster, if unprepared. The Disruption Index (DI) is a tool that allows the representation of a complex, multidimensional, situation in a concise and easier way, providing institutions and communities with a way to identify the global earthquake impact in a geographical area, the elements at risk, and the means to reduce it. Understanding how the loss and cascading effects across a number of areas might be correlated during a single earthquake is critical to evaluate risk. The application of this tool, prior-to a catastrophe, assumes a huge importance for earthquake risk professionals and planners to understand their impacts and to start building earthquake resilient cities. Post-to an event, this tool provides an assessment of its extent and impact considering the propagation effects, developed in a Geographic Information System (GIS) environment. The DI was already tested, calibrated after several earthquakes and applied in Portugal, Italy, Spain and Iceland. The next step in this research is to implement this tool directly into web portals or websites as well as PAGER or GDACS platforms to: - Rapidly assess an earthquake impact in a region following significant events. Nowadays the institutions used the shake maps; it's an important tool but cannot reflect the impact on livelihoods and the cascade effects. The DI maps can be used by state and local organizations, both public and private, for post-earthquake response and recovery, public and scientific information.

  3. Endocrine Effects of Circadian Disruption.

    PubMed

    Bedrosian, Tracy A; Fonken, Laura K; Nelson, Randy J

    2016-01-01

    Disruption of circadian rhythms, provoked by artificial lighting at night, inconsistent sleep-wake schedules, and transmeridian air travel, is increasingly prevalent in modern society. Desynchrony of biological rhythms from environmental light cycles has dramatic consequences for human health. In particular, disrupting homeostatic oscillations in endocrine tissues and the hormones that these tissues regulate can have cascading effects on physiology and behavior. Accumulating evidence suggests that chronic disruption of circadian organization of endocrine function may lead to metabolic, reproductive, sleep, and mood disorders. This review discusses circadian control of endocrine systems and the consequences of distorting rhythmicity of these systems. PMID:26208951

  4. Cascading Effects Following Intervention

    PubMed Central

    Patterson, Gerald R.; Forgatch, Marion S.; DeGarmo, David S.

    2010-01-01

    Four different sources for cascade effects were examined using 9-year process and outcome data from a randomized controlled trial (RCT) of a preventive intervention using Parent Management Training – Oregon Model (PMTO™). The social interaction learning (SIL) model of child antisocial behavior serves as one basis for predicting change. A second source addresses the issue of comorbid relationships among clinical diagnoses. The third source, collateral changes, describes events in which changes in one family member correlate with changes in another. The fourth component is based on the long-term effects of reducing coercion and increasing positive interpersonal processes within the family. New findings from the 9-year follow-up show that mothers experienced benefits as measured by standard of living (i.e., income, occupation, education, and financial stress) and frequency of police arrests. It is assumed that PMTO reduces the level of coercion, which sets the stage for a massive increase in positive social interaction. In effect, PMTO alters the family environment and thereby opens doors to healthy new social environments. PMID:20883592

  5. Temperament Pathways to Childhood Disruptive Behavior and Adolescent Substance Abuse: Testing a Cascade Model

    ERIC Educational Resources Information Center

    Martel, Michelle M.; Pierce, Laura; Nigg, Joel T.; Jester, Jennifer M.; Adams, Kenneth; Puttler, Leon I.; Buu, Anne; Fitzgerald, Hiram; Zucker, Robert A.

    2009-01-01

    Temperament traits may increase risk for developmental psychopathology like Attention-Deficit/Hyperactivity Disorder (ADHD) and disruptive behaviors during childhood, as well as predisposing to substance abuse during adolescence. In the current study, a cascade model of trait pathways to adolescent substance abuse was examined. Component…

  6. HELIUM EFFECTS ON DISPLACEMENT CASCADE IN TUNGSTEN

    SciTech Connect

    Setyawan, Wahyu; Nandipati, Giridhar; Roche, Kenneth J.; Heinisch, Howard L.; Kurtz, Richard J.; Wirth, Brian D.

    2013-09-30

    Molecular dynamics (MD) simulations were performed to investigate He effects on displacement cascades in W. Helium content, proportion of interstitial and substitutional He and temperature were varied to reveal the various effects. The effect of interstitial He on the number of self-interstitial atoms (SIAs) produced during cascade damage appears to be insignificant. However, interstitial He tends to fill a vacancy (V). Nevertheless, this process is less favorable than SIA-V recombination particularly when excess SIAs are present before a cascade. The efficiency of He filling and SIA-V recombination increases as temperature increases due to increased point defect mobility. Likewise, substitutional He is more susceptible to displacement during a collision cascade than W. This susceptibility increases towards higher temperatures. Consequently, the number of surviving V is governed by the interplay between displaced substitutional He and SIA-V recombination. The temperature dependence of these processes results in a minimum number of V reached at an intermediate temperature.

  7. Network effects, cascades and CCP interoperability

    NASA Astrophysics Data System (ADS)

    Feng, Xiaobing; Hu, Haibo; Pritsker, Matthew

    2014-03-01

    To control counterparty risk, financial regulations such as the Dodd Frank Act are increasingly requiring standardized derivatives trades to be cleared by central counterparties (CCPs). It is anticipated that in the near-term future, CCPs across the world will be linked through interoperability agreements that facilitate risk-sharing but also serve as a conduit for transmitting shocks. This paper theoretically studies a network with CCPs that are linked through interoperability arrangements, and studies the properties of the network that contribute to cascading failures. The magnitude of the cascading is theoretically related to the strength of network linkages, the size of the network, the logistic mapping coefficient, a stochastic effect and CCP's defense lines. Simulations indicate that larger network effects increase systemic risk from cascading failures. The size of the network N raises the threshold value of shock sizes that are required to generate cascades. Hence, the larger the network, the more robust it will be.

  8. Disruption of genes in the retinoid cascade may explain the microscopic neuroblastoma in a fetus with de novo unbalanced translocation

    SciTech Connect

    Goodman, A.B.

    1995-03-13

    The microscopic neuroblastoma in a fetus with de novo unbalanced translocation (3;10)(q21;q26) may be explained as the disruption of genes in the retinoid cascade, rather than simply a two-hit hypothesis for the development of tumor cells. 5 refs.

  9. Prediction and Control of Network Cascade: Example of Power Grid or Networking Adaptability from WMD Disruption and Cascading Failures

    SciTech Connect

    Chertkov, Michael

    2012-07-24

    The goal of the DTRA project is to develop a mathematical framework that will provide the fundamental understanding of network survivability, algorithms for detecting/inferring pre-cursors of abnormal network behaviors, and methods for network adaptability and self-healing from cascading failures.

  10. Environmental solid particle effects on compressor cascade performance

    NASA Technical Reports Server (NTRS)

    Tabakoff, W.; Balan, C.

    1982-01-01

    The effect of suspended solid particles on the performance of the compressor cascade was investigated experimentally in a specially built cascade tunnel, using quartz sand particles. The cascades were made of NACA 65(10)10 airfoils. Three cascades were tested, one accelerating cascade and two diffusing cascades. The theoretical analysis assumes inviscid and incompressible two dimensional flow. The momentum exchange between the fluid and the particle is accounted for by the interphase force terms in the fluid momentum equation. The modified fluid phase momentum equations and the continuity equation are reduced to the conventional stream function vorticity formulation. The method treats the fluid phase in the Eulerian system and the particle phase in Lagrangian system. The experimental results indicate a small increase in the blade surface static pressures, while the theoretical results indicate a small decrease. The theoretical analysis, also predicts the loss in total pressure associated with the particulate flow through the cascade.

  11. Cascading ecological effects of eliminating fishery discards.

    PubMed

    Heath, Michael R; Cook, Robin M; Cameron, Angus I; Morris, David J; Speirs, Douglas C

    2014-01-01

    Discarding by fisheries is perceived as contrary to responsible harvesting. Legislation seeking to end the practice is being introduced in many jurisdictions. However, discarded fish are food for a range of scavenging species; so, ending discarding may have ecological consequences. Here we investigate the sensitivity of ecological effects to discarding policies using an ecosystem model of the North Sea--a region where 30-40% of trawled fish catch is currently discarded. We show that landing the entire catch while fishing as usual has conservation penalties for seabirds, marine mammals and seabed fauna, and no benefit to fish stocks. However, combining landing obligations with changes in fishing practices to limit the capture of unwanted fish results in trophic cascades that can benefit birds, mammals and most fish stocks. Our results highlight the importance of considering the broader ecosystem consequences of fishery management policy, since species interactions may dissipate or negate intended benefits. PMID:24820200

  12. Cascading ecological effects of eliminating fishery discards

    PubMed Central

    Heath, Michael R.; Cook, Robin M.; Cameron, Angus I.; Morris, David J.; Speirs, Douglas C.

    2014-01-01

    Discarding by fisheries is perceived as contrary to responsible harvesting. Legislation seeking to end the practice is being introduced in many jurisdictions. However, discarded fish are food for a range of scavenging species; so, ending discarding may have ecological consequences. Here we investigate the sensitivity of ecological effects to discarding policies using an ecosystem model of the North Sea—a region where 30–40% of trawled fish catch is currently discarded. We show that landing the entire catch while fishing as usual has conservation penalties for seabirds, marine mammals and seabed fauna, and no benefit to fish stocks. However, combining landing obligations with changes in fishing practices to limit the capture of unwanted fish results in trophic cascades that can benefit birds, mammals and most fish stocks. Our results highlight the importance of considering the broader ecosystem consequences of fishery management policy, since species interactions may dissipate or negate intended benefits. PMID:24820200

  13. Thyroid effects of endocrine disrupting chemicals.

    PubMed

    Boas, Malene; Feldt-Rasmussen, Ulla; Main, Katharina M

    2012-05-22

    In recent years, many studies of thyroid-disrupting effects of environmental chemicals have been published. Of special concern is the exposure of pregnant women and infants, as thyroid disruption of the developing organism may have deleterious effects on neurological outcome. Chemicals may exert thyroid effects through a variety of mechanisms of action, and some animal experiments and in vitro studies have focused on elucidating the mode of action of specific chemical compounds. Long-term human studies on effects of environmental chemicals on thyroid related outcomes such as growth and development are still lacking. The human exposure scenario with life long exposure to a vast mixture of chemicals in low doses and the large physiological variation in thyroid hormone levels between individuals render human studies very difficult. However, there is now reasonably firm evidence that PCBs have thyroid-disrupting effects, and there is emerging evidence that also phthalates, bisphenol A, brominated flame retardants and perfluorinated chemicals may have thyroid disrupting properties. PMID:21939731

  14. Disruption effects on the beam size measurement

    SciTech Connect

    Raimondi, P.; Decker, F.J.; Chen, P.

    1995-06-01

    At the SLC Final Focus with higher currents and smaller beam sizes, the disruption parameter D{sub y} is close to one and so the pinch effect should produce a luminosity enhancement. Since a flat beam-beam function is fit to deflection scan data to measure the beam size, disruption can affect the measurement. Here the authors discuss the quantitative effects of disruption for typical SLC beam parameters. With 3.5 10{sup 10} particles per pulse, bunch length of 0.8 mm and beam sizes of 2.1 {mu}m horizontally and 0.55 {mu}m vertically, the measured vertical size can be as much as 25% bigger than the real one. Furthermore during the collision the spot size actually decrease, producing an enhancement factor H{sub D} of about 1.25. This would yield to a true luminosity which is 1.6 times that which is estimated from the beam-beam deflection fit.

  15. Can salinity trigger cascade effects on streams? A mesocosm approach.

    PubMed

    Cañedo-Argüelles, Miguel; Sala, Miquel; Peixoto, Gabriela; Prat, Narcís; Faria, Melissa; Soares, Amadeu M V M; Barata, Carlos; Kefford, Ben

    2016-01-01

    Human activities have greatly increased the salt concentration of the world's rivers, and this might be amplified by water scarcity in the future. While the lethal effects of salinity have been documented for a wide variety of stream invertebrates, the sub-lethal effects (i.e. changes in biological condition without mortality) are not deeply understood yet. One important sub-lethal effect that has yet to be investigated is changes in predation efficiency, which could trigger cascade effects associated to the abundance of herbivorous invertebrates that control algae biomass. In this study we combined the use of biomarkers with community-level data in a stream mesocosm to evaluate the potential cascade effect of increased salinity on the trophic food web. Both predation and salt treatments had an effect on the aquatic invertebrate abundance, richness and community composition. The presence of predators had a clear cascade effect, it reduced herbivorous invertebrate abundance and richness leading to higher chlorophyll a concentrations. The salt treatment significantly reduced taxa richness, but only in the gravel bed. The predators were significantly stressed by salt addition, as shown by the different analyzed biomarkers. Concordantly, in the presence of predators, Tanytarsini registered higher abundances and chlorophyll a showed a lower concentration when salt was added. However, none of these changes was significant. Therefore, although salt addition significantly stressed Dina lineata, our results suggest that a longer exposure time is needed to fully capture cascading effects (e.g. a decrease in chlorophyll a due to a relaxation of predation on herbivorous invertebrates). We suggest that the potential cascade effects of salinization need to be evaluated when addressing the impacts of water scarcity (as caused by climate change and increasing water demand) on river ecosystems, since flow reductions will lead to higher salt concentrations. PMID:25818391

  16. Calcium-Ask1-MKK7-JNK2-c-Src Signaling Cascade Mediates Disruption of Intestinal Epithelial Tight Junctions by Dextran Sulfate Sodium

    PubMed Central

    Samak, Geetha; Chaudhry, Kamaljit K.; Gangwar, Ruchika; Narayanan, Damodaran; Jaggar, Jonathan H.; Rao, RadhaKrishna

    2015-01-01

    Disruption of intestinal epithelial tight junctions is an important event in the pathogenesis of ulcerative colitis. Dextran sodium sulfate (DSS) induces colitis in mice with the symptoms similar to ulcerative colitis. However, the mechanism of DSS-induced colitis is unknown. We investigated the mechanism of DSS-induced disruption of intestinal epithelial tight junctions and barrier dysfunction in Caco-2 cell monolayers in vitro and mouse colon in vivo. DSS treatment resulted in disruption of tight junctions, adherens junctions and actin cytoskeleton leading to barrier dysfunction in Caco-2 cell monolayers. DSS induced a rapid activation of c-jun N-terminal kinase (JNK), and the inhibition or knockdown of JNK2 attenuated DSS-induced tight junction disruption and barrier dysfunction. In mice, DSS administration for 4 days caused redistribution of tight junction and adherens junction proteins from the epithelial junctions, which was blocked by JNK inhibitor. In Caco-2 cell monolayers, DSS increased intracellular Ca2+ concentration, and depletion of intracellular Ca2+ by BAPTA or thapsigargin attenuated DSS-induced JNK activation, tight junction disruption and barrier dysfunction. Knockdown of Ask1 or MKK7 blocked DSS-induced tight junction disruption and barrier dysfunction. DSS activated c-Src by a Ca2+ and JNK-dependent mechanism. Inhibition of Src kinase activity or knockdown of c-Src blocked DSS-induced tight junction disruption and barrier dysfunction. DSS increased Tyr-phosphorylation of occludin, ZO-1, E-cadherin and β-catenin. SP600125 abrogated DSS-induced Tyr-phosphorylation of junctional proteins. Recombinant JNK2 induced threonine phosphorylation and auto phosphorylation of c-Src. This study demonstrates that Ca2+-Ask1-MKK7-JNK2-cSrc signaling cascade mediates DSS-induced tight junction disruption and barrier dysfunction. PMID:25377781

  17. The Lehman Brothers effect and bankruptcy cascades

    NASA Astrophysics Data System (ADS)

    Sieczka, P.; Sornette, D.; Holyst, J. A.

    2011-08-01

    Inspired by the bankruptcy of Lehman Brothers and its consequences on the global financial system, we develop a simple model in which the Lehman default event is quantified as having an almost immediate effect in worsening the credit worthiness of all financial institutions in the economic network. In our stylized description, all properties of a given firm are captured by its effective credit rating, which follows a simple dynamics of co-evolution with the credit ratings of the other firms in our economic network. The dynamics resembles the evolution of Potts spin-glass with external global field corresponding to a panic effect in the economy. The existence of a global phase transition, between paramagnetic and ferromagnetic phases, explains the large susceptibility of the system to negative shocks. We show that bailing out the first few defaulting firms does not solve the problem, but does have the effect of alleviating considerably the global shock, as measured by the fraction of firms that are not defaulting as a consequence. This beneficial effect is the counterpart of the large vulnerability of the system of coupled firms, which are both the direct consequences of the collective self-organized endogenous behaviors of the credit ratings of the firms in our economic network.

  18. Competence and psychopathology: cascade effects in the NICHD Study of Early Child Care and Youth Development.

    PubMed

    Burt, Keith B; Roisman, Glenn I

    2010-08-01

    Existing longitudinal research on the interplay between externalizing problems, internalizing problems, and academic and social competence has documented "cascading" effects from early aggressive/disruptive behavior through impairments in competence, leading to symptoms of depression and anxiety. The primary aim of the current study was to replicate such work using the NICHD Study of Early Child Care and Youth Development while also extending the developmental window of investigation of cascades back into early childhood. Participating families (N = 1,160) completed questionnaire measures of externalizing, internalizing, and social competence (maternal report), as well as individual assessment of academic achievement, spanning five time points from age 54 months through age 15 years. A series of nested structural equation models tested predicted links across various domains of competence and psychopathology. Results were consistent with prior research, demonstrating cross-domain effects from early externalizing problems through effects on both academic and social competence into later internalizing problems. Effects held across gender and were largely unaffected by inclusion of socioeconomic status, early caregiving, and early cognitive ability as covariates in the model. PMID:20576178

  19. Resonance Effects in the NASA Transonic Flutter Cascade Facility

    NASA Technical Reports Server (NTRS)

    Lepicovsky, J.; Capece, V. R.; Ford, C. T.

    2003-01-01

    Investigations of unsteady pressure loadings on the blades of fans operating near the stall flutter boundary are carried out under simulated conditions in the NASA Transonic Flutter Cascade facility (TFC). It has been observed that for inlet Mach numbers of about 0.8, the cascade flowfield exhibits intense low-frequency pressure oscillations. The origins of these oscillations were not clear. It was speculated that this behavior was either caused by instabilities in the blade separated flow zone or that it was a tunnel resonance phenomenon. It has now been determined that the strong low-frequency oscillations, observed in the TFC facility, are not a cascade phenomenon contributing to blade flutter, but that they are solely caused by the tunnel resonance characteristics. Most likely, the self-induced oscillations originate in the system of exit duct resonators. For sure, the self-induced oscillations can be significantly suppressed for a narrow range of inlet Mach numbers by tuning one of the resonators. A considerable amount of flutter simulation data has been acquired in this facility to date, and therefore it is of interest to know how much this tunnel self-induced flow oscillation influences the experimental data at high subsonic Mach numbers since this facility is being used to simulate flutter in transonic fans. In short, can this body of experimental data still be used reliably to verify computer codes for blade flutter and blade life predictions? To answer this question a study on resonance effects in the NASA TFC facility was carried out. The results, based on spectral and ensemble averaging analysis of the cascade data, showed that the interaction between self-induced oscillations and forced blade motion oscillations is very weak and can generally be neglected. The forced motion data acquired with the mistuned tunnel, when strong self-induced oscillations were present, can be used as reliable forced pressure fluctuations provided that they are extracted

  20. Environmental endocrine disruption: an effects assessment and analysis.

    PubMed Central

    Crisp, T M; Clegg, E D; Cooper, R L; Wood, W P; Anderson, D G; Baetcke, K P; Hoffmann, J L; Morrow, M S; Rodier, D J; Schaeffer, J E; Touart, L W; Zeeman, M G; Patel, Y M

    1998-01-01

    This report is an overview of the current state of the science relative to environmental endocrine disruption in humans, laboratory testing, and wildlife species. Background information is presented on the field of endocrinology, the nature of hormones, and potential sites for endocrine disruption, with specific examples of chemicals affecting these sites. An attempt is made to present objectively the issue of endocrine disruption, consider working hypotheses, offer opposing viewpoints, analyze the available information, and provide a reasonable assessment of the problem. Emphasis is placed on disruption of central nervous system--pituitary integration of hormonal and sexual behavioral activity, female and male reproductive system development and function, and thyroid function. In addition, the potential role of environmental endocrine disruption in the induction of breast, testicular, and prostate cancers, as well as endometriosis, is evaluated. The interrelationship of the endocrine and immune system is documented. With respect to endocrine-related ecological effects, specific case examples from the peer-reviewed literature of marine invertebrates and representatives of the five classes of vertebrates are presented and discussed. The report identifies some data gaps in our understanding of the environmental endocrine disruption issue and recommends a few research needs. Finally, the report states the U.S. Environmental Protection Agency Science Policy Council's interim position on endocrine disruption and lists some of the ongoing activities to deal with this matter. PMID:9539004

  1. Disruption effects from the collision of quasi-flat beams

    SciTech Connect

    Chen, Pisin

    1993-04-01

    The disruption effects from the collision of round beams and flat beams in linear colliders have been studied in the past, and has by now been well understood. In practice, however, in the current SLC running condition and in several designs of the next generation linear colliders, the quasi-flat beam geometries are expected. Namely, the beam aspect ratio R {equivalent_to} {sigma}{sub x}/{sigma}{sub y} > 1, but not infinitely large. In this regime the disruption effects in both x and y dimensions should be carefully included in order to properly describe the beam-beam interaction phenomena. In this paper we investigate two major disruption effects for the quasi-flat beam regime: The luminosity enhancement factor and the effective beamstrahlung. Computer simulations are employed and simple scaling laws are deduced.

  2. Endocrine disrupting effects of butylated hydroxyanisole (BHA - E320)

    PubMed Central

    POP, ANCA; KISS, BELA; LOGHIN, FELICIA

    2013-01-01

    Butylated hydroxyanisole (BHA) is extensively used as antioxidant in foods, food packaging, cosmetics and pharmaceuticals. In the past years, it raised concerns regarding its possible endocrine disrupting effect. The existing in vitro studies indicate that BHA presents a weak estrogenic effect and also anti-androgenic properties while an in vivo study found it to have antiestrogenic properties. There is no sufficient data available at the moment to draw a conclusion regarding the safety of BHA when referring to its endocrine disrupting effect. Since a fraction of the population might be exposed to doses superior to the acceptable daily intake (ADI), it is important to gather more in vitro and in vivo data concerning the potential effects that BHA might have alone, but also in mixtures with natural hormones or other endocrine disrupting compounds. PMID:26527908

  3. Effect of sonication frequency on the disruption of algae.

    PubMed

    Kurokawa, Masaki; King, Patrick M; Wu, Xiaoge; Joyce, Eadaoin M; Mason, Timothy J; Yamamoto, Ken

    2016-07-01

    In this study, the efficiency of ultrasonic disruption of Chaetoceros gracilis, Chaetoceros calcitrans, and Nannochloropsis sp. was investigated by applying ultrasonic waves of 0.02, 0.4, 1.0, 2.2, 3.3, and 4.3 MHz to algal suspensions. The results showed that reduction in the number of algae was frequency dependent and that the highest efficiency was achieved at 2.2, 3.3, and 4.3MHz for C. gracilis, C. calcitrans, and Nannochloropsis sp., respectively. A review of the literature suggested that cavitation, rather than direct effects of ultrasonication, are required for ultrasonic algae disruption, and that chemical effects are likely not the main mechanism for algal cell disruption. The mechanical resonance frequencies estimated by a shell model, taking into account elastic properties, demonstrated that suitable disruption frequencies for each alga were associated with the cell's mechanical properties. Taken together, we consider here that physical effects of ultrasonication were responsible for algae disruption. PMID:26964936

  4. Effects of vimentin disruption on the mechanoresponses of articular chondrocyte.

    PubMed

    Chen, Cheng; Yin, Li; Song, Xiongbo; Yang, Hao; Ren, Xiang; Gong, Xiaoyuan; Wang, Fuyou; Yang, Liu

    2016-01-01

    Human articular cartilage is subjected to repetitive mechanical loading during life time. As the only cellular component of articular cartilage, chondrocytes play a key role in the mechanotransduction within this tissue. The mechanoresponses of chondrocytes are largely determined by the cytoskeleton. Vimentin intermediate filaments, one of the major cytoskeletal components, have been shown to regulate chondrocyte phenotype. However, the contribution of vimentin in chondrocyte mechanoresponses remains less studied. In this study, we seeded goat articular chondrocytes on a soft polyacrylamide gel, and disrupted the vimentin cytoskeleton using acrylamide. Then we applied a transient stretch or compression to the cells, and measured the changes of cellular stiffness and traction forces using Optical Magnetic Twisting Cytometry and Traction Force Microscopy, respectively. In addition, to study the effects of vimentin disruption on the intracellular force generation, we treated the cells with a variety of reagents that are known to increase or decrease cytoskeletal tension. We found that, after a compression, the contractile moment and cellular stiffness were not affected in untreated chondrocytes, but were decreased in vimentin-disrupted chondrocytes; after a stretch, vimentin-disrupted chondrocytes showed a lower level of fluidization-resolidification response compared to untreated cells. Moreover, vimentin-disrupted chondrocytes didn't show much difference to control cells in responding to reagents that target actin and ROCK pathway, but showed a weaker response to histamine and isoproterenol. These findings confirmed chondrocyte vimentin as a major contributor in withstanding compressive loading, and its minor role in regulating cytoskeletal tension. PMID:26616052

  5. Effect of the good behavior game on disruptive library behavior.

    PubMed

    Fishbein, J E; Wasik, B H

    1981-01-01

    A modification of the good behavior game was used to reduce disruptive behaviors during a weekly library period of children in a fourth-grade class. Modifications included student input in designing rules, attempts to state rules in positive terms, observation of class behavior in the experimental (library) setting as well as in a comparison (classroom) setting, and librarian involvement in instituting the game coupled with teacher involvement in delivering reinforcers. Reinforcers consisted of special classroom activities conducted by the teacher with winning team members. Modification of the good behavior game did not detract from its effectiveness in reducing disruptive and off-task behavior. PMID:16795642

  6. Intellectual Disability Modifies Gender Effects on Disruptive Behaviors

    ERIC Educational Resources Information Center

    Einfeld, Stewart L.; Gray, Kylie M.; Ellis, Louise A.; Taffe, John; Emerson, Eric; Tonge, Bruce J.; Horstead, Sian K.

    2010-01-01

    In typically developing children, boys are more commonly diagnosed than girls with disruptive behavior disorders, namely, attention-deficit/hyperactivity disorder, conduct disorder, and oppositional defiant disorder. For children with intellectual disability (ID), the evidence for this gender effect is less clear. In this report we examine gender…

  7. Disruptive Effects of Contingent Food on High-Probability Behavior

    ERIC Educational Resources Information Center

    Frank-Crawford, Michelle A.; Borrero, John C.; Nguyen, Linda; Leon-Enriquez, Yanerys; Carreau-Webster, Abbey B.; DeLeon, Iser G.

    2012-01-01

    The delivery of food contingent on 10 s of consecutive toy engagement resulted in a decrease in engagement and a corresponding increase in other responses that had been previously reinforced with food. Similar effects were not observed when tokens exchangeable for the same food were delivered, suggesting that engagement was disrupted by the…

  8. EFFECTIVE RISK MANAGEMENT OF ENDOCRINE DISRUPTING CHEMICALS WORKSHOP NEWMEDIA CD

    EPA Science Inventory

    This product is a CD-ROM version of the workshop, Effective Risk Management of Endocrine Disrupting Chemicals, held in January 2002, in Cincinnati, Ohio. The goal of this workshop was to introduce the science and engineering behind managing the potential risk of suspected endocri...

  9. Lethal control of an apex predator has unintended cascading effects on forest mammal assemblages

    PubMed Central

    Colman, N. J.; Gordon, C. E.; Crowther, M. S.; Letnic, M.

    2014-01-01

    Disruption to species-interaction networks caused by irruptions of herbivores and mesopredators following extirpation of apex predators is a global driver of ecosystem reorganization and biodiversity loss. Most studies of apex predators' ecological roles focus on effects arising from their interactions with herbivores or mesopredators in isolation, but rarely consider how the effects of herbivores and mesopredators interact. Here, we provide evidence that multiple cascade pathways induced by lethal control of an apex predator, the dingo, drive unintended shifts in forest ecosystem structure. We compared mammal assemblages and understorey structure at seven sites in southern Australia. Each site comprised an area where dingoes were poisoned and an area without control. The effects of dingo control on mammals scaled with body size. Activity of herbivorous macropods, arboreal mammals and a mesopredator, the red fox, were greater, but understorey vegetation sparser and abundances of small mammals lower, where dingoes were controlled. Structural equation modelling suggested that both predation by foxes and depletion of understorey vegetation by macropods were related to small mammal decline at poisoned sites. Our study suggests that apex predators’ suppressive effects on herbivores and mesopredators occur simultaneously and should be considered in tandem in order to appreciate the extent of apex predators’ indirect effects. PMID:24619441

  10. Lethal control of an apex predator has unintended cascading effects on forest mammal assemblages.

    PubMed

    Colman, N J; Gordon, C E; Crowther, M S; Letnic, M

    2014-05-01

    Disruption to species-interaction networks caused by irruptions of herbivores and mesopredators following extirpation of apex predators is a global driver of ecosystem reorganization and biodiversity loss. Most studies of apex predators' ecological roles focus on effects arising from their interactions with herbivores or mesopredators in isolation, but rarely consider how the effects of herbivores and mesopredators interact. Here, we provide evidence that multiple cascade pathways induced by lethal control of an apex predator, the dingo, drive unintended shifts in forest ecosystem structure. We compared mammal assemblages and understorey structure at seven sites in southern Australia. Each site comprised an area where dingoes were poisoned and an area without control. The effects of dingo control on mammals scaled with body size. Activity of herbivorous macropods, arboreal mammals and a mesopredator, the red fox, were greater, but understorey vegetation sparser and abundances of small mammals lower, where dingoes were controlled. Structural equation modelling suggested that both predation by foxes and depletion of understorey vegetation by macropods were related to small mammal decline at poisoned sites. Our study suggests that apex predators' suppressive effects on herbivores and mesopredators occur simultaneously and should be considered in tandem in order to appreciate the extent of apex predators' indirect effects. PMID:24619441

  11. Hydrogeologic effects of natural disruptive events on nuclear waste repositories

    SciTech Connect

    Davis, S.N.

    1980-06-01

    Some possible hydrogeologic effects of disruptive events that may affect repositories for nuclear wastte are described. A very large number of combinations of natural events can be imagined, but only those events which are judged to be most probable are covered. Waste-induced effects are not considered. The disruptive events discussed above are placed into four geologic settings. Although the geology is not specific to given repository sites that have been considered by other agencies, the geology has been generalized from actual field data and is, therefore, considered to be physically reasonable. The geologic settings considered are: (1) interior salt domes of the Gulf Coast, (2) bedded salt of southeastern New Mexico, (3) argillaceous rocks of southern Nevanda, and (4) granitic stocks of the Basin and Range Province. Log-normal distributions of permeabilities of rock units are given for each region. Chapters are devoted to: poresity and permeability of natural materials, regional flow patterns, disruptive events (faulting, dissolution of rock forming minerals, fracturing from various causes, rapid changes of hydraulic regimen); possible hydrologic effects of disruptive events; and hydraulic fracturing.

  12. Biallelic Variants in UBA5 Reveal that Disruption of the UFM1 Cascade Can Result in Early-Onset Encephalopathy.

    PubMed

    Colin, Estelle; Daniel, Jens; Ziegler, Alban; Wakim, Jamal; Scrivo, Aurora; Haack, Tobias B; Khiati, Salim; Denommé, Anne-Sophie; Amati-Bonneau, Patrizia; Charif, Majida; Procaccio, Vincent; Reynier, Pascal; Aleck, Kyrieckos A; Botto, Lorenzo D; Herper, Claudia Lena; Kaiser, Charlotte Sophia; Nabbout, Rima; N'Guyen, Sylvie; Mora-Lorca, José Antonio; Assmann, Birgit; Christ, Stine; Meitinger, Thomas; Strom, Tim M; Prokisch, Holger; Miranda-Vizuete, Antonio; Hoffmann, Georg F; Lenaers, Guy; Bomont, Pascale; Liebau, Eva; Bonneau, Dominique

    2016-09-01

    Via whole-exome sequencing, we identified rare autosomal-recessive variants in UBA5 in five children from four unrelated families affected with a similar pattern of severe intellectual deficiency, microcephaly, movement disorders, and/or early-onset intractable epilepsy. UBA5 encodes the E1-activating enzyme of ubiquitin-fold modifier 1 (UFM1), a recently identified ubiquitin-like protein. Biochemical studies of mutant UBA5 proteins and studies in fibroblasts from affected individuals revealed that UBA5 mutations impair the process of ufmylation, resulting in an abnormal endoplasmic reticulum structure. In Caenorhabditis elegans, knockout of uba-5 and of human orthologous genes in the UFM1 cascade alter cholinergic, but not glutamatergic, neurotransmission. In addition, uba5 silencing in zebrafish decreased motility while inducing abnormal movements suggestive of seizures. These clinical, biochemical, and experimental findings support our finding of UBA5 mutations as a pathophysiological cause for early-onset encephalopathies due to abnormal protein ufmylation. PMID:27545681

  13. Recent Advances on Endocrine Disrupting Effects of UV Filters

    PubMed Central

    Wang, Jiaying; Pan, Liumeng; Wu, Shenggan; Lu, Liping; Xu, Yiwen; Zhu, Yanye; Guo, Ming; Zhuang, Shulin

    2016-01-01

    Ultraviolet (UV) filters are used widely in cosmetics, plastics, adhesives and other industrial products to protect human skin or products against direct exposure to deleterious UV radiation. With growing usage and mis-disposition of UV filters, they currently represent a new class of contaminants of emerging concern with increasingly reported adverse effects to humans and other organisms. Exposure to UV filters induce various endocrine disrupting effects, as revealed by increasing number of toxicological studies performed in recent years. It is necessary to compile a systematic review on the current research status on endocrine disrupting effects of UV filters toward different organisms. We therefore summarized the recent advances on the evaluation of the potential endocrine disruptors and the mechanism of toxicity for many kinds of UV filters such as benzophenones, camphor derivatives and cinnamate derivatives. PMID:27527194

  14. Recent Advances on Endocrine Disrupting Effects of UV Filters.

    PubMed

    Wang, Jiaying; Pan, Liumeng; Wu, Shenggan; Lu, Liping; Xu, Yiwen; Zhu, Yanye; Guo, Ming; Zhuang, Shulin

    2016-01-01

    Ultraviolet (UV) filters are used widely in cosmetics, plastics, adhesives and other industrial products to protect human skin or products against direct exposure to deleterious UV radiation. With growing usage and mis-disposition of UV filters, they currently represent a new class of contaminants of emerging concern with increasingly reported adverse effects to humans and other organisms. Exposure to UV filters induce various endocrine disrupting effects, as revealed by increasing number of toxicological studies performed in recent years. It is necessary to compile a systematic review on the current research status on endocrine disrupting effects of UV filters toward different organisms. We therefore summarized the recent advances on the evaluation of the potential endocrine disruptors and the mechanism of toxicity for many kinds of UV filters such as benzophenones, camphor derivatives and cinnamate derivatives. PMID:27527194

  15. Effects of social disruption in elephants persist decades after culling

    PubMed Central

    2013-01-01

    Background Multi-level fission-fusion societies, characteristic of a number of large brained mammal species including some primates, cetaceans and elephants, are among the most complex and cognitively demanding animal social systems. Many free-ranging populations of these highly social mammals already face severe human disturbance, which is set to accelerate with projected anthropogenic environmental change. Despite this, our understanding of how such disruption affects core aspects of social functioning is still very limited. Results We now use novel playback experiments to assess decision-making abilities integral to operating successfully within complex societies, and provide the first systematic evidence that fundamental social skills may be significantly impaired by anthropogenic disruption. African elephants (Loxodonta africana) that had experienced separation from family members and translocation during culling operations decades previously performed poorly on systematic tests of their social knowledge, failing to distinguish between callers on the basis of social familiarity. Moreover, elephants from the disrupted population showed no evidence of discriminating between callers when age-related cues simulated individuals on an increasing scale of social dominance, in sharp contrast to the undisturbed population where this core social ability was well developed. Conclusions Key decision-making abilities that are fundamental to living in complex societies could be significantly altered in the long-term through exposure to severely disruptive events (e.g. culling and translocation). There is an assumption that wildlife responds to increasing pressure from human societies only in terms of demography, however our study demonstrates that the effects may be considerably more pervasive. These findings highlight the potential long-term negative consequences of acute social disruption in cognitively advanced species that live in close-knit kin-based societies, and

  16. Cognitive effects of endocrine-disrupting chemicals in animals.

    PubMed Central

    Schantz, S L; Widholm, J J

    2001-01-01

    A large number of chemical pollutants including phthalates, alkylphenolic compounds, polychlorinated biphenyls and polychlorinated dibenzodioxins, organochlorine pesticides, bisphenol A, and metals including lead, mercury, and cadmium have the ability to disrupt endocrine function in animals. Some of these same chemicals have been shown to alter cognitive function in animals and humans. Because hormonally mediated events play a central role in central nervous system development and function, a number of researchers have speculated that the changes in cognitive function are mediated by the endocrine-like actions of these chemicals. In this paper we review the evidence that cognitive effects of chemicals classified as environmental endocrine disruptors are mediated by changes in hormonal function. We begin by briefly reviewing the role of gonadal steroids, thyroid hormones, and glucocorticoids in brain development and brain function. We then review the endocrine changes and cognitive effects that have been reported for selected endocrine-disrupting chemicals, discuss the evidence for causal relationships between endocrine disruption and cognitive effects, and suggest directions for future research. PMID:11748026

  17. Simulating economic effects of disruptions in the telecommunications infrastructure.

    SciTech Connect

    Cox, Roger Gary; Barton, Dianne Catherine; Reinert, Rhonda K.; Eidson, Eric D.; Schoenwald, David Alan

    2004-01-01

    CommAspen is a new agent-based model for simulating the interdependent effects of market decisions and disruptions in the telecommunications infrastructure on other critical infrastructures in the U.S. economy such as banking and finance, and electric power. CommAspen extends and modifies the capabilities of Aspen-EE, an agent-based model previously developed by Sandia National Laboratories to analyze the interdependencies between the electric power system and other critical infrastructures. CommAspen has been tested on a series of scenarios in which the communications network has been disrupted, due to congestion and outages. Analysis of the scenario results indicates that communications networks simulated by the model behave as their counterparts do in the real world. Results also show that the model could be used to analyze the economic impact of communications congestion and outages.

  18. Effects of in-cascade defect clustering on near-term defect evolution

    SciTech Connect

    Heinisch, H.L.

    1997-08-01

    The effects of in-cascade defect clustering on the nature of the subsequent defect population are being studied using stochastic annealing simulations applied to cascades generated in molecular dynamics (MD) simulations. The results of the simulations illustrates the strong influence of the defect configuration existing in the primary damage state on subsequent defect evolution. The large differences in mobility and stability of vacancy and interstitial defects and the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades have been shown to be significant factors affecting the evolution of the defect distribution. In recent work, the effects of initial cluster sizes appear to be extremely important.

  19. Thyroid Hormone-disrupting Effects and the Amphibian Metamorphosis Assay

    PubMed Central

    Miyata, Kaori; Ose, Keiko

    2012-01-01

    There are continued concerns about endocrine-disrupting chemical effects, and appropriate vertebrate models for assessment of risk are a high priority. Frog tadpoles are very sensitive to environmental substances because of their habitat and the complex processes of metamorphosis regulated by the endocrine system, mainly thyroid hormones. During metamorphosis, marked alteration in hormonal factors occurs, as well as dramatic structural and functional changes in larval tissues. There are a variety of mechanisms determining thyroid hormone balance or disruption directly or indirectly. Direct-acting agents can cause changes in thyroxine synthesis and/or secretion in thyroid through effects on peroxidases, thyroidal iodide uptake, deiodinase, and proteolysis. At the same time, indirect action may result from biochemical processes such as sulfation, deiodination and glucuronidation. Because their potential to disrupt thyroid hormones has been identified as an important consideration for the regulation of chemicals, the OECD and the EPA have each established guidelines that make use of larval African clawed frogs (Xenopus laevis) and frog metamorphosis for screening and testing of potential endocrine disrupters. The guidelines are based on evaluation of alteration in the hypothalamic-pituitary-thyroid axis. One of the primary endpoints is thyroid gland histopathology. Others are mortality, developmental stage, hind limb length, snout-vent length and wet body weight. Regarding histopathological features, the guidelines include core criteria and additional qualitative parameters along with grading. Taking into account the difficulties in evaluating amphibian thyroid glands, which change continuously throughout metamorphosis, histopathological examination has been shown to be a very sensitive approach. PMID:22481853

  20. Climate Change Has Cascading Ecological Effects on Mountain Ecosystems

    NASA Astrophysics Data System (ADS)

    Fagre, D. B.

    2007-12-01

    Evidence that ecosystems of the Northern Rocky Mountains are responding to climate change abounds. Alpine glaciers, as iconic landscape features, are disappearing rapidly with some glaciers losing one half of their area in five years. A model developed in the 1990s to predict future rates of melt has proved too conservative when compared to recent measurements. The largest glaciers in Glacier National Park are almost 10 years ahead of schedule in their retreat. The cascading ecological effects of losing glaciers in high-elevation watersheds includes shifts in distribution and dominance of temperature-sensitive stream macroinvertebrates as stream volume dwindles (or disappears) in later summer months and water temperatures increase. Critical spawning areas for threatened bull trout (Salvelinus confluentus) will be lost without the consistent supply of cold water that melting snow and ice provide and raise management questions regarding the efficacy of recovery efforts. Snowpacks are documented as becoming smaller and melting earlier in the spring, facilitating the invasion of subalpine meadows by trees and reducing habitat for current alpine wildlife. Even vital ecosystem disturbances, such as periodic snow avalanches that clear mountain slope forests, have been shown by tree-ring studies to be responsive to climatic trends and are likely to become less prevalent. Monitoring of high-elevation mountain environments is difficult and has largely been opportunistic despite the fact that these areas have experienced three times the temperature increases over the past century when compared to lowland environments. A system of alpine observatories is sorely needed. Tighter integration of mountains studies, and comparisons among diverse mountain systems of the western U.S. has been initiated by the USGS-sponsored Western Mountain Initiative and the Consortium for Integrated Climate Research in Western Mountains to begin addressing this need.

  1. Comparison of sweep and dihedral effects on compressor cascade performance

    SciTech Connect

    Sasaki, T.; Breugelmans, F.

    1998-07-01

    The influence of two stacking lines, namely sweep and dihedral, has been investigated in a linear compressor cascade. Both types of blade considered are symmetric about midspan and consist of a straight central section with either swept or dihedral sections toward the endwalls. Two types of experiment have been carried out. First, a parametric study was performed by changing both the magnitude and the extent of the sweep or dihedral. In the case of swept blades, those with forward sweep (SWF), for which the stacking line is swept in the upstream direction toward the endwall, were found to have better performance than backward-swept blades. Subsequently, four sets of SWFs were compared. In the case of dihedral blades, it is well known that the dihedral is advantageous when the angle between the suction surface and the endwall is obtuse, i.e., positive dihedral. Thus, four sets of positive dihedral blades (DHP) were compared. In both SWF and DHP blades, those configurations that have better efficiency than straight blades were determined. Second, detailed three-dimensional measurements inside the blade passage were performed in the cases that showed the best performance in the parametric study. Both SWF and DHP showed significant effects on the flowfield. In the SWF case, a vortex, which has the opposite sense to the passage vortex, was observed in the forward portion inside the blade passage. This vortex supplies high-energy fluid to the endwall region and reduces the corner stall. The secondary flow is greatly reduced. In the DHP, the blade loading was reduced at the endwall and increased at the midspan. Reduction of the corner stall and the secondary flow was also observed.

  2. THE EFFECTS OF GRAIN BOUNDARIES ON RADIATION DAMAGE PRODUCTION BY DISPLACEMENT CASCADES IN α-Fe

    SciTech Connect

    Heinisch, Howard L.; Kurtz, Richard J.; Gao, Fei

    2011-04-17

    It is well known that grain boundaries in metals can be sinks for migrating defects such as mobile interstitial atoms, but less is known about the effects of grain boundaries on defect production and defect-grain boundary interactions due to displacement cascades in the vicinity of grain boundaries. Molecular dynamics simulations were performed for displacement cascades in the vicinity of both a symmetric {Sigma}3<110>{l_brace}112{r_brace} and a symmetric {Sigma}11<110>{l_brace}323{r_brace} grain boundary (GB) in {alpha}-Fe to investigate cascade-GB interactions and defect creation near GBs. Both self-interstitial atoms and vacancies are created within the {Sigma}11 GB as well as within the {Sigma}3 GB, although fewer defects are trapped in the {Sigma}3 GB than in the {Sigma}11. See Figures 1-3 and typical cascades in Figure 4. The relative numbers of surviving vacancies and interstitials per cascade residing within the GB vary as a function of the distance of the primary knock-on atom from the GB, with more interstitials than vacancies arriving at the GB from distant cascades. For both {Sigma}3 and {Sigma}11 GBs the total number of surviving defects per cascade increases somewhat with decreasing distance of the cascade from the GB, indicating that having some fraction of the defects trapped in the GB promotes the initial survival of more cascade defects overall relative to cascades in the perfect crystal. Molecular statics simulations of defect formation energies within the GBs (Figure 5) confirm that both vacancies and self-interstitials have lower defect formation energies in both the {Sigma}3 and {Sigma}11 GBs relative to their formation energies in the perfect crystal.

  3. EFFECTS OF CHARGED PARTICLES ON CASCADE IMPACTOR CALIBRATIONS

    EPA Science Inventory

    The report gives results of a determination of collection characteristics for charged and uncharged particles in cascade impactors. Impaction collection efficiency was shown to be as much as 20 percent greater for charged particles than for uncharged particles with certain substr...

  4. Effects of N-Cadherin Disruption on Spine Morphological Dynamics

    PubMed Central

    Mysore, Shreesh P.; Tai, Chin-Yin; Schuman, Erin M.

    2007-01-01

    Structural changes at synapses are thought to be a key mechanism for the encoding of memories in the brain. Recent studies have shown that changes in the dynamic behavior of dendritic spines accompany bidirectional changes in synaptic plasticity, and that the disruption of structural constraints at synapses may play a mechanistic role in spine plasticity. While the prolonged disruption of N-cadherin, a key synaptic adhesion molecule, has been shown to alter spine morphology, little is known about the short-term regulation of spine morphological dynamics by N-cadherin. With time-lapse, confocal imaging in cultured hippocampal neurons, we examined the progression of structural changes in spines following an acute treatment with AHAVD, a peptide known to interfere with the function of N-cadherin. We characterized fast and slow timescale spine dynamics (minutes and hours, respectively) in the same population of spines. We show that N-cadherin disruption leads to enhanced spine motility and reduced length, followed by spine loss. The structural effects are accompanied by a loss of functional connectivity. Further, we demonstrate that early structural changes induced by AHAVD treatment, namely enhanced motility and reduced length, are indicators for later spine fate, i.e., spines with the former changes are more likely to be subsequently lost. Our results thus reveal the short-term regulation of synaptic structure by N-cadherin and suggest that some forms of morphological dynamics may be potential readouts for subsequent, stimulus-induced rewiring in neuronal networks. PMID:18946519

  5. Aerodynamic loading distribution effects on the overall performance of ultra-high-lift LP turbine cascades

    NASA Astrophysics Data System (ADS)

    Berrino, M.; Satta, F.; Simoni, D.; Ubaldi, M.; Zunino, P.; Bertini, F.

    2014-02-01

    The present paper reports the results of an experimental investigation aimed at comparing aerodynamic performance of three low-pressure turbine cascades for several Reynolds numbers under steady and unsteady inflows. This study is focused on finding design criteria useful to reduce both profile and secondary losses in the aero-engine LP turbine for the different flight conditions. The baseline blade cascade, characterized by a standard aerodynamic loading (Zw=1.03), has been compared with two Ultra-High-Lift profiles with the same Zweifel number (Zw=1.3 for both cascades), but different velocity peak positions, leading to front and mid-loaded blade cascade configurations. The aerodynamic flow fields downstream of the cascades have been experimentally investigated for Reynolds numbers in the range 70000effects induced by the incoming wakes at the reduced frequency f +=0.62 on both profile and secondary flow losses for the three different cascade designs have been studied. Total pressure and velocity distributions have been measured by means of a miniaturized 5-hole probe in a tangential plane downstream of the cascade for both inflow conditions. The analysis of the results allows the evaluation of the aerodynamic performance of the blade cascades in terms of profile and secondary losses and the understanding of the effects of loading distribution and Zweifel number on secondary flows. When operating under unsteady inflow, contrarily to the steady case, the mid-loaded cascade has been found to be characterized by the lowest profile and secondary losses, making it the most attractive solution for the design of blades working in real conditions where unsteady inflow effects are present.

  6. Effect of Axial Velocity Density Ratio on the Performance of a Controlled Diffusion Airfoil Compressor Cascade

    NASA Astrophysics Data System (ADS)

    Senthil Kumaran, R.; Kamble, Sachin; Swamy, K. M. M.; Nagpurwala, Q. H.; Bhat, Ananthesha

    2015-12-01

    Axial Velocity Density Ratio (AVDR) is an important parameter to check the two-dimensionality of cascade flows. It can have significant influence on the cascade performance and the secondary flow structure. In the present study, the effect of AVDR has been investigated on a highly loaded Controlled Diffusion airfoil compressor cascade. Detailed 3D Computational Fluid Dynamics (CFD) studies were carried out with the cascade at five different AVDRs. Key aerodynamic performance parameters and flow structure through the cascade were analyzed in detail. CFD results of one AVDR were validated with the experimental cascade test data and were seen to be in good agreement. Loss characteristics of the cascade varied significantly with change in AVDR. Increase in AVDR postponed the point of separation on the suction surface, produced thinner boundary layers and caused substantial drop in the pressure loss coefficient. Strong end wall vortices were noticed at AVDR of 1.177. At higher AVDRs, the flow was well guided even close to the end wall and the secondary flows diminished. The loading initially improved with increase in AVDR. Beyond a certain limit, further increase in AVDR offered no improvements to the loading but rather resulted in drop in diffusion and deviation.

  7. Quantum cascade laser combs: effects of modulation and dispersion.

    PubMed

    Villares, Gustavo; Faist, Jérôme

    2015-01-26

    Frequency comb formation in quantum cascade lasers is studied theoretically using a Maxwell-Bloch formalism based on a modal decomposition, where dispersion is considered. In the mid-infrared, comb formation persists in the presence of weak cavity dispersion (500 fs2 mm-1) but disappears when much larger values are used (30'000 fs2 mm-1). Active modulation at the round-trip frequency is found to induce mode-locking in THz devices, where the upper state lifetime is in the tens of picoseconds. Our results show that mode-locking based on four-wave mixing in broadband gain, low dispersion cavities is the most promising way of achieving broadband quantum cascade laser frequency combs. PMID:25835922

  8. Multiple Endocrine Disrupting Effects in Rats Perinatally Exposed to Butylparaben.

    PubMed

    Boberg, J; Axelstad, M; Svingen, T; Mandrup, K; Christiansen, S; Vinggaard, A M; Hass, U

    2016-07-01

    Parabens comprise a group of preservatives commonly added to cosmetics, lotions, and other consumer products. Butylparaben has estrogenic and antiandrogenic properties and is known to reduce sperm counts in rats following perinatal exposure. Whether butylparaben exposure can affect other endocrine sensitive endpoints, however, remains largely unknown. In this study, time-mated Wistar rats (n = 18) were orally exposed to 0, 10, 100, or 500 mg/kg bw/d of butylparaben from gestation day 7 to pup day 22. Several endocrine-sensitive endpoints were adversely affected. In the 2 highest dose groups, the anogenital distance of newborn male and female offspring was significantly reduced, and in prepubertal females, ovary weights were reduced and mammary gland outgrowth was increased. In male offspring, sperm count was significantly reduced at all doses from 10 mg/kg bw/d. Testicular CYP19a1 (aromatase) expression was reduced in prepubertal, but not adult animals exposed to butylparaben. In adult testes, Nr5a1 expression was reduced at all doses, indicating persistent disruption of steroidogenesis. Prostate histology was altered at prepuberty and adult prostate weights were reduced in the high dose group. Thus, butylparaben exerted endocrine disrupting effects on both male and female offspring. The observed adverse developmental effect on sperm count at the lowest dose is highly relevant to risk assessment, as this is the lowest observed adverse effect level in a study on perinatal exposure to butylparaben. PMID:27122241

  9. Effect of tubing deposition, breathing pattern, and temperature on aerosol mass distribution measured by cascade impactor.

    PubMed

    Gurses, Burak K; Smaldone, Gerald C

    2003-01-01

    Aerosols produced by nebulizers are often characterized on the bench using cascade impactors. We studied the effects of connecting tubing, breathing pattern, and temperature on mass-weighted aerodynamic particle size aerosol distributions (APSD) measured by cascade impaction. Our experimental setup consisted of a piston ventilator, low-flow (1.0 L/min) cascade impactor, two commercially available nebulizers that produced large and small particles, and two "T"-shaped tubes called "Tconnector(cascade)" and "Tconnector(nebulizer)" placed above the impactor and the nebulizer, respectively. Radiolabeled normal saline was nebulized using an airtank at 50 PSIG; APSD, mass balance, and Tconnector(cascade) deposition were measured with a gamma camera and radioisotope calibrator. Flow through the circuit was defined by the air tank (standing cloud, 10 L/min) with or without a piston pump, which superimposed a sinusoidal flow on the flow from the air tank (tidal volume and frequency of breathing). Experiments were performed at room temperature and in a cooled environment. With increasing tidal volume and frequency, smaller particles entered the cascade impactor (decreasing MMAD; e.g., Misty-Neb, 4.2 +/- 0.9 microm at lowest ventilation and 2.7 +/- 0.1 microm at highest, p = 0.042). These effects were reduced in magnitude for the nebulizer that produced smaller particles (AeroTech II, MMAD 1.8 +/- 0.1 to 1.3 +/- 0.1 microm; p = 0.0044). Deposition on Tconnector(cascade) increased with ventilation but was independent of cascade impactor flow. Imaging of the Tconnector(cascade) revealed a pattern of deposition unaffected by cascade impactor flow. These measurements suggest that changes in MMAD with ventilation were not artifacts of tubing deposition in the Tconnector(cascade). At lower temperatures, APSD distributions were more polydisperse. Our data suggest that, during patient inhalation, changes in particle distribution occur that are related to conditions in the tubing and

  10. Metabolic Effects of Bariatric Surgery in Mouse Models of Circadian Disruption

    PubMed Central

    Arble, Deanna M.; Sandoval, Darleen A.; Turek, Fred W.; Woods, Stephen C.; Seeley, Randy J.

    2015-01-01

    Background/Objectives Mounting evidence supports a link between circadian disruption and metabolic disease. Humans with circadian disruption (e.g., night-shift workers) have an increased risk of obesity and cardiometabolic diseases compared to the non-disrupted population. However, it is unclear if the obesity and obesity-related disorders associated with circadian disruption respond to therapeutic treatments as well as individuals with other types of obesity. Subjects/Methods Here, we test the effectiveness of the commonly used bariatric surgical procedure, Vertical Sleeve Gastrectomy (VSG) in mouse models of genetic and environmental circadian disruption. Results VSG led to a reduction in body weight and fat mass in both ClockΔ19 mutant and constant-light mouse models (P < .05), resulting in an overall metabolic improvement independent of circadian disruption. Interestingly, the decrease in body weight occurred without altering diurnal feeding or activity patterns (P > .05). Within circadian-disrupted models, VSG also led to improved glucose tolerance and lipid handling (P < .05). Conclusions Together these data demonstrate that VSG is an effective treatment for the obesity associated with circadian disruption, and that the potent effects of bariatric surgery are orthogonal to circadian biology. However, since the effects of bariatric surgery are independent of circadian disruption, VSG cannot be considered a cure for circadian disruption. These data have important implications for circadian-disrupted obese patients. Moreover, these results reveal new information about the metabolic pathways governing the effects of bariatric surgery as well as of circadian disruption. PMID:25869599

  11. Foster Placement Disruptions Associated with Problem Behavior: Mitigating a Threshold Effect

    ERIC Educational Resources Information Center

    Fisher, Philip A.; Stoolmiller, Mike; Mannering, Anne M.; Takahashi, Aiko; Chamberlain, Patricia

    2011-01-01

    Objective: Placement disruptions have adverse effects on foster children. Identifying reliable predictors of placement disruptions might assist in the allocation of services to prevent disruptions. There were two objectives in this study: (a) to replicate a prior finding that the number of daily child problem behaviors at entry into a new foster…

  12. Binding energy effects in cascade evolution and sputtering

    SciTech Connect

    Robinson, M.T.

    1995-06-01

    The MARLOWE model was extended to include a binding energy dependent on the local crystalline order, so that atoms are bound less strongly to their lattice sites near surfaces or associated damage. Sputtering and cascade evolution were studied on the examples of self-ion irradiations of Cu and Au monocrystals. In cascades, the mean binding energy is reduced {approximately}8% in Cu with little dependence on the initial recoil energy; in Au, it is reduced {approximately}9% at 1 keV and {approximately}15% at 100 keV. In sputtering, the mean binding energy is reduced {approximately}8% in Cu and {approximately}15% in Au with little energy dependence; the yields are increased about half as much. Most sites from which sputtered atoms originate are isolated in both metals. Small clusters of such sites occur in Cu, but there are some large clusters in Au, especially in [111] targets. There are always more large clusters with damage-dependent binding than with a constant binding energy, but only a few clusters are compact enough to be regarded as pits.

  13. Multiparametric MRI biomarkers for measuring vascular disrupting effect on cancer

    PubMed Central

    Wang, Huaijun; Marchal, Guy; Ni, Yicheng

    2011-01-01

    Solid malignancies have to develop their own blood supply for their aggressive growth and metastasis; a process known as tumor angiogenesis. Angiogenesis is largely involved in tumor survival, progression and spread, which are known to be significantly attributed to treatment failures. Over the past decades, efforts have been made to understand the difference between normal and tumor vessels. It has been demonstrated that tumor vasculature is structurally immature with chaotic and leaky phenotypes, which provides opportunities for developing novel anticancer strategies. Targeting tumor vasculature is not only a unique therapeutic intervention to starve neoplastic cells, but also enhances the efficacy of conventional cancer treatments. Vascular disrupting agents (VDAs) have been developed to disrupt the already existing neovasculature in actively growing tumors, cause catastrophic vascular shutdown within short time, and induce secondary tumor necrosis. VDAs are cytostatic; they can only inhibit tumor growth, but not eradicate the tumor. This novel drug mechanism has urged us to develop multiparametric imaging biomarkers to monitor early hemodynamic alterations, cellular dysfunctions and metabolic impairments before tumor dimensional changes can be detected. In this article, we review the characteristics of tumor vessels, tubulin-destabilizing mechanisms of VDAs, and in vivo effects of the VDAs that have been mostly studied in preclinical studies and clinical trials. We also compare the different tumor models adopted in the preclinical studies on VDAs. Multiparametric imaging biomarkers, mainly diffusion-weighted imaging and dynamic contrast-enhanced imaging from magnetic resonance imaging, are evaluated for their potential as morphological and functional imaging biomarkers for monitoring therapeutic effects of VDAs. PMID:21286490

  14. Epigenomic Disruption: The Effects of Early Developmental Exposures

    PubMed Central

    Bernal, Autumn J.; Jirtle, Randy L.

    2010-01-01

    Through DNA methylation, histone modifications, and small regulatory RNAs the epigenome systematically controls gene expression during development-- both in utero and throughout life. The epigenome is also a very reactionary system; its labile nature allows it to sense and respond to environmental perturbations to ensure survival during fetal growth. This pliability can lead to aberrant epigenetic modifications that persist into later life and induce numerous disease states. Endocrine disrupting compounds (EDCs) are ubiquitous chemicals that interfere with growth and development. Several EDCs also interfere with epigenetic programming. The investigation of the epigenotoxic effects of bisphenol A (BPA), an EDC used in the production of plastics and resins, has further raised concern for the impact of EDCs on the epigenome. Using the Agouti viable yellow (Avy) mouse model, dietary BPA exposure was shown to hypomethylate both the Avy and the CabpIAP metastable epialleles. This hypomethylating effect was counteracted with dietary supplementation of methyl donors or genistein. These results are consistent with reports of BPA and other EDCs causing epigenetic effects. Epigenotoxicity could lead to numerous developmental, metabolic, and behavioral disorders in exposed populations. The heritable nature of epigenetic changes also increases the risk for transgenerational inheritance of phenotypes. Thus, epigenotoxicity must be considered when assessing these compounds for safety. PMID:20568270

  15. Improving the cost-effectiveness equation of cascade testing for familial hypercholesterolaemia

    PubMed Central

    Pears, Robert; Griffin, Michael; Futema, Marta; Humphries, Steve E.

    2015-01-01

    Purpose of review Many international recommendations for the management of familial hypercholesterolaemia propose the use of cascade testing using the family mutation to unambiguously identify affected relatives. In the current economic climate DNA information is often regarded as too expensive. Here, we review the literature and suggest strategies to improve cost-effectiveness of cascade testing. Recent findings Advances in next-generation sequencing have both speeded up the time taken for a genetic diagnosis and reduced costs. Also, it is now clear that, in the majority of patients with a clinical diagnosis of familial hypercholesterolaemia in whom no mutation can be found, the most likely cause of their elevated LDL-cholesterol (LDL-C) is because they have inherited a greater number than average of common LDL-C raising variants in many different genes. The major cost driver for cascade testing is not DNA testing but treatment over the remaining lifetime of the identified relative. With potent statins now off-patent, the overall cost has reduced considerably, and combining these three factors, a familial hypercholesterolaemia service based around DNA-cascade testing is now less than 25% of that estimated by NICE in 2008. Summary Although all patients with a clinical diagnosis of familial hypercholesterolaemia need to have their LDL-C lowered, cascade testing should be focused on those with the monogenic form and not the polygenic form. PMID:25887683

  16. Proton kinetic effects and turbulent energy cascade rate in the solar wind.

    PubMed

    Osman, K T; Matthaeus, W H; Kiyani, K H; Hnat, B; Chapman, S C

    2013-11-15

    The first observed connection between kinetic instabilities driven by proton temperature anisotropy and estimated energy cascade rates in the turbulent solar wind is reported using measurements from the Wind spacecraft at 1 AU. We find enhanced cascade rates are concentrated along the boundaries of the (β∥, T⊥/T∥) plane, which includes regions theoretically unstable to the mirror and firehose instabilities. A strong correlation is observed between the estimated cascade rate and kinetic effects such as temperature anisotropy and plasma heating, resulting in protons 5-6 times hotter and 70%-90% more anisotropic than under typical isotropic plasma conditions. These results offer new insights into kinetic processes in a turbulent regime. PMID:24289672

  17. Effects of Individual and Group Contingencies on Disruptive Playground Behavior.

    ERIC Educational Resources Information Center

    Thomas, Jerry R.; And Others

    1987-01-01

    Two treatments, an individual behavior contract and group behavior games, were studied to determine if they reduced disruptive playground behavior. The 191 subjects were second- and fifth-grade students in two public schools. Results are discussed. (Author/MT)

  18. Development of electromagnetic cascades in the atmosphere including the Landau-Pomeranchuk-Migdal effect

    NASA Technical Reports Server (NTRS)

    Streitmatter, R. E.; Stephens, S. A.

    1985-01-01

    Numerical solutions have been obtained for the one-dimensional atmospheric electromagnetic cascade diffusion equations, including the Landau-Pomeranchuk-Migdal and screening effects. Spectra produced by primary gamma rays of various energies are given at a number of deths in the atmosphere.

  19. Interactions among predators and the cascading effects of vertebrate insectivores on arthropod communities and plants.

    PubMed

    Mooney, Kailen A; Gruner, Daniel S; Barber, Nicholas A; Van Bael, Sunshine A; Philpott, Stacy M; Greenberg, Russell

    2010-04-20

    Theory on trophic interactions predicts that predators increase plant biomass by feeding on herbivores, an indirect interaction called a trophic cascade. Theory also predicts that predators feeding on predators, or intraguild predation, will weaken trophic cascades. Although past syntheses have confirmed cascading effects of terrestrial arthropod predators, we lack a comprehensive analysis for vertebrate insectivores-which by virtue of their body size and feeding habits are often top predators in these systems-and of how intraguild predation mediates trophic cascade strength. We report here on a meta-analysis of 113 experiments documenting the effects of insectivorous birds, bats, or lizards on predaceous arthropods, herbivorous arthropods, and plants. Although vertebrate insectivores fed as intraguild predators, strongly reducing predaceous arthropods (38%), they nevertheless suppressed herbivores (39%), indirectly reduced plant damage (40%), and increased plant biomass (14%). Furthermore, effects of vertebrate insectivores on predatory and herbivorous arthropods were positively correlated. Effects were strongest on arthropods and plants in communities with abundant predaceous arthropods and strong intraguild predation, but weak in communities depauperate in arthropod predators and intraguild predation. The naturally occurring ratio of arthropod predators relative to herbivores varied tremendously among the studied communities, and the skew to predators increased with site primary productivity and in trees relative to shrubs. Although intraguild predation among arthropod predators has been shown to weaken herbivore suppression, we find this paradigm does not extend to vertebrate insectivores in these communities. Instead, vertebrate intraguild preda-tion is associated with strengthened trophic cascades, and insectivores function as dominant predators in terrestrial plant-arthropod communities. PMID:20368418

  20. Effects of the density of collision cascades: Separating contributions from dynamic annealing and energy spikes

    SciTech Connect

    Titov, A I; Karaseov, P A; Azarov, A Y; Kucheyev, S O

    2008-08-13

    We present a quantitative model for the efficiency of the molecular effect in damage buildup in semiconductors. Our model takes into account only one mechanism of the cascade density dependence: nonlinear energy spikes. In our three-dimensional analysis, the volume of each individual collision cascade is divided into small cubic cells, and the number of cells that have an average density of displacements above some threshold value is calculated. We assume that such cells experience a catastrophic crystalline-to-amorphous phase transition, while defects in the cells with lower displacement densities have perfect annihilation. For the two limiting cases of heavy (500 keV/atom {sup 209}Bi) and light (40 keV/atom {sup 14}N) ion bombardment of Si, theory predictions are in good agreement with experimental data for a threshold displacement density of 4.5 at.%. For intermediate density cascades produced by small 2.1 keV/amu PF{sub n} clusters, we show that dynamic annealing processes entirely dominate cascade density effects for PF{sub 2} ions, while energy spikes begin contributing in the case of PF{sub 4} cluster bombardment.

  1. The cascade construction of artificial ponds as a tool for urban stream restoration - The use of benthic diatoms to assess the effects of restoration practices.

    PubMed

    Żelazna-Wieczorek, Joanna; Nowicka-Krawczyk, Paulina

    2015-12-15

    A series of cascade artificial ponds were constructed to improve the ecological status of the stream. To evaluate the effects of restoration practices, a bioassessment, based on phytobenthic algae - the diatoms, was made. Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) of diatom assemblages allowed for evaluating the influence of a series of cascade artificial ponds on stream integrity. To reveal which environmental factors had the greatest influence on shaping diatom assemblages, the BIO-ENV procedure was used, and in order to examine whether these factors had equal influence on diatoms along the stream, Redundancy Analysis (RDA) was used. The analysis of diatom assemblages allowed for the calculation of the diatom indices in order to assess the water quality and the ecological status of the stream. Artificial ponds constructed on the stream had significant effects on the integrity of the stream ecosystem. Diatom assemblages characteristic of stream habitats were disrupted by the species from ponds. HCA and PCA revealed that the stream was clearly divided into three sections: ponds, stream parts under the influence of ponds, and stream parts isolated from ponds. The ponds thus altered stream environmental conditions. Benthic diatom assemblages were affected by a combination of four environmental factors: the concentration of ammonium ions, dissolved oxygen, conductivity, and the amount of total suspended material in the water. These factors, together with water pH, had a diverse influence on diatom assemblages alongside the stream, which was caused by a series of cascade ponds. In theory, this restoration practice should restore the stream close to its natural state, but bioassessment of the stream ecosystem based on diatoms revealed that there was no improvement of the ecological status alongside the stream. The construction of artificial ponds disrupted stream continuity and altered the character of the stream ecosystem. PMID:26318812

  2. Experimental research of surface roughness effects on highly-loaded compressor cascade aerodynamics

    NASA Astrophysics Data System (ADS)

    Chen, Shao-wen; Xu, Hao; Wang, Song-tao; Wang, Zhong-qi

    2014-08-01

    Aircraft engines deteriorate during continuous operation under the action of external factors including fouling, corrosion, and abrasion. The increased surface roughness of compressor passage walls limits airflow and leads to flow loss. However, the partial increase of roughness may also restrain flow separation and reduce flow loss. It is necessary to explore methods that will lower compressor deterioration, thereby improving the overall performance. The experimental research on the effects of surface roughness on highly loaded compressor cascade aerodynamics has been conducted in a low-speed linear cascade wind tunnel. The different levels of roughness are arranged on the suction surface and pressure surface, respectively. Ink-trace flow visualization has been used to measure the flow field on the walls of cascades, and a five-hole probe has been traversed across one pitch at the outlet. By comparing the total pressure loss coefficient, the distributions of the secondary-flow speed vector, and flow fields of various cases, the effects of surface roughness on the aerodynamics of a highly loaded compressor cascade are analyzed and discussed. The results show that adding surface roughness on the suction surface and pressure surface make the loss decrease in most cases. Increasing the surface roughness on the suction surface causes reduced flow speed near the blade, which helps to decrease mixing loss at the cascades outlet. Meanwhile, adding surface roughness on the suction surface restrains flow separation, leading to less flow loss. Various levels of surface roughness mostly weaken the flow turning capacity to various degrees, except in specific cases.

  3. Principal Perspectives on Social Networking and the Disruptive Effects of Cyberbullying

    ERIC Educational Resources Information Center

    Welker, Heidi Stevenson

    2010-01-01

    Cyberbullying on social networking sites such as MySpace and Facebook has had negative effects on children at school. Cyberbullying disruption during the school day adds to the complexity of maintaining school operations, safety, and academic achievement. With the advancement of technology, there is a gap in the literature on the disruption in…

  4. ENVIRONMENTAL ANALYSIS OF ENDOCRINE DISRUPTING EFFECTS FROM HYDROCARBON CONTAMINANTS IN THE ECOSYSTEM

    EPA Science Inventory

    The objective of this basic research is to characterize the potential of common hydrocarbon contaminants in ecosystems to act as endocrine disrupters. Although the endocrine disrupting effects of contaminants such as dioxin and PCBs have been well characterized in both animals an...

  5. The Effectiveness of Social Stories on Decreasing Disruptive Behaviors of Children with Autism: Three Case Studies

    ERIC Educational Resources Information Center

    Ozdemir, Selda

    2008-01-01

    The purpose of this study was to determine the effectiveness of social stories on decreasing the disruptive behaviors of children with autism. Social stories were created for three participants, ages 7 and 9, to decrease three target disruptive behaviors, using a loud voice in class, chair tipping, and cutting in lunch line. Using a…

  6. Differential Effectiveness of Interdependent and Dependent Group Contingencies in Reducing Disruptive Classroom Behavior

    ERIC Educational Resources Information Center

    Hartman, Kelsey; Gresham, Frank

    2016-01-01

    Disruptive behavior in the classroom negatively affects all students' academic engagement, achievement, and behavior. Group contingencies have been proven effective in reducing disruptive behavior as part of behavior interventions in the classroom. The Good Behavior Game is a Tier 1 classwide intervention that utilizes an interdependent group…

  7. Indirect Effects of Functional Communication Training on Non-Targeted Disruptive Behavior

    ERIC Educational Resources Information Center

    Schieltz, Kelly M.; Wacker, David P.; Harding, Jay W.; Berg, Wendy K.; Lee, John F.; Padilla Dalmau, Yaniz C.; Mews, Jayme; Ibrahimovic, Muska

    2011-01-01

    The purpose of this study was to evaluate the effects of functional communication training (FCT) on the occurrence of non-targeted disruptive behavior. The 10 participants were preschool-aged children with developmental disabilities who engaged in both destructive (property destruction, aggression, self-injury) and disruptive (hand flapping,…

  8. The Effects of Sleep Disruption on the Treatment of a Feeding Disorder

    ERIC Educational Resources Information Center

    Reed, Gregory K.; Dolezal, Danielle N.; Cooper-Brown, Linda J.; Wacker, David P.

    2005-01-01

    We evaluated the effects of sleep disruption on the mealtime behavior of a young boy with developmental disabilities. Results showed that bite acceptance was less likely to persist during meals following disrupted sleep, but only when escape extinction was not implemented. Findings are discussed in terms of establishing operations and the effects…

  9. Child Disruptive Behavior and Parenting Efficacy: A Comparison of the Effects of Two Models of Insights

    ERIC Educational Resources Information Center

    O'Connor, Erin; Rodriguez, Eileen; Cappella, Elise; Morris, Jordan; McClowry, Sandee

    2012-01-01

    In this article, we investigate the effectiveness of INSIGHTS into Children's Temperament (INSIGHTS), a temperament-based preventive intervention, in reducing the disruptive behavior problems of young children from low-income, urban families. Results indicate that children enrolled in INSIGHTS evidenced a decrease in disruptive behavior problems…

  10. Separating Effects of Frequency, Quantity, Disruptive, and Problematic Substance Use.

    ERIC Educational Resources Information Center

    Stein, Judith A.; And Others

    There is widespread concern about the use and abuse of alcohol and other drugs by adolescents and young adults. It has yet to be determined whether drug use in itself is invariably associated with disruptive or problem use of drugs. Additionally, drug use may vary by frequency and quantity of ingestion which may be differentially related to…

  11. The Disruptive Effect of Self-Objectification on Performance

    ERIC Educational Resources Information Center

    Quinn, Diane M.; Kallen, Rachel W.; Twenge, Jean M.; Fredrickson, Barbara L.

    2006-01-01

    Self-objectification is the act of viewing the self, particularly the body, from a third-person perspective. Objectification theory proposes numerous negative consequences for those who self-objectify, including decreased performance through the disruption of focused attention. In the current study, we examined whether women in a state of…

  12. Can Parenting Intervention Prevent Cascading Effects From Placement Instability to Insecure Attachment to Externalizing Problems in Maltreated Toddlers?

    PubMed

    Pasalich, Dave S; Fleming, Charles B; Oxford, Monica L; Zheng, Yao; Spieker, Susan J

    2016-08-01

    Multiple placement changes disrupt continuity in caregiving and undermine well-being in children in child welfare. This study conducted secondary data analysis of a randomized controlled trial to examine whether a relationship-based intervention, Promoting First Relationships(©) (PFR), reduced risk for a maladaptive cascade from placement instability to less secure attachment to elevated externalizing problems. Participants included caregivers (birth or foster/kin) of toddlers (10-24 months) recently transitioned to their care because of child welfare placement decisions. Although main effects of PFR on security and externalizing problems were not previously observed, this study's results revealed that PFR attenuated the association between multiple placement changes (baseline) and less security (postintervention) and that the indirect effect of placement instability on greater externalizing problems (6-month follow-up) via less security was evident only in toddlers in the comparison condition. These findings shed light on how a history of multiple caregiver changes may influence toddlers' risk for poor adjustment in subsequent placements, and the promise of supporting caregivers through a parenting intervention to prevent such risk. PMID:27381935

  13. Cascading effects of ocean acidification in a rocky subtidal community.

    PubMed

    Asnaghi, Valentina; Chiantore, Mariachiara; Mangialajo, Luisa; Gazeau, Frédéric; Francour, Patrice; Alliouane, Samir; Gattuso, Jean-Pierre

    2013-01-01

    Temperate marine rocky habitats may be alternatively characterized by well vegetated macroalgal assemblages or barren grounds, as a consequence of direct and indirect human impacts (e.g. overfishing) and grazing pressure by herbivorous organisms. In future scenarios of ocean acidification, calcifying organisms are expected to be less competitive: among these two key elements of the rocky subtidal food web, coralline algae and sea urchins. In order to highlight how the effects of increased pCO2 on individual calcifying species will be exacerbated by interactions with other trophic levels, we performed an experiment simultaneously testing ocean acidification effects on primary producers (calcifying and non-calcifying algae) and their grazers (sea urchins). Artificial communities, composed by juveniles of the sea urchin Paracentrotus lividus and calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea var stricta, Dictyota dichotoma) macroalgae, were subjected to pCO2 levels of 390, 550, 750 and 1000 µatm in the laboratory. Our study highlighted a direct pCO2 effect on coralline algae and on sea urchin defense from predation (test robustness). There was no direct effect on the non-calcifying macroalgae. More interestingly, we highlighted diet-mediated effects on test robustness and on the Aristotle's lantern size. In a future scenario of ocean acidification a decrease of sea urchins' density is expected, due to lower defense from predation, as a direct consequence of pH decrease, and to a reduced availability of calcifying macroalgae, important component of urchins' diet. The effects of ocean acidification may therefore be contrasting on well vegetated macroalgal assemblages and barren grounds: in the absence of other human impacts, a decrease of biodiversity can be predicted in vegetated macroalgal assemblages, whereas a lower density of sea urchin could help the recovery of shallow subtidal rocky areas affected by overfishing from barren grounds to

  14. Cascading Effects of Ocean Acidification in a Rocky Subtidal Community

    PubMed Central

    Asnaghi, Valentina; Chiantore, Mariachiara; Mangialajo, Luisa; Gazeau, Frédéric; Francour, Patrice; Alliouane, Samir; Gattuso, Jean-Pierre

    2013-01-01

    Temperate marine rocky habitats may be alternatively characterized by well vegetated macroalgal assemblages or barren grounds, as a consequence of direct and indirect human impacts (e.g. overfishing) and grazing pressure by herbivorous organisms. In future scenarios of ocean acidification, calcifying organisms are expected to be less competitive: among these two key elements of the rocky subtidal food web, coralline algae and sea urchins. In order to highlight how the effects of increased pCO2 on individual calcifying species will be exacerbated by interactions with other trophic levels, we performed an experiment simultaneously testing ocean acidification effects on primary producers (calcifying and non-calcifying algae) and their grazers (sea urchins). Artificial communities, composed by juveniles of the sea urchin Paracentrotus lividus and calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea var stricta, Dictyota dichotoma) macroalgae, were subjected to pCO2 levels of 390, 550, 750 and 1000 µatm in the laboratory. Our study highlighted a direct pCO2 effect on coralline algae and on sea urchin defense from predation (test robustness). There was no direct effect on the non-calcifying macroalgae. More interestingly, we highlighted diet-mediated effects on test robustness and on the Aristotle's lantern size. In a future scenario of ocean acidification a decrease of sea urchins' density is expected, due to lower defense from predation, as a direct consequence of pH decrease, and to a reduced availability of calcifying macroalgae, important component of urchins' diet. The effects of ocean acidification may therefore be contrasting on well vegetated macroalgal assemblages and barren grounds: in the absence of other human impacts, a decrease of biodiversity can be predicted in vegetated macroalgal assemblages, whereas a lower density of sea urchin could help the recovery of shallow subtidal rocky areas affected by overfishing from barren grounds to

  15. Effective equations and the inverse cascade theory for Kolmogorov flows

    NASA Technical Reports Server (NTRS)

    Weinan, E.; Shu, Chi-Wang

    1993-01-01

    We study the two-dimensional Kolmogorov flows in the limit as the forcing frequency goes to infinity. Direct numerical simulation indicates that the low frequency energy spectrum evolves to a universal kappa (exp -4) decay law. We derive effective equations governing the behavior of the large scale flow quantities. We then present numerical evidence that with smooth initial data, the solution to the effective equation develops a kappa (exp -4) type singularity at a finite time. This gives a convenient explanation for the kappa (exp -4) decay law exhibited by the original Kolmogorov flows.

  16. Effective equations and the inverse cascade theory for Kolmogorov flows

    NASA Technical Reports Server (NTRS)

    Weinan, E.; Shu, Chi-Wang

    1992-01-01

    We study the two dimensional Kolmogorov flows in the limit as the forcing frequency goes to infinity. Direct numerical simulation indicates that the low frequency energy spectrum evolves to a universal kappa (exp -4) decay law. We derive effective equations governing the behavior of the large scale flow quantities. We then present numerical evidence that with smooth initial data, the solution to the effective equation develops a kappa (exp -4) type singularity at a finite time. This gives a convenient explanation for the kappa (exp -4) decay law exhibited by the original Kolmogorov flows.

  17. Modeling elephant-mediated cascading effects of water point closure.

    PubMed

    Hilbers, Jelle P; Van Langevelde, Frank; Prins, Herbert H T; Grant, C C; Peel, Mike J S; Coughenour, Michael B; De Knegt, Henrik J; Slotow, Rob; Smit, Izak P J; Kiker, Greg A; De Boer, Willem F

    2015-03-01

    Wildlife management to reduce the impact of wildlife on their habitat can be done in several ways, among which removing animals (by either culling or translocation) is most often used. There are, however, alternative ways to control wildlife densities, such as opening or closing water points. The effects of these alternatives are poorly studied. In this paper, we focus on manipulating large herbivores through the closure of water points (WPs). Removal of artificial WPs has been suggested in order to change the distribution of African elephants, which occur in high densities in national parks in Southern Africa and are thought to have a destructive effect on the vegetation. Here, we modeled the long-term effects of different scenarios of WP closure on the spatial distribution of elephants, and consequential effects on the vegetation and other herbivores in Kruger National Park, South Africa. Using a dynamic ecosystem model, SAVANNA, scenarios were evaluated that varied in availability of artificial WPs; levels of natural water; and elephant densities. Our modeling results showed that elephants can indirectly negatively affect the distributions of meso-mixed feeders, meso-browsers, and some meso-grazers under wet conditions. The closure of artificial WPs hardly had any effect during these natural wet conditions. Under dry conditions, the spatial distribution of both elephant bulls and cows changed when the availability of artificial water was severely reduced in the model. These changes in spatial distribution triggered changes in the spatial availability of woody biomass over the simulation period of 80 years, and this led to changes in the rest of the herbivore community, resulting in increased densities of all herbivores, except for giraffe and steenbok, in areas close to rivers. The spatial distributions of elephant bulls and cows showed to be less affected by the closure of WPs than most of the other herbivore species. Our study contributes to ecologically

  18. Optical waveguide biosensor based on cascaded Mach-Zehnder interferometer and ring resonator with Vernier effect

    NASA Astrophysics Data System (ADS)

    Jiang, Xianxin; Tang, Longhua; Song, Jinyan; Li, Mingyu; He, Jian-Jun

    2014-03-01

    Optical waveguide biosensors based on silicon-on-insulator (SOI) have been extensively investigated owing to its various advantages and many potential applications. In this article, we demonstrate a novel highly sensitive biosensor based on cascaded Mach-Zehnder interferometer (MZI) and ring resonator with the Vernier effect using wavelength interrogation. The experimental results show that the sensitivity reached 1,960 nm/RIU and 19,100 nm/RIU for sensors based on MZI alone and cascaded MZI-ring with Vernier effect, respectively. A biosensing application was also demonstrated by monitoring the interaction between goat and antigoat immunoglobulin G (IgG) pairs. This integrated high sensitivity biosensor has great potential for medical diagnostic applications.

  19. Electron thermal effects on electron acceleration and energy cascades in geomagnetic field line resonances

    NASA Astrophysics Data System (ADS)

    Damiano, P. A.; Johnson, J.; Wright, A. N.

    2010-12-01

    Some of the most intense electron precipitation and largest ion outflows are found in regions of intense, Alfvenic waves. Recent analysis of auroral turbulence suggests that large-scale waves couple energy to smaller scale lengths on the order of the electron inertial, ion-acoustic or ion-gyroradius. In this presentation, we examine the effects of electron temperature on the characteristics of electron acceleration and cross-scale energy coupling of wave energy using a hybrid MHD-kinetic electron simulation of Field Line Resonances in a dipolar coordinate system. The simulations describe a cascade of energy from a large-scale global driver to kinetic scales principally in the auroral acceleration region where electron inertial effects dominate and electron acceleration occurs. However, the fine scale transverse structuring of the upward current associated with this cascade appears to depend on the temperature of the ambient electron population suggesting that the ion acoustic scale length (which is dominant at higher altitudes) can influence the characteristics of the current fragmentation. Additionally, although the majority of the electron acceleration remains in the auroral acceleration region, the higher temperature cases appear to require a more extended (along the field line) source of electrons in order to carry the parallel current. We also consider the possible mechanisms by which coupling of large and small perpendicular scale lengths occurs and what effects the addition of ion gyro-radius physics may have on the characteristics of the acceleration and cascade.

  20. CHILD DISRUPTIVE BEHAVIOR AND PARENTING EFFICACY: A COMPARISON OF THE EFFECTS OF TWO MODELS OF INSIGHTS

    PubMed Central

    O’Connor, Erin; Rodriguez, Eileen; Cappella, Elise; Morris, Jordan; McClowry, Sandee

    2012-01-01

    In this article, we investigate the effectiveness of INSIGHTS into Children’s Temperament (INSIGHTS), a temperament-based preventive intervention, in reducing the disruptive behavior problems of young children from low-income, urban families. Results indicate that children enrolled in INSIGHTS evidenced a decrease in disruptive behavior problems over the course of the intervention, with children with high maintenance temperaments evidencing the most rapid rates of decline. In addition, children in a collaborative version of the program with joint parent and teacher sessions demonstrated more rapid decreases in disruptive behavior than children in a parallel version with separate parent and teacher sessions. Furthermore, high maintenance children in the collaborative intervention evidenced lower levels of disruptive behaviors at the end of the intervention than their peers in the parallel version. Increases in parenting efficacy appeared to be the mechanism through which INSIGHTS reduced child disruptive behavior. PMID:22822277

  1. Temperature Effects on He bubbles production due to cascades in alpha-iron

    SciTech Connect

    Yang, Li; Zu, Xiaotao; Xiao, H Y.; Gao, Fei; Liu, K Z.; Heinisch, Howard L.; Kurtz, Richard J.; Yang, S Z.

    2006-07-15

    The effects of irradiation temperature on the formation of He?vacancy clusters by displacement cascades in *-Fe are investigated by molecular dynamics (MD) methods. The irradiation temperatures of 100 and 600K are considered for primary knock-on atom (PKA) energy, Ep, from 500 eV to 20 keV. The concentration of He in Fe varies from 1 to 5 at.%. We find that the number of Frenkel pairs (NF) at 600K is slightly lower than that at 100K for the same He concentration and Ep, but the number of He?vacancy clusters increases with increasing temperature for the same He concentration and energy recoils. However, the mean size of He?vacancy clusters is independent on temperature. The mechanisms of He bubble nucleation in displacement cascades at different temperatures are discussed in detail.

  2. Effect of wind tunnel acoustic modes on linear oscillating cascade aerodynamics

    NASA Technical Reports Server (NTRS)

    Buffum, Daniel H.; Fleeter, Sanford

    1993-01-01

    The aerodynamics of a biconvex airfoil cascade oscillating in torsion is investigated using the unsteady aerodynamic influence coefficient technique. For subsonic flow and reduced frequencies as large as 0.9, airfoil surface unsteady pressures resulting from oscillation of one of the airfoils are measured using flush-mounted high-frequency-response pressure transducers. The influence coefficient data are examined in detail and then used to predict the unsteady aerodynamics of a cascade oscillating at various interblade phase angles. These results are correlated with experimental data obtained in the traveling-wave mode of oscillation and linearized analysis predictions. It is found that the unsteady pressure disturbances created by an oscillating airfoil excite wind tunnel acoustic modes which have detrimental effects on the experimental data. Acoustic treatment is proposed to rectify this problem.

  3. Effect of wind tunnel acoustic modes on linear oscillating cascade aerodynamics

    NASA Technical Reports Server (NTRS)

    Buffum, D. H.; Fleeter, S.

    1994-01-01

    The aerodynamics of a biconvex airfoil cascade oscillating in torsion is investigated using the unsteady aerodynamic influence coefficient technique. For subsonic flow and reduced frequencies as large as 0.9, airfoil surface unsteady pressures resulting from oscillation of one of the airfoils are measured using flush-mounted high-frequency-response pressure transducers. The influence coefficient data are examined in detail and then used to predict the unsteady aerodynamics of a cascade oscillating at various interblade phase angles. These results are correlated with experimental data obtained in the traveling-wave mode of oscillation and linearized analysis predictions. It is found that the unsteady pressure disturbances created by an oscillating airfoil excite wind tunnel acoustic modes, which have detrimental effects on the experimental results. Acoustic treatment is proposed to rectify this problem.

  4. Cascading effects of a highly specialized beech-aphid–fungus interaction on forest regeneration

    PubMed Central

    Maynard, Lauren; Lemoine, Nathan P.; Shue, Jessica; Parker, John D.

    2014-01-01

    Specialist herbivores are thought to often enhance or maintain plant diversity within ecosystems, because they prevent their host species from becoming competitively dominant. In contrast, specialist herbivores are not generally expected to have negative impacts on non-hosts. However, we describe a cascade of indirect interactions whereby a specialist sooty mold (Scorias spongiosa) colonizes the honeydew from a specialist beech aphid (Grylloprociphilus imbricator), ultimately decreasing the survival of seedlings beneath American beech trees (Fagus grandifolia). A common garden experiment indicated that this mortality resulted from moldy honeydew impairing leaf function rather than from chemical or microbial changes to the soil. In addition, aphids consistently and repeatedly colonized the same large beech trees, suggesting that seedling-depauperate islands may form beneath these trees. Thus this highly specialized three-way beech-aphid–fungus interaction has the potential to negatively impact local forest regeneration via a cascade of indirect effects. PMID:25024911

  5. Developmental Cascade Effects of the New Beginnings Program on Adolescent Adaptation Outcomes

    PubMed Central

    Bonds, Darya D.; Wolchik, Sharlene A.; Winslow, Emily; Tein, Jenn-Yun; Sandler, Irwin N.; Millsap, Roger E.

    2010-01-01

    Using data from a 6-year longitudinal follow-up sample of 240 youth who participated in a randomized experimental trial of a preventive intervention for divorced families with children ages 9–12, the current study tested alternative cascading pathways by which the intervention decreased symptoms of internalizing disorders, symptoms of externalizing disorders, substance use, and risky sexual behavior, and increased self-esteem and academic performance in mid-to late-adolescence (15–19 years old). It was hypothesized that the impact of the program on adolescent adaptation outcomes would be explained by progressive associations between program-induced changes in parenting and youth adaptation outcomes. The results supported a cascading model of program effects in which the program was related to increased mother-child relationship quality, which was related to subsequent decreases in child internalizing problems, which then was related to subsequent increases in self-esteem and decreases in symptoms of internalizing disorders in adolescence. The results also were consistent with a model in which the program was related to increased maternal effective discipline, which was related to subsequent decreases in child externalizing problems, which then was related to subsequent decreases in symptoms of externalizing disorders, less substance use and better academic performance in adolescence. There were no significant differences in the model based on level of baseline risk or adolescent gender. These results provide support for a cascading pathways model of child and adolescent development. PMID:20883581

  6. Cascading effects of the loss of apex predatory sharks from a coastal ocean.

    PubMed

    Myers, Ransom A; Baum, Julia K; Shepherd, Travis D; Powers, Sean P; Peterson, Charles H

    2007-03-30

    Impacts of chronic overfishing are evident in population depletions worldwide, yet indirect ecosystem effects induced by predator removal from oceanic food webs remain unpredictable. As abundances of all 11 great sharks that consume other elasmobranchs (rays, skates, and small sharks) fell over the past 35 years, 12 of 14 of these prey species increased in coastal northwest Atlantic ecosystems. Effects of this community restructuring have cascaded downward from the cownose ray, whose enhanced predation on its bay scallop prey was sufficient to terminate a century-long scallop fishery. Analogous top-down effects may be a predictable consequence of eliminating entire functional groups of predators. PMID:17395829

  7. Numerical Study of the Effect of Secondary Vortex on Three-Dimensional Corner Separation in a Compressor Cascade

    NASA Astrophysics Data System (ADS)

    Liu, Yangwei; Yan, Hao; Lu, Lipeng

    2016-04-01

    The complex flow structures in a linear compressor cascade have been investigated under different incidences using both the Reynolds-averaged Navier-Stokes (RANS) and delayed detached eddy simulation (DDES) methods. The current study analyzes the development of horseshoe vortex and passage vortex in a compressor cascade based on DDES results and explores the effect of the passage vortex on corner separation using the RANS method. Results show that the effect of horseshoe vortex on three-dimensional corner separation is weak, whereas the effect of passage vortex is dominant. A large vortex breaks into many small vortices in the corner separation region, thereby resulting in strong turbulence fluctuation. The passage vortex transports the low-energetic flow near the endwall to the blade suction surface and enlarges corner separation in the cascade. Hence, total pressure loss increases in the cascade.

  8. Cascading effects of deforestation and drying trends on reduced forest resilience in the Amazon region

    NASA Astrophysics Data System (ADS)

    Zemp, Delphine; Schleussner, Carl-Friedrich; Barbosa, Henrique; Sampaio, Gilvan; Hirota, Marina; Rammig, Anja

    2015-04-01

    Increasing dryness in the Amazon region combined with forest degradation could potentially lead to critical transitions of parts of the tropical evergreen forest into seasonal forest or savanna with substantial consequences for regional as well as continental climate. In the assessment of these risks and processes involved, vegetation-climate feedbacks play a central role. In particular, the degradation of tropical forest affects cascading moisture recycling that accounts for about 10% of total South American annual precipitation. Unlike tropical dense forest with deep-rooted trees, a degraded forest experiences water deficit and decreases evapotranspiration rate during the dry season. As a result, the moisture recycling weakens, intensifying the dry season locally and downwind. This in turn affects the resilience of the remaining forested areas, which gives rise to a self-amplifying feedback - loop of forest degradation and reduced dry season precipitation. Here, we examine how perturbations of the hydrological cycle (induced by deforestation or reduced incoming moisture from the ocean) lead to cascading effects of increased dryness and reduced forest resilience. We combine a simple empirical model based on remote sensing data together with an Eulerian moisture tracking model to quantify the probability of cascading vegetation change in present day and future Amazonian rainforest.

  9. Effects of link-orientation methods on robustness against cascading failures in complex networks

    NASA Astrophysics Data System (ADS)

    Jiang, Zhong-Yuan; Ma, Jian-Feng; Shen, Yu-Long; Zeng, Yong

    2016-09-01

    Unidirectional and bidirectional links may coexist in many realistic networked complex systems such as the city transportation networks. Even more, for some considerations, several bidirectional links are shifted to unidirectional ones. Many link-orientation strategies might be employed, including High-to-Low, Low-to-High and Random direction-determining methods, abbreviated as HTLDD, LTHDD and RDD respectively. Traffic passing through a unidirectional link is restricted to one-side direction. In real complex systems, nodes are correlated with each other. The failure from an initial node may be propagated iteratively, resulting in a large scale of failures of other nodes, called cascade phenomenon which may damage the safety or security of the networked system. Assuming that traffic load on any failed node can be redistributed to its non-failed neighbors, in this work, we try to reveal the effects of unidirectional links on network robustness against cascades. Extensive simulations have been implemented on kinds of networks including Scale-Free networks, Small-World networks, and Erdös-Rényi random networks. The results showed that all of the above three direction-determining methods decrease the robustness of the original networks against cascading failure. This work can help network designers and managers understand the robustness of network well and efficiently prevent the safety events.

  10. Postural Control During Cascade Ball Juggling: Effects of Expertise and Base of Support.

    PubMed

    Rodrigues, Sérgio T; Polastri, Paula F; Gotardi, Gisele C; Aguiar, Stefane A; Mesaros, Marcelo R; Pestana, Mayara B; Barbieri, Fabio A

    2016-08-01

    Cascade ball juggling is a complex perceptual motor skill which requires efficient postural stabilization. The aim of this study was to investigate effects of experience (expert and intermediate groups) and foot distance (wide and narrow stances) on body sway of jugglers during three ball cascade juggling. A total of 10 expert jugglers and 11 intermediate jugglers participated in this study. Participants stood barefoot on the force plate (some participants wore a gaze tracking system), with feet maintained in wide and narrow conditions and performed three 40-seconds trials of the three-ball juggling task. Dependent variables were sway mean velocity, amplitude, mean frequency, number of ball cycles, fixation number, mean duration and its variability, and area of gaze displacement. Two-way analyses of variance with factors for group and condition were conducted. Experts' body sway was characterized by lower velocity and smaller amplitude as compared to intermediate group. Interestingly, the more challenging (narrow) basis of support caused significant attenuation in body sway only for the intermediate group. These data suggest that expertise in cascade juggling was associated with refined postural control. PMID:27502243

  11. Two-stage effects of awareness cascade on epidemic spreading in multiplex networks

    NASA Astrophysics Data System (ADS)

    Guo, Quantong; Jiang, Xin; Lei, Yanjun; Li, Meng; Ma, Yifang; Zheng, Zhiming

    2015-01-01

    Human awareness plays an important role in the spread of infectious diseases and the control of propagation patterns. The dynamic process with human awareness is called awareness cascade, during which individuals exhibit herd-like behavior because they are making decisions based on the actions of other individuals [Borge-Holthoefer et al., J. Complex Networks 1, 3 (2013), 10.1093/comnet/cnt006]. In this paper, to investigate the epidemic spreading with awareness cascade, we propose a local awareness controlled contagion spreading model on multiplex networks. By theoretical analysis using a microscopic Markov chain approach and numerical simulations, we find the emergence of an abrupt transition of epidemic threshold βc with the local awareness ratio α approximating 0.5 , which induces two-stage effects on epidemic threshold and the final epidemic size. These findings indicate that the increase of α can accelerate the outbreak of epidemics. Furthermore, a simple 1D lattice model is investigated to illustrate the two-stage-like sharp transition at αc≈0.5 . The results can give us a better understanding of why some epidemics cannot break out in reality and also provide a potential access to suppressing and controlling the awareness cascading systems.

  12. Cascading effects of fire exclusion in Rocky Mountain ecosystems: a literature review

    USGS Publications Warehouse

    Keane, R.E.; Ryan, K.C.; Veblen, T.T.; Allen, C.D.; Logan, J.; Hawkes, B.

    2002-01-01

    The health of many Rocky Mountain ecosystems is in decline because of the policy of excluding fire in the management of these ecosystems. Fire exclusion has actually made it more difficult to fight fires, and this poses greater risks to the people who fight fires and for those who live in and around Rocky Mountain forests and rangelands. This paper discusses the extent of fire exclusion in the Rocky Mountains, then details the diverse and cascading effects of suppressing fires in the Rocky Mountain landscape by spatial scale, ecosystem characteristic, and vegetation type. Also discussed are the varied effects of fire exclusion on some important, keystone ecosystems and human concerns.

  13. The effect of displacement cascades on small helium bubbles in aluminum and gold

    SciTech Connect

    Donnelly, S.E.; Valizadeh, R.; Vishnyakov, V.; Birtcher, R.C.; Templier, C.

    1994-12-01

    The evolution of individual helium bubbles in thin foils of gold and aluminum irradiated with 400 keV Ar+ and 200 keV Xe+ has been followed with in-situ transmission electron microscopy for a comparison between the effects of dilute (Al) and dense (Au) collision cascades. Bubble shrinkage in Al has been attributed to direct displacement of the gas out of the bubbles. Effects in Au, include the disappearance and Brownian motion of bubbles under irradiation, and are consistent with thermal spike processes seen in molecular dynamics simulations.

  14. Preliminary Failure Modes and Effects Analysis of the US Massive Gas Injection Disruption Mitigation System Design

    SciTech Connect

    Lee C. Cadwallader

    2013-10-01

    This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a candidate design for the ITER Disruption Mitigation System. This candidate is the Massive Gas Injection System that provides machine protection in a plasma disruption event. The FMEA was quantified with “generic” component failure rate data as well as some data calculated from operating facilities, and the failure events were ranked for their criticality to system operation.

  15. Discharge simulation using downscaled spatial rainfall field by introducing correlation effect in random cascade method

    NASA Astrophysics Data System (ADS)

    Shrestha, R. K.; Tachikawa, Y.; Takara, K.

    2003-04-01

    The simulation of spatial rainfall field based on non-homogenous random cascade method disaggregates a regionally averaged rainfall such as the GCM output. The cascade-generators are used to disaggregate and produce spatial patterns across the region (Over and Gupta, 1996; Chatchai et al. 2000; Tachikawa et al. 2003). However, the disaggregated data is rarely used to produce discharge by using distributed hydrological model. The hesitation to use disaggregated GCM data in discharge simulation is mainly due to lower reliability to reproduce spatial pattern and higher chance of magnitude fluctuation in a few trials of disaggregation. Long term disaggregation results, which are expected to produce true spatial pattern, may not be convenient for practical discharge simulation. A modified method is tested by keeping the volume balanced and forcing the location of cascade generators on the basis of spatial correlation of rainfall field with respect to surround regions. In this method, a reference matrix is prepared, which is calculated for every target grid by summing the multiplication of rainfall magnitude and spatial correlation coefficient of the respective reference grids. The reference matrix is used to adjust the location of random generator in two ways -- hierarchically and statistically. So, this method is designated as Hierarchical and Statistical Adjustment (HSA) method. The HSA method preserves the magnitude of random cascade generators but modifies the location. Unlike the previous non-homogenous random cascade method, this method produced similar spatial patterns as that of ground truth in every realization, which is a clear indication of improved reliability of the disaggregation method from coarse GCM output to a finer resolution as demanded by the hydrological model. The forced volume balance may be justified from the engineering aspect to maintain the same input quantity of rainfall in a watershed for hydrologic simulation purpose. The downscaled data

  16. Trophic cascade effects of avian predation on a willow in an urban wetland.

    PubMed

    Wu, Pei-Chen; Shaner, Pei-Jen L

    2016-01-01

    Trophic cascades play a crucial role in ecosystem functioning. In this study, we tested the effects of avian predation on willows (Salix warburgii) and associated arthropods in an urban wetland. We excluded birds by netting around willow branches for 20 months from September-November 2010 to June 2012. We compared the leaf count, leaf area, leaf biomass, bud count, catkin (flower) count and herbivory from pairs of bird-exclusion and no-exclusion branches on 11 trees. Simultaneously, we compared herbivorous and predatory arthropod abundances associated with bird-exclusion and no-exclusion branches. Another nine trees were used as reference branches to assess whether the bird exclusion impacted other branches of the same trees (i.e., no-exclusion branches). Bird exclusion resulted in increased herbivory 1 year after the treatment, followed by a reduced leaf count, leaf area, leaf biomass, bud count and catkin count in the second year. The bird-exclusion branches exhibited greater spider abundance than the no-exclusion branches. However, herbivorous arthropod abundances were similar between the branch types. The reference branches had similar values in all plant traits and for all arthropod abundances to those of the no-exclusion branches. This study demonstrated the branch-level effects of trophic cascades on willows via the exclusion of birds and a resulting reduction in herbivory. However, whether and how the arthropods mediate such effects require further investigation. This study adds to the limited empirical data demonstrating the effects of trophic cascades on plant reproduction. Our findings highlight the importance of bird conservation in urban wetlands. PMID:26391382

  17. Heat transfer and film cooling effectiveness in a linear airfoil cascade

    SciTech Connect

    Abuaf, N.; Bunker, R.; Lee, C.P.

    1997-04-01

    A warm (315 C) wind tunnel test facility equipped with a linear cascade of film cooled vane airfoils was used in the simultaneous determination of the local gas side heat transfer coefficients and the adiabatic film cooling effectiveness. The test rig can be operated in either a steady-state or a transient mode. The steady-state operation provides adiabatic film cooling effectiveness values while the transient mode generates data for the determination of the local heat transfer coefficients from the temperature-time variations and of the film effectiveness from the steady wall temperatures within the same aerothermal environment. The linear cascade consists of five airfoils. The 14% cascade inlet free-stream turbulence intensity is generated by a perforated plate, positioned upstream of the airfoil leading edge. For the first transient tests, five cylinders having roughly the same blockage as the initial 20% axial chord of the airfoils were used. The cylinder stagnation point heat transfer coefficients compare well with values calculated from correlations. Static pressure distributions measured over an instrumented airfoil agree with inviscid predictions. Heat transfer coefficients and adiabatic film cooling effectiveness results were obtained with a smooth airfoil having three separate film injection locations, two along the suction side, and the third one covering the leading edge showerhead region. Near the film injection locations, the heat transfer coefficients increase with the blowing film. At the termination of the film cooled airfoil tests, the film holes were plugged and heat transfer tests were conducted with non-film cooled airfoils. These results agree with boundary layer code predictions.

  18. An investigation of the effect of cascade area ratios on transonic compressor performance

    SciTech Connect

    Wadia, A.R.; Copenhaver, W.W.

    1996-10-01

    Transonic compressor rotor performance is highly sensitive to variations in cascade area ratios. This paper reports on the design, experimental evaluation, and three-dimensional viscous analysis of four low-aspect-ratio transonic rotors that demonstrate the effects of cascade throat area, internal contraction, and trailing edge effective camber on compressor performance. The cascade throat area study revealed that tight throat margins result in increased high-speed efficiency with lower part-speed performance. Stall line was also improved slightly over a wide range of speeds with a lower throat-to-upstream capture area ratio. Higher internal contraction, expressed as throat-to-mouth area ratio, also results in increased design point peak efficiency, but again costs performance at the lower speeds. Reducing the trailing edge effective camber, expressed as throat-to-exit area ratio, results in an improvement in peak efficiency level without significantly lowering the stall line. Among all four rotors, the best high-speed efficiency was obtained by the rotor with a tight throat margin and highest internal contraction, but its efficiency was the lowest at part speed. The best compromise between high-speed and part-speed efficiency was achieved by the rotor with a large throat and a lower trailing edge effective camber. The difference in the shock structure and the shock boundary layer interaction of the four blades was analyzed using a three-dimensional viscous code. The analytical results are used to supplement the data and provide further insight into the detailed physics of the flow field.

  19. 3D Effects in the Formation of Zonal Jets Through Inverse Cascade

    NASA Astrophysics Data System (ADS)

    Sayanagi, Kunio M.; Showman, A. P.

    2006-09-01

    The atmospheric zonal jets on Jupiter and Saturn are characterized by the broad, prograde, equatorial jet and the narrower, higher-latitude jets that alternate between prograde and retrograde. The question of what controls the widths and directions of those jets remains a major unsolved problem in geophysical fluid dynamics. Past studies have shown that, in shallow flows on a rotating sphere, small random vortices can undergo inverse cascade to form zonal jets with a characteristic width called the Rhines scale. Most of the studies to date use 2D non-divergent or shallow-water models in studying this zonal jet formation mechanism. However, in the parameter ranges representative of the Jovian conditions, the flows produced by 2D non-divergent models are typically dominated by strong circumpolar jets, and the shallow-water models produce a robust retrograde equatorial jet. These models' apparent inabilities in reproducing some key Jovian jet features may suggest the importance of 3D effects in controlling the jets' large-scale horizontal structures. To date, Kitamura and Matsuda (Fluid Dynamics Research, 34, 33-57, 2004) is the only published study that analyzes the 3D effects in the zonalization of fine-scale random turbulence through the inverse cascade. Their two-layer primitive equation simulations of free-evolving flows resulted in circumpolar jet dominated flows, although slower mid-latitude jets are also present. Our study is a significant extension over that by Kitamura and Matsuda and includes substantially more layers to study the zonalization process to more fully resolve relevant 3D effects in the inverse cascade. We test the flow behavior's dependence on the deformation radius and the resulting vertical structures in both spherical and beta-plane geometries. Our study uses the Explicit Planetary Isentropic Coordinate (EPIC) model (Dowling et al, Icarus, 32, 221-238., 1998). The research is supported by a NASA Planetary Atmospheres grant to APS.

  20. 3D Effects in the Formation of Zonal Jets Through Inverse Cascade

    NASA Astrophysics Data System (ADS)

    Sayanagi, K. M.; Showman, A. P.

    2006-12-01

    The atmospheric zonal jets on Jupiter and Saturn are characterized by the broad, prograde, equatorial jet and the narrower, higher-latitude jets that alternate between prograde and retrograde. The question of what controls the widths and directions of those jets remains a major unsolved problem in geophysical fluid dynamics. Past studies have shown that, in shallow flows on a rotating sphere, small random vortices can undergo inverse cascade to form zonal jets with a characteristic width called the Rhines scale. Most of the studies to date use 2D non-divergent or shallow-water models in studying this zonal jet formation mechanism. However, in the parameter ranges representative of the Jovian conditions, the flows produced by 2D non- divergent models are typically dominated by strong circumpolar jets, and the shallow-water models produce a robust retrograde equatorial jet. These models' apparent inabilities in reproducing some key Jovian jet features may suggest the importance of 3D effects in controlling the jets' large-scale horizontal structures. To date, Kitamura and Matsuda (Fluid Dynamics Research, 34, 33-57, 2004) is the only published study that analyzes the 3D effects in the zonalization of fine-scale random turbulence through the inverse cascade. Their two-layer primitive equation simulations of free-evolving flows resulted in circumpolar jet dominated flows, although slower mid-latitude jets are also present. Our study is a significant extension over that by Kitamura and Matsuda and includes substantially more layers to study the zonalization process to more fully resolve relevant 3D effects in the inverse cascade. We test the flow behavior's dependence on the deformation radius and the resulting vertical structures in both spherical and beta-plane geometries. Our study uses the Explicit Planetary Isentropic Coordinate (EPIC) model (Dowling et al, Icarus, 32, 221-238., 1998). The research is supported by a NASA Planetary Atmospheres grant to APS.

  1. Effects of indirect bandgap top cells in a monolithic cascade cell structure

    NASA Technical Reports Server (NTRS)

    Curtis, H. B.; Godlewski, M. P.

    1982-01-01

    The effect of having a slightly indirect top cell in a three junction cascade monolithic stack is calculated. The minority carrier continuity equations are utilized to calculate individual junction performance. Absorption coefficient curves for general III-V compounds are calculated for a variety of direct and indirect gap materials. The results indicate that for a small excursion into the indirect region, (about 0.1 eV), the loss of efficiency is acceptably small (less than 2.5 percent) and considerably less than attempting to make the top junction a smaller direct bandgap.

  2. Indirect Effects of Functional Communication Training on Non-Targeted Disruptive Behavior

    PubMed Central

    Schieltz, Kelly M.; Wacker, David P.; Harding, Jay W.; Berg, Wendy K.; Lee, John F.; Dalmau, Yaniz C. Padilla; Mews, Jayme; Ibrahimović, Muška

    2013-01-01

    The purpose of this study was to evaluate the effects of functional communication training (FCT) on the occurrence of non-targeted disruptive behavior. The 10 participants were preschool-aged children with developmental disabilities who engaged in both destructive (property destruction, aggression, self-injury) and disruptive (hand flapping, spinning in circles, shrill laughter, screaming, crying) behaviors. Only destructive behavior was targeted for the functional analyses and FCT, but data were also collected on disruptive behaviors. All procedures were conducted in the participants’ homes by their mothers with investigator coaching. Phase 1 consisted of conducting a functional analysis within a multielement design. Phase 2 consisted of conducting FCT with demand fading and repeated extinction baselines within a reversal design. Single-case data are provided for 3 participants, and summary data are provided for all 10 participants. Results of phase 1 showed that all participants’ destructive and disruptive behavior was maintained, at least in part, by negative reinforcement. Results of phase 2 showed that both destructive behavior and non-targeted disruptive behavior occurred at lower levels during FCT when compared to the functional analysis demand condition and baseline conditions, suggesting that FCT was effective in decreasing both target destructive behavior and non-targeted disruptive behaviors. PMID:23487563

  3. Parametric analysis of the thermal effects on the divertor in tokamaks during plasma disruptions

    SciTech Connect

    Bruhn, M.L.

    1988-04-01

    Plasma disruptions are an ever present danger to the plasma-facing components in today's tokamak fusion reactors. This threat results from our lack of understanding and limited ability to control this complex phenomenon. In particular, severe energy deposition occurs on the divertor component of the double-null configured tokamak reactor during such disruptions. A hybrid computational model developed to estimate and graphically illustrate global thermal effects of disruptions on the divertor plates is described in detail. The quasi-two-dimensional computer code, TADDPAK (Thermal Analysis Divertor during Disruptions PAcKage), is used to conduct parametric analysis for the TIBER II Tokamak Engineering Test Reactor Design. The dependence of these thermal effects on divertor material choice, disruption pulse length, disruption pulse shape, and the characteristic thickness of the plasma scrape-off layer is investigated for this reactor design. Results and conclusions from this analysis are presented. Improvements to this model and issues that require further investigation are discussed. Cursory analysis for ITER (International Thermonuclear Experimental Reactor) is also presented in the appendix. 75 refs., 49 figs., 10 tabs.

  4. Seasonal Trophic Niche Shift and Cascading Effect of a Generalist Predator Fish

    PubMed Central

    Gong, Zhijun; Zhang, Min; Xie, Ping; Hansson, Lars-Anders

    2012-01-01

    Few studies have examined how foraging niche shift of a predator over time cascade down to local prey communities. Here we examine patterns of temporal foraging niche shifts of a generalist predator (yellow catfish, Pelteobagrus fulvidraco) and the abundance of prey communities in a subtropical lake. We predicted that the nature of these interactions would have implications for patterns in diet shifts and growth of the predator. Our results show significant decreases in planktivory and benthivory from late spring to summer and autumn, whereas piscivory increased significantly from mid-summer until late autumn and also increased steadily with predator body length. The temporal dynamics in predator/prey ratios indicate that the predation pressure on zooplankton and zoobenthos decreased when the predation pressure on the prey fish and shrimps was high. Yellow catfish adjusted their foraging strategies to temporal changes in food availability, which is in agreement with optimal foraging theory. Meanwhile the decrease in planktivory and benthivory of yellow catfish enabled primary consumers, such as zooplankton and benthic invertebrates, to develop under low grazing pressure via trophic cascading effects in the local food web. Thus, yellow catfish shifts its foraging niche to intermediate consumers in the food web to benefit the energetic demand on growth and reproduction during summer, which in turn indirectly facilitate the primary consumers. In complex food webs, trophic interactions are usually expected to reduce the strength and penetrance of trophic cascades. However, our study demonstrates strong associations between foraging niche of piscivorous fish and abundance of prey. This relationship appeared to be an important factor in producing top-down effects on both benthic and planktonic food webs. PMID:23251347

  5. RISKS OF ENDOCRINE DISRUPTING COMPOUNDS TO WILDLIFE: EXTRAPOLATING FROM EFFECTS ON INDIVIDUALS TO POPULATION RESPONSE

    EPA Science Inventory

    Much of the research conducted on the effects of endocrine disrupting compounds (EDCs) has been focused on effects at the individual or subindividual level. The challenge from the point of view of ecological risk assessment is to determine effects on populations and higher levels...

  6. RISKS OF ENDROCRINE DISRUPTING COMPOUNDS TO WILDLIFE EXTRAPOLATED FROM EFFECTS ON INDIVIDUALS TO POPULATION RESPONSE

    EPA Science Inventory

    Much of the research conducted on the effects of endocrine disrupting compounds (EDCs) has been focused on effects at the individual or sub-individual level. The challenge from the point of view of ecological risk assessment is to determine effects on populations and higher level...

  7. The signatures of Anthropocene defaunation: cascading effects of the seed dispersal collapse

    PubMed Central

    Pérez-Méndez, Néstor; Jordano, Pedro; García, Cristina; Valido, Alfredo

    2016-01-01

    Anthropogenic activity is driving population declines and extinctions of large-bodied, fruit-eating animals worldwide. Loss of these frugivores is expected to trigger negative cascading effects on plant populations if remnant species fail to replace the seed dispersal services provided by the extinct frugivores. A collapse of seed dispersal may not only affect plant demography (i.e., lack of recruitment), but should also supress gene flow via seed dispersal. Yet little empirical data still exist demonstrating the genetic consequences of defaunation for animal-dispersed plant species. Here, we first document a significant reduction of seed dispersal distances along a gradient of human-driven defaunation, with increasing loss of large- and medium-bodied frugivores. We then show that local plant neighbourhoods have higher genetic similarity, and smaller effective population sizes when large seed dispersers become extinct (i.e., only small frugivores remain) or are even partially downgraded (i.e., medium-sized frugivores providing less efficient seed dispersal). Our results demonstrate that preservation of large frugivores is crucial to maintain functional seed dispersal services and their associated genetic imprints, a central conservation target. Early signals of reduced dispersal distances that accompany the Anthropogenic defaunation forecast multiple, cascading effects on plant populations. PMID:27091677

  8. The signatures of Anthropocene defaunation: cascading effects of the seed dispersal collapse.

    PubMed

    Pérez-Méndez, Néstor; Jordano, Pedro; García, Cristina; Valido, Alfredo

    2016-01-01

    Anthropogenic activity is driving population declines and extinctions of large-bodied, fruit-eating animals worldwide. Loss of these frugivores is expected to trigger negative cascading effects on plant populations if remnant species fail to replace the seed dispersal services provided by the extinct frugivores. A collapse of seed dispersal may not only affect plant demography (i.e., lack of recruitment), but should also supress gene flow via seed dispersal. Yet little empirical data still exist demonstrating the genetic consequences of defaunation for animal-dispersed plant species. Here, we first document a significant reduction of seed dispersal distances along a gradient of human-driven defaunation, with increasing loss of large- and medium-bodied frugivores. We then show that local plant neighbourhoods have higher genetic similarity, and smaller effective population sizes when large seed dispersers become extinct (i.e., only small frugivores remain) or are even partially downgraded (i.e., medium-sized frugivores providing less efficient seed dispersal). Our results demonstrate that preservation of large frugivores is crucial to maintain functional seed dispersal services and their associated genetic imprints, a central conservation target. Early signals of reduced dispersal distances that accompany the Anthropogenic defaunation forecast multiple, cascading effects on plant populations. PMID:27091677

  9. The effects of self-interstitial clusters on cascade defect evolution beyond the primary damage state

    SciTech Connect

    Heinisch, H.L.

    1997-04-01

    The intracascade evolution of the defect distributions of cascades in copper is investigated using stochastic annealing simulations applied to cascades generated with molecular dynamics (MD). The temperature and energy dependencies of annihilation, clustering and free defect production are determined for individual cascades. The annealing simulation results illustrate the strong influence on intracascade evolution of the defect configuration existing in the primary damage state. Another factor significantly affecting the evolution of the defect distribution is the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades. This phenomenon introduces a cascade energy dependence of defect evolution that is apparent only beyond the primary damage state, amplifying the need for further study of the annealing phase of cascade evolution and for performing many more MD cascade simulations at higher energies.

  10. Effects of sleep disruption and high fat intake on glucose metabolism in mice.

    PubMed

    Ho, Jacqueline M; Barf, R Paulien; Opp, Mark R

    2016-06-01

    Poor sleep quality or quantity impairs glycemic control and increases risk of disease under chronic conditions. Recovery sleep may offset adverse metabolic outcomes of accumulated sleep debt, but the extent to which this occurs is unclear. We examined whether recovery sleep improves glucose metabolism in mice subjected to prolonged sleep disruption, and whether high fat intake during sleep disruption exacerbates glycemic control. Adult male C57BL/6J mice were subjected to 18-h sleep fragmentation daily for 9 days, followed by 1 day of recovery. During sleep disruption, one group of mice was fed a high-fat diet (HFD) while another group was fed standard laboratory chow. Insulin sensitivity and glucose tolerance were assessed by insulin and glucose tolerance testing at baseline, after 3 and 7 days of sleep disruption, and at the end of the protocol after 24h of undisturbed sleep opportunity (recovery). To characterize changes in sleep architecture that are associated with sleep debt and recovery, we quantified electroencephalogram (EEG) recordings during sleep fragmentation and recovery periods from an additional group of mice. We now report that 9 days of 18-h daily sleep fragmentation significantly reduces rapid eye movement sleep (REMS) and non-rapid eye movement sleep (NREMS). Mice respond with increases in REMS, but not NREMS, during the daily 6-h undisturbed sleep opportunity. However, both REMS and NREMS increase significantly during the 24-h recovery period. Although sleep disruption alone has no effect in this protocol, high fat feeding in combination with sleep disruption impairs glucose tolerance, effects that are reversed by recovery sleep. Insulin sensitivity modestly improves after 3 days of sleep fragmentation and after 24h of recovery, with significantly greater improvements in mice exposed to HFD during sleep disruption. Improvements in both glucose tolerance and insulin sensitivity are associated with NREMS rebound, raising the possibility that this

  11. SERF: A Simple, Effective, Robust, and Fast Image Super-Resolver From Cascaded Linear Regression.

    PubMed

    Hu, Yanting; Wang, Nannan; Tao, Dacheng; Gao, Xinbo; Li, Xuelong

    2016-09-01

    Example learning-based image super-resolution techniques estimate a high-resolution image from a low-resolution input image by relying on high- and low-resolution image pairs. An important issue for these techniques is how to model the relationship between high- and low-resolution image patches: most existing complex models either generalize hard to diverse natural images or require a lot of time for model training, while simple models have limited representation capability. In this paper, we propose a simple, effective, robust, and fast (SERF) image super-resolver for image super-resolution. The proposed super-resolver is based on a series of linear least squares functions, namely, cascaded linear regression. It has few parameters to control the model and is thus able to robustly adapt to different image data sets and experimental settings. The linear least square functions lead to closed form solutions and therefore achieve computationally efficient implementations. To effectively decrease these gaps, we group image patches into clusters via k-means algorithm and learn a linear regressor for each cluster at each iteration. The cascaded learning process gradually decreases the gap of high-frequency detail between the estimated high-resolution image patch and the ground truth image patch and simultaneously obtains the linear regression parameters. Experimental results show that the proposed method achieves superior performance with lower time consumption than the state-of-the-art methods. PMID:27323364

  12. Early neuroendocrine disruption in hypothalamus and hippocampus: developmental effects including female sexual maturation and implications for endocrine disrupting chemical screening.

    PubMed

    Bourguignon, J-P; Franssen, D; Gérard, A; Janssen, S; Pinson, A; Naveau, E; Parent, A-S

    2013-11-01

    The timing of puberty has been mainly studied in females for several reasons, including the possible evaluation of a precise timer (i.e. menarcheal age) and concerns with respect to the high prevalence of precocity in females as opposed to males. Human evidence of altered female pubertal timing after exposure to endocrine disrupting chemicals (EDCs) is equivocal. Among the limiting factors, most studies evaluate exposure to single EDCs at the time of puberty and hardly assess the impact of lifelong exposure to mixtures of EDCs. Some rodent and ovine studies indicate a possible role of foetal and neonatal exposure to EDCs, in accordance with the concept of an early origin of health and disease. Such effects possibly involve neuroendocrine mechanisms because the hypothalamus is a site where homeostasis of reproduction, as well as control of energy balance, is programmed and regulated. In our previous studies, pulsatile gonadotrophin-releasing hormone (GnRH) secretion control via oestrogen, glutamate and aryl hydrocarbon receptors was shown to be involved in the mechanism of sexual precocity after early postnatal exposure to the insecticide dichlorodiphenyltrichloroethane. Very recently, we have shown that neonatal exposure to the potent synthetic oestrogen diethylstilbestrol (DES) is followed by early or delayed puberty depending on the dose, with consistent changes in developmental increase of GnRH pulse frequency. Moreover, DES results in reduced leptin stimulation of GnRH secretion in vitro, an effect that is additive with prenatal food restriction. Thus, using puberty as an endpoint of the effects of EDC, it appears necessary to consider pre- and perinatal exposure to low doses and to pay attention to the other conditions of prenatal life, such as energy availability, keeping in mind the possibility that puberty could not only be advanced, but also delayed through neuroendocrine mechanisms. PMID:24028442

  13. Computation of inverse magnetic cascades

    SciTech Connect

    Montgomery, D.

    1981-10-01

    Inverse cascades of magnetic quantities for turbulent incompressible magnetohydrodynamics are reviewed, for two and three dimensions. The theory is extended to the Strauss equations, a description intermediate between two and three dimensions appropriate to tokamak magnetofluids. Consideration of the absolute equilibrium Gibbs ensemble for the system leads to a prediction of an inverse cascade of magnetic helicity, which may manifest itself as a major disruption. An agenda for computational investigation of this conjecture is proposed.

  14. Computation of inverse magnetic cascades

    NASA Technical Reports Server (NTRS)

    Montgomery, D.

    1981-01-01

    Inverse cascades of magnetic quantities for turbulent incompressible magnetohydrodynamics are reviewed, for two and three dimensions. The theory is extended to the Strauss equations, a description intermediate between two and three dimensions appropriate to Tokamak magnetofluids. Consideration of the absolute equilibrium Gibbs ensemble for the system leads to a prediction of an inverse cascade of magnetic helicity, which may manifest itself as a major disruption. An agenda for computational investigation of this conjecture is proposed.

  15. Effects of mistuning on bending-torsion flutter and response of a cascade in incompressible flow

    SciTech Connect

    Kaza, K.R.V.; Kielb, R.E.

    1981-01-01

    An investigation of the effects of blade mistuning on the aeroelastic stability and response of a cascade in incompressible flow is reported. The aerodynamic, inertial, and structural coupling between the bending and torsional motions of each blade and the aerodynamic coupling between the blades are included in the formulation. A digital computer program was developed to conduct parametric studies. Results indicate that the mistuning has a beneficial effect on the coupled bending-torsion and uncoupled torsion flutter. The effect of mistuning on forced response, however, may be either beneficial or adverse, depending on the engine order of the forcing function. Additionally, the results illustrate that it may be feasible to utilize mistuning as a passive control to increase flutter speed while maintaining forced response at an acceptable level.

  16. Cascaded nonlinearity caused by local-field effects in the two-level atom

    SciTech Connect

    Dolgaleva, Ksenia; Boyd, Robert W.; Sipe, John E.

    2007-12-15

    Contributions to the fifth-order nonlinear optical susceptibility {chi}{sup (5)} of a collection of homogeneously broadened two-level atoms that scale as N{sup 2}({gamma}{sub at}{sup (3)}){sup 2} and N{sup 2}|{gamma}{sub at}{sup (3)}|{sup 2}, where {gamma}{sub at}{sup (3)} is the lower-order atomic hyperpolarizability and N is the atomic number density, are predicted theoretically. These 'cascaded' contributions are a consequence of local-field effects. We determine them from a fifth-order solution of the Lorentz-Maxwell-Bloch equations. They are missing from a straightforward generalization of Bloembergen's result for the local field correction to the second order nonlinearity, but are recovered by a careful application of his general approach. We find that at high atomic densities (N>10{sup 15} cm{sup -3}) the value of the cascaded third-order contribution can be as large as the 'direct' fifth-order term in the expression for the fifth-order susceptibility.

  17. Stochastic Gyroresonant Acceleration for Hard Electron Spectra of Blazars: Effect of Damping of Cascading Turbulence

    NASA Astrophysics Data System (ADS)

    Kakuwa, Jun

    2016-01-01

    Stochastic acceleration of nonthermal electrons is investigated in the context of hard photon spectra of blazars. It is well known that this acceleration mechanism can produce a hard electron spectrum of m≡ ∂ {ln}{n}{{e}}(γ )/∂ {ln}γ =2 with the high-energy cutoff, called an ultrarelativistic Maxwellian-like distribution, where {n}{{e}}(γ ) is an electron energy spectrum. We revisit the formation of this characteristic spectrum, considering a particular situation where the electrons are accelerated through gyroresonant interaction with magnetohydrodynamic wave turbulence driven by the turbulent cascade. By solving kinetic equations of the turbulent fields, electrons, and photons emitted via the synchrotron self-Compton (SSC) process, we demonstrate that in the non-test-particle treatment, the formation of a Maxwellian-like distribution is prevented by the damping effect on the turbulent fields due to the electron acceleration, at least unless an extreme parameter value is chosen. Instead, a softer electron spectrum with the index of m ≈ -1 is produced if the Kolmogorov-type cascade is assumed. The SSC spectrum that originates from the resultant softer electron spectrum is still hard, but somewhat softer and broader than the case of m = 2. This change of achievable hardness should be noted when this basic particle acceleration scenario is accurately tested with observations of hard photon spectra.

  18. Quantum cascade emission in the III-nitride material system designed with effective interface grading

    SciTech Connect

    Song, Alex Y. Huang, Tzu-Yung; Zah, Chung-En; Gmachl, Claire F.; Bhat, Rajaram; Wang, Jie; Allerman, Andrew A.

    2015-09-28

    We report the realization of quantum cascade (QC) light emission in the III-nitride material system, designed with effective interface grading (EIG). EIG induces a continuous transition between wells and barriers in the quantum confinement, which alters the eigenstate system and even delocalizes the states with higher energy. Fully transverse-magnetic spontaneous emission is observed from the fabricated III-nitride QC structure, with a center wavelength of ∼4.9 μm and a full width at half maximum of ∼110 meV, both in excellent agreement with theoretical predictions. A multi-peak photo-response spectrum is also measured from the QC structure, which again agrees well with theoretical calculations and verifies the effects of EIG.

  19. Developmental effects of dioxins and related endocrine disrupting chemicals.

    PubMed

    Birnbaum, L S

    1995-12-01

    Alteration of hormones has long been known to affect development. TCDD and related PHAHs modulate the levels of many hormonal systems. Dioxins cause a spectrum of morphological and functional developmental deficits. Fetotoxicity, thymic atrophy, and structural malformations are often noted. Delayed genitourinary tract effects have been observed, and recent studies reported behavioral effects. Highly exposed human offspring have exhibited developmental problems as well. Recently, hormonal and neurological abnormalities have been reported in infants from the general population. The complex alteration of multiple endocrine systems is likely associated with the spectrum of adverse developmental effects caused by dioxin and related compounds. PMID:8597137

  20. Characterization of Energy Conservation in Primary Knock-On Atom Cascades: Ballistic Phase Effects on Variable Time Steps

    SciTech Connect

    Corrales, Louis R.; Devanathan, Ram

    2006-09-01

    Non-equilibrium molecular dynamics simulation trajectories must in principle conserve energy along the entire path. Processes exist in high-energy primary knock-on atom cascades that can affect the energy conservation, specifically during the ballistic phase where collisions bring atoms into very close proximities. The solution, in general, is to reduce the time step size of the simulation. This work explores the effects of variable time step algorithms and the effects of specifying a maximum displacement. The period of the ballistic phase can be well characterized by methods developed in this work to monitor the kinetic energy dissipation during a high-energy cascade.

  1. Biomonitoring and Hormone-Disrupting Effect Biomarkers of Persistent Organic Pollutants In Vitro and Ex Vivo

    PubMed Central

    Bonefeld-Jørgensen, Eva C; Ghisari, Mandana; Wielsøe, Maria; Bjerregaard-Olesen, Christian; Kjeldsen, Lisbeth S; Long, Manhai

    2014-01-01

    Persistent organic pollutants (POPs) include lipophilic legacy POPs and the amphiphilic perfluorinated alkyl acids (PFAAs). They have long half-lives and bioaccumulate in the environment, animals and human beings. POPs possess toxic, carcinogenic and endocrine-disrupting potentials. Endocrine-disrupting chemicals (EDCs) are compounds that either mimic or block endogenous hormones and thus disrupt the normal hormone homeostasis. Biomonitoring assesses the internal doses of a person to provide information about chemical exposures. Effect biomarkers assess chemicals potential to affect cellular functions in vivo/ex vivo. Human beings are exposed to complex mixtures of chemicals, having individually very different biological potentials and effects. Therefore, the assessment of the combined, integrated biological effect of the actual chemical mixture in human blood is important. In vitro and ex vivo cell systems have been introduced for the assessment of the integrated level of xenobiotic cellular effects in human beings. Ex vivo studies have shown geographical differences in bioaccumulated POP serum levels, being reflected by the combined biomarker effects of the complex mixture extracted from human serum. Xenohormone receptor transactivities can be used as an ex vivo integrated biomarker of POP exposure and effects. Epidemiological and in vitro/ex vivo studies have supported the potential impact of the combined effect of serum POPs on the activity of hormone and/or dioxin receptors as a risk factor for human health. With focus on hormone disruption, this MiniReview will give an update on recent POP-related endocrine-disrupting effects in vitro/ex vivo/in vivo and some related genetic data. PMID:24797035

  2. Cumulative effects of mothers' risk and promotive factors on daughters' disruptive behavior.

    PubMed

    van der Molen, Elsa; Hipwell, Alison E; Vermeiren, Robert; Loeber, Rolf

    2012-07-01

    Little is known about the ways in which the accumulation of maternal factors increases or reduces risk for girls' disruptive behavior during preadolescence. In the current study, maternal risk and promotive factors and the severity of girls' disruptive behavior were assessed annually among girls' ages 7-12 in an urban community sample (N = 2043). Maternal risk and promotive factors were operative at different time points in girls' development. Maternal warmth explained variance in girls' disruptive behavior, even after controlling for maternal risk factors and relevant child and neighborhood factors. In addition, findings supported the cumulative hypothesis that the number of risk factors increased the chance on girls' disruptive behavior disorder (DBD), while the number of promotive factors decreased this probability. Daughters of mothers with a history of Conduct Disorder (CD) were exposed to more risk factors and fewer promotive factors compared to daughters of mothers without prior CD. The identification of malleable maternal factors that can serve as targets for intervention has important implications for intergenerational intervention. Cumulative effects show that the focus of prevention efforts should not be on single factors, but on multiple factors associated with girls' disruptive behavior. PMID:22127641

  3. Effect of endocrine disrupters on photosystem II energy fluxes of green algae and cyanobacteria.

    PubMed

    Perron, Marie-Claude; Juneau, Philippe

    2011-05-01

    Among the numerous toxics found in the aquatic environment, endocrine disrupters can interfere with the normal functioning of the endocrine system of several organisms, leading to important consequences. Even if algae and cyanobacteria are non-target organisms without endocrine system, our goals were to verify if endocrine disrupters can affect photosynthetic activity and how energy flows through photosystem II (PSII) were altered. To reach these objectives, we exposed, for 15 min, two green algae (Chlamydomonas reinhardtii strain CC125, Pseudokirchneriella subcapitata strain CPCC37) and a toxic and a non-toxic strain of Microcystis aeruginosa (CPCC299 and CPCC632 respectively) to 4-octylphenol, 4-nonylphenol and β-estradiol at concentrations ranging from 0.1 to 5 μg/mL. We have shown for the first time that endocrine disrupters may have drastic effects on PSII energy fluxes. Furthermore, we showed that various species have different sensitivity to endocrine disrupters. P. subcapitata was tolerant to each endocrine disrupter tested, while flows of energy through PSII were affected similarly, but at different extent, for the other species. Cyanobacterial PSII energy fluxes were more affected than green algae, suggesting that the prokaryotic characteristics of these organisms are responsible of their high sensitivity. PMID:21439565

  4. Thyroid disruption effects of environmental level perfluorooctane sulfonates (PFOS) in Xenopus laevis.

    PubMed

    Cheng, Yan; Cui, Yuan; Chen, Hui-ming; Xie, Wen-ping

    2011-11-01

    Perfluorooctane sulfonate (PFOS), one of the emerging persistent organic pollutants (POPs), has caused growing international concern especially related to the potential disruption in the development and function of thyroid system. Xenopus laevis is an amphibian species widely used as a suitable amphibian model for thyroid disruption research. To study the thyroid disruption effects related to PFOS exposure at environmental low levels, X. laevis tadpoles were exposed to 0.1, 1, 10 and 100 μg/l PFOS in water respectively from stage 46/47 to stage 62. The results showed that the time to metamorphosis (presented by forelimb emergence, FLE) did not significantly change with PFOS exposure, but exhibited an increasing trend (except for 10 μg/l exposure). Partial colloid depletion was observed for PFOS exposure, but no significant histological abnormality was observed in treatment groups. In addition, PFOS exposure resulted in up-regulation of thyroid hormone-regulated genes-thyroid receptor beta A (TRβA), basic transcription element-binding protein (BTEB) and type II deiodinase (DI2) mRNA expression, presented as an inverted U-shaped dose response pattern. However, the mRNA expression of type III deiodinase (DI3) remained unaffected compared with the control. These results demonstrated that PFOS might disrupt the thyroid system in X. laevis tadpoles regarding FLE changes and regulation alternation of thyroid hormone-regulated genes. Our study has raised new concerns for possible thyroid disruption of PFOS in amphibians at environmental relevant levels. PMID:21809121

  5. Impact of temporal, spatial and cascaded effects on the pulse formation in ultra-broadband parametric amplifiers.

    PubMed

    Lang, T; Harth, A; Matyschok, J; Binhammer, T; Schultze, M; Morgner, U

    2013-01-14

    A 2 + 1 dimensional nonlinear pulse propagation model is presented, illustrating the weighting of different effects for the parametric amplification of ultra-broadband spectra in different regimes of energy scaling. Typical features in the distribution of intensity and phase of state-of-the-art OPA-systems can be understood by cascaded spatial and temporal effects. PMID:23388988

  6. Images of plasma disruption effects in the Tokamak Fusion Test Reactor

    SciTech Connect

    Maqueda, R.J.; Wurden, G.A.

    1999-02-01

    Fast-framing imaging of visible radiation from magnetically confined plasmas has lately become a useful tool for both machine operation and physics studies. Using an intensified, commercial Kodak Ektapro imaging system, the effects of a plasma disruption were observed in the Tokamak Fusion Test Reactor (TFTR). The high-energy runaway electrons created soon after the disruption collide with the plasma facing components damaging this surface and producing a shower of debris that traverses the toroidal vessel and falls over the inner bumper limiter.

  7. Developmental effects of endocrine-disrupting chemicals in wildlife and humans.

    PubMed Central

    Colborn, T; vom Saal, F S; Soto, A M

    1993-01-01

    Large numbers and large quantities of endocrine-disrupting chemicals have been released into the environment since World War II. Many of these chemicals can disturb development of the endocrine system and of the organs that respond to endocrine signals in organisms indirectly exposed during prenatal and/or early postnatal life; effects of exposure during development are permanent and irreversible. The risk to the developing organism can also stem from direct exposure of the offspring after birth or hatching. In addition, transgenerational exposure can result from the exposure of the mother to a chemical at any time throughout her life before producing offspring due to persistence of endocrine-disrupting chemicals in body fat, which is mobilized during egg laying or pregnancy and lactation. Mechanisms underlying the disruption of the development of vital systems, such as the endocrine, reproductive, and immune systems, are discussed with reference to wildlife, laboratory animals, and humans. PMID:8080506

  8. Developmental effects of endocrine-disrupting chemicals in wildlife and humans

    SciTech Connect

    Colborn, T. ); vom Saal, F.S. ); Soto, A.M. )

    1993-10-01

    Large numbers and large quantities of endoncrine-disrupting chemicals have been released into the environment since World War II. Many of these chemicals can disturb development of the endocrine system and of the organs that respond to endocrine signals in organisms indirectly exposed during prenatal and/or early postnatal life; effects of exposure during development are permanent and irreversible. The risk to the developing organism can also stem from direct exposure of the offspring after birth or hatching. In addition, trangenerational exposure can result from the exposure of the mother to a chemical at any time throughout her life before producing offspring due to persistent of endocrine-disrupting chemicals in body fat, which is mobilized during egg laying or pregnancy and lactation. Mechanisms underlying the disruption of the development of vital systems, such as the endocrine, reproductive, and immune systems, are discussed with reference to wildlife, laboratory animals, and humans.

  9. ENDOCRINE-DISRUPTING CHEMICALS IN THE ENVIRONMENT: ASSESSING POTENTIAL EFFECTS IN WILDLIFE

    EPA Science Inventory

    Recent evidence suggests that xenobiotic chemicals which mimic/block the action of key hormones in a variety of endocrine pathways may be responsible for adverse effects both in humans and wildlife. This talk will provide an overview of instances in which endocrine-disrupting che...

  10. Effectiveness of Noncontingent Attention to Decrease Attention-Maintained Disruptive Behaviors in the General Education Classroom

    ERIC Educational Resources Information Center

    Banda, Devender R.; Sokolosky, Stephanie

    2012-01-01

    This study was conducted to investigate the effectiveness of noncontingent attention (NCA) on disruptive talking-out behavior in a student diagnosed with attention deficit and hyperactivity disorder in the general education classroom. Functional analysis indicated that the talking-out behavior was maintained by teacher attention. We used an ABAB…

  11. Effectiveness of a Competence Training Programme for Parents of Socially Disruptive Children

    ERIC Educational Resources Information Center

    Lauth, Gerhard W.; Otte, T. Alian; Heubeck, Bernd G.

    2009-01-01

    Modern evaluations of parent training programmes seek evidence not only of efficacy in optimal, often university clinic settings, but also of effectiveness under normal field conditions. The Kompetenztraining fur Eltern sozial auffalliger Kinder (KES) is a cognitive-behavioural competence training for parents of socially disruptive children. This…

  12. Depressant Effects of Salvia divinorum Involve Disruption of Physiological Sleep.

    PubMed

    González-Trujano, María Eva; Brindis, Fernando; López-Ruiz, Edith; Ramírez-Salado, Ignacio; Martínez, Adrián; Pellicer, Francisco

    2016-07-01

    Although Salvia divinorum is traditionally known as a 'mind-altering' or psychoactive herb used, among others things, as a tranquilizer, this property has not been validated with regard to its efficacy and safety. The objective of this study is to provide evidence for the sedative effects of S. divinorum and discriminate the nature of the responsible constituents by examining different experimental models. A battery of tests, including the open-field, hole-board, exploration cylinder, plus-maze and sodium pentobarbital-induced hypnosis potentiation, were used in mice after administration of non-polar, medium polar and/or polar extracts of the plant (10, 30 and 100 mg/kg). Polysomnographic analysis in rats receiving an active medium polar extract (10 and 100 mg/kg) containing salvinorins was also assessed to study the effects of this plant on sleep architecture. All tested extracts produced significant sedative-like responses, although those of the medium polar extract were more pronounced in mice. The sedative effect of this latter extract, which contains a mixture of salvinorins, caused fragmented sleep architecture in rats by diminishing rapid eye movement (REM) sleep and increased the quiet awake stage at 10 and 100 mg/kg. Our results provide evidence that S. divinorum exhibits sedative-like depressant properties that alter physiological sleep architecture. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27037508

  13. Effects of fluorotelomer alcohol 8:2 FTOH on steroidogenesis in H295R cells: Targeting the cAMP signalling cascade

    SciTech Connect

    Liu Chunsheng; Zhang Xiaowei; Chang Hong; Jones, Paul; Wiseman, Steve; Naile, Jonathan; Hecker, Markus; Giesy, John P.; Zhou Bingsheng

    2010-09-15

    Previous studies have demonstrated that perfluorinated chemicals (PFCs) can affect reproduction by disruption of steroidogenesis in experimental animals. However, the underlying mechanism(s) of this disruption remain unknown. Here we investigated the effects and mechanisms of action of 1H, 1H, 2H, 2H-perfluoro-decan-1-ol (8:2 FTOH) on steroidogenesis using a human adrenocortical carcinoma cell line (H295R) as a model. H295R cells were exposed to 0, 7.4, 22.2 or 66.6 {mu}M 8:2 FTOH for 24 h and productions of progesterone, 17{alpha}-OH-progesterone, androstenedione, testosterone, deoxycorticosterone, corticosterone and cortisol were quantified by HPLC-MS/MS. With the exception of progesterone, 8:2 FTOH treatment significantly decreased production of all hormones in the high dose group. Exposure to 8:2 FTOH significantly down-regulated cAMP-dependent mRNA expression and protein abundance of several key steroidogenic enzymes, including StAR, CYP11A, CYP11B1, CYP11B2, CYP17 and CYP21. Furthermore, a dose-dependent decrease of cellular cAMP levels was observed in H295R cells exposed to 8:2 FTOH. The observed responses are consistent with reduced cellular cAMP levels. Exposure to 8:2 FTOH resulted in significantly less basal (+ GTP) and isoproterenol-stimulated adenylate cyclase activities, but affected neither total cellular ATP level nor basal (-GTP) or NaF-stimulated adenylate cyclase activities, suggesting that inhibition of steroidogenesis may be due to an alteration in membrane properties. Metabolites of 8:2 FTOH were not detected by HPLC-MS/MS, suggesting that 8:2 FTOH was not metabolized by H295R cells. Overall, the results show that 8:2 FTOH may inhibit steroidogenesis by disrupting the cAMP signalling cascade.

  14. Secondary flows in annular cascades and effects on flow in inlet guide vanes

    NASA Technical Reports Server (NTRS)

    Lieblein, Seymour; Ackley, Richard H

    1951-01-01

    Qualitative discussion is presented of the general nature of secondary flows in stationary annular cascades with thin wall boundary layers and radial design variation of circulation. Deviations from ideal mean outlet flows (based on blade-element performance) exist in potential-flow region of vanes because of conditions imposed by end-wall boundaries, displacement of wall boundary layers toward blade suction surfaces, and irrotationality requirement. As a consequence of existence of nonuniform radial flow across blade spacing, it may not generally be possible to obtain an arbitrarily specified design variation of the turning angle along the radial height of a blade row. Quantitative turning angle corrections due to effects of secondary flows in axial-flow compressor inlet guide vanes were obtained from induced deflections of a superimposed vortex system in conjunction with an empirically determined correlation factor.

  15. Effective utilization of quantum-cascade distributed-feedback lasers in absorption spectroscopy

    NASA Technical Reports Server (NTRS)

    Kosterev, A. A.; Curl, R. F.; Tittel, F. K.; Gmachl, C.; Capasso, F.; Sivco, D. L.; Baillargeon, J. N.; Hutchinson, A. L.; Cho, A. Y.

    2000-01-01

    A variable duty cycle quasi-cw frequency scanning technique was applied to reduce thermal effects resulting from the high heat dissipation of type I quantum-cascade lasers. This technique was combined with a 100-m path-length multipass cell and a zero-air background-subtraction technique to enhance detection sensitivity to a parts-in-10(9) (ppb) concentration level for spectroscopic trace-gas detection of CH4, N2O, H2O, and C2H5OH in ambient air at 7.9 micrometers. A new technique for analysis of dense high resolution absorption spectra was applied to detection of ethanol in ambient air, yielding a 125-ppb detection limit.

  16. Cascading Effects: The Influence of Attention Bias to Threat on the Interpretation of Ambiguous Information

    PubMed Central

    White, Lauren K.; Suway, Jenna G.; Pine, Daniel S.; Bar-Haim, Yair; Fox, Nathan A.

    2011-01-01

    Both attention bias to threat and negative interpretive bias have been implicated in the emergence and maintenance of anxiety disorders. However, relations between attention and interpretive biases remain poorly understood. The current study experimentally manipulated attention bias to threat and examined the effects of attention training on the way ambiguous information was interpreted. Results suggest that the preferential allocation of attention towards threat affects the manner in which ambiguous information is interpreted. Individuals trained to attend to threat were more likely than individuals in a placebo training group to interpret ambiguous information in a threat-related manner. These data suggest that perturbations in the initial stages of information processing associated with anxiety may lead to a cascade of subsequent processing biases. PMID:21353663

  17. Cascade-coupled racetrack resonators based on the Vernier effect in the mid-infrared.

    PubMed

    Troia, Benedetto; Khokhar, Ali Z; Nedeljkovic, Milos; Penades, Jordi Soler; Passaro, Vittorio M N; Mashanovich, Goran Z

    2014-10-01

    In this paper we report the experimental demonstration of racetrack resonators in silicon-on-insulator technology platform operating in the mid-infrared wavelength range of 3.7-3.8 μm. Insertion loss lower than 1 dB and extinction ratio up to 30 dB were measured for single resonators. The experimental characterization of directional couplers and bending losses in silicon rib waveguides are also reported. Furthermore, we present the design and fabrication of cascade-coupled racetrack resonators based on the Vernier effect. Experimental spectra of Vernier architectures were demonstrated for the first time in the mid-infrared with insertion loss lower than 1 dB and maximum interstitial peak suppression of 10 dB. PMID:25321975

  18. Prey size structure diminishes cascading effects by increasing interference competition and predation among prey.

    PubMed

    Geraldii, Nathan R

    2015-09-01

    The size of an organism can change by orders of magnitude during its lifespan. Size can determine whether an individual consumes, is consumed, competes, or avoids individuals of the same or different species. Two complementary mesocosm experiments with a tri-trophic food chain (top predator, toadfish, Opsanus tau; intermediate prey, mud crab, family Xanthidae; basal resource, oyster, Crassostrea virginica) were conducted to measure how the size of both the top predator and the intermediate prey affects consumptive and behavioral interactions in trophic cascades. In the first experiment, I systematically varied the sizes of predators and prey, respectively. The amount of crab biomass consumed was dependent on crab size and not toadfish size, but the effect of crab size did not cascade to alter oyster survival. Increased oyster survival from crab interference competition in the absence of toadfish was similar to oyster survival,from predator-avoidance behavior in the presence of a toadfish. When all crab size classes were present, crab mortality was similar in the presence and absence of toadfish, highlighting the importance of intraguild predation in food-web dynamics. The second experiment separated crab mortality by other crabs from crab mortality by predatory toadfish and found that crab mortality generally switched from intra- to interguild predation when a toadfish was present. In addition, field surveys indicated mud crab abundance and size was primarily influenced by mud crab recruitment, but not by toadfish abundance, which supports our experimental results that interactions among mud crabs have similar effects to predator-prey interactions. These findings indicate that changes in size or abundance of intermediate prey may be comparable to changes in top predator abundance in terms of trophic interactions and their transmission to lower levels, which suggests that certain types of relatively simple food chains can be resilient to the loss of higher trophic

  19. Detecting the effects of cascade hydropower reservoirs on eco-flow metrics

    NASA Astrophysics Data System (ADS)

    Zhao, T.; Zhao, J.

    2012-12-01

    Over evolutionary time, the natural hydrological events of floods and droughts have become an integral component of riverine ecosystems. However, human activities, particularly reservoir operations, can greatly alter the natural flow regime and pose great impacts on riverine ecosystems. This study analyses the effects of cascade hydropower reservoir operation on eco-flow metrics based on inflow and release data of reservoirs in southwest China, with a focus on the Xiaowan reservoir (upper reservoir with multi-annual storage capacity) and the Jinghong reservoir (lower reservoir with weekly storage capacity). For the upper Xiaowan Reservoir, the analysis results show that the eco-surplus and eco-deficit (Vogel, et al, 2007; Gao, et al., 2009 ) can capture its impacts of hydropower operation on eco-flow metrics very well. However, comparative analysis of the lower Jinghong reservoir based on daily and hourly data shows that eco-surplus and eco-deficit measured with flow duration curve of daily and hourly flow data are not sensitive indices, which is attributed to the small regulating capacity of the Jinghong reservoir. It is shown that the negative impacts of hydropower operation of the Jinghong reservoir can be characterized by the changing rate of flow. These results indicate that eco-surplus and eco-deficit are good representative indices for evaluating seasonal reservoir operation, but more attention should be paid to the changing rate of flow for short term hydropower reservoir operation. This study implies that coordination of cascade reservoirs can be an effective way to mitigate the negative impacts of hydropower operation on ecosystem.

  20. Do we know which interventions are effective for disruptive and delinquent girls?

    PubMed

    Hipwell, Alison E; Loeber, Rolf

    2006-12-01

    Disruptive and delinquent girls are not well served by the mental health and juvenile justice systems. Interventions that have been developed for the behavior problems of boys are frequently applied to girls despite growing evidence for a female-specific phenotype, developmental course, and set of risk factors from middle childhood onwards. The current review demonstrates that evidence of the effectiveness of treatments for girls with disruptive and delinquent behaviors is extremely limited, with relatively few studies including sufficient numbers of females or reporting on treatment effects by gender. However, a small body of evidence suggests that interventions specifically designed to address female behavior problems or risk factors can be effective in ameliorating disruptive and delinquent behaviors in both pre-adolescence and adolescence. Multi-modal interventions that target interacting domains of risk also show promise. Methodological issues are discussed and recommendations are made for the development and evaluation of future interventions to prevent and reduce girls' disruptive and delinquent behavior. PMID:17139554

  1. Disrupting effect of androgens in postnatal female domestic cats.

    PubMed

    Demaldé, Lucía; Lopez Merlo, Mariana; Vercellini, Rosario; Barbeito, Claudio G; Fernandez, Patricia; Gobello, Cristina

    2016-08-01

    To test the hypothesis that in domestic cats, postnatal androgens induce sterility, the aims of this study were to describe the reproductive effects and the clinical safety of a postnatal administration of a long term release androgen in this species. Thirteen newborn littermate female kittens were randomly assigned to one of the following treatment groups within the first 24h of birth: testosterone enanthate 12.5mg sc (TE; n=8) or Placebo (PL; n=5). The animals were subsequently assessed for fecal sexual hormones until puberty was attained and subsequently when matings occurred. After 21 days, ovulation and gestation were diagnosed. All queens were subsequently ovario-hysterectomized. Fecal testosterone concentrations differed between the treatment groups throughout the study period (P<0.05) being greater during the first 2 postnatal weeks in those of the TE group (P<0.01). Fecal estradiol was not affected by treatment (P>0.1). While all the females were receptive during the pubertal estrus (P>0.1), two TE (2/8) compared with all (5/5) females of the PL group had ovulations (P<0.05). Only one (1/2) compared with three (3/5) of the queens of the TE and PL groups, respectively became pregnant. All kittens of the TE group had transient clitoral enlargement. Anovulatory TE-treated cats had no corpus luteum, and a significant diminution of the endometrial glands as well as of the height of the uterine epithelium. It is concluded that, in domestic cats, a single postnatal supra-physiological dose of testosterone caused a large proportion of queens to be anovulatory and there were also histological endometrial abnormalities that also occurred with this treatment that were accompanied by mild and transient side effects. PMID:27305841

  2. [Effect of antihypoxant actovegin on dynamics of markers of the oxygen cascade].

    PubMed

    Pavlov, O O

    2008-09-01

    The analysis of actovegin impact on the blood indices dynamics was performed. Immediate activation of transport chain of the oxygen cascade in all groups of investigation was noted. Antihypoxic mechanism of actovegin action through normalization of concentration and transport elements of the oxygen cascade was proved. PMID:19275037

  3. The aerodynamic effect of fillet radius in a low speed compressor cascade. Thesis - Von Karman Inst. for Fluid Dynamics

    NASA Technical Reports Server (NTRS)

    Curlett, Brian P.

    1991-01-01

    The aerodynamic effects of fillet size in a low speed compressor cascade were experimentally studied. Two blade profiles were used during the experiment, namely a controlled diffusion blade and a double circular arc blade. Cascades were tested with three fillet radii and two boundary layer thicknesses over a large range of incidence angles. The cascade performance was determined by extensive downstream flow measurements using a two head, 5 hole pressure probe. Results differ significantly between the two types of blades tested. As fillet radius increases secondary flows and total pressure losses were found to increase for the controlled diffusion blades; whereas, for the double circular arc blades the losses decrease, particularly at high incidence angles.

  4. Effect of electron divergence in air gaps on the measurement of the energy of cascades in emulsion chambers

    NASA Technical Reports Server (NTRS)

    Apanasenko, A. V.; Baradzey, L. T.; Kanevskaya, Y. A.; Smorodin, Y. A.

    1975-01-01

    The effect of an increase in electron density in the vicinity of the cascade axis caused by an avalanche passing through the gap between lead filters of the emulsion chamber was investigated experimentally. Optical densities were measured in three X-ray films spaced at 400, 800 and 1200 micrometer from the filter surface having a thickness of 6 cascade units. The optical densities of blackening spots caused by electron photon cascades of 1 to 2, 2 to 7 and greater than 7 BeV energies were measured. The results prove the presence of a gap between the filter and the nuclear emulsion which results in the underestimation of energy by several tenths of a percent.

  5. Marijuana extracts possess the effects like the endocrine disrupting chemicals.

    PubMed

    Watanabe, Kazuhito; Motoya, Erina; Matsuzawa, Naoki; Funahashi, Tatsuya; Kimura, Toshiyuki; Matsunaga, Tamihide; Arizono, Koji; Yamamoto, Ikuo

    2005-01-31

    The progesterone 17alpha-hydroxylase activity, which is one of the steroidogenic enzymes in rat testis microsomes, was significantly inhibited by crude marijuana extracts from Delta(9)-tetrahydrocannabinolic acid (THCA)- and cannabidiolic acid (CBDA)-strains. Delta(9)-Tetrahydrocannabinol, cannabidiol and cannabinol also inhibited the enzymatic activity with relatively higher concentration (100-1000 microM). Testosterone 6beta- and 16alpha-hydroxylase activities together with androstenedione formation from testosterone in rat liver microsomes were also significantly inhibited by the crude marijuana extracts and the cannabinoids. Crude marijuana extracts (1 and 10 microg/ml) of THCA strain stimulated the proliferation of MCF-7 cells, although the purified cannabinoids (THC, CBD and CBN) did not show significant effects, such as the extract at the concentration of 0.01-1000 nM. These results indicate that there are some metabolic interactions between cannabinoid and steroid metabolism and that the constituents showing estrogen-like activity exist in marijuana. PMID:15588936

  6. Aerodynamic Investigation of Incidence Angle Effects in a Large Scale Transonic Turbine Cascade

    NASA Technical Reports Server (NTRS)

    McVetta, Ashlie B.; Giel, Paul W.; Welch, Gerard E.

    2013-01-01

    Aerodynamic measurements showing the effects of large incidence angle variations on an HPT turbine blade set are presented. Measurements were made in NASA's Transonic Turbine Blade Cascade Facility which has been used in previous studies to acquire detailed aerodynamic and heat transfer measurements for CFD code validation. The current study supports the development of variable-speed power turbine (VSPT) speed-change technology for the NASA Large Civil Tilt Rotor (LCTR) vehicle. In order to maintain acceptable main rotor propulsive efficiency, the VSPT operates over a nearly 50 percent speed range from takeoff to altitude cruise. This results in 50deg or more variations in VSPT blade incidence angles. The cascade facility has the ability to operate over a wide range of Reynolds numbers and Mach numbers, but had to be modified in order to accommodate the negative incidence angle variation required by the LCTR VSPT operation. Using existing blade geometry with previously acquired aerodynamic data, the tunnel was re-baselined and the new incidence angle range was exercised. Midspan exit total pressure and flow angle measurements were obtained at seven inlet flow angles. For each inlet angle, data were obtained at five flow conditions with inlet Reynolds numbers varying from 6.83×10(exp 5) to 0.85×10(exp 5) and two isentropic exit Mach numbers of 0.74 and 0.34. The midspan flowfield measurements were acquired using a three-hole pneumatic probe located in a survey plane 8.6 percent axial chord downstream of the blade trailing edge plane and covering three blade passages. Blade and endwall static pressure distributions were also acquired for each flow condition.

  7. Aerodynamic Investigation of Incidence Angle Effects in a Large Scale Transonic Turbine Cascade. Revision 1

    NASA Technical Reports Server (NTRS)

    McVetta, Ashlie B.; Giel, Paul W.; Welch, Gerard E.

    2014-01-01

    Aerodynamic measurements showing the effects of large incidence angle variations on an HPT turbine blade set are presented. Measurements were made in NASA's Transonic Turbine Blade Cascade Facility which has been used in previous studies to acquire detailed aerodynamic and heat transfer measurements for CFD code validation. The current study supports the development of variable-speed power turbine (VSPT) speed-change technology for the NASA Large Civil Tilt Rotor (LCTR) vehicle. In order to maintain acceptable main rotor propulsive efficiency, the VSPT operates over a nearly 50 percent speed range from takeoff to altitude cruise. This results in 50 deg or more variations in VSPT blade incidence angles. The cascade facility has the ability to operate over a wide range of Reynolds numbers and Mach numbers, but had to be modified in order to accommodate the negative incidence angle variation required by the LCTR VSPT operation. Using existing blade geometry with previously acquired aerodynamic data, the tunnel was re-baselined and the new incidence angle range was exercised. Midspan exit total pressure and flow angle measurements were obtained at seven inlet flow angles. For each inlet angle, data were obtained at five flow conditions with inlet Reynolds numbers varying from 6.83×10 (exp 5) to 0.85×10(exp 5) and two isentropic exit Mach numbers of 0.74 and 0.34. The midspan flowfield measurements were acquired using a three-hole pneumatic probe located in a survey plane 8.6 percent axial chord downstream of the blade trailing edge plane and covering three blade passages. Blade and endwall static pressure distributions were also acquired for each flow condition.

  8. Aerodynamic Investigation of Incidence Angle Effects in a Large Scale Transonic Turbine Cascade

    NASA Technical Reports Server (NTRS)

    McVetta, Ashlie B.; Giel, Paul W.; Welch, Gerard E.

    2012-01-01

    Aerodynamic measurements showing the effects of large incidence angle variations on an HPT turbine blade set are presented. Measurements were made in NASA's Transonic Turbine Blade Cascade Facility which has been used in previous studies to acquire detailed aerodynamic and heat transfer measurements for CFD code validation. The current study supports the development of variable-speed power turbine (VSPT) speed-change technology for the NASA Large Civil Tilt Rotor (LCTR) vehicle. In order to maintain acceptable main rotor propulsive efficiency, the VSPT operates over a nearly 50% speed range from takeoff to altitude cruise. This results in 50 degrees or more variations in VSPT blade incidence angles. The cascade facility has the ability to operate over a wide range of Reynolds numbers and Mach numbers, but had to be modified in order to accommodate the negative incidence angle variation required by the LCTR VSPT operation. Using existing blade geometry with previously acquired aerodynamic data, the tunnel was re-baselined and the new incidence angle range was exercised. Midspan exit total pressure and flow angle measurements were obtained at seven inlet flow angles. For each inlet angle, data were obtained at five flow conditions with inlet Reynolds numbers varying from 6.83 × 10(exp 5) to 0.85 ×10(exp 5) and two isentropic exit Mach numbers of 0.74 and 0.34. The midspan flowfield measurements were acquired using a three-hole pneumatic probe located in a survey plane 8.6% axial chord downstream of the blade trailing edge plane and covering three blade passages. Blade and endwall static pressure distributions were also acquired for each flow condition

  9. Single-machine rescheduling with deterioration and learning effects against the maximum sequence disruption

    NASA Astrophysics Data System (ADS)

    Liu, Le; Zhou, Hong

    2015-10-01

    In this paper, we study the issue of single-machine rescheduling with linear deteriorating jobs and position-based learning effects simultaneously in response to an unexpected arrival of new jobs. The scheduling efficiency is measured in terms of the makespan, while the cost of disruption is measured in terms of the maximum difference in processing orders of the original jobs before and after disruption. By introducing the effects of deterioration and learning, the job actual processing time is defined by an increasing function of its starting time, meanwhile a decreasing function of its position. Two types of problems are considered. For the first one, the makespan is minimised subject to a limit on the maximum sequence disruption; while in the second one, a linear combination of the makespan and the maximum sequence disruption is minimised. For each problem, the polynomial solvability is demonstrated, and an efficient algorithm is then developed. Finally, extensive computational experiments are conducted to show the efficiency and running behaviours of the proposed algorithms.

  10. Near-infrared induced optical quenching effects on mid-infrared quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Guo, Dingkai; Cai, Hong; Talukder, Muhammad Anisuzzaman; Chen, Xing; Johnson, Anthony M.; Khurgin, Jacob B.; Choa, Fow-Sen

    2014-06-01

    In space communications, atmospheric absorption and Rayleigh scattering are the dominant channel impairments. Transmission using mid-infrared (MIR) wavelengths offers the benefits of lower loss and less scintillation effects. In this work, we report the telecom wavelengths (1.55 μm and 1.3 μm) induced optical quenching effects on MIR quantum cascade lasers (QCLs), when QCLs are operated well above their thresholds. The QCL output power can be near 100% quenched using 20 mW of near-infrared (NIR) power, and the quenching effect depends on the input NIR intensity as well as wavelength. Time resolved measurement was conducted to explore the quenching mechanism. The measured recovery time is around 14 ns, which indicates that NIR generated electron-hole pairs may play a key role in the quenching process. The photocarrier created local field and band bending can effectively deteriorate the dipole transition matrix element and quench the QCL. As a result, MIR QCLs can be used as an optical modulator and switch controlled by NIR lasers. They can also be used as "converters" to convert telecom optical signals into MIR optical signals.

  11. Near-infrared induced optical quenching effects on mid-infrared quantum cascade lasers

    SciTech Connect

    Guo, Dingkai Talukder, Muhammad Anisuzzaman; Chen, Xing; Cai, Hong; Johnson, Anthony M.; Choa, Fow-Sen; Khurgin, Jacob B.

    2014-06-23

    In space communications, atmospheric absorption and Rayleigh scattering are the dominant channel impairments. Transmission using mid-infrared (MIR) wavelengths offers the benefits of lower loss and less scintillation effects. In this work, we report the telecom wavelengths (1.55 μm and 1.3 μm) induced optical quenching effects on MIR quantum cascade lasers (QCLs), when QCLs are operated well above their thresholds. The QCL output power can be near 100% quenched using 20 mW of near-infrared (NIR) power, and the quenching effect depends on the input NIR intensity as well as wavelength. Time resolved measurement was conducted to explore the quenching mechanism. The measured recovery time is around 14 ns, which indicates that NIR generated electron-hole pairs may play a key role in the quenching process. The photocarrier created local field and band bending can effectively deteriorate the dipole transition matrix element and quench the QCL. As a result, MIR QCLs can be used as an optical modulator and switch controlled by NIR lasers. They can also be used as “converters” to convert telecom optical signals into MIR optical signals.

  12. In vitro thyroid disrupting effects of organic extracts from WWTPs in Beijing.

    PubMed

    Li, Na; Ma, Mei; Rao, Kaifeng; Wang, Zijian

    2011-01-01

    It is generally known that there are many endocrine disrupting compounds (EDCs) in the effluents from wastewater treatment plants (WWTPs). Most research has focused on the occurrence of estrogenic or androgenic activities, while ignoring that there are environmental chemicals disrupting thyroid system, which is essential for growth and development in both humans and animals. In the present work, a two-hybrid yeast assay was conducted to evaluate the removal efficiencies of agonistic or antagonistic thyroid receptor (TR) mediated effects in different treatment processes of three WWTPs located in Beijing. We found no TR agonistic, but TR antagonistic activities in all processes from the WWTPs. The TR antagonistic activities in organic extracts of water samples were then calibrated regarding to a known TR-inhibitor, amiodarone hydrochloride (AH). The observed concentration of TR disrupting substances ranged from 2.35 x 10(-8) to 6.19 x 10(-7) mol/L AH in Gaobeidian WWTP, 3.76 x 10(-8) to 8.75 x 10(-8) mol/L AH in Lugouqiao WWTP, and 4.80 x 10(-9) to 2.55 x 10(-8) mol/L AH in Beixiaohe WWTP. Of the three WWTPs, the removal rates were 92.7%, 42.2%, and 23.1% respectively. Industrial sewage may contain more TR disrupting substances compared with domestic sewage. The recipient waters were found to contain considerable concentrations of TR disrupting substances that may cause adverse effects on the exposed organisms. PMID:21793411

  13. Disrupting evolutionary processes: The effect of habitat fragmentation on collared lizards in the Missouri Ozarks

    PubMed Central

    Templeton, Alan R.; Robertson, Robert J.; Brisson, Jennifer; Strasburg, Jared

    2001-01-01

    Humans affect biodiversity at the genetic, species, community, and ecosystem levels. This impact on genetic diversity is critical, because genetic diversity is the raw material of evolutionary change, including adaptation and speciation. Two forces affecting genetic variation are genetic drift (which decreases genetic variation within but increases genetic differentiation among local populations) and gene flow (which increases variation within but decreases differentiation among local populations). Humans activities often augment drift and diminish gene flow for many species, which reduces genetic variation in local populations and prevents the spread of adaptive complexes outside their population of origin, thereby disrupting adaptive processes both locally and globally within a species. These impacts are illustrated with collared lizards (Crotaphytus collaris) in the Missouri Ozarks. Forest fire suppression has reduced habitat and disrupted gene flow in this lizard, thereby altering the balance toward drift and away from gene flow. This balance can be restored by managed landscape burns. Some have argued that, although human-induced fragmentation disrupts adaptation, it will also ultimately produce new species through founder effects. However, population genetic theory and experiments predict that most fragmentation events caused by human activities will facilitate not speciation, but local extinction. Founder events have played an important role in the macroevolution of certain groups, but only when ecological opportunities are expanding rather than contracting. The general impact of human activities on genetic diversity disrupts or diminishes the capacity for adaptation, speciation, and macroevolutionary change. This impact will ultimately diminish biodiversity at all levels. PMID:11344289

  14. Effects of Estrogens and Estrogenic Disrupting Compounds on Fish Mineralized Tissues

    PubMed Central

    Pinto, Patricia I. S.; Estêvão, Maria D.; Power, Deborah M.

    2014-01-01

    Estrogens play well-recognized roles in reproduction across vertebrates, but also intervene in a wide range of other physiological processes, including mineral homeostasis. Classical actions are triggered when estrogens bind and activate intracellular estrogen receptors (ERs), regulating the transcription of responsive genes, but rapid non-genomic actions initiated by binding to plasma membrane receptors were recently described. A wide range of structurally diverse compounds from natural and anthropogenic sources have been shown to interact with and disrupt the normal functions of the estrogen system, and fish are particularly vulnerable to endocrine disruption, as these compounds are frequently discharged or run-off into waterways. The effect of estrogen disruptors in fish has mainly been assessed in relation to reproductive endpoints, and relatively little attention has been given to other disruptive actions. This review will overview the actions of estrogens in fish, including ER isoforms, their expression, structure and mechanisms of action. The estrogen functions will be considered in relation to mineral homeostasis and actions on mineralized tissues. The impact of estrogenic endocrine disrupting compounds on fish mineralized tissues will be reviewed, and the potential adverse outcomes of exposure to such compounds will be discussed. Current lacunae in knowledge are highlighted along with future research priorities. PMID:25196834

  15. Assessing water deprivation at the sub-river basin scale in LCA integrating downstream cascade effects.

    PubMed

    Loubet, Philippe; Roux, Philippe; Núñez, Montserrat; Belaud, Gilles; Bellon-Maurel, Véronique

    2013-12-17

    Physical water deprivation at the midpoint level is assessed in water-related LCIA methods using water scarcity indicators (e.g., withdrawal-to-availability and consumption-to-availability) at the river basin scale. Although these indicators represent a great step forward in the assessment of water-use-related impacts in LCA, significant challenges still remain in improving their accuracy and relevance. This paper presents a methodology that can be used to derive midpoint characterization factors for water deprivation taking into account downstream cascade effects within a single river basin. This effect is considered at a finer scale because a river basin must be split into different subunits. The proposed framework is based on a two-step approach. First, water scarcity is defined at the sub-river basin scale with the consumption-to-availability (CTA) ratio, and second, characterization factors for water deprivation (CFWD) are calculated, integrating the effects on downstream sub-river basins. The sub-river basin CTA and CFWD were computed based on runoff data, water consumption data and a water balance for two different river basins. The results show significant differences between the CFWD in a given river basin, depending on the upstream or downstream position. Finally, an illustrative example is presented, in which different land planning scenarios, taking into account additional water consumption in a city, are assessed. Our work demonstrates how crucial it is to localize the withdrawal and release positions within a river basin. PMID:24256030

  16. Herbivore diet breadth mediates the cascading effects of carnivores in food webs

    PubMed Central

    Singer, Michael S.; Lichter-Marck, Isaac H.; Farkas, Timothy E.; Aaron, Eric; Whitney, Kenneth D.; Mooney, Kailen A.

    2014-01-01

    Predicting the impact of carnivores on plants has challenged community and food web ecologists for decades. At the same time, the role of predators in the evolution of herbivore dietary specialization has been an unresolved issue in evolutionary ecology. Here, we integrate these perspectives by testing the role of herbivore diet breadth as a predictor of top-down effects of avian predators on herbivores and plants in a forest food web. Using experimental bird exclosures to study a complex community of trees, caterpillars, and birds, we found a robust positive association between caterpillar diet breadth (phylodiversity of host plants used) and the strength of bird predation across 41 caterpillar and eight tree species. Dietary specialization was associated with increased enemy-free space for both camouflaged (n = 33) and warningly signaled (n = 8) caterpillar species. Furthermore, dietary specialization was associated with increased crypsis (camouflaged species only) and more stereotyped resting poses (camouflaged and warningly signaled species), but was unrelated to caterpillar body size. These dynamics in turn cascaded down to plants: a metaanalysis (n = 15 tree species) showed the beneficial effect of birds on trees (i.e., reduced leaf damage) decreased with the proportion of dietary specialist taxa composing a tree species’ herbivore fauna. We conclude that herbivore diet breadth is a key functional trait underlying the trophic effects of carnivores on both herbivores and plants. PMID:24979778

  17. The effects of barrier disruption and moisturization on the dynamic drying mechanics of human stratum corneum.

    PubMed

    Liu, X; German, G K

    2015-09-01

    We study the dynamic drying mechanics of human stratum corneum, the most superficial layer of skin and essential physical and chemical barrier to the external environment. Barrier disruption caused by a depletion of lipids ordinarily found in healthy stratum corneum can occur with ageing, aggressive cleansing or with dry skin disorders and diseases such as atopic dermatitis and psoriasis. We establish the effects of severe barrier disruption on the dynamic drying mechanics of human stratum corneum by measuring variations in thickness and spatially resolved in-plane displacements in healthy and lipid depleted tissue samples drying in controlled environmental conditions. In-plane displacements recorded at regular intervals during drying are azimuthally averaged and fitted with a profile based on a linear elastic model. The measured thickness of the tissue sample is accounted for in each model fit. Dynamic variations in the drying stress and elastic modulus of the tissue are then established from the model fits. We find that barrier disruption causes dramatic reductions in drying timescales, increases in the elastic modulus of the tissue and larger drying stresses. We expect these changes to increase the propensity for cracking and chapping in skin. The maximum elastic modulus and drying stress of barrier disrupted stratum corneum (ESC=85.4±6.8 MPa, PSC=10.9±0.9 MPa) is reduced to levels comparable with stratum corneum containing lipids (ESC=26.1±3.2 MPa, PSC=2.58±0.45 MPa) after treatment with a 5% aqueous solution of glycerol. Neither 2% nor 5% glycerol solutions slow the accelerated drying timescales in barrier disrupted stratum corneum. PMID:26002418

  18. Cascaded automatic target recognition (Cascaded ATR)

    NASA Astrophysics Data System (ADS)

    Walls, Bradley

    2010-04-01

    The global war on terror has plunged US and coalition forces into a battle space requiring the continuous adaptation of tactics and technologies to cope with an elusive enemy. As a result, technologies that enhance the intelligence, surveillance, and reconnaissance (ISR) mission making the warfighter more effective are experiencing increased interest. In this paper we show how a new generation of smart cameras built around foveated sensing makes possible a powerful ISR technique termed Cascaded ATR. Foveated sensing is an innovative optical concept in which a single aperture captures two distinct fields of view. In Cascaded ATR, foveated sensing is used to provide a coarse resolution, persistent surveillance, wide field of view (WFOV) detector to accomplish detection level perception. At the same time, within the foveated sensor, these detection locations are passed as a cue to a steerable, high fidelity, narrow field of view (NFOV) detector to perform recognition level perception. Two new ISR mission scenarios, utilizing Cascaded ATR, are proposed.

  19. Environmental analysis of endocrine disrupting effects from hydrocarbon contaminants in the ecosystem. 1997 annual progress report

    SciTech Connect

    1997-01-01

    'The overall objective of the basic research grant is to characterize the potential of common hydrocarbon contaminants in ecosystems to act as endocrine disruptors. The three major lines of research include (1) a biotechnology based screening system to identify potential hormone mimics and antagonists; (2) an animal screening system to identify biomarkers of endocrine effects. and (3) a literature review to identify compounds at a variety of DOE sites that need to be examined for endocrine disrupting effects. By relating results obtained from this research project to contamination problems at various DOE sites. CBR will provide data and information on endocrine disrupting contaminants to DOE for consideration in risk analyses for determining clean-up levels and priorities needed at the sites.'

  20. The nitrogen cascade

    SciTech Connect

    Galloway J.N.; Aber J.D.; Erisman J.W.; Seitzinger S.P.; Howarth R.W.; Cowling E.B.; Cosby B.J.

    2003-04-01

    Human production of food and energy is the dominant continental process that breaks the triple bond in molecular nitrogen (N{sub 2}) and creates reactive nitrogen (Nr) species. Circulation of anthropogenic Nr in Earth's atmosphere, hydrosphere, and biosphere has a wide variety of consequences, which are magnified with time as Nr moves along its biogeochemical pathway. The same atom of Nr can cause multiple effects in the atmosphere, in terrestrial ecosystems, in freshwater and marine systems, and on human health. We call this sequence of effects the nitrogen cascade. As the cascade progresses, the origin of Nr becomes unimportant. Reactive nitrogen does not cascade at the same rate through all environmental systems; some systems have the ability to accumulate Nr, which leads to lag times in the continuation of the cascade. These lags slow the cascade and result in Nr accumulation in certain reservoirs, which in turn can enhance the effects of Nr on that environment. The only way to eliminate Nr accumulation and stop the cascade is to convert Nr back to nonreactive N{sub 2}.

  1. Cascading ecological effects of low-level phosphorus enrichment in the Florida Everglades

    USGS Publications Warehouse

    Gaiser, E.E.; Trexler, J.C.; Richards, J.H.; Childers, D.L.; Lee, D.; Edwards, A.L.; Scinto, L.J.; Jayachandran, K.; Noe, G.B.; Jones, R.D.

    2005-01-01

    Few studies have examined long-term ecological effects of sustained low-level nutrient enhancement on wetland biota. To determine sustained effects of phosphorus (P) addition on Everglades marshes we added P at low levels (5, 15, and 30 ??g L-1 above ambient) for 5 yr to triplicate 100-m flow-through channels in pristine marsh. A cascade of ecological responses occurred in similar sequence among treatments. Although the rate of change increased with dosing level, treatments converged to similar enriched endpoints, characterized most notably by a doubling of plant biomass and elimination of native, calcareous periphyton mats. The full sequence of biological changes occurred without an increase in water total P concentration, which remained near ambient levels until Year 5. This study indicates that Everglades marshes have a near-zero assimilative capacity for P without a state change, that ecosystem responses to enrichment accumulate over time, and that downstream P transport mainly occurs through biota rather than the water column.

  2. Nonlinear effects in collision cascades and high energy shock waves during ta-C:H growth

    SciTech Connect

    Piazza, F.; Resto, O.; Morell, G.

    2007-07-01

    The surface topography of hydrogenated tetrahedral amorphous carbon (ta-C:H) is critical for various applications such as microelectromechanical devices, magnetic and optical storage devices, and medical implants. The surface topography of ta-C:H films deposited by distributed electron cyclotron resonance plasma from C{sub 2}H{sub 2} gas precursor was investigated. The effects of pressure, together with ion flux and energy, are studied by atomic force microscopy in relation to the structural evolution of the films. The results are compared with the predictions of the Edward-Wilkinson model [Proc. R. Soc. London, Ser. A 44, 1039 (1966)] recently proposed to account for ta-C:H growth and with previous interpretations based on hypersonic shock waves. The random hillocks observed on the smooth surfaces of ta-C:H films deposited at high pressure are thought to result from the interference of high energy shock waves triggered by C{sub 4}H{sub x}{sup +} ions that produce overlapping collision cascades and induce nonlinear effects.

  3. Interrelated effects of mycorrhiza and free-living nitrogen fixers cascade up to aboveground herbivores

    PubMed Central

    Khaitov, Botir; Patiño-Ruiz, José David; Pina, Tatiana; Schausberger, Peter

    2015-01-01

    Aboveground plant performance is strongly influenced by belowground microorganisms, some of which are pathogenic and have negative effects, while others, such as nitrogen-fixing bacteria and arbuscular mycorrhizal fungi, usually have positive effects. Recent research revealed that belowground interactions between plants and functionally distinct groups of microorganisms cascade up to aboveground plant associates such as herbivores and their natural enemies. However, while functionally distinct belowground microorganisms commonly co-occur in the rhizosphere, their combined effects, and relative contributions, respectively, on performance of aboveground plant-associated organisms are virtually unexplored. Here, we scrutinized and disentangled the effects of free-living nitrogen-fixing (diazotrophic) bacteria Azotobacter chroococcum (DB) and arbuscular mycorrhizal fungi Glomus mosseae (AMF) on host plant choice and reproduction of the herbivorous two-spotted spider mite Tetranychus urticae on common bean plants Phaseolus vulgaris. Additionally, we assessed plant growth, and AMF and DB occurrence and density as affected by each other. Both AMF alone and DB alone increased spider mite reproduction to similar levels, as compared to the control, and exerted additive effects under co-occurrence. These effects were similarly apparent in host plant choice, that is, the mites preferred leaves from plants with both AMF and DB to plants with AMF or DB to plants grown without AMF and DB. DB, which also act as AMF helper bacteria, enhanced root colonization by AMF, whereas AMF did not affect DB abundance. AMF but not DB increased growth of reproductive plant tissue and seed production, respectively. Both AMF and DB increased the biomass of vegetative aboveground plant tissue. Our study breaks new ground in multitrophic belowground–aboveground research by providing first insights into the fitness implications of plant-mediated interactions between interrelated belowground fungi

  4. [Transthyretin-binding activity of hexabromocyclododecanes (HBCDs) and its thyroid hormone disrupting effects after developmental exposure].

    PubMed

    Ji, Xiu-Ling; Liu, Yang; Liu, Fang; Lu, Yue; Zhong, Gao-Ren

    2010-09-01

    In vivo and in vitro research approaches were carried out to survey the potential health risk of environmental exposure by hexabromocyclododecanes (HBCDs). Transthyretin-binding assay was designed to test for the potency of HBCDs to compete with thyroxine (T4) for binding to the transport protein. The results showed that the binding of 25I-T4 and T4 was only slightly inhabited even at the highest competitive concentration of HBCDs (75.08%, 80 micromol x L(-1)), indicating the marginally interfere potency of HBCDs in the transportation of T4. Sprague-Dawley rats of 3-days old were exposed to 0.2 mg/kg and 1 mg/kg HBCDs for 21 d to examine the thyroid hormones (THs) disrupting effects of HBCDs after developmental exposure. Compared with the controls, levels of total 3,3',5-triiodothyronine (TT3), free 3,3',5-triiodothyronine (FT3), increased significantly (p < 0.05, p < 0.05) in low- and high-dose exposures, thyroid stimulating hormone (TSH) also increased slightly while the total thyroxine (TT4), free thyroxine (FT4) had a decline about two-fold inversely. Combined both the in vivo and in vitro results, the possible mode of action of HBCDs on THs disruption may through the synergy or substitution effect of T3. The findings support further investigation of the potential THs disrupting effects of HBCDs on public health, especially on children during brain development. PMID:21072945

  5. Combined adverse effects of cascading events on systems' functionality: an insular case study, French West Indies

    NASA Astrophysics Data System (ADS)

    Desramaut, Nicolas; Wang, Justin; Gehl, Pierre; Marti, Jose; Baills, Audrey; Reveillere, Arnaud

    2013-04-01

    In our modern societies, lifelines play a vital role, even in normal conditions. Therefore, during crises, the dependency to critical infrastructures is likely to be exacerbated. Indeed, in order to provide quick emergency services to the population, systems have to be functional. However, even if not directly damaged, in order to be functional, elements of the different systems have to receive enough resources but also to be able to supply their own services. In a multi-risk approach, this necessity to take into account systemic vulnerability to assess the real impact of natural hazards on society is even made more obvious. For example, impacts of one hazard, taken separately, might not significantly affect societies, but might reduce redundancy, and therefore could increase functional vulnerability to other hazards. The present study aims at analyzing the effects of cascading events on the behaviour of interdependent systems and on the capacities of the health care system to treat the victims. In order to work on a close system, an insular context (Guadeloupe, French West Indies) has been selected. The hazard cascading scenario consists of a M6.3 earthquake striking Basse-Terre, and triggering landslides in the mountainous areas where antecedent precipitations have made the area prone to slide. Damages due to earthquakes have been estimated for the 5 considered systems (buildings, healthcare system, electrical network, water supply network and transportation). Due to their localization in mountainous areas, landslides would affect only transportation networks, with closure of roads. The inter- and intra-dependencies of systems have been modeled thanks to the I2Sim platform developed at UBC. The functionality of each element is therefore the consequence of the physical (direct damage) but also functional (indirect) damage. Analyses are performed for different strategies of resources allocations, and one of the final results is the impact of the induced landslides

  6. Cascading Proximity Effect and Singlet-Triplet Mixing in Rotating Magnetization Junctions

    NASA Astrophysics Data System (ADS)

    Bill, Andreas; Baker, Thomas E.; Richie-Halford, Adam

    2015-03-01

    The proximity of a superconductor to an inhomogeneous magnetic material induces singlet and triplet pair correlations in the hybrid structure. The amount of each component and their presence deep in the magnetic material strongly depends on the magnetic inhomogeneity. We present a comparative study of pair correlations in a diffusive magnetic Josephson junction involving a multilayer with misaligned magnetization, a cosine-type helical structure and a more flexible and realistic domain wall of an exchange spring. Using the cascading effect we demonstrate that the three systems induce qualitatively different mixtures of correlations. In particular, we show that misaligned and continuously rotating magnetizations do not display the same physical state. Analyzing the Gor'kov functions we find that so-called short range singlet correlations can be found deep in the magnetic material and compete with triplet correlations giving rise to the so-called singlet-triplet 0 - π transition. We gratefully acknowledge support from the National Science Foundation (DMR-1309341). TEB graciously thanks the support of the UC Irvine Achievement Rewards for College Scientists Fellowship.

  7. The Influence of Plasma Effects of Pair Beams on the Intergalactic Cascade Emission of Blazars

    NASA Astrophysics Data System (ADS)

    Menzler, Ulf; Schlickeiser, Reinhard

    2014-03-01

    The attenuation of TeV γ-rays from distant blazars by the extragalactic background light (EBL) produces relativistic electron-positron pair beams. It has been shown by Broderick et. al. (2012) and Schlickeiser et. al (2012) that a pair beam traversing the intergalactic medium is unstable to linear two-stream instabilities of both electrostatic and electromagnetic nature. While for strong blazars all free pair energy is dissipated in heating the intergalactic medium and a potential electromagnetic cascade via inverse-Compton scattering with the cosmic microwave background is suppressed, we investigate the case of weak blazars where the back reaction of generated electrostatic turbulence leads to a plateauing of the electron energy spectrum. In the ultra-relativistic Thomson limit we analytically calculate the inverse-Compton spectral energy distribution for both an unplateaued and a plateaued beam scenario, showing a peak reduction factor of Rpeak ≈ 0.345. This is consistent with the FERMI non-measurements of a GeV excess in the spectrum of EBL attenuated TeV blazars. Claims on the lower bound of the intergalactic magnetic field strengths, made by several authors neglecting plasma effects, are thus put into question.

  8. Electron Acceleration by Cascading Reconnection in the Solar Corona. I. Magnetic Gradient and Curvature Drift Effects

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Büchner, J.; Bárta, M.; Gan, W.; Liu, S.

    2015-12-01

    We investigate the electron acceleration by magnetic gradient and curvature drift effects in cascading magnetic reconnection of a coronal current sheet via a test particle method in the framework of the guiding center approximation. After several Alfvén transit times, most of the electrons injected at the current sheet are still trapped in the magnetic islands. A small fraction of the injected electrons precipitate into the chromosphere. The acceleration of trapped electrons is dominated by the magnetic curvature drifts, which change the parallel momentum of the electron, and appears to be more efficient than the acceleration of precipitating electrons, which is dominated by the perpendicular momentum change caused by the magnetic gradient drifts. With the resulting trapped energetic electron distribution, the corresponding hard X-ray (HXR) radiation spectra are calculated using an optically thin Bremsstrahlung model. Trapped electrons may explain flare loop top HXR emission as well as the observed bright spots along current sheets trailing coronal mass ejections. The asymmetry of precipitating electrons with respect to the polarity inversion line may contribute to the observed asymmetry of footpoint emission.

  9. Attachment security and pain--The disrupting effect of captivity and PTSS.

    PubMed

    Andersen, Tonny Elmose; Lahav, Yael; Defrin, Ruth; Mikulincer, Mario; Solomon, Zahava

    2015-12-01

    The present study assesses the possible disruption effect of posttraumatic stress symptoms (PTSS) with regard to the protective role of attachment on pain, among ex-POWs. While secure attachment seems to serve as a buffer, decreasing the perception of pain, this function may be disrupted by PTSS. The study sample included 104 subjects who were combat veterans of the 1973 Yom Kippur War comprising of 60 male ex-prisoners of war (ex-POWs) and 44 comparable male combat veterans. Both attachment and pain were investigated experimentally in the laboratory and via questionnaires. We found that ex-POWs showed higher levels of clinical pain and attachment insecurities compared to controls. Moreover, attachment avoidance and soothing effect of attachment (SEA) were both associated with lower levels of clinical pain. Most importantly, PTSS moderated the associations between attachment and pain, as well as the mediation role of attachment between captivity and pain. The results imply that although attachment can be an important resource for coping with pain, it can be severely disrupted by PTSS among trauma survivors. PMID:26652590

  10. Cascading effects of induced terrestrial plant defences on aquatic and terrestrial ecosystem function.

    PubMed

    Jackrel, Sara L; Wootton, J Timothy

    2015-04-22

    Herbivores induce plants to undergo diverse processes that minimize costs to the plant, such as producing defences to deter herbivory or reallocating limited resources to inaccessible portions of the plant. Yet most plant tissue is consumed by decomposers, not herbivores, and these defensive processes aimed to deter herbivores may alter plant tissue even after detachment from the plant. All consumers value nutrients, but plants also require these nutrients for primary functions and defensive processes. We experimentally simulated herbivory with and without nutrient additions on red alder (Alnus rubra), which supplies the majority of leaf litter for many rivers in western North America. Simulated herbivory induced a defence response with cascading effects: terrestrial herbivores and aquatic decomposers fed less on leaves from stressed trees. This effect was context dependent: leaves from fertilized-only trees decomposed most rapidly while leaves from fertilized trees receiving the herbivory treatment decomposed least, suggesting plants funnelled a nutritionally valuable resource into enhanced defence. One component of the defence response was a decrease in leaf nitrogen leading to elevated carbon : nitrogen. Aquatic decomposers prefer leaves naturally low in C : N and this altered nutrient profile largely explains the lower rate of aquatic decomposition. Furthermore, terrestrial soil decomposers were unaffected by either treatment but did show a preference for local and nitrogen-rich leaves. Our study illustrates the ecological implications of terrestrial herbivory and these findings demonstrate that the effects of selection caused by terrestrial herbivory in one ecosystem can indirectly shape the structure of other ecosystems through ecological fluxes across boundaries. PMID:25788602

  11. Cascading effects of induced terrestrial plant defences on aquatic and terrestrial ecosystem function

    PubMed Central

    Jackrel, Sara L.; Wootton, J. Timothy

    2015-01-01

    Herbivores induce plants to undergo diverse processes that minimize costs to the plant, such as producing defences to deter herbivory or reallocating limited resources to inaccessible portions of the plant. Yet most plant tissue is consumed by decomposers, not herbivores, and these defensive processes aimed to deter herbivores may alter plant tissue even after detachment from the plant. All consumers value nutrients, but plants also require these nutrients for primary functions and defensive processes. We experimentally simulated herbivory with and without nutrient additions on red alder (Alnus rubra), which supplies the majority of leaf litter for many rivers in western North America. Simulated herbivory induced a defence response with cascading effects: terrestrial herbivores and aquatic decomposers fed less on leaves from stressed trees. This effect was context dependent: leaves from fertilized-only trees decomposed most rapidly while leaves from fertilized trees receiving the herbivory treatment decomposed least, suggesting plants funnelled a nutritionally valuable resource into enhanced defence. One component of the defence response was a decrease in leaf nitrogen leading to elevated carbon : nitrogen. Aquatic decomposers prefer leaves naturally low in C : N and this altered nutrient profile largely explains the lower rate of aquatic decomposition. Furthermore, terrestrial soil decomposers were unaffected by either treatment but did show a preference for local and nitrogen-rich leaves. Our study illustrates the ecological implications of terrestrial herbivory and these findings demonstrate that the effects of selection caused by terrestrial herbivory in one ecosystem can indirectly shape the structure of other ecosystems through ecological fluxes across boundaries. PMID:25788602

  12. Cascading effects of belowground predators on plant communities are density-dependent.

    PubMed

    Thakur, Madhav Prakash; Herrmann, Martina; Steinauer, Katja; Rennoch, Saskia; Cesarz, Simone; Eisenhauer, Nico

    2015-10-01

    interspecific plant competition. These results highlight that belowground predators can relax interspecific plant competition by increasing nutrient mineralization through their density-dependent cascading effects on detritivore and soil microbial communities. PMID:26664680

  13. Flow range enhancement by secondary flow effect in low solidity circular cascade diffusers

    NASA Astrophysics Data System (ADS)

    Sakaguchi, Daisaku; Tun, Min Thaw; Mizokoshi, Kanata; Kishikawa, Daiki

    2014-08-01

    High-pressure ratio and wide operating range are highly required for compressors and blowers. The technical issue of the design is achievement of suppression of flow separation at small flow rate without deteriorating the efficiency at design flow rate. A numerical simulation is very effective in design procedure, however, cost of the numerical simulation is generally high during the practical design process, and it is difficult to confirm the optimal design which is combined with many parameters. A multi-objective optimization technique is the idea that has been proposed for solving the problem in practical design process. In this study, a Low Solidity circular cascade Diffuser (LSD) in a centrifugal blower is successfully designed by means of multi-objective optimization technique. An optimization code with a meta-model assisted evolutionary algorithm is used with a commercial CFD code ANSYS-CFX. The optimization is aiming at improving the static pressure coefficient at design point and at low flow rate condition while constraining the slope of the lift coefficient curve. Moreover, a small tip clearance of the LSD blade was applied in order to activate and to stabilize the secondary flow effect at small flow rate condition. The optimized LSD blade has an extended operating range of 114 % towards smaller flow rate as compared to the baseline design without deteriorating the diffuser pressure recovery at design point. The diffuser pressure rise and operating flow range of the optimized LSD blade are experimentally verified by overall performance test. The detailed flow in the diffuser is also confirmed by means of a Particle Image Velocimeter. Secondary flow is clearly captured by PIV and it spreads to the whole area of LSD blade pitch. It is found that the optimized LSD blade shows good improvement of the blade loading in the whole operating range, while at small flow rate the flow separation on the LSD blade has been successfully suppressed by the secondary flow

  14. Effects of Morphine on Temporal Discrimination and Color Matching: General Disruption of Stimulus Control or Selective Effects on Timing?

    ERIC Educational Resources Information Center

    Ward, Ryan D.; Odum, Amy L.

    2005-01-01

    Discrepant effects of drugs on behavior maintained by temporal-discrimination procedures make conclusive statements about the neuropharmacological bases of timing difficult. The current experiment examined the possible contribution of a general, drug-induced disruption of stimulus control. Four pigeons responded on a three-component multiple…

  15. Differential Effects of Wildfire and Forest Harvest on Snow Hydrology in the Oregon Cascades

    NASA Astrophysics Data System (ADS)

    Nolin, A. W.; Gleason, K. E.; Roth, T.; Cooper, M. G.

    2014-12-01

    Snow hydrology, climate, and forest ecosystems are intricately connected, with snow serving as a key moisture source for forests while forests fundamentally affect snow accumulation and ablation. These connections have important implications for western US water resources and forest management. Forests reduce snow accumulation via canopy interception while ablation is affected via changes in energy balance. We contrast the snow hydrology of undisturbed forests in the Oregon Cascades with those affected by wildfire and forest harvest. When the forest canopy is removed by wildfire or forest harvest it increases total snow accumulation and increases snowmelt rates. After a high-severity wildfire, canopy removal increases light transmission to the snow. The charred standing trees shed burned debris onto the snowpack surface decreasing snow albedo. The net result for the snowpack is much higher absorbed shortwave radiation and earlier/faster melt. Our work shows that the albedo effect can persist for several years after the fire. Forest harvest also reduces the forest canopy but unlike the post-wildfire environment, forest litter decreases. Our measurements and modeling results show that the effects of forest harvest on snow vary with elevation. At our lower-elevation warmer sites, snow persists longer in the open areas than in the forest while at the higher elevation colder sites, snow persists longer in the forest. In addition to our snow hydrology results, we present preliminary hydrologic modeling showing how these differences in snow accumulation and melt rates influence streamflow in watersheds dominated by surface runoff and in those dominated by groundwater flow.

  16. Effect of Calcium on the Oxidative Phosphorylation Cascade in Skeletal Muscle Mitochondria

    PubMed Central

    Glancy, Brian; Willis, Wayne T; Chess, David J; Balaban, Robert S

    2014-01-01

    Calcium is believed to regulate mitochondrial oxidative phosphorylation, thereby contributing to the maintenance of cellular energy homeostasis. Skeletal muscle, with an energy conversion dynamic range of up to 100-fold, is an extreme case for evaluating the cellular balance of ATP production and consumption. This study examined the role of Ca2+ on the entire oxidative phosphorylation reaction network in isolated skeletal muscle mitochondria and attempted to extrapolate these results back to the muscle, in vivo. Kinetic analysis was conducted to evaluate the dose response effect of Ca2+ on the maximum velocity of oxidative phosphorylation (VmaxO) and the ADP affinity. Force-flow analysis evaluated the interplay between energetic driving forces and flux to determine the conductance, or effective activity, of individual steps within oxidative phosphorylation. Measured driving forces (extramitochondrial phosphorylation potential (ΔGATP), membrane potential, and redox states of NADH and cytochromes bH, bL, c1, c, and a,a3) were compared with flux (oxygen consumption) at 37°C. 840 nM Ca2+ generated a ∼2 fold increase in VmaxO with no change in ADP affinity (∼43 μM). Force-flow analysis revealed that Ca2+ activation of VmaxO was distributed throughout the oxidative phosphorylation reaction sequence. Specifically, Ca2+ increased the conductance of Complex IV (2.3-fold), Complexes I+III (2.2-fold), ATP production/transport (2.4-fold), and fuel transport/dehydrogenases (1.7-fold). These data support the notion that Ca2+ activates the entire muscle oxidative phosphorylation cascade, while extrapolation of these data to the exercising muscle predicts a significant role of Ca2+ in maintaining cellular energy homeostasis. PMID:23547908

  17. Tracking Earthquake Cascades

    NASA Astrophysics Data System (ADS)

    Jordan, T. H.

    2011-12-01

    In assessing their risk to society, earthquakes are best characterized as cascades that can propagate from the natural environment into the socio-economic (built) environment. Strong earthquakes rarely occur as isolated events; they usually cluster in foreshock-mainshock-aftershock sequences, seismic swarms, and extended sequences of large earthquakes that propagate along major fault systems. These cascades are regulated by stress-mediated interactions among faults driven by tectonic loading. Within these cascades, each large event can itself cause a chain reaction in which the primary effects of faulting and ground shaking induce secondary effects, including tsunami, landslides, liquefaction, and set off destructive processes within the built environment, such as fires and radiation leakage from nuclear plants. Recent earthquakes have demonstrated how the socio-economic effects of large earthquakes can reverberate for many years. To reduce earthquake risk and improve the resiliency of communities to earthquake damage, society depends on five geotechnologies for tracking earthquake cascades: long-term probabilistic seismic hazard analysis (PSHA), short-term (operational) earthquake forecasting, earthquake early warning, tsunami warning, and the rapid production of post-event information for response and recovery (see figure). In this presentation, I describe how recent advances in earthquake system science are leading to improvements in this geotechnology pipeline. In particular, I will highlight the role of earthquake simulations in predicting strong ground motions and their secondary effects before and during earthquake cascades

  18. Cascading effects of fire retardant on plant-microbe interactions, community composition, and invasion.

    PubMed

    Marshall, Abigail; Waller, Lauren; Lekberg, Ylva

    2016-06-01

    Climate change, historical fire suppression, and a rise in human movements in urban-forest boundaries have resulted in an increased use of long-term fire retardant (LTFR). While LTFR is an effective fire-fighting tool, it contains high concentrations of nitrogen and phosphorus, and little is known about how this nutrient pulse affects terrestrial ecosystems. We used field surveys and greenhouse experiments to quantify effects of LTFR on plant productivity, community composition, and plant interactions with the ubiquitous root symbiont arbuscular mycorrhizal fungi (AMF). In the field, LTFR applications were associated with persistent shifts in plant communities toward exotic annuals with little or no dependency of AMF. Plants exposed to LTFR were less colonized by AMF, both in field surveys and in the greenhouse, and this was most likely due to the substantial and persistent increase in soil available phosphorus. All plants grew bigger with LTFR in the greenhouse, but the invasive annual cheatgrass (Bromus tectorum) benefitted most. While LTFR can control fires, it may cause long-term changes in soil nutrient availabilities, disrupt plant interactions with beneficial soil microbes, and exasperate invasion by some exotic plants. PMID:27509743

  19. CFD study on the effects of viscous shear in a hot cascade Ranque-Hilsch vortex tube

    NASA Astrophysics Data System (ADS)

    Bej, Nilotpala; Sinhamahapatra, K. P.

    2015-12-01

    The objective of this paper is to carry out an extensive Computational Fluid Dynamics (CFD) study on work transfer due to viscous shear in a hot cascade Ranque-Hilsch vortex tube. The commercial CFD code ANSYS FLUENT 14.0 has been employed to carry out the numerical analysis using RANS standard k-epsilon turbulence model. A two-dimensional axisymmetric geometrical domain has been generated with structured mesh and air has been taken as the working fluid. The CFD results reveal that work transfer due to the action of viscous shear along the tangential direction increases considerably with hot cascading. However, the work transfer due to viscous shear along the axial direction degrades the performance of the device as the heat transfer takes place from cold zone to the hot zone. The effect of radial shear stress is negligible due to low value of radial velocity gradient.

  20. Unintended consequences of management actions in salt pond restoration: cascading effects in trophic interactions

    USGS Publications Warehouse

    Takekawa, John Y.; Ackerman, Joshua T.; Brand, Arriana; Graham, Tanya R.; Eagles-Smith, Collin A.; Herzog, Mark; Topping, Brent R.; Shellenbarger, Gregory; Kuwabara, James S.; Mruz, Eric; Piotter, Sara L.; Athearn, Nicole D.

    2015-01-01

    Salt evaporation ponds have played an important role as habitat for migratory waterbirds across the world, however, efforts to restore and manage these habitats to maximize their conservation value has proven to be challenging. For example, salinity reduction has been a goal for restoring and managing former salt evaporation ponds to support waterbirds in the South Bay Salt Pond Restoration Project in San Francisco Bay, California, USA. Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO) event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations. We document the ramifications of an anoxic event in water quality including salinity, DO, and temperature, and in the response of the biota including prey fish biomass, numerical response by California Gulls (Larus californicus), and chick survival of Forster's Tern (Sterna forsteri). Management actions intended to protect receiving waters resulted in decreased DO concentrations that collapsed to zero for ≥ 4 consecutive days, resulting in an extensive fish kill. DO depletion likely resulted from an algal bloom that arose following transition of the pond system from high to low salinity as respiration and decomposition outpaced photosynthetic production. We measured a ≥ 6-fold increase in biomass of fish dropped on the levee by foraging avian predators compared with weeks prior to and following the low-DO event. California Gulls rapidly responded to the availability of aerobically-stressed and vulnerable fish and increased in abundance by two orders of magnitude. Mark-recapture analysis of 254 Forster's Tern chicks indicated that their survival declined substantially following the increase in gull abundance. Thus, management actions to reduce salinity concentrations resulted in cascading effects in trophic interactions that serves as a cautionary tale illustrating the importance of understanding the interaction of water quality

  1. Unintended Consequences of Management Actions in Salt Pond Restoration: Cascading Effects in Trophic Interactions

    PubMed Central

    Takekawa, John Y.; Ackerman, Joshua T.; Brand, L. Arriana; Graham, Tanya R.; Eagles-Smith, Collin A.; Herzog, Mark P.; Topping, Brent R.; Shellenbarger, Gregory G.; Kuwabara, James S.; Mruz, Eric; Piotter, Sara L.; Athearn, Nicole D.

    2015-01-01

    Salt evaporation ponds have played an important role as habitat for migratory waterbirds across the world, however, efforts to restore and manage these habitats to maximize their conservation value has proven to be challenging. For example, salinity reduction has been a goal for restoring and managing former salt evaporation ponds to support waterbirds in the South Bay Salt Pond Restoration Project in San Francisco Bay, California, USA. Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO) event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations. We document the ramifications of an anoxic event in water quality including salinity, DO, and temperature, and in the response of the biota including prey fish biomass, numerical response by California Gulls (Larus californicus), and chick survival of Forster's Tern (Sterna forsteri). Management actions intended to protect receiving waters resulted in decreased DO concentrations that collapsed to zero for ≥ 4 consecutive days, resulting in an extensive fish kill. DO depletion likely resulted from an algal bloom that arose following transition of the pond system from high to low salinity as respiration and decomposition outpaced photosynthetic production. We measured a ≥ 6-fold increase in biomass of fish dropped on the levee by foraging avian predators compared with weeks prior to and following the low-DO event. California Gulls rapidly responded to the availability of aerobically-stressed and vulnerable fish and increased in abundance by two orders of magnitude. Mark-recapture analysis of 254 Forster's Tern chicks indicated that their survival declined substantially following the increase in gull abundance. Thus, management actions to reduce salinity concentrations resulted in cascading effects in trophic interactions that serves as a cautionary tale illustrating the importance of understanding the interaction of water quality

  2. Unintended consequences of management actions in salt pond restoration: cascading effects in trophic interactions.

    PubMed

    Takekawa, John Y; Ackerman, Joshua T; Brand, L Arriana; Graham, Tanya R; Eagles-Smith, Collin A; Herzog, Mark P; Topping, Brent R; Shellenbarger, Gregory G; Kuwabara, James S; Mruz, Eric; Piotter, Sara L; Athearn, Nicole D

    2015-01-01

    Salt evaporation ponds have played an important role as habitat for migratory waterbirds across the world, however, efforts to restore and manage these habitats to maximize their conservation value has proven to be challenging. For example, salinity reduction has been a goal for restoring and managing former salt evaporation ponds to support waterbirds in the South Bay Salt Pond Restoration Project in San Francisco Bay, California, USA. Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO) event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations. We document the ramifications of an anoxic event in water quality including salinity, DO, and temperature, and in the response of the biota including prey fish biomass, numerical response by California Gulls (Larus californicus), and chick survival of Forster's Tern (Sterna forsteri). Management actions intended to protect receiving waters resulted in decreased DO concentrations that collapsed to zero for ≥ 4 consecutive days, resulting in an extensive fish kill. DO depletion likely resulted from an algal bloom that arose following transition of the pond system from high to low salinity as respiration and decomposition outpaced photosynthetic production. We measured a ≥ 6-fold increase in biomass of fish dropped on the levee by foraging avian predators compared with weeks prior to and following the low-DO event. California Gulls rapidly responded to the availability of aerobically-stressed and vulnerable fish and increased in abundance by two orders of magnitude. Mark-recapture analysis of 254 Forster's Tern chicks indicated that their survival declined substantially following the increase in gull abundance. Thus, management actions to reduce salinity concentrations resulted in cascading effects in trophic interactions that serves as a cautionary tale illustrating the importance of understanding the interaction of water quality

  3. The Effect of Disruption of Prefrontal Cortical Function with Transcranial Magnetic Stimulation on Visual Working Memory

    PubMed Central

    Lorenc, Elizabeth S.; Lee, Taraz G.; Chen, Anthony J.-W.; D’Esposito, Mark

    2015-01-01

    It is proposed that feedback signals from the prefrontal cortex (PFC) to extrastriate cortex are essential for goal-directed processing, maintenance, and selection of information in visual working memory (VWM). In a previous study, we found that disruption of PFC function with transcranial magnetic stimulation (TMS) in healthy individuals impaired behavioral performance on a face/scene matching task and decreased category-specific tuning in extrastriate cortex as measured with functional magnetic resonance imaging (fMRI). In this study, we investigated the effect of disruption of left inferior frontal gyrus (IFG) function on the fidelity of neural representations of two distinct information codes: (1) the stimulus category and (2) the goal-relevance of viewed stimuli. During fMRI scanning, subjects were presented face and scene images in pseudo-random order and instructed to remember either faces or scenes. Within both anatomical and functional regions of interest (ROIs), a multi-voxel pattern classifier was used to quantitatively assess the fidelity of activity patterns representing stimulus category: whether a face or a scene was presented on each trial, and goal relevance, whether the presented image was task relevant (i.e., a face is relevant in a “Remember Faces” block, but irrelevant in a “Remember Scenes” block). We found a reduction in the fidelity of the stimulus category code in visual cortex after left IFG disruption, providing causal evidence that lateral PFC modulates object category codes in visual cortex during VWM. In addition, we found that IFG disruption caused a reduction in the fidelity of the goal relevance code in a distributed set of brain regions. These results suggest that the IFG is involved in determining the task-relevance of visual input and communicating that information to a network of regions involved in further processing during VWM. Finally, we found that participants who exhibited greater fidelity of the goal relevance

  4. Integration of nanoassembly functions for an effective delivery cascade for cancer drugs.

    PubMed

    Sun, Qihang; Sun, Xuanrong; Ma, Xinpeng; Zhou, Zhuxian; Jin, Erlei; Zhang, Bo; Shen, Youqing; Van Kirk, Edward A; Murdoch, William J; Lott, Joseph R; Lodge, Timothy P; Radosz, Maciej; Zhao, Yuliang

    2014-12-01

    A "cluster-bomb"-like lipid-dendrimer nanoassembly synergizes the functions of its components and thereby efficiently accomplishes the drug delivery cascade for high efficacy in treating cancer. The nanoassembly successfully circulates in the blood and accumulates in the tumor. Once in the tumor, it releases small dendrimers that act like "bomblets", enabling tumor penetration, cell internalization, and drug release. PMID:25328159

  5. Effect of winglet geometry arrangement and incidence on tip clearance control in a compressor cascade

    NASA Astrophysics Data System (ADS)

    Han, Shaobing; Zhong, Jingjun; Lu, Huawei; Kan, Xiaoxu; Yang, Ling

    2014-08-01

    An experimental study is conducted to investigate the influences of blade tip winglet on the flow field of a compressor cascade. The tests are performed in a low speed linear cascade with stationary endwall, with three blade tip configurations, including the baseline tip, the suction-side winglet tip and the pressure-side winglet tip. The flowfield downstream of the cascade is measured using five-hole probe, from which the three-dimensional velocity field, vorticity field and pressure field are obtained. Static pressure measurements are made on the endwall above the blade row using pressure taps embedded in the plywood endwall. All measurements are made at both design and off-design conditions for tip clearance level of about 2 percent of the blade chord. The results revealed the incidence variation significantly affects the secondary flow and the associated loss field downstream of the cascade, where the tip leakage vortex and passage vortex exist as the major contributors on the field. The winglet geometry arrangements can change the trajectory of the tip leakage vortex. The suction-side winglet tip blade provides a lower overall total pressure loss coefficient when compared to the baseline tip blade and pressure-side winglet tip blade at all incidence angles.

  6. Late-life effects on rat reproductive system after developmental exposure to mixtures of endocrine disrupters.

    PubMed

    Isling, Louise Krag; Boberg, Julie; Jacobsen, Pernille Rosenskjold; Mandrup, Karen Riiber; Axelstad, Marta; Christiansen, Sofie; Vinggaard, Anne Marie; Taxvig, Camilla; Kortenkamp, Andreas; Hass, Ulla

    2014-01-01

    This study examined late-life effects of perinatal exposure of rats to a mixture of endocrine-disrupting contaminants. Four groups of 14 time-mated Wistar rats were exposed by gavage from gestation day 7 to pup day 22 to a mixture of 13 anti-androgenic and estrogenic chemicals including phthalates, pesticides, u.v.-filters, bisphenol A, parabens, and the drug paracetamol. The groups received vehicle (control), a mixture of all 13 chemicals at 150-times (TotalMix150) or 450-times (TotalMix450) high-end human exposure, or 450-times a mixture of nine predominantly anti-androgenic chemicals (AAMix450). Onset of puberty and estrous cyclicity at 9 and 12 months of age were assessed. Few female offspring showed significantly regular estrus cyclicity at 12 months of age in the TotalMix450 and AAMix450 groups compared with controls. In 19-month-old male offspring, epididymal sperm counts were lower than controls, and in ventral prostate an overrepresentation of findings related to hyperplasia was observed in exposed groups compared with controls, particularly in the group dosed with anti-androgens. A higher incidence of pituitary adenoma at 19 months of age was found in males and females in the AAMix450 group. Developmental exposure of rats to the highest dose of a human-relevant mixture of endocrine disrupters induced adverse effects late in life, manifested as earlier female reproductive senescence, reduced sperm counts, higher score for prostate atypical hyperplasia, and higher incidence of pituitary tumors. These delayed effects highlight the need for further studies on the role of endocrine disrupters in hormone-related disorders in aging humans. PMID:24287426

  7. Semihydrophobic nanoparticle-induced disruption of supported lipid bilayers: specific ion effect.

    PubMed

    Jing, Benxin; Abot, Rosary C T; Zhu, Yingxi

    2014-11-20

    The interaction of nanoparticles with cell membranes is critical to understand and control the structural change and molecular transport of cell membranes for medicines and medical diagnostics, in which hydrophobic interaction is often involved. We examine the specific ion effect on the interaction of semihydrophobic nanoparticle with zwitterionic phospholipid bilayer in aqueous media added with different types of salts. Specifically, we compare the effect of different anions or cations on the adsorption of carboxyl-functionalized polystyrene nanoparticle on supported lipid bilayer and its induced bilayer disruption. By adding different anions at the same ionic concentration to the nanoparticle-lipid bilayer interface, we observe that the growth rate of nanoparticle-induced lipid-poor regions follows the exact Hofmeister anion order of CH3COO(-) > Cl(-) > NO3(-) ≫ SCN(-), suggesting the regulated hydrophobic interaction by anions. In contrast, the specific cation effect on nanoparticle-induced disruption rate of lipid bilayer does not follow the Hofmeister cation order and instead exhibits a trend of Cs(+) ∼ Rb(+) > Na(+) ≫ N(CH3)4(+). It is suggested that the effect of specific ions can be exploited as a simple and efficient approach to modify the nanoparticles-biomembrane interactions with the implication from drug delivery to nontoxic nanomaterial design. PMID:25337793

  8. Intra Nucleon Cascade Program

    Energy Science and Technology Software Center (ESTSC)

    1998-08-18

    The package consists of three programs ISABEL, EVA, and PACE-2. ISABEL and PACE-2 are part of the LAHET code. ISABEL is an intra-nucleon cascade program. The output cascades are used as directly as input files to the two evaporation programs EVA and PACE-2. EVA ignores the effect of the angular momentum of the excited nuclei on the deexcitation and also ignores the possibility of gamma emission as long as particle emission is energetically allowed. PACE-2more » takes full account of angular momentum effects including irast levels and gamma emission at all stages of the evaporation chain.« less

  9. The Effects of Sleep Continuity Disruption on Positive Mood and Sleep Architecture in Healthy Adults

    PubMed Central

    Finan, Patrick H.; Quartana, Phillip J.; Smith, Michael T.

    2015-01-01

    Objective: The purpose of this study was to test an experimental model of the effects of sleep continuity disturbance on sleep architecture and positive mood in order to better understand the mechanisms linking insomnia and depression. Design: Participants were randomized to receive 3 consecutive nights of sleep continuity disruption via forced nocturnal awakenings (FA, n = 21), or one of two control conditions: restricted sleep opportunity (RSO, n = 17) or uninterrupted sleep (US, n = 24). Setting: The study was set in an inpatient clinical research suite. Participants: Healthy, good-sleeping men and women were included. Measurement and Results: Polysomnography was used to measure sleep architecture, and mood was assessed via self-report each day. Compared to restricted sleep opportunity controls, forced awakenings subjects had significantly less slow wave sleep (P < 0.05) after the first night of sleep deprivation, and significantly lower positive mood (P < 0.05) after the second night of sleep deprivation. The differential change in slow wave sleep statistically mediated the observed group differences in positive mood (P = 0.002). Conclusions: To our knowledge, this is the first human experimental study to demonstrate that, despite comparable reductions in total sleep time, partial sleep loss from sleep continuity disruption is more detrimental to positive mood than partial sleep loss from delaying bedtime, even when controlling for concomitant increases in negative mood. With these findings, we provide temporal evidence in support of a putative biologic mechanism (slow wave sleep deficit) that could help explain the strong comorbidity between insomnia and depression. Citation: Finan PH, Quartana PJ, Smith MT. The effects of sleep continuity disruption on positive mood and sleep architecture in healthy adults. SLEEP 2015;38(11):1735–1742. PMID:26085289

  10. Estrogen disruption of neonatal ovine uterine development: effects on gene expression assessed by suppression subtraction hybridization.

    PubMed

    Hayashi, Kanako; Spencer, Thomas E

    2005-10-01

    Inappropriate exposure of neonatal sheep to estrogen during critical developmental periods inhibits or retards endometrial gland morphogenesis and reduces uterine growth. Studies were conducted to identify mechanisms mediating estrogen disruption of neonatal ovine uterine development by analysis of candidate growth factor systems and using suppression subtraction hybridization (SSH). In study 1, sheep were exposed either to corn oil as a control or to estradiol valerate (EV) from birth to Postnatal Day (PND) 14, which ablated endometrial gland development. Estradiol valerate decreased uterine FGF7 (fibroblast growth factor 7) and MET (hepatocyte growth factor receptor) expression and increased INHBA (inhibin betaA). The SSH identified a number of genes responsive to EV, which included GSTM3 (glutathione S-transferase), IDH1 (cytosolic NADP-isocitrate dehydrogenase), PECI (peroxisomal D(3),D(2)-enoyl-coenzyme A isomerase), OAS1 (2',5'-oligoadenylate 40/46-kDa synthetase), IGFBP3 (insulin-like growth factor-binding protein-3), TEGT (testis-enhanced gene transcript), CXCL10 (interferon-gamma-inducible protein 10), and IGLV (immunoglobulin V). These mRNAs were expressed predominantly in the endometrial epithelia (GSTM3, IDH1, PEC1, OAS1, and TEGT), stroma (IGFBP3), or immune cells (CXCL10 and IGLV). In study 2, effects of estrogen exposure on uterine gene expression were determined during three different critical developmental periods (PNDs 0-14, 14- 28, and 42-56). Estrogen exposure decreased expression of the SSH-identified genes, particularly those from PNDs 0-14. These studies suggest that estrogen disruption of postnatal uterine development involves period-specific effects on expression of genes predominantly in the endometrial epithelium. The SSH-identified, estrogen-disrupted genes represent new candidate regulators of postnatal endometrial adenogenesis. PMID:15972882

  11. Fokker-Planck simulation of runaway electron generation in disruptions with the hot-tail effect

    NASA Astrophysics Data System (ADS)

    Nuga, H.; Yagi, M.; Fukuyama, A.

    2016-06-01

    To study runaway electron generation in disruptions, we have extended the three-dimensional (two-dimensional in momentum space; one-dimensional in the radial direction) Fokker-Planck code, which describes the evolution of the relativistic momentum distribution function of electrons and the induced toroidal electric field in a self-consistent manner. A particular focus is placed on the hot-tail effect in two-dimensional momentum space. The effect appears if the drop of the background plasma temperature is sufficiently rapid compared with the electron-electron slowing down time for a few times of the pre-quench thermal velocity. It contributes to not only the enhancement of the primary runaway electron generation but also the broadening of the runaway electron distribution in the pitch angle direction. If the thermal energy loss during the major disruption is assumed to be isotropic, there are hot-tail electrons that have sufficiently large perpendicular momentum, and the runaway electron distribution becomes broader in the pitch angle direction. In addition, the pitch angle scattering also yields the broadening. Since the electric field is reduced due to the burst of runaway electron generation, the time required for accelerating electrons to the runaway region becomes longer. The longer acceleration period makes the pitch-angle scattering more effective.

  12. The effect of incidence angle on the overall three-dimensional aerodynamic performance of a classical annular airfoil cascade

    NASA Technical Reports Server (NTRS)

    Bergsten, D. E.; Fleeter, S.

    1983-01-01

    To be of quantitative value to the designer and analyst, it is necessary to experimentally verify the flow modeling and the numerics inherent in calculation codes being developed to predict the three dimensional flow through turbomachine blade rows. This experimental verification requires that predicted flow fields be correlated with three dimensional data obtained in experiments which model the fundamental phenomena existing in the flow passages of modern turbomachines. The Purdue Annular Cascade Facility was designed specifically to provide these required three dimensional data. The overall three dimensional aerodynamic performance of an instrumented classical airfoil cascade was determined over a range of incidence angle values. This was accomplished utilizing a fully automated exit flow data acquisition and analysis system. The mean wake data, acquired at two downstream axial locations, were analyzed to determine the effect of incidence angle, the three dimensionality of the cascade exit flow field, and the similarity of the wake profiles. The hub, mean, and tip chordwise airfoil surface static pressure distributions determined at each incidence angle are correlated with predictions from the MERIDL and TSONIC computer codes.

  13. Epigenetic effects of endocrine-disrupting chemicals on female reproduction: An ovarian perspective

    PubMed Central

    Zama, Aparna Mahakali; Uzumcu, Mehmet

    2010-01-01

    The link between in utero and neonatal exposure to environmental toxicants, such as endocrine-disrupting chemicals (EDCs) and adult female reproductive disorders is well established in both epidemiological and animal studies. Recent studies examining the epigenetic mechanisms involved in mediating the effects of EDCs on female reproduction are gathering momentum. In this review, we describe the developmental processes that are susceptible to EDC exposures in female reproductive system, with a special emphasis on the ovary. We discuss studies with select EDCs that have been shown to have physiological and correlated epigenetic effects in the ovary, neuroendocrine system, and uterus. Importantly, EDCs that can directly target the ovary can alter epigenetic mechanisms in the oocyte, leading to transgenerational epigenetic effects. The potential mechanisms involved in such effects are also discussed. PMID:20609371

  14. Contingent observation: an effective and acceptable procedure for reducing disruptive behavior of young children in a group setting.

    PubMed Central

    Porterfield, J K; Herbert-Jackson, E; Risley, T R

    1976-01-01

    Since a major task of childhood is learning to get along in a group without disrupting other children's activities, caregivers need explicit guidelines for gentle but effective procedures for dealing with disruptive behaviors in child-care settings. In a day-care center for normal 1- and 2-yr.-old children, an effort was made to develop a procedure that appeared sufficiently humane and educational to be acceptable to parents and day-care workers, and yet effective in reducing disruptive play behaviors. Caregivers used the occasion of disruptive behavior to instruct the child in appropriate alternatives, then had the child sit on the periphery and observe the appropriate social behavior of the other children "sit and watch", for a brief period before inviting him or her to rejoin the play activities. The effectiveness of this procedure was compared with a method commonly recommended for the use with young children: instructing the child, then distracting or redirecting the child to an alternative toy or activity. Contingent observation, combining instruction with a brief timeout (from being a participant in an activity to becoming an observer of the activity), proved considerably more effective in maintaining low levels of disruptions and was considered by caregivers and parents to be an appropriate and socially acceptable method of dealing with young children's disruptive behaviors. Therefore, contingent observation can be recommended for general use in day-care programs for young children. PMID:1254542

  15. The Effects of Mothers' Depression on the Behavioral Assessment of Disruptive Child Behavior.

    ERIC Educational Resources Information Center

    McFarland, Margaret L.; Sanders, Matthew R.

    2003-01-01

    This paper investigates some characteristics of families with disruptive children and depressed mothers, and compares the observed behaviors of disruptive children of depressed and non-depressed mothers. Differences observed suggest that, while children of depressed mothers employed a similar range of disruptive behaviors to other disruptive…

  16. ENDOCRINE-DISRUPTING CHEMICALS: PREPUBERTAL EXPOSURES AND EFFECTS ON SEXUAL MATURATION AND THYROID FUNCTION IN THE MALE RAT. A FOCUS ON THE EDSTAC RECOMMENDATIONS. ENDOCRINE DISRUPTER SCREENING AND TESTING ADVISORY COMMITTEE

    EPA Science Inventory

    Endocrine-disrupting chemicals: prepubertal exposures and effects on sexual maturation and thyroid function in the male rat. A focus on the EDSTAC recommendations. Endocrine Disrupter Screening and Testing Advisory Committee.

    Stoker TE, Parks LG, Gray LE, Cooper RL.

  17. Effects of copper on growth, metamorphosis and endocrine disruption of Bufo gargarizans larvae.

    PubMed

    Wang, Chao; Liang, Gang; Chai, Lihong; Wang, Hongyuan

    2016-01-01

    Chinese toad (Bufo gargarizans) tadpoles were exposed to copper (1, 6.4, 32 and 64μgL(-1) copper) from the beginning of larval period through completion of metamorphosis. We examined the effects of chronic copper exposure on mortality, growth, time to metamorphosis, tail resorption time, body size at the metamorphic climax (Gs 42) and completion of metamorphosis (Gs 46) and thyroid gland histology. In addition, type 2 and 3 iodothyronine deiodinase (Dio2 and Dio3), thyroid hormone receptors (TRα and TRβ) mRNA levels were also measured to assess disruption of TH synthesis. Our result showed that 6.4-64μgL(-1) copper concentration increased the mortality and inhibited the growth of B. gargarizans tadpoles. In addition, significant reduction in size at Gs 42 and a time delay to Gs 42 were observed at 6.4-64μgL(-1) copper treatments. Moreover, histological examinations have clearly revealed that 64μgL(-1) copper caused follicular cell hyperplasia in thyroid gland. According to real-time PCR results, exposure to 32 and 64μgL(-1) copper significantly up-regulated mRNA expression of Dio3, but down-regulated mRNA expression of TRα and TRβ mRNA level. We concluded that copper delayed amphibian metamorphosis through changing mRNA expression of Dio3, TRα and TRβ, which suggests that copper might have the endocrine-disrupting effect. PMID:26587739

  18. Effectiveness of Disruption Mitigation and Toroidal Asymmetry with Two Gas Jets

    NASA Astrophysics Data System (ADS)

    Granetz, R. S.; Olynyk, G. M.; Reinke, M. L.; Whyte, D. G.; Coombs, S.; Sugihara, M.

    2011-10-01

    Alcator C-Mod has done extensive disruption mitigation studies in the past using a high-pressure gas jet at a single toroidal location. Measurements with a pair of AXUV diode arrays (de facto solid-state bolometers) show that there can be a large toroidal asymmetry of the radiated power during mitigated disruptions. This is problematic for the ITER first wall, so ITER is planning to use multiple gas jets at a number of toroidal locations to reduce the asymmetric wall loading. To test the effectiveness of this concept, a 2nd gas jet is being added to Alcator C-Mod at a location around the torus from the existing jet. In addition, a toroidally distributed set of 5 AXUV diodes is being installed to provide enhanced toroidal resolution of radiated power. Experiments to measure the effect on toroidal asymmetry with the two gas jets will be performed early in the next campaign (fall 2011). Additional studies of other issues with two gas jets, such as mitigation of halo currrents and thermal loads, non-synchronous timing, different gas combinations, etc are also being planned. Supported by US DoE award DE-FC02-99ER54512.

  19. Sleep disruption and its effect on lymphocyte redeployment following an acute bout of exercise.

    PubMed

    Ingram, Lesley A; Simpson, Richard J; Malone, Eva; Florida-James, Geraint D

    2015-07-01

    Sleep disruption and deprivation are common in contemporary society and have been linked with poor health, decreased job performance and increased life-stress. The rapid redeployment of lymphocytes between the blood and tissues is an archetypal feature of the acute stress response, but it is not known if short-term perturbations in sleep architecture affect lymphocyte redeployment. We examined the effects of a disrupted night sleep on the exercise-induced redeployment of lymphocytes and their subtypes. 10 healthy male cyclists performed 1h of cycling at a fixed power output on an indoor cycle ergometer, following a night of undisrupted sleep (US) or a night of disrupted sleep (DS). Blood was collected before, immediately after and 1h after exercise completion. Lymphocytes and their subtypes were enumerated using direct immunofluorescence assays and 4-colour flow cytometry. DS was associated with elevated concentrations of total lymphocytes and CD3(-)/CD56(+) NK-cells. Although not affecting baseline levels, DS augmented the exercise-induced redeployment of CD8(+) T-cells, with the naïve/early differentiated subtypes (KLRG1(-)/CD45RA(+)) being affected most. While the mobilisation of cytotoxic lymphocyte subsets (NK cells, CD8(+) T-cells γδ T-cells), tended to be larger in response to exercise following DS, their enhanced egress at 1h post-exercise was more marked. This occurred despite similar serum cortisol and catecholamine levels between the US and DS trials. NK-cells redeployed with exercise after DS retained their expression of perforin and Granzyme-B indicating that DS did not affect NK-cell 'arming'. Our findings indicate that short-term changes in sleep architecture may 'prime' the immune system and cause minor enhancements in lymphocyte trafficking in response to acute dynamic exercise. PMID:25582807

  20. Environmental analysis of endocrine disrupting effects from hydrocarbon contaminants in the ecosystem. 1998 annual progress report

    SciTech Connect

    McLachlan, J.

    1998-06-01

    'The objective of this project is to determine how environmental contaminants, namely hydrocarbons, can act as hormones or anti-hormones (i.e., environmental hormones) in different species present in aquatic ecosystems. Species of particular focus are those which can serve as sentinel species (e.g., amphibians) and, thus, provide early warning signals for more widespread impacts on an ecosystem and its wildlife and human inhabitants. This reports the progress of 1.5 years of a three-year grant awarded to the Tulane/Xavier Center for Bioenvironmental Research (CBR). A growing body of evidence suggests that chemicals in the environment can disrupt the endocrine system of animals (i.e., wildlife and humans) and adversely impact the development of these species. Because of the multitude of known endocrine-disrupting chemicals and the numerous industrial and government sectors producing these chemicals, almost every federal agency has initiated research on the endocrine effects of chemicals relevant to their operations. This study represents the Department of Energy (DOE) Basic Energy Sciences'' only research on the impacts of endocrine-disrupting chemicals. The activities employed by this project to determine these impacts include development of biotechnology screens (in vitro), animal screens (in vivo), and other analyses of aquatic ecosystem biomarkers of exposure. The results from this study can elucidate how chemicals in the environment, including those from DOE activities, can signal (and alter) the development of a number of species in aquatic ecosystems. These signals can have detrimental impacts not only on an organismal level, but also on community, population, and entire ecosystem levels, including humans.'

  1. Effects of two-temperature model on cascade evolution in Ni and NiFe

    DOE PAGESBeta

    Samolyuk, German D.; Xue, Haizhou; Bei, Hongbin; Weber, William J.

    2016-07-05

    We perform molecular dynamics simulations of Ni ion cascades in Ni and equiatomic NiFe under the following conditions: (a) classical molecular dynamics (MD) simulations without consideration of electronic energy loss, (b) classical MD simulations with the electronic stopping included, and (c) using the coupled two-temperature MD (2T-MD) model that incorporates both the electronic stopping and the electron-phonon interactions. Our results indicate that the electronic e ects are more profound in the higher energy cascades and that the 2T-MD model results in a smaller amount of surviving damage and smaller defect clusters, while less damage is produced in NiFe than inmore » Ni.« less

  2. Resonant Cascaded Downconversion

    SciTech Connect

    Weedbrook, Christian; Parrett, Ben; Kheruntsyan, Karen; Drummond, Peter; Pooser, Raphael C; Pfister, Olivier

    2012-01-01

    We analyze an optical parametric oscillator (OPO) in which cascaded down-conversion occurs inside a cavity resonant for all modes but the initial pump. Due to the resonant cascade design, the OPO presents two {chi}{sup (2)}-level oscillation thresholds that are therefore much lower than for a {chi}{sup (3)} OPO. This is promising for reaching the regime of an effective third-order nonlinearity well above both thresholds. Such a {chi}{sup (2)} cascaded device also has potential applications in frequency conversion to far-infrared regimes. But, most importantly, it can generate novel multipartite quantum correlations in the output radiation, which represent a step beyond squeezed or entangled light. The output can be highly non-Gaussian and therefore not describable by any semiclassical model. In this paper, we derive quantum stochastic equations in the positive-P representation and undertake an analysis of steady-state and dynamical properties of this system.

  3. Effects of temporal correlations on cascades: Threshold models on temporal networks

    NASA Astrophysics Data System (ADS)

    Backlund, Ville-Pekka; Saramäki, Jari; Pan, Raj Kumar

    2014-06-01

    A person's decision to adopt an idea or product is often driven by the decisions of peers, mediated through a network of social ties. A common way of modeling adoption dynamics is to use threshold models, where a node may become an adopter given a high enough rate of contacts with adopted neighbors. We study the dynamics of threshold models that take both the network topology and the timings of contacts into account, using empirical contact sequences as substrates. The models are designed such that adoption is driven by the number of contacts with different adopted neighbors within a chosen time. We find that while some networks support cascades leading to network-level adoption, some do not: the propagation of adoption depends on several factors from the frequency of contacts to burstiness and timing correlations of contact sequences. More specifically, burstiness is seen to suppress cascade sizes when compared to randomized contact timings, while timing correlations between contacts on adjacent links facilitate cascades.

  4. Effects of orbital ellipticity on collisional disruptions of rubble-pile asteroids

    NASA Astrophysics Data System (ADS)

    Zhang, Yun; Baoyin, Hexi; Li, Junfeng; Richardson, Derek C.; Schwartz, Stephen R.

    2015-11-01

    The behavior of debris ejected from asteroids after collisional disruptions has significant implications for asteroid evolution. Analytical approximations of the elliptic restricted three-body system show that the behavior of ejecta varies significantly with the orbital eccentricity and true anomaly of an asteroid. To study these orbital perturbative effects on collision outcomes, we conduct a series of low-speed collision simulations using a combination of an N-body gravity algorithm and the soft-sphere discrete element method. The asteroid is modeled as a gravitational aggregate, which is one of the plausible structures for asteroids whose sizes are larger than several hundreds of meters. To reduce the effect of complicating factors raised by the mutual interaction between post-collision fragments on the outcomes, a low-resolution model and a set of frictionless material parameters are used in the first step of exploration. The results indicate that orbital perturbations on ejecta arising from the eccentricity and true anomaly of the target asteroid at the time of impact cause larger mass loss and lower the catastrophic disruption threshold (the specific energy required to disperse half the total system mass) in collision events. The "universal law" of catastrophic disruption derived by Stewart and Leinhardt (Astrophys. J. Lett. 691:L133-L137, 2009) can be applied to describe the collision outcomes of asteroids on elliptical heliocentric orbits. Through analyses of ejecta velocity distributions, we develop a semi-analytic description of escape speed from the asteroid's surface in an elliptic restricted three-body system and show that resulting perturbations have long-term orbital effects on ejecta and can also have an indirect influence on the velocity field of post-fragments through interparticle collisions. Further exploration with a high-resolution model shows that the long-term perturbative effects systematically increase mass loss, regardless of the target

  5. The Effect of Projectile Density and Disruption on the Crater Excavation Flow-Field

    NASA Technical Reports Server (NTRS)

    Anderson, Jennifer L. B.; Schultz, P. H.

    2005-01-01

    The ejection parameters of material excavated by a growing crater directly relate to the subsurface excavation flow-field. The ejection angles and speeds define the end of subsurface material streamlines at the target surface. Differences in the subsurface flow-fields can be inferred by comparing observed ejection parameters of various impacts obtained using three-dimensional particle image velocimetry (3D PIV). The work presented here investigates the observed ejection speeds and angles of material ejected during vertical (90 impact angle) experimental impacts for a range of different projectile types. The subsurface flow-fields produced during vertical impacts are simple when compared with that of oblique impacts, affected primarily by the depth of the energy and momentum deposition of the projectile. This depth is highly controlled by the projectile/target density ratio and the disruption of the projectile (brittle vs. ductile deformation). Previous studies indicated that cratering efficiency and the crater diameter/depth ratio were affected by projectile disruption, velocity, and the projectile/target density ratio. The effect of these projectile properties on the excavation flow-field are examined by comparing different projectile materials.

  6. Howling about Trophic Cascades

    ERIC Educational Resources Information Center

    Kowalewski, David

    2012-01-01

    Following evolutionary theory and an agriculture model, ecosystem research has stressed bottom-up dynamics, implying that top wild predators are epiphenomenal effects of more basic causes. As such, they are assumed expendable. A more modern co-evolutionary and wilderness approach--trophic cascades--instead suggests that top predators, whose…

  7. Disrupting morphosyntactic and lexical semantic processing has opposite effects on the sample entropy of neural signals.

    PubMed

    Fonseca, André; Boboeva, Vezha; Brederoo, Sanne; Baggio, Giosuè

    2015-04-16

    Converging evidence in neuroscience suggests that syntax and semantics are dissociable in brain space and time. However, it is possible that partly disjoint cortical networks, operating in successive time frames, still perform similar types of neural computations. To test the alternative hypothesis, we collected EEG data while participants read sentences containing lexical semantic or morphosyntactic anomalies, resulting in N400 and P600 effects, respectively. Next, we reconstructed phase space trajectories from EEG time series, and we measured the complexity of the resulting dynamical orbits using sample entropy - an index of the rate at which the system generates or loses information over time. Disrupting morphosyntactic or lexical semantic processing had opposite effects on sample entropy: it increased in the N400 window for semantic anomalies, and it decreased in the P600 window for morphosyntactic anomalies. These findings point to a fundamental divergence in the neural computations supporting meaning and grammar in language. PMID:25634797

  8. Stereotype threat in the classroom: dejection mediates the disrupting threat effect on women's math performance.

    PubMed

    Keller, Johannes; Dauenheimer, Dirk

    2003-03-01

    Research on stereotype threat, which is defined as the risk of confirming a negative stereotypic expectation about one's group, has demonstrated that the applicability of negative stereotypes disrupts the performance of stigmatized social groups. While it has been shown that a reduction of stereotype threat leads to improved performance by members of stigmatized groups, there is a lack of clear-cut findings about the mediating processes. The aim of the present study is to provide a better understanding of the mechanisms that stereotype threat causes in women working on mathematical problems. In addition, the study set out to test stereotype threat theory in a natural environment: high school classrooms. The experiment involved the manipulation of the gender fairness of a math test. The results indicate that the stereotype threat effect exists in this everyday setting. Moreover, it appears that dejection emotions mediate the effect of threat manipulation. PMID:15273014

  9. Endocrine-disrupting effect of the ultraviolet filter benzophenone-3 in zebrafish, Danio rerio.

    PubMed

    Kinnberg, Karin L; Petersen, Gitte I; Albrektsen, Mette; Minghlani, Mita; Awad, Suad Mohamud; Holbech, Bente F; Green, John W; Bjerregaard, Poul; Holbech, Henrik

    2015-12-01

    The chemical ultraviolet (UV) filter benzophenone-3 (BP-3) is suspected to be an endocrine disruptor based on results from in vitro and in vivo testing. However, studies including endpoints of endocrine adversity are lacking. The present study investigated the potential endocrine-disrupting effects of BP-3 in zebrafish (Danio rerio) in the Fish Sexual Development Test (Organisation for Economic Co-operation and Development TG 234) and a 12-d adult male zebrafish study. In TG 234, exposure from 0 d to 60 d posthatch caused a monotone dose-dependent skewing of the phenotypic sex ratio toward fewer males and more female zebrafish (no observed effect concentration [NOEC]: 191 μg/L, lowest observed effect concentration [LOEC]: 388 μg/L). Besides, gonad maturation was affected in both female fish (NOEC 191 μg/L, LOEC 388 μg/L) and male fish (NOEC 388 μg/L, LOEC 470 μg/L). Exposure to BP-3 did not affect the vitellogenin concentration in TG 234. After 12 d exposure of adult male zebrafish, a slight yet significant increase in the vitellogenin concentration was observed at 268 μg/L but not at 63 μg/L and 437 μg/L BP-3. Skewing of the sex ratio is a marker of an endocrine-mediated mechanism as well as a marker of adversity, and therefore the conclusion of the present study is that BP-3 is an endocrine-disrupting chemical in accordance with the World Health Organization's definition. PMID:26118430

  10. Continuity effects on rotifers and microcrustaceans caused by the construction of a downstream reservoir in a cascade series (Iguaçu River, Brazil).

    PubMed

    Serafim-Júnior, M; Lansac-Tôha, F A; Lopes, R M; Perbiche-Neves, G

    2016-06-01

    This study evaluated changes in the community of rotifers and microcrustaceans associated with the construction of a large and dendritic reservoir in Iguaçu River (Brazil), as the last reservoir of a sequence of five cascading systems. Differences were clear between pre-filling and post-filling phases for organisms and some of environmental variables. In the pre-filling phase, the community was more homogeneous along the downstream river gradient, and spatial compartmentalization in the new reservoir was common during the post-filling phase. From 140 identified taxa, 10 species occurred exclusively in the pre-filling phase and 32 in the post-filling phase. After completion of the fifth reservoir filling-up, opportunistic, pioneer and fast-developing species quickly dominated, and downstream of the fourth reservoir the pre-filling decreasing gradient of richness, diversity and evenness disappeared. Richness of rotifers and cladocerans, cladocerans diversity, and evenness of rotifers, cladocerans and copepods were generally higher in the post-filling phase. A non-metric multidimensional analysis based on a presence/absence matrix depicted a homogeneous and dense group of species associated to the pre-filling phase and a second, dispersed group related to the post-filling phase. Spearman correlations pointed out significant positive effects of transparency on rotifer species richness in the post-filling phase, and negative effects on the microcrustacean richness in the pre-filling phase. Dam construction caused disruption of the downstream lotic gradient along the series of dams, leading to the development of distinct species in lentic spatial compartments. PMID:26983084

  11. An in vitro investigation of endocrine disrupting effects of the mycotoxin alternariol

    SciTech Connect

    Frizzell, Caroline; Ndossi, Doreen; Kalayou, Shewit; Eriksen, Gunnar S.; Verhaegen, Steven; Sørlie, Morten; Elliott, Christopher T.; Ropstad, Erik; Connolly, Lisa

    2013-08-15

    Alternariol (AOH) is a mycotoxin commonly produced by Alternaria alternata on a wide range of foods. Few studies to date have been performed to evaluate the effects of AOH on endocrine activity. The present study makes use of in vitro mammalian cellular based assays and gene expression to investigate the ability of AOH to act as an endocrine disruptor by various modes of action. Reporter gene assays (RGAs), incorporating natural steroid hormone receptors for oestrogens, androgens, progestagens and glucocorticoids were used to identify endocrine disruption at the level of nuclear receptor transcriptional activity, and the H295R steroidogenesis assay was used to assess endocrine disruption at the level of gene expression and steroid hormone production. AOH exhibited a weak oestrogenic response when tested in the oestrogen responsive RGA and binding of progesterone to the progestagen receptor was shown to be synergistically increased in the presence of AOH. H295R cells when exposed to 0.1–1000 ng/ml AOH, did not cause a significant change in testosterone and cortisol hormones but exposure to 1000 ng/ml (3.87 μM) AOH resulted in a significant increase in estradiol and progesterone production. In the gene expression study following exposure to 1000 ng/ml (3.87 μM) AOH, only one gene NR0B1 was down-regulated, whereas expression of mRNA for CYP1A1, MC2R, HSD3B2, CYP17, CYP21, CYP11B2 and CYP19 was up-regulated. Expression of the other genes investigated did not change significantly. In conclusion AOH is a weak oestrogenic mycotoxin that also has the ability to interfere with the steroidogenesis pathway. - Highlights: • Alternariol was investigated for endocrine disrupting activity. • Reporter gene assays and the H295R steroidogenesis assay have been used. • An oestrogenic effect of alternariol was observed. • This can lead to an increase in expression of the progesterone receptor. • Alternariol is capable of modulating hormone production and gene expression.

  12. The disruptive – and beneficial – effects of distraction on older adults’ cognitive performance

    PubMed Central

    Weeks, Jennifer C.; Hasher, Lynn

    2014-01-01

    Older adults’ decreased ability to inhibit irrelevant information makes them especially susceptible to the negative effects of simultaneously occurring distraction. For example, older adults are more likely than young adults to process distraction presented during a task, which can result in delayed response times, decreased reading comprehension, disrupted problem solving, and reduced memory for target information. However, there is also some evidence that the tendency to process distraction can actually facilitate older adults’ performance when the distraction is congruent with the target information. For example, congruent distraction can speed response times, increase reading comprehension, benefit problem solving, and reduce forgetting in older adults. We review data showing that incongruent distraction can harm older adults’ performance, as well as evidence suggesting that congruent distraction can play a supportive role for older adults by facilitating processing of target information. Potential applications of distraction processing are also discussed. PMID:24634662

  13. Bidirectional-Compounding Effects of Rumination and Negative Emotion in Predicting Impulsive Behavior: Implications for Emotional Cascades.

    PubMed

    Selby, Edward A; Kranzler, Amy; Panza, Emily; Fehling, Kara B

    2016-04-01

    Influenced by chaos theory, the emotional cascade model proposes that rumination and negative emotion may promote each other in a self-amplifying cycle that increases over time. Accordingly, exponential-compounding effects may better describe the relationship between rumination and negative emotion when they occur in impulsive persons, and predict impulsive behavior. Forty-seven community and undergraduate participants who reported frequent engagement in impulsive behaviors monitored their ruminative thoughts and negative emotion multiple times daily for two weeks using digital recording devices. Hypotheses were tested using cross-lagged mixed model analyses. Findings indicated that rumination predicted subsequent elevations in rumination that lasted over extended periods of time. Rumination and negative emotion predicted increased levels of each other at subsequent assessments, and exponential functions for these associations were supported. Results also supported a synergistic effect between rumination and negative emotion, predicting larger elevations in subsequent rumination and negative emotion than when one variable alone was elevated. Finally, there were synergistic effects of rumination and negative emotion in predicting number of impulsive behaviors subsequently reported. These findings are consistent with the emotional cascade model in suggesting that momentary rumination and negative emotion progressively propagate and magnify each other over time in impulsive people, promoting impulsive behavior. PMID:25388298

  14. Endocrine Disrupting Effects of Triclosan on the Placenta in Pregnant Rats

    PubMed Central

    Zhang, Zhaobin; Shi, Jiachen; Jiao, Zhihao; Shao, Bing

    2016-01-01

    Triclosan (TCS) is a broad-spectrum antimicrobial agent that is frequently used in pharmaceuticals and personal care products. Reports have shown that TCS is a potential endocrine disruptor; however, the potential effects of TCS on placental endocrine function are unclear. The aim of this study was to investigate the endocrine disrupting effects of TCS on the placenta in pregnant rats. Pregnant rats from gestational day (GD) 6 to GD 20 were treated with 0, 30, 100, 300 and 600 mg/kg/d TCS followed by analysis of various biochemical parameters. Of the seven tissues examined, the greatest bioaccumulation of TCS was observed in the placenta. Reduction of gravid uterine weight and the occurrence of abortion were observed in the 600 mg/kg/d TCS-exposed group. Moreover, hormone detection demonstrated that the serum levels of progesterone (P), estradiol (E2), testosterone (T), human chorionic gonadotropin (hCG) and prolactin (PRL) were decreased in groups exposed to higher doses of TCS. Real-time quantitative reverse transcriptase-polymerase chain reaction (Q-RT-PCR) analysis revealed a significant increase in mRNA levels for placental steroid metabolism enzymes, including UDP-glucuronosyltransferase 1A1 (UGT1A1), estrogen sulfotransferase 1E1 (SULT1E1), steroid 5α-reductase 1 (SRD5A1) and steroid 5α-reductase 2 (SRD5A2). Furthermore, the transcriptional expression levels of progesterone receptor (PR), estrogen receptor (ERα) and androgen receptor (AR) were up-regulated. Taken together, these data demonstrated that the placenta was a target tissue of TCS and that TCS induced inhibition of circulating steroid hormone production might be related to the altered expression of hormone metabolism enzyme genes in the placenta. This hormone disruption might subsequently affect fetal development and growth. PMID:27149376

  15. Endothelial disruptive proinflammatory effects of nicotine and e-cigarette vapor exposures.

    PubMed

    Schweitzer, Kelly S; Chen, Steven X; Law, Sarah; Van Demark, Mary; Poirier, Christophe; Justice, Matthew J; Hubbard, Walter C; Kim, Elena S; Lai, Xianyin; Wang, Mu; Kranz, William D; Carroll, Clinton J; Ray, Bruce D; Bittman, Robert; Goodpaster, John; Petrache, Irina

    2015-07-15

    The increased use of inhaled nicotine via e-cigarettes has unknown risks to lung health. Having previously shown that cigarette smoke (CS) extract disrupts the lung microvasculature barrier function by endothelial cell activation and cytoskeletal rearrangement, we investigated the contribution of nicotine in CS or e-cigarettes (e-Cig) to lung endothelial injury. Primary lung microvascular endothelial cells were exposed to nicotine, e-Cig solution, or condensed e-Cig vapor (1-20 mM nicotine) or to nicotine-free CS extract or e-Cig solutions. Compared with nicotine-containing extract, nicotine free-CS extract (10-20%) caused significantly less endothelial permeability as measured with electric cell-substrate impedance sensing. Nicotine exposures triggered dose-dependent loss of endothelial barrier in cultured cell monolayers and rapidly increased lung inflammation and oxidative stress in mice. The endothelial barrier disruptive effects were associated with increased intracellular ceramides, p38 MAPK activation, and myosin light chain (MLC) phosphorylation, and was critically mediated by Rho-activated kinase via inhibition of MLC-phosphatase unit MYPT1. Although nicotine at sufficient concentrations to cause endothelial barrier loss did not trigger cell necrosis, it markedly inhibited cell proliferation. Augmentation of sphingosine-1-phosphate (S1P) signaling via S1P1 improved both endothelial cell proliferation and barrier function during nicotine exposures. Nicotine-independent effects of e-Cig solutions were noted, which may be attributable to acrolein, detected along with propylene glycol, glycerol, and nicotine by NMR, mass spectrometry, and gas chromatography, in both e-Cig solutions and vapor. These results suggest that soluble components of e-Cig, including nicotine, cause dose-dependent loss of lung endothelial barrier function, which is associated with oxidative stress and brisk inflammation. PMID:25979079

  16. Endocrine Disrupting Effects of Triclosan on the Placenta in Pregnant Rats.

    PubMed

    Feng, Yixing; Zhang, Pin; Zhang, Zhaobin; Shi, Jiachen; Jiao, Zhihao; Shao, Bing

    2016-01-01

    Triclosan (TCS) is a broad-spectrum antimicrobial agent that is frequently used in pharmaceuticals and personal care products. Reports have shown that TCS is a potential endocrine disruptor; however, the potential effects of TCS on placental endocrine function are unclear. The aim of this study was to investigate the endocrine disrupting effects of TCS on the placenta in pregnant rats. Pregnant rats from gestational day (GD) 6 to GD 20 were treated with 0, 30, 100, 300 and 600 mg/kg/d TCS followed by analysis of various biochemical parameters. Of the seven tissues examined, the greatest bioaccumulation of TCS was observed in the placenta. Reduction of gravid uterine weight and the occurrence of abortion were observed in the 600 mg/kg/d TCS-exposed group. Moreover, hormone detection demonstrated that the serum levels of progesterone (P), estradiol (E2), testosterone (T), human chorionic gonadotropin (hCG) and prolactin (PRL) were decreased in groups exposed to higher doses of TCS. Real-time quantitative reverse transcriptase-polymerase chain reaction (Q-RT-PCR) analysis revealed a significant increase in mRNA levels for placental steroid metabolism enzymes, including UDP-glucuronosyltransferase 1A1 (UGT1A1), estrogen sulfotransferase 1E1 (SULT1E1), steroid 5α-reductase 1 (SRD5A1) and steroid 5α-reductase 2 (SRD5A2). Furthermore, the transcriptional expression levels of progesterone receptor (PR), estrogen receptor (ERα) and androgen receptor (AR) were up-regulated. Taken together, these data demonstrated that the placenta was a target tissue of TCS and that TCS induced inhibition of circulating steroid hormone production might be related to the altered expression of hormone metabolism enzyme genes in the placenta. This hormone disruption might subsequently affect fetal development and growth. PMID:27149376

  17. Effects of ZnO nanoparticles on perfluorooctane sulfonate induced thyroid-disrupting on zebrafish larvae.

    PubMed

    Du, Jia; Wang, Shutao; You, Hong; Liu, Zhongqiang

    2016-09-01

    Perfluorooctane sulfonate (PFOS) and ZnO nanoparticles (nano-ZnO) are widely distributed in the environment. However, the potential toxicity of co-exposure to PFOS and nano-ZnO remains to be fully elucidated. The test investigated the effects of co-exposure to PFOS and nano-ZnO on the hypothalamic-pituitary-thyroid (HPT) axis in zebrafish. Zebrafish embryos were exposed to a combination of PFOS (0.2, 0.4, 0.8mg/L) and nano-ZnO (50mg/L) from their early stages of life (0-14days). The whole-body content of TH and the expression of genes and proteins related to the HPT axis were analyzed. The co-exposure decreased the body length and increased the malformation rates compared with exposure to PFOS alone. Co-exposure also increased the triiodothyronine (T3) levels, whereas the thyroxine (T4) content remained unchanged. Compared with the exposure to PFOS alone, exposure to both PFOS (0.8mg/L) and nano-ZnO (50mg/L) significantly up-regulated the expression of corticotropin-releasing factor, sodium/iodidesymporter, iodothyronine deiodinases and thyroid receptors and significantly down-regulated the expression of thyroid-stimulating hormone, thyroglobulin (TG), transthyretin (TTR) and thyroid receptors. The protein expression levels of TG and TTR were also significantly down-regulated in the co-exposure groups. In addition, the expression of the thyroid peroxidase gene was unchanged in all groups. The results demonstrated that PFOS and nano-ZnO co-exposure could cause more serious thyroid-disrupting effects in zebrafish than exposure to PFOS alone. Our results also provide insight into the mechanism of disruption of the thyroid status by PFOS and nano-ZnO. PMID:27593282

  18. Endothelial disruptive proinflammatory effects of nicotine and e-cigarette vapor exposures

    PubMed Central

    Schweitzer, Kelly S.; Chen, Steven X.; Law, Sarah; Van Demark, Mary; Poirier, Christophe; Justice, Matthew J.; Hubbard, Walter C.; Kim, Elena S.; Lai, Xianyin; Wang, Mu; Kranz, William D.; Carroll, Clinton J.; Ray, Bruce D.; Bittman, Robert; Goodpaster, John

    2015-01-01

    The increased use of inhaled nicotine via e-cigarettes has unknown risks to lung health. Having previously shown that cigarette smoke (CS) extract disrupts the lung microvasculature barrier function by endothelial cell activation and cytoskeletal rearrangement, we investigated the contribution of nicotine in CS or e-cigarettes (e-Cig) to lung endothelial injury. Primary lung microvascular endothelial cells were exposed to nicotine, e-Cig solution, or condensed e-Cig vapor (1–20 mM nicotine) or to nicotine-free CS extract or e-Cig solutions. Compared with nicotine-containing extract, nicotine free-CS extract (10–20%) caused significantly less endothelial permeability as measured with electric cell-substrate impedance sensing. Nicotine exposures triggered dose-dependent loss of endothelial barrier in cultured cell monolayers and rapidly increased lung inflammation and oxidative stress in mice. The endothelial barrier disruptive effects were associated with increased intracellular ceramides, p38 MAPK activation, and myosin light chain (MLC) phosphorylation, and was critically mediated by Rho-activated kinase via inhibition of MLC-phosphatase unit MYPT1. Although nicotine at sufficient concentrations to cause endothelial barrier loss did not trigger cell necrosis, it markedly inhibited cell proliferation. Augmentation of sphingosine-1-phosphate (S1P) signaling via S1P1 improved both endothelial cell proliferation and barrier function during nicotine exposures. Nicotine-independent effects of e-Cig solutions were noted, which may be attributable to acrolein, detected along with propylene glycol, glycerol, and nicotine by NMR, mass spectrometry, and gas chromatography, in both e-Cig solutions and vapor. These results suggest that soluble components of e-Cig, including nicotine, cause dose-dependent loss of lung endothelial barrier function, which is associated with oxidative stress and brisk inflammation. PMID:25979079

  19. Cascading effects of interparental conflict in adolescence: Linking threat appraisals, self-efficacy, and adjustment.

    PubMed

    Fosco, Gregory M; Feinberg, Mark E

    2015-02-01

    This study examined the longitudinal implications of adolescents' exposure to interparental conflict for their developmental success. In the proposed developmental cascade model, adolescents' perceptions of parental conflict as threatening is a risk factor for diminished self-efficacy, which would account for diminished adjustment. This study presents longitudinal data for 768 sixth-grade students and their families over four time points, ending in eighth grade. Analyses were conducted in three steps. First, replication of longitudinal support for threat as a mediator of the link between interparental conflict and emotional distress was found; however, findings did not support threat as a mediator of behavior problems or subjective well-being. Second, threat was found to mediate the longitudinal association between interparental conflict and self-efficacy. Third, a developmental cascade model supported a risk process in which interparental conflict was related to adolescents' threat appraisals, which undermined self-efficacy beliefs, and was then linked with emotional distress, behavior problems, and subjective well-being. PMID:25017469

  20. Cascading effects of insectivorous birds and bats in tropical coffee plantations.

    PubMed

    Karp, Daniel S; Daily, Gretchen C

    2014-04-01

    The loss of apex predators is known to have reverberating consequences for ecosystems, but how changes in broader predator assemblages affect vital ecosystem functions and services is largely unknown. Predators and their prey form complex interaction networks, in which predators consume not only herbivores but also other predators. Resolving these interactions will be essential for predicting changes in many important ecosystem functions, such as the control of damaging crop pests. Here, we examine how birds, bats, and arthropods interact to determine herbivorous arthropod abundance and leaf damage in Costa Rican coffee plantations. In an exclosure experiment, we found that birds and bats reduced non-flying arthropod abundance by -35% and -25%, respectively. In contrast, birds and bats increased the abundance of flying arthropods, probably by consuming spiders. The frequency of this intraguild predation differed between birds and bats, with cascading consequences for coffee shrubs. Excluding birds caused a greater increase in herbivorous arthropod abundance than excluding bats, leading to increased coffee leaf damage. Excluding bats caused an increase in spiders and other predatory arthropods, increasing the ratio of predators to herbivores in the arthropod community. Bats, therefore, did not provide benefits to coffee plants. Leaf damage on coffee was low, and probably did not affect coffee yields. Bird-mediated control of herbivores, however, may aid coffee shrubs in the long-term by preventing pest outbreaks. Regardless, our results demonstrate how complex, cascading interactions between predators and herbivores may impact plants and people. PMID:24933824

  1. Effects of Four Different Regulatory Mechanisms on the Dynamics of Gene Regulatory Cascades

    PubMed Central

    Hansen, Sabine; Krishna, Sandeep; Semsey, Szabolcs; Lo Svenningsen, Sine

    2015-01-01

    Gene regulatory cascades (GRCs) are common motifs in cellular molecular networks. A given logical function in these cascades, such as the repression of the activity of a transcription factor, can be implemented by a number of different regulatory mechanisms. The potential consequences for the dynamic performance of the GRC of choosing one mechanism over another have not been analysed systematically. Here, we report the construction of a synthetic GRC in Escherichia coli, which allows us for the first time to directly compare and contrast the dynamics of four different regulatory mechanisms, affecting the transcription, translation, stability, or activity of a transcriptional repressor. We developed a biologically motivated mathematical model which is sufficient to reproduce the response dynamics determined by experimental measurements. Using the model, we explored the potential response dynamics that the constructed GRC can perform. We conclude that dynamic differences between regulatory mechanisms at an individual step in a GRC are often concealed in the overall performance of the GRC, and suggest that the presence of a given regulatory mechanism in a certain network environment does not necessarily mean that it represents a single optimal evolutionary solution. PMID:26184971

  2. Effects of Four Different Regulatory Mechanisms on the Dynamics of Gene Regulatory Cascades

    NASA Astrophysics Data System (ADS)

    Hansen, Sabine; Krishna, Sandeep; Semsey, Szabolcs; Lo Svenningsen, Sine

    2015-07-01

    Gene regulatory cascades (GRCs) are common motifs in cellular molecular networks. A given logical function in these cascades, such as the repression of the activity of a transcription factor, can be implemented by a number of different regulatory mechanisms. The potential consequences for the dynamic performance of the GRC of choosing one mechanism over another have not been analysed systematically. Here, we report the construction of a synthetic GRC in Escherichia coli, which allows us for the first time to directly compare and contrast the dynamics of four different regulatory mechanisms, affecting the transcription, translation, stability, or activity of a transcriptional repressor. We developed a biologically motivated mathematical model which is sufficient to reproduce the response dynamics determined by experimental measurements. Using the model, we explored the potential response dynamics that the constructed GRC can perform. We conclude that dynamic differences between regulatory mechanisms at an individual step in a GRC are often concealed in the overall performance of the GRC, and suggest that the presence of a given regulatory mechanism in a certain network environment does not necessarily mean that it represents a single optimal evolutionary solution.

  3. Cascading Effects of Interparental Conflict in Adolescence: Linking Threat Appraisals, Self-Efficacy, and Adjustment

    PubMed Central

    Fosco, Gregory M.; Feinberg, Mark E.

    2015-01-01

    This study examined the longitudinal implications of adolescents’ exposure to interparental conflict for their developmental success. In the proposed developmental cascade model, adolescents’ perceptions of parental conflict as threatening is a risk factor for diminished self-efficacy, which would account for diminished adjustment. This study presents longitudinal data for 768 6th-grade students and their families over four time points, ending in 8th grade. Analyses were conducted in three steps. First, replication of longitudinal support for threat as a mediator of the link between interparental conflict and emotional distress was found; however, findings did not support threat as a mediator of behavior problems or subjective well-being. Second, threat was found to mediate the longitudinal association between interparental conflict and self-efficacy. Finally, a developmental cascade model supported a risk process in which interparental conflict was related to adolescents’ threat appraisals, which undermined self-efficacy beliefs, and was then linked with emotional distress, behavior problems, and subjective well-being. PMID:25017469

  4. Ten Years of Mixing Cocktails: A Review of Combination Effects of Endocrine-Disrupting Chemicals

    PubMed Central

    Kortenkamp, Andreas

    2007-01-01

    In the last 10 years, good evidence has become available to show that the combined effects of endocrine disruptors (EDs) belonging to the same category (e.g., estrogenic, antiandrogenic, or thyroid-disrupting agents) can be predicted by using dose addition. This is true for a variety of end points representing a wide range of organizational levels and biological complexity. Combinations of EDs are able to produce significant effect, even when each chemical is present at low doses that individually do not induce observable effects. However, comparatively little is known about mixtures composed of chemicals from different classes of EDs. Nevertheless, I argue that the accumulated evidence seriously undermines continuation with the customary chemical-by-chemical approach to risk assessment for EDs. Instead, we should seriously consider group-wise regulation of classes of EDs. Great care should be taken to define such classes by using suitable similarity criteria. Criteria should focus on common effects, rather than common mechanisms. In this review I also highlight research needs and identify the lack of information about exposure scenarios as a knowledge gap that seriously hampers progress with ED risk assessment. Future research should focus on investigating the effects of combinations of EDs from different categories, with considerable emphasis on elucidating mechanisms. This strategy may lead to better-defined criteria for grouping EDs for regulatory purposes. Also, steps should be taken to develop dedicated mixtures exposure assessment for EDs. PMID:18174957

  5. Effects of particle mixing and scattering in the dusty gas flow through moving and stationary cascades of airfoils

    NASA Astrophysics Data System (ADS)

    Tsirkunov, Yu. M.; Romanyuk, D. A.; Panfilov, S. V.

    2011-10-01

    Time-dependent two-dimensional (2D) flow of dusty gas through a set of two cascades of airfoils (blades) has been studied numerically. The first cascade was assumed to move (rotor) and the second one to be immovable (stator). Such a flow can be considered, in some sense, as a flow in the inlet stage of a turbomachine, for example, in the inlet compressor of an aircraft turbojet engine. Dust particle concentration was assumed to be very low, so that the interparticle collisions and the effect of the dispersed phase on the carrier gas were negligible. Flow of the carrier gas was described by full Navier-Stokes equations. In calculations of particle motion, the particles were considered as solid spheres. The particle drag force, transverse Magnus force, and damping torque were taken into account in the model of gas-particle interaction. The impact interaction of particles with blades was considered as frictional and partly elastic. The effects of particle size distribution and particle scattering in the course of particle-blade collisions were investigated. Flow fields of the carrier gas and flow patterns of the particle phase were obtained and discussed.

  6. Differential Effects of Seating Arrangements on Disruptive Behavior of Fifth Grade Students during Independent Seatwork

    ERIC Educational Resources Information Center

    Bicard, David F.; Ervin, Angela; Bicard, Sara C.; Baylot-Casey, Laura

    2012-01-01

    We investigated teacher versus student seat selection in the context of group and individual seating arrangements. Disruptive behavior during group seating occurred at twice the rate when students chose their seats than when the teacher chose. During individual seating, disruptive behavior occurred more than three times as often when the students…

  7. Cumulative Effects of Mothers' Risk and Promotive Factors on Daughters' Disruptive Behavior

    ERIC Educational Resources Information Center

    van der Molen, Elsa; Hipwell, Alison E.; Vermeiren, Robert; Loeber, Rolf

    2012-01-01

    Little is known about the ways in which the accumulation of maternal factors increases or reduces risk for girls' disruptive behavior during preadolescence. In the current study, maternal risk and promotive factors and the severity of girls' disruptive behavior were assessed annually among girls' ages 7-12 in an urban community sample (N = 2043).…

  8. Constructive Disruptions for Effective Collaborative Learning: Navigating the Affordances of Social Media for Meaningful Engagement

    ERIC Educational Resources Information Center

    Rambe, Patient

    2012-01-01

    The essentialist view that new technological innovations (especially Social Media) disrupt higher education delivery ride on educators' risk averse attitudes toward full scale adoption of unproven technologies. However, this unsubstantiated logic forecloses possibilities for embracing the constructive dimensions of disruptions, and grasping the…

  9. Effect of a Surrounding Liquid Environment on the Electrical Disruption of Pendant Droplets.

    PubMed

    Mohamed, A Said; Lopez-Herrera, Jose M; Herrada, Miguel A; Modesto-Lopez, Luis B; Gañán-Calvo, Alfonso M

    2016-07-12

    The effect of a surrounding, dielectric, liquid environment on the dynamics of a suddenly electrified liquid drop is investigated both numerically and experimentally. The onset of stability of the droplet is naturally dictated by a threshold value of the applied electric field. While below that threshold the droplet retains its integrity, reaching to a new equilibrium state through damped oscillations (subcritical regime), above it electrical disruption takes place (supercritical regime). In contrast to the oscillation regime, the dynamics of the electric droplet disruption in the supercritical regime reveals a variety of modes. Depending on the operating parameters and fluid properties, a drop in the supercritical regime may result in the well-known tip streaming mode (with and without whipping instability), in droplet splitting (splitting mode), or in the development of a steep shoulder at the elongating front of the droplet that expands radially in a sort of "splashing" (splashing mode). In both splitting and splashing modes, the sizes of the progeny droplets, generated after the breakup of the mother droplet, are comparable to that of the mother droplet. Furthermore, the development in the emission process of the shoulder leading to the splashing mode is described as a parametrical bifurcation, and the parameter governing that bifurcation has been identified. Physical analysis confirms the unexpected experimental finding that the viscosity of the dynamically active environment is absent in the governing parameter. However, the appearance of the splitting mode is determined by the viscosity of the outer environment, when that viscosity overcomes a certain large value. These facts point to the highly nonlinear character of the drop fission process as a function of the droplet volume, inner and outer liquid viscosities, and applied electric field. These observations may have direct implications in systems where precise control of the droplet size is critical, such

  10. Bad prospects for the detection of giant stars' tidal disruption: effect of the ambient medium on bound debris

    NASA Astrophysics Data System (ADS)

    Bonnerot, Clément; Rossi, Elena M.; Lodato, Giuseppe

    2016-05-01

    Most massive galaxies are thought to contain a supermassive black hole in their centre surrounded by a tenuous gas environment, leading to no significant emission. In these quiescent galaxies, tidal disruption events represent a powerful detection method for the central black hole. Following the disruption, the stellar debris evolves into an elongated gas stream, which partly falls back towards the disruption site and accretes on to the black hole producing a luminous flare. Using an analytical treatment, we investigate the interaction between the debris stream and the gas environment of quiescent galaxies. Although we find dynamical effects to be negligible, we demonstrate that Kelvin-Helmholtz instability can lead to the dissolution of the stream into the ambient medium before it reaches the black hole, likely dimming the associated flare. This result is robust against the presence of a typical stellar magnetic field and fast cooling within the stream. Furthermore, we find this effect to be enhanced for disruptions involving more massive black holes and/or giant stars. Consequently, although disruptions of evolved stars have been proposed as a useful probe of black holes with masses ≳ 108 M⊙, we argue that the associated flares are likely less luminous than expected.

  11. The disruptive effects of pain on complex cognitive performance and executive control.

    PubMed

    Keogh, Edmund; Moore, David J; Duggan, Geoffrey B; Payne, Stephen J; Eccleston, Christopher

    2013-01-01

    Pain interferes and disrupts attention. What is less clear is how pain affects performance on complex tasks, and the strategies used to ensure optimal outcomes. The aim of the current study was to examine the effect of pain on higher-order executive control processes involved in managing complex tasks. Sixty-two adult volunteers (40 female) completed two computer-based tasks: a breakfast making task and a word generation puzzle. Both were complex, involving executive control functions, including goal-directed planning and switching. Half of those recruited performed the tasks under conditions of thermal heat pain, and half with no accompanying pain. Whilst pain did not affect central performance on either task, it did have indirect effects. For the breakfast task, pain resulted in a decreased ability to multitask, with performance decrements found on the secondary task. However, no effects of pain were found on the processes thought to underpin this task. For the word generation puzzle, pain did not affect task performance, but did alter subjective accounts of the processes used to complete the task; pain affected the perceived allocation of time to the task, as well as switching perceptions. Sex differences were also found. When studying higher-order cognitive processes, pain-related interference effects are varied, and may result in subtle or indirect changes in cognition. PMID:24386168

  12. Hormones and Endocrine-Disrupting Chemicals: Low-Dose Effects and Nonmonotonic Dose Responses

    PubMed Central

    Colborn, Theo; Hayes, Tyrone B.; Heindel, Jerrold J.; Jacobs, David R.; Lee, Duk-Hee; Shioda, Toshi; Soto, Ana M.; vom Saal, Frederick S.; Welshons, Wade V.; Zoeller, R. Thomas

    2012-01-01

    For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of “the dose makes the poison,” because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature. We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health. PMID:22419778

  13. Hormones and endocrine-disrupting chemicals: low-dose effects and nonmonotonic dose responses.

    PubMed

    Vandenberg, Laura N; Colborn, Theo; Hayes, Tyrone B; Heindel, Jerrold J; Jacobs, David R; Lee, Duk-Hee; Shioda, Toshi; Soto, Ana M; vom Saal, Frederick S; Welshons, Wade V; Zoeller, R Thomas; Myers, John Peterson

    2012-06-01

    For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of "the dose makes the poison," because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature. We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health. PMID:22419778

  14. Effects of mistuning on bending-torsion flutter and response of a cascade in incompressible flow. [turbofan engines

    NASA Technical Reports Server (NTRS)

    Kaza, K. R. V.; Kielb, R. E.

    1981-01-01

    The effect of small differences between the individual blades (mistuning) on the aeroelastic stability and response of a cascade were studied. The aerodynamic, inertial, and structural coupling between the bending and torsional motions of each blade and the aerodynamic coupling between the blades was considered. A digital computer program was developed to conduct parametric studies. Results indicate that the mistuning has a beneficial effect on the coupled bending torsion and uncoupled torsion flutter. On forced response, however, the effect may be either beneficial or adverse, depending on the engine order of the forcing function. The results also illustrate that it may be feasible to utilize mistuning as a passive control to increase flutter speed while maintaining forced response at an acceptable level.

  15. The virus's tooth: cyanophages affect an African flamingo population in a bottom-up cascade

    PubMed Central

    Peduzzi, Peter; Gruber, Martin; Gruber, Michael; Schagerl, Michael

    2014-01-01

    Trophic cascade effects occur when a food web is disrupted by loss or significant reduction of one or more of its members. In East African Rift Valley lakes, the Lesser Flamingo is on top of a short food chain. At irregular intervals, the dominance of their most important food source, the cyanobacterium Arthrospira fusiformis, is interrupted. Bacteriophages are known as potentially controlling photoautotrophic bacterioplankton. In Lake Nakuru (Kenya), we found the highest abundance of suspended viruses ever recorded in a natural aquatic system. We document that cyanophage infection and the related breakdown of A. fusiformis biomass led to a dramatic reduction in flamingo abundance. This documents that virus infection at the very base of a food chain can affect, in a bottom-up cascade, the distribution of end consumers. We anticipate this as an important example for virus-mediated cascading effects, potentially occurring also in various other aquatic food webs. PMID:24430484

  16. Mutualism Disruption Threatens Global Plant Biodiversity: A Systematic Review

    PubMed Central

    Aslan, Clare E.; Zavaleta, Erika S.; Tershy, Bernie; Croll, Donald

    2013-01-01

    Background As global environmental change accelerates, biodiversity losses can disrupt interspecific interactions. Extinctions of mutualist partners can create “widow” species, which may face reduced ecological fitness. Hypothetically, such mutualism disruptions could have cascading effects on biodiversity by causing additional species coextinctions. However, the scope of this problem – the magnitude of biodiversity that may lose mutualist partners and the consequences of these losses – remains unknown. Methodology/Principal Findings We conducted a systematic review and synthesis of data from a broad range of sources to estimate the threat posed by vertebrate extinctions to the global biodiversity of vertebrate-dispersed and -pollinated plants. Though enormous research gaps persist, our analysis identified Africa, Asia, the Caribbean, and global oceanic islands as geographic regions at particular risk of disruption of these mutualisms; within these regions, percentages of plant species likely affected range from 2.1–4.5%. Widowed plants are likely to experience reproductive declines of 40–58%, potentially threatening their persistence in the context of other global change stresses. Conclusions Our systematic approach demonstrates that thousands of species may be impacted by disruption in one class of mutualisms, but extinctions will likely disrupt other mutualisms, as well. Although uncertainty is high, there is evidence that mutualism disruption directly threatens significant biodiversity in some geographic regions. Conservation measures with explicit focus on mutualistic functions could be necessary to bolster populations of widowed species and maintain ecosystem functions. PMID:23840571

  17. Deep turbulence effects compensation experiments with a cascaded adaptive optics system using a 3.63 m telescope.

    PubMed

    Vorontsov, Mikhail; Riker, Jim; Carhart, Gary; Gudimetla, V S Rao; Beresnev, Leonid; Weyrauch, Thomas; Roberts, Lewis C

    2009-01-01

    Compensation of extended (deep) turbulence effects is one of the most challenging problems in adaptive optics (AO). In the AO approach described, the deep turbulence wave propagation regime was achieved by imaging stars at low elevation angles when image quality improvement with conventional AO was poor. These experiments were conducted at the U.S. Air Force Maui Optical and Supercomputing Site (AMOS) by using the 3.63 m telescope located on Haleakala, Maui. To enhance compensation performance we used a cascaded AO system composed of a conventional AO system based on a Shack-Hartmann wavefront sensor and a deformable mirror with 941 actuators, and an AO system based on stochastic parallel gradient descent optimization with four deformable mirrors (75 control channels). This first-time field demonstration of a cascaded AO system achieved considerably improved performance of wavefront phase aberration compensation. Image quality was improved in a repeatable way in the presence of stressing atmospheric conditions obtained by using stars at elevation angles as low as 15 degrees. PMID:19107154

  18. Cascading and combined effects of cognitive deficits and residual symptoms on functional outcome in schizophrenia - A path-analytical approach.

    PubMed

    Bhagyavathi, Haralahalli D; Mehta, Urvakhsh Meherwan; Thirthalli, Jagadisha; Kumar, C Naveen; Kumar, J Keshav; Subbakrishna, D K; Gangadhar, Bangalore N

    2015-09-30

    Understanding the complex relationship among determinants of real-world functioning in schizophrenia patients in remission is important in planning recovery-oriented interventions. We explored two path-analytical models of functioning in schizophrenia. 170 Schizophrenia patients remitted from positive symptoms underwent fairly comprehensive assessments of cognition - neurocognition (NC) and social cognition (SC), residual symptoms - insight, motivation and other negative symptoms, and socio-occupational functioning. We explored (a) a cascading model, where NC predicted functional outcome through its effects on other determinants and (b) a combined model, incorporating additional direct paths from each of the determinants. The combined model, and not the cascading model demonstrated a good fit. Post-hoc trimming of the combined model by elimination of non-significant paths maintained the goodness-of-fit and was retained as the final model. In addition to the direct paths, this final model demonstrated that (a) NC influenced functioning through SC and insight and (b) SC influenced functioning through motivation and negative symptoms. This suggests that NC and SC may influence functional outcome directly, as well as indirectly, via specific impact on insight, and motivation and negative symptoms respectively. PMID:26208988

  19. Pest insect olfaction in an insecticide-contaminated environment: info-disruption or hormesis effect.

    PubMed

    Tricoire-Leignel, Hélène; Thany, Steeve Hervé; Gadenne, Christophe; Anton, Sylvia

    2012-01-01

    Most animals, including pest insects, live in an "odor world" and depend strongly on chemical stimuli to get information on their biotic and abiotic environment. Although integrated pest management strategies including the use of insect growth regulators (IGRs) are increasingly developed, most insect pest treatments rely on neurotoxic chemicals. These molecules are known to disrupt synaptic transmission, affecting therefore sensory systems. The wide-spread use of neurotoxic insecticides and the growing use of IGRs result in residual accumulation of low concentrations in the environment. These insecticide residues could act as an "info-disruptor" by modifying the chemical communication system, and therefore decrease chances of reproduction in target insects. However, residues can also induce a non-expected hormesis effect by enhancing reproduction abilities. Low insecticide doses might thus induce adaptive processes in the olfactory pathway of target insects, favoring the development of resistance. The effect of sublethal doses of insecticides has mainly been studied in beneficial insects such as honeybees. We review here what is known on the effects of sublethal doses of insecticides on the olfactory system of insect pests. PMID:22457653

  20. Pest Insect Olfaction in an Insecticide-Contaminated Environment: Info-Disruption or Hormesis Effect

    PubMed Central

    Tricoire-Leignel, Hélène; Thany, Steeve Hervé; Gadenne, Christophe; Anton, Sylvia

    2012-01-01

    Most animals, including pest insects, live in an “odor world” and depend strongly on chemical stimuli to get information on their biotic and abiotic environment. Although integrated pest management strategies including the use of insect growth regulators (IGRs) are increasingly developed, most insect pest treatments rely on neurotoxic chemicals. These molecules are known to disrupt synaptic transmission, affecting therefore sensory systems. The wide-spread use of neurotoxic insecticides and the growing use of IGRs result in residual accumulation of low concentrations in the environment. These insecticide residues could act as an “info-disruptor” by modifying the chemical communication system, and therefore decrease chances of reproduction in target insects. However, residues can also induce a non-expected hormesis effect by enhancing reproduction abilities. Low insecticide doses might thus induce adaptive processes in the olfactory pathway of target insects, favoring the development of resistance. The effect of sublethal doses of insecticides has mainly been studied in beneficial insects such as honeybees. We review here what is known on the effects of sublethal doses of insecticides on the olfactory system of insect pests. PMID:22457653

  1. Disruption model

    SciTech Connect

    Murray, J.G.; Bronner, G.

    1982-07-01

    Calculations of disruption time and energy dissipation have been obtained by simulating the plasma as an electrical conducting loop that varies in resistivity, current density, major radius. The calculations provide results which are in good agreement with experimental observations. It is believed that this approach allows engineering designs for disruptions to be completed in large tokamaks such as INTOR or FED.

  2. A multifaceted trophic cascade in a detritus-based system: density-, trait-, or processing-chain-mediated effects?

    PubMed Central

    Albeny-Simões, Daniel; Murrell, Ebony G.; Vilela, Evaldo F.; Juliano, Steven A.

    2015-01-01

    We investigated three pathways by which predators on an intermediate trophic level may produce a trophic cascade in detritus-based systems. Predators may increase lower trophic levels (bacteria) by reducing density of bacteriovores, by altering behavior of bacteriovores, and by processing living bacteriovores into carcasses, feces, and dissolved nutrients that are substrates for bacteria. We tested these pathways in laboratory experiments with mosquitoes in water-filled containers. Larval Toxorhynchites rutilus prey on larval Aedes triseriatus, which feed on bacteria. Using containers stocked with oak leaf infusion as a bacterial substrate, we compared bacterial productivity at 7 and 14 days for: prey alone; prey with a predator; and prey with predation cues but no predator. Controls contained no larvae, either with predation cues or without cues. Predation cues in the control treatment increased bacterial abundance at 7 days, but this effect waned by 14 days. Aedes triseriatus larvae reduced bacterial abundance significantly at 14 days. Predator cues and real predation both eliminated the negative effect of A. triseriatus on bacterial abundance. Predation cues reduced survivorship of A. triseriatus larvae at 14 days, however this effect was smaller than the effect of real predation. We further tested effects of residues from predation as cues or as detritus in a second experiment in which A. triseriatus were killed at similar rates by: real predators; mechanical damage without the predator and carcasses left as detritus; or mechanical damage and carcasses removed. No prey larvae were killed in controls. Bacterial productivity was greater with real predation than in all other treatments and greater when prey larvae were killed or killed and removed, than in controls. Thus we find evidence that all three pathways contribute to the trophic cascade from T. rutilus to bacteria in tree hole systems. PMID:25844268

  3. Progestins as endocrine disrupters in aquatic ecosystems: Concentrations, effects and risk assessment.

    PubMed

    Fent, Karl

    2015-11-01

    In aquatic ecosystems, progesterone (P4) and synthetic progestins (gestagens) originate from excretion by humans and livestock. Synthetic progestins are used for contraception and as P4 for medical treatments as well. Despite significant use, their ecotoxicological implications are poorly understood. Only about 50% of the progestins in use have been analyzed for their environmental occurrence and effects in aquatic organisms. Here we critically summarize concentrations and effects of progestins in aquatic systems. P4 and progestins were mostly detected when analyzed for, and they occurred in the low ng/L range in wastewater and surface water. In animal farm waste and runoff, they reached up to several μg/L. P4 and synthetic progestins act through progesterone receptors but they also interact with other steroid hormone receptors. They act on the hypothalamus-pituitary-gonad axis, lead to oocyte maturation in female and sperm motility in male fish. Additionally, other pathways are affected as well, including the circadian rhythm. Effects of P4, mifepristone and eleven synthetic progestins have been studied in fish and a few compounds in frogs and mussels. Environmental risks may be associated with P4, dydrogesterone and medroxyprogesterone acetate, where transcriptional effects were found at highest environmental levels. Reproductive effects occurred at higher levels. However, norethindrone, levonorgestrel and norgestrel compromised reproduction at environmental (ng/L) concentrations. Thus, some of the progestins are very active endocrine disrupters. This review summarizes the current state of the art and highlights risks for fish. Further research is needed into environmental concentrations and effects of non-investigated progestins, unexplored modes of action, and the activity of mixtures of progestins and other steroids to fully assess their environmental risks. PMID:26276056

  4. The AC-Stark Effect in Nitric Oxide Induced by Rapidly Swept Continuous Wave Quantum Cascade Lasers

    SciTech Connect

    Duxbury, Geoffrey; Kelly, James F.; Blake, Thomas A.; Langford, Nigel

    2012-05-07

    A large AC Stark effect has been observed when nitric oxide, at low pressure in a long optical path (100 m) Herriot cell, is subjected to infrared radiation from a rapidly swept, continuous wave infrared quantum cascade laser. As the frequency sweep rate of the laser is increased, an emission signal induced by rapid passage, occurs after the laser frequency has passed through the resonance of a molecular absorption line. At very high sweep rates a laser field-induced splitting of the absorptive part of the signal is observed, due to the AC Stark effect. This splitting is related to the Autler-Townes mixing of the hyperfine transitions, which lie within the lambda doublet components of the transition, under the Doppler broadened envelope.

  5. Influence of thermal barrier effect of grain boundaries on bulk cascades in alpha-zirconium revealed by molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Jin, Yanan; Lai, Wensheng

    2016-03-01

    The effect of grain boundaries (GBs) on bulk cascades in nano-structured alpha-zirconium has been studied by molecular dynamics (MD) simulations. It turns out that the existence of GBs increases the defect productivity in grains, suggesting that the GBs may act as a thermal barrier and postpone the annihilation of defects within grains. Moreover, it is found that the thermal barrier effect of GBs facilitates the shift of symmetric tilt GBs to the grain with higher temperature, and the smaller the tilt angle is, the easier the boundary shift will be. Thus, the influence of GBs on radiation damage in the nano-structured materials comes from the competition between damage increase in grains and defect annihilation at GBs.

  6. Endocrine Disrupting Chemicals in Fish: Developing Exposure Indicators and Predictive Models of Effects Based on Mechanism of Action

    EPA Science Inventory

    In this paper we provide an overview and illustrative results from a large, integrated project that assesses the effects of endocrine-disrupting chemicals (EDCs) on two small fish models, the fathead minnow (Pimephales promelas) and zebrafish (Danio rerio). For this work a syste...

  7. Effects of Response Cards on Disruptive Behavior and Academic Responding during Math Lessons by Fourth-Grade Urban Students

    ERIC Educational Resources Information Center

    Lambert, Michael Charles; Cartledge, Gwendolyn; Heward, William L.; Lo, Ya-yu

    2006-01-01

    The authors evaluated the effects of response cards on the disruptive behavior and academic responding of students in two urban fourth-grade classrooms. Two conditions, single-student responding and write-on response cards, were alternated in an ABAB design. During single-student responding, the teacher called on one student who had raised his or…

  8. Addressing Disruptive Behaviors in an after School Program Classroom: The Effects of the Daily Behavior Report Card

    ERIC Educational Resources Information Center

    McCorvey, Zamecia J.

    2013-01-01

    There is a need to address behavior discipline problems in special and general education setting classrooms. Disruptive behaviors are a major concern as they create excessive stress and demands for classroom teachers and school administrators to address them. Effective interventions are needed to properly address them. Moreover, classroom…

  9. Effects of endocrine disrupters on the expression of growth hormone and prolactin mRNA in the rainbow trout pituitary.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is now widely accepted that chemical pollutants in the environment can interfere with the endocrine system of animals, thus affecting development and reproduction. Some of these endocrine disrupters (EDs) can have estrogenic or antiestrogenic effects. Most studies to date have focused on the ef...

  10. A Single-Subject Meta-Analysis of the Effectiveness of Time-Out in Reducing Disruptive Classroom Behavior

    ERIC Educational Resources Information Center

    Vegas, Kristopher C.; Jenson, William R.; Kircher, John C.

    2007-01-01

    One current area of dispute in the psychological literature is the inclusion of and proper meta-analytic data analysis procedures for single-subject designs. The current single-subject meta-analysis (N = 25) investigated the effect of time-out for the reduction of disruptive classroom behaviors in nondevelopmentally delayed children. Two separate…