Exposure Trials Research Articles

Relating cold tolerance to winterkill for spotted seatrout at its northern latitudinal limits

In the absence of winter thermal refugia, acute cold stress can lead to episodic mass mortality (winterkill) in fishes. Populations existing near the northern extent of a species' latitudinal range, such as spotted seatrout, Cynoscion nebulosus (Cuvier, 1830), in North Carolina, USA, are particularly vulnerable to winterkill. Information on cold tolerance for spotted seatrout is incomplete, which limits understanding of a likely important source of natural mortality for this species. In this study, two laboratory experiments for controlled exposure of spotted seatrout to dynamic decreases in water temperature were conducted in order to determine cold tolerance as affected by either rapid or prolonged exposure to low-temperature extremes across upper- (10) and lower-estuarine (30) salinities. Under rapid exposure, spotted seatrout were unable to maintain equilibrium at temperatures ≤4°C, with a small but measured mitigating effect of high salinity on the onset of observed physiological stress. No fish survived prolonged exposure (2d) to 3°C but spotted seatrout were tolerant of exposures to 5°C for approximately 5d, after which survival precipitously declined. Survival after 10-d exposure to 7°C was high but not absolute. Salinity had no measured effect on mortality rates in the prolonged exposure trials. These empirical estimates of low-temperature thresholds, along with previously determined field estimates of instantaneous winter natural mortality rate (M), were used to develop models for predicting M. Historic daily water temperatures were used to estimate winter M of spotted seatrout from 1994 to 2015. Predictions of M suggest winterkill (≥50% population loss) in eight of the last 22years; these years correspond to anecdotal and fishery-independent observations of winterkill events in North Carolina. The results of this study provide strong evidence for thermally-limited overwinter survival of spotted seatrout at its northern latitudinal limits, where winterkill events can have population-level impacts.

Addressing Dropout From Prolonged Exposure: Feasibility of Involving Peers During Exposure Trials

Posttraumatic stress disorder (PTSD) is a significant problem for combat veterans. Fortunately, effective treatments, such as Prolonged Exposure (PE), are available and widely disseminated in the Veterans Affairs (VA) health-care system. Nonetheless, despite well-documented effectiveness, attrition remains high at approximately 30% across evidence-based interventions. Early studies indicated that dropout was largely related to stigma and logistical barriers (e.g., travel time and cost). However, research demonstrates that eliminating these logistical and stigma-based barriers (e.g., through home-based telemedicine) has little effect on dropout. We surveyed 82 veterans who dropped out of PE treatment regarding reasons for leaving treatment. Approximately half indicated that in vivo homework assignments caused significant problems, and when asked to consider the possibility of peer support during in vivo exposure assignments, 52% indicated that they would consider returning to treatment with such assistance. In response to this feedback, we constructed an in vivo therapy peer support program wherein peers are directly involved with in vivo exposure exercises. The following brief report presents the rationale for, outline of, and initial feasibility data supporting this program to enhance both return to, and completion of, exposure therapy treatment for PTSD.

Investigation of glyme additives to metalorganic ink systems

Printing of metal oxides at low temperatures is highly challenging, and highly reactive metalorganic inks have been investigated to achieve the target material using process conditions below 150 °C. Unfortunately, their reactivity prohibits facile handling along with making treatment with water to form sol–gels impossible to control and so glyme additives have been investigated to reduce sensitivity without compromising printed material conversion to metal oxide. In this paper, we report addition of a range of glymes to ink formulations and an assessment of the stability enhancement achieved through a range of exposure trials. A clear improvement in air/moisture stability is demonstrated in all cases. Evaluation of the thermal requirements to remove an organic material with and without the additives has been performed with diglyme, proving to be the optimum stabilisation agent leading to minimal change in the process conditions required. Further studies with additional metal doping is planned to enable transparent conducting coatings to be fabricated at low temperatures on flexible plastic substrates.

Exposure to chlorantraniliprole affects the energy metabolism of the caddisfly Sericostoma vittatum.

Caddisflies have been included in ecotoxicological studies because of their sensitivity and ecological relevance. The present study aimed to assess the sublethal effects of an anthranilic diamide insecticide, chlorantraniliprole (CAP), to Sericostoma vittatum. Used worldwide, CAP is a persistent compound that has been found in surface waters at concentrations from 0.1 μg/L to 9.7 μg/L. It targets the ryanodine receptors, and the present ecotoxicological assessment focused on biomarkers related to neurotransmission, biotransformation, oxidative stress damage, and endpoints related to energy processing (feeding, energy reserves, and cellular metabolism). Six days of exposure trials revealed that feeding activity was significantly decreased in S. vittatum larvae exposed to 0.9 μg/L CAP. Concomitantly, a reduction in cellular metabolism and a significant decrease in protein content were also observed in caddisfly larvae exposed to CAP, suggesting metabolic depression. The results show that sublethal concentrations of CAP can cause detrimental sublethal effects on S. vittatum total glutathione content at concentrations as low as 0.2 μg/L. Bioenergetics can be used to assess physiological effects of contaminants, and the present results show that exposure to low, environmentally relevant, concentrations of CAP alter energy acquisition and metabolism in nontarget aquatic insects with potential population level effects. Environ Toxicol Chem 2017;36:1584-1591. © 2016 SETAC.

Focus-of-attention behavioral experiment: an examination of a therapeutic procedure to reduce social anxiety

A clinical protocol based on contemporary cognitive behavioral treatment for social anxiety was developed and examined. Previously published instructions for conducting a focus-of-attention behavioral experiment targeting self-focused attention and safety behaviors during exposure were used to create a structured protocol. Individuals (n = 45) with high levels of social anxiety and public-speaking anxiety were randomly assigned to either a focus-of-attention behavioral experiment (FABE) or an Exposure-Only Control (EOC) condition. During four exposure trials, those in the FABE condition (n = 24) were alternately instructed to engage in self-focused attention vs. externally focused attention and to eliminate safety behaviors. Those in the EOC condition (n = 21) were not so instructed. At post-intervention, individuals in the FABE condition showed significantly less self-focused attention and anxiety, and better observed performance as rated by audience members. Focus-of-attention statistically mediated the effect of condition on anxiety. For those in the FABE condition, the degree of association between focus-of-attention and anxiety during the intervention predicted less self-focused attention post-intervention. The FABE appears to be a useful procedure for implementing part of the contemporary cognitive behavioral treatment model.

Behavioral responses of Arctica islandica (Bivalvia: Arcticidae) to simulated leakages of carbon dioxide from sub-sea geological storage

Sub-sea geological storage of carbon dioxide (CO2) provides a viable option for the Carbon Capture and Storage (CCS) approach for reducing atmospheric emissions of this greenhouse gas. Although generally considered to offer a low risk of major leakage, it remains relevant to establish the possible consequences for marine organisms that live in or on sediments overlying these storage areas if such an event may occur. The present study has used a series of laboratory exposures and behavioral bioassays to establish the sensitivity of Arctica islandica to simulated leakages of CO2. This long-lived bivalve mollusc is widely distributed throughout the North Sea, an area where geological storage is currently taking place and where there are plans to expand this operation significantly. A recently published model has predicted a maximum drop of 1.9pH units in seawater at the point source of a substantial escape of CO2 from sub-sea geological storage in this region. Valve movements of A. islandica exposed to reduced pH seawater were recorded continuously using Hall effect proximity sensors. Valve movement regulation is important for optimising the flow of water over the gills, which supplies food and facilitates respiration. A stepwise reduction in seawater pH showed an initial increase in both the rate and extent of valve movements in the majority of individuals tested when pH fell to 6.2 units. Exposing A. islandica to pH 6.2 seawater continuously for seven days resulted in a clear increase in valve movements during the first 40h of exposure, followed by a gradual reduction in activity intensity over the subsequent five days, suggesting acclimation. The ability of both exposed and control bivalves to burrow successfully into sediment on completion of this exposure was very similar. A final exposure trial, testing whether increased valve movements initiated by reduced pH were related to foot extension during attempted burrowing, found no such association. In summary, significant changes in valve behavior did not occur until seawater pH fell to 6.2 units. The response took the form of an increase in valve activity rather than closure. The absence of foot extension coincident with increased valve movements indicates A. islandica were not attempting to burrow, leaving the possibility that valve movements are supporting a respiratory response to hypercapnia. In conclusion, A. islandica appears to be tolerant of reductions in seawater pH equivalent to those predicted for substantial losses of CO2 through leakage from sub-sea geological storage.

Identification of factors influencing teat dip efficacy trial results by meta-analysis.

Two meta-analyses were conducted using data from peer-reviewed natural exposure (NE) and experimental challenge (EC) teat dip efficacy trials to identify factors influencing the new intramammary infection (IMI) rate. A NE data set containing 16 studies and an EC data set containing 21 studies were created. New IMI rate was calculated based on the percentage of new quarter infections per month (PNQI/mo) for each observation, in both data sets, and used as the dependent variable for model derivation. A linear, mixed-effects model with a random study effect, weighted by number of quarters eligible for infection, was derived for each data set. The final NE model included the effects of experimental design (split herd or split udder), mastitis pathogen group (Staphylococcus aureus, Streptococcus agalactiae, environmental streptococci, gram-negative species, Corynebacterium spp., or coagulase-negative staphylococci), postmilking treatment (iodine, chlorhexidine, linear dodecyl benzene sulfonic acid, chlorine compounds, phenol compounds, or undipped negative controls), and the interaction between mastitis pathogen group and postmilking treatment. Overall, Corynebacterium spp. had the highest new IMI rate (0.0139±0.0018 PNQI/mo), and environmental streptococci and gram-negative species had the lowest (0.0023±0.0022 PNQI/mo). Additionally, trials utilizing a split herd experimental design had a 2-fold higher new IMI rate than trials using a split udder design. The final EC model included the effects of mastitis pathogen (Staph. aureus and Strep. agalactiae), postmilking treatment (iodine, chlorine compounds, "other" active ingredients, or undipped negative controls), geographic region of study (Eastern, Southern, and Pacific Northwest), and the 2-way interactions of region and pathogen group and postmilking treatment and pathogen group. Overall, Staph. aureus and Strep. agalactiae had similar new IMI rates. Quarters dipped postmilking in either iodine (0.0127±0.0099 PNQI/mo), chlorine compounds (0.0258±0.0095 PNQI/mo), or "other" active ingredient teat dips (0.0263±0.0106 PNQI/mo) had lower new IMI rates than undipped quarters (0.0859±0.0087 PNQI/mo). These results indicate that experimental design influences the new IMI rate of teat dip efficacy trials and that using an effective postmilking teat dip has a greater effect on controlling the new Staph. aureus and Strep. agalactiae IMI rate than the teat dip's active ingredient.

Extinction theory & anorexia nervosa: Deepening therapeutic mechanisms

By virtue of adopting the core symptomatic fear (i.e., a fear of weight gain) as a primary treatment target, the treatment of AN centrally involves exposure-driven processes. However, exposure trials targeting the fear of weight gain in AN have been sparse, yielding mixed results to date. In translating extinction theory to the treatment of AN, it is likely that the absence of a clear distinction between what constitutes the core feared cue and the core feared outcome has stymied the application of exposure treatments in AN. This review considers several configurations of the core fear association in AN, noting distinct therapeutic strategies which may allow for more precise efforts in violating fear-based expectancies. Specific guidance is offered in the clinical decision making process as to which strategies might best promote inhibitory learning, and a clinical case is discussed, in which treatment was adjusted to specifically violate the core underlying fear association.

Cathodic delamination at the polymer-to-metal interface of sea cable connector assemblies

Electrical and fibre-optic cable connector assemblies are often required to operate under the very harsh environmental conditions experienced in the offshore oil and gas industry and on ships, autonomous underwater vehicles and remotely operated systems. These assemblies are frequently the source of failure and so must be sealed, mostly at the metal connector-to-cable interface. This is normally achieved using a polyurethane (PU) encapsulant system that bonds at the interface between the metal connector back shell and the cable. In environments where sacrificial anodes are used, however, cable connector assemblies are prone to cathodic delamination (CD, oxygen reduction increasing OH– concentration at the PU/metal interface), which can compromise PU-to-metal bonds causing failure. Materials that are resistant to CD failure are therefore highly desirable. New EC REACH legislation has further regulated the use of hazardous chemicals in the production and use of polymers. New, compliant materials have emerged, although lack well-established performance testing. Hence, in this work, stainless steel 316L, bronze CW451K, titanium Ti6Al4V, PU and commercially available primers (PR24 and PR91) were used to investigate CD failures in cable connector assemblies and galvanic coupling effects. Data obtained from long-term sea raft exposure trials and flowing natural sea water tank tests were used, for the first time, to validate short-term accelerated laboratory salt-spray testing of these materials. The failure rate due to CD was observed to decrease in the order: electrochemical potential > polymeric system > metal substrate, strongly suggesting that electrochemical potential has the most dominant effect on CD failure rates.

Affective lability predicts decreased habituation in posttraumatic stress symptom responding during a single laboratory session of imaginal exposure

Affective lability, or the instability of emotional states, is associated with heightened levels of trauma-related emotional responding and posttraumatic stress disorder (PTSD) symptoms. However, the impact of affective lability, specifically on habituation to idiographic trauma cues, has yet to be examined among trauma-exposed individuals. The current study examined differential response trajectories to trauma-related imaginal exposure as a function of affective lability. Specifically, 72 women with a history of sexual victimization participated in a laboratory-based study involving a single session of repeated imaginal exposures to idiographic traumatic event cues. As hypothesized, participants higher in affective lability reported less reduction in trauma-cue elicited posttraumatic stress symptoms across exposure trials. Given these results, it will be important to continue to extend these laboratory findings to better understand how elevated affective lability is related to response to trauma-focused exposure therapy among individuals with PTSD or other trauma-related psychopathology (e.g., borderline personality disorder).

The design of a legacy indicator tool for measuring climate change related impacts on built heritage

We are experiencing a period of climate change the extent and impact of which is uncertain. In the cultural heritage sector the need for monitoring to inform our understanding is widely agreed, yet there is a lack of consensus over what constitutes ‘monitoring for climate change’. This is due, at least in part, to the extended timescales involved. In this paper the design and implementation of one solution is described; a sustainable legacy indicator tool (LegIT) for the long term tracking of surface weathering effects on built heritage. The assessment of climate change impacts requires 30–100 years of data collection, equal to the period referred to as the ‘climate norm’ by meteorologists. The LegIT is a sacrificial stone object that registers changes in the severity and/or magnitude of weathering patterns on built surfaces, providing a legacy data source for future decision makers. To ensure its sustainability, careful thought was given to the choice of materials, data retrieval and archiving. The tool aims to track surface changes caused by recession, salt crystallisation and microbiological growth. The development and installation of the LegIT is the first long-term exposure trial to be initiated at heritage sites in Ireland and is intended as a legacy for future researchers.

Disgust and imaginal exposure to memories of sexual trauma: Implications for the treatment of posttraumatic stress.

Emerging evidence identifies disgust as a common and persistent reaction following sexual victimization that is linked to posttraumatic stress disorder (PTSD). Importantly, evidence suggests that compared with fear, disgust may be less responsive to repeated exposure, which may have implications for the treatment of PTSD. The current study sought to fill a gap in the existing literature by examining reductions in sexual trauma cue-elicited disgust and anxiety upon repeated imaginal exposure. Seventy-two women with a history of sexual victimization completed a single laboratory-based session that involved repeated imaginal exposure to idiographic disgust- and fear-focused sexual trauma scripts. Results demonstrated that although anxiety and disgust declined at similar rates across exposure trials (t = -.24, p = .81), ratings of disgust (B0 = 61.93) were elevated compared with ratings of anxiety at initiation (B0 = 51.03; t = 4.49, p < .001) of exposure even when accounting for severity of PTSD symptoms. Moreover, change in disgust significantly predicted improvement in script-elicited PTSD symptoms across the course of exposure for individuals exhibiting significant decline in anxiety (B = .006, t = 2.00, p = .048). Change in script-elicited PTSD symptoms was minimal (and was not predicted by the decline in disgust) for individuals exhibiting less change in anxiety (B = -.002, t = -0.46, p = .65). These results add to an increasing literature documenting the importance of disgust in the development, maintenance, and treatment of sexual-trauma-related PTSD. (PsycINFO Database Record

Service life prediction of RC structures in marine environment using long term chloride ingress data: Comparison between exposure trials and real structure surveys

The service life of reinforced concrete (RC) structures in marine environments is mainly influenced by the chloride-induced corrosion of reinforcement, and the development of chloride penetration model is essential for its assessment. The empirical Fick’s second law of diffusion provides a simple way to predict the chloride penetration in practical situations. However, the derivation of parameters of this model is mainly based on the results of laboratory experiments or field exposure trials, and these parameters need to be calibrated with long-term field results of real structures. The filed investigations of seventeen high-pile wharf structures located at the south coast of China were carried out, and the results were compared with the long-term exposure test results in terms of chloride ingress profile. The probability models for surface chloride content and chloride diffusion coefficient were derived according to these results; and finally the effects of different models of chloride ingress parameters, based on exposure trails or based on real structure surveys, on the expected service life of marine structures were investigated.

Infants' generalizations about other people's emotions: Foundations for trait-like attributions.

Adults often attribute internal dispositions to other people and down-play situational factors as explanations of behavior. A few studies have addressed the origins of this proclivity, but none has examined emotions, which rank among the more important dispositions that we attribute to others. Two experiments (N = 270) explored 15-month-old infants' predictive generalizations about other people's emotions. In exposure trials, infants watched an adult (Experimenter) perform actions on a series of objects and observed another adult (Emoter) react with either anger or neutral affect. Infants were then handed the objects to test whether they would imitate the Experimenter's actions. One chief novelty of the study was the inclusion of a generalization trial, in which the Experimenter performed a novel act on a novel object. We systematically manipulated whether the Emoter did or did not respond angrily to this novel demonstration, and whether the Emoter watched the infant's response. Even when no further emotional information was presented in the generalization trial, infants were still hesitant to perform the act when the previously angry Emoter was watching them. Infants tracked the Emoter's affective behavior and, based on her emotional history, they predicted that she would become angry again if she saw them perform a novel act. Making predictive generalizations of this type may be a precursor to more mature trait-like attributions about another person's emotional dispositions.

The interactive effects of microcystin-LR and cylindrospermopsin on the growth rate of the freshwater algae Chlorella vulgaris.

Microcystin-LR (MC-LR) and cylindrospermopsin (CYN) are the most representative cyanobacterial cyanotoxins. They have been simultaneously detected in aquatic systems, but their combined ecotoxicological effects to aquatic organisms, especially microalgae, is unknown. In this study, we examined the effects of these cyanotoxins individually and as a binary mixture on the growth rate of the freshwater algae Chlorella vulgaris. Using the MIXTOX tool, the reference model concentration addition (CA) was selected to evaluate the combined effects of MC-LR and CYN on the growth of the freshwater green algae due to its conservative prediction of mixture effect for putative similar or dissimilar acting chemicals. Deviations from the CA model such as synergism/antagonism, dose-ratio and dose-level dependency were also assessed. In single exposures, our results demonstrated that MC-LR and CYN had different impacts on the growth rates of C. vulgaris at the highest tested concentrations, being CYN the most toxic. In the mixture exposure trial, MC-LR and CYN showed a synergistic deviation from the conceptual model CA as the best descriptive model. MC-LR individually was not toxic even at high concentrations (37mgL(-1)); however, the presence of MC-LR at much lower concentrations (0.4-16.7mgL(-1)) increased the CYN toxicity. From these results, the combined exposure of MC-LR and CYN should be considered for risk assessment of mixtures as the toxicity may be underestimated when looking only at the single cyanotoxins and not their combination. This study also represents an important step to understand the interactions among MC-LR and CYN detected previously in aquatic systems.

Influence of different tropical stress conditions on biochemical parameters invarious broiler strains

The present experiment was conducted to study the effect of different tropical stress conditions on biochemical traits in various broiler strains during 3 to 4 weeks of age. Introgressing some important major genes likes Naked neck (Na) and Frizzle (F) into broiler germplasm may substantially improve the heat tolerance. Hence, the experiment was designed to evaluate three indigenously developed broilers &lt;italic&gt;viz&lt;/italic&gt;. CARIBRO-Tropicana (Naked neck and Frizzle gene bearing), CARIBRO-Mritunjai (Naked neck gene bearing) and CARIBRO-Vishal (Normal plumaged) under different THI (i.e. 72, 85 and 91) for 4 hours daily for 7 days. Total 324 broiler chicks (i.e. 36 chicks in each group) of 3 weeks of age were used in this study. The changes in blood biochemical parameters (i.e. Na, K, Glucose and ACTH) were examined in these experiments at 0&lt;sup&gt;th&lt;/sup&gt;, 3&lt;sup&gt;rd&lt;/sup&gt; and &lt;sub&gt;7&lt;/sub&gt;th into exposure trials. The glucose, ACTH were observed lowest in frizzle and highest in normal plumaged birds under different THI. In experiment Na and K were observed higher in Frizzle and lowest in normal plumaged birds under different THI. The CARIBRO-Vishal showed highest stress as compared to other group. Higher the THI more severe was the effect on the traits. During the 7 day of exposure trial, birds of all the genetic group exhibited the phenomenon of acclimatization as reveled by the averages of various traits at different days into the exposure.

Deterioration of imported timber by marine borers along Visakhapatnam tropical harbour, India

For some time now, timber has been relegated to the back stage due to competition from modern alternatives. Yet, this lone renewable structural material is all set to stage a comeback soon because of the carbon benefits accruing from its use. Although India is blessed with over 4000 woody plant species, the country is timber deficient. In order to bridge the gap between supplies and demand, timber from different countries is being imported. But the performance of such timbers under various service conditions in different Indian environments is not known. Since information on these lines is desirable to put any timber to its best end-use, evaluation of the bioresistance of some of the imported timbers in marine regime was included in a larger programme and the results of this marine component are presented in this paper. A total of twenty timbers that originated from eleven countries together with two Indian timbers were subjected to marine exposure trial in Visakhapatnam tropical waters. The trial followed by data analysis distinguished the twenty imported timbers into five groups, viz., A. pseudoplatanus and Fagus sylvatica from Belgium with 8 months durability; A. pseudoplatanus, Fagus grandifolia, F. sylvatica and Fraxinus angustifolia from France and Havea brasiliensis from India with 9 months longevity; Fraxinus excelsior (Belgium) and Quercus robur (France) with 10 months life; Michelia champaka (India) and Shorea macroptera (Malaysia) with 14 months longevity and Dryobalanops aromatica (Malaysia), Pteocarpus soyauxii (Africa and Cameroon), Shorea s (Indonesia), Shorea robusta (Malaysia), Tectona grandis (Australia, Burma, Ghana, Ivory coast and Tanzania) and Xylia dolabriformis (Burma) with 18 months durability. Compared to the natural resistance of fifty-eight Indian timbers assessed earlier by various workers in the same harbour, performance of the twenty imported timbers tested now is considered as only moderate. While European timbers are advised to be used as marine structural components not in contact with sea water, others may be used universally in all marine applications. However, all the twenty imported timbers had exhibited inferior durability than Dalbergia sisoo, Diospyros melanoxylon, Kingiodendron pinnatum, Lagerstroemia hypoleuca, Lagerstroemia parviflora, Mimusops littoralis, Pterocarpus dalbergioides, Pterocarpus marsupium, Schleichera oleosa, S. robusta, Terminalia arjuna and Terminalia paniculata.

Variation in behavioural plasticity regulates consistent individual differences in Enallagma damselfly larvae

Plastic behavioural responses by individuals to different conditions and consistent individual differences in mean behaviour across situations both contribute to variation in a population. The relationship between behavioural plasticity and consistent individual differences is not clearly understood but may help predict personality variation in animals. High variation in mean behaviour and low variation in individual plastic responses will tend to maintain the rank order of individuals across situations and so permit consistent individual differences. Conversely, low variation in mean behaviour and high variation in plastic responses, by changing the rank orders of individuals, will erode consistent individual differences. Thus, selection that reduces variation in individual plastic responses should increase the opportunity for consistent individual differences in a population. We tested for relationships between heterogeneous predation regimes, the mean and variance of behavioural plasticity and consistent individual differences among three species groups of larval damselflies. Larvae of Enallagma signatum probably face consistent predation from fish over successive generations, whereas Enallagma ebrium/hageni and Enallagma annexum/boreale face a changing predation regime over generations either from fish or larval dragonflies. The behavioural reaction norms of larvae in repeated exposure trials to cues from a predatory fish, dragonfly larvae or no predator differed between species groups. Enallagma ebrium/hageni expressed the most consistent plastic response to predator cues, less variability in plasticity and greater consistent individual differences across cues compared to more variable plastic responses and low consistent individual differences in E. signatum. Selection on behavioural plasticity may enhance consistent individual differences in E. ebrium/hageni whereas relaxing selection on plasticity may reduce consistent individual differences in E. signatum. More generally, selection on plastic behaviour may enhance behavioural types while selection on mean behaviour may reduce behavioural types in animal populations.

Impact of Exposure to Electronic Cigarette Advertising on Susceptibility and Trial of Electronic Cigarettes and Cigarettes in US Young Adults: A Randomized Controlled Trial.

This study assessed the impact of brief exposure to four electronic cigarette (e-cigarette) print advertisements (ads) on perceptions, intention, and subsequent use of e-cigarettes and cigarettes in US young adults. A randomized controlled trial was conducted in a national sample of young adults from an online panel survey in 2013. Participants were randomized to ad exposure or control. Curiosity, intentions, and perceptions regarding e-cigarettes were assessed post-exposure and e-cigarette and cigarette use at 6-month follow-up. Analyses were conducted in 2014. Approximately 6% of young adults who had never used an e-cigarette at baseline tried an e-cigarette at 6-month follow-up, half of whom were current cigarette smokers at baseline. Compared to the control group, ad exposure was associated with greater curiosity to try an e-cigarette (18.3% exposed vs. 11.3% unexposed, AOR = 1.63, 95% CI = 1.18, 2.26) among never e-cigarette users and greater likelihood of e-cigarette trial at follow-up (3.6% exposed vs. 1.2% unexposed, AOR = 2.85; 95% CI = 1.07, 7.61) among never users of cigarettes and e-cigarettes. Exploratory analyses did not find an association between ad exposure and cigarette trial or past 30-day use among never users, nor cigarette use among smokers over time. Curiosity mediated the relationship between ad exposure and e-cigarette trial among e-cigarette never users. Exposure to e-cigarette ads may enhance curiosity and limited trial of e-cigarettes in never users. Future studies are needed to examine the net effect of curiosity and trial of e-cigarettes on longer-term patterns of tobacco use. This randomized trial provides the first evidence of the effect of e-cigarette advertising on a behavioral outcome in young adults. Compared to the control group, ad exposure was associated with greater curiosity to try an e-cigarette among never e-cigarette users and greater likelihood of e-cigarette trial at follow-up in a small number of never e-cigarette users and greater likelihood of e-cigarette trial at follow-up among never users of cigarettes and e-cigarettes.

Changes of lead speciation and microbial toxicity in soil treated with repeated Pb exposure in the presence of BDE209.

Lead (Pb) and decabromodiphenyl ether (BDE209) are main pollutants at electric waste (e-waste) recycling sites (EWRSs), and their joint toxicological effects have received extensive attention. Frequently, soil pollution at EWRSs usually results from the occurrence of repeated single or multiple pollution events, with continuous impacts on soil microorganisms. Therefore, a laboratory incubation study was conducted to determine Pb bioavailability and microbial toxicity in repeated Pb-polluted soil in the presence of BDE209 for the first time. We evaluated the impacts of repetitive exposure trials on chemical fractions of Pb, and the results showed that repeated single Pb pollution event resulted in an increase of carbonates fraction of Pb, which was different from one-off single Pb exposure. Moreover, one-off Pb-treated groups exhibited higher I R (reduced partition index) values on day 30 and all treatments remained the same I R level at the end of incubation period. The parameters of microbial toxicity were well reflected by soil enzymes. During the entire incubation, the dehydrogenase and urease activities were significantly inhibited by Pb (P < 0.01), and BDE209 supply could weaken the adverse influence. Additionally, significant correlations between available or metastable Pb and the two soil enzymes were clearly observed (P < 0.05 or 0.01). Such observations would provide useful information for ecological effects of Pb and BDE209 at EWRSs.