Derived generalization of attentional bias for laboratory-induced threat: Yes but.

There is laboratory evidence that fear conditioning underlies the emergence of attentional bias (AB) for threat. Our main objective was to test, for the first time, whether derived or symbolic responding contributes to the generalization of AB across non-conditioned stimuli. Participants were all university students (N = 86) with no pre-existing conditions. We first employed an exogenous cueing paradigm with two color slides (i.e., A1 or to-be CS+, and A2 or to-be CS-) serving as cues, and loud white noise serving as unconditioned stimulus during conditioning trials. We then employed a match-to-sample procedure to establish a derived equivalence relation between color A1 and arbitrary shape C1 as well as between color A2 and arbitrary shape C2. Next, we investigated the transfer of AB across non-conditioned stimuli: participants performed the same spatial cueing task with non-conditioned C1 and C2 stimuli serving as cues. Results replicated previous findings on the conditioning basis of AB, and most importantly, showed preliminary evidence of AB transfer: those participants who appraised C1 and not C2 as a signal of impending noise showed AB toward C1. This is the first laboratory demonstration that AB may generalize to stimuli physically unrelated to directly conditioned threats. Unfortunately, the small number of participants showing this effect calls for cautious considerations.

Pesticide degradation and export losses at the catchment scale: Insights from compound-specific isotope analysis (CSIA).

Although pesticides undergo degradation tests prior to use, determining their export, degradation and persistence under field conditions remains a challenge for water resource management. Compound specific isotope analysis (CSIA) can provide evidence of contaminant degradation extent, as it is generally independent of non-destructive dissipation (e.g., dilution, sorption, volatilization) regulating environmental concentrations. While this approach has been successfully implemented in subsurface environments, its application to pesticides in near-surface hydrological contexts at catchment scale is lacking. This study demonstrates the applicability of CSIA to track pesticide degradation and export at catchment scale and identify pesticide source areas contributing to changes in stable isotope signature in stream discharge under dynamic hydrological contexts. Based on maximum shifts in carbon stable isotope signatures (Δδ13C  = 4.6 ± 0.5‰) of S-metolachlor (S-met), a widely used herbicide, we estimate maximum degradation to have reached 96 ± 3% two months after first application. Maximum shifts in nitrogen isotope signatures were small and inverse (Δδ15N=-1.3±0.6‰) indicating potential secondary isotope effects during degradation. In combination with a mass balance approach including S-met main degradation products, total catchment non-destructive dissipation was estimated to have reached 8 ± 7% of the applied product. Our results show that CSIA can be applied to evaluate natural attenuation of pesticides at catchment scale. By providing a more detailed account of pesticide dissipation and persistence under field conditions we anticipate the contribution of pesticide CSIA to the improvement of regulatory and monitoring strategies.

Fluorescent tracers to evaluate pesticide dissipation and transformation in agricultural soils.

This study evaluates the mobility and dissipation of two organic fluorescent tracers (uranine, UR and sulforhodamine-B, SRB) in soil from an agricultural field. Two plot experiments were conducted for 2.5months in 2012 and 2016 to compare the behavior of reactive fluorescent tracers (UR and SRB) to the chloroacetanilide herbicide S-metolachlor (S-MET) and bromide (BR), used as a traditional conservative tracer. SRB in top soil closely mimicked the gradual recession of S-MET, while BR overrated both top soil mobility and slow leaching of S-MET in the soil column. In contrast, UR quickly receded in the soil and was entirely dissipated at the end of the study periods. Instead, a strong fluorescent signal that was stable against acidification, and non-traceable in background samples, gradually developed at an excitation wavelength of 510nm in samples from the uppermost soil layer starting 40 (2012) and 22 (2016) days after tracer application. We hypothesize that (bio-)chemical transformation of UR accelerated tracer loss with concomitant formation of the specific transformation product TP510. By LC-MS/MS analysis we propose a probable molecular structure of TP510 and sulfonation as one likely transformation process. Overall, we anticipate our results to be a starting point to use fluorescent tracers in longer term (>2months) agricultural soil studies as a proxy for S-MET and possibly also other organic pesticides, as they are non-conservative in unsaturated soil and may follow similar dissipation and transformation patterns. At the same time their analysis is less costly and they pose smaller environmental risks.

Impact of rainfall patterns and frequency on the export of pesticides and heavy-metals from agricultural soils.

The combined influence of soil characteristics, pollutant aging and rainfall patterns on the export of pollutants from topsoils is poorly understood. We used laboratory experiments and parsimonious modeling to evaluate the impact of rainfall characteristics on the ponding and the leaching of a pollutant mixture from topsoils. The mixture included the fungicide metalaxyl, the herbicide S-metolachlor, as well as copper (Cu) and zinc (Zn). Four rainfall patterns, which differed in their durations and intensities, were applied twice successively with a 7days interval on each soil type. To evaluate the influence of soil type and aging, experiments included crop and vineyard soils and two stages of pollutant aging (0 and 10days). The global export of pollutants was significantly controlled by the rainfall duration and frequency (P<0.01). During the first rainfall event, the longest and most intense rainfall pattern yielded the largest export of metalaxyl (44.5±21.5% of the initial mass spiked in the soils), S-metolachlor (8.1±3.1%) and Cu (3.1±0.3%). Soil compaction caused by the first rainfall reduced in the second rainfall the leaching of remaining metalaxyl, S-metolachlor, Cu and Zn by 2.4-, 2.9-, 30- and 50-fold, respectively. In contrast, soil characteristics and aging had less influence on pollutant mass export. The soil type significantly influenced the leaching of Zn, while short-term aging impacted Cu leaching. Our results suggest that rainfall characteristics predominantly control export patterns of metalaxyl and S-metolachlor, in particular when the aging period is short. We anticipate our study to be a starting point for more systematic evaluation of the dissolved pollutant ponding/leaching partitioning and the export of pollutant mixtures from different soil types in relation to rainfall patterns.

Spanish Validation of the Avoidance and Fusion Questionnaire for Youth (AFQ-Y).

Psychological inflexibility (PI) refers to the overarching and nonadaptive avoidance of thoughts and feelings. PI is a transdiagnostic process that is present in numerous psychopathologies, such as anxiety and mood disorders, addictive behaviors, and chronic pain, as presented by American adults and adolescents. Despite the high rates of depression and depressed mood among Spanish and Latino adolescents and the observed relation between PI and adjustment problems at this age, an instrument assessing PI in Spanish-speaking adolescents is lacking. In this study, we assessed the psychometric properties of a Spanish adaptation of the Avoidance and Fusion Questionnaire for Youth with 483 students from Spain (mean age 13.89 years). The Spanish Avoidance and Fusion Questionnaire for Youth proved to be a two-factor psychometrically sound instrument. Total PI scores correlated positively with depression and negatively with satisfaction with life. The predictive validity results showed cognitive fusion and experiential avoidance to be two interrelated but distinct processes that characterize PI.