Untangling the complex food webs of tropical rainforest streams.

Food webs depict the tangled web of trophic interactions associated with the functioning of an ecosystem. Understanding the mechanisms providing stability to these food webs is therefore vital for conservation efforts and the management of natural systems. Here, we first characterised a tropical stream meta-food web and five individual food webs using a Bayesian Hierarchical approach unifying three sources of information (gut content analysis, literature compilation and stable isotope data). With data on population-level biomass and individually measured body mass, we applied a bioenergetic model and assessed food web stability using a Lotka-Volterra system of equations. We then assessed the resilience of the system to individual species extinctions using simulations and investigated the network patterns associated with systems with higher stability. The model resulted in a stable meta-food web with 307 links among the 61 components. At the regional scale, 70% of the total energy flow occurred through a set of 10 taxa with large variation in body masses. The remaining 30% of total energy flow relied on 48 different taxa, supporting a significant dependency on a diverse community. The meta-food web was stable against individual species extinctions, with a higher resilience in food webs harbouring omnivorous fish species able to connect multiple food web compartments via weak, non-specialised interactions. Moreover, these fish species contributed largely to the spatial variation among individual food webs, suggesting that these species could operate as mobile predators connecting different streams and stabilising variability at the regional scale. Our results outline two key mechanisms of food web stability operating in tropical streams: (i) the diversity of species and body masses buffering against random and size-dependent disturbances and (ii) high regional diversity and weak omnivorous interactions of predators buffering against local stochastic variation in species composition. These mechanisms rely on high local and regional biodiversity in tropical streams, which is known to be strongly affected by human impacts. Therefore, an urgent challenge is to understand how the ongoing systematic loss of diversity jeopardises the stability of stream food webs in human-impacted landscapes.

As teias alimentares representam um emaranhado de interações tróficas associadas ao funcionamento de um ecossistema. Compreender os mecanismos que proporcionam estabilidade a estas teias alimentares é, portanto, vital para os esforços de conservação e gestão dos sistemas naturais. Aqui, primeiro caracterizamos uma meta teia alimentar de riachos tropicais e cinco teias alimentares individuais usando uma abordagem hierárquica Bayesiana unificando três fontes de informação (análise de conteúdo estomacal, compilação de literatura, dados de isótopos estáveis). Com dados sobre biomassa em nível populacional e massa corporal medida individualmente, aplicamos um modelo bioenergético e avaliamos a estabilidade da cadeia alimentar usando um sistema de equações Lotka­Volterra. Em seguida, avaliamos a resiliência do sistema às extinções de espécies individuais usando simulações e investigamos os padrões de rede associados a sistemas com maior estabilidade. O modelo resultou em uma meta teia alimentar estável com 307 ligações entre os 61 componentes. Na escala regional, 70% do fluxo total de energia ocorreu através de um conjunto de dez taxa com grande variação nas massas corporais. Os restantes 30% do fluxo total de energia dependiam de 47 taxa diferentes, apoiando uma dependência significativa de uma comunidade diversificada. A meta teia alimentar foi estável contra extinções de espécies individuais, com uma maior resiliência em teias alimentares que abrigam espécies de peixes onívoros capazes de conectar múltiplos compartimentos da teia alimentar através de interações fracas e não especializadas. Além disso, estas espécies de peixes contribuíram amplamente para a variação espacial entre as cadeias alimentares individuais, sugerindo que estas espécies poderiam operar como predadores móveis conectando diferentes riachos e estabilizando a variabilidade à escala regional. Nossos resultados descrevem dois mecanismos principais de estabilidade da cadeia alimentar operando em riachos tropicais: (i) a diversidade de espécies e massas corporais que protegem contra distúrbios aleatórios e dependentes do tamanho (ii) alta diversidade regional e fracas interações onívoras de predadores que protegem contra a variação estocástica local na composição de espécies. Estes mecanismos dependem de uma elevada biodiversidade local e regional em riachos tropicais, que são conhecidos por serem fortemente afetados pelos impactos humanos. Portanto, um desafio urgente é compreender como a contínua perda sistemática de diversidade põe em risco a estabilidade das teias alimentares em paisagens impactadas pelo homem.

Ayahuasca and Dimethyltryptamine Adverse Events and Toxicity Analysis: A Systematic Thematic Review.

The objective of this paper is to conduct a systematic thematic review of adverse events, safety, and toxicity of traditional ayahuasca plant preparations and its main psychoactive alkaloids (dimethyltryptamine [DMT], harmine, harmaline, and tetrahydroharmine), including discussing clinical considerations (within clinical trials or approved settings). A systematic literature search of preclinical, clinical, epidemiological, and pharmacovigilance data (as well as pertinent reviews and case studies) was conducted for articles using the electronic databases of PubMed and Web of Science (to 6 July 2023) and PsycINFO, ClinicalTrials.gov, and Embase (to 21 September 2022) and included articles in English in peer-reviewed journals. Additionally, reference lists were searched. Due to the breadth of the area covered, we presented the relevant data in a thematic format. Our searches revealed 78 relevant articles. Data showed that ayahuasca or DMT is generally safe; however, some adverse human events have been reported. Animal models using higher doses of ayahuasca have shown abortifacient and teratogenic effects. Isolated harmala alkaloid studies have also revealed evidence of potential toxicity at higher doses, which may increase with co-administration with certain medications. Harmaline revealed the most issues in preclinical models. Nevertheless, animal models involving higher-dose synthetic isolates may not necessarily be able to be extrapolated to human use of therapeutic doses of plant-based extracts. Serious adverse effects are rarely reported within healthy populations, indicating an acceptable safety profile for the traditional use of ayahuasca and DMT in controlled settings. Further randomized, controlled trials with judicious blinding, larger samples, and longer duration are needed.

Land-use intensification systematically alters the size structure of aquatic communities in the Neotropics.

Land-use and land-cover transitions can affect biodiversity and ecosystem functioning in a myriad of ways, including how energy is transferred within food-webs. Size spectra (i.e. relationships between body size and biomass or abundance) provide a means to assess how food-webs respond to environmental stressors by depicting how energy is transferred from small to larger organisms. Here, we investigated changes in the size spectrum of aquatic macroinvertebrates along a broad land-use intensification gradient (from Atlantic Forest to mechanized agriculture) in 30 Brazilian streams. We expected to find a steeper size spectrum slope and lower total biomass in more disturbed streams due to higher energetic expenditure in physiologically stressful conditions, which has a disproportionate impact on large individuals. As expected, we found that more disturbed streams had fewer small organisms than pristine forest streams, but, surprisingly, they had shallower size spectrum slopes, which indicates that energy might be transferred more efficiently in disturbed streams. Disturbed streams were also less taxonomically diverse, suggesting that the potentially higher energy transfer in these webs might be channelled via a few efficient trophic links. However, because total biomass was higher in pristine streams, these sites still supported a greater number of larger organisms and longer food chains (i.e. larger size range). Our results indicate that land-use intensification decreases ecosystem stability and enhances vulnerability to population extinctions by reducing the possible energetic pathways while enhancing efficiency between the remaining food-web linkages. Our study represents a step forward in understanding how land-use intensification affects trophic interactions and ecosystem functioning in aquatic systems.

Default Mode Network Modulation by Psychedelics: A Systematic Review.

Psychedelics are a unique class of drug that commonly produce vivid hallucinations as well as profound psychological and mystical experiences. A grouping of interconnected brain regions characterized by increased temporal coherence at rest have been termed the Default Mode Network (DMN). The DMN has been the focus of numerous studies assessing its role in self-referencing, mind wandering, and autobiographical memories. Altered connectivity in the DMN has been associated with a range of neuropsychiatric conditions such as depression, anxiety, post-traumatic stress disorder, attention deficit hyperactive disorder, schizophrenia, and obsessive-compulsive disorder. To date, several studies have investigated how psychedelics modulate this network, but no comprehensive review, to our knowledge, has critically evaluated how major classical psychedelic agents-lysergic acid diethylamide, psilocybin, and ayahuasca-modulate the DMN. Here we present a systematic review of the knowledge base. Across psychedelics there is consistent acute disruption in resting state connectivity within the DMN and increased functional connectivity between canonical resting-state networks. Various models have been proposed to explain the cognitive mechanisms of psychedelics, and in one model DMN modulation is a central axiom. Although the DMN is consistently implicated in psychedelic studies, it is unclear how central the DMN is to the therapeutic potential of classical psychedelic agents. This article aims to provide the field with a comprehensive overview that can propel future research in such a way as to elucidate the neurocognitive mechanisms of psychedelics.

A Non-Clinical Referral Tool to Help Identify Problematic Child Sexual Behavior: Development, Training, and Initial User Feedback.

Early identification of children and youth who engage in problematic sexual behavior is important for all parties involved, such as children who exhibit and are impacted by the behavior. There are several reliable and valid identification tools that can be used to recognize problematic sexual behavior in children and youth (PSB-CY) in clinical practice; however, professionals who work with children in non-clinical settings (i.e., child development centers, youth programs, and schools) often have limited resources and tools when they encounter PSB-CY. This paper describes the development, content, and user feedback of a referral tool (RT) that was designed to help identify incidents of PSB-CY for use with military agencies and schools. Specifically, the RT was designed to help professionals, who may have observed or who may have been made aware of sexual behaviors in children and youth, organize their observations of the behavior in alignment with evidence-based information about PSB-CY and consistently document these occurrences. The RT guides users in determining if the observed behavior is normative, cautionary, or problematic and promotes informed decisions about whether the behavior needs to be referred to those who have experience using clinical tools for further review and the identification of next steps for supporting the children and families involved. Early adopters provided feedback on the use of the RT. The feedback suggested that the tool was user-friendly, understandable, and helpful as they made objective decisions about how to identify and handle referrals of PSB-CY.

Trajectories of functioning in a population-based sample of veterans: contributions of moral injury, PTSD, and depression.

BACKGROUND: Although research has shown that exposure to potentially traumatic and morally injurious events is associated with psychological symptoms among veterans, knowledge regarding functioning impacts remains limited. METHODS: A population-based sample of post-9/11 veterans completed measures of intimate relationship, health, and work functioning at approximately 9, 15, 21, and 27 months after leaving service. Moral injury, posttraumatic stress, and depression were assessed at ~9 months post-separation. We used Latent Growth Mixture Models to identify discrete classes characterized by unique trajectories of change in functioning over time and to examine predictors of class membership. RESULTS: Veterans were assigned to one of four functioning trajectories: high and stable, high and decreasing, moderate and increasing, and moderate and stable. Whereas posttraumatic stress, depression, and moral injury associated with perpetration and betrayal predicted worse outcomes at baseline across multiple functioning domains, moral injury associated with perpetration and depression most reliably predicted assignment to trajectories characterized by relatively poor or declining functioning. CONCLUSIONS: Moral injury contributes to functional problems beyond what is explained by posttraumatic stress and depression, and moral injury due to perpetration and depression most reliably predicted assignment to trajectories characterized by functional impairment over time.

Visitors' Assessment and Utilization of Evidence-Based Program Resources (EBPR) Websites.

Background: Evidence-based program resources (EBPR) websites for behavioral health are a potentially useful tool to assist decision-makers and practitioners in deciding which behavioral health interventions to implement. EBPR websites apply rigorous research standards to assess the effectiveness of behavioral healthcare programs, models, and clinical practices. Method: Visitors to a convenience sample of six EBPR websites (N=369, excluding students) were recruited for telephone interviews primarily by means of a pop-up invitation on the sites. Results: The visitors view the EBPR sites as important sources of information to support the identification and adoption of evidence-based programs/practices (EBPs) in behavioral healthcare, which aligns with the primary mission of EBPRs. For repeat visitors, there was some indication that the information obtained helped effect certain changes in their agencies' programs and policies. However, increased or improved guidance on EBP implementation was also requested. Conclusion: EBPR websites should be better publicized to the behavioral healthcare field.

The interaction of exposure to adverse childhood and combat experiences on the current mental health of new post-9/11 veterans.

Military veterans have greater exposure to adverse childhood experiences (ACEs) than civilians and many also encounter warfare exposures, which can increase the likelihood of mental health problems. The purpose of this study was to test an interaction between childhood traumas and warfare exposures on the mental health of a sample of nearly 10,000 new post-9/11 veterans. Results revealed that male veterans exposed to one or two ACEs, but no warfare, were more likely to experience anxiety, depression, suicidal thinking, and angry outbursts than the reference group (i.e., no ACEs and no warfare exposure). Female veterans exposed to one or two ACEs, but no warfare, were only more likely to experience suicidal thinking. Male and female veterans exposed to three or more ACEs and no warfare were more likely to experience probable posttraumatic stress disorder (PTSD), anxiety, depression, suicidality, and angry outbursts. Among those veterans who experienced corollaries of combat only (e.g., seeing someone killed or seriously wounded), male, but not female veterans were more likely to have probable PTSD, anxiety, and depression. Veterans exposed to warfare (i.e., combat and the corollaries of combat), irrespective of ACEs exposure, were the most likely to report mental health symptoms. Implications for community-based mental health services are discussed.

Development of a US national-scale, mixed-source, pesticide, rural well database for use in drinking water risk assessment: an atrazine case study.

For pesticide registrations in the USA under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as implemented by the United States Environmental Protection Agency, drinking water risk assessments for groundwater sources are based on standard scenario modeling concentration estimates. The conceptual model for the drinking water protection goals is defined in terms of (1) a rural well in or near a relatively high pesticide use area, a shallow well (4-10 m); (2) long-term, single-station weather data; (3) soils characterized as highly leachable; (4) upper-end or surrogate, worst-case environmental fate parameters; and (5) maximum, annual use rates repeated every year. To date, monitoring data have not been quantitatively incorporated into FIFRA drinking water risk assessment; even though considerable, US national-scale temporal and spatial data for some chemistries exists. Investigations into drinking water monitoring data development have historically focused on single-source efforts that may not represent wide geographies and/or time periods, whereas Safe Drinking Water Act groundwater monitoring data are focused on a community-level scale rather than an individual, shallow, rural well. In the current case study, US national-scale, rural well data for the herbicide atrazine was collected, quality controlled, and combined into a single database from mixed sources (termed the atrazine rural well database) to (1) characterize differences between exposure estimates from standard EPA modeling approaches for specific characterization, (2) evaluate monitoring data toward direct use in US drinking water risk assessments to compliment or supersede standard modeling approaches to define risk, and (3) evaluate monitoring trends a function of time relative to label changes implemented as part of the registration review process. Of the 75,665 drinking water samples collected from groundwater, atrazine was only detected in 3185, a 4% detection rate.

The Moral Injury Symptoms Scale-Military Version-Short Form: Further Scale Validation in a U.S. Veteran Sample.

This study assessed the Moral Injury Symptoms Scale - Military Version - Short Form's (MISS-M-SF) factor structure and construct validity. Participants included 3650 combat-deployed U.S. veterans who answered all 10 MISS-M-SF items from the sixth wave of The Veterans Metric Initiative (TVMI). EFA results suggested a two-factor solution, based on item wording, fit best. CFA results indicated a bifactor model (one general factor and two method factors, based on item wording) fit best. Further investigation revealed that a one-factor model could be used despite the data's multidimensionality. Item-level analyses revealed four items represented the general factor exceptionally well, potentially simplifying assessment in research and clinical applications. Construct validity was also demonstrated through moderate to high correlations with conceptually related measures.

Systematic variation in food web body-size structure linked to external subsidies.

The relationship between body mass (M) and size class abundance (N) depicts patterns of community structure and energy flow through food webs. While the general assumption is that M and N scale linearly (on log-log axes), nonlinearity is regularly observed in natural systems, and is theorized to be driven by nonlinear scaling of trophic level (TL) with M resulting in the rapid transfer of energy to consumers in certain size classes. We tested this hypothesis with data from 31 stream food webs. We predicted that allochthonous subsidies higher in the web results in nonlinear M-TL relationships and systematic abundance peaks in macroinvertebrate and fish size classes (latter containing salmonids), that exploit terrestrial plant material and terrestrial invertebrates, respectively. Indeed, both M-N and M-TL significantly deviated from linear relationships and the observed curvature in M-TL scaling was inversely related to that observed in M-N relationships. Systemic peaks in M-N, and troughs in M-TL occurred in size classes dominated by generalist invertebrates, and brown trout. Our study reveals how allochthonous resources entering high in the web systematically shape community size structure and demonstrates the relevance of a generalized metabolic scaling model for understanding patterns of energy transfer in energetically 'open' food webs.

Medicinal psychedelics for mental health and addiction: Advancing research of an emerging paradigm.

The medical use of psychedelic substances (e.g. psilocybin, ayahuasca, lysergic acid diethylamide and 3,4-methylenedioxymethamphetamine) is attracting renewed interest, driven by a pressing need for research and development of novel therapies for psychiatric disorders, as well as promising results of contemporary studies. In this Viewpoint, we reflect upon the 'Clinical Memorandum on Psychedelics' recently released by the Royal Australian and New Zealand College of Psychiatrists and note subsequent developments including the application for down-scheduling of psilocybin and 3,4-methylenedioxymethamphetamine presently being considered by the Therapeutic Goods Administration and approvals for access via the Special Access Scheme. We suggest that this field is worthy of rigorous research to assess potential benefits, address safety parameters and clarify therapeutic mechanisms. To this end, we outline recent research findings, provide an overview of current knowledge relating to mechanisms of action and discuss salient aspects of the psychedelic-assisted psychotherapy treatment model. The sum of this research points towards medicinal psychedelics as a potential new class of psychiatric treatments when used within a medically supervised framework with integrated psychotherapeutic support. However, before widespread translation into clinical use can occur, appropriately designed and sufficiently powered trials are required to detect both potential positive and negative outcomes. Unique safety and regulatory challenges also need to be addressed. As for any new medical therapy, psychedelic research needs to be conducted in a rigorous manner, through the dispassionate lens of scientific enquiry. Carte blanche availability to practitioners, without specific protocols and appropriate training, would be potentially harmful to individuals and detrimental to the field.

The Impact of Discriminatory Stress on Changes in Posttraumatic Stress Severity at the Intersection of Race/Ethnicity and Gender.

Given the diversity of military veterans and growing evidence of ethnoracial disparities in posttraumatic stress disorder (PTSD) within this population, elucidating the role of discrimination-related stress in contributing to these disparities is crucial. We examined the relative impact of discriminatory stress (i.e., due to race/ethnicity, religion, nationality, gender, sexual orientation, or physical appearance) on 6-month changes in PTSD symptom severity among trauma-exposed White (74%), Black (11%) and Hispanic/Latino/a/x (15%) veterans (17% female). PTSD symptoms were measured with the 8-item PTSD Checklist for DSM-5. A measure of the extent to which discrimination has caused stress for the respondent assessed discriminatory stress. Hierarchical regression analyses examined interactions among race/ethnicity, gender and discriminatory stress in predicting six-month changes in PTSD severity. Black and Hispanic/Latino/a/x veterans reported higher baseline PTSD severity and discriminatory stress than White veterans, with some variation by gender. Three-way interactions of race/ethnicity by discriminatory stress by gender were significant, controlling for income, education and age. The relationship between discriminatory stress and increases in PTSD severity was significantly stronger for Black women compared with Black men and did not differ between White men and women. There was also a stronger relationship between discriminatory stress and increases in PTSD severity for Hispanic/Latino/x men as compared to Black men. These findings suggest that discriminatory stress impacts PTSD severity differentially for various ethnoracial/gender groups and highlight the value of applying an intersectional framework that accounts for the synergistic connections among multiple identities to future screening, intervention, and research efforts.

Development of a mixed-source, single pesticide database for use in ecological risk assessment: quality control and data standardization practices.

Inclusion of pesticide monitoring data in pesticide risk assessment is important yet challenging for several reasons, including infrequent or irregular data collection, disparate sources procedures and associated monitoring periods, and interpretation of the data itself in a policy context. These challenges alone, left unaddressed, will likely introduce unintentional and unforeseen risk assessment conclusions. While individual water quality monitoring programs report standard operating procedures and quality control practices for their own data, cross-checking data for duplicated data from one database to another does not routinely occur. Consequently, we developed a novel quality control and assurance methodology to identify errors and duplicated records toward creating an aggregated, single pesticide database toward use in ecological risk assessment. This methodology includes (1) standardization and reformatting practices, (2) data error and duplicate record identification protocols, (3) missing or inconsistent limit of detection and quantification reporting, and (4) site metadata scoring and ranking procedures to flag likely duplicate records. We applied this methodology to develop an aggregated (multiple-source), national-scale database for atrazine from a diverse set of surface water monitoring programs. The resultant database resolved and/or removed approximately 31% of the total ~ 385,000 records that were due to duplicated records. Identification of sample replicates was also developed. While the quality control and assurances methodologies developed in this work were applied to atrazine, they generally demonstrate how a properly constructed and aggregated single pesticide database would benefit from the methods described herein before use in subsequent statistical and data analysis or risk assessment.

Going the Distance: Technical Assistance to Community Prevention Coalitions and its impact on Prevention Coalitions Over Time.

Prevention Coordinators are the linking agents providing technical assistance between universities and communities in the PROSPER model to support the implementation and sustainability of youth and family programs that have reduced substance abuse in prior research. This study examines the outcomes and trajectory of the frequency of contact of technical assistance (i.e. dosage) with community collaborative prevention coalitions across the three stages of coalition development. After communities were randomized, members of PROSPER coalitions (n=12) provided information about the quality of their operations at five time points across four and one-half years; prevention coordinators reported on the frequency of contact with their community coalitions at 14 intervals across the same period of time. This study only utilizes the intervention communities. Results from correlational models show that levels of dosage relate to the quality of internal coalition processes over time, but that the direction of the relationship changes over time: high frequency of contact early on relates to lower coalition-rated functioning initially. In contrast, early frequency of contact relates to higher levels of coalition functioning at later time points. Furthermore, longitudinal mixed models show that levels of dosage were consistent over time. These results provide empirical support of the importance of a proactive technical assistance model and add further evidence that important distinctions exist among different coalition developmental phases.

The Impact of Posttraumatic Stress Disorder and Moral Injury on Women Veterans' Perinatal Outcomes Following Separation From Military Service.

Posttraumatic stress disorder (PTSD) has been found to lead to several adverse perinatal outcomes in the general population. Preliminary research has found that women veterans with PTSD have an increased prevalence of preterm birth, gestational diabetes, and preeclampsia. Less research has examined the role of moral injury (MI) in perinatal outcomes. This longitudinal survey study examined the impact of PTSD symptoms and MI on prospectively assessed adverse perinatal outcomes among women who became pregnant in the first 3 years after separating from U.S. military service (N = 318). The Moral Injury Events Scale was used to assess the degree to which individuals experienced distress related to transgressions of deeply held moral beliefs, and the Primary Care PTSD Screen for DSM-5 (PC-PTSD) was used to assess PTSD symptoms. Perinatal outcomes included experiencing an adverse pregnancy outcome (e.g., preterm birth, gestational diabetes), postpartum depression and/or anxiety, and perceived difficult pregnancy. Although both PTSD symptoms, adjusted odds ratio (aOR) = 1.16, 95% CI [1.00, 1.35]; and MI, aOR = 1.27, 95% CI [1.06, 1.41], emerged as significant predictors of adverse pregnancy outcomes, only PTSD symptoms were a significant predictor of postpartum depression and/or anxiety, aOR = 1.43, 95% CI [1.22, 1.68], and perception of a difficult pregnancy, ß = .31, when controlling for lifetime trauma exposure, age, socioeconomic status, and ethnic/racial minority status. The results indicate that both PTSD symptoms and MI are associated with adverse perinatal outcomes, supporting the potential need to screen for both PTSD and MI during the perinatal period.

Moral Injury and Social Well-Being: A Growth Curve Analysis.

Moral injury (MI) may occur in the context of committing transgressions (i.e., self-directed MI reactions), witnessing transgressions, or being the victims of others' transgressions (i.e., other-directed MI reactions) that violate an individual's moral principles. Veterans with MI may experience impaired social well-being (SWB). Studies on MI and veterans' SWB have focused almost exclusively on social support and used cross-sectional data. The present study used growth curve analyses to examine the associations between self- and other-directed MI reactions and veterans' levels of social support, social functioning, social activities, and social satisfaction over the first 18 to 21 months of their transition to civilian life (N = 9,566). The results demonstrated declines in all SWB outcomes, with self- and other-directed MI reactions having differential effects. Higher versus lower levels of other-directed MI reactions were related to lower baseline scores on all SWB outcomes, ßs = -.06 to -.20, and steeper declines over time in social functioning, ß = -.09, and social satisfaction, ß = -.10. Higher versus lower levels of self-directed MI reactions were related to lower baseline levels of social functioning, ß = -.07, but higher baseline levels of social activity, ß = .04. Higher versus lower levels of self-directed MI reactions were related to a steeper decline in social activity over time, ß = -.10. These findings present a more nuanced picture than that depicted by current MI theoretical frameworks and support further research to uncover moderators of the associations between self- and other-directed MI reactions and SWB outcomes.

Reducing barriers to post-9/11 veterans' use of programs and services as they transition to civilian life.

BACKGROUND: Numerous programs exist to support veterans in their transitions to civilian life. Programs are offered by a host of governmental and non-governmental stakeholders. Veterans report encountering many barriers to program participation. This study identified barrier reduction strategies offered by programs that new post-9/11 veterans reported using, determined which strategies veterans use and value, and examined veteran characteristics that impact their odds of using programs that offer barrier reduction strategies. METHOD: This study reflects findings from the first wave of data collection of The Veterans Metrics Initiative (TVMI), a longitudinal study examining the military-to-civilian reintegration of new post-9/11 veterans. The websites of programs used by respondents were coded for barrier reduction components. Veterans also indicated which barrier reduction components they found most helpful in meeting their reintegration goals. RESULTS: Of 9566 veterans who participated in Wave 1 data collection, 84% reported using a program that offered at least one barrier reduction component. Barrier reduction components included tangible supports (e.g., scholarships, cash), increased access to programs, decreased stigma, and encouraged motivation to change. Although only 4% of programs that were used by veterans focused on helping them obtain Veterans Administration benefits, nearly 60% of veterans reported that this component was helpful in reaching their goals. Access assistance to other resources and supports was also reported as a helpful barrier reduction component. For instance, approximately 20% of veterans nominated programs that offered transportation. The study also found evidence of a misalignment between the kinds of barrier reduction components veterans valued and those which programs offered. Veterans from the most junior enlisted ranks, who are at most risk, were less likely than those from other ranks to use barrier reduction components. Study limitations and ideas for future research are discussed. CONCLUSIONS: Despite the evidence that barrier reduction components enhance access to programs and contribute to program sustainability, many programs used by post-9/11 veterans do not offer them. There was also a misalignment between the barrier reduction strategies that veterans value and the strategies offered by programs. Veteran serving organizations should increasingly implement barrier reduction strategies valued by veterans.

Comparing biotic drivers of litter breakdown across stream compartments.

Litter breakdown in the streambed is an important pathway in organic carbon cycling and energy transfer in the biosphere that is mediated by a wide range of streambed organisms. However, most research on litter breakdown to date has focused on a small fraction of the taxa that drive it (e.g. microbial vs. macroinvertebrate-mediated breakdown) and has been limited to the benthic zone (BZ). Despite the importance of the hyporheic zone (HZ) as a bioreactor, little is known about what, or who, mediates litter breakdown in this compartment and whether breakdown rates differ between the BZ and HZ. Here, we explore the relationship between litter breakdown and the variation in community structure of benthic and hyporheic communities by deploying two standardized bioassays (cotton strips and two types of commercially available tea bags) in 30 UK streams that encompass a range of environmental conditions. Then, we modelled these assays as a response of the streambed compartment and the biological features of the streambed assemblage (Prokaryota, Protozoa and Eumetazoa invertebrates) to understand the generality and efficiency of litter processing across communities. Litter breakdown was much faster in the BZ compared with the HZ (around 5 times higher for cotton strips and 1.5 times faster for the tea leaves). However, differences in litter breakdown between the BZ and the HZ were mediated by the biological features of the benthos and the hyporheos. Biomass of all the studied biotic groups, α-diversity of Eumetazoa invertebrates and metabolic diversity of Prokaryota were important predictors that were positively related to breakdown coefficients demonstrating their importance in the functioning of the streambed ecosystem. Our study uses a novel multimetric bioassay that is able to disentangle the contribution by Prokaryota, Protozoa and Eumetazoa invertebrates to litter breakdown. In doing so, our study reveals new insights into how organic matter decomposition is partitioned across biota and streambed compartments.

Depth and vertical hydrodynamics constrain the size structure of a lowland streambed community.

Abundance-body mass (N-M) relationships are prominent macroecological patterns and provide an integrated measurement of the structure and energy flow through natural communities. However, little is known about how N-M relationships are constrained by local environmental conditions. Here, we quantify how sediment depth and direction of surface-groundwater exchange (vertical hydrodynamics), two major drivers of the streambed ecology, determine N-M scaling in a sandy lowland European stream. Streambed assemblages included flagellates, ciliates, meiofauna and macroinvertebrates, and spanned five orders of magnitude in body mass. We detected a significant interaction of body mass with depth and vertical hydrodynamics with a sharp reduction in N-M slopes in the hyporheic zone and under upwelling conditions. These results revealed that streambed assemblages become more size-structured as environmental constraints increase with direct implications for the metabolic capacity and functioning of the system.