Análise agroecológica de dois paradigmas modernos.

O presente estudo é uma revisão sobre a contribuição da agroecologia para o debate conservacionista e desenvolvimentista. O discurso tradicional da biologia da conservação traz um enfoque exclusivo nas unidades de conservação (UCs), prejudicando os esforços de preservação da matriz paisagística como todo. Por outro lado, o discurso pautado por alguns desenvolvimentistas é levado por uma diferente, mas não menos equivocada, corrente de pensamento que acredita na superioridade da produção agrícola intensiva frente à agricultura familiar. No Brasil, essa modernização precoce da agricultura teve consequências catastróficas para o pequeno produtor bem como levou o aumento da pobreza no campo e nas cidades. Através da crítica agroecológica, ambas as correntes, a conservacionista e a desenvolvimentista, se baseiam em preceitos falaciosos. Tendo em vista essas contradições, o estudo da agroecologia, mais especificamente o estudo dos sistemas agroflorestais diversificados, contribui para a conservação e traz uma maior responsabilidade social para a produção agrícola

Spatial heterogeneity promotes coexistence of rock-paper-scissor metacommunities

The rock-paper-scissor game -- which is characterized by three strategies R,P,S, satisfying the non-transitive relations S excludes P, P excludes R, and R excludes S -- serves as a simple prototype for studying more complex non-transitive systems. For well-mixed systems where interactions result in fitness reductions of the losers exceeding fitness gains of the winners, classical theory predicts that two strategies go extinct. The effects of spatial heterogeneity and dispersal rates on this outcome are analyzed using a general framework for evolutionary games in patchy landscapes. The analysis reveals that coexistence is determined by the rates at which dominant strategies invade a landscape occupied by the subordinate strategy (e.g. rock invades a landscape occupied by scissors) and the rates at which subordinate strategies get excluded in a landscape occupied by the dominant strategy (e.g. scissor gets excluded in a landscape occupied by rock). These invasion and exclusion rates correspond to eigenvalues of the linearized dynamics near single strategy equilibria. Coexistence occurs when the product of the invasion rates exceeds the product of the exclusion rates. Provided there is sufficient spatial variation in payoffs, the analysis identifies a critical dispersal rate $d^*$ required for regional persistence. For dispersal rates below $d^*$, the product of the invasion rates exceed the product of the exclusion rates and the rock-paper-scissor metacommunities persist regionally despite being extinction prone locally. For dispersal rates above $d^*$, the product of the exclusion rates exceed the product of the invasion rates and the strategies are extinction prone. These results highlight the delicate interplay between spatial heterogeneity and dispersal in mediating long-term outcomes for evolutionary games.Comment: 31pages, 5 figure

Controlled Trials in Children: Quantity, Methodological Quality and Descriptive Characteristics of Pediatric Controlled Trials Published 1948-2006

BACKGROUND: The objective of this study was to describe randomized controlled trials (RCTs) and controlled clinical trials (CCTs) in child health published between 1948 and 2006, in terms of quantity, methodological quality, and publication and trial characteristics. We used the Trials Register of the Cochrane Child Health Field for overall trends and a sample from this to explore trial characteristics in more detail. METHODOLOGY/PRINCIPAL FINDINGS: We extracted descriptive data on a random sample of 578 trials. Ninety-six percent of the trials were published in English; the percentage of child-only trials was 90.5%. The most frequent diagnostic categories were infectious diseases (13.2%), behavioural and psychiatric disorders (11.6%), neonatal critical care (11.4%), respiratory disorders (8.9%), non-critical neonatology (7.9%), and anaesthesia (6.5%). There were significantly fewer child-only studies (i.e., more mixed child and adult studies) over time (P = 0.0460). The proportion of RCTs to CCTs increased significantly over time (P<0.0001), as did the proportion of multicentre trials (P = 0.002). Significant increases over time were found in methodological quality (Jadad score) (P<0.0001), the proportion of double-blind studies (P<0.0001), and studies with adequate allocation concealment (P<0.0001). Additionally, we found an improvement in reporting over time: adequate description of withdrawals and losses to follow-up (P<0.0001), sample size calculations (P<0.0001), and intention-to-treat analysis (P<0.0001). However, many trials still do not describe their level of blinding, and allocation concealment was inadequately reported in the majority of studies across the entire time period. The proportion of studies with industry funding decreased slightly over time (P = 0.003), and these studies were more likely to report positive conclusions (P = 0.028). CONCLUSIONS/SIGNIFICANCE: The quantity and quality of pediatric controlled trials has increased over time; however, much work remains to be done, particularly in improving methodological issues around conduct and reporting of trials

Girls\u27 internalizing symptoms and white matter tracts in Cortico-Limbic circuitry

© 2019 The Authors Dysfunction in cortico-limbic circuitry is implicated in internalizing disorders (i.e., depressive and anxious disorders), but less is known about whether structural variations precede frank disorder and thus potentially mark risk. We therefore examined associations between white matter (WM) tract microstructure in cortico-limbic circuitry at age 7 and concurrent and longitudinal patterns of internalizing symptoms in 42 typically developing girls using Diffusion Tensor Imaging (DTI). Girls\u27 internalizing symptoms were concurrently associated with reduced fractional anisotropy (FA) in segments of the cingulum bundle (CB) and the uncinate fasciculus (UF), bilaterally. Moreover, latent profile analysis showed that girls with increasing internalizing symptoms, based on assessments at ages 3, 6, 7, and 8, had reduced FA in these segments compared to girls with stably low symptoms. These results point to a putative neural mechanism underlying the course of childhood internalizing symptoms

Neural activity during self-referential processing in children at risk for depression.

ABSTRACT BACKGROUND: According to cognitive theories of depression, more negative and less positive self-schemas are thought to play a causal role in the disorder. Existing evidence speaks to the neural substrates of self-referential processes in both healthy and depressed individuals, but little is known about how the brain relates to selfreferential processing in the context of depression risk in children. We therefore studied the neural substrates of self-referential processing in never-depressed preadolescent children at high and low risk for depression based on maternal depression history. METHODS: A total of 87 never-depressed 10–12-year-old children (29 with maternal depression) completed a selfreferential encoding task during a functional magnetic resonance imaging session, in which they were presented a series of positive and negative trait adjectives and endorsed whether each word was self-descriptive. Small volume correction analyses were conducted within 7 regions of interest that are important for self-referential and emotion-related processes. RESULTS: Analyses of small volume correction indicated that high-risk children showed greater activation in the ventrolateral prefrontal cortex and ventromedial prefrontal cortex during the positive-word self-referential encoding task condition than low-risk children. Ventrolateral prefrontal cortex activation mediated the association between maternal depression and child depressive symptoms only when children had lower positive self-schemas, indicating that more positive self-schemas may protect at-risk children from developing depressive symptoms. CONCLUSIONS: Cortical midline and prefrontal regions are important to self-, emotion-, and regulation-related processes. Heightened activation within these regions in never-depressed high-risk children indicates that these neurobiological substrate

Fragmenting Forests: The Double Edge of Effective Forest Monitoring

The link between ineffective forest monitoring and forest degradation is well known. Under REDD+, monitoring stands to become more important as a means of maintaining incentive. Little attention however has been paid to the possible adverse consequences of forest monitoring. Our research develops a spatially explicit, agent-based model (ABM) of timber extraction in a Congo Basin forest concession to investigate the potential conservation impact of more effective monitoring. We modeled the building of access roads, and logging of legal timber and illegal timber, where illegal timber may be interpreted broadly to include prohibited species, smaller trees, or trees in areas where cutting is not permitted. We investigated road building under (1) random spot monitoring of logging sites and (2) monitoring of logged trunks at checkpoints. Our findings indicate that although more effective monitoring can reduce illegal harvesting, it can also lead to construction of denser road networks and higher levels of forest fragmentation, with an implied loss of biodiversity. These insights are particularly relevant in the context of REDD+, as they suggest that some monitoring strategies may lead to more forest fragmentation, even as they help reduce emissions

Orbitofrontal cortex grey matter volume is related to children\u27s depressive symptoms

© 2020 The Author(s) Adults with a history of depression show distinct patterns of grey matter volume (GMV) in frontal cortical (e.g., prefrontal cortex, orbitofrontal cortex) and limbic (e.g., anterior cingulate, amygdala, hippocampus, dorsal striatum) structures, regions relevant to the processing and regulation of reward, which is impaired in the context of depression. However, it is unclear whether these GMV associations with depression precede depressive disorder onset or whether GMV is related to early emerging symptoms or familial depression. To address these questions, we used voxel-based morphometry (VBM) to examine GMV in 85 community-dwelling children (M = 11.12 years, SD = 0.63 years) screened for current and lifetime depression. Associations between children\u27s depressive symptoms (self- and mother-report of children\u27s symptoms), children\u27s maternal depression history, and GMV were examined. Although maternal depression history was unrelated to children\u27s GMV, child GMV in the orbitofrontal cortex (OFC) was negatively related to children\u27s self-reported depressive symptoms, using both a priori ROI and whole-brain analyses. Moderated regression analyses indicated that girls’ GMV was negatively related to girls’ depressive symptoms (as indexed by both self- and mother-report of girls’ symptoms), whereas boys’ symptoms were positively related to GMV. Our findings suggest that brain morphology in the OFC, a region with functional roles in processes relevant to depressive symptoms (i.e., reward-based learning and reward processing), is associated with early depressive symptoms prior to the development of clinically significant depression

Characterizing and Predicting Canadian Adolescents’ Internalizing Symptoms In The First Year Of The COVID-19 Pandemic

To date, most longitudinal studies of adolescents’ internalizing symptoms during the COVID-19 pandemic include few time points, limiting knowledge about the long-term course of adolescents’ mental health during the pandemic. Moreover, examining intraindividual variability in symptoms, which may have important implications for adolescents’ adjustment beyond mean or “typical” symptoms, requires multiple time points. We examined the course of internalizing symptoms in 271 Ontario adolescents (mean n = 193 across time points) during the first year of the pandemic (March 2020–April 2021) via mixed-effect location scale models, drawing upon established internalizing symptom risk factors as predictors of mean trends and intraindividual variability. Adolescents’ internalizing symptoms were relatively stable and generally low over the first year of the pandemic, with severity peaking in February and April 2021. Girls showed more symptoms on average and greater intraindividual variability in symptoms. Parents’ depressive symptoms predicted intraindividual variability in adolescents’ anxious and depressive symptoms. Adolescents’ symptoms were stable and generally below clinical cutoffs. However, female adolescents and those whose parents experienced more depressive symptoms were most vulnerable to the stress of the pandemic. Implications for intervention and prevention efforts are discussed

Maternal Depression, Child Temperament, and Early-Life Stress Predict Never-Depressed Preadolescents’ Functional Connectivity During a Negative-Mood Induction

Understanding the development of depression can inform etiology and prevention/intervention. Maternal depression and maladaptive patterns of temperament (e.g., low positive emotionality [PE] or high negative emotionality, especially sadness) are known to predict depression. Although it is unclear how these risks cause depression, altered functional connectivity (FC) during negative-emotion processing may play an important role. We investigated whether maternal depression and age-3 emotionality predicted FC during negative mood reactivity in never-depressed preadolescents and whether these relationships were augmented by early-life stress. Maternal depression predicted decreased medial prefrontal cortex (mPFC)–amygdala and mPFC–insula FC but increased mPFC–posterior cingulate cortex (PCC) FC. PE predicted increased dorsolateral prefrontal cortex–amygdala FC, whereas sadness predicted increased PCC-based FC in insula, orbitofrontal cortex, and anterior cingulate cortex (ACC). Sadness was more strongly associated with PCC–insula and PCC–ACC FC as early stress increased. Findings indicate that early depression risks may be mediated by FC underlying negative-emotion processing

Steroids and bronchodilators for acute bronchiolitis in the first two years of life: systematic review and meta-analysis

Objective To evaluate and compare the efficacy and safety of bronchodilators and steroids, alone or combined, for the acute management of bronchiolitis in children aged less than 2 years