432 research outputs found

    Claiming Space, Redefining Politics: Urban Protest and Grassroots Power in Bolivia

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    This dissertation analyzes the role of space-claiming protests by primarily left grassroots social movements in Bolivia\u27s current political transformation. Space claiming includes mass protests that physically control or symbolically claim urban space through occupations of plazas and roads, sit-ins, blockades, and other measures. As a theoretical construct, space claiming brings together tactics of collective action and meanings of public spaces, and looks at the consequences of their interaction. This dissertation is based on ethnographic engagement and oral interviews with protest participants and their state interlocutors during twelve months of fieldwork and archival research. By using detailed ethnographic evidence--of social life as experienced through the human body, the meanings attached to places, and social movement practices--it explains how grassroots movements exerted leverage upon the state through pivotal protest events. This study shows that the political import of these protests arises from their interruption of commercially important flows and appropriation of meaning-laden spaces in cities like Cochabamba and Sucre. Social movements used spatial meanings, protest symbols and rhetoric to build an imagined community of interest and sovereignty, which claims the right to direct the political course of the state. The presence of indigenous bodies, symbols, and politics in these spaces challenged and inverted their longstanding exclusion from power. The largest mobilizations exercised control over aspects of daily life that would otherwise be organized by the state. These interruptions of commerce and circulation, and the collective gatherings that directed them posed an alternate possibility of sovereignty. This put the existing order into question, forcing shifts in political life to resolve the temporary crises. At the same time, the practices of disruption were added to the routines of political practice, making future officeholders even less able to maneuver independently of the grassroots base. This dissertation explains why and how space-claiming protests work as political tools, and the ways that practices of cooperation, coordination, and decision making within protest have become models for Bolivia\u27s political culture. In doing so, it contributes to the study of social protest in Latin America, the theory of social movement practice, and the geographic study of political protest

    Mechanisms underlying the sperm quality advantage in sperm competition and cryptic female choice in Drosophila melanogaster

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    Contrary to early predictions of sperm competition theory, postcopulatory sexual selection favoring increased investment per sperm (e.g., sperm size, sperm quality) has been demonstrated in numerous organisms. Recent findings reveal that sperm production strategies are highly variable, with males of some species producing relatively few, giant sperm. We empirically demonstrate for Drosophila melanogaster that both sperm quality and sperm quantity independently contribute to competitive male fertilization success. The interaction between sperm quality and quantity suggests an internal positive reinforcement on selection for sperm quality, with selection predicted to intensify as investment per sperm increases and the number of sperm competing declines. The mechanism underlying the sperm quality advantage is elucidated through examination of the relationship between female sperm-storage organ morphology and the differential organization of different length sperm within the organ. Our results exemplify that primary sex cells can bear secondary sexual straits

    The utility of twins in developmental cognitive neuroscience research: How twins strengthen the ABCD research design

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    The ABCD twin study will elucidate the genetic and environmental contributions to a wide range of mental and physical health outcomes in children, including substance use, brain and behavioral development, and their interrelationship. Comparisons within and between monozygotic and dizygotic twin pairs, further powered by multiple assessments, provide information about genetic and environmental contributions to developmental associations, and enable stronger tests of causal hypotheses, than do comparisons involving unrelated children. Thus a sub-study of 800 pairs of same-sex twins was embedded within the overall Adolescent Brain and Cognitive Development (ABCD) design. The ABCD Twin Hub comprises four leading centers for twin research in Minnesota, Colorado, Virginia, and Missouri. Each site is enrolling 200 twin pairs, as well as singletons. The twins are recruited from registries of all twin births in each State during 2006–2008. Singletons at each site are recruited following the same school-based procedures as the rest of the ABCD study. This paper describes the background and rationale for the ABCD twin study, the ascertainment of twin pairs and implementation strategy at each site, and the details of the proposed analytic strategies to quantify genetic and environmental influences and test hypotheses critical to the aims of the ABCD study. Keywords: Twins, Heritability, Environment, Substance use, Brain structure, Brain functio

    Cognitive Effort Avoidance in Veterans with Suicide Attempt Histories

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    Suicide attempts (SA) are increasing in the United States, especially in veterans. Discovering individual cognitive features of the subset of suicide ideators who attempt suicide is critical. Cognitive theories attribute SA to facile schema-based negative interpretations of environmental events. Over-general autobiographical memory and facile solutions in problem solving tasks in SA survivors suggest that aversion to expending cognitive effort may be a neurobehavioral marker of SA risk. In veterans receiving care for mood disorder, we compared cognitive effort discounting and evidence-gathering in a beads task between veterans with (SAHx+; n = 26) versus without (SAHx-; n = 22) a history of SA. Groups did not differ in depressed mood or in a proxy metric of premorbid intelligence. Compared to SAHx- participants, SAHx+ participants self-reported significantly more severe cognitive problems in most domains, and also eschewed choice to earn higher monetary reward if earning it required a slightly increased working memory (WM) demand relative to an easy WM task. There was no group difference, however, in extent of evidence-gathering before declaring a conclusion in a beads task. These preliminary data suggest that aversion to expenditure of cognitive effort, potentially as a component of cognitive difficulties, may be a marker for SA risk

    Reliability and stability challenges in ABCD task fMRI data

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    Trait stability of measures is an essential requirement for individual differences research. Functional MRI has been increasingly used in studies that rely on the assumption of trait stability, such as attempts to relate task related brain activation to individual differences in behavior and psychopathology. However, recent research using adult samples has questioned the trait stability of task-fMRI measures, as assessed by test-retest correlations. To date, little is known about trait stability of task fMRI in children. Here, we examined within-session reliability and long-term stability of individual differences in task-fMRI measures using fMRI measures of brain activation provided by the adolescent brain cognitive development (ABCD) Study Release v4.0 as an individual\u27s average regional activity, using its tasks focused on reward processing, response inhibition, and working memory. We also evaluated the effects of factors potentially affecting reliability and stability. Reliability and stability (quantified as the ratio of non-scanner related stable variance to all variances) was poor in virtually all brain regions, with an average value of 0.088 and 0.072 for short term (within-session) reliability and long-term (between-session) stability, respectively, in regions of interest (ROIs) historically-recruited by the tasks. Only one reliability or stability value in ROIs exceeded the \u27poor\u27 cut-off of 0.4, and in fact rarely exceeded 0.2 (only 4.9%). Motion had a pronounced effect on estimated reliability/stability, with the lowest motion quartile of participants having a mean reliability/stability 2.5 times higher (albeit still \u27poor\u27) than the highest motion quartile. Poor reliability and stability of task-fMRI, particularly in children, diminishes potential utility of fMRI data due to a drastic reduction of effect sizes and, consequently, statistical power for the detection of brain-behavior associations. This essential issue urgently needs to be addressed through optimization of task design, scanning parameters, data acquisition protocols, preprocessing pipelines, and data denoising methods

    The structure of cognition in 9 and 10 year-old children and associations with problem behaviors: Findings from the ABCD study\u27s baseline neurocognitive battery

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    The Adolescent Brain Cognitive Development (ABCD) study is poised to be the largest single-cohort long-term longitudinal study of neurodevelopment and child health in the United States. Baseline data on N= 4521 children aged 9-10 were released for public access on November 2, 2018. In this paper we performed principal component analyses of the neurocognitive assessments administered to the baseline sample. The neurocognitive battery included seven measures from the NIH Toolbox as well as five other tasks. We implemented a Bayesian Probabilistic Principal Components Analysis (BPPCA) model that incorporated nesting of subjects within families and within data collection sites. We extracted varimax-rotated component scores from a three-component model and associated these scores with parent-rated Child Behavior Checklist (CBCL) internalizing, externalizing, and stress reactivity. We found evidence for three broad components that encompass general cognitive ability, executive function, and learning/memory. These were significantly associated with CBCL scores in a differential manner but with small effect sizes. These findings set the stage for longitudinal analysis of neurocognitive and psychopathological data from the ABCD cohort as they age into the period of maximal adolescent risk-taking

    The Global Health and Care Worker Compact: Evidence Base and Policy Considerations

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    Background During the COVID-19 pandemic, and recognising the sacrifice of health and care workers alongside discrimination, violence, poor working conditions and other violations of their rights, health and safety, in 2021 the World Health Assembly requested WHO to develop a global health and care worker compact, building on existing normative documentation, to provide guidance to ‘protect health and care workers and safeguard their rights’. Methods A review of existing international law and other normative documents was conducted. We manually searched five main sets of international instruments: (1) International Labour Organization conventions and recommendations; (2) WHO documents; (3) United Nations (UN) human rights treaties and related documents; (4) UN Security Council and General Assembly resolutions and (5) the Geneva Conventions and Additional Protocols. We included only legal or other normative documents with a global or regional focus directly addressing or relevant to health and care workers or workers overall. Results More than 70 documents met our search criteria. Collectively, they fell into four domains, within which we identified 10 distinct areas: (1) preventing harm, encompassing (A) occupational hazards, (B) violence and harassment and (C) attacks in situations of fragility, conflict and violence; (2) inclusivity, encompassing (A) non-discrimination and equality; (3) providing support, encompassing (A) fair and equitable remuneration, (B) social protection and (C) enabling work environments and (4) safeguarding rights, encompassing (A) freedom of association and collective bargaining and (B) whistle-blower protections and freedom from retaliation. Discussion A robust legal and policy framework exists for supporting health and care workers and safeguarding their rights. Specific human rights, the right to health overall, and other binding and non-binding legal documents provide firm grounding for the compact. However, these existing commitments are not being fully met. Implementing the compact will require more effective governance mechanisms and new policies, in partnership with health and care workers themselves

    Adolescents, Adults and Rewards: Comparing Motivational Neurocircuitry Recruitment Using fMRI

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    Background: Adolescent risk-taking, including behaviors resulting in injury or death, has been attributed in part to maturational differences in mesolimbic incentive-motivational neurocircuitry, including ostensible oversensitivity of the nucleus accumbens (NAcc) to rewards. Methodology/Principal Findings: To test whether adolescents showed increased NAcc activation by cues for rewards, or by delivery of rewards, we scanned 24 adolescents (age 12–17) and 24 adults age (22–42) with functional magnetic resonance imaging while they performed a monetary incentive delay (MID) task. The MID task was configured to temporally disentangle potential reward or potential loss anticipation-related brain signal from reward or loss notification-related signal. Subjects saw cues signaling opportunities to win or avoid losing 0,0, .50, or $5 for responding quickly to a subsequent target. Subjects then viewed feedback of their trial success after a variable interval from cue presentation of between 6 to17 s. Adolescents showed reduced NAcc recruitment by reward-predictive cues compared to adult controls in a linear contrast with non-incentive cues, and in a volume-of-interest analysis of signal change in the NAcc. In contrast, adolescents showed little difference in striatal and frontocortical responsiveness to reward deliveries compared to adults. Conclusions/Significance: In light of divergent developmental difference findings between neuroimaging incentive paradigms (as well as at different stages within the same task), these data suggest that maturational differences i
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