10,947 research outputs found

    Frontostriatal Maturation Predicts Cognitive Control Failure to Appetitive Cues in Adolescents

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    Adolescent risk-taking is a public health issue that increases the odds of poor lifetime outcomes. One factor thought to influence adolescents' propensity for risk-taking is an enhanced sensitivity to appetitive cues, relative to an immature capacity to exert sufficient cognitive control. We tested this hypothesis by characterizing interactions among ventral striatal, dorsal striatal, and prefrontal cortical regions with varying appetitive load using fMRI scanning. Child, teen, and adult participants performed a go/no-go task with appetitive (happy faces) and neutral cues (calm faces). Impulse control to neutral cues showed linear improvement with age, whereas teens showed a nonlinear reduction in impulse control to appetitive cues. This performance decrement in teens was paralleled by enhanced activity in the ventral striatum. Prefrontal cortical recruitment correlated with overall accuracy and showed a linear response with age for no-go versus go trials. Connectivity analyses identified a ventral frontostriatal circuit including the inferior frontal gyrus and dorsal striatum during no-go versus go trials. Examining recruitment developmentally showed that teens had greater between-subject ventral-dorsal striatal coactivation relative to children and adults for happy no-go versus go trials. These findings implicate exaggerated ventral striatal representation of appetitive cues in adolescents relative to an intermediary cognitive control response. Connectivity and coactivity data suggest these systems communicate at the level of the dorsal striatum differentially across development. Biased responding in this system is one possible mechanism underlying heightened risk-taking during adolescence

    Merit Motives and Government Intervention: Public Finance in Reverse

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    A common view in public finance is that there is an efficiency-redistribution tradeoff in which distortions are tolerated in order to redistribute income. However, the fact that so much public- and private redistributive activity involves in-kind transfers rather than cash may be indicative of merit motives on the part of the payers rather than a preference for the well-being of the recipients. Efficiency-enhancing public policy in a merit good economy has the primary purpose of creating distortions and may only redistribute income from rich to poor in order to create those distortions the reverse of the conventional efficiency-redistribution tradeoff. We discuss why the largest programs on the federal and local level in the US including Social Security, Medicare and Medicaid, and Public Schooling seem consistent with the reverse tradeoff rather than the classic one. Transfers are not lump sum in a merit good economy, and explicitly accounting for this when calculating tax incidence reduces the estimated progressivity of government policy. As one example, we calibrate the conventional life-cycle model to show how the amount of over-saving induced on the poor by Social Security hurts them at least as much as the progressive' benefits help them. When the distortions outweigh fiscal transfers in this manner, the classic efficiency-redistribution tradeoff cannot justify the program and the program is far less progressive than conventional analysis suggests.

    Log-Concave Duality in Estimation and Control

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    In this paper we generalize the estimation-control duality that exists in the linear-quadratic-Gaussian setting. We extend this duality to maximum a posteriori estimation of the system's state, where the measurement and dynamical system noise are independent log-concave random variables. More generally, we show that a problem which induces a convex penalty on noise terms will have a dual control problem. We provide conditions for strong duality to hold, and then prove relaxed conditions for the piecewise linear-quadratic case. The results have applications in estimation problems with nonsmooth densities, such as log-concave maximum likelihood densities. We conclude with an example reconstructing optimal estimates from solutions to the dual control problem, which has implications for sharing solution methods between the two types of problems

    An Australian National Compact – Something old, something new?

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    The Australian Labor Party (ALP) formed government under Prime Minister Kevin Rudd in 2007 promising to consult with the not-for-profit sector on the development of a national compact. It was the government’s aim to forge a new settlement with the sector after eleven years of Liberal/National Coalition government during which contractual governance rather than relational governance was the norm. The provenance of the National Compact, launched in March 2010, can be traced back to similar framework documents for inter-sectoral cooperation in the United Kingdom (principally, The Compact) and Canada (the Accord). The National Compact) cannot be explained solely in terms of policy diffusion or the predilection of centre-right political parties for policy instruments of this sort. Rather, explanation requires a more nuanced contextual analysis of the political and policy environment within which these frameworks emerged. In this article we compare the range of factors contributing to the development of The Compact (UK), the Accord) (Canada) and the National Compact (Australia). We apply a similar analysis to policy frameworks in selected Australian states. We conclude that compacts arrive on the policy agenda via the opening of policy windows and through the actions of policy entrepreneurs. Policy windows and the attention of policy entrepreneurs might be both contextual and therefore, time-limited. We consider the range of factors that appear to have a bearing on the impact and durability of inter-sectoral policy frameworks in each jurisdiction in order to draw tentative conclusions about the prospects for the Australian National Compac

    Impact of Cleaning Frequency on Nitrogen Balance in Open Feedlot Pens

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    Pen cleaning frequency of feedlot pens was evaluated during the summer of 2001 and 2002. Dry matter, organic matter and nitrogen recoveries were evaluated on a per head basis. Cleaning pens monthly compared to cleaning at the end of the feeding period resulted in significantly more DM, OM and N recovered. Cleaning pens every month increased N removal by 7.0 lb per steer (49.9% increase) above manure N removed at the end of the feeding period

    Behavioral Assessment of Emotion Discrimination, Emotion Regulation, and Cognitive Control in Childhood, Adolescence, and Adulthood

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    Emotion discrimination, emotion regulation, and cognitive control are three related, yet separable processes that emerge over the course of development. The current study tested 100 children, adolescents, and adults on an Emotional Go/Nogo task, illustrating the ability of this paradigm to identify the unique developmental patterns for each of these three processes in the context of both positive (happy) and negative emotions (fear, sad, and anger), across three different age groups. Consistent with previous literature, our findings show that emotion discrimination and regulatory abilities (both cognitive control and emotion regulation) improve steadily for each age group, with each age group showing unique patterns of performance. The findings suggest that emotion regulation is constructed from basic cognition control and emotion discrimination skills. The patterns of behavior from the Emotional Go/Nogo task provide normative benchmark data across a wide range of emotions that can be used for future behavioral and neuroimaging studies that examine the developmental construction of emotion regulatory processes

    Implications of government funding of advocacy for third-sector independence and exploration of alternative advocacy funding models

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    This paper examines the effect of funding contracts on the capacity of third-sector organizations to effectively advocate. The relationship is not simple or obvious, with some organizations reporting 'mature relationships' with particular (state) departments, and others reporting difficulty with state or federal government jurisdictions. The paper spells out the negative effects of conflating service funding and advocacy. The paper concludes by exploring alternative institutional arrangements for the resourcing of advocacy including the establishment of a Public Interest Fund administered independently of any government department, one not requiring specific service contracts but rather evidence that it is advocating for the broader public good

    Laminar flow of two miscible fluids in a simple network

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    When a fluid comprised of multiple phases or constituents flows through a network, non-linear phenomena such as multiple stable equilibrium states and spontaneous oscillations can occur. Such behavior has been observed or predicted in a number of networks including the flow of blood through the microcirculation, the flow of picoliter droplets through microfluidic devices, the flow of magma through lava tubes, and two-phase flow in refrigeration systems. While the existence of non-linear phenomena in a network with many inter-connections containing fluids with complex rheology may seem unsurprising, this paper demonstrates that even simple networks containing Newtonian fluids in laminar flow can demonstrate multiple equilibria. The paper describes a theoretical and experimental investigation of the laminar flow of two miscible Newtonian fluids of different density and viscosity through a simple network. The fluids stratify due to gravity and remain as nearly distinct phases with some mixing occurring only by diffusion. This fluid system has the advantage that it is easily controlled and modeled, yet contains the key ingredients for network non-linearities. Experiments and 3D simulations are first used to explore how phases distribute at a single T-junction. Once the phase separation at a single junction is known, a network model is developed which predicts multiple equilibria in the simplest of networks. The existence of multiple stable equilibria is confirmed experimentally and a criteria for their existence is developed. The network results are generic and could be applied to or found in different physical systems
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