532 research outputs found

    Improved local planning for reservoir-oriented recreation opportunities

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    Water-based recreation is becoming an increasingly important aspect of water-resources management. However, there is a great deal of uncertainty about its local socio-economic impact. This uncertainty has played a key role in debates over the construction of reservoirs in Illinois. While much attention has been given to predicting expected impacts of reservoirs, there has been little investigation of the actual impacts, and very little attention has been given to evaluating the effectiveness of various approaches to dealing with those local impacts that do indeed result from water-resources-management projects. This study looks at the actual recreation-induced local impacts of Lake Shelbyville, a multipurpose reservoir constructed by the U. S. Army Corps of Engineers in central Illinois. The reservoir began filling in 1969 and is a major recreation attraction (three million visitor days annually) in a predominately agricultural region. The study is exploratory. It identifies significant impacts and suggests how these impacts may be predicted and dealt with. Significant attention is given to impacts on local government costs and revenues as well as needed intergovernmental cooperation. It is clear that local impacts were significantly different from what was expected and that local residents and recreationists using the lake could benefit from improvements in local planning and intergovernmental cooperation.U.S. Department of the InteriorU.S. Geological SurveyOpe

    Individual differences in the nature of conditioned behavior across a conditioned stimulus: adaptation and application of a model

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    Pavlovian conditioning procedures produce marked individual differences in the form of conditioned behavior. For example, when rats are given conditioning trials in which the temporary insertion of a lever into an operant chamber (the conditioned stimulus, CS) is paired with the delivery of food (the unconditioned stimulus, US), they exhibit knowledge of the leverfood relationship in different ways. For some rats (known as sign-trackers) interactions with the lever dominate, while for others (goal-trackers) approaching the food well dominates. A formal model of Pavlovian conditioning (HeiDI) attributes such individual differences in behavior to variations in the perceived salience of the CS and US. An application of the model in which the perceived salience of the CS declines (i.e., adapts) across its duration, predicts changes in these individual differences within the presentation of the CS: The sign-tracking bias is predicted to decline and goal-tracking bias is predicted to increase across the presentation of a lever. The accuracy of these predictions was confirmed though analysis of archival data from female and male rats

    Elaboration of a model of Pavlovian learning and performance: HeiDI

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    The model elaborated here adapts the influential pooled error term, first described by Allan R. Wagner and his colleague Robert A. Rescorla, to govern the formation of reciprocal associations between any pair of stimuli that are presented on a given trial. In the context of Pavlovian conditioning, these stimuli include various conditioned and unconditioned stimuli. This elaboration enables the model to deal with cue competition phenomena, including the relative validity effect, and evidence implicating separate error terms and attentional processes in association formation. The model also includes a performance rule, which provides a natural basis for (individual) variation in the strength and nature of conditioned behaviors that are observed in Pavlovian conditioning procedures. The new model thereby begins to address theoretical and empirical issues that were apparent when the Rescorla-Wagner model was first described, together with research inspired by the model over ensuing 50 years

    Acquisition of a Multi-User Thin Film Synthesis and Processing Facility

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    A state-of-the-art advanced materials synthesis and processing facility focusing on the growth and fabrication of ceramic- based thin film materials will be funded with the assistance of the Academic Research Infrastructure Program. The facility will include a multi-technique thin film materials synthesis chamber equipped with a microwave plasma source, effusion cells, electron beam evaporators, magnetron sputter sources, and a Kauffman ion source. Characterization capabilities will include in-situ reflection high energy electron diffraction (RHEED), mass spectrometry for controlling growth processes, X-ray photoelectron spectroscopy (XPS), and a novel Hall probe for in- situ film characterization. Three major areas of research will be impacted significantly by the facility, namely 1) solid state micro-sensors, 2) nanomechanics of materials, and 3) surfaces and interfaces in hetero-epitaxial oxide systems. In the sensor work, which has connections with local industry, the synthesis and processing of well-defined doped metal-oxide films will be developed with the goal of understanding and controlling the molecular scale mechanisms by which surface microstructure, dopant type, and operating temperature influence sensor performance. A broad based advanced materials synthesis and processing facility for the growth and fabrication of ceramic-based thin films will be operated for the study of solid state microsensors based on metal-oxide ceramic films. The nanomechanics of these ceramic thin films will be studied, as well as the surfaces and interfaces occurring in heteroepitaxial oxide systems

    Reactions of Sandhill Cranes Approaching a Marked Transmission Power Line

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    Sandhill cranes Antigone canadensis, formerly Grus canadensis, are of widespread management focus, particularly where collisions with power lines are an important cause of mortality. Collision mitigation focuses on marking power lines to increase visibility, but collisions persist, perhaps because power line markers are not sufficiently visible in all conditions. Our objective was to compare reaction distances and reaction behaviors during daylight when power lines are presumably more visible, and during darkness when power lines are less visible. The power line we studied was fitted with glow-in-the-dark power line markers intended to increase nocturnal visibility. We found that during daylight, flocks generally avoided the power line by climbing gradually and passed above without making sudden evasive maneuvers. During darkness, flocks, particularly small flocks, were almost equally likely to make sudden evasive maneuvers as to climb gradually. Collision monitoring on the power line we studied conducted concurrent to our study indicated that 94% of collisions occurred during darkness, linking the behaviors we observed to actual mortality. Sandhill cranes also reacted at greater distances and with fewer sudden evasive maneuvers to the glow-in-the-darkmarked power line we studied than to nearby power lines without glowing markers evaluated in a prior study, suggesting that either glowing markers, smaller gaps between markers, or both, improved sandhill cranes’ ability to perceive and react to the power line we studied. By correlating behavioral observations with mortality, our study indicates that proactive low-intensity behavioral observations might be useful surrogates to reactive high-intensity carcass searches in identifying high-risk spans. This approach may also be effective for other species

    HeiDI: A model for Pavlovian learning and performance with reciprocal associations

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    Associative treatments of how Pavlovian conditioning affects conditioned behavior are rudimentary: A simple ordinal mapping is held to exist between the strength of an association (V) between a conditioned stimulus (CS) and an unconditioned stimulus (US; i.e., VCS-US) and conditioned behavior in a given experimental preparation. The inadequacy of this simplification is highlighted by recent studies that have taken multiple measures of conditioned behavior: Different measures of conditioned behavior provide the basis for drawing opposite conclusions about VCS-US across individual animals. Here, we develop a simple model involving reciprocal associations between the CS and US (VCS-US and VUS-CS) that simulates these qualitative individual differences in conditioned behavior. The new model, HeiDI (How excitation and inhibition Determine Ideo-motion), enables a broad range of phenomena to be accommodated, which are either beyond the scope of extant models or require them to appeal to additional (learning) processes. It also provides an impetus for new lines of inquiry and generates novel predictions

    Associative change in Pavlovian conditioning: a re-appraisal

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    Robert A. Rescorla changed how Pavlovian conditioning was studied and interpreted. His empirical contributions were fundamental and theoretically driven. One involved testing a central tenet of the model that he developed with Allan R. Wagner. The Rescorla-Wagner learning rule uses a pooled error term to determine changes in a directional association between the representations of the conditioned stimulus (CS) and unconditioned stimulus (US). This learning rule predicts that 2 equally salient CSs (A and B) will undergo equivalent associative change when they are conditioned in compound (i.e., AB→US). Rescorla’s results suggested that this was not the case (e.g., Rescorla, 2000). Here, we show that these results can be reconciled with a model that uses a learning rule with a pooled error term once that rule is applied equivalently to all of the stimuli presented on a given trial, and the resulting reciprocal associations (directly and indirectly) contribute to performance. This model, called HeiDI, integrates several features of Rescorla’s research and theorizing while addressing an issue that he recognized required further analysis: how learning is translated into performance

    Individual variation in the vigor and form of Pavlovian conditioned responses: analysis of a model system

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    Pavlovian conditioning results in individual variation in the vigor and form of acquired behaviors. Here, we describe a general-process model of associative learning (HeiDI; How excitation and inhibition determine ideo-motion) that provides an analysis for such variation together with a range of other important group-level phenomena. The model takes as its starting point the idea that pairings of a conditioned stimulus (CS) and an unconditioned stimulus (US) result in the formation of reciprocal associations between their central representations. The asymptotic values of these associations and the rate at which these are reached are held to be influenced by the perceived salience of the CS (αCS) and US (βUS). Importantly, whether this associative knowledge is exhibited in behavior that reflects the properties of the CS (e.g., sign-tracking) or US (e.g., goal-tracking) is also influenced by the relative values of αCS and βUS. In this way, HeiDI provides an analysis for both quantitative and qualitative individual differences generated by Pavlovian conditioning procedures

    Tracking Pediatric Asthma:The Massachusetts Experience Using School Health Records

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    The Massachusetts Department of Public Health, in collaboration with the U.S. Centers for Disease Control and Prevention Environmental Public Health Tracking Program, initiated a 3-year statewide project for the routine surveillance of asthma in children using school health records as the primary data source. School district nurse leaders received electronic data reporting forms requesting the number of children with asthma by grade and gender for schools serving grades kindergarten (K) through 8. Verification efforts from an earlier community-level study comparing a select number of school health records with primary care provider records demonstrated a high level of agreement (i.e., > 95%). First-year surveillance targeted approximately one-half (n = 958 schools) of all Massachusetts’s K–8 schools. About 78% of targeted school districts participated, and 70% of the targeted schools submitted complete asthma data. School nurse–reported asthma prevalence was as high as 30.8% for schools, with a mean of 9.2%. School-based asthma surveillance has been demonstrated to be a reliable and cost-effective method of tracking disease through use of an existing and enhanced reporting structure
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