7,824 research outputs found

    A historical case study of Lowell Elementary School in Missoula Montana

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    An Overview on Institutionalism and Decentralized Decision-Making

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    Human actions, interactions and decisions should have a certain degree of predictability that can be obtained by establishing rules. Institutions, in general, are defined by sets of rules known by the public and applicable for the community. Their existence is essential for the economic activity, as it cannot develop in a vacuum. At the same time, the type and the quality of institutions make the difference in implementing economic aspirations of individuals and in supporting economic overall growth. Institutions provide a minimum of regulations that in conjunction with the particularities and the interests of individuals and communities become the foundation for economic, political and social decision-making processes.

    Population, Greenspace, and Development:Conversion Patterns in the Great Lakes Region

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    In this brief, authors Mark Ducey, Kenneth Johnson, Ethan Belair, and Barbara Cook combine demographic, land-cover, and other spatial data to estimate the incidence and extent of conversion from greenspace (forestland, shrublands, and grasslands) to development in the Great Lakes states. They report that greenspace conversions to developed land are most common in areas where greenspace is already limited. Population density strongly influences the conversion of greenspace to development. Conversions are most likely to occur on the urban periphery and in high-amenity rural areas. This research contributes to a better understanding of the linkages between demographic and land-cover change and provides facts that can inform policy aimed at balancing development and greenspace conservation

    Forests in Flux: The Effects of Demographic Change on Forest Cover in New England and New York

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    This brief contributes to a better understanding of the linkages between demographic and forest cover change so as to inform policy efforts aimed at maintaining existing forested areas in and around sprawling urban centers. Authors Mark Ducey, Kenneth Johnson, Ethan Belair, and Miranda Mockrin report that forest cover has declined throughout New England and New York over the last decade. In rural areas, forest loss is primarily due to commercial timber harvesting and represents a temporary change. Conversely, forest cover decline in urban areas is usually the result of development and is likely to be permanent. Forest cover change is strongly linked to demographic variables throughout this region. Forest cover loss is most pronounced along the urban fringe, where population growth is greatest. Amenity-rich rural areas are also experiencing high rates of population growth and regionally-high rates of forest cover loss. However, the causes of forest cover change in these areas are less certain. Forest cover change has the potential to impact ecosystem services important to both local residents and the larger region

    A POST-TRAUMATIC STRESS DISORDER REVIEW: THE PREVALENCE OF UNDERREPORTING AND THE ROLE OF STIGMA IN THE MILITARY

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    Exposure to traumatic events has been a part of human existence since the beginning of time; however modern lifestyles and developments mean that the majority of the population are spared the affliction of extreme trauma. The military, however, are one subgroup of individuals who are actively and repeatedly exposed to terrifying events on a regular basis, putting them at risk of developing "Post-Traumatic Stress Disorder" (PTSD). Despite this, the prevalence of PTSD reports in the UK military remains lower than its international allies, suggesting this value may be an underestimation of the true prevalence. Wider investigation of the potential causes of this has highlighted the stigmatization of mental illness in the military as the key barrier to the help-seeking behaviours. However, the effect of national de-stigmatization programs on PTSD help seeking is unclear. This review aims to determine the prevalence of PTSD within the UK military in the context of other international powers and examine how stigmatization of mental illness in military may contribute to this. The international value of de-stigmatization programs will be debated and future directions for research suggested

    A POST-TRAUMATIC STRESS DISORDER REVIEW: THE PREVALENCE OF UNDERREPORTING AND THE ROLE OF STIGMA IN THE MILITARY

    Get PDF
    Exposure to traumatic events has been a part of human existence since the beginning of time; however modern lifestyles and developments mean that the majority of the population are spared the affliction of extreme trauma. The military, however, are one subgroup of individuals who are actively and repeatedly exposed to terrifying events on a regular basis, putting them at risk of developing "Post-Traumatic Stress Disorder" (PTSD). Despite this, the prevalence of PTSD reports in the UK military remains lower than its international allies, suggesting this value may be an underestimation of the true prevalence. Wider investigation of the potential causes of this has highlighted the stigmatization of mental illness in the military as the key barrier to the help-seeking behaviours. However, the effect of national de-stigmatization programs on PTSD help seeking is unclear. This review aims to determine the prevalence of PTSD within the UK military in the context of other international powers and examine how stigmatization of mental illness in military may contribute to this. The international value of de-stigmatization programs will be debated and future directions for research suggested

    Analysis and Control of a Variable-Pitch Quadrotor for Agile Flight

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    Fixed-pitch quadrotors are popular research and hobby platforms largely due to their mechanical simplicity relative to other hovering aircraft. This simplicity, however, places fundamental limits on the achievable actuator bandwidth and the possible flight maneuvers. This paper shows that many of these limitations can be overcome by utilizing variable-pitch propellers on a quadrotor. A detailed analysis of the potential benefits of variable-pitch propellers over fixed-pitch propellers for a quadrotor is presented. This analysis is supported with experimental testing to show that variable-pitch propellers, in addition to allowing for generation of reverse thrust, substantially increase the maximum rate of thrust change. A nonlinear, quaternion-based control algorithm for controlling the quadrotor is also presented with an accompanying trajectory generation method that finds polynomial minimum-time paths based on actuator saturation levels. The control law and trajectory generation algorithms are implemented on a custom variable-pitch quadrotor. Several flight tests are shown, which highlight the benefits of a variable-pitch quadrotor over a standard fixed-pitch quadrotor for performing aggressive and aerobatic maneuvers.National Science Foundation (U.S.) (0645960

    Efficient reinforcement learning for robots using informative simulated priors

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    Autonomous learning through interaction with the physical world is a promising approach to designing controllers and decision-making policies for robots. Unfortunately, learning on robots is often difficult due to the large number of samples needed for many learning algorithms. Simulators are one way to decrease the samples needed from the robot by incorporating prior knowledge of the dynamics into the learning algorithm. In this paper we present a novel method for transferring data from a simulator to a robot, using simulated data as a prior for real-world learning. A Bayesian nonparametric prior is learned from a potentially black-box simulator. The mean of this function is used as a prior for the Probabilistic Inference for Learning Control (PILCO) algorithm. The simulated prior improves the convergence rate and performance of PILCO by directing the policy search in areas of the state-space that have not yet been observed by the robot. Simulated and hardware results show the benefits of using the prior knowledge in the learning framework

    Advanced modulation technology development for earth station demodulator applications. Coded modulation system development

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    A jointly optimized coded modulation system is described which was designed, built, and tested by COMSAT Laboratories for NASA LeRC which provides a bandwidth efficiency of 2 bits/s/Hz at an information rate of 160 Mbit/s. A high speed rate 8/9 encoder with a Viterbi decoder and an Octal PSK modem are used to achieve this. The BER performance is approximately 1 dB from the theoretically calculated value for this system at a BER of 5 E-7 under nominal conditions. The system operates in burst mode for downlink applications and tests have demonstrated very little degradation in performance with frequency and level offset. Unique word miss rate measurements were conducted which demonstrate reliable acquisition at low values of Eb/No. Codec self tests have verified the performance of this subsystem in a stand alone mode. The codec is capable of operation at a 200 Mbit/s information rate as demonstrated using a codec test set which introduces noise digitally. The measured performance is within 0.2 dB of the computer simulated predictions. A gate array implementation of the most time critical element of the high speed Viterbi decoder was completed. This gate array add-compare-select chip significantly reduces the power consumption and improves the manufacturability of the decoder. This chip has general application in the implementation of high speed Viterbi decoders

    Determining the Feasibility, Content Validity, and Internal Consistency of a Newly Developed Care Coordination Scale for People with Brain Injury

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    Background: With the increasing complexity of care, people with disabilities and supportive significant others (SSO) must often coordinate key aspects of their own care, but no validated scale currently exists to comprehensively characterize the activities done to manage and coordinate their care. Method: This study aimed to improve the feasibility, acceptability, and content validity of the Care and Service Coordination and Management (CASCAM) scale and to test its internal consistency. Questionnaire items were administered to 23 individuals with acquired brain injury and 17 SSO. Results: Respondents confirmed content validity and that the instrument addresses important care coordination and management issues. The internal consistency of care coordination domains for medical/rehabilitative and independent living needs for people with brain injury and their SSO ranged from α = .774 to .945. Conclusion: Care coordination activities by persons with disabilities, including brain injury, and their SSO are multifaceted but feasibly measurable and should be assessed to improve care
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